MessageQueue.cpp revision be48137beb68893870c26b7f8c59eac5d0bf517a 
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
63MessageList::value_type MessageQueue::waitMessage(nsecs_t timeout)
64{
65    MessageList::value_type 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                if (timeout>=0 && timeoutTime < now) {
95                    // we timed-out, return a NULL message
96                    result = 0;
97                    break;
98                }
99                nextEventTime = result->when;
100                result = 0;
101            }
102
103            if (timeout >= 0 && nextEventTime > 0) {
104                if (nextEventTime > timeoutTime) {
105                    nextEventTime = timeoutTime;
106                }
107            }
108
109            if (nextEventTime >= 0) {
110                //LOGD("nextEventTime = %lld ms", nextEventTime);
111                if (nextEventTime > 0) {
112                    // we're about to wait, flush the binder command buffer
113                    IPCThreadState::self()->flushCommands();
114                    const nsecs_t reltime = nextEventTime - systemTime();
115                    if (reltime > 0) {
116                        mCondition.waitRelative(mLock, reltime);
117                    }
118                }
119            } else {
120                //LOGD("going to wait");
121                // we're about to wait, flush the binder command buffer
122                IPCThreadState::self()->flushCommands();
123                mCondition.wait(mLock);
124            }
125        }
126        // here we're not holding the lock anymore
127
128        if (result == 0)
129            break;
130
131        again = result->handler();
132        if (again) {
133            // the message has been processed. release our reference to it
134            // without holding the lock.
135            result = 0;
136        }
137
138    } while (again);
139
140    return result;
141}
142
143status_t MessageQueue::postMessage(
144        const MessageList::value_type& message, nsecs_t relTime, uint32_t flags)
145{
146    return queueMessage(message, relTime, flags);
147}
148
149status_t MessageQueue::invalidate() {
150    Mutex::Autolock _l(mLock);
151    mInvalidate = true;
152    mCondition.signal();
153    return NO_ERROR;
154}
155
156status_t MessageQueue::queueMessage(
157        const MessageList::value_type& message, nsecs_t relTime, uint32_t flags)
158{
159    Mutex::Autolock _l(mLock);
160    message->when = systemTime() + relTime;
161    mMessages.insert(message);
162
163    //LOGD("MessageQueue::queueMessage time = %lld ms", message->when);
164    //dumpLocked(message);
165
166    mCondition.signal();
167    return NO_ERROR;
168}
169
170void MessageQueue::dump(const MessageList::value_type& message)
171{
172    Mutex::Autolock _l(mLock);
173    dumpLocked(message);
174}
175
176void MessageQueue::dumpLocked(const MessageList::value_type& message)
177{
178    LIST::const_iterator cur(mMessages.begin());
179    LIST::const_iterator end(mMessages.end());
180    int c = 0;
181    while (cur != end) {
182        const char tick = (*cur == message) ? '>' : ' ';
183        LOGD("%c %d: msg{.what=%08x, when=%lld}",
184                tick, c, (*cur)->what, (*cur)->when);
185        ++cur;
186        c++;
187    }
188}
189
190// ---------------------------------------------------------------------------
191
192}; // namespace android
193