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
17package androidx.media.filterfw.samples.simplecamera;
18
19import android.os.ConditionVariable;
20import android.os.Handler;
21import android.os.Looper;
22import android.util.Log;
23
24import java.util.concurrent.TimeoutException;
25
26/**
27 * Camera test thread wrapper for handling camera callbacks
28 */
29public 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