ALooper.cpp revision 42d7f83904b8a91ce33e87a44de109572679ac1f 
1/*
2 * Copyright (C) 2010 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//#define LOG_NDEBUG 0
18#define LOG_TAG "ALooper"
19#include <utils/Log.h>
20
21#include <sys/time.h>
22
23#include "ALooper.h"
24
25#include "AHandler.h"
26#include "ALooperRoster.h"
27#include "AMessage.h"
28
29namespace android {
30
31ALooperRoster gLooperRoster;
32
33struct ALooper::LooperThread : public Thread {
34    LooperThread(ALooper *looper, bool canCallJava)
35        : Thread(canCallJava),
36          mLooper(looper) {
37    }
38
39    virtual bool threadLoop() {
40        return mLooper->loop();
41    }
42
43protected:
44    virtual ~LooperThread() {}
45
46private:
47    ALooper *mLooper;
48
49    DISALLOW_EVIL_CONSTRUCTORS(LooperThread);
50};
51
52// static
53int64_t ALooper::GetNowUs() {
54    struct timeval tv;
55    gettimeofday(&tv, NULL);
56
57    return (int64_t)tv.tv_sec * 1000000ll + tv.tv_usec;
58}
59
60ALooper::ALooper()
61    : mRunningLocally(false) {
62}
63
64ALooper::~ALooper() {
65    stop();
66}
67
68ALooper::handler_id ALooper::registerHandler(const sp<AHandler> &handler) {
69    return gLooperRoster.registerHandler(this, handler);
70}
71
72void ALooper::unregisterHandler(handler_id handlerID) {
73    gLooperRoster.unregisterHandler(handlerID);
74}
75
76status_t ALooper::start(bool runOnCallingThread, bool canCallJava) {
77    if (runOnCallingThread) {
78        {
79            Mutex::Autolock autoLock(mLock);
80
81            if (mThread != NULL || mRunningLocally) {
82                return INVALID_OPERATION;
83            }
84
85            mRunningLocally = true;
86        }
87
88        do {
89        } while (loop());
90
91        return OK;
92    }
93
94    Mutex::Autolock autoLock(mLock);
95
96    if (mThread != NULL || mRunningLocally) {
97        return INVALID_OPERATION;
98    }
99
100    mThread = new LooperThread(this, canCallJava);
101
102    status_t err = mThread->run("ALooper");
103    if (err != OK) {
104        mThread.clear();
105    }
106
107    return err;
108}
109
110status_t ALooper::stop() {
111    sp<LooperThread> thread;
112    bool runningLocally;
113
114    {
115        Mutex::Autolock autoLock(mLock);
116
117        thread = mThread;
118        runningLocally = mRunningLocally;
119        mThread.clear();
120        mRunningLocally = false;
121    }
122
123    if (thread == NULL && !runningLocally) {
124        return INVALID_OPERATION;
125    }
126
127    if (thread != NULL) {
128        thread->requestExit();
129    }
130
131    mQueueChangedCondition.signal();
132
133    if (!runningLocally) {
134        thread->requestExitAndWait();
135    }
136
137    return OK;
138}
139
140void ALooper::post(const sp<AMessage> &msg, int64_t delayUs) {
141    Mutex::Autolock autoLock(mLock);
142
143    int64_t whenUs;
144    if (delayUs > 0) {
145        whenUs = GetNowUs() + delayUs;
146    } else {
147        whenUs = GetNowUs();
148    }
149
150    List<Event>::iterator it = mEventQueue.begin();
151    while (it != mEventQueue.end() && (*it).mWhenUs <= whenUs) {
152        ++it;
153    }
154
155    Event event;
156    event.mWhenUs = whenUs;
157    event.mMessage = msg;
158
159    if (it == mEventQueue.begin()) {
160        mQueueChangedCondition.signal();
161    }
162
163    mEventQueue.insert(it, event);
164}
165
166bool ALooper::loop() {
167    Event event;
168
169    {
170        Mutex::Autolock autoLock(mLock);
171        if (mThread == NULL && !mRunningLocally) {
172            return false;
173        }
174        if (mEventQueue.empty()) {
175            mQueueChangedCondition.wait(mLock);
176            return true;
177        }
178        int64_t whenUs = (*mEventQueue.begin()).mWhenUs;
179        int64_t nowUs = GetNowUs();
180
181        if (whenUs > nowUs) {
182            int64_t delayUs = whenUs - nowUs;
183            mQueueChangedCondition.waitRelative(mLock, delayUs * 1000ll);
184
185            return true;
186        }
187
188        event = *mEventQueue.begin();
189        mEventQueue.erase(mEventQueue.begin());
190    }
191
192    gLooperRoster.deliverMessage(event.mMessage);
193
194    return true;
195}
196
197}  // namespace android
198