1/*
2 * Copyright (C) 2014 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 com.android.ex.camera2.portability;
18
19import android.os.Handler;
20import android.os.HandlerThread;
21import android.os.SystemClock;
22
23import com.android.ex.camera2.portability.debug.Log;
24
25import java.util.LinkedList;
26import java.util.Queue;
27
28public class DispatchThread extends Thread {
29    private static final Log.Tag TAG = new Log.Tag("DispatchThread");
30    private static final long MAX_MESSAGE_QUEUE_LENGTH = 256;
31
32    private final Queue<Runnable> mJobQueue;
33    private Boolean mIsEnded;
34    private Handler mCameraHandler;
35    private HandlerThread mCameraHandlerThread;
36
37    public DispatchThread(Handler cameraHandler, HandlerThread cameraHandlerThread) {
38        super("Camera Job Dispatch Thread");
39        mJobQueue = new LinkedList<Runnable>();
40        mIsEnded = new Boolean(false);
41        mCameraHandler = cameraHandler;
42        mCameraHandlerThread = cameraHandlerThread;
43    }
44
45    /**
46     * Queues up the job.
47     *
48     * @param job The job to run.
49     */
50    public void runJob(Runnable job) {
51        if (isEnded()) {
52            throw new IllegalStateException(
53                    "Trying to run job on interrupted dispatcher thread");
54        }
55        synchronized (mJobQueue) {
56            if (mJobQueue.size() == MAX_MESSAGE_QUEUE_LENGTH) {
57                throw new RuntimeException("Camera master thread job queue full");
58            }
59
60            mJobQueue.add(job);
61            mJobQueue.notifyAll();
62        }
63    }
64
65    /**
66     * Queues up the job and wait for it to be done.
67     *
68     * @param job The job to run.
69     * @param timeoutMs Timeout limit in milliseconds.
70     * @param jobMsg The message to log when the job runs timeout.
71     * @return Whether the job finishes before timeout.
72     */
73    public void runJobSync(final Runnable job, Object waitLock, long timeoutMs, String jobMsg) {
74        String timeoutMsg = "Timeout waiting " + timeoutMs + "ms for " + jobMsg;
75        synchronized (waitLock) {
76            long timeoutBound = SystemClock.uptimeMillis() + timeoutMs;
77            try {
78                runJob(job);
79                waitLock.wait(timeoutMs);
80                if (SystemClock.uptimeMillis() > timeoutBound) {
81                    throw new IllegalStateException(timeoutMsg);
82                }
83            } catch (InterruptedException ex) {
84                if (SystemClock.uptimeMillis() > timeoutBound) {
85                    throw new IllegalStateException(timeoutMsg);
86                }
87            }
88        }
89    }
90
91    /**
92     * Gracefully ends this thread. Will stop after all jobs are processed.
93     */
94    public void end() {
95        synchronized (mIsEnded) {
96            mIsEnded = true;
97        }
98        synchronized(mJobQueue) {
99            mJobQueue.notifyAll();
100        }
101    }
102
103    private boolean isEnded() {
104        synchronized (mIsEnded) {
105            return mIsEnded;
106        }
107    }
108
109    @Override
110    public void run() {
111        while(true) {
112            Runnable job = null;
113            synchronized (mJobQueue) {
114                while (mJobQueue.size() == 0 && !isEnded()) {
115                    try {
116                        mJobQueue.wait();
117                    } catch (InterruptedException ex) {
118                        Log.w(TAG, "Dispatcher thread wait() interrupted, exiting");
119                        break;
120                    }
121                }
122
123                job = mJobQueue.poll();
124            }
125
126            if (job == null) {
127                // mJobQueue.poll() returning null means wait() is
128                // interrupted and the queue is empty.
129                if (isEnded()) {
130                    break;
131                }
132                continue;
133            }
134
135            job.run();
136
137            synchronized (DispatchThread.this) {
138                mCameraHandler.post(new Runnable() {
139                    @Override
140                    public void run() {
141                        synchronized (DispatchThread.this) {
142                            DispatchThread.this.notifyAll();
143                        }
144                    }
145                });
146                try {
147                    DispatchThread.this.wait();
148                } catch (InterruptedException ex) {
149                    // TODO: do something here.
150                }
151            }
152        }
153        mCameraHandlerThread.quitSafely();
154    }
155}
156