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
29 namespace android {
30
31 ALooperRoster gLooperRoster;
32
33 struct ALooper::LooperThread : public Thread {
LooperThreadandroid::ALooper::LooperThread34 LooperThread(ALooper *looper, bool canCallJava)
35 : Thread(canCallJava),
36 mLooper(looper),
37 mThreadId(NULL) {
38 }
39
readyToRunandroid::ALooper::LooperThread40 virtual status_t readyToRun() {
41 mThreadId = androidGetThreadId();
42
43 return Thread::readyToRun();
44 }
45
threadLoopandroid::ALooper::LooperThread46 virtual bool threadLoop() {
47 return mLooper->loop();
48 }
49
isCurrentThreadandroid::ALooper::LooperThread50 bool isCurrentThread() const {
51 return mThreadId == androidGetThreadId();
52 }
53
54 protected:
~LooperThreadandroid::ALooper::LooperThread55 virtual ~LooperThread() {}
56
57 private:
58 ALooper *mLooper;
59 android_thread_id_t mThreadId;
60
61 DISALLOW_EVIL_CONSTRUCTORS(LooperThread);
62 };
63
64 // static
GetNowUs()65 int64_t ALooper::GetNowUs() {
66 return systemTime(SYSTEM_TIME_MONOTONIC) / 1000ll;
67 }
68
ALooper()69 ALooper::ALooper()
70 : mRunningLocally(false) {
71 // clean up stale AHandlers. Doing it here instead of in the destructor avoids
72 // the side effect of objects being deleted from the unregister function recursively.
73 gLooperRoster.unregisterStaleHandlers();
74 }
75
~ALooper()76 ALooper::~ALooper() {
77 stop();
78 // stale AHandlers are now cleaned up in the constructor of the next ALooper to come along
79 }
80
setName(const char * name)81 void ALooper::setName(const char *name) {
82 mName = name;
83 }
84
registerHandler(const sp<AHandler> & handler)85 ALooper::handler_id ALooper::registerHandler(const sp<AHandler> &handler) {
86 return gLooperRoster.registerHandler(this, handler);
87 }
88
unregisterHandler(handler_id handlerID)89 void ALooper::unregisterHandler(handler_id handlerID) {
90 gLooperRoster.unregisterHandler(handlerID);
91 }
92
start(bool runOnCallingThread,bool canCallJava,int32_t priority)93 status_t ALooper::start(
94 bool runOnCallingThread, bool canCallJava, int32_t priority) {
95 if (runOnCallingThread) {
96 {
97 Mutex::Autolock autoLock(mLock);
98
99 if (mThread != NULL || mRunningLocally) {
100 return INVALID_OPERATION;
101 }
102
103 mRunningLocally = true;
104 }
105
106 do {
107 } while (loop());
108
109 return OK;
110 }
111
112 Mutex::Autolock autoLock(mLock);
113
114 if (mThread != NULL || mRunningLocally) {
115 return INVALID_OPERATION;
116 }
117
118 mThread = new LooperThread(this, canCallJava);
119
120 status_t err = mThread->run(
121 mName.empty() ? "ALooper" : mName.c_str(), priority);
122 if (err != OK) {
123 mThread.clear();
124 }
125
126 return err;
127 }
128
stop()129 status_t ALooper::stop() {
130 sp<LooperThread> thread;
131 bool runningLocally;
132
133 {
134 Mutex::Autolock autoLock(mLock);
135
136 thread = mThread;
137 runningLocally = mRunningLocally;
138 mThread.clear();
139 mRunningLocally = false;
140 }
141
142 if (thread == NULL && !runningLocally) {
143 return INVALID_OPERATION;
144 }
145
146 if (thread != NULL) {
147 thread->requestExit();
148 }
149
150 mQueueChangedCondition.signal();
151
152 if (!runningLocally && !thread->isCurrentThread()) {
153 // If not running locally and this thread _is_ the looper thread,
154 // the loop() function will return and never be called again.
155 thread->requestExitAndWait();
156 }
157
158 return OK;
159 }
160
post(const sp<AMessage> & msg,int64_t delayUs)161 void ALooper::post(const sp<AMessage> &msg, int64_t delayUs) {
162 Mutex::Autolock autoLock(mLock);
163
164 int64_t whenUs;
165 if (delayUs > 0) {
166 whenUs = GetNowUs() + delayUs;
167 } else {
168 whenUs = GetNowUs();
169 }
170
171 List<Event>::iterator it = mEventQueue.begin();
172 while (it != mEventQueue.end() && (*it).mWhenUs <= whenUs) {
173 ++it;
174 }
175
176 Event event;
177 event.mWhenUs = whenUs;
178 event.mMessage = msg;
179
180 if (it == mEventQueue.begin()) {
181 mQueueChangedCondition.signal();
182 }
183
184 mEventQueue.insert(it, event);
185 }
186
loop()187 bool ALooper::loop() {
188 Event event;
189
190 {
191 Mutex::Autolock autoLock(mLock);
192 if (mThread == NULL && !mRunningLocally) {
193 return false;
194 }
195 if (mEventQueue.empty()) {
196 mQueueChangedCondition.wait(mLock);
197 return true;
198 }
199 int64_t whenUs = (*mEventQueue.begin()).mWhenUs;
200 int64_t nowUs = GetNowUs();
201
202 if (whenUs > nowUs) {
203 int64_t delayUs = whenUs - nowUs;
204 mQueueChangedCondition.waitRelative(mLock, delayUs * 1000ll);
205
206 return true;
207 }
208
209 event = *mEventQueue.begin();
210 mEventQueue.erase(mEventQueue.begin());
211 }
212
213 gLooperRoster.deliverMessage(event.mMessage);
214
215 // NOTE: It's important to note that at this point our "ALooper" object
216 // may no longer exist (its final reference may have gone away while
217 // delivering the message). We have made sure, however, that loop()
218 // won't be called again.
219
220 return true;
221 }
222
223 } // namespace android
224