replicant-frameworks_native/libs/utils/Looper.cpp
Jeff Brown 4815f2a6ad Initial checkin of spot presentation for touchpad gestures.
Added a new PointerIcon API (hidden for now) for loading
pointer icons.

Fixed a starvation problem in the native Looper's sendMessage
implementation which caused new messages to be posted ahead
of old messages sent with sendMessageDelayed.

Redesigned the touch pad gestures to be defined in terms of
more fluid finger / spot movements.  The objective is to reinforce
the natural mapping between fingers and spots which means there
must not be any discontinuities in spot motion relative to
the fingers.

Removed the SpotController stub and folded its responsibilities
into PointerController.

Change-Id: I5126b1e69d95252fda7f2a684c9287e239a57163
2011-04-19 15:35:51 -07:00

745 lines
23 KiB
C++

//
// Copyright 2010 The Android Open Source Project
//
// A looper implementation based on epoll().
//
#define LOG_TAG "Looper"
//#define LOG_NDEBUG 0
// Debugs poll and wake interactions.
#define DEBUG_POLL_AND_WAKE 0
// Debugs callback registration and invocation.
#define DEBUG_CALLBACKS 0
#include <cutils/log.h>
#include <utils/Looper.h>
#include <utils/Timers.h>
#include <unistd.h>
#include <fcntl.h>
#include <limits.h>
namespace android {
// --- WeakMessageHandler ---
WeakMessageHandler::WeakMessageHandler(const wp<MessageHandler>& handler) :
mHandler(handler) {
}
void WeakMessageHandler::handleMessage(const Message& message) {
sp<MessageHandler> handler = mHandler.promote();
if (handler != NULL) {
handler->handleMessage(message);
}
}
// --- Looper ---
#ifdef LOOPER_USES_EPOLL
// Hint for number of file descriptors to be associated with the epoll instance.
static const int EPOLL_SIZE_HINT = 8;
// Maximum number of file descriptors for which to retrieve poll events each iteration.
static const int EPOLL_MAX_EVENTS = 16;
#endif
static pthread_once_t gTLSOnce = PTHREAD_ONCE_INIT;
static pthread_key_t gTLSKey = 0;
Looper::Looper(bool allowNonCallbacks) :
mAllowNonCallbacks(allowNonCallbacks), mSendingMessage(false),
mResponseIndex(0), mNextMessageUptime(LLONG_MAX) {
int wakeFds[2];
int result = pipe(wakeFds);
LOG_ALWAYS_FATAL_IF(result != 0, "Could not create wake pipe. errno=%d", errno);
mWakeReadPipeFd = wakeFds[0];
mWakeWritePipeFd = wakeFds[1];
result = fcntl(mWakeReadPipeFd, F_SETFL, O_NONBLOCK);
LOG_ALWAYS_FATAL_IF(result != 0, "Could not make wake read pipe non-blocking. errno=%d",
errno);
result = fcntl(mWakeWritePipeFd, F_SETFL, O_NONBLOCK);
LOG_ALWAYS_FATAL_IF(result != 0, "Could not make wake write pipe non-blocking. errno=%d",
errno);
#ifdef LOOPER_USES_EPOLL
// Allocate the epoll instance and register the wake pipe.
mEpollFd = epoll_create(EPOLL_SIZE_HINT);
LOG_ALWAYS_FATAL_IF(mEpollFd < 0, "Could not create epoll instance. errno=%d", errno);
struct epoll_event eventItem;
memset(& eventItem, 0, sizeof(epoll_event)); // zero out unused members of data field union
eventItem.events = EPOLLIN;
eventItem.data.fd = mWakeReadPipeFd;
result = epoll_ctl(mEpollFd, EPOLL_CTL_ADD, mWakeReadPipeFd, & eventItem);
LOG_ALWAYS_FATAL_IF(result != 0, "Could not add wake read pipe to epoll instance. errno=%d",
errno);
#else
// Add the wake pipe to the head of the request list with a null callback.
struct pollfd requestedFd;
requestedFd.fd = mWakeReadPipeFd;
requestedFd.events = POLLIN;
mRequestedFds.push(requestedFd);
Request request;
request.fd = mWakeReadPipeFd;
request.callback = NULL;
request.ident = 0;
request.data = NULL;
mRequests.push(request);
mPolling = false;
mWaiters = 0;
#endif
#ifdef LOOPER_STATISTICS
mPendingWakeTime = -1;
mPendingWakeCount = 0;
mSampledWakeCycles = 0;
mSampledWakeCountSum = 0;
mSampledWakeLatencySum = 0;
mSampledPolls = 0;
mSampledZeroPollCount = 0;
mSampledZeroPollLatencySum = 0;
mSampledTimeoutPollCount = 0;
mSampledTimeoutPollLatencySum = 0;
#endif
}
Looper::~Looper() {
close(mWakeReadPipeFd);
close(mWakeWritePipeFd);
#ifdef LOOPER_USES_EPOLL
close(mEpollFd);
#endif
}
void Looper::initTLSKey() {
int result = pthread_key_create(& gTLSKey, threadDestructor);
LOG_ALWAYS_FATAL_IF(result != 0, "Could not allocate TLS key.");
}
void Looper::threadDestructor(void *st) {
Looper* const self = static_cast<Looper*>(st);
if (self != NULL) {
self->decStrong((void*)threadDestructor);
}
}
void Looper::setForThread(const sp<Looper>& looper) {
sp<Looper> old = getForThread(); // also has side-effect of initializing TLS
if (looper != NULL) {
looper->incStrong((void*)threadDestructor);
}
pthread_setspecific(gTLSKey, looper.get());
if (old != NULL) {
old->decStrong((void*)threadDestructor);
}
}
sp<Looper> Looper::getForThread() {
int result = pthread_once(& gTLSOnce, initTLSKey);
LOG_ALWAYS_FATAL_IF(result != 0, "pthread_once failed");
return (Looper*)pthread_getspecific(gTLSKey);
}
sp<Looper> Looper::prepare(int opts) {
bool allowNonCallbacks = opts & ALOOPER_PREPARE_ALLOW_NON_CALLBACKS;
sp<Looper> looper = Looper::getForThread();
if (looper == NULL) {
looper = new Looper(allowNonCallbacks);
Looper::setForThread(looper);
}
if (looper->getAllowNonCallbacks() != allowNonCallbacks) {
LOGW("Looper already prepared for this thread with a different value for the "
"ALOOPER_PREPARE_ALLOW_NON_CALLBACKS option.");
}
return looper;
}
bool Looper::getAllowNonCallbacks() const {
return mAllowNonCallbacks;
}
int Looper::pollOnce(int timeoutMillis, int* outFd, int* outEvents, void** outData) {
int result = 0;
for (;;) {
while (mResponseIndex < mResponses.size()) {
const Response& response = mResponses.itemAt(mResponseIndex++);
ALooper_callbackFunc callback = response.request.callback;
if (!callback) {
int ident = response.request.ident;
int fd = response.request.fd;
int events = response.events;
void* data = response.request.data;
#if DEBUG_POLL_AND_WAKE
LOGD("%p ~ pollOnce - returning signalled identifier %d: "
"fd=%d, events=0x%x, data=%p",
this, ident, fd, events, data);
#endif
if (outFd != NULL) *outFd = fd;
if (outEvents != NULL) *outEvents = events;
if (outData != NULL) *outData = data;
return ident;
}
}
if (result != 0) {
#if DEBUG_POLL_AND_WAKE
LOGD("%p ~ pollOnce - returning result %d", this, result);
#endif
if (outFd != NULL) *outFd = 0;
if (outEvents != NULL) *outEvents = NULL;
if (outData != NULL) *outData = NULL;
return result;
}
result = pollInner(timeoutMillis);
}
}
int Looper::pollInner(int timeoutMillis) {
#if DEBUG_POLL_AND_WAKE
LOGD("%p ~ pollOnce - waiting: timeoutMillis=%d", this, timeoutMillis);
#endif
// Adjust the timeout based on when the next message is due.
if (timeoutMillis != 0 && mNextMessageUptime != LLONG_MAX) {
nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
int messageTimeoutMillis = toMillisecondTimeoutDelay(now, mNextMessageUptime);
if (messageTimeoutMillis >= 0
&& (timeoutMillis < 0 || messageTimeoutMillis < timeoutMillis)) {
timeoutMillis = messageTimeoutMillis;
}
#if DEBUG_POLL_AND_WAKE
LOGD("%p ~ pollOnce - next message in %lldns, adjusted timeout: timeoutMillis=%d",
this, mNextMessageUptime - now, timeoutMillis);
#endif
}
// Poll.
int result = ALOOPER_POLL_WAKE;
mResponses.clear();
mResponseIndex = 0;
#ifdef LOOPER_STATISTICS
nsecs_t pollStartTime = systemTime(SYSTEM_TIME_MONOTONIC);
#endif
#ifdef LOOPER_USES_EPOLL
struct epoll_event eventItems[EPOLL_MAX_EVENTS];
int eventCount = epoll_wait(mEpollFd, eventItems, EPOLL_MAX_EVENTS, timeoutMillis);
#else
// Wait for wakeAndLock() waiters to run then set mPolling to true.
mLock.lock();
while (mWaiters != 0) {
mResume.wait(mLock);
}
mPolling = true;
mLock.unlock();
size_t requestedCount = mRequestedFds.size();
int eventCount = poll(mRequestedFds.editArray(), requestedCount, timeoutMillis);
#endif
// Acquire lock.
mLock.lock();
// Check for poll error.
if (eventCount < 0) {
if (errno == EINTR) {
goto Done;
}
LOGW("Poll failed with an unexpected error, errno=%d", errno);
result = ALOOPER_POLL_ERROR;
goto Done;
}
// Check for poll timeout.
if (eventCount == 0) {
#if DEBUG_POLL_AND_WAKE
LOGD("%p ~ pollOnce - timeout", this);
#endif
result = ALOOPER_POLL_TIMEOUT;
goto Done;
}
// Handle all events.
#if DEBUG_POLL_AND_WAKE
LOGD("%p ~ pollOnce - handling events from %d fds", this, eventCount);
#endif
#ifdef LOOPER_USES_EPOLL
for (int i = 0; i < eventCount; i++) {
int fd = eventItems[i].data.fd;
uint32_t epollEvents = eventItems[i].events;
if (fd == mWakeReadPipeFd) {
if (epollEvents & EPOLLIN) {
awoken();
} else {
LOGW("Ignoring unexpected epoll events 0x%x on wake read pipe.", epollEvents);
}
} else {
ssize_t requestIndex = mRequests.indexOfKey(fd);
if (requestIndex >= 0) {
int events = 0;
if (epollEvents & EPOLLIN) events |= ALOOPER_EVENT_INPUT;
if (epollEvents & EPOLLOUT) events |= ALOOPER_EVENT_OUTPUT;
if (epollEvents & EPOLLERR) events |= ALOOPER_EVENT_ERROR;
if (epollEvents & EPOLLHUP) events |= ALOOPER_EVENT_HANGUP;
pushResponse(events, mRequests.valueAt(requestIndex));
} else {
LOGW("Ignoring unexpected epoll events 0x%x on fd %d that is "
"no longer registered.", epollEvents, fd);
}
}
}
Done: ;
#else
for (size_t i = 0; i < requestedCount; i++) {
const struct pollfd& requestedFd = mRequestedFds.itemAt(i);
short pollEvents = requestedFd.revents;
if (pollEvents) {
if (requestedFd.fd == mWakeReadPipeFd) {
if (pollEvents & POLLIN) {
awoken();
} else {
LOGW("Ignoring unexpected poll events 0x%x on wake read pipe.", pollEvents);
}
} else {
int events = 0;
if (pollEvents & POLLIN) events |= ALOOPER_EVENT_INPUT;
if (pollEvents & POLLOUT) events |= ALOOPER_EVENT_OUTPUT;
if (pollEvents & POLLERR) events |= ALOOPER_EVENT_ERROR;
if (pollEvents & POLLHUP) events |= ALOOPER_EVENT_HANGUP;
if (pollEvents & POLLNVAL) events |= ALOOPER_EVENT_INVALID;
pushResponse(events, mRequests.itemAt(i));
}
if (--eventCount == 0) {
break;
}
}
}
Done:
// Set mPolling to false and wake up the wakeAndLock() waiters.
mPolling = false;
if (mWaiters != 0) {
mAwake.broadcast();
}
#endif
#ifdef LOOPER_STATISTICS
nsecs_t pollEndTime = systemTime(SYSTEM_TIME_MONOTONIC);
mSampledPolls += 1;
if (timeoutMillis == 0) {
mSampledZeroPollCount += 1;
mSampledZeroPollLatencySum += pollEndTime - pollStartTime;
} else if (timeoutMillis > 0 && result == ALOOPER_POLL_TIMEOUT) {
mSampledTimeoutPollCount += 1;
mSampledTimeoutPollLatencySum += pollEndTime - pollStartTime
- milliseconds_to_nanoseconds(timeoutMillis);
}
if (mSampledPolls == SAMPLED_POLLS_TO_AGGREGATE) {
LOGD("%p ~ poll latency statistics: %0.3fms zero timeout, %0.3fms non-zero timeout", this,
0.000001f * float(mSampledZeroPollLatencySum) / mSampledZeroPollCount,
0.000001f * float(mSampledTimeoutPollLatencySum) / mSampledTimeoutPollCount);
mSampledPolls = 0;
mSampledZeroPollCount = 0;
mSampledZeroPollLatencySum = 0;
mSampledTimeoutPollCount = 0;
mSampledTimeoutPollLatencySum = 0;
}
#endif
// Invoke pending message callbacks.
mNextMessageUptime = LLONG_MAX;
while (mMessageEnvelopes.size() != 0) {
nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
const MessageEnvelope& messageEnvelope = mMessageEnvelopes.itemAt(0);
if (messageEnvelope.uptime <= now) {
// Remove the envelope from the list.
// We keep a strong reference to the handler until the call to handleMessage
// finishes. Then we drop it so that the handler can be deleted *before*
// we reacquire our lock.
{ // obtain handler
sp<MessageHandler> handler = messageEnvelope.handler;
Message message = messageEnvelope.message;
mMessageEnvelopes.removeAt(0);
mSendingMessage = true;
mLock.unlock();
#if DEBUG_POLL_AND_WAKE || DEBUG_CALLBACKS
LOGD("%p ~ pollOnce - sending message: handler=%p, what=%d",
this, handler.get(), message.what);
#endif
handler->handleMessage(message);
} // release handler
mLock.lock();
mSendingMessage = false;
result = ALOOPER_POLL_CALLBACK;
} else {
// The last message left at the head of the queue determines the next wakeup time.
mNextMessageUptime = messageEnvelope.uptime;
break;
}
}
// Release lock.
mLock.unlock();
// Invoke all response callbacks.
for (size_t i = 0; i < mResponses.size(); i++) {
const Response& response = mResponses.itemAt(i);
ALooper_callbackFunc callback = response.request.callback;
if (callback) {
int fd = response.request.fd;
int events = response.events;
void* data = response.request.data;
#if DEBUG_POLL_AND_WAKE || DEBUG_CALLBACKS
LOGD("%p ~ pollOnce - invoking fd event callback %p: fd=%d, events=0x%x, data=%p",
this, callback, fd, events, data);
#endif
int callbackResult = callback(fd, events, data);
if (callbackResult == 0) {
removeFd(fd);
}
result = ALOOPER_POLL_CALLBACK;
}
}
return result;
}
int Looper::pollAll(int timeoutMillis, int* outFd, int* outEvents, void** outData) {
if (timeoutMillis <= 0) {
int result;
do {
result = pollOnce(timeoutMillis, outFd, outEvents, outData);
} while (result == ALOOPER_POLL_CALLBACK);
return result;
} else {
nsecs_t endTime = systemTime(SYSTEM_TIME_MONOTONIC)
+ milliseconds_to_nanoseconds(timeoutMillis);
for (;;) {
int result = pollOnce(timeoutMillis, outFd, outEvents, outData);
if (result != ALOOPER_POLL_CALLBACK) {
return result;
}
nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
timeoutMillis = toMillisecondTimeoutDelay(now, endTime);
if (timeoutMillis == 0) {
return ALOOPER_POLL_TIMEOUT;
}
}
}
}
void Looper::wake() {
#if DEBUG_POLL_AND_WAKE
LOGD("%p ~ wake", this);
#endif
#ifdef LOOPER_STATISTICS
// FIXME: Possible race with awoken() but this code is for testing only and is rarely enabled.
if (mPendingWakeCount++ == 0) {
mPendingWakeTime = systemTime(SYSTEM_TIME_MONOTONIC);
}
#endif
ssize_t nWrite;
do {
nWrite = write(mWakeWritePipeFd, "W", 1);
} while (nWrite == -1 && errno == EINTR);
if (nWrite != 1) {
if (errno != EAGAIN) {
LOGW("Could not write wake signal, errno=%d", errno);
}
}
}
void Looper::awoken() {
#if DEBUG_POLL_AND_WAKE
LOGD("%p ~ awoken", this);
#endif
#ifdef LOOPER_STATISTICS
if (mPendingWakeCount == 0) {
LOGD("%p ~ awoken: spurious!", this);
} else {
mSampledWakeCycles += 1;
mSampledWakeCountSum += mPendingWakeCount;
mSampledWakeLatencySum += systemTime(SYSTEM_TIME_MONOTONIC) - mPendingWakeTime;
mPendingWakeCount = 0;
mPendingWakeTime = -1;
if (mSampledWakeCycles == SAMPLED_WAKE_CYCLES_TO_AGGREGATE) {
LOGD("%p ~ wake statistics: %0.3fms wake latency, %0.3f wakes per cycle", this,
0.000001f * float(mSampledWakeLatencySum) / mSampledWakeCycles,
float(mSampledWakeCountSum) / mSampledWakeCycles);
mSampledWakeCycles = 0;
mSampledWakeCountSum = 0;
mSampledWakeLatencySum = 0;
}
}
#endif
char buffer[16];
ssize_t nRead;
do {
nRead = read(mWakeReadPipeFd, buffer, sizeof(buffer));
} while ((nRead == -1 && errno == EINTR) || nRead == sizeof(buffer));
}
void Looper::pushResponse(int events, const Request& request) {
Response response;
response.events = events;
response.request = request;
mResponses.push(response);
}
int Looper::addFd(int fd, int ident, int events, ALooper_callbackFunc callback, void* data) {
#if DEBUG_CALLBACKS
LOGD("%p ~ addFd - fd=%d, ident=%d, events=0x%x, callback=%p, data=%p", this, fd, ident,
events, callback, data);
#endif
if (! callback) {
if (! mAllowNonCallbacks) {
LOGE("Invalid attempt to set NULL callback but not allowed for this looper.");
return -1;
}
if (ident < 0) {
LOGE("Invalid attempt to set NULL callback with ident <= 0.");
return -1;
}
}
#ifdef LOOPER_USES_EPOLL
int epollEvents = 0;
if (events & ALOOPER_EVENT_INPUT) epollEvents |= EPOLLIN;
if (events & ALOOPER_EVENT_OUTPUT) epollEvents |= EPOLLOUT;
{ // acquire lock
AutoMutex _l(mLock);
Request request;
request.fd = fd;
request.ident = ident;
request.callback = callback;
request.data = data;
struct epoll_event eventItem;
memset(& eventItem, 0, sizeof(epoll_event)); // zero out unused members of data field union
eventItem.events = epollEvents;
eventItem.data.fd = fd;
ssize_t requestIndex = mRequests.indexOfKey(fd);
if (requestIndex < 0) {
int epollResult = epoll_ctl(mEpollFd, EPOLL_CTL_ADD, fd, & eventItem);
if (epollResult < 0) {
LOGE("Error adding epoll events for fd %d, errno=%d", fd, errno);
return -1;
}
mRequests.add(fd, request);
} else {
int epollResult = epoll_ctl(mEpollFd, EPOLL_CTL_MOD, fd, & eventItem);
if (epollResult < 0) {
LOGE("Error modifying epoll events for fd %d, errno=%d", fd, errno);
return -1;
}
mRequests.replaceValueAt(requestIndex, request);
}
} // release lock
#else
int pollEvents = 0;
if (events & ALOOPER_EVENT_INPUT) pollEvents |= POLLIN;
if (events & ALOOPER_EVENT_OUTPUT) pollEvents |= POLLOUT;
wakeAndLock(); // acquire lock
struct pollfd requestedFd;
requestedFd.fd = fd;
requestedFd.events = pollEvents;
Request request;
request.fd = fd;
request.ident = ident;
request.callback = callback;
request.data = data;
ssize_t index = getRequestIndexLocked(fd);
if (index < 0) {
mRequestedFds.push(requestedFd);
mRequests.push(request);
} else {
mRequestedFds.replaceAt(requestedFd, size_t(index));
mRequests.replaceAt(request, size_t(index));
}
mLock.unlock(); // release lock
#endif
return 1;
}
int Looper::removeFd(int fd) {
#if DEBUG_CALLBACKS
LOGD("%p ~ removeFd - fd=%d", this, fd);
#endif
#ifdef LOOPER_USES_EPOLL
{ // acquire lock
AutoMutex _l(mLock);
ssize_t requestIndex = mRequests.indexOfKey(fd);
if (requestIndex < 0) {
return 0;
}
int epollResult = epoll_ctl(mEpollFd, EPOLL_CTL_DEL, fd, NULL);
if (epollResult < 0) {
LOGE("Error removing epoll events for fd %d, errno=%d", fd, errno);
return -1;
}
mRequests.removeItemsAt(requestIndex);
} // release lock
return 1;
#else
wakeAndLock(); // acquire lock
ssize_t index = getRequestIndexLocked(fd);
if (index >= 0) {
mRequestedFds.removeAt(size_t(index));
mRequests.removeAt(size_t(index));
}
mLock.unlock(); // release lock
return index >= 0;
#endif
}
#ifndef LOOPER_USES_EPOLL
ssize_t Looper::getRequestIndexLocked(int fd) {
size_t requestCount = mRequestedFds.size();
for (size_t i = 0; i < requestCount; i++) {
if (mRequestedFds.itemAt(i).fd == fd) {
return i;
}
}
return -1;
}
void Looper::wakeAndLock() {
mLock.lock();
mWaiters += 1;
while (mPolling) {
wake();
mAwake.wait(mLock);
}
mWaiters -= 1;
if (mWaiters == 0) {
mResume.signal();
}
}
#endif
void Looper::sendMessage(const sp<MessageHandler>& handler, const Message& message) {
nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
sendMessageAtTime(now, handler, message);
}
void Looper::sendMessageDelayed(nsecs_t uptimeDelay, const sp<MessageHandler>& handler,
const Message& message) {
nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
sendMessageAtTime(now + uptimeDelay, handler, message);
}
void Looper::sendMessageAtTime(nsecs_t uptime, const sp<MessageHandler>& handler,
const Message& message) {
#if DEBUG_CALLBACKS
LOGD("%p ~ sendMessageAtTime - uptime=%lld, handler=%p, what=%d",
this, uptime, handler.get(), message.what);
#endif
size_t i = 0;
{ // acquire lock
AutoMutex _l(mLock);
size_t messageCount = mMessageEnvelopes.size();
while (i < messageCount && uptime >= mMessageEnvelopes.itemAt(i).uptime) {
i += 1;
}
MessageEnvelope messageEnvelope(uptime, handler, message);
mMessageEnvelopes.insertAt(messageEnvelope, i, 1);
// Optimization: If the Looper is currently sending a message, then we can skip
// the call to wake() because the next thing the Looper will do after processing
// messages is to decide when the next wakeup time should be. In fact, it does
// not even matter whether this code is running on the Looper thread.
if (mSendingMessage) {
return;
}
} // release lock
// Wake the poll loop only when we enqueue a new message at the head.
if (i == 0) {
wake();
}
}
void Looper::removeMessages(const sp<MessageHandler>& handler) {
#if DEBUG_CALLBACKS
LOGD("%p ~ removeMessages - handler=%p", this, handler.get());
#endif
{ // acquire lock
AutoMutex _l(mLock);
for (size_t i = mMessageEnvelopes.size(); i != 0; ) {
const MessageEnvelope& messageEnvelope = mMessageEnvelopes.itemAt(--i);
if (messageEnvelope.handler == handler) {
mMessageEnvelopes.removeAt(i);
}
}
} // release lock
}
void Looper::removeMessages(const sp<MessageHandler>& handler, int what) {
#if DEBUG_CALLBACKS
LOGD("%p ~ removeMessages - handler=%p, what=%d", this, handler.get(), what);
#endif
{ // acquire lock
AutoMutex _l(mLock);
for (size_t i = mMessageEnvelopes.size(); i != 0; ) {
const MessageEnvelope& messageEnvelope = mMessageEnvelopes.itemAt(--i);
if (messageEnvelope.handler == handler
&& messageEnvelope.message.what == what) {
mMessageEnvelopes.removeAt(i);
}
}
} // release lock
}
} // namespace android