diff options
Diffstat (limited to 'libs/utils/PollLoop.cpp')
| -rw-r--r-- | libs/utils/PollLoop.cpp | 377 |
1 files changed, 0 insertions, 377 deletions
diff --git a/libs/utils/PollLoop.cpp b/libs/utils/PollLoop.cpp deleted file mode 100644 index fe76cd0..0000000 --- a/libs/utils/PollLoop.cpp +++ /dev/null @@ -1,377 +0,0 @@ -// -// Copyright 2010 The Android Open Source Project -// -// A select loop implementation. -// -#define LOG_TAG "PollLoop" - -//#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/PollLoop.h> - -#include <unistd.h> -#include <fcntl.h> - -namespace android { - -static pthread_mutex_t gTLSMutex = PTHREAD_MUTEX_INITIALIZER; -static bool gHaveTLS = false; -static pthread_key_t gTLS = 0; - -PollLoop::PollLoop(bool allowNonCallbacks) : - mAllowNonCallbacks(allowNonCallbacks), mPolling(false), - mWaiters(0), mPendingFdsPos(0) { - openWakePipe(); -} - -PollLoop::~PollLoop() { - closeWakePipe(); -} - -void PollLoop::threadDestructor(void *st) { - PollLoop* const self = static_cast<PollLoop*>(st); - if (self != NULL) { - self->decStrong((void*)threadDestructor); - } -} - -void PollLoop::setForThread(const sp<PollLoop>& pollLoop) { - sp<PollLoop> old = getForThread(); - - if (pollLoop != NULL) { - pollLoop->incStrong((void*)threadDestructor); - } - - pthread_setspecific(gTLS, pollLoop.get()); - - if (old != NULL) { - old->decStrong((void*)threadDestructor); - } -} - -sp<PollLoop> PollLoop::getForThread() { - if (!gHaveTLS) { - pthread_mutex_lock(&gTLSMutex); - if (pthread_key_create(&gTLS, threadDestructor) != 0) { - pthread_mutex_unlock(&gTLSMutex); - return NULL; - } - gHaveTLS = true; - pthread_mutex_unlock(&gTLSMutex); - } - - return (PollLoop*)pthread_getspecific(gTLS); -} - -void PollLoop::openWakePipe() { - 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); - - // 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.insertAt(requestedFd, 0); - - RequestedCallback requestedCallback; - requestedCallback.callback = NULL; - requestedCallback.looperCallback = NULL; - requestedCallback.ident = 0; - requestedCallback.data = NULL; - mRequestedCallbacks.insertAt(requestedCallback, 0); -} - -void PollLoop::closeWakePipe() { - close(mWakeReadPipeFd); - close(mWakeWritePipeFd); - - // Note: We don't need to remove the poll structure or callback entry because this - // method is currently only called by the destructor. -} - -int32_t PollLoop::pollOnce(int timeoutMillis, int* outEvents, void** outData) { - // If there are still pending fds from the last call, dispatch those - // first, to avoid an earlier fd from starving later ones. - const size_t pendingFdsCount = mPendingFds.size(); - if (mPendingFdsPos < pendingFdsCount) { - const PendingCallback& pending = mPendingFds.itemAt(mPendingFdsPos); - mPendingFdsPos++; - if (outEvents != NULL) *outEvents = pending.events; - if (outData != NULL) *outData = pending.data; - return pending.ident; - } - - // Wait for wakeAndLock() waiters to run then set mPolling to true. - mLock.lock(); - while (mWaiters != 0) { - mResume.wait(mLock); - } - mPolling = true; - mLock.unlock(); - - // Poll. - int32_t result; - size_t requestedCount = mRequestedFds.size(); - -#if DEBUG_POLL_AND_WAKE - LOGD("%p ~ pollOnce - waiting on %d fds", this, requestedCount); - for (size_t i = 0; i < requestedCount; i++) { - LOGD(" fd %d - events %d", mRequestedFds[i].fd, mRequestedFds[i].events); - } -#endif - - int respondedCount = poll(mRequestedFds.editArray(), requestedCount, timeoutMillis); - - if (respondedCount == 0) { - // Timeout -#if DEBUG_POLL_AND_WAKE - LOGD("%p ~ pollOnce - timeout", this); -#endif - result = POLL_TIMEOUT; - goto Done; - } - - if (respondedCount < 0) { - // Error -#if DEBUG_POLL_AND_WAKE - LOGD("%p ~ pollOnce - error, errno=%d", this, errno); -#endif - if (errno != EINTR) { - LOGW("Poll failed with an unexpected error, errno=%d", errno); - } - result = POLL_ERROR; - goto Done; - } - -#if DEBUG_POLL_AND_WAKE - LOGD("%p ~ pollOnce - handling responses from %d fds", this, respondedCount); - for (size_t i = 0; i < requestedCount; i++) { - LOGD(" fd %d - events %d, revents %d", mRequestedFds[i].fd, mRequestedFds[i].events, - mRequestedFds[i].revents); - } -#endif - - // Process the poll results. - mPendingCallbacks.clear(); - mPendingFds.clear(); - mPendingFdsPos = 0; - if (outEvents != NULL) *outEvents = 0; - if (outData != NULL) *outData = NULL; - - result = POLL_CALLBACK; - for (size_t i = 0; i < requestedCount; i++) { - const struct pollfd& requestedFd = mRequestedFds.itemAt(i); - - short revents = requestedFd.revents; - if (revents) { - const RequestedCallback& requestedCallback = mRequestedCallbacks.itemAt(i); - PendingCallback pending; - pending.fd = requestedFd.fd; - pending.ident = requestedCallback.ident; - pending.events = revents; - pending.callback = requestedCallback.callback; - pending.looperCallback = requestedCallback.looperCallback; - pending.data = requestedCallback.data; - - if (pending.callback || pending.looperCallback) { - mPendingCallbacks.push(pending); - } else if (pending.fd != mWakeReadPipeFd) { - if (result == POLL_CALLBACK) { - result = pending.ident; - if (outEvents != NULL) *outEvents = pending.events; - if (outData != NULL) *outData = pending.data; - } else { - mPendingFds.push(pending); - } - } else { -#if DEBUG_POLL_AND_WAKE - LOGD("%p ~ pollOnce - awoken", this); -#endif - char buffer[16]; - ssize_t nRead; - do { - nRead = read(mWakeReadPipeFd, buffer, sizeof(buffer)); - } while (nRead == sizeof(buffer)); - } - - respondedCount -= 1; - if (respondedCount == 0) { - break; - } - } - } - -Done: - // Set mPolling to false and wake up the wakeAndLock() waiters. - mLock.lock(); - mPolling = false; - if (mWaiters != 0) { - mAwake.broadcast(); - } - mLock.unlock(); - - if (result == POLL_CALLBACK || result >= 0) { - size_t pendingCount = mPendingCallbacks.size(); - for (size_t i = 0; i < pendingCount; i++) { - const PendingCallback& pendingCallback = mPendingCallbacks.itemAt(i); -#if DEBUG_POLL_AND_WAKE || DEBUG_CALLBACKS - LOGD("%p ~ pollOnce - invoking callback for fd %d", this, pendingCallback.fd); -#endif - - bool keep = true; - if (pendingCallback.callback != NULL) { - keep = pendingCallback.callback(pendingCallback.fd, pendingCallback.events, - pendingCallback.data); - } else { - keep = pendingCallback.looperCallback(pendingCallback.fd, pendingCallback.events, - pendingCallback.data) != 0; - } - if (! keep) { - removeCallback(pendingCallback.fd); - } - } - } - -#if DEBUG_POLL_AND_WAKE - LOGD("%p ~ pollOnce - done", this); -#endif - return result; -} - -void PollLoop::wake() { -#if DEBUG_POLL_AND_WAKE - LOGD("%p ~ wake", this); -#endif - - ssize_t nWrite = write(mWakeWritePipeFd, "W", 1); - if (nWrite != 1) { - if (errno != EAGAIN) { - LOGW("Could not write wake signal, errno=%d", errno); - } - } -} - -bool PollLoop::getAllowNonCallbacks() const { - return mAllowNonCallbacks; -} - -void PollLoop::setCallback(int fd, int ident, int events, Callback callback, void* data) { - setCallbackCommon(fd, ident, events, callback, NULL, data); -} - -void PollLoop::setCallback(int fd, int events, Callback callback, void* data) { - setCallbackCommon(fd, POLL_CALLBACK, events, callback, NULL, data); -} - -void PollLoop::setLooperCallback(int fd, int ident, int events, ALooper_callbackFunc* callback, - void* data) { - setCallbackCommon(fd, ident, events, NULL, callback, data); -} - -void PollLoop::setCallbackCommon(int fd, int ident, int events, Callback callback, - ALooper_callbackFunc* looperCallback, void* data) { - -#if DEBUG_CALLBACKS - LOGD("%p ~ setCallback - fd=%d, events=%d", this, fd, events); -#endif - - if (! events) { - LOGE("Invalid attempt to set a callback with no selected poll events."); - removeCallback(fd); - return; - } - - if (! callback && ! looperCallback && ! mAllowNonCallbacks) { - LOGE("Invalid attempt to set NULL callback but not allowed."); - removeCallback(fd); - return; - } - - wakeAndLock(); - - struct pollfd requestedFd; - requestedFd.fd = fd; - requestedFd.events = events; - - RequestedCallback requestedCallback; - requestedCallback.callback = callback; - requestedCallback.looperCallback = looperCallback; - requestedCallback.ident = ident; - requestedCallback.data = data; - - ssize_t index = getRequestIndexLocked(fd); - if (index < 0) { - mRequestedFds.push(requestedFd); - mRequestedCallbacks.push(requestedCallback); - } else { - mRequestedFds.replaceAt(requestedFd, size_t(index)); - mRequestedCallbacks.replaceAt(requestedCallback, size_t(index)); - } - - mLock.unlock(); -} - -bool PollLoop::removeCallback(int fd) { -#if DEBUG_CALLBACKS - LOGD("%p ~ removeCallback - fd=%d", this, fd); -#endif - - wakeAndLock(); - - ssize_t index = getRequestIndexLocked(fd); - if (index >= 0) { - mRequestedFds.removeAt(size_t(index)); - mRequestedCallbacks.removeAt(size_t(index)); - } - - mLock.unlock(); - return index >= 0; -} - -ssize_t PollLoop::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 PollLoop::wakeAndLock() { - mLock.lock(); - - mWaiters += 1; - while (mPolling) { - wake(); - mAwake.wait(mLock); - } - - mWaiters -= 1; - if (mWaiters == 0) { - mResume.signal(); - } -} - -} // namespace android |