diff options
Diffstat (limited to 'mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/upstream/Loader.java')
| -rw-r--r-- | mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/upstream/Loader.java | 521 |
1 files changed, 521 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/upstream/Loader.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/upstream/Loader.java new file mode 100644 index 0000000000..0e79759b36 --- /dev/null +++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/upstream/Loader.java @@ -0,0 +1,521 @@ +/* + * Copyright (C) 2016 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.mozilla.thirdparty.com.google.android.exoplayer2.upstream; + +import android.annotation.SuppressLint; +import android.os.Handler; +import android.os.Looper; +import android.os.Message; +import android.os.SystemClock; +import androidx.annotation.IntDef; +import androidx.annotation.Nullable; +import org.mozilla.thirdparty.com.google.android.exoplayer2.C; +import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Assertions; +import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Log; +import org.mozilla.thirdparty.com.google.android.exoplayer2.util.TraceUtil; +import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Util; +import java.io.IOException; +import java.lang.annotation.Documented; +import java.lang.annotation.Retention; +import java.lang.annotation.RetentionPolicy; +import java.util.concurrent.ExecutorService; + +/** + * Manages the background loading of {@link Loadable}s. + */ +public final class Loader implements LoaderErrorThrower { + + /** + * Thrown when an unexpected exception or error is encountered during loading. + */ + public static final class UnexpectedLoaderException extends IOException { + + public UnexpectedLoaderException(Throwable cause) { + super("Unexpected " + cause.getClass().getSimpleName() + ": " + cause.getMessage(), cause); + } + + } + + /** + * An object that can be loaded using a {@link Loader}. + */ + public interface Loadable { + + /** + * Cancels the load. + */ + void cancelLoad(); + + /** + * Performs the load, returning on completion or cancellation. + * + * @throws IOException If the input could not be loaded. + * @throws InterruptedException If the thread was interrupted. + */ + void load() throws IOException, InterruptedException; + + } + + /** + * A callback to be notified of {@link Loader} events. + */ + public interface Callback<T extends Loadable> { + + /** + * Called when a load has completed. + * + * <p>Note: There is guaranteed to be a memory barrier between {@link Loadable#load()} exiting + * and this callback being called. + * + * @param loadable The loadable whose load has completed. + * @param elapsedRealtimeMs {@link SystemClock#elapsedRealtime} when the load ended. + * @param loadDurationMs The duration in milliseconds of the load since {@link #startLoading} + * was called. + */ + void onLoadCompleted(T loadable, long elapsedRealtimeMs, long loadDurationMs); + + /** + * Called when a load has been canceled. + * + * <p>Note: If the {@link Loader} has not been released then there is guaranteed to be a memory + * barrier between {@link Loadable#load()} exiting and this callback being called. If the {@link + * Loader} has been released then this callback may be called before {@link Loadable#load()} + * exits. + * + * @param loadable The loadable whose load has been canceled. + * @param elapsedRealtimeMs {@link SystemClock#elapsedRealtime} when the load was canceled. + * @param loadDurationMs The duration in milliseconds of the load since {@link #startLoading} + * was called up to the point at which it was canceled. + * @param released True if the load was canceled because the {@link Loader} was released. False + * otherwise. + */ + void onLoadCanceled(T loadable, long elapsedRealtimeMs, long loadDurationMs, boolean released); + + /** + * Called when a load encounters an error. + * + * <p>Note: There is guaranteed to be a memory barrier between {@link Loadable#load()} exiting + * and this callback being called. + * + * @param loadable The loadable whose load has encountered an error. + * @param elapsedRealtimeMs {@link SystemClock#elapsedRealtime} when the error occurred. + * @param loadDurationMs The duration in milliseconds of the load since {@link #startLoading} + * was called up to the point at which the error occurred. + * @param error The load error. + * @param errorCount The number of errors this load has encountered, including this one. + * @return The desired error handling action. One of {@link Loader#RETRY}, {@link + * Loader#RETRY_RESET_ERROR_COUNT}, {@link Loader#DONT_RETRY}, {@link + * Loader#DONT_RETRY_FATAL} or a retry action created by {@link #createRetryAction}. + */ + LoadErrorAction onLoadError( + T loadable, long elapsedRealtimeMs, long loadDurationMs, IOException error, int errorCount); + } + + /** + * A callback to be notified when a {@link Loader} has finished being released. + */ + public interface ReleaseCallback { + + /** + * Called when the {@link Loader} has finished being released. + */ + void onLoaderReleased(); + + } + + /** Types of action that can be taken in response to a load error. */ + @Documented + @Retention(RetentionPolicy.SOURCE) + @IntDef({ + ACTION_TYPE_RETRY, + ACTION_TYPE_RETRY_AND_RESET_ERROR_COUNT, + ACTION_TYPE_DONT_RETRY, + ACTION_TYPE_DONT_RETRY_FATAL + }) + private @interface RetryActionType {} + + private static final int ACTION_TYPE_RETRY = 0; + private static final int ACTION_TYPE_RETRY_AND_RESET_ERROR_COUNT = 1; + private static final int ACTION_TYPE_DONT_RETRY = 2; + private static final int ACTION_TYPE_DONT_RETRY_FATAL = 3; + + /** Retries the load using the default delay. */ + public static final LoadErrorAction RETRY = + createRetryAction(/* resetErrorCount= */ false, C.TIME_UNSET); + /** Retries the load using the default delay and resets the error count. */ + public static final LoadErrorAction RETRY_RESET_ERROR_COUNT = + createRetryAction(/* resetErrorCount= */ true, C.TIME_UNSET); + /** Discards the failed {@link Loadable} and ignores any errors that have occurred. */ + public static final LoadErrorAction DONT_RETRY = + new LoadErrorAction(ACTION_TYPE_DONT_RETRY, C.TIME_UNSET); + /** + * Discards the failed {@link Loadable}. The next call to {@link #maybeThrowError()} will throw + * the last load error. + */ + public static final LoadErrorAction DONT_RETRY_FATAL = + new LoadErrorAction(ACTION_TYPE_DONT_RETRY_FATAL, C.TIME_UNSET); + + /** + * Action that can be taken in response to {@link Callback#onLoadError(Loadable, long, long, + * IOException, int)}. + */ + public static final class LoadErrorAction { + + private final @RetryActionType int type; + private final long retryDelayMillis; + + private LoadErrorAction(@RetryActionType int type, long retryDelayMillis) { + this.type = type; + this.retryDelayMillis = retryDelayMillis; + } + + /** Returns whether this is a retry action. */ + public boolean isRetry() { + return type == ACTION_TYPE_RETRY || type == ACTION_TYPE_RETRY_AND_RESET_ERROR_COUNT; + } + } + + private final ExecutorService downloadExecutorService; + + @Nullable private LoadTask<? extends Loadable> currentTask; + @Nullable private IOException fatalError; + + /** + * @param threadName A name for the loader's thread. + */ + public Loader(String threadName) { + this.downloadExecutorService = Util.newSingleThreadExecutor(threadName); + } + + /** + * Creates a {@link LoadErrorAction} for retrying with the given parameters. + * + * @param resetErrorCount Whether the previous error count should be set to zero. + * @param retryDelayMillis The number of milliseconds to wait before retrying. + * @return A {@link LoadErrorAction} for retrying with the given parameters. + */ + public static LoadErrorAction createRetryAction(boolean resetErrorCount, long retryDelayMillis) { + return new LoadErrorAction( + resetErrorCount ? ACTION_TYPE_RETRY_AND_RESET_ERROR_COUNT : ACTION_TYPE_RETRY, + retryDelayMillis); + } + + /** + * Whether the last call to {@link #startLoading} resulted in a fatal error. Calling {@link + * #maybeThrowError()} will throw the fatal error. + */ + public boolean hasFatalError() { + return fatalError != null; + } + + /** Clears any stored fatal error. */ + public void clearFatalError() { + fatalError = null; + } + + /** + * Starts loading a {@link Loadable}. + * + * <p>The calling thread must be a {@link Looper} thread, which is the thread on which the {@link + * Callback} will be called. + * + * @param <T> The type of the loadable. + * @param loadable The {@link Loadable} to load. + * @param callback A callback to be called when the load ends. + * @param defaultMinRetryCount The minimum number of times the load must be retried before {@link + * #maybeThrowError()} will propagate an error. + * @throws IllegalStateException If the calling thread does not have an associated {@link Looper}. + * @return {@link SystemClock#elapsedRealtime} when the load started. + */ + public <T extends Loadable> long startLoading( + T loadable, Callback<T> callback, int defaultMinRetryCount) { + Looper looper = Assertions.checkStateNotNull(Looper.myLooper()); + fatalError = null; + long startTimeMs = SystemClock.elapsedRealtime(); + new LoadTask<>(looper, loadable, callback, defaultMinRetryCount, startTimeMs).start(0); + return startTimeMs; + } + + /** Returns whether the loader is currently loading. */ + public boolean isLoading() { + return currentTask != null; + } + + /** + * Cancels the current load. + * + * @throws IllegalStateException If the loader is not currently loading. + */ + public void cancelLoading() { + Assertions.checkStateNotNull(currentTask).cancel(false); + } + + /** Releases the loader. This method should be called when the loader is no longer required. */ + public void release() { + release(null); + } + + /** + * Releases the loader. This method should be called when the loader is no longer required. + * + * @param callback An optional callback to be called on the loading thread once the loader has + * been released. + */ + public void release(@Nullable ReleaseCallback callback) { + if (currentTask != null) { + currentTask.cancel(true); + } + if (callback != null) { + downloadExecutorService.execute(new ReleaseTask(callback)); + } + downloadExecutorService.shutdown(); + } + + // LoaderErrorThrower implementation. + + @Override + public void maybeThrowError() throws IOException { + maybeThrowError(Integer.MIN_VALUE); + } + + @Override + public void maybeThrowError(int minRetryCount) throws IOException { + if (fatalError != null) { + throw fatalError; + } else if (currentTask != null) { + currentTask.maybeThrowError(minRetryCount == Integer.MIN_VALUE + ? currentTask.defaultMinRetryCount : minRetryCount); + } + } + + // Internal classes. + + @SuppressLint("HandlerLeak") + private final class LoadTask<T extends Loadable> extends Handler implements Runnable { + + private static final String TAG = "LoadTask"; + + private static final int MSG_START = 0; + private static final int MSG_CANCEL = 1; + private static final int MSG_END_OF_SOURCE = 2; + private static final int MSG_IO_EXCEPTION = 3; + private static final int MSG_FATAL_ERROR = 4; + + public final int defaultMinRetryCount; + + private final T loadable; + private final long startTimeMs; + + @Nullable private Loader.Callback<T> callback; + @Nullable private IOException currentError; + private int errorCount; + + @Nullable private volatile Thread executorThread; + private volatile boolean canceled; + private volatile boolean released; + + public LoadTask(Looper looper, T loadable, Loader.Callback<T> callback, + int defaultMinRetryCount, long startTimeMs) { + super(looper); + this.loadable = loadable; + this.callback = callback; + this.defaultMinRetryCount = defaultMinRetryCount; + this.startTimeMs = startTimeMs; + } + + public void maybeThrowError(int minRetryCount) throws IOException { + if (currentError != null && errorCount > minRetryCount) { + throw currentError; + } + } + + public void start(long delayMillis) { + Assertions.checkState(currentTask == null); + currentTask = this; + if (delayMillis > 0) { + sendEmptyMessageDelayed(MSG_START, delayMillis); + } else { + execute(); + } + } + + public void cancel(boolean released) { + this.released = released; + currentError = null; + if (hasMessages(MSG_START)) { + removeMessages(MSG_START); + if (!released) { + sendEmptyMessage(MSG_CANCEL); + } + } else { + canceled = true; + loadable.cancelLoad(); + Thread executorThread = this.executorThread; + if (executorThread != null) { + executorThread.interrupt(); + } + } + if (released) { + finish(); + long nowMs = SystemClock.elapsedRealtime(); + Assertions.checkNotNull(callback) + .onLoadCanceled(loadable, nowMs, nowMs - startTimeMs, true); + // If loading, this task will be referenced from a GC root (the loading thread) until + // cancellation completes. The time taken for cancellation to complete depends on the + // implementation of the Loadable that the task is loading. We null the callback reference + // here so that it doesn't prevent garbage collection whilst cancellation is ongoing. + callback = null; + } + } + + @Override + public void run() { + try { + executorThread = Thread.currentThread(); + if (!canceled) { + TraceUtil.beginSection("load:" + loadable.getClass().getSimpleName()); + try { + loadable.load(); + } finally { + TraceUtil.endSection(); + } + } + if (!released) { + sendEmptyMessage(MSG_END_OF_SOURCE); + } + } catch (IOException e) { + if (!released) { + obtainMessage(MSG_IO_EXCEPTION, e).sendToTarget(); + } + } catch (InterruptedException e) { + // The load was canceled. + Assertions.checkState(canceled); + if (!released) { + sendEmptyMessage(MSG_END_OF_SOURCE); + } + } catch (Exception e) { + // This should never happen, but handle it anyway. + Log.e(TAG, "Unexpected exception loading stream", e); + if (!released) { + obtainMessage(MSG_IO_EXCEPTION, new UnexpectedLoaderException(e)).sendToTarget(); + } + } catch (OutOfMemoryError e) { + // This can occur if a stream is malformed in a way that causes an extractor to think it + // needs to allocate a large amount of memory. We don't want the process to die in this + // case, but we do want the playback to fail. + Log.e(TAG, "OutOfMemory error loading stream", e); + if (!released) { + obtainMessage(MSG_IO_EXCEPTION, new UnexpectedLoaderException(e)).sendToTarget(); + } + } catch (Error e) { + // We'd hope that the platform would kill the process if an Error is thrown here, but the + // executor may catch the error (b/20616433). Throw it here, but also pass and throw it from + // the handler thread so that the process dies even if the executor behaves in this way. + Log.e(TAG, "Unexpected error loading stream", e); + if (!released) { + obtainMessage(MSG_FATAL_ERROR, e).sendToTarget(); + } + throw e; + } + } + + @Override + public void handleMessage(Message msg) { + if (released) { + return; + } + if (msg.what == MSG_START) { + execute(); + return; + } + if (msg.what == MSG_FATAL_ERROR) { + throw (Error) msg.obj; + } + finish(); + long nowMs = SystemClock.elapsedRealtime(); + long durationMs = nowMs - startTimeMs; + Loader.Callback<T> callback = Assertions.checkNotNull(this.callback); + if (canceled) { + callback.onLoadCanceled(loadable, nowMs, durationMs, false); + return; + } + switch (msg.what) { + case MSG_CANCEL: + callback.onLoadCanceled(loadable, nowMs, durationMs, false); + break; + case MSG_END_OF_SOURCE: + try { + callback.onLoadCompleted(loadable, nowMs, durationMs); + } catch (RuntimeException e) { + // This should never happen, but handle it anyway. + Log.e(TAG, "Unexpected exception handling load completed", e); + fatalError = new UnexpectedLoaderException(e); + } + break; + case MSG_IO_EXCEPTION: + currentError = (IOException) msg.obj; + errorCount++; + LoadErrorAction action = + callback.onLoadError(loadable, nowMs, durationMs, currentError, errorCount); + if (action.type == ACTION_TYPE_DONT_RETRY_FATAL) { + fatalError = currentError; + } else if (action.type != ACTION_TYPE_DONT_RETRY) { + if (action.type == ACTION_TYPE_RETRY_AND_RESET_ERROR_COUNT) { + errorCount = 1; + } + start( + action.retryDelayMillis != C.TIME_UNSET + ? action.retryDelayMillis + : getRetryDelayMillis()); + } + break; + default: + // Never happens. + break; + } + } + + private void execute() { + currentError = null; + downloadExecutorService.execute(Assertions.checkNotNull(currentTask)); + } + + private void finish() { + currentTask = null; + } + + private long getRetryDelayMillis() { + return Math.min((errorCount - 1) * 1000, 5000); + } + + } + + private static final class ReleaseTask implements Runnable { + + private final ReleaseCallback callback; + + public ReleaseTask(ReleaseCallback callback) { + this.callback = callback; + } + + @Override + public void run() { + callback.onLoaderReleased(); + } + + } + +} |