// Copyright 2013 the V8 project authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #include "src/base/platform/semaphore.h" #if V8_OS_MACOSX #include <dispatch/dispatch.h> #endif #include <errno.h> #include "src/base/logging.h" #include "src/base/platform/elapsed-timer.h" #include "src/base/platform/time.h" namespace v8 { namespace base { #if V8_OS_MACOSX Semaphore::Semaphore(int count) { native_handle_ = dispatch_semaphore_create(count); DCHECK(native_handle_); } Semaphore::~Semaphore() { dispatch_release(native_handle_); } void Semaphore::Signal() { dispatch_semaphore_signal(native_handle_); } void Semaphore::Wait() { dispatch_semaphore_wait(native_handle_, DISPATCH_TIME_FOREVER); } bool Semaphore::WaitFor(const TimeDelta& rel_time) { dispatch_time_t timeout = dispatch_time(DISPATCH_TIME_NOW, rel_time.InNanoseconds()); return dispatch_semaphore_wait(native_handle_, timeout) == 0; } #elif V8_OS_POSIX Semaphore::Semaphore(int count) { DCHECK_GE(count, 0); int result = sem_init(&native_handle_, 0, count); DCHECK_EQ(0, result); USE(result); } Semaphore::~Semaphore() { int result = sem_destroy(&native_handle_); DCHECK_EQ(0, result); USE(result); } void Semaphore::Signal() { int result = sem_post(&native_handle_); // This check may fail with <libc-2.21, which we use on the try bots, if the // semaphore is destroyed while sem_post is still executed. A work around is // to extend the lifetime of the semaphore. if (result != 0) { FATAL("Error when signaling semaphore, errno: %d", errno); } } void Semaphore::Wait() { while (true) { int result = sem_wait(&native_handle_); if (result == 0) return; // Semaphore was signalled. // Signal caused spurious wakeup. DCHECK_EQ(-1, result); DCHECK_EQ(EINTR, errno); } } bool Semaphore::WaitFor(const TimeDelta& rel_time) { // Compute the time for end of timeout. const Time time = Time::NowFromSystemTime() + rel_time; const struct timespec ts = time.ToTimespec(); // Wait for semaphore signalled or timeout. while (true) { int result = sem_timedwait(&native_handle_, &ts); if (result == 0) return true; // Semaphore was signalled. #if V8_LIBC_GLIBC && !V8_GLIBC_PREREQ(2, 4) if (result > 0) { // sem_timedwait in glibc prior to 2.3.4 returns the errno instead of -1. errno = result; result = -1; } #endif if (result == -1 && errno == ETIMEDOUT) { // Timed out while waiting for semaphore. return false; } // Signal caused spurious wakeup. DCHECK_EQ(-1, result); DCHECK_EQ(EINTR, errno); } } #elif V8_OS_WIN Semaphore::Semaphore(int count) { DCHECK_GE(count, 0); native_handle_ = ::CreateSemaphoreA(nullptr, count, 0x7FFFFFFF, nullptr); DCHECK_NOT_NULL(native_handle_); } Semaphore::~Semaphore() { BOOL result = CloseHandle(native_handle_); DCHECK(result); USE(result); } void Semaphore::Signal() { LONG dummy; BOOL result = ReleaseSemaphore(native_handle_, 1, &dummy); DCHECK(result); USE(result); } void Semaphore::Wait() { DWORD result = WaitForSingleObject(native_handle_, INFINITE); DCHECK(result == WAIT_OBJECT_0); USE(result); } bool Semaphore::WaitFor(const TimeDelta& rel_time) { TimeTicks now = TimeTicks::Now(); TimeTicks end = now + rel_time; while (true) { int64_t msec = (end - now).InMilliseconds(); if (msec >= static_cast<int64_t>(INFINITE)) { DWORD result = WaitForSingleObject(native_handle_, INFINITE - 1); if (result == WAIT_OBJECT_0) { return true; } DCHECK(result == WAIT_TIMEOUT); now = TimeTicks::Now(); } else { DWORD result = WaitForSingleObject( native_handle_, (msec < 0) ? 0 : static_cast<DWORD>(msec)); if (result == WAIT_TIMEOUT) { return false; } DCHECK(result == WAIT_OBJECT_0); return true; } } } #elif V8_OS_STARBOARD Semaphore::Semaphore(int count) : native_handle_(count) { DCHECK_GE(count, 0); } Semaphore::~Semaphore() {} void Semaphore::Signal() { native_handle_.Put(); } void Semaphore::Wait() { native_handle_.Take(); } bool Semaphore::WaitFor(const TimeDelta& rel_time) { SbTime microseconds = rel_time.InMicroseconds(); return native_handle_.TakeWait(microseconds); } #endif // V8_OS_MACOSX } // namespace base } // namespace v8