Update the executor to work with the new calling system

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

@@ -0,0 +1,87 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2018. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+
+package dan200.computercraft.core.lua;
+
+import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.api.lua.ICallContext;
+import dan200.computercraft.api.lua.ILuaTask;
+import dan200.computercraft.api.lua.LuaException;
+import dan200.computercraft.core.computer.Computer;
+import dan200.computercraft.core.computer.ITask;
+import dan200.computercraft.core.computer.MainThread;
+
+import javax.annotation.Nonnull;
+
+class CobaltCallContext implements ICallContext
+{
+    private final Computer computer;
+
+    CobaltCallContext( Computer computer )
+    {
+        this.computer = computer;
+    }
+
+    @Override
+    public long issueMainThreadTask( @Nonnull final ILuaTask task ) throws LuaException
+    {
+        // Issue command
+        final long taskID = MainThread.getUniqueTaskID();
+        final ITask iTask = new ITask()
+        {
+            @Override
+            public Computer getOwner()
+            {
+                return computer;
+            }
+
+            @Override
+            public void execute()
+            {
+                try
+                {
+                    Object[] results = task.execute();
+                    if( results != null )
+                    {
+                        Object[] eventArguments = new Object[results.length + 2];
+                        eventArguments[0] = taskID;
+                        eventArguments[1] = true;
+                        System.arraycopy( results, 0, eventArguments, 2, results.length );
+                        computer.queueEvent( "task_complete", eventArguments );
+                    }
+                    else
+                    {
+                        computer.queueEvent( "task_complete", new Object[]{ taskID, true } );
+                    }
+                }
+                catch( LuaException e )
+                {
+                    computer.queueEvent( "task_complete", new Object[]{
+                        taskID, false, e.getMessage()
+                    } );
+                }
+                catch( Throwable t )
+                {
+                    if( ComputerCraft.logPeripheralErrors )
+                    {
+                        ComputerCraft.log.error( "Error running task", t );
+                    }
+                    computer.queueEvent( "task_complete", new Object[]{
+                        taskID, false, "Java Exception Thrown: " + t.toString()
+                    } );
+                }
+            }
+        };
+        if( MainThread.queueTask( iTask ) )
+        {
+            return taskID;
+        }
+        else
+        {
+            throw new LuaException( "Task limit exceeded" );
+        }
+    }
+}

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

@@ -6,39 +6,57 @@
 
 package dan200.computercraft.core.lua;
 
-import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.api.lua.ILuaContext;
+import dan200.computercraft.api.lua.ILuaContextTask;
 import dan200.computercraft.api.lua.ILuaTask;
 import dan200.computercraft.api.lua.LuaException;
 import dan200.computercraft.core.computer.Computer;
-import dan200.computercraft.core.computer.ITask;
-import dan200.computercraft.core.computer.MainThread;
 import org.squiddev.cobalt.LuaError;
 import org.squiddev.cobalt.LuaState;
 import org.squiddev.cobalt.LuaThread;
+import org.squiddev.cobalt.UnwindThrowable;
 
 import javax.annotation.Nonnull;
 import java.lang.ref.WeakReference;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.SynchronousQueue;
+import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
 
-class CobaltLuaContext implements ILuaContext
+/**
+ * An ugly wrapper for {@link ILuaContext} style calls, which executes them on a separate thread.
+ */
+class CobaltLuaContext extends CobaltCallContext implements ILuaContext
 {
-    private final Computer computer;
+    private static final ThreadGroup group = new ThreadGroup( "ComputerCraft-Lua" );
+    private static final AtomicInteger threadCounter = new AtomicInteger();
+    private static final ExecutorService threads = new ThreadPoolExecutor(
+        4, Integer.MAX_VALUE, 60L, TimeUnit.SECONDS, new SynchronousQueue<>(),
+        task -> {
+            Thread thread = new Thread( group, task, group.getName() + "-" + threadCounter.incrementAndGet() );
+            if( !thread.isDaemon() ) thread.setDaemon( true );
+            if( thread.getPriority() != Thread.NORM_PRIORITY ) thread.setPriority( Thread.NORM_PRIORITY );
+            return thread;
+        }
+    );
 
-    boolean done = false;
-    Object[] values;
-    LuaError exception;
-    final Semaphore yield = new Semaphore();
-    final Semaphore resume = new Semaphore();
+    private boolean done = false;
+    private Object[] values;
+    private LuaError exception;
+    private final Semaphore yield = new Semaphore();
+    private final Semaphore resume = new Semaphore();
     private WeakReference<LuaThread> thread;
 
-    public CobaltLuaContext( Computer computer, LuaState state )
+    CobaltLuaContext( Computer computer, LuaState state )
     {
-        this.computer = computer;
+        super( computer );
         this.thread = state.getCurrentThread().getReference();
     }
 
     @Nonnull
     @Override
+    @Deprecated
     public Object[] pullEvent( String filter ) throws LuaException, InterruptedException
     {
         Object[] results = pullEventRaw( filter );
@@ -51,6 +69,7 @@ class CobaltLuaContext implements ILuaContext
 
     @Nonnull
     @Override
+    @Deprecated
     public Object[] pullEventRaw( String filter ) throws InterruptedException
     {
         return yield( new Object[]{ filter } );
@@ -58,6 +77,7 @@ class CobaltLuaContext implements ILuaContext
 
     @Nonnull
     @Override
+    @Deprecated
     public Object[] yield( Object[] yieldArgs ) throws InterruptedException
     {
         if( done ) throw new IllegalStateException( "Cannot yield when complete" );
@@ -76,66 +96,7 @@ class CobaltLuaContext implements ILuaContext
     }
 
     @Override
-    public long issueMainThreadTask( @Nonnull final ILuaTask task ) throws LuaException
-    {
-        // Issue command
-        final long taskID = MainThread.getUniqueTaskID();
-        final ITask iTask = new ITask()
-        {
-            @Override
-            public Computer getOwner()
-            {
-                return computer;
-            }
-
-            @Override
-            public void execute()
-            {
-                try
-                {
-                    Object[] results = task.execute();
-                    if( results != null )
-                    {
-                        Object[] eventArguments = new Object[results.length + 2];
-                        eventArguments[0] = taskID;
-                        eventArguments[1] = true;
-                        System.arraycopy( results, 0, eventArguments, 2, results.length );
-                        computer.queueEvent( "task_complete", eventArguments );
-                    }
-                    else
-                    {
-                        computer.queueEvent( "task_complete", new Object[]{ taskID, true } );
-                    }
-                }
-                catch( LuaException e )
-                {
-                    computer.queueEvent( "task_complete", new Object[]{
-                        taskID, false, e.getMessage()
-                    } );
-                }
-                catch( Throwable t )
-                {
-                    if( ComputerCraft.logPeripheralErrors )
-                    {
-                        ComputerCraft.log.error( "Error running task", t );
-                    }
-                    computer.queueEvent( "task_complete", new Object[]{
-                        taskID, false, "Java Exception Thrown: " + t.toString()
-                    } );
-                }
-            }
-        };
-        if( MainThread.queueTask( iTask ) )
-        {
-            return taskID;
-        }
-        else
-        {
-            throw new LuaException( "Task limit exceeded" );
-        }
-    }
-
-    @Override
+    @Deprecated
     public Object[] executeMainThreadTask( @Nonnull final ILuaTask task ) throws LuaException, InterruptedException
     {
         // Issue task
@@ -172,4 +133,58 @@ class CobaltLuaContext implements ILuaContext
             }
         }
     }
+
+    void execute( ILuaContextTask task )
+    {
+        threads.submit( () -> {
+            try
+            {
+                values = task.execute( this );
+            }
+            catch( LuaException e )
+            {
+                exception = new LuaError( e.getMessage(), e.getLevel() );
+            }
+            catch( InterruptedException e )
+            {
+                exception = new LuaError( "Java Exception Thrown: " + e.toString(), 0 );
+            }
+            finally
+            {
+                done = true;
+                yield.signal();
+            }
+        } );
+    }
+
+    Object[] resume( LuaState state, CobaltLuaMachine machine, Object[] args ) throws LuaError, UnwindThrowable
+    {
+        values = args;
+        resume.signal();
+
+        if( !done )
+        {
+            try
+            {
+                yield.await();
+            }
+            catch( InterruptedException e )
+            {
+                state.debug.onReturn();
+                throw new LuaError( "Java Exception Thrown: " + e.toString(), 0 );
+            }
+        }
+
+        if( done )
+        {
+            state.debug.onReturn();
+            if( exception != null ) throw exception;
+            return values;
+        }
+        else
+        {
+            LuaThread.yield( state, machine.toValues( values ) );
+            throw new IllegalStateException( "Unreachable" );
+        }
+    }
 }

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

@@ -291,20 +291,18 @@ public class CobaltLuaMachine implements ILuaMachine
     {
         LuaTable table = new LuaTable();
         String[] methods = object.getMethodNames();
-        for( int i = 0; i < methods.length; ++i )
+        for( int method = 0; method < methods.length; method++ )
         {
-            if( methods[ i ] != null )
+            if( methods[method] != null )
             {
-                final int method = i;
-                final ILuaObject apiObject = object;
-                final String methodName = methods[ i ];
-                table.rawset( methodName, new CobaltWrapperFunction( this, m_computer, apiObject, method, methodName ) );
+                final String methodName = methods[method];
+                table.rawset( methodName, new CobaltWrapperFunction( this, m_computer, object, method, methodName ) );
             }
         }
         return table;
     }
 
-    LuaValue toValue( Object object, Map<Object, LuaValue> values )
+    private LuaValue toValue( Object object, Map<Object, LuaValue> values )
     {
         if( object == null )
         {
@@ -382,7 +380,7 @@ public class CobaltLuaMachine implements ILuaMachine
         return varargsOf( values );
     }
 
-    static Object toObject( LuaValue value, Map<LuaValue, Object> objects )
+    private static Object toObject( LuaValue value, Map<LuaValue, Object> objects )
     {
         switch( value.type() )
         {

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

@@ -7,8 +7,10 @@
 package dan200.computercraft.core.lua;
 
 import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.api.lua.ILuaFunction;
 import dan200.computercraft.api.lua.ILuaObject;
 import dan200.computercraft.api.lua.LuaException;
+import dan200.computercraft.api.lua.MethodResult;
 import dan200.computercraft.core.computer.Computer;
 import org.squiddev.cobalt.*;
 import org.squiddev.cobalt.debug.DebugFrame;
@@ -16,28 +18,14 @@ import org.squiddev.cobalt.debug.DebugHandler;
 import org.squiddev.cobalt.debug.DebugState;
 import org.squiddev.cobalt.function.VarArgFunction;
 
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.SynchronousQueue;
-import java.util.concurrent.ThreadPoolExecutor;
-import java.util.concurrent.TimeUnit;
-import java.util.concurrent.atomic.AtomicInteger;
+import java.util.ArrayDeque;
+import java.util.Deque;
 
-class CobaltWrapperFunction extends VarArgFunction implements Resumable<CobaltLuaContext>
+class CobaltWrapperFunction extends VarArgFunction implements Resumable<CobaltWrapperFunction.State>
 {
-    private static final ThreadGroup group = new ThreadGroup( "ComputerCraft-Lua" );
-    private static final AtomicInteger threadCounter = new AtomicInteger();
-    private static final ExecutorService threads = new ThreadPoolExecutor(
-        4, Integer.MAX_VALUE, 60L, TimeUnit.SECONDS, new SynchronousQueue<>(),
-        task -> {
-            Thread thread = new Thread( group, task, group.getName() + "-" + threadCounter.incrementAndGet() );
-            if( !thread.isDaemon() ) thread.setDaemon( true );
-            if( thread.getPriority() != Thread.NORM_PRIORITY ) thread.setPriority( Thread.NORM_PRIORITY );
-            return thread;
-        }
-    );
-
     private final CobaltLuaMachine machine;
     private final Computer computer;
+    private final CobaltCallContext callContext;
 
     private final ILuaObject delegate;
     private final int method;
@@ -47,6 +35,7 @@ class CobaltWrapperFunction extends VarArgFunction implements Resumable<CobaltLu
     {
         this.machine = machine;
         this.computer = computer;
+        this.callContext = new CobaltCallContext( computer );
         this.delegate = delegate;
         this.method = method;
         this.methodName = methodName;
@@ -55,94 +44,241 @@ class CobaltWrapperFunction extends VarArgFunction implements Resumable<CobaltLu
     @Override
     public Varargs invoke( final LuaState state, Varargs args ) throws LuaError, UnwindThrowable
     {
-        Object[] arguments = CobaltLuaMachine.toObjects( args, 1 );
-        CobaltLuaContext context = new CobaltLuaContext( computer, state );
-
-        DebugHandler handler = state.debug;
-        DebugState ds = handler.getDebugState();
-        DebugFrame di = handler.onCall( ds, this );
-        di.state = context;
-
-        threads.submit( () -> {
-            try
+        MethodResult future;
+        try
+        {
+            future = delegate.callMethod( callContext, method, CobaltLuaMachine.toObjects( args, 1 ) );
+        }
+        catch( LuaException e )
+        {
+            throw new LuaError( e.getMessage(), e.getLevel() );
+        }
+        catch( Exception e )
+        {
+            if( ComputerCraft.logPeripheralErrors )
             {
-                context.values = delegate.callMethod( context, method, arguments );
+                ComputerCraft.log.error( "Error calling " + methodName + " on " + delegate, e );
             }
-            catch( LuaException e )
+            throw new LuaError( "Java Exception Thrown: " + e.toString(), 0 );
+        }
+
+        if( future == null )
+        {
+            ComputerCraft.log.error( "Null result from " + delegate );
+            throw new LuaError( "Java Exception Thrown: Null result" );
+        }
+
+        State context = new State();
+        try
+        {
+            return runFuture( state, context, future );
+        }
+        catch( UnwindThrowable e )
+        {
+            // Push our state onto the stack if need-be.
+            DebugHandler handler = state.debug;
+            DebugState ds = handler.getDebugState();
+            DebugFrame di = handler.onCall( ds, this );
+            di.state = context;
+
+            throw e;
+        }
+    }
+
+    @Override
+    public Varargs resume( LuaState state, State context, Varargs args ) throws LuaError, UnwindThrowable
+    {
+        try
+        {
+            Varargs result = doResume( state, context, args );
+            state.debug.onReturn();
+            return result;
+        }
+        catch( LuaError e )
+        {
+            state.debug.onReturn();
+            throw e;
+        }
+        catch( Exception e )
+        {
+            state.debug.onReturn();
+            throw new LuaError( e );
+        }
+    }
+
+    private Varargs doResume( LuaState state, State context, Varargs args ) throws LuaError, UnwindThrowable
+    {
+        MethodResult future = context.pending;
+        if( future instanceof MethodResult.OnEvent )
+        {
+            MethodResult.OnEvent onEvent = (MethodResult.OnEvent) future;
+            if( !onEvent.isRaw() && args.first().toString().equals( "terminate" ) )
             {
-                context.exception = new LuaError( e );
+                throw new LuaError( "Terminated", 0 );
             }
-            catch( InterruptedException e )
+
+            return runCallback( state, context, CobaltLuaMachine.toObjects( args, 1 ) );
+        }
+        else if( future instanceof MethodResult.OnMainThread )
+        {
+            if( args.arg( 2 ).isNumber() && args.arg( 3 ).isBoolean() && args.arg( 2 ).toLong() == context.taskId )
             {
-                if( ComputerCraft.logPeripheralErrors )
+                if( args.arg( 3 ).toBoolean() )
                 {
-                    ComputerCraft.log.error( "Error calling " + methodName + " on " + delegate, e );
+                    // Extract the return values from the event and return them
+                    return runCallback( state, context, CobaltLuaMachine.toObjects( args, 4 ) );
+                }
+                else
+                {
+                    // Extract the error message from the event and raise it
+                    throw new LuaError( args.arg( 4 ) );
                 }
-                context.exception = new LuaError( "Java Exception Thrown: " + e.toString(), 0 );
-            }
-            finally
-            {
-                context.done = true;
-                context.yield.signal();
-            }
-        } );
-
-        try
-        {
-            return handleResult( state, context );
-        }
-        catch( InterruptedException e )
-        {
-            throw new LuaError( e );
-        }
-    }
-
-    @Override
-    public Varargs resume( LuaState state, CobaltLuaContext context, Varargs value ) throws LuaError, UnwindThrowable
-    {
-        context.values = CobaltLuaMachine.toObjects( value, 0 );
-        context.resume.signal();
-        try
-        {
-            return handleResult( state, context );
-        }
-        catch( InterruptedException e )
-        {
-            throw new LuaError( e );
-        }
-    }
-
-    @Override
-    public Varargs resumeError( LuaState state, CobaltLuaContext context, LuaError error ) throws LuaError
-    {
-        DebugHandler handler = state.debug;
-        handler.onReturn( handler.getDebugState() );
-        throw error;
-    }
-
-    private Varargs handleResult( LuaState state, CobaltLuaContext context ) throws InterruptedException, LuaError, UnwindThrowable
-    {
-        // We may be done if we yield when handling errors
-        if( !context.done ) context.yield.await();
-
-        if( context.done )
-        {
-            if( context.exception != null )
-            {
-                context.exception.fillTraceback( state );
-                state.debug.onReturn();
-                throw context.exception;
             }
             else
             {
-                state.debug.onReturn();
-                return machine.toValues( context.values );
+                LuaThread.yield( state, ValueFactory.valueOf( "task_complete" ) );
+                throw new IllegalStateException( "Unreachable" );
             }
         }
+        else if( future instanceof MethodResult.WithLuaContext )
+        {
+            return runCallback( state, context, context.luaContext.resume( state, machine, CobaltLuaMachine.toObjects( args, 1 ) ) );
+        }
         else
         {
-            LuaThread.yield( state, machine.toValues( context.values ) );
-            throw new AssertionError( "Unreachable code" );
+            ComputerCraft.log.error( "Unknown method result " + future );
+            throw new LuaError( "Java Exception Thrown: Unknown method result" );
         }
     }
+
+    @Override
+    public Varargs resumeError( LuaState state, State context, LuaError error ) throws LuaError
+    {
+        state.debug.onReturn();
+        throw error;
+    }
+
+    private Varargs runFuture( LuaState state, State context, MethodResult future ) throws LuaError, UnwindThrowable
+    {
+        Deque<ILuaFunction> callbacks = context.callbacks;
+        while( true )
+        {
+            if( future instanceof MethodResult.AndThen )
+            {
+                MethodResult.AndThen then = ((MethodResult.AndThen) future);
+
+                // Thens are "unwrapped", being pushed onto a stack
+                if( callbacks == null ) callbacks = context.callbacks = new ArrayDeque<>();
+                callbacks.addLast( then.getCallback() );
+
+                future = then.getPrevious();
+            }
+            else if( future instanceof MethodResult.Immediate )
+            {
+                Object[] values = ((MethodResult.Immediate) future).getResult();
+
+                // Immediate values values will attempt to call the previous "then", or return if nothing 
+                // else needs to be done.
+                ILuaFunction callback = callbacks == null ? null : callbacks.pollLast();
+                if( callback == null ) return machine.toValues( values );
+
+                future = runFunction( callback, values );
+            }
+            else if( future instanceof MethodResult.OnEvent )
+            {
+                MethodResult.OnEvent onEvent = (MethodResult.OnEvent) future;
+
+                // Mark this future as pending and yield
+                context.pending = future;
+                String filter = onEvent.getFilter();
+                LuaThread.yield( state, filter == null ? Constants.NIL : ValueFactory.valueOf( filter ) );
+                throw new IllegalStateException( "Unreachable" );
+            }
+            else if( future instanceof MethodResult.OnMainThread )
+            {
+                MethodResult.OnMainThread onMainThread = (MethodResult.OnMainThread) future;
+
+                // Mark this future as pending and yield
+                context.pending = future;
+                try
+                {
+                    context.taskId = callContext.issueMainThreadTask( () -> {
+                        context.taskResult = onMainThread.getTask().execute();
+                        return null;
+                    } );
+                }
+                catch( LuaException e )
+                {
+                    throw new LuaError( e.getMessage(), e.getLevel() );
+                }
+
+                LuaThread.yield( state, ValueFactory.valueOf( "task_complete" ) );
+                throw new IllegalStateException( "Unreachable" );
+            }
+            else if( future instanceof MethodResult.WithLuaContext )
+            {
+                MethodResult.WithLuaContext withContext = (MethodResult.WithLuaContext) future;
+
+                // Mark this future as pending and execute on a separate thread.
+                context.pending = future;
+                CobaltLuaContext luaContext = context.luaContext = new CobaltLuaContext( computer, state );
+                luaContext.execute( withContext.getConsumer() );
+            }
+            else
+            {
+                ComputerCraft.log.error( "Unknown method result " + future );
+                throw new LuaError( "Java Exception Thrown: Unknown method result" );
+            }
+        }
+    }
+
+    private Varargs runCallback( LuaState state, State context, Object[] args ) throws LuaError, UnwindThrowable
+    {
+        Deque<ILuaFunction> callbacks = context.callbacks;
+        ILuaFunction callback = callbacks == null ? null : callbacks.pollLast();
+        if( callback == null ) return machine.toValues( args );
+
+        return runFuture( state, context, runFunction( callback, args ) );
+    }
+
+    private MethodResult runFunction( ILuaFunction func, Object[] args ) throws LuaError
+    {
+        MethodResult result;
+        try
+        {
+            result = func.call( args );
+        }
+        catch( LuaException e )
+        {
+            throw new LuaError( e.getMessage(), e.getLevel() );
+        }
+        catch( Exception e )
+        {
+            if( ComputerCraft.logPeripheralErrors )
+            {
+                ComputerCraft.log.error( "Error calling " + methodName + " on " + delegate, e );
+            }
+            throw new LuaError( "Java Exception Thrown: " + e.toString(), 0 );
+        }
+
+        if( result == null )
+        {
+            ComputerCraft.log.error( "Null result from " + func );
+            throw new LuaError( "Java Exception Thrown: Null result" );
+        }
+
+        return result;
+    }
+
+    static class State
+    {
+        Deque<ILuaFunction> callbacks;
+
+        MethodResult pending;
+
+        CobaltLuaContext luaContext;
+
+        long taskId;
+        MethodResult taskResult;
+    }
 }