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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.
#include "src/base/platform/semaphore.h"
#if V8_OS_MACOSX
#include <mach/mach_init.h>
#include <mach/task.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) {
kern_return_t result = semaphore_create(
mach_task_self(), &native_handle_, SYNC_POLICY_FIFO, count);
DCHECK_EQ(KERN_SUCCESS, result);
USE(result);
}
Semaphore::~Semaphore() {
kern_return_t result = semaphore_destroy(mach_task_self(), native_handle_);
DCHECK_EQ(KERN_SUCCESS, result);
USE(result);
}
void Semaphore::Signal() {
kern_return_t result = semaphore_signal(native_handle_);
DCHECK_EQ(KERN_SUCCESS, result);
USE(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);
}
}
bool Semaphore::WaitFor(const TimeDelta& rel_time) {
TimeTicks now = TimeTicks::Now();
TimeTicks end = now + rel_time;
while (true) {
mach_timespec_t ts;
if (now >= end) {
// Return immediately if semaphore was not signalled.
ts.tv_sec = 0;
ts.tv_nsec = 0;
} else {
ts = (end - now).ToMachTimespec();
}
kern_return_t result = semaphore_timedwait(native_handle_, ts);
if (result == KERN_SUCCESS) return true; // Semaphore was signalled.
if (result == KERN_OPERATION_TIMED_OUT) return false; // Timeout.
DCHECK_EQ(KERN_ABORTED, result);
now = TimeTicks::Now();
}
}
#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.
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);
}
}
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;
}
}
}
#endif // V8_OS_MACOSX
} // namespace base
} // namespace v8
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