| /* |
| * Copyright (C) 2014 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 android.hardware.camera2.legacy; |
| |
| import android.os.ConditionVariable; |
| import android.os.Handler; |
| import android.os.HandlerThread; |
| import android.os.Looper; |
| import android.os.MessageQueue; |
| |
| public class RequestHandlerThread extends HandlerThread { |
| |
| /** |
| * Ensure that the MessageQueue's idle handler gets run by poking the message queue; |
| * normally if the message queue is already idle, the idle handler won't get invoked. |
| * |
| * <p>Users of this handler thread should ignore this message.</p> |
| */ |
| public final static int MSG_POKE_IDLE_HANDLER = -1; |
| |
| private final ConditionVariable mStarted = new ConditionVariable(false); |
| private final ConditionVariable mIdle = new ConditionVariable(true); |
| private Handler.Callback mCallback; |
| private volatile Handler mHandler; |
| |
| public RequestHandlerThread(String name, Handler.Callback callback) { |
| super(name, Thread.MAX_PRIORITY); |
| mCallback = callback; |
| } |
| |
| @Override |
| protected void onLooperPrepared() { |
| mHandler = new Handler(getLooper(), mCallback); |
| mStarted.open(); |
| } |
| |
| // Blocks until thread has started |
| public void waitUntilStarted() { |
| mStarted.block(); |
| } |
| |
| // May return null if the handler is not set up yet. |
| public Handler getHandler() { |
| return mHandler; |
| } |
| |
| // Blocks until thread has started |
| public Handler waitAndGetHandler() { |
| waitUntilStarted(); |
| return getHandler(); |
| } |
| |
| // Atomic multi-type message existence check |
| public boolean hasAnyMessages(int[] what) { |
| synchronized (mHandler.getLooper().getQueue()) { |
| for (int i : what) { |
| if (mHandler.hasMessages(i)) { |
| return true; |
| } |
| } |
| } |
| return false; |
| } |
| |
| // Atomic multi-type message remove |
| public void removeMessages(int[] what) { |
| synchronized (mHandler.getLooper().getQueue()) { |
| for (int i : what) { |
| mHandler.removeMessages(i); |
| } |
| } |
| } |
| |
| private final MessageQueue.IdleHandler mIdleHandler = new MessageQueue.IdleHandler() { |
| @Override |
| public boolean queueIdle() { |
| mIdle.open(); |
| return false; |
| } |
| }; |
| |
| // Blocks until thread is idling |
| public void waitUntilIdle() { |
| Handler handler = waitAndGetHandler(); |
| MessageQueue queue = handler.getLooper().getQueue(); |
| if (queue.isIdle()) { |
| return; |
| } |
| mIdle.close(); |
| queue.addIdleHandler(mIdleHandler); |
| // Ensure that the idle handler gets run even if the looper already went idle |
| handler.sendEmptyMessage(MSG_POKE_IDLE_HANDLER); |
| if (queue.isIdle()) { |
| return; |
| } |
| mIdle.block(); |
| } |
| |
| } |