Merge branch 'master' into mc-1.13.x

- Adds a CheckStyle configuration which is pretty similar to CC's
   existing one.
 - Add the Gradle license plugin.
 - Ensure the existing source code is compatible with these additional
   checks.

See #239

.github/ISSUE_TEMPLATE/bug_report.md

@@ -1,7 +1,7 @@
 ---
 name: Bug report
 about: Report some misbehaviour in the mod
-
+labels: bug
 ---
 
 <!--

.github/ISSUE_TEMPLATE/feature_request.md

@@ -1,7 +1,7 @@
 ---
 name: Feature request
 about: Suggest an idea or improvement
-
+labels: enhancement
 ---
 
 <!--
@@ -11,4 +11,4 @@ about: Suggest an idea or improvement
 
 ## Useful information to include:
  - Explanation of how the feature/change should work.
- - Some rationale/use case for a feature. I'd like to keep CC:T as minimal as possible, so I like have a solid justification for each feature.
+ - Some rationale/use case for a feature. My general approach to designing new features is to ask yourself "what issue are we trying to solve" and _then_ "is this the best way to solve this issue?".

.github/pull_request_template.md

@@ -0,0 +1,3 @@
+## A quick checklist
+ - If there's a existing issue, please link to it. If not, provide fill out the same information you would in a normal issue - reproduction steps for bugs, rationale for use-case.
+ - If you're working on CraftOS, try to write a few test cases so we can ensure everything continues to work in the future. Tests live in `src/test/resources/test-rom/spec` and can be run with `./gradlew check`.

.gitignore

@@ -15,3 +15,9 @@
 .idea
 .gradle
 *.DS_Store
+
+.classpath
+.project
+.settings/
+bin/
+*.launch

README.md

@@ -1,5 +1,5 @@
 # ![CC: Tweaked](logo.png)
-[![Build Status](https://travis-ci.org/SquidDev-CC/CC-Tweaked.svg?branch=master)](https://travis-ci.org/SquidDev-CC/CC-Tweaked)
+[![Current build status](https://travis-ci.org/SquidDev-CC/CC-Tweaked.svg?branch=master)](https://travis-ci.org/SquidDev-CC/CC-Tweaked "Current build status") [![Download CC: Tweaked on CurseForge](https://cf.way2muchnoise.eu/title/cc-tweaked.svg)](https://minecraft.curseforge.com/projects/cc-tweaked "Download CC: Tweaked on CurseForge")
 
 CC: Tweaked is a fork of [ComputerCraft](https://github.com/dan200/ComputerCraft), adding programmable computers,
 turtles and more to Minecraft.
@@ -9,7 +9,7 @@ ComputerCraft has always held a fond place in my heart: it's the mod which reall
 mod which has kept me playing it for many years. However, development of the original mod has slowed, as the original
 developers have had less time to work on the mod, and moved onto other projects and commitments.
 
-CC:Tweaked (or CC:T for short) is an attempt to continue ComputerCraft's legacy. It's not intended to be a competitor
+CC: Tweaked (or CC:T for short) is an attempt to continue ComputerCraft's legacy. It's not intended to be a competitor
 to CC, nor do I want to take it in a vastly different direction to the original mod. Instead, CC:T focuses on making the
 ComputerCraft experience as _solid_ as possible, ironing out any wrinkles that may have developed over time.
 
@@ -46,8 +46,17 @@ develop CC:T, you'll need to follow these steps:
 
 If you want to run CC:T in a normal Minecraft instance, run `./gradlew build` and copy the `.jar` from `build/libs`.
 
+## Community
+If you need help getting started with CC: Tweaked, want to show off your latest project, or just want to chat about
+ComputerCraft we have a [forum](https://forums.computercraft.cc/) and [Discord guild](https://discord.gg/H2UyJXe)!
+There's also a fairly populated, albeit quiet [IRC channel](http://webchat.esper.net/?channels=#computercraft), if
+that's more your cup of tea.
+
+I'd generally recommend you don't contact me directly (email, DM, etc...) unless absolutely necessary (i.e. in order to
+report exploits). You'll get a far quicker response if you ask the whole community!
+
 ## Using
-If you want to depend on CC:Tweaked, we have a maven repo. However, you should be wary that some functionality is only
+If you want to depend on CC: Tweaked, we have a maven repo. However, you should be wary that some functionality is only
 exposed by CC:T's API and not vanilla ComputerCraft. If you wish to support all variations of ComputerCraft, I recommend
 using [cc.crzd.me's maven](https://cc.crzd.me/maven/) instead.
 
@@ -57,7 +66,7 @@ dependencies {
 }
 
 dependencies {
-  implementation "org.squiddev:cc-tweaked:${mc_version}-${cct_version}"
+  implementation "org.squiddev:cc-tweaked-${mc_version}:${cct_version}"
 }
 ```
 

build.gradle

@@ -9,14 +9,17 @@ buildscript {
     }
     dependencies {
         classpath 'com.google.code.gson:gson:2.8.1'
-        classpath 'net.minecraftforge.gradle:ForgeGradle:3.0.115'
+        classpath 'net.minecraftforge.gradle:ForgeGradle:3.0.117'
         classpath 'net.sf.proguard:proguard-gradle:6.1.0beta2'
         classpath 'org.ajoberstar.grgit:grgit-gradle:3.0.0'
     }
 }
 
 plugins {
-    id 'com.matthewprenger.cursegradle' version '1.2.0'
+    id "checkstyle"
+    id "com.github.hierynomus.license" version "0.15.0"
+    id "com.matthewprenger.cursegradle" version "1.3.0"
+    id "com.github.breadmoirai.github-release" version "2.2.4"
 }
 
 apply plugin: 'net.minecraftforge.gradle'
@@ -87,13 +90,15 @@ configurations {
 }
 
 dependencies {
+    checkstyle "com.puppycrawl.tools:checkstyle:8.21"
+
     minecraft "net.minecraftforge:forge:${mc_version}-${forge_version}"
 
-    compileOnly "mezz.jei:jei-1.13.2:5.0.0.8:api"
+    compileOnly fg.deobf("mezz.jei:jei-1.13.2:5.0.0.20:api")
     // deobfProvided "pl.asie:Charset-Lib:0.5.4.6"
     // deobfProvided "MCMultiPart2:MCMultiPart:2.5.3"
 
-    deobf "mezz.jei:jei-1.13.2:5.0.0.8"
+    runtimeOnly fg.deobf("mezz.jei:jei-1.13.2:5.0.0.20")
 
     shade 'org.squiddev:Cobalt:0.5.0-SNAPSHOT'
 
@@ -142,6 +147,8 @@ import java.util.zip.*
 
 import com.google.gson.GsonBuilder
 import com.google.gson.JsonElement
+import com.hierynomus.gradle.license.tasks.LicenseCheck
+import com.hierynomus.gradle.license.tasks.LicenseFormat
 import org.ajoberstar.grgit.Grgit
 import proguard.gradle.ProGuardTask
 
@@ -164,7 +171,7 @@ task proguard(type: ProGuardTask, dependsOn: jar) {
     dontobfuscate; dontoptimize; keepattributes; keepparameternames
 
     // Proguard will remove directories by default, but that breaks JarMount.
-    keepdirectories 'assets/computercraft/lua**'
+    keepdirectories 'data/computercraft/lua**'
 
     // Preserve ComputerCraft classes - we only want to strip shadowed files.
     keep 'class dan200.computercraft.** { *; }'
@@ -241,6 +248,7 @@ task compressJson(dependsOn: jar) {
         // Copy over all files in the current jar to the new one, running json files from GSON. As pretty printing
         // is turned off, they should be minified.
         new ZipFile(jarPath).withCloseable { inJar ->
+            tempPath.getParentFile().mkdirs()
             new ZipOutputStream(new BufferedOutputStream(new FileOutputStream(tempPath))).withCloseable { outJar ->
                 inJar.entries().each { entry ->
                     if(entry.directory) {
@@ -268,12 +276,91 @@ task compressJson(dependsOn: jar) {
 
 assemble.dependsOn compressJson
 
+/* Check tasks */
+
+license {
+    mapping("java", "SLASHSTAR_STYLE")
+    strictCheck true
+
+    ext.year = Calendar.getInstance().get(Calendar.YEAR)
+}
+
+[licenseMain, licenseFormatMain].forEach {
+    it.configure {
+        include("**/*.java")
+        exclude("dan200/computercraft/api/**")
+        header rootProject.file('config/license/main.txt')
+    }
+}
+
+[licenseTest, licenseFormatTest].forEach {
+    it.configure {
+        include("**/*.java")
+        header rootProject.file('config/license/main.txt')
+    }
+}
+
+task licenseAPI(type: LicenseCheck);
+task licenseFormatAPI(type: LicenseFormat);
+[licenseAPI, licenseFormatAPI].forEach {
+    it.configure {
+        source = sourceSets.main.java
+        include("dan200/computercraft/api/**")
+        header rootProject.file('config/license/api.txt')
+    }
+}
+
+/* Upload tasks */
+
+task checkRelease {
+    group "upload"
+    description "Verifies that everything is ready for a release"
+
+    inputs.property "version", mod_version
+    inputs.file("src/main/resources/data/computercraft/lua/rom/help/changelog.txt")
+    inputs.file("src/main/resources/data/computercraft/lua/rom/help/whatsnew.txt")
+
+    doLast {
+        def ok = true
+
+        // Check we're targetting the current version
+        def whatsnew = new File("src/main/resources/data/computercraft/lua/rom/help/whatsnew.txt").readLines()
+        if (whatsnew[0] != "New features in CC: Tweaked $mod_version") {
+            ok = false
+            project.logger.error("Expected `whatsnew.txt' to target $mod_version.")
+        }
+
+        // Check "read more" exists and trim it
+        def idx = whatsnew.findIndexOf { it == 'Type "help changelog" to see the full version history.' }
+        if (idx == -1) {
+            ok = false
+            project.logger.error("Must mention the changelog in whatsnew.txt")
+        } else {
+            whatsnew = whatsnew.getAt(0 ..< idx)
+        }
+
+        // Check whatsnew and changelog match.
+        def versionChangelog = "# " + whatsnew.join("\n")
+        def changelog = new File("src/main/resources/data/computercraft/lua/rom/help/changelog.txt").getText()
+        if (!changelog.startsWith(versionChangelog)) {
+            ok = false
+            project.logger.error("whatsnew and changelog are not in sync")
+        }
+
+        if (!ok) throw new IllegalStateException("Could not check release")
+    }
+}
+
 curseforge {
     apiKey = project.hasProperty('curseForgeApiKey') ? project.curseForgeApiKey : ''
     project {
         id = '282001'
-        releaseType = 'beta'
+        releaseType = 'release'
         changelog = "Release notes can be found on the GitHub repository (https://github.com/SquidDev-CC/CC-Tweaked/releases/tag/v${mc_version}-${mod_version})."
+
+        relations {
+            incompatible "computercraft"
+        }
     }
 }
 
@@ -330,6 +417,31 @@ uploadArchives {
     }
 }
 
+githubRelease {
+    token project.hasProperty('githubApiKey') ? project.githubApiKey : ''
+    owner 'SquidDev-CC'
+    repo 'CC-Tweaked'
+    targetCommitish { Grgit.open(dir: '.').branch.current().name }
+
+    tagName "v${mc_version}-${mod_version}"
+    releaseName "[${mc_version}] ${mod_version}"
+    body {
+        "## " + new File("src/main/resources/data/computercraft/lua/rom/help/whatsnew.txt")
+            .readLines()
+            .takeWhile { it != 'Type "help changelog" to see the full version history.' }
+            .join("\n").trim()
+    }
+    prerelease false
+}
+
+def uploadTasks = ["uploadArchives", "curseforge", "githubRelease"]
+uploadTasks.forEach { tasks.getByName(it).dependsOn checkRelease }
+
+task uploadAll(dependsOn: uploadTasks) {
+    group "upload"
+    description "Uploads to all repositories (Maven, Curse, GitHub release)"
+}
+
 test {
     useJUnitPlatform()
     testLogging {
@@ -343,5 +455,9 @@ gradle.projectsEvaluated {
     tasks.withType(JavaCompile) {
         options.compilerArgs << "-Xlint" << "-Xlint:-processing" // Causes Forge build to fail << "-Werror"
     }
+
+    tasks.withType(LicenseFormat) {
+        outputs.upToDateWhen { false }
+    }
 }
 

config/checkstyle/checkstyle.xml

@@ -0,0 +1,159 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE module PUBLIC
+    "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
+    "https://checkstyle.org/dtds/configuration_1_3.dtd">
+<module name="Checker">
+    <property name="tabWidth" value="4"/>
+    <property name="charset" value="UTF-8" />
+
+    <module name="SuppressionFilter">
+        <property name="file" value="config/checkstyle/suppressions.xml" />
+    </module>
+
+    <module name="TreeWalker">
+        <!-- Annotations -->
+        <module name="AnnotationLocation" />
+        <module name="AnnotationUseStyle" />
+        <module name="MissingDeprecated">
+            <property name="skipNoJavadoc" value="true" />
+        </module>
+        <module name="MissingOverride" />
+
+        <!-- Blocks -->
+        <module name="EmptyBlock" />
+        <module name="EmptyCatchBlock">
+            <property name="exceptionVariableName" value="ignored" />
+        </module>
+        <module name="LeftCurly">
+            <property name="option" value="nl" />
+            <!-- The defaults, minus lambdas. -->
+            <property name="tokens" value="ANNOTATION_DEF,CLASS_DEF,CTOR_DEF,ENUM_CONSTANT_DEF,ENUM_DEF,INTERFACE_DEF,LITERAL_CASE,LITERAL_CATCH,LITERAL_DEFAULT,LITERAL_DO,LITERAL_ELSE,LITERAL_FINALLY,LITERAL_FOR,LITERAL_IF,LITERAL_SWITCH,LITERAL_SYNCHRONIZED,LITERAL_TRY,LITERAL_WHILE,METHOD_DEF,OBJBLOCK,STATIC_INIT" />
+        </module>
+        <module name="NeedBraces">
+            <property name="allowSingleLineStatement" value="true"/>
+        </module>
+        <module name="RightCurly">
+            <property name="option" value="alone" />
+        </module>
+
+        <!-- Class design. As if we've ever followed good practice here. -->
+        <module name="FinalClass" />
+        <module name="InterfaceIsType" />
+        <module name="MutableException" />
+        <module name="OneTopLevelClass" />
+
+        <!-- Coding -->
+        <module name="ArrayTrailingComma" />
+        <module name="EqualsHashCode" />
+        <!-- FallThrough does not handle unreachable code well -->
+        <module name="IllegalInstantiation" />
+        <module name="IllegalThrows" />
+        <module name="ModifiedControlVariable" />
+        <module name="NoClone" />
+        <module name="NoFinalizer" />
+        <module name="OneStatementPerLine" />
+        <module name="PackageDeclaration" />
+        <module name="SimplifyBooleanExpression" />
+        <module name="SimplifyBooleanReturn" />
+        <module name="StringLiteralEquality" />
+        <module name="UnnecessaryParentheses" />
+
+        <!-- Imports -->
+        <module name="CustomImportOrder" />
+        <module name="IllegalImport" />
+        <module name="RedundantImport" />
+        <module name="UnusedImports" />
+
+        <!-- Javadoc -->
+        <module name="AtclauseOrder" />
+        <!-- TODO: Cleanup our documentation before enabling JavadocMethod, JavadocStyle, JavadocType and SummaryJavadoc. -->
+        <module name="NonEmptyAtclauseDescription" />
+        <module name="SingleLineJavadoc" />
+
+        <!-- Misc -->
+        <module name="ArrayTypeStyle" />
+        <module name="CommentsIndentation" />
+        <module name="Indentation" />
+        <module name="OuterTypeFilename" />
+
+        <!-- Modifiers -->
+        <module name="ModifierOrder" />
+        <module name="RedundantModifier" />
+
+        <!-- Naming -->
+        <module name="ClassTypeParameterName" />
+        <module name="InterfaceTypeParameterName" />
+        <module name="LambdaParameterName" />
+        <module name="LocalFinalVariableName" />
+        <module name="LocalVariableName" />
+        <!-- Allow an optional m_ on private members -->
+        <module name="MemberName">
+            <property name="applyToPrivate" value="false" />
+            <property name="applyToPackage" value="false" />
+        </module>
+        <module name="MemberName">
+            <property name="format" value="^(m_)?[a-z][a-zA-Z0-9]*$" />
+            <property name="applyToPrivate" value="true" />
+            <property name="applyToPackage" value="true" />
+        </module>
+        <module name="MethodName" />
+        <module name="MethodTypeParameterName" />
+        <module name="PackageName">
+            <property name="format" value="^dan200\.computercraf(\.[a-z][a-z0-9]*)*" />
+        </module>
+        <module name="ParameterName" />
+        <module name="StaticVariableName">
+            <property name="format" value="^[a-z][a-zA-Z0-9]*|CAPABILITY(_[A-Z]+)?$" />
+            <property name="applyToPrivate" value="false" />
+        </module>
+        <module name="StaticVariableName">
+            <property name="format" value="^(s_)?[a-z][a-zA-Z0-9]*|CAPABILITY(_[A-Z]+)?$" />
+            <property name="applyToPrivate" value="true" />
+        </module>
+        <module name="TypeName" />
+
+        <!-- Whitespace -->
+        <module name="EmptyForInitializerPad"/>
+        <module name="EmptyForIteratorPad">
+            <property name="option" value="space"/>
+        </module>
+        <module name="GenericWhitespace" />
+        <module name="MethodParamPad" />
+        <module name="NoLineWrap" />
+        <module name="NoWhitespaceAfter">
+            <property name="tokens" value="AT,INC,DEC,UNARY_MINUS,UNARY_PLUS,BNOT,LNOT,DOT,ARRAY_DECLARATOR,INDEX_OP" />
+        </module>
+        <module name="NoWhitespaceBefore" />
+        <!-- TODO: Decide on an OperatorWrap style. -->
+        <module name="ParenPad">
+            <property name="option" value="space" />
+            <property name="tokens" value="ANNOTATION,ANNOTATION_FIELD_DEF,CTOR_CALL,CTOR_DEF,ENUM_CONSTANT_DEF,LITERAL_CATCH,LITERAL_DO,LITERAL_FOR,LITERAL_IF,LITERAL_NEW,LITERAL_SWITCH,LITERAL_SYNCHRONIZED,LITERAL_WHILE,METHOD_CALL,METHOD_DEF,RESOURCE_SPECIFICATION,SUPER_CTOR_CALL,LAMBDA" />
+        </module>
+        <module name="ParenPad">
+            <property name="option" value="nospace" />
+            <property name="tokens" value="DOT,EXPR,QUESTION" />
+        </module>
+        <module name="SeparatorWrap">
+            <property name="option" value="eol" />
+            <property name="tokens" value="COMMA,SEMI,ELLIPSIS,ARRAY_DECLARATOR,RBRACK,METHOD_REF" />
+        </module>
+        <module name="SeparatorWrap">
+            <property name="option" value="nl" />
+            <property name="tokens" value="DOT,AT" />
+        </module>
+        <module name="SingleSpaceSeparator" />
+        <module name="TypecastParenPad" />
+        <module name="WhitespaceAfter">
+            <property name="tokens" value="COMMA" />
+        </module>
+        <module name="WhitespaceAround">
+            <property name="allowEmptyConstructors" value="true" />
+            <property name="ignoreEnhancedForColon" value="false" />
+            <property name="tokens" value="ASSIGN,BAND,BAND_ASSIGN,BOR,BOR_ASSIGN,BSR,BSR_ASSIGN,BXOR,BXOR_ASSIGN,COLON,DIV,DIV_ASSIGN,DO_WHILE,EQUAL,GE,GT,LAMBDA,LAND,LCURLY,LE,LITERAL_RETURN,LOR,LT,MINUS,MINUS_ASSIGN,MOD,MOD_ASSIGN,NOT_EQUAL,PLUS,PLUS_ASSIGN,QUESTION,RCURLY,SL,SLIST,SL_ASSIGN,SR,SR_ASSIGN,STAR,STAR_ASSIGN,LITERAL_ASSERT,TYPE_EXTENSION_AND" />
+        </module>
+    </module>
+
+    <module name="FileTabCharacter" />
+    <module name="NewlineAtEndOfFile" />
+</module>
+

config/checkstyle/suppressions.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE suppressions PUBLIC
+    "-//Checkstyle//DTD SuppressionFilter Configuration 1.2//EN"
+    "https://checkstyle.org/dtds/suppressions_1_2.dtd">
+<suppressions>
+    <!-- Has a public m_label field. We need to check if this is used in other projects before renaming it. -->
+    <suppress checks="MemberName" files=".*[\\/]TileComputerBase.java"
+        message="Name 'm_label' must match pattern .*" />
+
+    <!-- All the config options and method fields. -->
+    <suppress checks="StaticVariableName" files=".*[\\/]ComputerCraft.java" />
+    <suppress checks="StaticVariableName" files=".*[\\/]ComputerCraftAPI.java" />
+</suppressions>

config/license/api.txt

@@ -0,0 +1,3 @@
+This file is part of the public ComputerCraft API - http://www.computercraft.info
+Copyright Daniel Ratcliffe, 2011-${year}. This API may be redistributed unmodified and in full only.
+For help using the API, and posting your mods, visit the forums at computercraft.info.

config/license/main.txt

@@ -0,0 +1,3 @@
+This file is part of ComputerCraft - http://www.computercraft.info
+Copyright Daniel Ratcliffe, 2011-${year}. Do not distribute without permission.
+Send enquiries to dratcliffe@gmail.com

gradle.properties

@@ -1,7 +1,7 @@
 # Mod properties
-mod_version=1.82.0
+mod_version=1.83.1
 
 # Minecraft properties
 mc_version=1.13.2
-forge_version=25.0.100
-mappings_version=20190327-1.13.2
+forge_version=25.0.219
+mappings_version=20190530-1.13.2

src/main/java/dan200/computercraft/ComputerCraftAPIImpl.java

@@ -43,6 +43,7 @@ public final class ComputerCraftAPIImpl implements IComputerCraftAPI
     {
     }
 
+    @Nonnull
     @Override
     public String getInstalledVersion()
     {
@@ -110,6 +111,7 @@ public final class ComputerCraftAPIImpl implements IComputerCraftAPI
         PocketUpgrades.register( upgrade );
     }
 
+    @Nonnull
     @Override
     public IPacketNetwork getWirelessNetwork()
     {
@@ -122,19 +124,18 @@ public final class ComputerCraftAPIImpl implements IComputerCraftAPI
         ApiFactories.register( factory );
     }
 
+    @Nonnull
     @Override
     public IWiredNode createWiredNodeForElement( @Nonnull IWiredElement element )
     {
         return new WiredNode( element );
     }
 
+    @Nonnull
     @Override
-    public IWiredElement getWiredElementAt( @Nonnull IBlockReader world, @Nonnull BlockPos pos, @Nonnull EnumFacing side )
+    public LazyOptional<IWiredElement> getWiredElementAt( @Nonnull IBlockReader world, @Nonnull BlockPos pos, @Nonnull EnumFacing side )
     {
         TileEntity tile = world.getTileEntity( pos );
-        if( tile == null ) return null;
-
-        LazyOptional<IWiredElement> element = tile.getCapability( CapabilityWiredElement.CAPABILITY, side );
-        return CapabilityWiredElement.unwrap( element );
+        return tile == null ? LazyOptional.empty() : tile.getCapability( CapabilityWiredElement.CAPABILITY, side );
     }
 }

src/main/java/dan200/computercraft/api/AbstractTurtleUpgrade.java

@@ -1,9 +1,8 @@
 /*
- * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
- * Send enquiries to dratcliffe@gmail.com
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
-
 package dan200.computercraft.api;
 
 import dan200.computercraft.api.turtle.ITurtleUpgrade;

src/main/java/dan200/computercraft/api/ComputerCraftAPI.java

@@ -24,6 +24,7 @@ import net.minecraft.util.EnumFacing;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.world.IBlockReader;
 import net.minecraft.world.World;
+import net.minecraftforge.common.util.LazyOptional;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -240,8 +241,8 @@ public final class ComputerCraftAPI
      * @return The element's node
      * @see IWiredElement#getNode()
      */
-    @Nullable
-    public static IWiredElement getWiredElementAt( @Nonnull IBlockReader world, @Nonnull BlockPos pos, @Nonnull EnumFacing side )
+    @Nonnull
+    public static LazyOptional<IWiredElement> getWiredElementAt( @Nonnull IBlockReader world, @Nonnull BlockPos pos, @Nonnull EnumFacing side )
     {
         return getInstance().getWiredElementAt( world, pos, side );
     }
@@ -266,12 +267,15 @@ public final class ComputerCraftAPI
 
     public interface IComputerCraftAPI
     {
+        @Nonnull
         String getInstalledVersion();
 
         int createUniqueNumberedSaveDir( @Nonnull World world, @Nonnull String parentSubPath );
 
+        @Nullable
         IWritableMount createSaveDirMount( @Nonnull World world, @Nonnull String subPath, long capacity );
 
+        @Nullable
         IMount createResourceMount( @Nonnull String domain, @Nonnull String subPath );
 
         void registerPeripheralProvider( @Nonnull IPeripheralProvider provider );
@@ -286,12 +290,15 @@ public final class ComputerCraftAPI
 
         void registerPocketUpgrade( @Nonnull IPocketUpgrade upgrade );
 
+        @Nonnull
         IPacketNetwork getWirelessNetwork();
 
         void registerAPIFactory( @Nonnull ILuaAPIFactory factory );
 
+        @Nonnull
         IWiredNode createWiredNodeForElement( @Nonnull IWiredElement element );
 
-        IWiredElement getWiredElementAt( @Nonnull IBlockReader world, @Nonnull BlockPos pos, @Nonnull EnumFacing side );
+        @Nonnull
+        LazyOptional<IWiredElement> getWiredElementAt( @Nonnull IBlockReader world, @Nonnull BlockPos pos, @Nonnull EnumFacing side );
     }
 }

src/main/java/dan200/computercraft/api/filesystem/FileOperationException.java

@@ -0,0 +1,41 @@
+/*
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
+ */
+package dan200.computercraft.api.filesystem;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * An {@link IOException} which occurred on a specific file.
+ *
+ * This may be thrown from a {@link IMount} or {@link IWritableMount} to give more information about a failure.
+ */
+public class FileOperationException extends IOException
+{
+    private static final long serialVersionUID = -8809108200853029849L;
+
+    private final String filename;
+
+    public FileOperationException( @Nullable String filename, @Nonnull String message )
+    {
+        super( Objects.requireNonNull( message, "message cannot be null" ) );
+        this.filename = filename;
+    }
+
+    public FileOperationException( String message )
+    {
+        super( Objects.requireNonNull( message, "message cannot be null" ) );
+        this.filename = null;
+    }
+
+    @Nullable
+    public String getFilename()
+    {
+        return filename;
+    }
+}

src/main/java/dan200/computercraft/api/filesystem/IMount.java

@@ -90,7 +90,6 @@ public interface IMount
      * @throws IOException If the file does not exist, or could not be opened.
      */
     @Nonnull
-    @SuppressWarnings( "deprecation" )
     default ReadableByteChannel openChannelForRead( @Nonnull String path ) throws IOException
     {
         return Channels.newChannel( openForRead( path ) );

src/main/java/dan200/computercraft/api/filesystem/IWritableMount.java

@@ -67,7 +67,6 @@ public interface IWritableMount extends IMount
      * @throws IOException If the file could not be opened for writing.
      */
     @Nonnull
-    @SuppressWarnings( "deprecation" )
     default WritableByteChannel openChannelForWrite( @Nonnull String path ) throws IOException
     {
         return Channels.newChannel( openForWrite( path ) );
@@ -94,7 +93,6 @@ public interface IWritableMount extends IMount
      * @throws IOException If the file could not be opened for writing.
      */
     @Nonnull
-    @SuppressWarnings( "deprecation" )
     default WritableByteChannel openChannelForAppend( @Nonnull String path ) throws IOException
     {
         return Channels.newChannel( openForAppend( path ) );

src/main/java/dan200/computercraft/api/peripheral/IWorkMonitor.java

@@ -1,9 +1,8 @@
 /*
- * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
- * Send enquiries to dratcliffe@gmail.com
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
-
 package dan200.computercraft.api.peripheral;
 
 import javax.annotation.Nonnull;

src/main/java/dan200/computercraft/api/pocket/AbstractPocketUpgrade.java

@@ -1,9 +1,8 @@
 /*
- * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
- * Send enquiries to dratcliffe@gmail.com
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
-
 package dan200.computercraft.api.pocket;
 
 import net.minecraft.item.ItemStack;

src/main/java/dan200/computercraft/api/turtle/event/TurtleInspectItemEvent.java

@@ -1,9 +1,8 @@
 /*
- * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
- * Send enquiries to dratcliffe@gmail.com
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
-
 package dan200.computercraft.api.turtle.event;
 
 import dan200.computercraft.api.lua.ILuaContext;

src/main/java/dan200/computercraft/api/turtle/event/TurtleRefuelEvent.java

@@ -1,9 +1,8 @@
 /*
- * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
- * Send enquiries to dratcliffe@gmail.com
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2019. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
  */
-
 package dan200.computercraft.api.turtle.event;
 
 import dan200.computercraft.api.turtle.ITurtleAccess;

src/main/java/dan200/computercraft/client/ClientRegistry.java

@@ -121,6 +121,12 @@ public final class ClientRegistry
     @SubscribeEvent
     public static void onItemColours( ColorHandlerEvent.Item event )
     {
+        if( ComputerCraft.Items.disk == null || ComputerCraft.Blocks.turtleNormal == null )
+        {
+            ComputerCraft.log.warn( "Block/item registration has failed. Skipping registration of item colours." );
+            return;
+        }
+
         event.getItemColors().register(
             ( stack, layer ) -> layer == 1 ? ((ItemDisk) stack.getItem()).getColour( stack ) : 0xFFFFFF,
             ComputerCraft.Items.disk

src/main/java/dan200/computercraft/client/gui/GuiComputer.java

@@ -20,9 +20,10 @@ import net.minecraft.util.ResourceLocation;
 
 public class GuiComputer extends GuiContainer
 {
-    private static final ResourceLocation BACKGROUND_NORMAL = new ResourceLocation( "computercraft", "textures/gui/corners_normal.png" );
-    private static final ResourceLocation BACKGROUND_ADVANCED = new ResourceLocation( "computercraft", "textures/gui/corners_advanced.png" );
-    private static final ResourceLocation BACKGROUND_COMMAND = new ResourceLocation( "computercraft", "textures/gui/corners_command.png" );
+    public static final ResourceLocation BACKGROUND_NORMAL = new ResourceLocation( ComputerCraft.MOD_ID, "textures/gui/corners_normal.png" );
+    public static final ResourceLocation BACKGROUND_ADVANCED = new ResourceLocation( ComputerCraft.MOD_ID, "textures/gui/corners_advanced.png" );
+    public static final ResourceLocation BACKGROUND_COMMAND = new ResourceLocation( ComputerCraft.MOD_ID, "textures/gui/corners_command.png" );
+    public static final ResourceLocation BACKGROUND_COLOUR = new ResourceLocation( ComputerCraft.MOD_ID, "textures/gui/corners_colour.png" );
 
     private final ComputerFamily m_family;
     private final ClientComputer m_computer;
@@ -118,12 +119,12 @@ public class GuiComputer extends GuiContainer
         }
 
         drawTexturedModalRect( startX - 12, startY - 12, 12, 28, 12, 12 );
-        drawTexturedModalRect( startX - 12, endY, 12, 40, 12, 16 );
+        drawTexturedModalRect( startX - 12, endY, 12, 40, 12, 12 );
         drawTexturedModalRect( endX, startY - 12, 24, 28, 12, 12 );
-        drawTexturedModalRect( endX, endY, 24, 40, 12, 16 );
+        drawTexturedModalRect( endX, endY, 24, 40, 12, 12 );
 
         drawTexturedModalRect( startX, startY - 12, 0, 0, endX - startX, 12 );
-        drawTexturedModalRect( startX, endY, 0, 12, endX - startX, 16 );
+        drawTexturedModalRect( startX, endY, 0, 12, endX - startX, 12 );
 
         drawTexturedModalRect( startX - 12, startY, 0, 28, 12, endY - startY );
         drawTexturedModalRect( endX, startY, 36, 28, 12, endY - startY );

src/main/java/dan200/computercraft/client/gui/GuiTurtle.java

@@ -88,7 +88,7 @@ public class GuiTurtle extends GuiContainer
             int slotX = slot % 4;
             int slotY = slot / 4;
             mc.getTextureManager().bindTexture( advanced ? BACKGROUND_ADVANCED : BACKGROUND_NORMAL );
-            drawTexturedModalRect( guiLeft + m_container.m_turtleInvStartX - 2 + slotX * 18, guiTop + m_container.m_playerInvStartY - 2 + slotY * 18, 0, 217, 24, 24 );
+            drawTexturedModalRect( guiLeft + m_container.turtleInvStartX - 2 + slotX * 18, guiTop + m_container.playerInvStartY - 2 + slotY * 18, 0, 217, 24, 24 );
         }
     }
 

src/main/java/dan200/computercraft/client/proxy/ComputerCraftProxyClient.java

@@ -75,8 +75,9 @@ public final class ComputerCraftProxyClient
         ModLoadingContext.get().registerExtensionPoint( ExtensionPoint.GUIFACTORY, () -> packet -> {
             ContainerType<?> type = ContainerType.factories.get( packet.getId() ).get();
             if( packet.getAdditionalData() != null ) type.fromBytes( packet.getAdditionalData() );
-            return ((BiFunction<ContainerType<?>, EntityPlayer, GuiContainer>) ContainerType.guiFactories.get( packet.getId() ))
-                .apply( type, Minecraft.getInstance().player );
+            @SuppressWarnings( "unchecked" )
+            BiFunction<ContainerType<?>, EntityPlayer, GuiContainer> factory = (BiFunction<ContainerType<?>, EntityPlayer, GuiContainer>) ContainerType.guiFactories.get( packet.getId() );
+            return factory.apply( type, Minecraft.getInstance().player );
         } );
     }
 

src/main/java/dan200/computercraft/client/render/CableHighlightRenderer.java

@@ -26,9 +26,9 @@ import net.minecraftforge.fml.common.Mod;
 import org.lwjgl.opengl.GL11;
 
 @Mod.EventBusSubscriber( modid = ComputerCraft.MOD_ID, value = Dist.CLIENT )
-public final class RenderOverlayCable
+public final class CableHighlightRenderer
 {
-    private RenderOverlayCable()
+    private CableHighlightRenderer()
     {
     }
 
@@ -74,7 +74,8 @@ public final class RenderOverlayCable
         double z = player.lastTickPosZ + (player.posZ - player.lastTickPosZ) * partialTicks;
 
         VoxelShape shape = WorldUtil.isVecInside( CableShapes.getModemShape( state ), event.getTarget().hitVec.subtract( pos.getX(), pos.getY(), pos.getZ() ) )
-            ? CableShapes.getModemShape( state ) : CableShapes.getCableShape( state );
+            ? CableShapes.getModemShape( state )
+            : CableShapes.getCableShape( state );
 
         WorldRenderer.drawShape( shape, pos.getX() - x, pos.getY() - y, pos.getZ() - z, 0.0F, 0.0F, 0.0F, 0.4F );
 

src/main/java/dan200/computercraft/client/render/ItemPocketRenderer.java

@@ -12,25 +12,24 @@ import dan200.computercraft.client.gui.FixedWidthFontRenderer;
 import dan200.computercraft.core.terminal.Terminal;
 import dan200.computercraft.core.terminal.TextBuffer;
 import dan200.computercraft.shared.computer.core.ClientComputer;
+import dan200.computercraft.shared.computer.core.ComputerFamily;
 import dan200.computercraft.shared.pocket.items.ItemPocketComputer;
+import dan200.computercraft.shared.util.Colour;
 import dan200.computercraft.shared.util.Palette;
 import net.minecraft.client.Minecraft;
+import net.minecraft.client.renderer.BufferBuilder;
 import net.minecraft.client.renderer.GlStateManager;
-import net.minecraft.client.renderer.ItemRenderer;
-import net.minecraft.client.renderer.model.IBakedModel;
-import net.minecraft.client.renderer.model.ItemCameraTransforms.TransformType;
-import net.minecraft.client.renderer.texture.TextureManager;
-import net.minecraft.client.renderer.texture.TextureMap;
+import net.minecraft.client.renderer.Tessellator;
+import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
 import net.minecraft.item.ItemStack;
 import net.minecraftforge.api.distmarker.Dist;
-import net.minecraftforge.client.ForgeHooksClient;
 import net.minecraftforge.client.event.RenderSpecificHandEvent;
 import net.minecraftforge.eventbus.api.SubscribeEvent;
 import net.minecraftforge.fml.common.Mod;
 import org.lwjgl.opengl.GL11;
 
-import static dan200.computercraft.client.gui.FixedWidthFontRenderer.FONT_HEIGHT;
-import static dan200.computercraft.client.gui.FixedWidthFontRenderer.FONT_WIDTH;
+import static dan200.computercraft.client.gui.FixedWidthFontRenderer.*;
+import static dan200.computercraft.client.gui.GuiComputer.*;
 
 /**
  * Emulates map rendering for pocket computers
@@ -38,6 +37,10 @@ import static dan200.computercraft.client.gui.FixedWidthFontRenderer.FONT_WIDTH;
 @Mod.EventBusSubscriber( modid = ComputerCraft.MOD_ID, value = Dist.CLIENT )
 public final class ItemPocketRenderer extends ItemMapLikeRenderer
 {
+    private static final int MARGIN = 2;
+    private static final int FRAME = 12;
+    private static final int LIGHT_HEIGHT = 8;
+
     private static final ItemPocketRenderer INSTANCE = new ItemPocketRenderer();
 
     private ItemPocketRenderer()
@@ -57,115 +60,195 @@ public final class ItemPocketRenderer extends ItemMapLikeRenderer
     @Override
     protected void renderItem( ItemStack stack )
     {
+        ClientComputer computer = ItemPocketComputer.createClientComputer( stack );
+        Terminal terminal = computer == null ? null : computer.getTerminal();
+
+        int termWidth, termHeight;
+        if( terminal == null )
+        {
+            termWidth = ComputerCraft.terminalWidth_pocketComputer;
+            termHeight = ComputerCraft.terminalHeight_pocketComputer;
+        }
+        else
+        {
+            termWidth = terminal.getWidth();
+            termHeight = terminal.getHeight();
+        }
+
+        int width = termWidth * FONT_WIDTH + MARGIN * 2;
+        int height = termHeight * FONT_HEIGHT + MARGIN * 2;
+
         // Setup various transformations. Note that these are partially adapted from the corresponding method
         // in ItemRenderer
+        GlStateManager.pushMatrix();
+
         GlStateManager.disableLighting();
+        GlStateManager.disableDepthTest();
 
         GlStateManager.rotatef( 180f, 0f, 1f, 0f );
         GlStateManager.rotatef( 180f, 0f, 0f, 1f );
         GlStateManager.scalef( 0.5f, 0.5f, 0.5f );
 
-        ClientComputer computer = ItemPocketComputer.createClientComputer( stack );
+        double scale = 0.75 / Math.max( width + FRAME * 2, height + FRAME * 2 + LIGHT_HEIGHT );
+        GlStateManager.scaled( scale, scale, 0 );
+        GlStateManager.translated( -0.5 * width, -0.5 * height, 0 );
 
+        // Render the main frame
+        ItemPocketComputer item = (ItemPocketComputer) stack.getItem();
+        ComputerFamily family = item.getFamily();
+        int frameColour = item.getColour( stack );
+        renderFrame( family, frameColour, width, height );
+
+        // Render the light
+        int lightColour = ItemPocketComputer.getLightState( stack );
+        if( lightColour == -1 ) lightColour = Colour.Black.getHex();
+        renderLight( lightColour, width, height );
+
+        if( computer != null && terminal != null )
         {
-            // First render the background item. We use the item's model rather than a direct texture as this ensures
-            // we display the pocket light and other such decorations.
-            GlStateManager.pushMatrix();
+            // If we've a computer and terminal then attempt to render it.
+            renderTerminal( terminal, !computer.isColour(), width, height );
+        }
+        else
+        {
+            // Otherwise render a plain background
+            Minecraft.getInstance().getTextureManager().bindTexture( BACKGROUND );
 
-            GlStateManager.scalef( 1.0f, -1.0f, 1.0f );
+            Tessellator tessellator = Tessellator.getInstance();
+            BufferBuilder buffer = tessellator.getBuffer();
 
-            Minecraft minecraft = Minecraft.getInstance();
-            TextureManager textureManager = minecraft.getTextureManager();
-            ItemRenderer renderItem = minecraft.getItemRenderer();
-
-            // Copy of RenderItem#renderItemModelIntoGUI but without the translation or scaling
-            textureManager.bindTexture( TextureMap.LOCATION_BLOCKS_TEXTURE );
-            textureManager.getTexture( TextureMap.LOCATION_BLOCKS_TEXTURE ).setBlurMipmap( false, false );
-
-            GlStateManager.enableRescaleNormal();
-            GlStateManager.enableAlphaTest();
-            GlStateManager.alphaFunc( GL11.GL_GREATER, 0.1F );
-            GlStateManager.enableBlend();
-            GlStateManager.blendFunc( GlStateManager.SourceFactor.SRC_ALPHA, GlStateManager.DestFactor.ONE_MINUS_SRC_ALPHA );
-            GlStateManager.color4f( 1.0F, 1.0F, 1.0F, 1.0F );
-
-            IBakedModel baked = renderItem.getItemModelWithOverrides( stack, null, null );
-            baked = ForgeHooksClient.handleCameraTransforms( baked, TransformType.GUI, false );
-            renderItem.renderItem( stack, baked );
-
-            GlStateManager.disableAlphaTest();
-            GlStateManager.disableRescaleNormal();
-
-            GlStateManager.popMatrix();
+            Colour black = Colour.Black;
+            buffer.begin( GL11.GL_QUADS, DefaultVertexFormats.POSITION );
+            renderTexture( buffer, 0, 0, 0, 0, width, height, black.getR(), black.getG(), black.getB() );
+            tessellator.draw();
         }
 
-        // If we've a computer and terminal then attempt to render it.
-        if( computer != null )
+        GlStateManager.enableDepthTest();
+        GlStateManager.enableLighting();
+        GlStateManager.popMatrix();
+    }
+
+    private static void renderFrame( ComputerFamily family, int colour, int width, int height )
+    {
+
+        Minecraft.getInstance().getTextureManager().bindTexture( colour != -1
+            ? BACKGROUND_COLOUR
+            : family == ComputerFamily.Normal ? BACKGROUND_NORMAL : BACKGROUND_ADVANCED
+        );
+
+        float r = ((colour >>> 16) & 0xFF) / 255.0f;
+        float g = ((colour >>> 8) & 0xFF) / 255.0f;
+        float b = (colour & 0xFF) / 255.0f;
+
+        Tessellator tessellator = Tessellator.getInstance();
+        BufferBuilder buffer = tessellator.getBuffer();
+        buffer.begin( GL11.GL_QUADS, DefaultVertexFormats.POSITION_TEX_COLOR );
+
+        // Top left, middle, right
+        renderTexture( buffer, -FRAME, -FRAME, 12, 28, FRAME, FRAME, r, g, b );
+        renderTexture( buffer, 0, -FRAME, 0, 0, width, FRAME, r, g, b );
+        renderTexture( buffer, width, -FRAME, 24, 28, FRAME, FRAME, r, g, b );
+
+        // Left and bright border
+        renderTexture( buffer, -FRAME, 0, 0, 28, FRAME, height, r, g, b );
+        renderTexture( buffer, width, 0, 36, 28, FRAME, height, r, g, b );
+
+        // Bottom left, middle, right. We do this in three portions: the top inner corners, an extended region for
+        // lights, and then the bottom outer corners.
+        renderTexture( buffer, -FRAME, height, 12, 40, FRAME, FRAME / 2, r, g, b );
+        renderTexture( buffer, 0, height, 0, 12, width, FRAME / 2, r, g, b );
+        renderTexture( buffer, width, height, 24, 40, FRAME, FRAME / 2, r, g, b );
+
+        renderTexture( buffer, -FRAME, height + FRAME / 2, 12, 44, FRAME, LIGHT_HEIGHT, FRAME, 4, r, g, b );
+        renderTexture( buffer, 0, height + FRAME / 2, 0, 16, width, LIGHT_HEIGHT, FRAME, 4, r, g, b );
+        renderTexture( buffer, width, height + FRAME / 2, 24, 44, FRAME, LIGHT_HEIGHT, FRAME, 4, r, g, b );
+
+        renderTexture( buffer, -FRAME, height + LIGHT_HEIGHT + FRAME / 2, 12, 40 + FRAME / 2, FRAME, FRAME / 2, r, g, b );
+        renderTexture( buffer, 0, height + LIGHT_HEIGHT + FRAME / 2, 0, 12 + FRAME / 2, width, FRAME / 2, r, g, b );
+        renderTexture( buffer, width, height + LIGHT_HEIGHT + FRAME / 2, 24, 40 + FRAME / 2, FRAME, FRAME / 2, r, g, b );
+
+        tessellator.draw();
+    }
+
+    private static void renderLight( int colour, int width, int height )
+    {
+        GlStateManager.enableBlend();
+        GlStateManager.disableTexture2D();
+
+        float r = ((colour >>> 16) & 0xFF) / 255.0f;
+        float g = ((colour >>> 8) & 0xFF) / 255.0f;
+        float b = (colour & 0xFF) / 255.0f;
+
+        Tessellator tessellator = Tessellator.getInstance();
+        BufferBuilder buffer = tessellator.getBuffer();
+        buffer.begin( GL11.GL_QUADS, DefaultVertexFormats.POSITION_COLOR );
+        buffer.pos( width - LIGHT_HEIGHT * 2, height + LIGHT_HEIGHT + FRAME / 2.0f, 0.0D ).color( r, g, b, 1.0f ).endVertex();
+        buffer.pos( width, height + LIGHT_HEIGHT + FRAME / 2.0f, 0.0D ).color( r, g, b, 1.0f ).endVertex();
+        buffer.pos( width, height + FRAME / 2.0f, 0.0D ).color( r, g, b, 1.0f ).endVertex();
+        buffer.pos( width - LIGHT_HEIGHT * 2, height + FRAME / 2.0f, 0.0D ).color( r, g, b, 1.0f ).endVertex();
+
+        tessellator.draw();
+        GlStateManager.enableTexture2D();
+    }
+
+    private static void renderTerminal( Terminal terminal, boolean greyscale, int width, int height )
+    {
+        synchronized( terminal )
         {
-            Terminal terminal = computer.getTerminal();
-            if( terminal != null )
+            int termWidth = terminal.getWidth();
+            int termHeight = terminal.getHeight();
+
+            FixedWidthFontRenderer fontRenderer = FixedWidthFontRenderer.instance();
+            Palette palette = terminal.getPalette();
+
+            // Render top/bottom borders
+            TextBuffer emptyLine = new TextBuffer( ' ', termWidth );
+            fontRenderer.drawString(
+                emptyLine, MARGIN, 0,
+                terminal.getTextColourLine( 0 ), terminal.getBackgroundColourLine( 0 ), MARGIN, MARGIN, greyscale, palette
+            );
+            fontRenderer.drawString(
+                emptyLine, MARGIN, 2 * MARGIN + (termHeight - 1) * FixedWidthFontRenderer.FONT_HEIGHT,
+                terminal.getTextColourLine( termHeight - 1 ), terminal.getBackgroundColourLine( termHeight - 1 ), MARGIN, MARGIN, greyscale, palette
+            );
+
+            // Render the actual text
+            for( int line = 0; line < termWidth; line++ )
             {
-                synchronized( terminal )
-                {
-                    GlStateManager.pushMatrix();
-                    GlStateManager.disableDepthTest();
+                TextBuffer text = terminal.getLine( line );
+                TextBuffer colour = terminal.getTextColourLine( line );
+                TextBuffer backgroundColour = terminal.getBackgroundColourLine( line );
+                fontRenderer.drawString(
+                    text, MARGIN, MARGIN + line * FONT_HEIGHT,
+                    colour, backgroundColour, MARGIN, MARGIN, greyscale, palette
+                );
+            }
 
-                    // Reset the position to be at the top left corner of the pocket computer
-                    // Note we translate towards the screen slightly too.
-                    GlStateManager.translated( -8 / 16.0, -8 / 16.0, 0.5 / 16.0 );
-                    // Translate to the top left of the screen.
-                    GlStateManager.translated( 4 / 16.0, 3 / 16.0, 0 );
-
-                    // Work out the scaling required to resize the terminal in order to fit on the computer
-                    final int margin = 2;
-                    int tw = terminal.getWidth();
-                    int th = terminal.getHeight();
-                    int width = tw * FONT_WIDTH + margin * 2;
-                    int height = th * FONT_HEIGHT + margin * 2;
-                    int max = Math.max( height, width );
-
-                    // The grid is 8 * 8 wide, so we start with a base of 1/2 (8 / 16).
-                    double scale = 1.0 / 2.0 / max;
-                    GlStateManager.scaled( scale, scale, scale );
-
-                    // The margin/start positions are determined in order for the terminal to be centred.
-                    int startX = (max - width) / 2 + margin;
-                    int startY = (max - height) / 2 + margin;
-
-                    FixedWidthFontRenderer fontRenderer = FixedWidthFontRenderer.instance();
-                    boolean greyscale = !computer.isColour();
-                    Palette palette = terminal.getPalette();
-
-                    // Render the actual text
-                    for( int line = 0; line < th; line++ )
-                    {
-                        TextBuffer text = terminal.getLine( line );
-                        TextBuffer colour = terminal.getTextColourLine( line );
-                        TextBuffer backgroundColour = terminal.getBackgroundColourLine( line );
-                        fontRenderer.drawString(
-                            text, startX, startY + line * FONT_HEIGHT,
-                            colour, backgroundColour, margin, margin, greyscale, palette
-                        );
-                    }
-
-                    // And render the cursor;
-                    int tx = terminal.getCursorX(), ty = terminal.getCursorY();
-                    if( terminal.getCursorBlink() && FrameInfo.getGlobalCursorBlink() &&
-                        tx >= 0 && ty >= 0 && tx < tw && ty < th )
-                    {
-                        TextBuffer cursorColour = new TextBuffer( "0123456789abcdef".charAt( terminal.getTextColour() ), 1 );
-                        fontRenderer.drawString(
-                            new TextBuffer( '_', 1 ), startX + FONT_WIDTH * tx, startY + FONT_HEIGHT * ty,
-                            cursorColour, null, 0, 0, greyscale, palette
-                        );
-                    }
-
-                    GlStateManager.enableDepthTest();
-                    GlStateManager.popMatrix();
-                }
+            // And render the cursor;
+            int tx = terminal.getCursorX(), ty = terminal.getCursorY();
+            if( terminal.getCursorBlink() && FrameInfo.getGlobalCursorBlink() &&
+                tx >= 0 && ty >= 0 && tx < termWidth && ty < termHeight )
+            {
+                TextBuffer cursorColour = new TextBuffer( "0123456789abcdef".charAt( terminal.getTextColour() ), 1 );
+                fontRenderer.drawString(
+                    new TextBuffer( '_', 1 ), MARGIN + FONT_WIDTH * tx, MARGIN + FONT_HEIGHT * ty,
+                    cursorColour, null, 0, 0, greyscale, palette
+                );
             }
         }
+    }
 
-        GlStateManager.enableLighting();
+    private static void renderTexture( BufferBuilder builder, int x, int y, int textureX, int textureY, int width, int height, float r, float g, float b )
+    {
+        renderTexture( builder, x, y, textureX, textureY, width, height, width, height, r, g, b );
+    }
+
+    private static void renderTexture( BufferBuilder builder, int x, int y, int textureX, int textureY, int width, int height, int textureWidth, int textureHeight, float r, float g, float b )
+    {
+        float scale = 1 / 255.0f;
+        builder.pos( x, y + height, 0 ).tex( textureX * scale, (textureY + textureHeight) * scale ).color( r, g, b, 1.0f ).endVertex();
+        builder.pos( x + width, y + height, 0 ).tex( (textureX + textureWidth) * scale, (textureY + textureHeight) * scale ).color( r, g, b, 1.0f ).endVertex();
+        builder.pos( x + width, y, 0 ).tex( (textureX + textureWidth) * scale, textureY * scale ).color( r, g, b, 1.0f ).endVertex();
+        builder.pos( x, y, 0 ).tex( textureX * scale, textureY * scale ).color( r, g, b, 1.0f ).endVertex();
     }
 }

src/main/java/dan200/computercraft/client/render/ModelTransformer.java

@@ -94,7 +94,7 @@ public final class ModelTransformer
         private final Point3f[] before = new Point3f[4];
         private final Point3f[] after = new Point3f[4];
 
-        public NormalAwareTransformer( IVertexConsumer parent, Matrix4f positionMatrix, Matrix4f normalMatrix )
+        NormalAwareTransformer( IVertexConsumer parent, Matrix4f positionMatrix, Matrix4f normalMatrix )
         {
             super( parent );
             this.positionMatrix = positionMatrix;

src/main/java/dan200/computercraft/client/render/MonitorHighlightRenderer.java

@@ -0,0 +1,117 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+
+package dan200.computercraft.client.render;
+
+import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.shared.peripheral.monitor.TileMonitor;
+import net.minecraft.client.Minecraft;
+import net.minecraft.client.renderer.BufferBuilder;
+import net.minecraft.client.renderer.GlStateManager;
+import net.minecraft.client.renderer.Tessellator;
+import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
+import net.minecraft.entity.player.EntityPlayer;
+import net.minecraft.tileentity.TileEntity;
+import net.minecraft.util.EnumFacing;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.RayTraceResult;
+import net.minecraft.world.World;
+import net.minecraftforge.api.distmarker.Dist;
+import net.minecraftforge.client.event.DrawBlockHighlightEvent;
+import net.minecraftforge.eventbus.api.SubscribeEvent;
+import net.minecraftforge.fml.common.Mod;
+import org.lwjgl.opengl.GL11;
+
+import java.util.EnumSet;
+
+import static net.minecraft.util.EnumFacing.*;
+
+@Mod.EventBusSubscriber( modid = ComputerCraft.MOD_ID, value = Dist.CLIENT )
+public final class MonitorHighlightRenderer
+{
+    private static final float EXPAND = 0.002f;
+
+    private MonitorHighlightRenderer()
+    {
+    }
+
+    @SubscribeEvent
+    public static void drawHighlight( DrawBlockHighlightEvent event )
+    {
+        if( event.getTarget().type != RayTraceResult.Type.BLOCK || event.getPlayer().isSneaking() ) return;
+
+        World world = event.getPlayer().getEntityWorld();
+        BlockPos pos = event.getTarget().getBlockPos();
+
+        TileEntity tile = world.getTileEntity( pos );
+        if( !(tile instanceof TileMonitor) ) return;
+
+        TileMonitor monitor = (TileMonitor) tile;
+        event.setCanceled( true );
+
+        // Determine which sides are part of the external faces of the monitor, and so which need to be rendered.
+        EnumSet<EnumFacing> faces = EnumSet.allOf( EnumFacing.class );
+        EnumFacing front = monitor.getFront();
+        faces.remove( front );
+        if( monitor.getXIndex() != 0 ) faces.remove( monitor.getRight().getOpposite() );
+        if( monitor.getXIndex() != monitor.getWidth() - 1 ) faces.remove( monitor.getRight() );
+        if( monitor.getYIndex() != 0 ) faces.remove( monitor.getDown().getOpposite() );
+        if( monitor.getYIndex() != monitor.getHeight() - 1 ) faces.remove( monitor.getDown() );
+
+        GlStateManager.enableBlend();
+        GlStateManager.blendFuncSeparate( GlStateManager.SourceFactor.SRC_ALPHA, GlStateManager.DestFactor.ONE_MINUS_SRC_ALPHA, GlStateManager.SourceFactor.ONE, GlStateManager.DestFactor.ZERO );
+        GlStateManager.lineWidth( Math.max( 2.5F, (float) Minecraft.getInstance().mainWindow.getFramebufferWidth() / 1920.0F * 2.5F ) );
+        GlStateManager.disableTexture2D();
+        GlStateManager.depthMask( false );
+        GlStateManager.pushMatrix();
+
+        EntityPlayer player = event.getPlayer();
+        double x = player.lastTickPosX + (player.posX - player.lastTickPosX) * event.getPartialTicks();
+        double y = player.lastTickPosY + (player.posY - player.lastTickPosY) * event.getPartialTicks();
+        double z = player.lastTickPosZ + (player.posZ - player.lastTickPosZ) * event.getPartialTicks();
+
+        GlStateManager.translated( -x + pos.getX(), -y + pos.getY(), -z + pos.getZ() );
+
+        Tessellator tessellator = Tessellator.getInstance();
+        BufferBuilder buffer = tessellator.getBuffer();
+        buffer.begin( GL11.GL_LINES, DefaultVertexFormats.POSITION_COLOR );
+
+        // I wish I could think of a better way to do this
+        if( faces.contains( NORTH ) || faces.contains( WEST ) ) line( buffer, 0, 0, 0, UP );
+        if( faces.contains( SOUTH ) || faces.contains( WEST ) ) line( buffer, 0, 0, 1, UP );
+        if( faces.contains( NORTH ) || faces.contains( EAST ) ) line( buffer, 1, 0, 0, UP );
+        if( faces.contains( SOUTH ) || faces.contains( EAST ) ) line( buffer, 1, 0, 1, UP );
+        if( faces.contains( NORTH ) || faces.contains( DOWN ) ) line( buffer, 0, 0, 0, EAST );
+        if( faces.contains( SOUTH ) || faces.contains( DOWN ) ) line( buffer, 0, 0, 1, EAST );
+        if( faces.contains( NORTH ) || faces.contains( UP ) ) line( buffer, 0, 1, 0, EAST );
+        if( faces.contains( SOUTH ) || faces.contains( UP ) ) line( buffer, 0, 1, 1, EAST );
+        if( faces.contains( WEST ) || faces.contains( DOWN ) ) line( buffer, 0, 0, 0, SOUTH );
+        if( faces.contains( EAST ) || faces.contains( DOWN ) ) line( buffer, 1, 0, 0, SOUTH );
+        if( faces.contains( WEST ) || faces.contains( UP ) ) line( buffer, 0, 1, 0, SOUTH );
+        if( faces.contains( EAST ) || faces.contains( UP ) ) line( buffer, 1, 1, 0, SOUTH );
+
+        tessellator.draw();
+
+        GlStateManager.popMatrix();
+        GlStateManager.depthMask( true );
+        GlStateManager.enableTexture2D();
+        GlStateManager.disableBlend();
+    }
+
+    private static void line( BufferBuilder buffer, int x, int y, int z, EnumFacing direction )
+    {
+        double minX = x == 0 ? -EXPAND : 1 + EXPAND;
+        double minY = y == 0 ? -EXPAND : 1 + EXPAND;
+        double minZ = z == 0 ? -EXPAND : 1 + EXPAND;
+
+        buffer.pos( minX, minY, minZ ).color( 0, 0, 0, 0.4f ).endVertex();
+        buffer.pos(
+            minX + direction.getXOffset() * (1 + EXPAND * 2),
+            minY + direction.getYOffset() * (1 + EXPAND * 2),
+            minZ + direction.getZOffset() * (1 + EXPAND * 2)
+        ).color( 0, 0, 0, 0.4f ).endVertex();
+    }
+}

src/main/java/dan200/computercraft/client/render/TileEntityCableRenderer.java

@@ -11,6 +11,7 @@ import dan200.computercraft.shared.peripheral.modem.wired.BlockCable;
 import dan200.computercraft.shared.peripheral.modem.wired.CableModemVariant;
 import dan200.computercraft.shared.peripheral.modem.wired.CableShapes;
 import dan200.computercraft.shared.peripheral.modem.wired.TileCable;
+import dan200.computercraft.shared.util.WorldUtil;
 import net.minecraft.block.Block;
 import net.minecraft.block.state.IBlockState;
 import net.minecraft.client.Minecraft;
@@ -25,10 +26,10 @@ import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
 import net.minecraft.util.BlockRenderLayer;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.RayTraceResult;
-import net.minecraft.util.math.shapes.VoxelShape;
 import net.minecraft.world.World;
 import net.minecraftforge.client.ForgeHooksClient;
 import net.minecraftforge.client.MinecraftForgeClient;
+import net.minecraftforge.client.model.data.EmptyModelData;
 import org.lwjgl.opengl.GL11;
 
 import javax.annotation.Nonnull;
@@ -60,8 +61,7 @@ public class TileEntityCableRenderer extends TileEntityRenderer<TileCable>
         Block block = state.getBlock();
         if( block != ComputerCraft.Blocks.cable ) return;
 
-        VoxelShape shape = CableShapes.getModemShape( state );
-        state = te.hasModem() && shape.getBoundingBox().grow( 0.02, 0.02, 0.02 ).contains( hit.hitVec.subtract( pos.getX(), pos.getY(), pos.getZ() ) )
+        state = WorldUtil.isVecInside( CableShapes.getModemShape( state ), hit.hitVec.subtract( pos.getX(), pos.getY(), pos.getZ() ) )
             ? block.getDefaultState().with( BlockCable.MODEM, state.get( BlockCable.MODEM ) )
             : state.with( BlockCable.MODEM, CableModemVariant.None );
 
@@ -81,7 +81,7 @@ public class TileEntityCableRenderer extends TileEntityRenderer<TileCable>
         mc.getBlockRendererDispatcher().getBlockModelRenderer().renderModel(
             world,
             ForgeHooksClient.getDamageModel( model, breakingTexture, state, world, pos ),
-            state, pos, buffer, true, random, state.getPositionRandom( pos )
+            state, pos, buffer, true, random, state.getPositionRandom( pos ), EmptyModelData.INSTANCE
         );
 
         ForgeHooksClient.setRenderLayer( BlockRenderLayer.SOLID );

src/main/java/dan200/computercraft/client/render/TileEntityTurtleRenderer.java

@@ -31,6 +31,7 @@ import net.minecraft.util.EnumFacing;
 import net.minecraft.util.ResourceLocation;
 import net.minecraft.util.math.Vec3d;
 import net.minecraftforge.client.ForgeHooksClient;
+import net.minecraftforge.client.model.data.EmptyModelData;
 import net.minecraftforge.client.model.pipeline.LightUtil;
 import org.apache.commons.lang3.tuple.Pair;
 import org.lwjgl.opengl.GL11;
@@ -197,10 +198,10 @@ public class TileEntityTurtleRenderer extends TileEntityRenderer<TileTurtle>
         Random random = new Random( 0 );
         Tessellator tessellator = Tessellator.getInstance();
         rendererDispatcher.textureManager.bindTexture( TextureMap.LOCATION_BLOCKS_TEXTURE );
-        renderQuads( tessellator, model.getQuads( state, null, random ), tints );
+        renderQuads( tessellator, model.getQuads( state, null, random, EmptyModelData.INSTANCE ), tints );
         for( EnumFacing facing : DirectionUtil.FACINGS )
         {
-            renderQuads( tessellator, model.getQuads( state, facing, random ), tints );
+            renderQuads( tessellator, model.getQuads( state, facing, random, EmptyModelData.INSTANCE ), tints );
         }
     }
 

src/main/java/dan200/computercraft/client/render/TurtleModelLoader.java

@@ -70,7 +70,10 @@ public final class TurtleModelLoader implements ICustomModelLoader
     {
         private final ResourceLocation family;
 
-        private TurtleModel( ResourceLocation family ) {this.family = family;}
+        private TurtleModel( ResourceLocation family )
+        {
+            this.family = family;
+        }
 
         @Nonnull
         @Override

src/main/java/dan200/computercraft/client/render/TurtleMultiModel.java

@@ -9,10 +9,11 @@ package dan200.computercraft.client.render;
 import net.minecraft.block.state.IBlockState;
 import net.minecraft.client.renderer.model.BakedQuad;
 import net.minecraft.client.renderer.model.IBakedModel;
-import net.minecraft.client.renderer.model.ItemCameraTransforms;
 import net.minecraft.client.renderer.model.ItemOverrideList;
 import net.minecraft.client.renderer.texture.TextureAtlasSprite;
 import net.minecraft.util.EnumFacing;
+import net.minecraftforge.client.model.data.EmptyModelData;
+import net.minecraftforge.client.model.data.IModelData;
 
 import javax.annotation.Nonnull;
 import javax.vecmath.Matrix4f;
@@ -44,7 +45,15 @@ public class TurtleMultiModel implements IBakedModel
 
     @Nonnull
     @Override
+    @Deprecated
     public List<BakedQuad> getQuads( IBlockState state, EnumFacing side, @Nonnull Random rand )
+    {
+        return getQuads( state, side, rand, EmptyModelData.INSTANCE );
+    }
+
+    @Nonnull
+    @Override
+    public List<BakedQuad> getQuads( IBlockState state, EnumFacing side, @Nonnull Random rand, @Nonnull IModelData data )
     {
         if( side != null )
         {
@@ -61,14 +70,10 @@ public class TurtleMultiModel implements IBakedModel
     private List<BakedQuad> buildQuads( IBlockState state, EnumFacing side, Random rand )
     {
         ArrayList<BakedQuad> quads = new ArrayList<>();
-        ModelTransformer.transformQuadsTo( quads, m_baseModel.getQuads( state, side, rand ), m_generalTransform );
+        ModelTransformer.transformQuadsTo( quads, m_baseModel.getQuads( state, side, rand, EmptyModelData.INSTANCE ), m_generalTransform );
         if( m_overlayModel != null )
         {
-            ModelTransformer.transformQuadsTo( quads, m_overlayModel.getQuads( state, side, rand ), m_generalTransform );
-        }
-        if( m_overlayModel != null )
-        {
-            ModelTransformer.transformQuadsTo( quads, m_overlayModel.getQuads( state, side, rand ), m_generalTransform );
+            ModelTransformer.transformQuadsTo( quads, m_overlayModel.getQuads( state, side, rand, EmptyModelData.INSTANCE ), m_generalTransform );
         }
         if( m_leftUpgradeModel != null )
         {
@@ -78,7 +83,7 @@ public class TurtleMultiModel implements IBakedModel
                 upgradeTransform = new Matrix4f( m_generalTransform );
                 upgradeTransform.mul( m_leftUpgradeTransform );
             }
-            ModelTransformer.transformQuadsTo( quads, m_leftUpgradeModel.getQuads( state, side, rand ), upgradeTransform );
+            ModelTransformer.transformQuadsTo( quads, m_leftUpgradeModel.getQuads( state, side, rand, EmptyModelData.INSTANCE ), upgradeTransform );
         }
         if( m_rightUpgradeModel != null )
         {
@@ -88,7 +93,7 @@ public class TurtleMultiModel implements IBakedModel
                 upgradeTransform = new Matrix4f( m_generalTransform );
                 upgradeTransform.mul( m_rightUpgradeTransform );
             }
-            ModelTransformer.transformQuadsTo( quads, m_rightUpgradeModel.getQuads( state, side, rand ), upgradeTransform );
+            ModelTransformer.transformQuadsTo( quads, m_rightUpgradeModel.getQuads( state, side, rand, EmptyModelData.INSTANCE ), upgradeTransform );
         }
         quads.trimToSize();
         return quads;
@@ -122,7 +127,7 @@ public class TurtleMultiModel implements IBakedModel
     @Nonnull
     @Override
     @Deprecated
-    public ItemCameraTransforms getItemCameraTransforms()
+    public net.minecraft.client.renderer.model.ItemCameraTransforms getItemCameraTransforms()
     {
         return m_baseModel.getItemCameraTransforms();
     }

src/main/java/dan200/computercraft/client/render/TurtleSmartItemModel.java

@@ -21,6 +21,7 @@ import net.minecraft.item.ItemStack;
 import net.minecraft.util.EnumFacing;
 import net.minecraft.util.ResourceLocation;
 import net.minecraft.world.World;
+import net.minecraftforge.client.model.data.IModelData;
 import org.apache.commons.lang3.tuple.Pair;
 
 import javax.annotation.Nonnull;
@@ -167,11 +168,20 @@ public class TurtleSmartItemModel implements IBakedModel
 
     @Nonnull
     @Override
+    @Deprecated
     public List<BakedQuad> getQuads( IBlockState state, EnumFacing facing, @Nonnull Random rand )
     {
         return familyModel.getQuads( state, facing, rand );
     }
 
+    @Nonnull
+    @Override
+    @Deprecated
+    public List<BakedQuad> getQuads( IBlockState state, EnumFacing facing, @Nonnull Random rand, @Nonnull IModelData data )
+    {
+        return familyModel.getQuads( state, facing, rand, data );
+    }
+
     @Override
     public boolean isAmbientOcclusion()
     {

src/main/java/dan200/computercraft/core/apis/ApiFactories.java

@@ -6,13 +6,13 @@
 
 package dan200.computercraft.core.apis;
 
-import com.google.common.base.Preconditions;
 import dan200.computercraft.api.lua.ILuaAPIFactory;
 
 import javax.annotation.Nonnull;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.LinkedHashSet;
+import java.util.Objects;
 
 public final class ApiFactories
 {
@@ -25,7 +25,7 @@ public final class ApiFactories
 
     public static synchronized void register( @Nonnull ILuaAPIFactory factory )
     {
-        Preconditions.checkNotNull( factory, "provider cannot be null" );
+        Objects.requireNonNull( factory, "provider cannot be null" );
         factories.add( factory );
     }
 

src/main/java/dan200/computercraft/core/apis/ComputerAccess.java

@@ -6,7 +6,6 @@
 
 package dan200.computercraft.core.apis;
 
-import com.google.common.base.Preconditions;
 import dan200.computercraft.api.filesystem.IMount;
 import dan200.computercraft.api.filesystem.IWritableMount;
 import dan200.computercraft.api.peripheral.IComputerAccess;
@@ -121,7 +120,7 @@ public abstract class ComputerAccess implements IComputerAccess
     @Override
     public void queueEvent( @Nonnull final String event, final Object[] arguments )
     {
-        Preconditions.checkNotNull( event, "event cannot be null" );
+        Objects.requireNonNull( event, "event cannot be null" );
         m_environment.queueEvent( event, arguments );
     }
 

src/main/java/dan200/computercraft/core/apis/FSAPI.java

@@ -43,9 +43,7 @@ public class FSAPI implements ILuaAPI
     @Override
     public String[] getNames()
     {
-        return new String[] {
-            "fs"
-        };
+        return new String[] { "fs" };
     }
 
     @Override

src/main/java/dan200/computercraft/core/apis/HTTPAPI.java

@@ -42,9 +42,7 @@ public class HTTPAPI implements ILuaAPI
     @Override
     public String[] getNames()
     {
-        return new String[] {
-            "http"
-        };
+        return new String[] { "http" };
     }
 
     @Override
@@ -83,6 +81,7 @@ public class HTTPAPI implements ILuaAPI
     }
 
     @Override
+    @SuppressWarnings( "resource" )
     public Object[] callMethod( @Nonnull ILuaContext context, int method, @Nonnull Object[] args ) throws LuaException
     {
         switch( method )
@@ -95,7 +94,7 @@ public class HTTPAPI implements ILuaAPI
 
                 if( args.length >= 1 && args[0] instanceof Map )
                 {
-                    Map<?, ?> options = (Map) args[0];
+                    Map<?, ?> options = (Map<?, ?>) args[0];
                     address = getStringField( options, "url" );
                     postString = optStringField( options, "body", null );
                     headerTable = optTableField( options, "headers", Collections.emptyMap() );
@@ -135,7 +134,6 @@ public class HTTPAPI implements ILuaAPI
                 try
                 {
                     URI uri = HttpRequest.checkUri( address );
-
                     HttpRequest request = new HttpRequest( requests, m_apiEnvironment, address, postString, headers, binary, redirect );
 
                     long requestBody = request.body().readableBytes() + HttpRequest.getHeaderSize( headers );

src/main/java/dan200/computercraft/core/apis/IAPIEnvironment.java

@@ -8,6 +8,7 @@ package dan200.computercraft.core.apis;
 
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.api.peripheral.IWorkMonitor;
+import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.core.computer.IComputerEnvironment;
 import dan200.computercraft.core.filesystem.FileSystem;
 import dan200.computercraft.core.terminal.Terminal;
@@ -18,16 +19,10 @@ import javax.annotation.Nullable;
 
 public interface IAPIEnvironment
 {
-    String[] SIDE_NAMES = new String[] {
-        "bottom", "top", "back", "front", "right", "left",
-    };
-
-    int SIDE_COUNT = 6;
-
     @FunctionalInterface
     interface IPeripheralChangeListener
     {
-        void onPeripheralChanged( int side, @Nullable IPeripheral newPeripheral );
+        void onPeripheralChanged( ComputerSide side, @Nullable IPeripheral newPeripheral );
     }
 
     int getComputerID();
@@ -49,22 +44,22 @@ public interface IAPIEnvironment
 
     void queueEvent( String event, Object[] args );
 
-    void setOutput( int side, int output );
+    void setOutput( ComputerSide side, int output );
 
-    int getOutput( int side );
+    int getOutput( ComputerSide side );
 
-    int getInput( int side );
+    int getInput( ComputerSide side );
 
-    void setBundledOutput( int side, int output );
+    void setBundledOutput( ComputerSide side, int output );
 
-    int getBundledOutput( int side );
+    int getBundledOutput( ComputerSide side );
 
-    int getBundledInput( int side );
+    int getBundledInput( ComputerSide side );
 
     void setPeripheralChangeListener( @Nullable IPeripheralChangeListener listener );
 
     @Nullable
-    IPeripheral getPeripheral( int side );
+    IPeripheral getPeripheral( ComputerSide side );
 
     String getLabel();
 

src/main/java/dan200/computercraft/core/apis/ILuaAPI.java

@@ -10,6 +10,7 @@ package dan200.computercraft.core.apis;
  * This exists purely to ensure binary compatibility.
  *
  * @see dan200.computercraft.api.lua.ILuaAPI
+ * @deprecated Use the version in the public API. Only exists for compatibility with CCEmuX.
  */
 @Deprecated
 public interface ILuaAPI extends dan200.computercraft.api.lua.ILuaAPI

src/main/java/dan200/computercraft/core/apis/LuaDateTime.java

@@ -0,0 +1,281 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+
+package dan200.computercraft.core.apis;
+
+import dan200.computercraft.api.lua.LuaException;
+
+import java.time.Instant;
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.time.ZoneOffset;
+import java.time.format.DateTimeFormatterBuilder;
+import java.time.format.TextStyle;
+import java.time.temporal.*;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.LongUnaryOperator;
+
+final class LuaDateTime
+{
+    private LuaDateTime()
+    {
+    }
+
+    static void format( DateTimeFormatterBuilder formatter, String format, ZoneOffset offset ) throws LuaException
+    {
+        for( int i = 0; i < format.length(); )
+        {
+            char c;
+            switch( c = format.charAt( i++ ) )
+            {
+                case '\n':
+                    formatter.appendLiteral( '\n' );
+                    break;
+                default:
+                    formatter.appendLiteral( c );
+                    break;
+                case '%':
+                    if( i >= format.length() ) break;
+                    switch( c = format.charAt( i++ ) )
+                    {
+                        default:
+                            throw new LuaException( "bad argument #1: invalid conversion specifier '%" + c + "'" );
+
+                        case '%':
+                            formatter.appendLiteral( '%' );
+                            break;
+                        case 'a':
+                            formatter.appendText( ChronoField.DAY_OF_WEEK, TextStyle.SHORT );
+                            break;
+                        case 'A':
+                            formatter.appendText( ChronoField.DAY_OF_WEEK, TextStyle.FULL );
+                            break;
+                        case 'b':
+                        case 'h':
+                            formatter.appendText( ChronoField.MONTH_OF_YEAR, TextStyle.SHORT );
+                            break;
+                        case 'B':
+                            formatter.appendText( ChronoField.MONTH_OF_YEAR, TextStyle.FULL );
+                            break;
+                        case 'c':
+                            format( formatter, "%a %b %e %H:%M:%S %Y", offset );
+                            break;
+                        case 'C':
+                            formatter.appendValueReduced( CENTURY, 2, 2, 0 );
+                            break;
+                        case 'd':
+                            formatter.appendValue( ChronoField.DAY_OF_MONTH, 2 );
+                            break;
+                        case 'D':
+                        case 'x':
+                            format( formatter, "%m/%d/%y", offset );
+                            break;
+                        case 'e':
+                            formatter.padNext( 2 ).appendValue( ChronoField.DAY_OF_MONTH );
+                            break;
+                        case 'F':
+                            format( formatter, "%Y-%m-%d", offset );
+                            break;
+                        case 'g':
+                            formatter.appendValueReduced( IsoFields.WEEK_BASED_YEAR, 2, 2, 0 );
+                            break;
+                        case 'G':
+                            formatter.appendValue( IsoFields.WEEK_BASED_YEAR );
+                            break;
+                        case 'H':
+                            formatter.appendValue( ChronoField.HOUR_OF_DAY, 2 );
+                            break;
+                        case 'I':
+                            formatter.appendValue( ChronoField.HOUR_OF_AMPM );
+                            break;
+                        case 'j':
+                            formatter.appendValue( ChronoField.DAY_OF_YEAR, 3 );
+                            break;
+                        case 'm':
+                            formatter.appendValue( ChronoField.MONTH_OF_YEAR, 2 );
+                            break;
+                        case 'M':
+                            formatter.appendValue( ChronoField.MINUTE_OF_HOUR, 2 );
+                            break;
+                        case 'n':
+                            formatter.appendLiteral( '\n' );
+                            break;
+                        case 'p':
+                            formatter.appendText( ChronoField.AMPM_OF_DAY );
+                            break;
+                        case 'r':
+                            format( formatter, "%I:%M:%S %p", offset );
+                            break;
+                        case 'R':
+                            format( formatter, "%H:%M", offset );
+                            break;
+                        case 'S':
+                            formatter.appendValue( ChronoField.SECOND_OF_MINUTE, 2 );
+                            break;
+                        case 't':
+                            formatter.appendLiteral( '\t' );
+                            break;
+                        case 'T':
+                        case 'X':
+                            format( formatter, "%H:%M:%S", offset );
+                            break;
+                        case 'u':
+                            formatter.appendValue( ChronoField.DAY_OF_WEEK );
+                            break;
+                        case 'U':
+                            formatter.appendValue( ChronoField.ALIGNED_WEEK_OF_YEAR, 2 );
+                            break;
+                        case 'V':
+                            formatter.appendValue( IsoFields.WEEK_OF_WEEK_BASED_YEAR, 2 );
+                            break;
+                        case 'w':
+                            formatter.appendValue( ZERO_WEEK );
+                            break;
+                        case 'W':
+                            formatter.appendValue( WeekFields.ISO.weekOfYear(), 2 );
+                            break;
+                        case 'y':
+                            formatter.appendValueReduced( ChronoField.YEAR, 2, 2, 0 );
+                            break;
+                        case 'Y':
+                            formatter.appendValue( ChronoField.YEAR );
+                            break;
+                        case 'z':
+                            formatter.appendOffset( "+HHMM", "+0000" );
+                            break;
+                        case 'Z':
+                            formatter.appendChronologyId();
+                            break;
+                    }
+            }
+        }
+    }
+
+    static long fromTable( Map<?, ?> table ) throws LuaException
+    {
+        int year = getField( table, "year", -1 );
+        int month = getField( table, "month", -1 );
+        int day = getField( table, "day", -1 );
+        int hour = getField( table, "hour", 12 );
+        int minute = getField( table, "min", 12 );
+        int second = getField( table, "sec", 12 );
+        LocalDateTime time = LocalDateTime.of( year, month, day, hour, minute, second );
+
+        Boolean isDst = getBoolField( table, "isdst" );
+        if( isDst != null )
+        {
+            boolean requireDst = isDst;
+            for( ZoneOffset possibleOffset : ZoneOffset.systemDefault().getRules().getValidOffsets( time ) )
+            {
+                Instant instant = time.toInstant( possibleOffset );
+                if( possibleOffset.getRules().getDaylightSavings( instant ).isZero() == requireDst )
+                {
+                    return instant.getEpochSecond();
+                }
+            }
+        }
+
+        ZoneOffset offset = ZoneOffset.systemDefault().getRules().getOffset( time );
+        return time.toInstant( offset ).getEpochSecond();
+    }
+
+    static Map<String, ?> toTable( TemporalAccessor date, ZoneId offset, Instant instant )
+    {
+        HashMap<String, Object> table = new HashMap<>( 9 );
+        table.put( "year", date.getLong( ChronoField.YEAR ) );
+        table.put( "month", date.getLong( ChronoField.MONTH_OF_YEAR ) );
+        table.put( "day", date.getLong( ChronoField.DAY_OF_MONTH ) );
+        table.put( "hour", date.getLong( ChronoField.HOUR_OF_DAY ) );
+        table.put( "min", date.getLong( ChronoField.MINUTE_OF_HOUR ) );
+        table.put( "sec", date.getLong( ChronoField.SECOND_OF_MINUTE ) );
+        table.put( "wday", date.getLong( WeekFields.SUNDAY_START.dayOfWeek() ) );
+        table.put( "yday", date.getLong( ChronoField.DAY_OF_YEAR ) );
+        table.put( "isdst", offset.getRules().isDaylightSavings( instant ) );
+        return table;
+    }
+
+    private static int getField( Map<?, ?> table, String field, int def ) throws LuaException
+    {
+        Object value = table.get( field );
+        if( value instanceof Number ) return ((Number) value).intValue();
+        if( def < 0 ) throw new LuaException( "field \"" + field + "\" missing in date table" );
+        return def;
+    }
+
+    private static Boolean getBoolField( Map<?, ?> table, String field ) throws LuaException
+    {
+        Object value = table.get( field );
+        if( value instanceof Boolean || value == null ) return (Boolean) value;
+        throw new LuaException( "field \"" + field + "\" missing in date table" );
+    }
+
+    private static final TemporalField CENTURY = map( ChronoField.YEAR, ValueRange.of( 0, 6 ), x -> (x / 100) % 100 );
+    private static final TemporalField ZERO_WEEK = map( WeekFields.SUNDAY_START.dayOfWeek(), ValueRange.of( 0, 6 ), x -> x - 1 );
+
+    private static TemporalField map( TemporalField field, ValueRange range, LongUnaryOperator convert )
+    {
+        return new TemporalField()
+        {
+            private final ValueRange range = ValueRange.of( 0, 99 );
+
+            @Override
+            public TemporalUnit getBaseUnit()
+            {
+                return field.getBaseUnit();
+            }
+
+            @Override
+            public TemporalUnit getRangeUnit()
+            {
+                return field.getRangeUnit();
+            }
+
+            @Override
+            public ValueRange range()
+            {
+                return range;
+            }
+
+            @Override
+            public boolean isDateBased()
+            {
+                return field.isDateBased();
+            }
+
+            @Override
+            public boolean isTimeBased()
+            {
+                return field.isTimeBased();
+            }
+
+            @Override
+            public boolean isSupportedBy( TemporalAccessor temporal )
+            {
+                return field.isSupportedBy( temporal );
+            }
+
+            @Override
+            public ValueRange rangeRefinedBy( TemporalAccessor temporal )
+            {
+                return range;
+            }
+
+            @Override
+            public long getFrom( TemporalAccessor temporal )
+            {
+                return convert.applyAsLong( temporal.getLong( field ) );
+            }
+
+            @Override
+            @SuppressWarnings( "unchecked" )
+            public <R extends Temporal> R adjustInto( R temporal, long newValue )
+            {
+                return (R) temporal.with( field, newValue );
+            }
+        };
+    }
+}

src/main/java/dan200/computercraft/core/apis/OSAPI.java

@@ -12,6 +12,11 @@ import dan200.computercraft.api.lua.LuaException;
 import dan200.computercraft.shared.util.StringUtil;
 
 import javax.annotation.Nonnull;
+import java.time.Instant;
+import java.time.ZoneId;
+import java.time.ZoneOffset;
+import java.time.ZonedDateTime;
+import java.time.format.DateTimeFormatterBuilder;
 import java.util.*;
 
 import static dan200.computercraft.core.apis.ArgumentHelper.*;
@@ -31,9 +36,9 @@ public class OSAPI implements ILuaAPI
 
     private static class Timer
     {
-        public int m_ticksLeft;
+        int m_ticksLeft;
 
-        public Timer( int ticksLeft )
+        Timer( int ticksLeft )
         {
             m_ticksLeft = ticksLeft;
         }
@@ -41,10 +46,10 @@ public class OSAPI implements ILuaAPI
 
     private static class Alarm implements Comparable<Alarm>
     {
-        public final double m_time;
-        public final int m_day;
+        final double m_time;
+        final int m_day;
 
-        public Alarm( double time, int day )
+        Alarm( double time, int day )
         {
             m_time = time;
             m_day = day;
@@ -73,9 +78,7 @@ public class OSAPI implements ILuaAPI
     @Override
     public String[] getNames()
     {
-        return new String[] {
-            "os"
-        };
+        return new String[] { "os" };
     }
 
     @Override
@@ -184,11 +187,12 @@ public class OSAPI implements ILuaAPI
             "day",
             "cancelTimer",
             "cancelAlarm",
-            "epoch"
+            "epoch",
+            "date",
         };
     }
 
-    private float getTimeForCalendar( Calendar c )
+    private static float getTimeForCalendar( Calendar c )
     {
         float time = c.get( Calendar.HOUR_OF_DAY );
         time += c.get( Calendar.MINUTE ) / 60.0f;
@@ -196,7 +200,7 @@ public class OSAPI implements ILuaAPI
         return time;
     }
 
-    private int getDayForCalendar( Calendar c )
+    private static int getDayForCalendar( Calendar c )
     {
         GregorianCalendar g = c instanceof GregorianCalendar ? (GregorianCalendar) c : new GregorianCalendar();
         int year = c.get( Calendar.YEAR );
@@ -209,7 +213,7 @@ public class OSAPI implements ILuaAPI
         return day;
     }
 
-    private long getEpochForCalendar( Calendar c )
+    private static long getEpochForCalendar( Calendar c )
     {
         return c.getTime().getTime();
     }
@@ -282,6 +286,9 @@ public class OSAPI implements ILuaAPI
             case 11:
             {
                 // time
+                Object value = args.length > 0 ? args[0] : null;
+                if( value instanceof Map ) return new Object[] { LuaDateTime.fromTable( (Map<?, ?>) value ) };
+
                 String param = optString( args, 0, "ingame" );
                 switch( param.toLowerCase( Locale.ROOT ) )
                 {
@@ -355,9 +362,8 @@ public class OSAPI implements ILuaAPI
                 }
                 return null;
             }
-            case 15:
+            case 15: // epoch
             {
-                // epoch
                 String param = optString( args, 0, "ingame" );
                 switch( param.toLowerCase( Locale.ROOT ) )
                 {
@@ -377,14 +383,39 @@ public class OSAPI implements ILuaAPI
                         // Get in-game epoch
                         synchronized( m_alarms )
                         {
-                            return new Object[] {
-                                m_day * 86400000 + (int) (m_time * 3600000.0f)
-                            };
+                            return new Object[] { m_day * 86400000 + (int) (m_time * 3600000.0f) };
                         }
                     default:
                         throw new LuaException( "Unsupported operation" );
                 }
             }
+            case 16: // date
+            {
+                String format = optString( args, 0, "%c" );
+                long time = optLong( args, 1, Instant.now().getEpochSecond() );
+
+                Instant instant = Instant.ofEpochSecond( time );
+                ZonedDateTime date;
+                ZoneOffset offset;
+                if( format.startsWith( "!" ) )
+                {
+                    offset = ZoneOffset.UTC;
+                    date = ZonedDateTime.ofInstant( instant, offset );
+                    format = format.substring( 1 );
+                }
+                else
+                {
+                    ZoneId id = ZoneId.systemDefault();
+                    offset = id.getRules().getOffset( instant );
+                    date = ZonedDateTime.ofInstant( instant, id );
+                }
+
+                if( format.equals( "*t" ) ) return new Object[] { LuaDateTime.toTable( date, offset, instant ) };
+
+                DateTimeFormatterBuilder formatter = new DateTimeFormatterBuilder();
+                LuaDateTime.format( formatter, format, offset );
+                return new Object[] { formatter.toFormatter( Locale.ROOT ).format( date ) };
+            }
             default:
                 return null;
         }

src/main/java/dan200/computercraft/core/apis/PeripheralAPI.java

@@ -12,6 +12,7 @@ import dan200.computercraft.api.lua.ILuaAPI;
 import dan200.computercraft.api.lua.ILuaContext;
 import dan200.computercraft.api.lua.LuaException;
 import dan200.computercraft.api.peripheral.IPeripheral;
+import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.core.tracking.TrackingField;
 
 import javax.annotation.Nonnull;
@@ -35,7 +36,7 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
         private Map<String, Integer> m_methodMap;
         private boolean m_attached;
 
-        public PeripheralWrapper( IPeripheral peripheral, String side )
+        PeripheralWrapper( IPeripheral peripheral, String side )
         {
             super( m_environment );
             m_side = side;
@@ -245,32 +246,33 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
     // IPeripheralChangeListener
 
     @Override
-    public void onPeripheralChanged( int side, IPeripheral newPeripheral )
+    public void onPeripheralChanged( ComputerSide side, IPeripheral newPeripheral )
     {
         synchronized( m_peripherals )
         {
-            if( m_peripherals[side] != null )
+            int index = side.ordinal();
+            if( m_peripherals[index] != null )
             {
                 // Queue a detachment
-                final PeripheralWrapper wrapper = m_peripherals[side];
+                final PeripheralWrapper wrapper = m_peripherals[index];
                 if( wrapper.isAttached() ) wrapper.detach();
 
                 // Queue a detachment event
-                m_environment.queueEvent( "peripheral_detach", new Object[] { IAPIEnvironment.SIDE_NAMES[side] } );
+                m_environment.queueEvent( "peripheral_detach", new Object[] { side.getName() } );
             }
 
             // Assign the new peripheral
-            m_peripherals[side] = newPeripheral == null ? null
-                : new PeripheralWrapper( newPeripheral, IAPIEnvironment.SIDE_NAMES[side] );
+            m_peripherals[index] = newPeripheral == null ? null
+                : new PeripheralWrapper( newPeripheral, side.getName() );
 
-            if( m_peripherals[side] != null )
+            if( m_peripherals[index] != null )
             {
                 // Queue an attachment
-                final PeripheralWrapper wrapper = m_peripherals[side];
+                final PeripheralWrapper wrapper = m_peripherals[index];
                 if( m_running && !wrapper.isAttached() ) wrapper.attach();
 
                 // Queue an attachment event
-                m_environment.queueEvent( "peripheral", new Object[] { IAPIEnvironment.SIDE_NAMES[side] } );
+                m_environment.queueEvent( "peripheral", new Object[] { side.getName() } );
             }
         }
     }
@@ -280,9 +282,7 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
     @Override
     public String[] getNames()
     {
-        return new String[] {
-            "peripheral"
-        };
+        return new String[] { "peripheral" };
     }
 
     @Override
@@ -324,7 +324,7 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
             "isPresent",
             "getType",
             "getMethods",
-            "call"
+            "call",
         };
     }
 
@@ -337,16 +337,13 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
             {
                 // isPresent
                 boolean present = false;
-                int side = parseSide( args );
-                if( side >= 0 )
+                ComputerSide side = ComputerSide.valueOfInsensitive( getString( args, 0 ) );
+                if( side != null )
                 {
                     synchronized( m_peripherals )
                     {
-                        PeripheralWrapper p = m_peripherals[side];
-                        if( p != null )
-                        {
-                            present = true;
-                        }
+                        PeripheralWrapper p = m_peripherals[side.ordinal()];
+                        if( p != null ) present = true;
                     }
                 }
                 return new Object[] { present };
@@ -354,21 +351,13 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
             case 1:
             {
                 // getType
-                String type = null;
-                int side = parseSide( args );
-                if( side >= 0 )
+                ComputerSide side = ComputerSide.valueOfInsensitive( getString( args, 0 ) );
+                if( side != null )
                 {
                     synchronized( m_peripherals )
                     {
-                        PeripheralWrapper p = m_peripherals[side];
-                        if( p != null )
-                        {
-                            type = p.getType();
-                        }
-                    }
-                    if( type != null )
-                    {
-                        return new Object[] { type };
+                        PeripheralWrapper p = m_peripherals[side.ordinal()];
+                        if( p != null ) return new Object[] { p.getType() };
                     }
                 }
                 return null;
@@ -377,12 +366,12 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
             {
                 // getMethods
                 String[] methods = null;
-                int side = parseSide( args );
-                if( side >= 0 )
+                ComputerSide side = ComputerSide.valueOfInsensitive( getString( args, 0 ) );
+                if( side != null )
                 {
                     synchronized( m_peripherals )
                     {
-                        PeripheralWrapper p = m_peripherals[side];
+                        PeripheralWrapper p = m_peripherals[side.ordinal()];
                         if( p != null )
                         {
                             methods = p.getMethods();
@@ -403,16 +392,16 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
             case 3:
             {
                 // call
-                int side = parseSide( args );
+                ComputerSide side = ComputerSide.valueOfInsensitive( getString( args, 0 ) );
                 String methodName = getString( args, 1 );
                 Object[] methodArgs = Arrays.copyOfRange( args, 2, args.length );
 
-                if( side >= 0 )
+                if( side != null )
                 {
                     PeripheralWrapper p;
                     synchronized( m_peripherals )
                     {
-                        p = m_peripherals[side];
+                        p = m_peripherals[side.ordinal()];
                     }
                     if( p != null )
                     {
@@ -425,19 +414,4 @@ public class PeripheralAPI implements ILuaAPI, IAPIEnvironment.IPeripheralChange
                 return null;
         }
     }
-
-    // Privates
-
-    private int parseSide( Object[] args ) throws LuaException
-    {
-        String side = getString( args, 0 );
-        for( int n = 0; n < IAPIEnvironment.SIDE_NAMES.length; n++ )
-        {
-            if( side.equals( IAPIEnvironment.SIDE_NAMES[n] ) )
-            {
-                return n;
-            }
-        }
-        return -1;
-    }
 }

src/main/java/dan200/computercraft/core/apis/RedstoneAPI.java

@@ -9,6 +9,7 @@ package dan200.computercraft.core.apis;
 import dan200.computercraft.api.lua.ILuaAPI;
 import dan200.computercraft.api.lua.ILuaContext;
 import dan200.computercraft.api.lua.LuaException;
+import dan200.computercraft.core.computer.ComputerSide;
 
 import javax.annotation.Nonnull;
 import java.util.HashMap;
@@ -28,9 +29,7 @@ public class RedstoneAPI implements ILuaAPI
     @Override
     public String[] getNames()
     {
-        return new String[] {
-            "rs", "redstone"
-        };
+        return new String[] { "rs", "redstone" };
     }
 
     @Nonnull
@@ -64,56 +63,40 @@ public class RedstoneAPI implements ILuaAPI
             {
                 // getSides
                 Map<Object, Object> table = new HashMap<>();
-                for( int i = 0; i < IAPIEnvironment.SIDE_NAMES.length; i++ )
+                for( int i = 0; i < ComputerSide.NAMES.length; i++ )
                 {
-                    table.put( i + 1, IAPIEnvironment.SIDE_NAMES[i] );
+                    table.put( i + 1, ComputerSide.NAMES[i] );
                 }
                 return new Object[] { table };
             }
             case 1:
             {
                 // setOutput
-                int side = parseSide( args );
+                ComputerSide side = parseSide( args );
                 boolean output = getBoolean( args, 1 );
                 m_environment.setOutput( side, output ? 15 : 0 );
                 return null;
             }
-            case 2:
-            {
-                // getOutput
-                int side = parseSide( args );
-                return new Object[] { m_environment.getOutput( side ) > 0 };
-            }
-            case 3:
-            {
-                // getInput
-                int side = parseSide( args );
-                return new Object[] { m_environment.getInput( side ) > 0 };
-            }
+            case 2: // getOutput
+                return new Object[] { m_environment.getOutput( parseSide( args ) ) > 0 };
+            case 3: // getInput
+                return new Object[] { m_environment.getInput( parseSide( args ) ) > 0 };
             case 4:
             {
                 // setBundledOutput
-                int side = parseSide( args );
+                ComputerSide side = parseSide( args );
                 int output = getInt( args, 1 );
                 m_environment.setBundledOutput( side, output );
                 return null;
             }
-            case 5:
-            {
-                // getBundledOutput
-                int side = parseSide( args );
-                return new Object[] { m_environment.getBundledOutput( side ) };
-            }
-            case 6:
-            {
-                // getBundledInput
-                int side = parseSide( args );
-                return new Object[] { m_environment.getBundledInput( side ) };
-            }
+            case 5: // getBundledOutput
+                return new Object[] { m_environment.getBundledOutput( parseSide( args ) ) };
+            case 6: // getBundledInput
+                return new Object[] { m_environment.getBundledInput( parseSide( args ) ) };
             case 7:
             {
                 // testBundledInput
-                int side = parseSide( args );
+                ComputerSide side = parseSide( args );
                 int mask = getInt( args, 1 );
                 int input = m_environment.getBundledInput( side );
                 return new Object[] { (input & mask) == mask };
@@ -122,7 +105,7 @@ public class RedstoneAPI implements ILuaAPI
             case 9:
             {
                 // setAnalogOutput/setAnalogueOutput
-                int side = parseSide( args );
+                ComputerSide side = parseSide( args );
                 int output = getInt( args, 1 );
                 if( output < 0 || output > 15 )
                 {
@@ -132,34 +115,20 @@ public class RedstoneAPI implements ILuaAPI
                 return null;
             }
             case 10:
-            case 11:
-            {
-                // getAnalogOutput/getAnalogueOutput
-                int side = parseSide( args );
-                return new Object[] { m_environment.getOutput( side ) };
-            }
+            case 11: // getAnalogOutput/getAnalogueOutput
+                return new Object[] { m_environment.getOutput( parseSide( args ) ) };
             case 12:
-            case 13:
-            {
-                // getAnalogInput/getAnalogueInput
-                int side = parseSide( args );
-                return new Object[] { m_environment.getInput( side ) };
-            }
+            case 13: // getAnalogInput/getAnalogueInput
+                return new Object[] { m_environment.getInput( parseSide( args ) ) };
             default:
                 return null;
         }
     }
 
-    private static int parseSide( Object[] args ) throws LuaException
+    private static ComputerSide parseSide( Object[] args ) throws LuaException
     {
-        String side = getString( args, 0 );
-        for( int n = 0; n < IAPIEnvironment.SIDE_NAMES.length; n++ )
-        {
-            if( side.equals( IAPIEnvironment.SIDE_NAMES[n] ) )
-            {
-                return n;
-            }
-        }
-        throw new LuaException( "Invalid side." );
+        ComputerSide side = ComputerSide.valueOfInsensitive( getString( args, 0 ) );
+        if( side == null ) throw new LuaException( "Invalid side." );
+        return side;
     }
 }

src/main/java/dan200/computercraft/core/apis/TermAPI.java

@@ -33,9 +33,7 @@ public class TermAPI implements ILuaAPI
     @Override
     public String[] getNames()
     {
-        return new String[] {
-            "term"
-        };
+        return new String[] { "term" };
     }
 
     @Nonnull
@@ -89,9 +87,7 @@ public class TermAPI implements ILuaAPI
 
     public static Object[] encodeColour( int colour ) throws LuaException
     {
-        return new Object[] {
-            1 << colour
-        };
+        return new Object[] { 1 << colour };
     }
 
     public static void setColour( Terminal terminal, int colour, double r, double g, double b )

src/main/java/dan200/computercraft/core/apis/handles/BinaryReadableHandle.java

@@ -212,6 +212,7 @@ public class BinaryReadableHandle extends HandleGeneric
                 }
             }
             case 3: // close
+                checkOpen();
                 close();
                 return null;
             case 4: // seek

src/main/java/dan200/computercraft/core/apis/handles/BinaryWritableHandle.java

@@ -95,6 +95,7 @@ public class BinaryWritableHandle extends HandleGeneric
                     return null;
                 }
             case 2: // close
+                checkOpen();
                 close();
                 return null;
             case 3: // seek

src/main/java/dan200/computercraft/core/apis/handles/EncodedReadableHandle.java

@@ -152,6 +152,7 @@ public class EncodedReadableHandle extends HandleGeneric
                     return null;
                 }
             case 3: // close
+                checkOpen();
                 close();
                 return null;
             default:

src/main/java/dan200/computercraft/core/apis/handles/EncodedWritableHandle.java

@@ -93,6 +93,7 @@ public class EncodedWritableHandle extends HandleGeneric
                     return null;
                 }
             case 3: // close
+                checkOpen();
                 close();
                 return null;
             default:

src/main/java/dan200/computercraft/core/apis/handles/HandleGeneric.java

@@ -37,8 +37,13 @@ public abstract class HandleGeneric implements ILuaObject
     protected final void close()
     {
         m_open = false;
-        IoUtil.closeQuietly( m_closable );
-        m_closable = null;
+
+        Closeable closeable = m_closable;
+        if( closeable != null )
+        {
+            IoUtil.closeQuietly( closeable );
+            m_closable = null;
+        }
     }
 
     /**

src/main/java/dan200/computercraft/core/apis/http/Resource.java

@@ -72,7 +72,8 @@ public abstract class Resource<T extends Resource<T>> implements Closeable
      */
     protected void dispose()
     {
-        @SuppressWarnings( "unchecked" ) T thisT = (T) this;
+        @SuppressWarnings( "unchecked" )
+        T thisT = (T) this;
         limiter.release( thisT );
     }
 
@@ -95,7 +96,8 @@ public abstract class Resource<T extends Resource<T>> implements Closeable
 
     public boolean queue( Consumer<T> task )
     {
-        @SuppressWarnings( "unchecked" ) T thisT = (T) this;
+        @SuppressWarnings( "unchecked" )
+        T thisT = (T) this;
         return limiter.queue( thisT, () -> task.accept( thisT ) );
     }
 

src/main/java/dan200/computercraft/core/apis/http/websocket/WebsocketHandle.java

@@ -24,6 +24,7 @@ import java.io.Closeable;
 import java.util.Arrays;
 
 import static dan200.computercraft.core.apis.ArgumentHelper.optBoolean;
+import static dan200.computercraft.core.apis.http.websocket.Websocket.CLOSE_EVENT;
 import static dan200.computercraft.core.apis.http.websocket.Websocket.MESSAGE_EVENT;
 
 public class WebsocketHandle implements ILuaObject, Closeable
@@ -53,15 +54,18 @@ public class WebsocketHandle implements ILuaObject, Closeable
         switch( method )
         {
             case 0: // receive
+                checkOpen();
                 while( true )
                 {
-                    checkOpen();
-
-                    Object[] event = context.pullEvent( MESSAGE_EVENT );
-                    if( event.length >= 3 && Objects.equal( event[1], websocket.address() ) )
+                    Object[] event = context.pullEvent( null );
+                    if( event.length >= 3 && Objects.equal( event[0], MESSAGE_EVENT ) && Objects.equal( event[1], websocket.address() ) )
                     {
                         return Arrays.copyOfRange( event, 2, event.length );
                     }
+                    else if( event.length >= 2 && Objects.equal( event[0], CLOSE_EVENT ) && Objects.equal( event[1], websocket.address() ) && closed )
+                    {
+                        return null;
+                    }
                 }
 
             case 1: // send

src/main/java/dan200/computercraft/core/computer/ComputerExecutor.java

@@ -338,7 +338,7 @@ final class ComputerExecutor
         }
     }
 
-    private FileSystem createFileSystem()
+    IWritableMount getRootMount()
     {
         if( rootMount == null )
         {
@@ -347,11 +347,15 @@ final class ComputerExecutor
                 computer.getComputerEnvironment().getComputerSpaceLimit()
             );
         }
+        return rootMount;
+    }
 
+    private FileSystem createFileSystem()
+    {
         FileSystem filesystem = null;
         try
         {
-            filesystem = new FileSystem( "hdd", rootMount );
+            filesystem = new FileSystem( "hdd", getRootMount() );
 
             IMount romMount = getRomMount();
             if( romMount == null )

src/main/java/dan200/computercraft/core/computer/ComputerSide.java

@@ -0,0 +1,59 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+
+package dan200.computercraft.core.computer;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * A side on a computer. Unlike {@link net.minecraft.util.EnumFacing}, this is relative to the direction the computer is
+ * facing..
+ */
+public enum ComputerSide
+{
+    BOTTOM( "bottom" ),
+    TOP( "top" ),
+    BACK( "back" ),
+    FRONT( "front" ),
+    RIGHT( "right" ),
+    LEFT( "left" );
+
+    public static final String[] NAMES = new String[] { "bottom", "top", "back", "front", "right", "left" };
+
+    public static final int COUNT = 6;
+
+    private static final ComputerSide[] VALUES = values();
+
+    private final String name;
+
+    ComputerSide( String name )
+    {
+        this.name = name;
+    }
+
+    @Nonnull
+    public static ComputerSide valueOf( int side )
+    {
+        return VALUES[side];
+    }
+
+    @Nullable
+    public static ComputerSide valueOfInsensitive( @Nonnull String name )
+    {
+        for( ComputerSide side : VALUES )
+        {
+            if( side.name.equalsIgnoreCase( name ) ) return side;
+        }
+
+        return null;
+    }
+
+    public String getName()
+    {
+        return name;
+    }
+}

src/main/java/dan200/computercraft/core/computer/ComputerSystem.java

@@ -26,12 +26,12 @@ import javax.annotation.Nullable;
  */
 public class ComputerSystem extends ComputerAccess implements IComputerSystem
 {
-    private final IAPIEnvironment m_environment;
+    private final IAPIEnvironment environment;
 
     ComputerSystem( IAPIEnvironment environment )
     {
         super( environment );
-        this.m_environment = environment;
+        this.environment = environment;
     }
 
     @Nonnull
@@ -45,7 +45,7 @@ public class ComputerSystem extends ComputerAccess implements IComputerSystem
     @Override
     public IFileSystem getFileSystem()
     {
-        FileSystem fs = m_environment.getFileSystem();
+        FileSystem fs = environment.getFileSystem();
         return fs == null ? null : fs.getMountWrapper();
     }
 
@@ -53,6 +53,6 @@ public class ComputerSystem extends ComputerAccess implements IComputerSystem
     @Override
     public String getLabel()
     {
-        return m_environment.getLabel();
+        return environment.getLabel();
     }
 }

src/main/java/dan200/computercraft/core/computer/ComputerThread.java

@@ -133,7 +133,6 @@ public final class ComputerThread
         synchronized( threadLock )
         {
             running = true;
-            if( monitor == null || !monitor.isAlive() ) (monitor = monitorFactory.newThread( new Monitor() )).start();
 
             if( runners == null )
             {
@@ -158,6 +157,8 @@ public final class ComputerThread
                     runnerFactory.newThread( runners[i] = new TaskRunner() ).start();
                 }
             }
+
+            if( monitor == null || !monitor.isAlive() ) (monitor = monitorFactory.newThread( new Monitor() )).start();
         }
     }
 
@@ -368,7 +369,16 @@ public final class ComputerThread
                         {
                             TaskRunner runner = currentRunners[i];
                             // If we've no runner, skip.
-                            if( runner == null ) continue;
+                            if( runner == null || runner.owner == null || !runner.owner.isAlive() )
+                            {
+                                if( !running ) continue;
+
+                                // Mark the old runner as dead and start a new one.
+                                ComputerCraft.log.warn( "Previous runner ({}) has crashed, restarting!",
+                                    runner != null && runner.owner != null ? runner.owner.getName() : runner );
+                                if( runner != null ) runner.running = false;
+                                runnerFactory.newThread( runners[i] = new TaskRunner() ).start();
+                            }
 
                             // If the runner has no work, skip
                             ComputerExecutor executor = runner.currentExecutor.get();
@@ -492,7 +502,7 @@ public final class ComputerThread
                 {
                     executor.work();
                 }
-                catch( Exception e )
+                catch( Exception | LinkageError | VirtualMachineError e )
                 {
                     ComputerCraft.log.error( "Error running task on computer #" + executor.getComputer().getID(), e );
                 }

src/main/java/dan200/computercraft/core/computer/Environment.java

@@ -41,17 +41,17 @@ public final class Environment implements IAPIEnvironment
     private final Computer computer;
 
     private boolean internalOutputChanged = false;
-    private final int[] internalOutput = new int[SIDE_COUNT];
-    private final int[] internalBundledOutput = new int[SIDE_COUNT];
+    private final int[] internalOutput = new int[ComputerSide.COUNT];
+    private final int[] internalBundledOutput = new int[ComputerSide.COUNT];
 
-    private final int[] externalOutput = new int[SIDE_COUNT];
-    private final int[] externalBundledOutput = new int[SIDE_COUNT];
+    private final int[] externalOutput = new int[ComputerSide.COUNT];
+    private final int[] externalBundledOutput = new int[ComputerSide.COUNT];
 
     private boolean inputChanged = false;
-    private final int[] input = new int[SIDE_COUNT];
-    private final int[] bundledInput = new int[SIDE_COUNT];
+    private final int[] input = new int[ComputerSide.COUNT];
+    private final int[] bundledInput = new int[ComputerSide.COUNT];
 
-    private final IPeripheral[] peripherals = new IPeripheral[SIDE_COUNT];
+    private final IPeripheral[] peripherals = new IPeripheral[ComputerSide.COUNT];
     private IPeripheralChangeListener peripheralListener = null;
 
     Environment( Computer computer )
@@ -111,85 +111,89 @@ public final class Environment implements IAPIEnvironment
     }
 
     @Override
-    public int getInput( int side )
+    public int getInput( ComputerSide side )
     {
-        return input[side];
+        return input[side.ordinal()];
     }
 
     @Override
-    public int getBundledInput( int side )
+    public int getBundledInput( ComputerSide side )
     {
-        return bundledInput[side];
+        return bundledInput[side.ordinal()];
     }
 
     @Override
-    public void setOutput( int side, int output )
+    public void setOutput( ComputerSide side, int output )
     {
+        int index = side.ordinal();
         synchronized( internalOutput )
         {
-            if( internalOutput[side] != output )
+            if( internalOutput[index] != output )
             {
-                internalOutput[side] = output;
+                internalOutput[index] = output;
                 internalOutputChanged = true;
             }
         }
     }
 
     @Override
-    public int getOutput( int side )
+    public int getOutput( ComputerSide side )
     {
         synchronized( internalOutput )
         {
-            return computer.isOn() ? internalOutput[side] : 0;
+            return computer.isOn() ? internalOutput[side.ordinal()] : 0;
         }
     }
 
     @Override
-    public void setBundledOutput( int side, int output )
+    public void setBundledOutput( ComputerSide side, int output )
     {
+        int index = side.ordinal();
         synchronized( internalOutput )
         {
-            if( internalBundledOutput[side] != output )
+            if( internalBundledOutput[index] != output )
             {
-                internalBundledOutput[side] = output;
+                internalBundledOutput[index] = output;
                 internalOutputChanged = true;
             }
         }
     }
 
     @Override
-    public int getBundledOutput( int side )
+    public int getBundledOutput( ComputerSide side )
     {
         synchronized( internalOutput )
         {
-            return computer.isOn() ? internalBundledOutput[side] : 0;
+            return computer.isOn() ? internalBundledOutput[side.ordinal()] : 0;
         }
     }
 
-    public int getExternalRedstoneOutput( int side )
+    public int getExternalRedstoneOutput( ComputerSide side )
     {
-        return computer.isOn() ? externalOutput[side] : 0;
+        return computer.isOn() ? externalOutput[side.ordinal()] : 0;
     }
 
-    public int getExternalBundledRedstoneOutput( int side )
+    public int getExternalBundledRedstoneOutput( ComputerSide side )
     {
-        return computer.isOn() ? externalBundledOutput[side] : 0;
+        return computer.isOn() ? externalBundledOutput[side.ordinal()] : 0;
     }
 
-    public void setRedstoneInput( int side, int level )
+    public void setRedstoneInput( ComputerSide side, int level )
     {
-        if( input[side] != level )
+        int index = side.ordinal();
+        if( input[index] != level )
         {
-            input[side] = level;
+            input[index] = level;
             inputChanged = true;
         }
     }
 
-    public void setBundledRedstoneInput( int side, int combination )
+    public void setBundledRedstoneInput( ComputerSide side, int combination )
     {
-        if( bundledInput[side] != combination )
+        int index = side.ordinal();
+        if( bundledInput[index] != combination )
         {
-            bundledInput[side] = combination;
+            bundledInput[index] = combination;
             inputChanged = true;
         }
     }
@@ -222,7 +226,7 @@ public final class Environment implements IAPIEnvironment
 
             boolean changed = false;
 
-            for( int i = 0; i < SIDE_COUNT; i++ )
+            for( int i = 0; i < ComputerSide.COUNT; i++ )
             {
                 if( externalOutput[i] != internalOutput[i] )
                 {
@@ -255,24 +259,25 @@ public final class Environment implements IAPIEnvironment
     }
 
     @Override
-    public IPeripheral getPeripheral( int side )
+    public IPeripheral getPeripheral( ComputerSide side )
     {
         synchronized( peripherals )
         {
-            return peripherals[side];
+            return peripherals[side.ordinal()];
         }
     }
 
-    public void setPeripheral( int side, IPeripheral peripheral )
+    public void setPeripheral( ComputerSide side, IPeripheral peripheral )
     {
         synchronized( peripherals )
         {
-            IPeripheral existing = peripherals[side];
+            int index = side.ordinal();
+            IPeripheral existing = peripherals[index];
             if( (existing == null && peripheral != null) ||
                 (existing != null && peripheral == null) ||
                 (existing != null && !existing.equals( peripheral )) )
             {
-                peripherals[side] = peripheral;
+                peripherals[index] = peripheral;
                 if( peripheralListener != null ) peripheralListener.onPeripheralChanged( side, peripheral );
             }
         }

src/main/java/dan200/computercraft/core/computer/MainThread.java

@@ -134,7 +134,7 @@ public final class MainThread
         // Of course, we'll go over the MAX_TICK_TIME most of the time, but eventually that overrun will accumulate
         // and we'll skip a whole tick - bringing the average back down again.
         currentTick++;
-        budget += Math.min( budget + ComputerCraft.maxMainGlobalTime, ComputerCraft.maxMainGlobalTime );
+        budget = Math.min( budget + ComputerCraft.maxMainGlobalTime, ComputerCraft.maxMainGlobalTime );
         canExecute = budget > 0;
 
         // Cool down any warm computers.

src/main/java/dan200/computercraft/core/computer/MainThreadExecutor.java

@@ -224,7 +224,7 @@ final class MainThreadExecutor implements IWorkMonitor
     {
         state = State.COOLING;
         currentTick = MainThread.currentTick();
-        budget += Math.min( budget + ComputerCraft.maxMainComputerTime, ComputerCraft.maxMainComputerTime );
+        budget = Math.min( budget + ComputerCraft.maxMainComputerTime, ComputerCraft.maxMainComputerTime );
         if( budget < ComputerCraft.maxMainComputerTime ) return false;
 
         state = State.COOL;

src/main/java/dan200/computercraft/core/filesystem/ComboMount.java

@@ -6,6 +6,7 @@
 
 package dan200.computercraft.core.filesystem;
 
+import dan200.computercraft.api.filesystem.FileOperationException;
 import dan200.computercraft.api.filesystem.IMount;
 
 import javax.annotation.Nonnull;
@@ -95,7 +96,7 @@ public class ComboMount implements IMount
         }
         else
         {
-            throw new IOException( "/" + path + ": Not a directory" );
+            throw new FileOperationException( path, "Not a directory" );
         }
     }
 
@@ -110,7 +111,7 @@ public class ComboMount implements IMount
                 return part.getSize( path );
             }
         }
-        throw new IOException( "/" + path + ": No such file" );
+        throw new FileOperationException( path, "No such file" );
     }
 
     @Nonnull
@@ -126,7 +127,7 @@ public class ComboMount implements IMount
                 return part.openForRead( path );
             }
         }
-        throw new IOException( "/" + path + ": No such file" );
+        throw new FileOperationException( path, "No such file" );
     }
 
     @Nonnull
@@ -141,6 +142,6 @@ public class ComboMount implements IMount
                 return part.openChannelForRead( path );
             }
         }
-        throw new IOException( "/" + path + ": No such file" );
+        throw new FileOperationException( path, "No such file" );
     }
 }

src/main/java/dan200/computercraft/core/filesystem/EmptyMount.java

@@ -6,6 +6,7 @@
 
 package dan200.computercraft.core.filesystem;
 
+import dan200.computercraft.api.filesystem.FileOperationException;
 import dan200.computercraft.api.filesystem.IMount;
 
 import javax.annotation.Nonnull;
@@ -44,7 +45,7 @@ public class EmptyMount implements IMount
     @Deprecated
     public InputStream openForRead( @Nonnull String path ) throws IOException
     {
-        throw new IOException( "/" + path + ": No such file" );
+        throw new FileOperationException( path, "No such file" );
     }
 
     @Nonnull
@@ -52,6 +53,6 @@ public class EmptyMount implements IMount
     @Deprecated
     public ReadableByteChannel openChannelForRead( @Nonnull String path ) throws IOException
     {
-        throw new IOException( "/" + path + ": No such file" );
+        throw new FileOperationException( path, "No such file" );
     }
 }

src/main/java/dan200/computercraft/core/filesystem/FileMount.java

@@ -7,6 +7,7 @@
 package dan200.computercraft.core.filesystem;
 
 import com.google.common.collect.Sets;
+import dan200.computercraft.api.filesystem.FileOperationException;
 import dan200.computercraft.api.filesystem.IWritableMount;
 
 import javax.annotation.Nonnull;
@@ -167,12 +168,12 @@ public class FileMount implements IWritableMount
     {
         if( !created() )
         {
-            if( !path.isEmpty() ) throw new IOException( "/" + path + ": Not a directory" );
+            if( !path.isEmpty() ) throw new FileOperationException( path, "Not a directory" );
             return;
         }
 
         File file = getRealPath( path );
-        if( !file.exists() || !file.isDirectory() ) throw new IOException( "/" + path + ": Not a directory" );
+        if( !file.exists() || !file.isDirectory() ) throw new FileOperationException( path, "Not a directory" );
 
         String[] paths = file.list();
         for( String subPath : paths )
@@ -194,7 +195,7 @@ public class FileMount implements IWritableMount
             if( file.exists() ) return file.isDirectory() ? 0 : file.length();
         }
 
-        throw new IOException( "/" + path + ": No such file" );
+        throw new FileOperationException( path, "No such file" );
     }
 
     @Nonnull
@@ -208,7 +209,7 @@ public class FileMount implements IWritableMount
             if( file.exists() && !file.isDirectory() ) return new FileInputStream( file );
         }
 
-        throw new IOException( "/" + path + ": No such file" );
+        throw new FileOperationException( path, "No such file" );
     }
 
     @Nonnull
@@ -221,7 +222,7 @@ public class FileMount implements IWritableMount
             if( file.exists() && !file.isDirectory() ) return FileChannel.open( file.toPath(), READ_OPTIONS );
         }
 
-        throw new IOException( "/" + path + ": No such file" );
+        throw new FileOperationException( path, "No such file" );
     }
 
     // IWritableMount implementation
@@ -233,7 +234,7 @@ public class FileMount implements IWritableMount
         File file = getRealPath( path );
         if( file.exists() )
         {
-            if( !file.isDirectory() ) throw new IOException( "/" + path + ": File exists" );
+            if( !file.isDirectory() ) throw new FileOperationException( path, "File exists" );
             return;
         }
 
@@ -247,7 +248,7 @@ public class FileMount implements IWritableMount
 
         if( getRemainingSpace() < dirsToCreate * MINIMUM_FILE_SIZE )
         {
-            throw new IOException( "/" + path + ": Out of space" );
+            throw new FileOperationException( path, "Out of space" );
         }
 
         if( file.mkdirs() )
@@ -256,14 +257,14 @@ public class FileMount implements IWritableMount
         }
         else
         {
-            throw new IOException( "/" + path + ": Access denied" );
+            throw new FileOperationException( path, "Access denied" );
         }
     }
 
     @Override
     public void delete( @Nonnull String path ) throws IOException
     {
-        if( path.isEmpty() ) throw new IOException( "/" + path + ": Access denied" );
+        if( path.isEmpty() ) throw new FileOperationException( path, "Access denied" );
 
         if( created() )
         {
@@ -319,7 +320,7 @@ public class FileMount implements IWritableMount
     {
         create();
         File file = getRealPath( path );
-        if( file.exists() && file.isDirectory() ) throw new IOException( "/" + path + ": Cannot write to directory" );
+        if( file.exists() && file.isDirectory() ) throw new FileOperationException( path, "Cannot write to directory" );
 
         if( file.exists() )
         {
@@ -327,7 +328,7 @@ public class FileMount implements IWritableMount
         }
         else if( getRemainingSpace() < MINIMUM_FILE_SIZE )
         {
-            throw new IOException( "/" + path + ": Out of space" );
+            throw new FileOperationException( path, "Out of space" );
         }
         m_usedSpace += MINIMUM_FILE_SIZE;
 
@@ -340,12 +341,12 @@ public class FileMount implements IWritableMount
     {
         if( !created() )
         {
-            throw new IOException( "/" + path + ": No such file" );
+            throw new FileOperationException( path, "No such file" );
         }
 
         File file = getRealPath( path );
-        if( !file.exists() ) throw new IOException( "/" + path + ": No such file" );
-        if( file.isDirectory() ) throw new IOException( "/" + path + ": Cannot write to directory" );
+        if( !file.exists() ) throw new FileOperationException( path, "No such file" );
+        if( file.isDirectory() ) throw new FileOperationException( path, "Cannot write to directory" );
 
         // Allowing seeking when appending is not recommended, so we use a separate channel.
         return new WritableCountingChannel(

src/main/java/dan200/computercraft/core/filesystem/FileSystem.java

@@ -8,6 +8,7 @@ package dan200.computercraft.core.filesystem;
 
 import com.google.common.io.ByteStreams;
 import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.api.filesystem.FileOperationException;
 import dan200.computercraft.api.filesystem.IFileSystem;
 import dan200.computercraft.api.filesystem.IMount;
 import dan200.computercraft.api.filesystem.IWritableMount;
@@ -45,7 +46,7 @@ public class FileSystem
             m_writableMount = null;
         }
 
-        public MountWrapper( String label, String location, IWritableMount mount )
+        MountWrapper( String label, String location, IWritableMount mount )
         {
             this( label, location, (IMount) mount );
             m_writableMount = mount;
@@ -107,7 +108,7 @@ public class FileSystem
             }
             catch( IOException e )
             {
-                throw new FileSystemException( e.getMessage() );
+                throw localExceptionOf( e );
             }
         }
 
@@ -122,12 +123,12 @@ public class FileSystem
                 }
                 else
                 {
-                    throw new FileSystemException( "/" + path + ": Not a directory" );
+                    throw localExceptionOf( path, "Not a directory" );
                 }
             }
             catch( IOException e )
             {
-                throw new FileSystemException( e.getMessage() );
+                throw localExceptionOf( e );
             }
         }
 
@@ -149,12 +150,12 @@ public class FileSystem
                 }
                 else
                 {
-                    throw new FileSystemException( "/" + path + ": No such file" );
+                    throw localExceptionOf( path, "No such file" );
                 }
             }
             catch( IOException e )
             {
-                throw new FileSystemException( e.getMessage() );
+                throw localExceptionOf( e );
             }
         }
 
@@ -169,12 +170,12 @@ public class FileSystem
                 }
                 else
                 {
-                    throw new FileSystemException( "/" + path + ": No such file" );
+                    throw localExceptionOf( path, "No such file" );
                 }
             }
             catch( IOException e )
             {
-                throw new FileSystemException( e.getMessage() );
+                throw localExceptionOf( e );
             }
         }
 
@@ -182,19 +183,14 @@ public class FileSystem
 
         public void makeDirectory( String path ) throws FileSystemException
         {
-            if( m_writableMount == null )
-            {
-                throw new FileSystemException( "/" + path + ": Access denied" );
-            }
+            if( m_writableMount == null ) throw exceptionOf( path, "Access denied" );
+
+            path = toLocal( path );
             try
             {
-                path = toLocal( path );
                 if( m_mount.exists( path ) )
                 {
-                    if( !m_mount.isDirectory( path ) )
-                    {
-                        throw new FileSystemException( "/" + path + ": File exists" );
-                    }
+                    if( !m_mount.isDirectory( path ) ) throw localExceptionOf( path, "File exists" );
                 }
                 else
                 {
@@ -203,16 +199,14 @@ public class FileSystem
             }
             catch( IOException e )
             {
-                throw new FileSystemException( e.getMessage() );
+                throw localExceptionOf( e );
             }
         }
 
         public void delete( String path ) throws FileSystemException
         {
-            if( m_writableMount == null )
-            {
-                throw new FileSystemException( "/" + path + ": Access denied" );
-            }
+            if( m_writableMount == null ) throw exceptionOf( path, "Access denied" );
+
             try
             {
                 path = toLocal( path );
@@ -227,22 +221,20 @@ public class FileSystem
             }
             catch( IOException e )
             {
-                throw new FileSystemException( e.getMessage() );
+                throw localExceptionOf( e );
             }
         }
 
         public WritableByteChannel openForWrite( String path ) throws FileSystemException
         {
-            if( m_writableMount == null )
-            {
-                throw new FileSystemException( "/" + path + ": Access denied" );
-            }
+            if( m_writableMount == null ) throw exceptionOf( path, "Access denied" );
+
+            path = toLocal( path );
             try
             {
-                path = toLocal( path );
                 if( m_mount.exists( path ) && m_mount.isDirectory( path ) )
                 {
-                    throw new FileSystemException( "/" + path + ": Cannot write to directory" );
+                    throw localExceptionOf( path, "Cannot write to directory" );
                 }
                 else
                 {
@@ -263,19 +255,17 @@ public class FileSystem
             }
             catch( IOException e )
             {
-                throw new FileSystemException( e.getMessage() );
+                throw localExceptionOf( e );
             }
         }
 
         public WritableByteChannel openForAppend( String path ) throws FileSystemException
         {
-            if( m_writableMount == null )
-            {
-                throw new FileSystemException( "/" + path + ": Access denied" );
-            }
+            if( m_writableMount == null ) throw exceptionOf( path, "Access denied" );
+
+            path = toLocal( path );
             try
             {
-                path = toLocal( path );
                 if( !m_mount.exists( path ) )
                 {
                     if( !path.isEmpty() )
@@ -290,7 +280,7 @@ public class FileSystem
                 }
                 else if( m_mount.isDirectory( path ) )
                 {
-                    throw new FileSystemException( "/" + path + ": Cannot write to directory" );
+                    throw localExceptionOf( path, "Cannot write to directory" );
                 }
                 else
                 {
@@ -303,16 +293,36 @@ public class FileSystem
             }
             catch( IOException e )
             {
-                throw new FileSystemException( e.getMessage() );
+                throw localExceptionOf( e );
             }
         }
 
-        // private members
-
         private String toLocal( String path )
         {
             return FileSystem.toLocal( path, m_location );
         }
+
+        private FileSystemException localExceptionOf( IOException e )
+        {
+            if( !m_location.isEmpty() && e instanceof FileOperationException )
+            {
+                FileOperationException ex = (FileOperationException) e;
+                if( ex.getFilename() != null ) return localExceptionOf( ex.getFilename(), ex.getMessage() );
+            }
+
+            return new FileSystemException( e.getMessage() );
+        }
+
+        private FileSystemException localExceptionOf( String path, String message )
+        {
+            if( !m_location.isEmpty() ) path = path.isEmpty() ? m_location : m_location + "/" + path;
+            return exceptionOf( path, message );
+        }
+
+        private static FileSystemException exceptionOf( String path, String message )
+        {
+            return new FileSystemException( "/" + path + ": " + message );
+        }
     }
 
     private final FileSystemWrapperMount m_wrapper = new FileSystemWrapperMount( this );
@@ -769,7 +779,7 @@ public class FileSystem
 
         // Clean the path or illegal characters.
         final char[] specialChars = new char[] {
-            '"', ':', '<', '>', '?', '|' // Sorted by ascii value (important)
+            '"', ':', '<', '>', '?', '|', // Sorted by ascii value (important)
         };
 
         StringBuilder cleanName = new StringBuilder();

src/main/java/dan200/computercraft/core/filesystem/JarMount.java

@@ -9,6 +9,7 @@ package dan200.computercraft.core.filesystem;
 import com.google.common.cache.Cache;
 import com.google.common.cache.CacheBuilder;
 import com.google.common.io.ByteStreams;
+import dan200.computercraft.api.filesystem.FileOperationException;
 import dan200.computercraft.api.filesystem.IMount;
 import dan200.computercraft.core.apis.handles.ArrayByteChannel;
 import dan200.computercraft.shared.util.IoUtil;
@@ -69,7 +70,7 @@ public class JarMount implements IMount
         // Cleanup any old mounts. It's unlikely that there will be any, but it's best to be safe.
         cleanup();
 
-        if( !jarFile.exists() || jarFile.isDirectory() ) throw new FileNotFoundException();
+        if( !jarFile.exists() || jarFile.isDirectory() ) throw new FileNotFoundException( "Cannot find " + jarFile );
 
         // Open the zip file
         try
@@ -85,14 +86,14 @@ public class JarMount implements IMount
         if( zip.getEntry( subPath ) == null )
         {
             zip.close();
-            throw new IOException( "Zip does not contain path" );
+            throw new FileNotFoundException( "Zip does not contain path" );
         }
 
         // We now create a weak reference to this mount. This is automatically added to the appropriate queue.
         new MountReference( this );
 
         // Read in all the entries
-        root = new FileEntry( "" );
+        root = new FileEntry();
         Enumeration<? extends ZipEntry> zipEntries = zip.entries();
         while( zipEntries.hasMoreElements() )
         {
@@ -139,7 +140,7 @@ public class JarMount implements IMount
             FileEntry nextEntry = lastEntry.children.get( part );
             if( nextEntry == null || !nextEntry.isDirectory() )
             {
-                lastEntry.children.put( part, nextEntry = new FileEntry( part ) );
+                lastEntry.children.put( part, nextEntry = new FileEntry() );
             }
 
             lastEntry = nextEntry;
@@ -166,7 +167,7 @@ public class JarMount implements IMount
     public void list( @Nonnull String path, @Nonnull List<String> contents ) throws IOException
     {
         FileEntry file = get( path );
-        if( file == null || !file.isDirectory() ) throw new IOException( "/" + path + ": Not a directory" );
+        if( file == null || !file.isDirectory() ) throw new FileOperationException( path, "Not a directory" );
 
         file.list( contents );
     }
@@ -176,7 +177,7 @@ public class JarMount implements IMount
     {
         FileEntry file = get( path );
         if( file != null ) return file.size;
-        throw new IOException( "/" + path + ": No such file" );
+        throw new FileOperationException( path, "No such file" );
     }
 
     @Nonnull
@@ -218,22 +219,15 @@ public class JarMount implements IMount
             }
         }
 
-        throw new IOException( "/" + path + ": No such file" );
+        throw new FileOperationException( path, "No such file" );
     }
 
     private static class FileEntry
     {
-        final String name;
-
         String path;
         long size;
         Map<String, FileEntry> children;
 
-        FileEntry( String name )
-        {
-            this.name = name;
-        }
-
         void setup( ZipEntry entry )
         {
             path = entry.getName();

src/main/java/dan200/computercraft/core/filesystem/ResourceMount.java

@@ -14,7 +14,6 @@ import dan200.computercraft.core.apis.handles.ArrayByteChannel;
 import net.minecraft.resources.IReloadableResourceManager;
 import net.minecraft.resources.IResource;
 import net.minecraft.resources.IResourceManager;
-import net.minecraft.resources.IResourceManagerReloadListener;
 import net.minecraft.util.ResourceLocation;
 import net.minecraftforge.resource.IResourceType;
 import net.minecraftforge.resource.ISelectiveResourceReloadListener;
@@ -171,7 +170,7 @@ public class ResourceMount implements IMount
                 {
                     total += read;
                     read = s.read( TEMP_BUFFER );
-                } while( read > 0 );
+                } while ( read > 0 );
 
                 return file.size = total;
             }
@@ -241,7 +240,7 @@ public class ResourceMount implements IMount
     }
 
     /**
-     * A {@link IResourceManagerReloadListener} which reloads any associated mounts.
+     * A {@link ISelectiveResourceReloadListener} which reloads any associated mounts.
      *
      * While people should really be keeping a permanent reference to this, some people construct it every
      * method call, so let's make this as small as possible.

src/main/java/dan200/computercraft/core/lua/CobaltLuaMachine.java

@@ -242,7 +242,7 @@ public class CobaltLuaMachine implements ILuaMachine
                         }
                         catch( InterruptedException e )
                         {
-                            throw new OrphanedThread();
+                            throw new InterruptedError( e );
                         }
                         catch( LuaException e )
                         {
@@ -550,7 +550,7 @@ public class CobaltLuaMachine implements ILuaMachine
                 {
                     if( ComputerCraft.logPeripheralErrors ) ComputerCraft.log.error( "Error running task", t );
                     m_computer.queueEvent( "task_complete", new Object[] {
-                        taskID, false, "Java Exception Thrown: " + t
+                        taskID, false, "Java Exception Thrown: " + t,
                     } );
                 }
             };

src/main/java/dan200/computercraft/core/terminal/TextBuffer.java

@@ -8,7 +8,7 @@ package dan200.computercraft.core.terminal;
 
 public class TextBuffer
 {
-    public char[] m_text;
+    private final char[] m_text;
 
     public TextBuffer( char c, int length )
     {

src/main/java/dan200/computercraft/shared/BundledRedstone.java

@@ -6,7 +6,6 @@
 
 package dan200.computercraft.shared;
 
-import com.google.common.base.Preconditions;
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.api.redstone.IBundledRedstoneProvider;
 import dan200.computercraft.shared.common.DefaultBundledRedstoneProvider;
@@ -16,6 +15,7 @@ import net.minecraft.world.World;
 
 import javax.annotation.Nonnull;
 import java.util.LinkedHashSet;
+import java.util.Objects;
 import java.util.Set;
 
 public final class BundledRedstone
@@ -26,7 +26,7 @@ public final class BundledRedstone
 
     public static synchronized void register( @Nonnull IBundledRedstoneProvider provider )
     {
-        Preconditions.checkNotNull( provider, "provider cannot be null" );
+        Objects.requireNonNull( provider, "provider cannot be null" );
         providers.add( provider );
     }
 

src/main/java/dan200/computercraft/shared/Config.java

@@ -44,8 +44,8 @@ public final class Config
     private static ConfigValue<Boolean> logComputerErrors;
 
     private static ConfigValue<Integer> computerThreads;
-    private static ConfigValue<Long> maxMainGlobalTime;
-    private static ConfigValue<Long> maxMainComputerTime;
+    private static ConfigValue<Integer> maxMainGlobalTime;
+    private static ConfigValue<Integer> maxMainComputerTime;
 
     private static ConfigValue<Boolean> httpEnabled;
     private static ConfigValue<Boolean> httpWebsocketEnabled;
@@ -54,8 +54,8 @@ public final class Config
 
     private static ConfigValue<Integer> httpTimeout;
     private static ConfigValue<Integer> httpMaxRequests;
-    private static ConfigValue<Long> httpMaxDownload;
-    private static ConfigValue<Long> httpMaxUpload;
+    private static ConfigValue<Integer> httpMaxDownload;
+    private static ConfigValue<Integer> httpMaxUpload;
     private static ConfigValue<Integer> httpMaxWebsockets;
     private static ConfigValue<Integer> httpMaxWebsocketMessage;
 
@@ -134,13 +134,13 @@ public final class Config
                 .comment( "The maximum time that can be spent executing tasks in a single tick, in milliseconds.\n" +
                     "Note, we will quite possibly go over this limit, as there's no way to tell how long a will take " +
                     "- this aims to be the upper bound of the average time." )
-                .defineInRange( "max_main_global_time", TimeUnit.NANOSECONDS.toMillis( ComputerCraft.maxMainGlobalTime ), 1, Long.MAX_VALUE );
+                .defineInRange( "max_main_global_time", (int) TimeUnit.NANOSECONDS.toMillis( ComputerCraft.maxMainGlobalTime ), 1, Integer.MAX_VALUE );
 
             maxMainComputerTime = builder
                 .comment( "The ideal maximum time a computer can execute for in a tick, in milliseconds.\n" +
                     "Note, we will quite possibly go over this limit, as there's no way to tell how long a will take " +
                     "- this aims to be the upper bound of the average time." )
-                .defineInRange( "max_main_computer_time", TimeUnit.NANOSECONDS.toMillis( ComputerCraft.maxMainComputerTime ), 1, Long.MAX_VALUE );
+                .defineInRange( "max_main_computer_time", (int) TimeUnit.NANOSECONDS.toMillis( ComputerCraft.maxMainComputerTime ), 1, Integer.MAX_VALUE );
 
             builder.pop();
         }
@@ -180,11 +180,11 @@ public final class Config
 
             httpMaxDownload = builder
                 .comment( "The maximum size (in bytes) that a computer can download in a single request. Note that responses may receive more data than allowed, but this data will not be returned to the client." )
-                .defineInRange( "max_download", ComputerCraft.httpMaxDownload, 0, Long.MAX_VALUE );
+                .defineInRange( "max_download", (int) ComputerCraft.httpMaxDownload, 0, Integer.MAX_VALUE );
 
             httpMaxUpload = builder
                 .comment( "The maximum size (in bytes) that a computer can upload in a single request. This includes headers and POST text." )
-                .defineInRange( "max_upload", ComputerCraft.httpMaxUpload, 0, Long.MAX_VALUE );
+                .defineInRange( "max_upload", (int) ComputerCraft.httpMaxUpload, 0, Integer.MAX_VALUE );
 
             httpMaxWebsockets = builder
                 .comment( "The number of websockets a computer can have open at one time. Set to 0 for unlimited." )

src/main/java/dan200/computercraft/shared/command/CommandComputerCraft.java

@@ -11,8 +11,8 @@ import com.mojang.brigadier.arguments.StringArgumentType;
 import com.mojang.brigadier.exceptions.CommandSyntaxException;
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.api.peripheral.IPeripheral;
-import dan200.computercraft.core.apis.IAPIEnvironment;
 import dan200.computercraft.core.computer.Computer;
+import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.core.tracking.ComputerTracker;
 import dan200.computercraft.core.tracking.Tracking;
 import dan200.computercraft.core.tracking.TrackingContext;
@@ -118,12 +118,12 @@ public final class CommandComputerCraft
                         table.row( header( "Position" ), linkPosition( context.getSource(), computer ) );
                         table.row( header( "Family" ), text( computer.getFamily().toString() ) );
 
-                        for( int i = 0; i < 6; i++ )
+                        for( ComputerSide side : ComputerSide.values() )
                         {
-                            IPeripheral peripheral = computer.getPeripheral( i );
+                            IPeripheral peripheral = computer.getPeripheral( side );
                             if( peripheral != null )
                             {
-                                table.row( header( "Peripheral " + IAPIEnvironment.SIDE_NAMES[i] ), text( peripheral.getType() ) );
+                                table.row( header( "Peripheral " + side.getName() ), text( peripheral.getType() ) );
                             }
                         }
 

src/main/java/dan200/computercraft/shared/command/Exceptions.java

@@ -16,7 +16,7 @@ public final class Exceptions
     public static final DynamicCommandExceptionType COMPUTER_ARG_NONE = translated1( "argument.computercraft.computer.no_matching" );
     public static final Dynamic2CommandExceptionType COMPUTER_ARG_MANY = translated2( "argument.computercraft.computer.many_matching" );
 
-    public static final DynamicCommandExceptionType TRACKING_FIELD_ARG_NONE = translated1( "argument.computercraft.tacking_field.no_field" );
+    public static final DynamicCommandExceptionType TRACKING_FIELD_ARG_NONE = translated1( "argument.computercraft.tracking_field.no_field" );
 
     static final SimpleCommandExceptionType NOT_TRACKING_EXCEPTION = translated( "commands.computercraft.track.stop.not_enabled" );
     static final SimpleCommandExceptionType NO_TIMINGS_EXCEPTION = translated( "commands.computercraft.track.dump.no_timings" );

src/main/java/dan200/computercraft/shared/common/BlockGeneric.java

@@ -7,7 +7,6 @@
 package dan200.computercraft.shared.common;
 
 import net.minecraft.block.Block;
-import net.minecraft.block.ITileEntityProvider;
 import net.minecraft.block.state.IBlockState;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.tileentity.TileEntity;
@@ -23,7 +22,7 @@ import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 import java.util.Random;
 
-public abstract class BlockGeneric extends Block implements ITileEntityProvider
+public abstract class BlockGeneric extends Block
 {
     private final TileEntityType<? extends TileGeneric> type;
 
@@ -55,7 +54,6 @@ public abstract class BlockGeneric extends Block implements ITileEntityProvider
 
     @Override
     @Deprecated
-    @SuppressWarnings( "deprecation" )
     public final void neighborChanged( IBlockState state, World world, BlockPos pos, Block neighbourBlock, BlockPos neighbourPos )
     {
         TileEntity tile = world.getTileEntity( pos );
@@ -77,9 +75,15 @@ public abstract class BlockGeneric extends Block implements ITileEntityProvider
         if( te instanceof TileGeneric ) ((TileGeneric) te).blockTick();
     }
 
+    @Override
+    public boolean hasTileEntity( IBlockState state )
+    {
+        return true;
+    }
+
     @Nullable
     @Override
-    public TileEntity createNewTileEntity( @Nonnull IBlockReader world )
+    public TileEntity createTileEntity( @Nonnull IBlockState state, @Nonnull IBlockReader world )
     {
         return type.create();
     }

src/main/java/dan200/computercraft/shared/computer/apis/CommandAPI.java

@@ -49,9 +49,7 @@ public class CommandAPI implements ILuaAPI
     @Override
     public String[] getNames()
     {
-        return new String[] {
-            "commands"
-        };
+        return new String[] { "commands" };
     }
 
     @Nonnull
@@ -64,7 +62,7 @@ public class CommandAPI implements ILuaAPI
             "list",
             "getBlockPosition",
             "getBlockInfos",
-            "getBlockInfo"
+            "getBlockInfo",
         };
     }
 

src/main/java/dan200/computercraft/shared/computer/blocks/BlockComputerBase.java

@@ -6,6 +6,7 @@
 
 package dan200.computercraft.shared.computer.blocks;
 
+import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.shared.common.BlockGeneric;
 import dan200.computercraft.shared.common.IBundledRedstoneBlock;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
@@ -65,9 +66,8 @@ public abstract class BlockComputerBase<T extends TileComputerBase> extends Bloc
         ServerComputer computer = computerEntity.getServerComputer();
         if( computer == null ) return 0;
 
-        EnumFacing localSide = computerEntity.remapToLocalSide( incomingSide.getOpposite() );
-        return computerEntity.isRedstoneBlockedOnSide( localSide ) ? 0 :
-            computer.getRedstoneOutput( localSide.getIndex() );
+        ComputerSide localSide = computerEntity.remapToLocalSide( incomingSide.getOpposite() );
+        return computer.getRedstoneOutput( localSide );
     }
 
     @Nonnull
@@ -88,11 +88,7 @@ public abstract class BlockComputerBase<T extends TileComputerBase> extends Bloc
     @Override
     public boolean getBundledRedstoneConnectivity( World world, BlockPos pos, EnumFacing side )
     {
-        TileEntity entity = world.getTileEntity( pos );
-        if( !(entity instanceof TileComputerBase) ) return false;
-
-        TileComputerBase computerEntity = (TileComputerBase) entity;
-        return !computerEntity.isRedstoneBlockedOnSide( computerEntity.remapToLocalSide( side ) );
+        return true;
     }
 
     @Override
@@ -105,9 +101,8 @@ public abstract class BlockComputerBase<T extends TileComputerBase> extends Bloc
         ServerComputer computer = computerEntity.getServerComputer();
         if( computer == null ) return 0;
 
-        EnumFacing localSide = computerEntity.remapToLocalSide( side );
-        return computerEntity.isRedstoneBlockedOnSide( localSide ) ? 0 :
-            computer.getBundledRedstoneOutput( localSide.getIndex() );
+        ComputerSide localSide = computerEntity.remapToLocalSide( side );
+        return computer.getBundledRedstoneOutput( localSide );
     }
 
     @Nonnull

src/main/java/dan200/computercraft/shared/computer/blocks/TileComputer.java

@@ -7,6 +7,7 @@
 package dan200.computercraft.shared.computer.blocks;
 
 import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
 import dan200.computercraft.shared.computer.core.ComputerState;
 import dan200.computercraft.shared.computer.core.ServerComputer;
@@ -95,8 +96,12 @@ public class TileComputer extends TileComputerBase
     }
 
     @Override
-    protected EnumFacing remapLocalSide( EnumFacing localSide )
+    protected ComputerSide remapLocalSide( ComputerSide localSide )
     {
-        return localSide.getAxis() == EnumFacing.Axis.X ? localSide.getOpposite() : localSide;
+        // For legacy reasons, computers invert the meaning of "left" and "right". A computer's front is facing
+        // towards you, but a turtle's front is facing the other way.
+        if( localSide == ComputerSide.RIGHT ) return ComputerSide.LEFT;
+        if( localSide == ComputerSide.LEFT ) return ComputerSide.RIGHT;
+        return localSide;
     }
 }

src/main/java/dan200/computercraft/shared/computer/blocks/TileComputerBase.java

@@ -9,6 +9,7 @@ package dan200.computercraft.shared.computer.blocks;
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.api.peripheral.IPeripheralTile;
+import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.shared.BundledRedstone;
 import dan200.computercraft.shared.Peripherals;
 import dan200.computercraft.shared.common.TileGeneric;
@@ -19,7 +20,10 @@ import dan200.computercraft.shared.computer.core.ServerComputer;
 import dan200.computercraft.shared.util.DirectionUtil;
 import dan200.computercraft.shared.util.RedstoneUtil;
 import joptsimple.internal.Strings;
+import net.minecraft.block.BlockRedstoneWire;
+import net.minecraft.block.state.IBlockState;
 import net.minecraft.entity.player.EntityPlayer;
+import net.minecraft.init.Blocks;
 import net.minecraft.init.Items;
 import net.minecraft.item.ItemStack;
 import net.minecraft.nbt.NBTTagCompound;
@@ -31,6 +35,7 @@ import net.minecraft.util.ITickable;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.text.ITextComponent;
 import net.minecraft.util.text.TextComponentString;
+import net.minecraft.world.World;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -198,24 +203,19 @@ public abstract class TileComputerBase extends TileGeneric implements IComputerT
         m_on = m_startOn = nbt.getBoolean( NBT_ON );
     }
 
-    protected boolean isPeripheralBlockedOnSide( EnumFacing localSide )
-    {
-        return false;
-    }
-
-    protected boolean isRedstoneBlockedOnSide( EnumFacing localSide )
+    protected boolean isPeripheralBlockedOnSide( ComputerSide localSide )
     {
         return false;
     }
 
     protected abstract EnumFacing getDirection();
 
-    protected EnumFacing remapToLocalSide( EnumFacing globalSide )
+    protected ComputerSide remapToLocalSide( EnumFacing globalSide )
     {
         return remapLocalSide( DirectionUtil.toLocal( getDirection(), globalSide ) );
     }
 
-    protected EnumFacing remapLocalSide( EnumFacing localSide )
+    protected ComputerSide remapLocalSide( ComputerSide localSide )
     {
         return localSide;
     }
@@ -223,18 +223,36 @@ public abstract class TileComputerBase extends TileGeneric implements IComputerT
     private void updateSideInput( ServerComputer computer, EnumFacing dir, BlockPos offset )
     {
         EnumFacing offsetSide = dir.getOpposite();
-        EnumFacing localDir = remapToLocalSide( dir );
-        if( !isRedstoneBlockedOnSide( localDir ) )
-        {
-            computer.setRedstoneInput( localDir.getIndex(), getWorld().getRedstonePower( offset, dir ) );
-            computer.setBundledRedstoneInput( localDir.getIndex(), BundledRedstone.getOutput( getWorld(), offset, offsetSide ) );
-        }
+        ComputerSide localDir = remapToLocalSide( dir );
+
+        computer.setRedstoneInput( localDir, getRedstoneInput( world, offset, dir ) );
+        computer.setBundledRedstoneInput( localDir, BundledRedstone.getOutput( getWorld(), offset, offsetSide ) );
         if( !isPeripheralBlockedOnSide( localDir ) )
         {
-            computer.setPeripheral( localDir.getIndex(), Peripherals.getPeripheral( getWorld(), offset, offsetSide ) );
+            computer.setPeripheral( localDir, Peripherals.getPeripheral( getWorld(), offset, offsetSide ) );
         }
     }
 
+    /**
+     * Gets the redstone input for an adjacent block
+     *
+     * @param world The world we exist in
+     * @param pos   The position of the neighbour
+     * @param side  The side we are reading from
+     * @return The effective redstone power
+     * @see net.minecraft.block.BlockRedstoneDiode#calculateInputStrength(World, BlockPos, IBlockState)
+     */
+    protected static int getRedstoneInput( World world, BlockPos pos, EnumFacing side )
+    {
+        int power = world.getRedstonePower( pos, side );
+        if( power >= 15 ) return power;
+
+        IBlockState neighbour = world.getBlockState( pos );
+        return neighbour.getBlock() == Blocks.REDSTONE_WIRE
+            ? Math.max( power, neighbour.get( BlockRedstoneWire.POWER ) )
+            : power;
+    }
+
     public void updateInput()
     {
         if( getWorld() == null || getWorld().isRemote ) return;
@@ -257,7 +275,6 @@ public abstract class TileComputerBase extends TileGeneric implements IComputerT
         ServerComputer computer = getServerComputer();
         if( computer == null ) return;
 
-        // Find the appropriate side and update.
         BlockPos pos = computer.getPosition();
         for( EnumFacing dir : DirectionUtil.FACINGS )
         {
@@ -268,6 +285,9 @@ public abstract class TileComputerBase extends TileGeneric implements IComputerT
                 break;
             }
         }
+
+        // If the position is not any adjacent one, update all inputs.
+        updateInput();
     }
 
     public void updateOutput()

src/main/java/dan200/computercraft/shared/computer/core/ComputerRegistry.java

@@ -11,9 +11,9 @@ import java.util.HashMap;
 import java.util.Map;
 import java.util.Random;
 
-public class ComputerRegistry<TComputer extends IComputer>
+public class ComputerRegistry<T extends IComputer>
 {
-    private Map<Integer, TComputer> m_computers;
+    private Map<Integer, T> m_computers;
     private int m_nextUnusedInstanceID;
     private int m_sessionID;
 
@@ -33,12 +33,12 @@ public class ComputerRegistry<TComputer extends IComputer>
         return m_nextUnusedInstanceID++;
     }
 
-    public Collection<TComputer> getComputers()
+    public Collection<T> getComputers()
     {
         return m_computers.values();
     }
 
-    public TComputer get( int instanceID )
+    public T get( int instanceID )
     {
         if( instanceID >= 0 )
         {
@@ -55,7 +55,7 @@ public class ComputerRegistry<TComputer extends IComputer>
         return m_computers.containsKey( instanceID );
     }
 
-    public void add( int instanceID, TComputer computer )
+    public void add( int instanceID, T computer )
     {
         if( m_computers.containsKey( instanceID ) )
         {

src/main/java/dan200/computercraft/shared/computer/core/ServerComputer.java

@@ -14,6 +14,7 @@ import dan200.computercraft.api.lua.ILuaAPI;
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.core.apis.IAPIEnvironment;
 import dan200.computercraft.core.computer.Computer;
+import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.core.computer.IComputerEnvironment;
 import dan200.computercraft.shared.common.ServerTerminal;
 import dan200.computercraft.shared.network.NetworkHandler;
@@ -172,10 +173,14 @@ public class ServerComputer extends ServerTerminal implements IComputer, IComput
             // Send terminal state to clients who are currently interacting with the computer.
             MinecraftServer server = ServerLifecycleHooks.getCurrentServer();
 
-            NetworkMessage packet = createTerminalPacket();
+            NetworkMessage packet = null;
             for( EntityPlayer player : server.getPlayerList().getPlayers() )
             {
-                if( isInteracting( player ) ) NetworkHandler.sendToPlayer( player, packet );
+                if( isInteracting( player ) )
+                {
+                    if( packet == null ) packet = createTerminalPacket();
+                    NetworkHandler.sendToPlayer( player, packet );
+                }
             }
         }
     }
@@ -261,22 +266,22 @@ public class ServerComputer extends ServerTerminal implements IComputer, IComput
         m_computer.queueEvent( event, arguments );
     }
 
-    public int getRedstoneOutput( int side )
+    public int getRedstoneOutput( ComputerSide side )
     {
         return m_computer.getEnvironment().getExternalRedstoneOutput( side );
     }
 
-    public void setRedstoneInput( int side, int level )
+    public void setRedstoneInput( ComputerSide side, int level )
     {
         m_computer.getEnvironment().setRedstoneInput( side, level );
     }
 
-    public int getBundledRedstoneOutput( int side )
+    public int getBundledRedstoneOutput( ComputerSide side )
     {
         return m_computer.getEnvironment().getExternalBundledRedstoneOutput( side );
     }
 
-    public void setBundledRedstoneInput( int side, int combination )
+    public void setBundledRedstoneInput( ComputerSide side, int combination )
     {
         m_computer.getEnvironment().setBundledRedstoneInput( side, combination );
     }
@@ -286,12 +291,12 @@ public class ServerComputer extends ServerTerminal implements IComputer, IComput
         m_computer.addApi( api );
     }
 
-    public void setPeripheral( int side, IPeripheral peripheral )
+    public void setPeripheral( ComputerSide side, IPeripheral peripheral )
     {
         m_computer.getEnvironment().setPeripheral( side, peripheral );
     }
 
-    public IPeripheral getPeripheral( int side )
+    public IPeripheral getPeripheral( ComputerSide side )
     {
         return m_computer.getEnvironment().getPeripheral( side );
     }

src/main/java/dan200/computercraft/shared/integration/charset/BundledCapabilityProvider.java

@@ -1,9 +1,8 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2018. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.shared.integration.charset;
 
 import dan200.computercraft.shared.common.TileGeneric;

src/main/java/dan200/computercraft/shared/integration/charset/BundledRedstoneProvider.java

@@ -1,9 +1,8 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2018. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.shared.integration.charset;
 
 import dan200.computercraft.api.redstone.IBundledRedstoneProvider;

src/main/java/dan200/computercraft/shared/integration/charset/IntegrationCharset.java

@@ -1,9 +1,8 @@
 /*
  * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2018. Do not distribute without permission.
+ * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
  * Send enquiries to dratcliffe@gmail.com
  */
-
 package dan200.computercraft.shared.integration.charset;
 
 import dan200.computercraft.ComputerCraft;

src/main/java/dan200/computercraft/shared/integration/mcmp/MCMPIntegration.java

@@ -10,8 +10,10 @@ import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.api.ComputerCraftAPI;
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.api.peripheral.IPeripheralTile;
+import dan200.computercraft.shared.peripheral.common.TilePeripheralBase;
 import dan200.computercraft.shared.peripheral.modem.wireless.TileAdvancedModem;
 import dan200.computercraft.shared.peripheral.modem.wireless.TileWirelessModem;
+import dan200.computercraft.shared.peripheral.monitor.TileMonitor;
 import mcmultipart.api.addon.IMCMPAddon;
 import mcmultipart.api.addon.MCMPAddon;
 import mcmultipart.api.container.IMultipartContainer;
@@ -52,7 +54,7 @@ public class MCMPIntegration implements IMCMPAddon
     public void registerParts( IMultipartRegistry registry )
     {
         // Setup all parts
-        register( registry, ComputerCraft.Blocks.peripheral, new PartNormalModem() );
+        register( registry, ComputerCraft.Blocks.peripheral, new PartPeripheral() );
         register( registry, ComputerCraft.Blocks.advancedModem, new PartAdvancedModem() );
 
         // Subscribe to capability events
@@ -83,8 +85,11 @@ public class MCMPIntegration implements IMCMPAddon
     public static void attach( AttachCapabilitiesEvent<TileEntity> event )
     {
         TileEntity tile = event.getObject();
-        if( tile instanceof TileAdvancedModem || tile instanceof TileWirelessModem )
+        if( tile instanceof TileAdvancedModem || tile instanceof TileWirelessModem
+            || tile instanceof TilePeripheralBase || tile instanceof TileMonitor )
         {
+            // We need to attach to modems (obviously), but also any other tile created by BlockPeripheral. Otherwise
+            // IMultipart.convertToMultipartTile will error.
             event.addCapability( CAPABILITY_KEY, new BasicMultipart( tile ) );
         }
     }
@@ -94,7 +99,10 @@ public class MCMPIntegration implements IMCMPAddon
         private final TileEntity tile;
         private IMultipartTile wrapped;
 
-        private BasicMultipart( TileEntity tile ) {this.tile = tile;}
+        private BasicMultipart( TileEntity tile )
+        {
+            this.tile = tile;
+        }
 
         @Override
         public boolean hasCapability( @Nonnull Capability<?> capability, @Nullable EnumFacing facing )

src/main/java/dan200/computercraft/shared/integration/mcmp/PartPeripheral.java

@@ -10,6 +10,7 @@ import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.shared.peripheral.common.BlockPeripheral;
 import dan200.computercraft.shared.peripheral.common.BlockPeripheralVariant;
 import mcmultipart.api.multipart.IMultipart;
+import mcmultipart.api.slot.EnumCenterSlot;
 import mcmultipart.api.slot.EnumFaceSlot;
 import mcmultipart.api.slot.IPartSlot;
 import net.minecraft.block.Block;
@@ -20,34 +21,41 @@ import net.minecraft.util.math.BlockPos;
 import net.minecraft.world.IBlockAccess;
 import net.minecraft.world.World;
 
-public class PartNormalModem implements IMultipart
+import javax.annotation.Nonnull;
+
+public class PartPeripheral implements IMultipart
 {
     @Override
     public IPartSlot getSlotForPlacement( World world, BlockPos pos, IBlockState state, EnumFacing facing, float hitX, float hitY, float hitZ, EntityLivingBase placer )
     {
-        return EnumFaceSlot.fromFace( getFacing( state ) );
+        return getSlot( state );
     }
 
     @Override
     public IPartSlot getSlotFromWorld( IBlockAccess world, BlockPos pos, IBlockState state )
     {
-        return EnumFaceSlot.fromFace( getFacing( state ) );
+        return getSlot( state );
     }
 
-    private EnumFacing getFacing( IBlockState state )
+    @Nonnull
+    private static IPartSlot getSlot( IBlockState state )
     {
         BlockPeripheralVariant type = state.getValue( BlockPeripheral.VARIANT );
         if( type == BlockPeripheralVariant.WirelessModemUpOn || type == BlockPeripheralVariant.WirelessModemUpOff )
         {
-            return EnumFacing.UP;
+            return EnumFaceSlot.UP;
         }
         else if( type == BlockPeripheralVariant.WirelessModemDownOn || type == BlockPeripheralVariant.WirelessModemDownOff )
         {
-            return EnumFacing.UP;
+            return EnumFaceSlot.DOWN;
+        }
+        else if( type == BlockPeripheralVariant.WirelessModemOff || type == BlockPeripheralVariant.WirelessModemOn )
+        {
+            return EnumFaceSlot.fromFace( state.getValue( BlockPeripheral.FACING ) );
         }
         else
         {
-            return state.getValue( BlockPeripheral.FACING );
+            return EnumCenterSlot.CENTER;
         }
     }
 

src/main/java/dan200/computercraft/shared/peripheral/commandblock/CommandBlockPeripheral.java

@@ -52,7 +52,7 @@ public class CommandBlockPeripheral implements IPeripheral
         {
             case 0: // getCommand
                 return context.executeMainThreadTask( () -> new Object[] {
-                    m_commandBlock.getCommandBlockLogic().getCommand()
+                    m_commandBlock.getCommandBlockLogic().getCommand(),
                 } );
             case 1:
             {

src/main/java/dan200/computercraft/shared/peripheral/diskdrive/DiskDrivePeripheral.java

@@ -50,7 +50,7 @@ public class DiskDrivePeripheral implements IPeripheral
             "playAudio",
             "stopAudio",
             "ejectDisk",
-            "getDiskID"
+            "getDiskID",
         };
     }
 

src/main/java/dan200/computercraft/shared/peripheral/diskdrive/TileDiskDrive.java

@@ -62,7 +62,7 @@ public final class TileDiskDrive extends TileGeneric implements DefaultInventory
 
     @Nonnull
     private ItemStack m_diskStack = ItemStack.EMPTY;
-    private final LazyOptional<IItemHandlerModifiable> m_itemCap = LazyOptional.of( () -> new InvWrapper( this ) );
+    private LazyOptional<IItemHandlerModifiable> itemHandlerCap;
     private IMount m_diskMount = null;
 
     private boolean m_recordQueued = false;
@@ -82,6 +82,17 @@ public final class TileDiskDrive extends TileGeneric implements DefaultInventory
         if( m_recordPlaying ) stopRecord();
     }
 
+    @Override
+    protected void invalidateCaps()
+    {
+        super.invalidateCaps();
+        if( itemHandlerCap != null )
+        {
+            itemHandlerCap.invalidate();
+            itemHandlerCap = null;
+        }
+    }
+
     @Override
     public boolean onActivate( EntityPlayer player, EnumHand hand, EnumFacing side, float hitX, float hitY, float hitZ )
     {
@@ -540,7 +551,11 @@ public final class TileDiskDrive extends TileGeneric implements DefaultInventory
     @Override
     public <T> LazyOptional<T> getCapability( @Nonnull Capability<T> cap, @Nullable final EnumFacing side )
     {
-        if( cap == ITEM_HANDLER_CAPABILITY ) return m_itemCap.cast();
+        if( cap == ITEM_HANDLER_CAPABILITY )
+        {
+            if( itemHandlerCap == null ) itemHandlerCap = LazyOptional.of( () -> new InvWrapper( this ) );
+            return itemHandlerCap.cast();
+        }
         return super.getCapability( cap, side );
     }
 

src/main/java/dan200/computercraft/shared/peripheral/modem/ModemPeripheral.java

@@ -73,7 +73,7 @@ public abstract class ModemPeripheral implements IPeripheral, IPacketSender, IPa
             for( IComputerAccess computer : m_computers )
             {
                 computer.queueEvent( "modem_message", new Object[] {
-                    computer.getAttachmentName(), packet.getChannel(), packet.getReplyChannel(), packet.getPayload(), distance
+                    computer.getAttachmentName(), packet.getChannel(), packet.getReplyChannel(), packet.getPayload(), distance,
                 } );
             }
         }
@@ -89,7 +89,7 @@ public abstract class ModemPeripheral implements IPeripheral, IPacketSender, IPa
             for( IComputerAccess computer : m_computers )
             {
                 computer.queueEvent( "modem_message", new Object[] {
-                    computer.getAttachmentName(), packet.getChannel(), packet.getReplyChannel(), packet.getPayload()
+                    computer.getAttachmentName(), packet.getChannel(), packet.getReplyChannel(), packet.getPayload(),
                 } );
             }
         }

src/main/java/dan200/computercraft/shared/peripheral/modem/wired/BlockCable.java

@@ -86,7 +86,7 @@ public class BlockCable extends BlockGeneric implements WaterloggableBlock
     {
         if( !state.get( CABLE ) ) return false;
         if( state.get( MODEM ).getFacing() == direction ) return true;
-        return ComputerCraftAPI.getWiredElementAt( world, pos.offset( direction ), direction.getOpposite() ) != null;
+        return ComputerCraftAPI.getWiredElementAt( world, pos.offset( direction ), direction.getOpposite() ).isPresent();
     }
 
     @Nonnull
@@ -113,8 +113,7 @@ public class BlockCable extends BlockGeneric implements WaterloggableBlock
                     ItemStack item;
                     IBlockState newState;
 
-                    VoxelShape bb = CableShapes.getModemShape( state );
-                    if( WorldUtil.isVecInside( bb, hit.hitVec.subtract( pos.getX(), pos.getY(), pos.getZ() ) ) )
+                    if( WorldUtil.isVecInside( CableShapes.getModemShape( state ), hit.hitVec.subtract( pos.getX(), pos.getY(), pos.getZ() ) ) )
                     {
                         newState = state.with( MODEM, CableModemVariant.None );
                         item = new ItemStack( ComputerCraft.Items.wiredModem );
@@ -161,9 +160,7 @@ public class BlockCable extends BlockGeneric implements WaterloggableBlock
         if( modem == null ) return new ItemStack( ComputerCraft.Items.cable );
 
         // We've a modem and cable, so try to work out which one we're interacting with
-        TileEntity tile = world.getTileEntity( pos );
-        return tile instanceof TileCable && hit != null &&
-            CableShapes.getModemShape( state ).getBoundingBox().contains( hit.hitVec.subtract( pos.getX(), pos.getY(), pos.getZ() ) )
+        return hit != null && WorldUtil.isVecInside( CableShapes.getModemShape( state ), hit.hitVec.subtract( pos.getX(), pos.getY(), pos.getZ() ) )
             ? new ItemStack( ComputerCraft.Items.wiredModem )
             : new ItemStack( ComputerCraft.Items.cable );
 
@@ -202,21 +199,6 @@ public class BlockCable extends BlockGeneric implements WaterloggableBlock
             return getFluidState( state ).getBlockState();
         }
 
-        if( side == state.get( MODEM ).getFacing() && !state.isValidPosition( world, pos ) )
-        {
-            if( !state.get( CABLE ) ) return getFluidState( state ).getBlockState();
-
-            /* TODO:
-            TileEntity entity = world.getTileEntity( pos );
-            if( entity instanceof TileCable )
-            {
-                entity.modemChanged();
-                entity.connectionsChanged();
-            }
-            */
-            state = state.with( MODEM, CableModemVariant.None );
-        }
-
         return state.with( CONNECTIONS.get( side ), doesConnectVisually( state, world, pos, side ) );
     }
 

src/main/java/dan200/computercraft/shared/peripheral/modem/wired/TileCable.java

@@ -35,6 +35,7 @@ import net.minecraft.util.text.TextComponentTranslation;
 import net.minecraft.world.World;
 import net.minecraftforge.common.capabilities.Capability;
 import net.minecraftforge.common.util.LazyOptional;
+import net.minecraftforge.common.util.NonNullConsumer;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -90,7 +91,7 @@ public class TileCable extends TileGeneric implements IPeripheralTile
     private boolean m_connectionsFormed = false;
 
     private final WiredModemElement m_cable = new CableElement();
-    private LazyOptional<IWiredElement> m_cableCapability = LazyOptional.of( () -> m_cable );
+    private LazyOptional<IWiredElement> elementCap;
     private final IWiredNode m_node = m_cable.getNode();
     private final WiredModemPeripheral m_modem = new WiredModemPeripheral(
         new ModemState( () -> TickScheduler.schedule( this ) ),
@@ -113,6 +114,8 @@ public class TileCable extends TileGeneric implements IPeripheralTile
         }
     };
 
+    private final NonNullConsumer<LazyOptional<IWiredElement>> connectedNodeChanged = x -> connectionsChanged();
+
     public TileCable()
     {
         super( FACTORY );
@@ -152,6 +155,17 @@ public class TileCable extends TileGeneric implements IPeripheralTile
         onRemove();
     }
 
+    @Override
+    protected void invalidateCaps()
+    {
+        super.invalidateCaps();
+        if( elementCap != null )
+        {
+            elementCap.invalidate();
+            elementCap = null;
+        }
+    }
+
     @Override
     public void onLoad()
     {
@@ -322,18 +336,20 @@ public class TileCable extends TileGeneric implements IPeripheralTile
             BlockPos offset = current.offset( facing );
             if( !world.isBlockLoaded( offset ) ) continue;
 
-            IWiredElement element = ComputerCraftAPI.getWiredElementAt( world, offset, facing.getOpposite() );
-            if( element == null ) continue;
+            LazyOptional<IWiredElement> element = ComputerCraftAPI.getWiredElementAt( world, offset, facing.getOpposite() );
+            if( !element.isPresent() ) continue;
 
+            element.addListener( connectedNodeChanged );
+            IWiredNode node = element.orElseThrow( NullPointerException::new ).getNode();
             if( BlockCable.canConnectIn( state, facing ) )
             {
                 // If we can connect to it then do so
-                m_node.connectTo( element.getNode() );
+                m_node.connectTo( node );
             }
-            else if( m_node.getNetwork() == element.getNode().getNetwork() )
+            else if( m_node.getNetwork() == node.getNetwork() )
             {
                 // Otherwise if we're on the same network then attempt to void it.
-                m_node.disconnectFrom( element.getNode() );
+                m_node.disconnectFrom( node );
             }
         }
     }
@@ -341,9 +357,11 @@ public class TileCable extends TileGeneric implements IPeripheralTile
     void modemChanged()
     {
         // Tell anyone who cares that the connection state has changed
-        // TODO: Be more restrictive about this.
-        m_cableCapability.invalidate();
-        m_cableCapability = LazyOptional.of( () -> m_cable );
+        if( elementCap != null )
+        {
+            elementCap.invalidate();
+            elementCap = null;
+        }
 
         if( getWorld().isRemote ) return;
 
@@ -405,8 +423,9 @@ public class TileCable extends TileGeneric implements IPeripheralTile
     {
         if( capability == CapabilityWiredElement.CAPABILITY )
         {
-            return !m_destroyed && BlockCable.canConnectIn( getBlockState(), facing )
-                ? m_cableCapability.cast() : LazyOptional.empty();
+            if( m_destroyed || !BlockCable.canConnectIn( getBlockState(), facing ) ) return LazyOptional.empty();
+            if( elementCap == null ) elementCap = LazyOptional.of( () -> m_cable );
+            return elementCap.cast();
         }
 
         return super.getCapability( capability, facing );
@@ -418,7 +437,7 @@ public class TileCable extends TileGeneric implements IPeripheralTile
         return !m_destroyed && hasModem() && side == getDirection() ? m_modem : null;
     }
 
-    public boolean hasCable()
+    boolean hasCable()
     {
         return getBlockState().get( BlockCable.CABLE );
     }
@@ -428,7 +447,7 @@ public class TileCable extends TileGeneric implements IPeripheralTile
         return getBlockState().get( BlockCable.MODEM ) != CableModemVariant.None;
     }
 
-    boolean canAttachPeripheral()
+    private boolean canAttachPeripheral()
     {
         return hasCable() && hasModem();
     }

src/main/java/dan200/computercraft/shared/peripheral/modem/wired/TileWiredModemFull.java

@@ -8,7 +8,7 @@ package dan200.computercraft.shared.peripheral.modem.wired;
 
 import com.google.common.base.Objects;
 import dan200.computercraft.ComputerCraft;
-import dan200.computercraft.ComputerCraftAPIImpl;
+import dan200.computercraft.api.ComputerCraftAPI;
 import dan200.computercraft.api.network.wired.IWiredElement;
 import dan200.computercraft.api.network.wired.IWiredNode;
 import dan200.computercraft.api.peripheral.IPeripheral;
@@ -33,6 +33,7 @@ import net.minecraft.util.text.TextComponentTranslation;
 import net.minecraft.world.World;
 import net.minecraftforge.common.capabilities.Capability;
 import net.minecraftforge.common.util.LazyOptional;
+import net.minecraftforge.common.util.NonNullConsumer;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -105,10 +106,10 @@ public class TileWiredModemFull extends TileGeneric implements IPeripheralTile
 
     private final ModemState m_modemState = new ModemState( () -> TickScheduler.schedule( this ) );
     private final WiredModemElement m_element = new FullElement( this );
-    private final LazyOptional<WiredModemElement> m_elementCap = LazyOptional.of( () -> m_element );
+    private LazyOptional<IWiredElement> elementCap;
     private final IWiredNode m_node = m_element.getNode();
 
-    private int m_state = 0;
+    private final NonNullConsumer<LazyOptional<IWiredElement>> connectedNodeChanged = x -> connectionsChanged();
 
     public TileWiredModemFull()
     {
@@ -143,6 +144,17 @@ public class TileWiredModemFull extends TileGeneric implements IPeripheralTile
         doRemove();
     }
 
+    @Override
+    protected void invalidateCaps()
+    {
+        super.invalidateCaps();
+        if( elementCap != null )
+        {
+            elementCap.invalidate();
+            elementCap = null;
+        }
+    }
+
     @Override
     public void remove()
     {
@@ -275,11 +287,11 @@ public class TileWiredModemFull extends TileGeneric implements IPeripheralTile
             BlockPos offset = current.offset( facing );
             if( !world.isBlockLoaded( offset ) ) continue;
 
-            IWiredElement element = ComputerCraftAPIImpl.INSTANCE.getWiredElementAt( world, offset, facing.getOpposite() );
-            if( element == null ) continue;
+            LazyOptional<IWiredElement> element = ComputerCraftAPI.getWiredElementAt( world, offset, facing.getOpposite() );
+            if( !element.isPresent() ) continue;
 
-            // If we can connect to it then do so
-            m_node.connectTo( element.getNode() );
+            element.addListener( connectedNodeChanged );
+            m_node.connectTo( element.orElseThrow( NullPointerException::new ).getNode() );
         }
     }
 
@@ -350,7 +362,11 @@ public class TileWiredModemFull extends TileGeneric implements IPeripheralTile
     @Override
     public <T> LazyOptional<T> getCapability( @Nonnull Capability<T> capability, @Nullable EnumFacing facing )
     {
-        if( capability == CapabilityWiredElement.CAPABILITY ) return m_elementCap.cast();
+        if( capability == CapabilityWiredElement.CAPABILITY )
+        {
+            if( elementCap == null ) elementCap = LazyOptional.of( () -> m_element );
+            return elementCap.cast();
+        }
         return super.getCapability( capability, facing );
     }
 

src/main/java/dan200/computercraft/shared/peripheral/modem/wired/WiredModemPeripheral.java

@@ -277,7 +277,7 @@ public abstract class WiredModemPeripheral extends ModemPeripheral implements IW
         private final String[] m_methods;
         private final Map<String, Integer> m_methodMap;
 
-        public RemotePeripheralWrapper( WiredModemElement element, IPeripheral peripheral, IComputerAccess computer, String name )
+        RemotePeripheralWrapper( WiredModemElement element, IPeripheral peripheral, IComputerAccess computer, String name )
         {
             m_element = element;
             m_peripheral = peripheral;

src/main/java/dan200/computercraft/shared/peripheral/modem/wireless/TileWirelessModem.java

@@ -8,6 +8,7 @@ package dan200.computercraft.shared.peripheral.modem.wireless;
 
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.api.peripheral.IPeripheral;
+import dan200.computercraft.api.peripheral.IPeripheralTile;
 import dan200.computercraft.shared.common.TileGeneric;
 import dan200.computercraft.shared.peripheral.modem.ModemPeripheral;
 import dan200.computercraft.shared.peripheral.modem.ModemState;
@@ -22,8 +23,9 @@ import net.minecraft.util.math.Vec3d;
 import net.minecraft.world.World;
 
 import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
 
-public class TileWirelessModem extends TileGeneric
+public class TileWirelessModem extends TileGeneric implements IPeripheralTile
 {
     public static final NamedBlockEntityType<TileWirelessModem> FACTORY_NORMAL = NamedBlockEntityType.create(
         new ResourceLocation( ComputerCraft.MOD_ID, "wireless_modem_normal" ),
@@ -146,4 +148,13 @@ public class TileWirelessModem extends TileGeneric
             getWorld().setBlockState( getPos(), state.with( BlockWirelessModem.ON, on ) );
         }
     }
+
+
+    @Nullable
+    @Override
+    public IPeripheral getPeripheral( @Nonnull EnumFacing side )
+    {
+        updateDirection();
+        return side == modemDirection ? modem : null;
+    }
 }

src/main/java/dan200/computercraft/shared/peripheral/monitor/TileMonitor.java

@@ -155,7 +155,7 @@ public class TileMonitor extends TileGeneric implements IPeripheralTile
                     for( IComputerAccess computer : monitor.m_computers )
                     {
                         computer.queueEvent( "monitor_resize", new Object[] {
-                            computer.getAttachmentName()
+                            computer.getAttachmentName(),
                         } );
                     }
                 }
@@ -321,7 +321,7 @@ public class TileMonitor extends TileGeneric implements IPeripheralTile
         return getDirection().rotateYCCW();
     }
 
-    private EnumFacing getDown()
+    public EnumFacing getDown()
     {
         EnumFacing orientation = getOrientation();
         if( orientation == EnumFacing.NORTH ) return EnumFacing.UP;
@@ -625,7 +625,7 @@ public class TileMonitor extends TileGeneric implements IPeripheralTile
                 for( IComputerAccess computer : monitor.m_computers )
                 {
                     computer.queueEvent( "monitor_touch", new Object[] {
-                        computer.getAttachmentName(), xCharPos, yCharPos
+                        computer.getAttachmentName(), xCharPos, yCharPos,
                     } );
                 }
             }

src/main/java/dan200/computercraft/shared/peripheral/printer/TilePrinter.java

@@ -61,8 +61,7 @@ public final class TilePrinter extends TileGeneric implements DefaultSidedInvent
     ITextComponent customName;
 
     private final NonNullList<ItemStack> m_inventory = NonNullList.withSize( 13, ItemStack.EMPTY );
-    private IItemHandlerModifiable m_itemHandlerAll = new InvWrapper( this );
-    private LazyOptional<IItemHandlerModifiable>[] m_itemHandlerSides;
+    private LazyOptional<IItemHandlerModifiable>[] itemHandlerCaps;
 
     private final Terminal m_page = new Terminal( ItemPrintout.LINE_MAX_LENGTH, ItemPrintout.LINES_PER_PAGE );
     private String m_pageTitle = "";
@@ -79,6 +78,22 @@ public final class TilePrinter extends TileGeneric implements DefaultSidedInvent
         ejectContents();
     }
 
+    @Override
+    protected void invalidateCaps()
+    {
+        super.invalidateCaps();
+
+        if( itemHandlerCaps != null )
+        {
+            for( int i = 0; i < itemHandlerCaps.length; i++ )
+            {
+                if( itemHandlerCaps[i] == null ) continue;
+                itemHandlerCaps[i].invalidate();
+                itemHandlerCaps[i] = null;
+            }
+        }
+    }
+
     @Override
     public boolean onActivate( EntityPlayer player, EnumHand hand, EnumFacing side, float hitX, float hitY, float hitZ )
     {
@@ -516,7 +531,6 @@ public final class TilePrinter extends TileGeneric implements DefaultSidedInvent
         getWorld().setBlockState( getPos(), state.with( BlockPrinter.TOP, top ).with( BlockPrinter.BOTTOM, bottom ) );
     }
 
-
     @SuppressWarnings( { "unchecked", "rawtypes" } )
     @Nonnull
     @Override
@@ -524,28 +538,16 @@ public final class TilePrinter extends TileGeneric implements DefaultSidedInvent
     {
         if( capability == ITEM_HANDLER_CAPABILITY )
         {
-            LazyOptional<IItemHandlerModifiable>[] handlers = m_itemHandlerSides;
-            if( handlers == null ) handlers = m_itemHandlerSides = new LazyOptional[6];
+            LazyOptional<IItemHandlerModifiable>[] handlers = itemHandlerCaps;
+            if( handlers == null ) handlers = itemHandlerCaps = new LazyOptional[7];
 
-            LazyOptional<IItemHandlerModifiable> handler;
-            if( facing == null )
+            int index = facing == null ? 0 : 1 + facing.getIndex();
+            LazyOptional<IItemHandlerModifiable> handler = handlers[index];
+            if( handler == null )
             {
-                int i = 6;
-                handler = handlers[i];
-                if( handler == null )
-                {
-                    handler = handlers[i] = LazyOptional.of( () -> m_itemHandlerAll );
-                }
-            }
-            else
-            {
-
-                int i = facing.ordinal();
-                handler = handlers[i];
-                if( handler == null )
-                {
-                    handler = handlers[i] = LazyOptional.of( () -> new SidedInvWrapper( this, facing ) );
-                }
+                handler = handlers[index] = facing == null
+                    ? LazyOptional.of( () -> new InvWrapper( this ) )
+                    : LazyOptional.of( () -> new SidedInvWrapper( this, facing ) );
             }
 
             return handler.cast();

src/main/java/dan200/computercraft/shared/peripheral/speaker/SpeakerPeripheral.java

@@ -59,8 +59,8 @@ public abstract class SpeakerPeripheral implements IPeripheral
     public String[] getMethodNames()
     {
         return new String[] {
-            "playSound", // Plays sound at resourceLocator
-            "playNote" // Plays note
+            "playSound",
+            "playNote",
         };
     }
 

src/main/java/dan200/computercraft/shared/pocket/apis/PocketAPI.java

@@ -35,9 +35,7 @@ public class PocketAPI implements ILuaAPI
     @Override
     public String[] getNames()
     {
-        return new String[] {
-            "pocket"
-        };
+        return new String[] { "pocket" };
     }
 
     @Nonnull
@@ -46,7 +44,7 @@ public class PocketAPI implements ILuaAPI
     {
         return new String[] {
             "equipBack",
-            "unequipBack"
+            "unequipBack",
         };
     }
 

src/main/java/dan200/computercraft/shared/pocket/core/PocketServerComputer.java

@@ -10,6 +10,7 @@ import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.api.pocket.IPocketAccess;
 import dan200.computercraft.api.pocket.IPocketUpgrade;
+import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.shared.common.IColouredItem;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
 import dan200.computercraft.shared.computer.core.ServerComputer;
@@ -123,14 +124,14 @@ public class PocketServerComputer extends ServerComputer implements IPocketAcces
     public void invalidatePeripheral()
     {
         IPeripheral peripheral = m_upgrade == null ? null : m_upgrade.createPeripheral( this );
-        setPeripheral( 2, peripheral );
+        setPeripheral( ComputerSide.BACK, peripheral );
     }
 
     @Nonnull
     @Override
     public Map<ResourceLocation, IPeripheral> getUpgrades()
     {
-        return m_upgrade == null ? Collections.emptyMap() : Collections.singletonMap( m_upgrade.getUpgradeID(), getPeripheral( 2 ) );
+        return m_upgrade == null ? Collections.emptyMap() : Collections.singletonMap( m_upgrade.getUpgradeID(), getPeripheral( ComputerSide.BACK ) );
     }
 
     public IPocketUpgrade getUpgrade()

src/main/java/dan200/computercraft/shared/pocket/items/ItemPocketComputer.java

@@ -12,6 +12,7 @@ import dan200.computercraft.api.ComputerCraftAPI;
 import dan200.computercraft.api.filesystem.IMount;
 import dan200.computercraft.api.media.IMedia;
 import dan200.computercraft.api.pocket.IPocketUpgrade;
+import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.shared.PocketUpgrades;
 import dan200.computercraft.shared.common.IColouredItem;
 import dan200.computercraft.shared.computer.core.ClientComputer;
@@ -120,7 +121,7 @@ public class ItemPocketComputer extends Item implements IComputerItem, IMedia, I
                 // Update pocket upgrade
                 if( upgrade != null )
                 {
-                    upgrade.update( computer, computer.getPeripheral( 2 ) );
+                    upgrade.update( computer, computer.getPeripheral( ComputerSide.BACK ) );
                 }
             }
         }
@@ -149,7 +150,7 @@ public class ItemPocketComputer extends Item implements IComputerItem, IMedia, I
                 if( upgrade != null )
                 {
                     computer.updateValues( player, stack, upgrade );
-                    stop = upgrade.onRightClick( world, computer, computer.getPeripheral( 2 ) );
+                    stop = upgrade.onRightClick( world, computer, computer.getPeripheral( ComputerSide.BACK ) );
                 }
             }