Add an API for wired networks

The API is composed of three primary classes:

- IWiredElement: Represents some physical entity in the network. This
   will generally be a block (such as a cable or modem), but it is not
   required to be.

   Each element can provide a series of peripherals, which will be
   exposed to other elements on the network.

- IWiredNode: Every wired element has a unique wired node. This acts
   as a thread-safe proxy for communicating with the rest of the
   network (such as sending packets). Each node is also its own packet
   network.

- IWiredNetwork: This is responsible for keeping track of nodes and
   peripherals in the network. It provides methods for forming and
   breaking connections, correctly joining and splitting networks where
   needed.

Tiles which wish to be part of a wired network should implement
IWiredElementTile or register a custom IWiredProvider. When loaded into
the world, it should connect to adjacent nodes. Similarly, when removed
(either due to being broken or chunk unloads), it should break those
connections.

There is no method to query the layout of the network, as that offers
greater flexibility in changing or extending the implementation later
on.

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

@@ -12,6 +12,9 @@ import dan200.computercraft.api.lua.ILuaAPIFactory;
 import dan200.computercraft.api.media.IMedia;
 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.network.wired.IWiredProvider;
 import dan200.computercraft.api.peripheral.IComputerAccess;
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.api.peripheral.IPeripheralProvider;
@@ -21,6 +24,7 @@ import dan200.computercraft.api.redstone.IBundledRedstoneProvider;
 import dan200.computercraft.api.turtle.ITurtleUpgrade;
 import net.minecraft.util.EnumFacing;
 import net.minecraft.util.math.BlockPos;
+import net.minecraft.world.IBlockAccess;
 import net.minecraft.world.World;
 
 import javax.annotation.Nonnull;
@@ -328,6 +332,81 @@ public final class ComputerCraftAPI
         }
     }
 
+    /**
+     * Registers a peripheral handler to convert blocks into {@link IPeripheral} implementations.
+     *
+     * @param handler The peripheral provider to register.
+     * @see dan200.computercraft.api.peripheral.IPeripheral
+     * @see dan200.computercraft.api.peripheral.IPeripheralProvider
+     */
+    public static void registerWiredProvider( @Nonnull IWiredProvider handler )
+    {
+        findCC();
+        if ( computerCraft_registerWiredProvider != null)
+        {
+            try {
+                computerCraft_registerWiredProvider.invoke( null, handler );
+            } catch (Exception e){
+                // It failed
+            }
+        }
+    }
+
+    /**
+     * Construct a new wired node for a given wired element
+     *
+     * @param element The element to construct it for
+     * @return The element's node
+     * @see IWiredElement#getNode()
+     */
+    @Nonnull
+    public static IWiredNode createWiredNodeForElement( @Nonnull IWiredElement element )
+    {
+        findCC();
+        if( computerCraft_createWiredNodeForElement != null )
+        {
+            try
+            {
+                return (IWiredNode) computerCraft_createWiredNodeForElement.invoke( null, element );
+            }
+            catch( ReflectiveOperationException e )
+            {
+                throw new IllegalStateException( "Error creating wired node", e );
+            }
+        }
+        else
+        {
+            throw new IllegalStateException( "ComputerCraft cannot be found" );
+        }
+    }
+
+    /**
+     * Get the wired network element for a block in world
+     *
+     * @param world The world the block exists in
+     * @param pos   The position the block exists in
+     * @param side  The side to extract the network element from
+     * @return The element's node
+     * @see IWiredElement#getNode()
+     */
+    @Nullable
+    public static IWiredElement getWiredElementAt( @Nonnull IBlockAccess world, @Nonnull BlockPos pos, @Nonnull EnumFacing side )
+    {
+        findCC();
+        if( computerCraft_getWiredElementAt != null )
+        {
+            try
+            {
+                return (IWiredElement) computerCraft_getWiredElementAt.invoke( null, world, pos, side );
+            }
+            catch( ReflectiveOperationException ignored )
+            {
+            }
+        }
+        
+        return null;
+    }
+
     // The functions below here are private, and are used to interface with the non-API ComputerCraft classes.
     // Reflection is used here so you can develop your mod without decompiling ComputerCraft and including
     // it in your solution, and so your mod won't crash if ComputerCraft is installed.
@@ -374,6 +453,15 @@ public final class ComputerCraftAPI
                 computerCraft_registerAPIFactory = findCCMethod( "registerAPIFactory", new Class<?>[] {
                     ILuaAPIFactory.class
                 } );
+                computerCraft_registerWiredProvider = findCCMethod( "registerWiredProvider", new Class<?>[] {
+                    IWiredProvider.class
+                } );
+                computerCraft_createWiredNodeForElement = findCCMethod( "createWiredNodeForElement", new Class<?>[] {
+                    IWiredElement.class
+                } );
+                computerCraft_getWiredElementAt = findCCMethod( "getWiredElementAt", new Class<?>[]{
+                    IBlockAccess.class, BlockPos.class, EnumFacing.class
+                } );
             } catch( Exception e ) {
                 System.out.println( "ComputerCraftAPI: ComputerCraft not found." );
             } finally {
@@ -411,4 +499,7 @@ public final class ComputerCraftAPI
     private static Method computerCraft_registerPocketUpgrade = null;
     private static Method computerCraft_getWirelessNetwork = null;
     private static Method computerCraft_registerAPIFactory = null;
+    private static Method computerCraft_registerWiredProvider = null;
+    private static Method computerCraft_createWiredNodeForElement = null;
+    private static Method computerCraft_getWiredElementAt = null;
 }