Make the fuchsia mojo/public repo the source of truth.

mojo/public/java/bindings/src/org/chromium/mojo/bindings/ExecutorFactory.java

-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-package org.chromium.mojo.bindings;
-
-import org.chromium.mojo.system.AsyncWaiter;
-import org.chromium.mojo.system.AsyncWaiter.Callback;
-import org.chromium.mojo.system.Core;
-import org.chromium.mojo.system.MessagePipeHandle;
-import org.chromium.mojo.system.MessagePipeHandle.ReadMessageResult;
-import org.chromium.mojo.system.MojoException;
-import org.chromium.mojo.system.MojoResult;
-import org.chromium.mojo.system.Pair;
-import org.chromium.mojo.system.ResultAnd;
-
-import java.nio.ByteBuffer;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.concurrent.Executor;
-
-/**
- * A factory which provides per-thread executors, which enable execution on the thread from which
- * they were obtained.
- */
-class ExecutorFactory {
-
-    /**
-     * A null buffer which is used to send messages without any data on the PipedExecutor's
-     * signaling handles.
-     */
-    private static final ByteBuffer NOTIFY_BUFFER = null;
-
-    /**
-     * Implementation of the executor which uses a pair of {@link MessagePipeHandle} for signaling.
-     * The executor will wait asynchronously on one end of a {@link MessagePipeHandle} on the thread
-     * on which it was created. Other threads can call execute with a {@link Runnable}, and the
-     * executor will queue the {@link Runnable} and write a message on the other end of the handle.
-     * This will wake up the executor which is waiting on the handle, which will then dequeue the
-     * {@link Runnable} and execute it on the original thread.
-     */
-    private static class PipedExecutor implements Executor, Callback {
-
-        /**
-         * The handle which is written to. Access to this object must be protected with |mLock|.
-         */
-        private final MessagePipeHandle mWriteHandle;
-        /**
-         * The handle which is read from.
-         */
-        private final MessagePipeHandle mReadHandle;
-        /**
-         * The list of actions left to be run. Access to this object must be protected with |mLock|.
-         */
-        private final List<Runnable> mPendingActions;
-        /**
-         * Lock protecting access to |mWriteHandle| and |mPendingActions|.
-         */
-        private final Object mLock;
-        /**
-         * The {@link AsyncWaiter} to get notified of new message availability on |mReadHandle|.
-         */
-        private final AsyncWaiter mWaiter;
-
-        /**
-         * Constructor.
-         */
-        public PipedExecutor(Core core) {
-            mWaiter = core.getDefaultAsyncWaiter();
-            assert mWaiter != null;
-            mLock = new Object();
-            Pair<MessagePipeHandle, MessagePipeHandle> handles = core.createMessagePipe(
-                    new MessagePipeHandle.CreateOptions());
-            mReadHandle = handles.first;
-            mWriteHandle = handles.second;
-            mPendingActions = new ArrayList<Runnable>();
-            asyncWait();
-        }
-
-        /**
-         * Asynchronously wait for the next command to arrive. This should only be called on the
-         * executor thread.
-         */
-        private void asyncWait() {
-            mWaiter.asyncWait(mReadHandle, Core.HandleSignals.READABLE, Core.DEADLINE_INFINITE,
-                    this);
-        }
-
-        /**
-         * @see Callback#onResult(int)
-         */
-        @Override
-        public void onResult(int result) {
-            if (result == MojoResult.OK && readNotifyBufferMessage()) {
-                runNextAction();
-            } else {
-                close();
-            }
-        }
-
-        /**
-         * @see Callback#onError(MojoException)
-         */
-        @Override
-        public void onError(MojoException exception) {
-            close();
-        }
-
-        /**
-         * Close the handles. Should only be called on the executor thread.
-         */
-        private void close() {
-            synchronized (mLock) {
-                mWriteHandle.close();
-                mPendingActions.clear();
-            }
-            mReadHandle.close();
-        }
-
-        /**
-         * Read the next message on |mReadHandle|, and return |true| if successful, |false|
-         * otherwise.
-         */
-        private boolean readNotifyBufferMessage() {
-            try {
-                ResultAnd<ReadMessageResult> readMessageResult =
-                        mReadHandle.readMessage(NOTIFY_BUFFER, 0, MessagePipeHandle.ReadFlags.NONE);
-                if (readMessageResult.getMojoResult() == MojoResult.OK) {
-                    asyncWait();
-                    return true;
-                }
-            } catch (MojoException e) {
-                // Will be closed by the fall back at the end of this method.
-            }
-            return false;
-        }
-
-        /**
-         * Run the next action in the |mPendingActions| queue.
-         */
-        private void runNextAction() {
-            Runnable toRun = null;
-            synchronized (mLock) {
-                toRun = mPendingActions.remove(0);
-            }
-            toRun.run();
-        }
-
-        /**
-         * Execute the given |command| in the executor thread. This can be called on any thread.
-         *
-         * @see Executor#execute(Runnable)
-         */
-        @Override
-        public void execute(Runnable command) {
-            // Accessing the write handle must be protected by the lock, because it can be closed
-            // from the executor's thread.
-            synchronized (mLock) {
-                if (!mWriteHandle.isValid()) {
-                    throw new IllegalStateException(
-                            "Trying to execute an action on a closed executor.");
-                }
-                mPendingActions.add(command);
-                mWriteHandle.writeMessage(NOTIFY_BUFFER, null, MessagePipeHandle.WriteFlags.NONE);
-            }
-        }
-    }
-
-    /**
-     * Keep one executor per executor thread.
-     */
-    private static final ThreadLocal<Executor> EXECUTORS = new ThreadLocal<Executor>();
-
-    /**
-     * Returns an {@link Executor} that will run all of its actions in the current thread.
-     */
-    public static Executor getExecutorForCurrentThread(Core core) {
-        Executor executor = EXECUTORS.get();
-        if (executor == null) {
-            executor = new PipedExecutor(core);
-            EXECUTORS.set(executor);
-        }
-        return executor;
-    }
-}