Load the CC API with services loaders

This is a little odd (it's more complex for one!), but means we can
reuse the internal API interface in other classes, which is useful for
the data provider refactor I'm about to do.

This is much nicer in Java 17 :D (records, ServiceLoader.stream()),
but such is the perils of still targetting 1.16.

build.gradle

@@ -15,6 +15,7 @@ plugins {
 }
 
 
+import cc.tweaked.gradle.ExtensionsKt
 import cc.tweaked.gradle.IlluaminateExec
 import cc.tweaked.gradle.IlluaminateExecToDir
 import org.apache.tools.ant.taskdefs.condition.Os
@@ -136,6 +137,9 @@ dependencies {
     minecraft "net.minecraftforge:forge:${mc_version}-${forge_version}"
     annotationProcessor 'org.spongepowered:mixin:0.8.4:processor'
 
+    compileOnly(libs.jetbrainsAnnotations)
+    ExtensionsKt.annotationProcessorEverywhere(dependencies, libs.autoService)
+
     extraModsCompileOnly fg.deobf("mezz.jei:jei-1.16.5:7.7.0.104:api")
     extraModsRuntimeOnly fg.deobf("mezz.jei:jei-1.16.5:7.7.0.104")
 
@@ -144,9 +148,6 @@ dependencies {
 
     shade 'org.squiddev:Cobalt:0.5.7'
 
-    testCompileOnly(libs.autoService)
-    testAnnotationProcessor(libs.autoService)
-
     testImplementation(libs.bundles.test)
     testImplementation(libs.bundles.kotlin)
     testRuntimeOnly(libs.bundles.testRuntime)
@@ -442,13 +443,7 @@ def testServer = tasks.register("testServer", JavaExec.class) {
 
     // Copy from runTestServer. We do it in this slightly odd way as runTestServer
     // isn't created until the task is configured (which is no good for us).
-    JavaExec exec = tasks.getByName("runTestServer")
-    dependsOn(exec.getDependsOn())
-    exec.copyTo(it)
-    setClasspath(exec.getClasspath())
-    mainClass = exec.mainClass
-    javaLauncher = exec.javaLauncher
-    setArgs(exec.getArgs())
+    ExtensionsKt.copyToFull(tasks.getByName("runTestServer"), it)
 
     // Jacoco and modlauncher don't play well together as the classes loaded in-game don't
     // match up with those written to disk. We get Jacoco to dump all classes to disk, and

buildSrc/src/main/kotlin/cc/tweaked/gradle/Extensions.kt

@@ -0,0 +1,20 @@
+package cc.tweaked.gradle
+
+import org.gradle.api.artifacts.dsl.DependencyHandler
+import org.gradle.api.tasks.JavaExec
+
+fun DependencyHandler.annotationProcessorEverywhere(dep: Any) {
+    add("compileOnly", dep)
+    add("annotationProcessor", dep)
+
+    add("testCompileOnly", dep)
+    add("testAnnotationProcessor", dep)
+}
+
+fun JavaExec.copyToFull(spec: JavaExec) {
+    copyTo(spec)
+    spec.classpath = classpath
+    spec.mainClass.set(mainClass)
+    spec.javaLauncher.set(javaLauncher)
+    spec.args = args
+}

gradle/libs.versions.toml

@@ -1,5 +1,6 @@
 [versions]
 autoService = "1.0.1"
+jetbrainsAnnotations = "23.0.0"
 kotlin = "1.7.10"
 kotlin-coroutines = "1.6.0"
 
@@ -10,6 +11,7 @@ junit = "5.9.1"
 
 [libraries]
 autoService = { module = "com.google.auto.service:auto-service", version.ref = "autoService" }
+jetbrainsAnnotations = { module = "org.jetbrains:annotations", version.ref = "jetbrainsAnnotations" }
 kotlin-coroutines = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-core", version.ref = "kotlin-coroutines" }
 kotlin-stdlib = { module = "org.jetbrains.kotlin:kotlin-stdlib-jdk8", version.ref = "kotlin" }
 

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

@@ -5,7 +5,7 @@
  */
 package dan200.computercraft;
 
-import dan200.computercraft.api.ComputerCraftAPI.IComputerCraftAPI;
+import com.google.auto.service.AutoService;
 import dan200.computercraft.api.detail.IDetailProvider;
 import dan200.computercraft.api.filesystem.IMount;
 import dan200.computercraft.api.filesystem.IWritableMount;
@@ -23,6 +23,7 @@ import dan200.computercraft.core.apis.ApiFactories;
 import dan200.computercraft.core.asm.GenericMethod;
 import dan200.computercraft.core.filesystem.FileMount;
 import dan200.computercraft.core.filesystem.ResourceMount;
+import dan200.computercraft.impl.ComputerCraftAPIService;
 import dan200.computercraft.shared.*;
 import dan200.computercraft.shared.computer.core.ServerContext;
 import dan200.computercraft.shared.peripheral.generic.GenericPeripheralProvider;
@@ -49,16 +50,11 @@ import java.io.InputStream;
 
 import static dan200.computercraft.shared.Capabilities.CAPABILITY_WIRED_ELEMENT;
 
-public final class ComputerCraftAPIImpl implements IComputerCraftAPI
+@AutoService( ComputerCraftAPIService.class )
+public final class ComputerCraftAPIImpl implements ComputerCraftAPIService
 {
-    public static final ComputerCraftAPIImpl INSTANCE = new ComputerCraftAPIImpl();
-
     private String version;
 
-    private ComputerCraftAPIImpl()
-    {
-    }
-
     public static InputStream getResourceFile( MinecraftServer server, String domain, String subPath )
     {
         IResourceManager manager = server.getDataPackRegistries().getResourceManager();

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

@@ -22,6 +22,7 @@ import dan200.computercraft.api.peripheral.IPeripheralProvider;
 import dan200.computercraft.api.pocket.IPocketUpgrade;
 import dan200.computercraft.api.redstone.IBundledRedstoneProvider;
 import dan200.computercraft.api.turtle.ITurtleUpgrade;
+import dan200.computercraft.impl.ComputerCraftAPIService;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.Direction;
 import net.minecraft.util.math.BlockPos;
@@ -267,64 +268,9 @@ public final class ComputerCraftAPI
         return getInstance().getWiredElementAt( world, pos, side );
     }
 
-    private static IComputerCraftAPI instance;
-
     @Nonnull
-    private static IComputerCraftAPI getInstance()
+    private static ComputerCraftAPIService getInstance()
     {
-        if( instance != null ) return instance;
-
-        try
-        {
-            return instance = (IComputerCraftAPI) Class.forName( "dan200.computercraft.ComputerCraftAPIImpl" )
-                .getField( "INSTANCE" ).get( null );
-        }
-        catch( ReflectiveOperationException e )
-        {
-            throw new IllegalStateException( "Cannot find ComputerCraft API", e );
-        }
-    }
-
-    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 );
-
-        void registerGenericSource( @Nonnull GenericSource source );
-
-        void registerGenericCapability( @Nonnull Capability<?> capability );
-
-        void registerTurtleUpgrade( @Nonnull ITurtleUpgrade upgrade );
-
-        void registerBundledRedstoneProvider( @Nonnull IBundledRedstoneProvider provider );
-
-        int getBundledRedstoneOutput( @Nonnull World world, @Nonnull BlockPos pos, @Nonnull Direction side );
-
-        void registerMediaProvider( @Nonnull IMediaProvider provider );
-
-        void registerPocketUpgrade( @Nonnull IPocketUpgrade upgrade );
-
-        @Nonnull
-        IPacketNetwork getWirelessNetwork();
-
-        void registerAPIFactory( @Nonnull ILuaAPIFactory factory );
-
-        <T> void registerDetailProvider( @Nonnull Class<T> type, @Nonnull IDetailProvider<T> provider );
-
-        @Nonnull
-        IWiredNode createWiredNodeForElement( @Nonnull IWiredElement element );
-
-        @Nonnull
-        LazyOptional<IWiredElement> getWiredElementAt( @Nonnull IBlockReader world, @Nonnull BlockPos pos, @Nonnull Direction side );
+        return ComputerCraftAPIService.get();
     }
 }

src/main/java/dan200/computercraft/impl/ComputerCraftAPIService.java

@@ -0,0 +1,103 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2022. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.impl;
+
+import dan200.computercraft.api.ComputerCraftAPI;
+import dan200.computercraft.api.detail.IDetailProvider;
+import dan200.computercraft.api.filesystem.IMount;
+import dan200.computercraft.api.filesystem.IWritableMount;
+import dan200.computercraft.api.lua.GenericSource;
+import dan200.computercraft.api.lua.ILuaAPIFactory;
+import dan200.computercraft.api.media.IMediaProvider;
+import dan200.computercraft.api.network.IPacketNetwork;
+import dan200.computercraft.api.network.wired.IWiredElement;
+import dan200.computercraft.api.network.wired.IWiredNode;
+import dan200.computercraft.api.peripheral.IPeripheralProvider;
+import dan200.computercraft.api.pocket.IPocketUpgrade;
+import dan200.computercraft.api.redstone.IBundledRedstoneProvider;
+import dan200.computercraft.api.turtle.ITurtleUpgrade;
+import net.minecraft.util.Direction;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.world.IBlockReader;
+import net.minecraft.world.World;
+import net.minecraftforge.common.capabilities.Capability;
+import net.minecraftforge.common.util.LazyOptional;
+import org.jetbrains.annotations.ApiStatus;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * Backing interface for {@link ComputerCraftAPI}
+ * <p>
+ * Do <strong>NOT</strong> directly reference this class. It exists for internal use by the API.
+ */
+@ApiStatus.Internal
+public interface ComputerCraftAPIService
+{
+    static ComputerCraftAPIService get()
+    {
+        ComputerCraftAPIService instance = Instance.INSTANCE;
+        return instance == null ? Services.raise( ComputerCraftAPIService.class, Instance.ERROR ) : instance;
+    }
+
+    @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 );
+
+    void registerGenericSource( @Nonnull GenericSource source );
+
+    void registerGenericCapability( @Nonnull Capability<?> capability );
+
+    void registerTurtleUpgrade( @Nonnull ITurtleUpgrade upgrade );
+
+    void registerBundledRedstoneProvider( @Nonnull IBundledRedstoneProvider provider );
+
+    int getBundledRedstoneOutput( @Nonnull World world, @Nonnull BlockPos pos, @Nonnull Direction side );
+
+    void registerMediaProvider( @Nonnull IMediaProvider provider );
+
+    void registerPocketUpgrade( @Nonnull IPocketUpgrade upgrade );
+
+    @Nonnull
+    IPacketNetwork getWirelessNetwork();
+
+    void registerAPIFactory( @Nonnull ILuaAPIFactory factory );
+
+    <T> void registerDetailProvider( @Nonnull Class<T> type, @Nonnull IDetailProvider<T> provider );
+
+    @Nonnull
+    IWiredNode createWiredNodeForElement( @Nonnull IWiredElement element );
+
+    @Nonnull
+    LazyOptional<IWiredElement> getWiredElementAt( @Nonnull IBlockReader world, @Nonnull BlockPos pos, @Nonnull Direction side );
+
+    class Instance
+    {
+        static final @Nullable ComputerCraftAPIService INSTANCE;
+        static final @Nullable Throwable ERROR;
+
+        static
+        {
+            Services.LoadedService<ComputerCraftAPIService> helper = Services.tryLoad( ComputerCraftAPIService.class );
+            INSTANCE = helper.instance();
+            ERROR = helper.error();
+        }
+
+        private Instance()
+        {
+        }
+    }
+}

src/main/java/dan200/computercraft/impl/ServiceException.java

@@ -0,0 +1,26 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2022. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.impl;
+
+import org.jetbrains.annotations.ApiStatus;
+
+import javax.annotation.Nullable;
+
+/**
+ * A ComputerCraft-related service failed to load.
+ * <p>
+ * Do <strong>NOT</strong> directly reference this class. It exists for internal use by the API.
+ */
+@ApiStatus.Internal
+class ServiceException extends RuntimeException
+{
+    private static final long serialVersionUID = -8392300691666423882L;
+
+    ServiceException( String message, @Nullable Throwable cause )
+    {
+        super( message, cause );
+    }
+}

src/main/java/dan200/computercraft/impl/Services.java

@@ -0,0 +1,111 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2022. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.impl;
+
+import org.jetbrains.annotations.ApiStatus;
+
+import javax.annotation.Nullable;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.ServiceLoader;
+import java.util.stream.Collectors;
+
+/**
+ * Utilities for loading services.
+ * <p>
+ * Do <strong>NOT</strong> directly reference this class. It exists for internal use by the API.
+ */
+@ApiStatus.Internal
+public final class Services
+{
+    private Services()
+    {
+    }
+
+    /**
+     * Load a service, asserting that only a single instance is registered.
+     *
+     * @param klass The class of the service to load.
+     * @param <T>   The class of the service to load.
+     * @return The constructed service instance.
+     * @throws IllegalStateException When the service cannot be loaded.
+     */
+    public static <T> T load( Class<T> klass )
+    {
+        List<T> services = new ArrayList<>( 1 );
+        for( T provider : ServiceLoader.load( klass ) ) services.add( provider );
+        switch( services.size() )
+        {
+            case 1:
+                return services.get( 0 );
+            case 0:
+                throw new IllegalStateException( "Cannot find service for " + klass.getName() );
+            default:
+                String serviceTypes = services.stream().map( x -> x.getClass().getName() ).collect( Collectors.joining( ", " ) );
+                throw new IllegalStateException( "Multiple services for " + klass.getName() + ": " + serviceTypes );
+        }
+    }
+
+    /**
+     * Attempt to load a service with {@link #load(Class)}.
+     *
+     * @param klass The class of the service to load.
+     * @param <T>   The class of the service to load.
+     * @return The result type, either containing the service or an exception.
+     * @see ComputerCraftAPIService Intended usage of this class.
+     */
+    public static <T> LoadedService<T> tryLoad( Class<T> klass )
+    {
+        try
+        {
+            return new LoadedService<>( load( klass ), null );
+        }
+        catch( Exception | LinkageError e )
+        {
+            return new LoadedService<>( null, e );
+        }
+    }
+
+    /**
+     * Raise an exception from trying to load a specific service.
+     *
+     * @param klass The class of the service we failed to load.
+     * @param e     The original exception caused by loading this class.
+     * @param <T>   The class of the service to load.
+     * @return Never
+     * @see #tryLoad(Class)
+     * @see LoadedService#error()
+     */
+    public static <T> T raise( Class<T> klass, @Nullable Throwable e )
+    {
+        // Throw a new exception so there's a useful stack trace there somewhere!
+        throw new ServiceException( "Failed to instantiate " + klass.getName(), e );
+    }
+
+    public static class LoadedService<T>
+    {
+        private final @Nullable T instance;
+        private final @Nullable Throwable error;
+
+        LoadedService( @Nullable T instance, @Nullable Throwable error )
+        {
+            this.instance = instance;
+            this.error = error;
+        }
+
+        @Nullable
+        public T instance()
+        {
+            return instance;
+        }
+
+        @Nullable
+        public Throwable error()
+        {
+            return error;
+        }
+    }
+}

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

@@ -5,11 +5,11 @@
  */
 package dan200.computercraft.shared.peripheral.modem.wired;
 
+import dan200.computercraft.api.ComputerCraftAPI;
 import dan200.computercraft.api.network.wired.IWiredElement;
 import dan200.computercraft.api.network.wired.IWiredNetworkChange;
 import dan200.computercraft.api.network.wired.IWiredNode;
 import dan200.computercraft.api.peripheral.IPeripheral;
-import dan200.computercraft.shared.wired.WiredNode;
 
 import javax.annotation.Nonnull;
 import java.util.HashMap;
@@ -17,7 +17,7 @@ import java.util.Map;
 
 public abstract class WiredModemElement implements IWiredElement
 {
-    private final IWiredNode node = new WiredNode( this );
+    private final IWiredNode node = ComputerCraftAPI.createWiredNodeForElement( this );
     private final Map<String, IPeripheral> remotePeripherals = new HashMap<>();
 
     @Nonnull

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

@@ -6,6 +6,7 @@
 package dan200.computercraft.shared.peripheral.modem.wireless;
 
 import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.api.ComputerCraftAPI;
 import dan200.computercraft.api.network.IPacketNetwork;
 import dan200.computercraft.shared.peripheral.modem.ModemPeripheral;
 import dan200.computercraft.shared.peripheral.modem.ModemState;
@@ -61,6 +62,6 @@ public abstract class WirelessModemPeripheral extends ModemPeripheral
     @Override
     protected IPacketNetwork getNetwork()
     {
-        return WirelessNetwork.getUniversal();
+        return ComputerCraftAPI.getWirelessNetwork();
     }
 }

src/test/java/dan200/computercraft/shared/network/server/UploadFileMessageTest.java

@@ -35,7 +35,7 @@ public class UploadFileMessageTest
      *
      * @param sentFiles The files to send.
      */
-    @Property( tries = 500 )
+    @Property( tries = 200 )
     @Tag( "slow" )
     public void testRoundTrip( @ForAll( "fileUploads" ) List<FileUpload> sentFiles )
     {