| // Copyright 2010-2015, Google Inc. |
| // All rights reserved. |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following disclaimer |
| // in the documentation and/or other materials provided with the |
| // distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived from |
| // this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| #include "base/unnamed_event.h" |
| |
| #ifdef OS_WIN |
| #include <windows.h> |
| #else // OS_WIN |
| #include <errno.h> |
| #include <pthread.h> |
| #include <sys/time.h> |
| #endif // OS_WIN |
| |
| #include "base/logging.h" |
| #include "base/port.h" |
| |
| namespace mozc { |
| |
| #ifdef OS_WIN |
| UnnamedEvent::UnnamedEvent() |
| : handle_(::CreateEvent(NULL, FALSE, FALSE, NULL)) { |
| // Use Auto reset mode of Win32 Event. (2nd arg of CreateEvent). |
| // pthread_cond_signal: auto reset mode. |
| // pthread_cond_broadcast: manual reset mode. |
| if (NULL == handle_.get()) { |
| LOG(ERROR) << "CreateEvent failed: " << ::GetLastError(); |
| } |
| } |
| |
| UnnamedEvent::~UnnamedEvent() {} |
| |
| bool UnnamedEvent::IsAvailable() const { |
| return (NULL != handle_.get()); |
| } |
| |
| bool UnnamedEvent::Notify() { |
| if (!IsAvailable()) { |
| LOG(WARNING) << "Event object is not available"; |
| return false; |
| } |
| |
| if (!::SetEvent(handle_.get())) { |
| LOG(ERROR) << "SetEvent failed: " << ::GetLastError(); |
| return false; |
| } |
| |
| return true; |
| } |
| |
| bool UnnamedEvent::Wait(int msec) { |
| if (!IsAvailable()) { |
| return true; // assume that it is already raised |
| } |
| |
| if (msec < 0) { |
| msec = INFINITE; |
| } |
| |
| return WAIT_TIMEOUT != |
| ::WaitForSingleObject(handle_.get(), msec); |
| } |
| |
| #else // OS_WIN |
| |
| namespace { |
| class ScopedPthreadMutexLock { |
| public: |
| explicit ScopedPthreadMutexLock(pthread_mutex_t *mutex) : mutex_(mutex) { |
| pthread_mutex_lock(mutex_); |
| } |
| ~ScopedPthreadMutexLock() { |
| pthread_mutex_unlock(mutex_); |
| } |
| |
| private: |
| pthread_mutex_t *mutex_; |
| DISALLOW_COPY_AND_ASSIGN(ScopedPthreadMutexLock); |
| }; |
| } // namespace |
| |
| UnnamedEvent::UnnamedEvent() : notified_(false) { |
| pthread_mutex_init(&mutex_, NULL); |
| pthread_cond_init(&cond_, NULL); |
| } |
| |
| // It is necessary to ensure that no threads wait for this event before the |
| // destruction. |
| UnnamedEvent::~UnnamedEvent() { |
| pthread_mutex_destroy(&mutex_); |
| pthread_cond_destroy(&cond_); |
| } |
| |
| bool UnnamedEvent::IsAvailable() const { |
| return true; |
| } |
| |
| bool UnnamedEvent::Notify() { |
| { |
| ScopedPthreadMutexLock lock(&mutex_); |
| notified_ = true; |
| } |
| |
| // Note: Need to awake all threads waiting for this event. Otherwise |
| // some thread would start to work incorrectly in some cases. |
| // An example error scenario is: |
| // - there are four threads, A, B, C and D. |
| // - A and B are producers. C and D are consumers. |
| // - C and D start to wait this event. |
| // - Then A notifies. |
| // - A takes the lock. |
| // - set notified_ true. |
| // - A releases the lock. |
| // - Then before A sends a signal to awake a thread (either C or D), |
| // B takes the lock. |
| // - A sends a signal, but both C and D are sleeping as the lock is |
| // still taken by B. |
| // - B releases the lock. So one of the thread (let's assume C for this |
| // example) starts to run, because it can take the lock. |
| // - B also sends a signal again. |
| // - C overrides notified_ to false, and releases the lock. |
| // - At last, D starts to run wrongly. |
| // The broadcast and while (in Wait) idiom is a popular way to fix such |
| // cases. |
| pthread_cond_broadcast(&cond_); |
| return true; |
| } |
| |
| bool UnnamedEvent::Wait(int msec) { |
| ScopedPthreadMutexLock lock(&mutex_); |
| if (!notified_) { |
| // Need to wait actually. |
| if (msec < 0) { |
| // Wait forever. |
| while (!notified_) { |
| pthread_cond_wait(&cond_, &mutex_); |
| } |
| } else { |
| // Wait with time out. |
| struct timeval tv; |
| if (gettimeofday(&tv, NULL) != 0) { |
| LOG(ERROR) << "Failed to take the current time: " << errno; |
| return false; |
| } |
| |
| struct timespec timeout; |
| timeout.tv_sec = tv.tv_sec + msec / 1000; |
| timeout.tv_nsec = 1000 * (tv.tv_usec + 1000 * (msec % 1000)); |
| |
| // if tv_nsec >= 10^9, pthread_cond_timedwait may return EINVAL |
| while (timeout.tv_nsec >= 1000000000) { |
| timeout.tv_sec++; |
| timeout.tv_nsec -= 1000000000; |
| } |
| |
| int result = 0; |
| while (!notified_ && result == 0) { |
| result = pthread_cond_timedwait(&cond_, &mutex_, &timeout); |
| } |
| |
| if (result != 0) { |
| // Time out. |
| return false; |
| } |
| } |
| } |
| DCHECK(notified_); |
| notified_ = false; |
| return true; |
| } |
| #endif // OS_WIN |
| } // namespace mozc |