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      1 /*
      2  * Copyright 2013 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package androidx.media.filterfw.samples.simplecamera;
     18 
     19 import android.os.ConditionVariable;
     20 import android.os.Handler;
     21 import android.os.Looper;
     22 import android.util.Log;
     23 
     24 import java.util.concurrent.TimeoutException;
     25 
     26 /**
     27  * Camera test thread wrapper for handling camera callbacks
     28  */
     29 public class CameraTestThread implements AutoCloseable {
     30     private static final String TAG = "CameraTestThread";
     31     private static final boolean VERBOSE = Log.isLoggable(TAG, Log.VERBOSE);
     32     // Timeout for initializing looper and opening camera in Milliseconds.
     33     private static final long WAIT_FOR_COMMAND_TO_COMPLETE = 5000;
     34     private Looper mLooper = null;
     35     private Handler mHandler = null;
     36 
     37     /**
     38      * Create and start a looper thread, return the Handler
     39      */
     40     public synchronized Handler start() throws Exception {
     41         final ConditionVariable startDone = new ConditionVariable();
     42         if (mLooper != null || mHandler !=null) {
     43             Log.w(TAG, "Looper thread already started");
     44             return mHandler;
     45         }
     46 
     47         new Thread() {
     48             @Override
     49             public void run() {
     50                 if (VERBOSE) Log.v(TAG, "start loopRun");
     51                 Looper.prepare();
     52                 // Save the looper so that we can terminate this thread
     53                 // after we are done with it.
     54                 mLooper = Looper.myLooper();
     55                 mHandler = new Handler();
     56                 startDone.open();
     57                 Looper.loop();
     58                 if (VERBOSE) Log.v(TAG, "createLooperThread: finished");
     59             }
     60         }.start();
     61 
     62         if (VERBOSE) Log.v(TAG, "start waiting for looper");
     63         if (!startDone.block(WAIT_FOR_COMMAND_TO_COMPLETE)) {
     64             throw new TimeoutException("createLooperThread: start timeout");
     65         }
     66         return mHandler;
     67     }
     68 
     69     /**
     70      * Terminate the looper thread
     71      */
     72     public synchronized void close() throws Exception {
     73         if (mLooper == null || mHandler == null) {
     74             Log.w(TAG, "Looper thread doesn't start yet");
     75             return;
     76         }
     77 
     78         if (VERBOSE) Log.v(TAG, "Terminate looper thread");
     79         mLooper.quit();
     80         mLooper.getThread().join();
     81         mLooper = null;
     82         mHandler = null;
     83     }
     84 
     85     @Override
     86     protected void finalize() throws Throwable {
     87         try {
     88             close();
     89         } finally {
     90             super.finalize();
     91         }
     92     }
     93 }
     94