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// 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.
//
// Based on
// https://cs.chromium.org/chromium/src/v8/src/base/platform/semaphore.cc
#include "util/semaphore.h"
#include "base/logging.h"
#if defined(OS_MACOSX)
Semaphore::Semaphore(int count) {
kern_return_t result = semaphore_create(mach_task_self(), &native_handle_,
SYNC_POLICY_FIFO, count);
DCHECK_EQ(KERN_SUCCESS, result);
}
Semaphore::~Semaphore() {
kern_return_t result = semaphore_destroy(mach_task_self(), native_handle_);
DCHECK_EQ(KERN_SUCCESS, result);
}
void Semaphore::Signal() {
kern_return_t result = semaphore_signal(native_handle_);
DCHECK_EQ(KERN_SUCCESS, result);
}
void Semaphore::Wait() {
while (true) {
kern_return_t result = semaphore_wait(native_handle_);
if (result == KERN_SUCCESS)
return; // Semaphore was signalled.
DCHECK_EQ(KERN_ABORTED, result);
}
}
#elif defined(OS_LINUX) || defined(OS_AIX)
Semaphore::Semaphore(int count) {
DCHECK_GE(count, 0);
int result = sem_init(&native_handle_, 0, count);
DCHECK_EQ(0, result);
}
Semaphore::~Semaphore() {
int result = sem_destroy(&native_handle_);
DCHECK_EQ(0, 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.
CHECK_EQ(0, result);
}
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);
}
}
#elif defined(OS_WIN)
Semaphore::Semaphore(int count) {
DCHECK_GE(count, 0);
native_handle_ = ::CreateSemaphoreA(nullptr, count, 0x7FFFFFFF, nullptr);
DCHECK(native_handle_);
}
Semaphore::~Semaphore() {
BOOL result = CloseHandle(native_handle_);
DCHECK(result);
}
void Semaphore::Signal() {
LONG dummy;
BOOL result = ReleaseSemaphore(native_handle_, 1, &dummy);
DCHECK(result);
}
void Semaphore::Wait() {
DWORD result = WaitForSingleObject(native_handle_, INFINITE);
DCHECK(result == WAIT_OBJECT_0);
}
#endif
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