diff options
Diffstat (limited to 'mobile/android/geckoview/src/main/java/org/mozilla/gecko/EventDispatcher.java')
| -rw-r--r-- | mobile/android/geckoview/src/main/java/org/mozilla/gecko/EventDispatcher.java | 588 |
1 files changed, 588 insertions, 0 deletions
diff --git a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/EventDispatcher.java b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/EventDispatcher.java new file mode 100644 index 0000000000..647ac5bc09 --- /dev/null +++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/EventDispatcher.java @@ -0,0 +1,588 @@ +/* -*- Mode: Java; c-basic-offset: 4; tab-width: 4; indent-tabs-mode: nil; -*- + * vim: ts=4 sw=4 expandtab: +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +package org.mozilla.gecko; + +import android.os.Handler; +import android.util.Log; +import androidx.annotation.AnyThread; +import java.util.ArrayDeque; +import java.util.Arrays; +import java.util.Deque; +import java.util.HashMap; +import java.util.HashSet; +import java.util.Map; +import java.util.Set; +import org.mozilla.gecko.annotation.ReflectionTarget; +import org.mozilla.gecko.annotation.RobocopTarget; +import org.mozilla.gecko.annotation.WrapForJNI; +import org.mozilla.gecko.mozglue.JNIObject; +import org.mozilla.gecko.util.BundleEventListener; +import org.mozilla.gecko.util.EventCallback; +import org.mozilla.gecko.util.GeckoBundle; +import org.mozilla.gecko.util.ThreadUtils; +import org.mozilla.geckoview.BuildConfig; +import org.mozilla.geckoview.GeckoResult; + +@RobocopTarget +public final class EventDispatcher extends JNIObject { + private static final String LOGTAG = "GeckoEventDispatcher"; + + private static final EventDispatcher INSTANCE = new EventDispatcher(); + + /** + * The capacity of a HashMap is rounded up to the next power-of-2. Every time the size of the map + * goes beyond 75% of the capacity, the map is rehashed. Therefore, to empirically determine the + * initial capacity that avoids rehashing, we need to determine the initial size, divide it by + * 75%, and round up to the next power-of-2. + */ + private static final int DEFAULT_UI_EVENTS_COUNT = 128; // Empirically measured + + private static class Message { + final String type; + final GeckoBundle bundle; + final EventCallback callback; + + Message(final String type, final GeckoBundle bundle, final EventCallback callback) { + this.type = type; + this.bundle = bundle; + this.callback = callback; + } + } + + // GeckoBundle-based events. + private final MultiMap<String, BundleEventListener> mListeners = + new MultiMap<>(DEFAULT_UI_EVENTS_COUNT); + private Deque<Message> mPendingMessages = new ArrayDeque<>(); + + private boolean mAttachedToGecko; + private final NativeQueue mNativeQueue; + private final String mName; + + private static Map<String, EventDispatcher> sDispatchers = new HashMap<>(); + + @ReflectionTarget + @WrapForJNI(calledFrom = "gecko") + public static EventDispatcher getInstance() { + return INSTANCE; + } + + /** + * Gets a named EventDispatcher. + * + * <p>Named EventDispatchers can be used to communicate to Gecko's corresponding named + * EventDispatcher. + * + * <p>Messages for named EventDispatcher are queued by default when no listener is present. Queued + * messages will be released automatically when a listener is attached. + * + * <p>A named EventDispatcher needs to be disposed manually by calling {@link #shutdown} when it + * is not needed anymore. + * + * @param name Name for this EventDispatcher. + * @return the existing named EventDispatcher for a given name or a newly created one if it + * doesn't exist. + */ + @ReflectionTarget + @WrapForJNI(calledFrom = "gecko") + public static EventDispatcher byName(final String name) { + synchronized (sDispatchers) { + EventDispatcher dispatcher = sDispatchers.get(name); + + if (dispatcher == null) { + dispatcher = new EventDispatcher(name); + sDispatchers.put(name, dispatcher); + } + + return dispatcher; + } + } + + /* package */ EventDispatcher() { + mNativeQueue = GeckoThread.getNativeQueue(); + mName = null; + } + + /* package */ EventDispatcher(final String name) { + mNativeQueue = GeckoThread.getNativeQueue(); + mName = name; + } + + public EventDispatcher(final NativeQueue queue) { + mNativeQueue = queue; + mName = null; + } + + private boolean isReadyForDispatchingToGecko() { + return mNativeQueue.isReady(); + } + + @WrapForJNI + @Override // JNIObject + protected native void disposeNative(); + + @WrapForJNI(stubName = "Shutdown") + protected native void shutdownNative(); + + @WrapForJNI private static final int DETACHED = 0; + @WrapForJNI private static final int ATTACHED = 1; + @WrapForJNI private static final int REATTACHING = 2; + + @WrapForJNI(calledFrom = "gecko") + private synchronized void setAttachedToGecko(final int state) { + if (mAttachedToGecko && state == DETACHED) { + dispose(false); + } + mAttachedToGecko = (state == ATTACHED); + } + + /** + * Shuts down this EventDispatcher and release resources. + * + * <p>Only named EventDispatcher can be shut down manually. A shut down EventDispatcher will not + * receive any further messages. + */ + public void shutdown() { + if (mName == null) { + throw new RuntimeException("Only named EventDispatcher's can be shut down."); + } + + mAttachedToGecko = false; + shutdownNative(); + dispose(false); + + synchronized (sDispatchers) { + sDispatchers.put(mName, null); + } + } + + private void dispose(final boolean force) { + final Handler geckoHandler = ThreadUtils.sGeckoHandler; + if (geckoHandler == null) { + return; + } + + geckoHandler.post( + new Runnable() { + @Override + public void run() { + if (force || !mAttachedToGecko) { + disposeNative(); + } + } + }); + } + + public void registerUiThreadListener(final BundleEventListener listener, final String... events) { + try { + synchronized (mListeners) { + for (final String event : events) { + if (!BuildConfig.RELEASE_OR_BETA && mListeners.containsEntry(event, listener)) { + throw new IllegalStateException("Already registered " + event); + } + mListeners.add(event, listener); + } + flush(events); + } + } catch (final Exception e) { + throw new IllegalArgumentException("Invalid new list type", e); + } + } + + public void unregisterUiThreadListener( + final BundleEventListener listener, final String... events) { + synchronized (mListeners) { + for (final String event : events) { + if (!mListeners.remove(event, listener) && !BuildConfig.RELEASE_OR_BETA) { + throw new IllegalArgumentException(event + " was not registered"); + } + } + } + } + + @WrapForJNI + private native boolean hasGeckoListener(final String event); + + @WrapForJNI(dispatchTo = "gecko") + private native void dispatchToGecko( + final String event, final GeckoBundle data, final EventCallback callback); + + /** + * Dispatch event to any registered Bundle listeners (non-Gecko thread listeners). + * + * @param type Event type + * @param message Bundle message + */ + public void dispatch(final String type, final GeckoBundle message) { + dispatch(type, message, /* callback */ null); + } + + private abstract class CallbackResult<T> extends GeckoResult<T> implements EventCallback { + @Override + public void sendError(final Object response) { + completeExceptionally(new QueryException(response)); + } + } + + public class QueryException extends Exception { + public final Object data; + + public QueryException(final Object data) { + this.data = data; + } + } + + /** + * Query event to any registered Bundle listeners (non-Gecko thread listeners). + * + * <p>The returned GeckoResult completes when the event handler returns. + * + * @param type Event type + */ + public GeckoResult<Void> queryVoid(final String type) { + return queryVoid(type, null); + } + + /** + * Query event to any registered Bundle listeners (non-Gecko thread listeners). + * + * <p>The returned GeckoResult completes when the event handler returns. + * + * @param type Event type + * @param message GeckoBundle message + */ + public GeckoResult<Void> queryVoid(final String type, final GeckoBundle message) { + return query(type, message); + } + + /** + * Query event to any registered Bundle listeners (non-Gecko thread listeners). + * + * <p>The returned GeckoResult completes with the given boolean value returned by the handler. + * + * @param type Event type + */ + public GeckoResult<Boolean> queryBoolean(final String type) { + return queryBoolean(type, null); + } + + /** + * Query event to any registered Bundle listeners (non-Gecko thread listeners). + * + * <p>The returned GeckoResult completes with the given boolean value returned by the handler. + * + * @param type Event type + * @param message GeckoBundle message + */ + public GeckoResult<Boolean> queryBoolean(final String type, final GeckoBundle message) { + return query(type, message); + } + + /** + * Query event to any registered Bundle listeners (non-Gecko thread listeners). + * + * <p>The returned GeckoResult completes with the given String value returned by the handler. + * + * @param type Event type + */ + public GeckoResult<String> queryString(final String type) { + return queryString(type, null); + } + + /** + * Query event to any registered Bundle listeners (non-Gecko thread listeners). + * + * <p>The returned GeckoResult completes with the given String value returned by the handler. + * + * @param type Event type + * @param message GeckoBundle message + */ + public GeckoResult<String> queryString(final String type, final GeckoBundle message) { + return query(type, message); + } + + /** + * Query event to any registered Bundle listeners (non-Gecko thread listeners). + * + * <p>The returned GeckoResult completes with the given {@link GeckoBundle} value returned by the + * handler. + * + * @param type Event type + */ + public GeckoResult<GeckoBundle> queryBundle(final String type) { + return queryBundle(type, null); + } + + /** + * Query event to any registered Bundle listeners (non-Gecko thread listeners). + * + * <p>The returned GeckoResult completes with the given {@link GeckoBundle} value returned by the + * handler. + * + * @param type Event type + * @param message GeckoBundle message + */ + public GeckoResult<GeckoBundle> queryBundle(final String type, final GeckoBundle message) { + return query(type, message); + } + + private <T> GeckoResult<T> query(final String type, final GeckoBundle message) { + final CallbackResult<T> result = + new CallbackResult<T>() { + @Override + @SuppressWarnings("unchecked") // Not a lot we can do about this :( + public void sendSuccess(final Object response) { + complete((T) response); + } + }; + + dispatch(type, message, result); + return result; + } + + /** + * Flushes pending messages of given types. + * + * <p>All unhandled messages are put into a pending state by default for named EventDispatcher + * obtained from {@link #byName}. + * + * @param types Types of message to flush. + */ + private void flush(final String[] types) { + final Set<String> typeSet = new HashSet<>(Arrays.asList(types)); + + final Deque<Message> pendingMessages; + synchronized (mPendingMessages) { + pendingMessages = mPendingMessages; + mPendingMessages = new ArrayDeque<>(pendingMessages.size()); + } + + Message message; + while (!pendingMessages.isEmpty()) { + message = pendingMessages.removeFirst(); + if (typeSet.contains(message.type)) { + dispatchToThreads(message.type, message.bundle, message.callback); + } else { + synchronized (mPendingMessages) { + mPendingMessages.addLast(message); + } + } + } + } + + /** + * Dispatch event to any registered Bundle listeners (non-Gecko thread listeners). + * + * @param type Event type + * @param message Bundle message + * @param callback Optional object for callbacks from events. + */ + @AnyThread + private void dispatch( + final String type, final GeckoBundle message, final EventCallback callback) { + final boolean isGeckoReady; + synchronized (this) { + isGeckoReady = isReadyForDispatchingToGecko(); + if (isGeckoReady && mAttachedToGecko && hasGeckoListener(type)) { + dispatchToGecko(type, message, JavaCallbackDelegate.wrap(callback)); + return; + } + } + + dispatchToThreads(type, message, callback, isGeckoReady); + } + + @WrapForJNI(calledFrom = "gecko") + private boolean dispatchToThreads( + final String type, final GeckoBundle message, final EventCallback callback) { + return dispatchToThreads(type, message, callback, /* isGeckoReady */ true); + } + + private boolean dispatchToThreads( + final String type, + final GeckoBundle message, + final EventCallback callback, + final boolean isGeckoReady) { + // We need to hold the lock throughout dispatching, to ensure the listeners list + // is consistent, while we iterate over it. We don't have to worry about listeners + // running for a long time while we have the lock, because the listeners will run + // on a separate thread. + synchronized (mListeners) { + if (mListeners.containsKey(type)) { + // Use a delegate to make sure callbacks happen on a specific thread. + final EventCallback wrappedCallback = JavaCallbackDelegate.wrap(callback); + + // Event listeners will call | callback.sendError | if applicable. + for (final BundleEventListener listener : mListeners.get(type)) { + ThreadUtils.getUiHandler() + .post( + new Runnable() { + @Override + public void run() { + final Double startTime = GeckoJavaSampler.tryToGetProfilerTime(); + listener.handleMessage(type, message, wrappedCallback); + GeckoJavaSampler.addMarker( + "EventDispatcher handleMessage", startTime, null, type); + } + }); + } + return true; + } + } + + if (!isGeckoReady) { + // Usually, we discard an event if there is no listeners for it by + // the time of the dispatch. However, if Gecko(View) is not ready and + // there is no listener for this event that's possibly headed to + // Gecko, we make a special exception to queue this event until + // Gecko(View) is ready. This way, Gecko can first register its + // listeners, and accept the event when it is ready. + mNativeQueue.queueUntilReady( + this, + "dispatchToGecko", + String.class, + type, + GeckoBundle.class, + message, + EventCallback.class, + JavaCallbackDelegate.wrap(callback)); + return true; + } + + // Named EventDispatchers use pending messages + if (mName != null) { + synchronized (mPendingMessages) { + mPendingMessages.addLast(new Message(type, message, callback)); + } + return true; + } + + final String error = "No listener for " + type; + if (callback != null) { + callback.sendError(error); + } + + Log.w(LOGTAG, error); + return false; + } + + @WrapForJNI + public boolean hasListener(final String event) { + synchronized (mListeners) { + return mListeners.containsKey(event); + } + } + + @Override + protected void finalize() throws Throwable { + dispose(true); + } + + private static class NativeCallbackDelegate extends JNIObject implements EventCallback { + @WrapForJNI(calledFrom = "gecko") + private NativeCallbackDelegate() {} + + @Override // JNIObject + protected void disposeNative() { + // We dispose in finalize(). + throw new UnsupportedOperationException(); + } + + @WrapForJNI(dispatchTo = "proxy") + @Override // EventCallback + public native void sendSuccess(Object response); + + @WrapForJNI(dispatchTo = "proxy") + @Override // EventCallback + public native void sendError(Object response); + + @WrapForJNI(dispatchTo = "gecko") + @Override // Object + protected native void finalize(); + } + + private static class JavaCallbackDelegate implements EventCallback { + private final Thread mOriginalThread = Thread.currentThread(); + private final EventCallback mCallback; + + public static EventCallback wrap(final EventCallback callback) { + if (callback == null) { + return null; + } + if (callback instanceof NativeCallbackDelegate) { + // NativeCallbackDelegate always posts to Gecko thread if needed. + return callback; + } + return new JavaCallbackDelegate(callback); + } + + JavaCallbackDelegate(final EventCallback callback) { + mCallback = callback; + } + + private void makeCallback(final boolean callSuccess, final Object rawResponse) { + final Object response; + if (rawResponse instanceof Number) { + // There is ambiguity because a number can be converted to either int or + // double, so e.g. the user can be expecting a double when we give it an + // int. To avoid these pitfalls, we disallow all numbers. The workaround + // is to wrap the number in a JS object / GeckoBundle, which supports + // type coersion for numbers. + throw new UnsupportedOperationException("Cannot use number as Java callback result"); + } else if (rawResponse != null && rawResponse.getClass().isArray()) { + // Same with arrays. + throw new UnsupportedOperationException("Cannot use arrays as Java callback result"); + } else if (rawResponse instanceof Character) { + response = rawResponse.toString(); + } else { + response = rawResponse; + } + + // Call back synchronously if we happen to be on the same thread as the thread + // making the original request. + if (ThreadUtils.isOnThread(mOriginalThread)) { + if (callSuccess) { + mCallback.sendSuccess(response); + } else { + mCallback.sendError(response); + } + return; + } + + // Make callback on the thread of the original request, if the original thread + // is the UI or Gecko thread. Otherwise default to the background thread. + final Handler handler = + mOriginalThread == ThreadUtils.getUiThread() + ? ThreadUtils.getUiHandler() + : mOriginalThread == ThreadUtils.sGeckoThread + ? ThreadUtils.sGeckoHandler + : ThreadUtils.getBackgroundHandler(); + final EventCallback callback = mCallback; + + handler.post( + new Runnable() { + @Override + public void run() { + if (callSuccess) { + callback.sendSuccess(response); + } else { + callback.sendError(response); + } + } + }); + } + + @Override // EventCallback + public void sendSuccess(final Object response) { + makeCallback(/* success */ true, response); + } + + @Override // EventCallback + public void sendError(final Object response) { + makeCallback(/* success */ false, response); + } + } +} |