MessageQueue.cpp revision 23a0920339a04c0fcfc3a2840f4e020040c2afbf 
1/*
2 * Copyright (C) 2009 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#include <stdint.h>
18#include <errno.h>
19#include <sys/types.h>
20
21#include <utils/threads.h>
22#include <utils/Timers.h>
23#include <utils/Log.h>
24#include <binder/IPCThreadState.h>
25
26#include "MessageQueue.h"
27
28namespace android {
29
30// ---------------------------------------------------------------------------
31
32void MessageList::insert(const sp<MessageBase>& node)
33{
34    LIST::iterator cur(mList.begin());
35    LIST::iterator end(mList.end());
36    while (cur != end) {
37        if (*node < **cur) {
38            mList.insert(cur, node);
39            return;
40        }
41        ++cur;
42    }
43    mList.insert(++end, node);
44}
45
46void MessageList::remove(MessageList::LIST::iterator pos)
47{
48    mList.erase(pos);
49}
50
51// ---------------------------------------------------------------------------
52
53MessageQueue::MessageQueue()
54    : mInvalidate(false)
55{
56    mInvalidateMessage = new MessageBase(INVALIDATE);
57}
58
59MessageQueue::~MessageQueue()
60{
61}
62
63sp<MessageBase> MessageQueue::waitMessage(nsecs_t timeout)
64{
65    sp<MessageBase> result;
66
67    bool again;
68    do {
69        const nsecs_t timeoutTime = systemTime() + timeout;
70        while (true) {
71            Mutex::Autolock _l(mLock);
72            nsecs_t now = systemTime();
73            nsecs_t nextEventTime = -1;
74
75            // invalidate messages are always handled first
76            if (mInvalidate) {
77                mInvalidate = false;
78                mInvalidateMessage->when = now;
79                result = mInvalidateMessage;
80                break;
81            }
82
83            LIST::iterator cur(mMessages.begin());
84            if (cur != mMessages.end()) {
85                result = *cur;
86            }
87
88            if (result != 0) {
89                if (result->when <= now) {
90                    // there is a message to deliver
91                    mMessages.remove(cur);
92                    break;
93                }
94                nextEventTime = result->when;
95                result = 0;
96            }
97
98            if (timeout >= 0) {
99                if (timeoutTime < now) {
100                    // we timed-out, return a NULL message
101                    result = 0;
102                    break;
103                }
104                if (nextEventTime > 0) {
105                    if (nextEventTime > timeoutTime) {
106                        nextEventTime = timeoutTime;
107                    }
108                } else {
109                    nextEventTime = timeoutTime;
110                }
111            }
112
113            if (nextEventTime >= 0) {
114                //LOGD("nextEventTime = %lld ms", nextEventTime);
115                if (nextEventTime > 0) {
116                    // we're about to wait, flush the binder command buffer
117                    IPCThreadState::self()->flushCommands();
118                    const nsecs_t reltime = nextEventTime - systemTime();
119                    if (reltime > 0) {
120                        mCondition.waitRelative(mLock, reltime);
121                    }
122                }
123            } else {
124                //LOGD("going to wait");
125                // we're about to wait, flush the binder command buffer
126                IPCThreadState::self()->flushCommands();
127                mCondition.wait(mLock);
128            }
129        }
130        // here we're not holding the lock anymore
131
132        if (result == 0)
133            break;
134
135        again = result->handler();
136        if (again) {
137            // the message has been processed. release our reference to it
138            // without holding the lock.
139            result->notify();
140            result = 0;
141        }
142
143    } while (again);
144
145    return result;
146}
147
148status_t MessageQueue::postMessage(
149        const sp<MessageBase>& message, nsecs_t relTime, uint32_t flags)
150{
151    return queueMessage(message, relTime, flags);
152}
153
154status_t MessageQueue::invalidate() {
155    Mutex::Autolock _l(mLock);
156    mInvalidate = true;
157    mCondition.signal();
158    return NO_ERROR;
159}
160
161status_t MessageQueue::queueMessage(
162        const sp<MessageBase>& message, nsecs_t relTime, uint32_t flags)
163{
164    Mutex::Autolock _l(mLock);
165    message->when = systemTime() + relTime;
166    mMessages.insert(message);
167
168    //LOGD("MessageQueue::queueMessage time = %lld ms", message->when);
169    //dumpLocked(message);
170
171    mCondition.signal();
172    return NO_ERROR;
173}
174
175void MessageQueue::dump(const sp<MessageBase>& message)
176{
177    Mutex::Autolock _l(mLock);
178    dumpLocked(message);
179}
180
181void MessageQueue::dumpLocked(const sp<MessageBase>& message)
182{
183    LIST::const_iterator cur(mMessages.begin());
184    LIST::const_iterator end(mMessages.end());
185    int c = 0;
186    while (cur != end) {
187        const char tick = (*cur == message) ? '>' : ' ';
188        LOGD("%c %d: msg{.what=%08x, when=%lld}",
189                tick, c, (*cur)->what, (*cur)->when);
190        ++cur;
191        c++;
192    }
193}
194
195// ---------------------------------------------------------------------------
196
197}; // namespace android
198