1 // Copyright 2013 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #include "src/base/platform/semaphore.h"
8 #include <mach/mach_init.h>
14 #include "src/base/logging.h"
15 #include "src/base/platform/elapsed-timer.h"
16 #include "src/base/platform/time.h"
23 Semaphore::Semaphore(int count) {
24 kern_return_t result = semaphore_create(
25 mach_task_self(), &native_handle_, SYNC_POLICY_FIFO, count);
26 DCHECK_EQ(KERN_SUCCESS, result);
31 Semaphore::~Semaphore() {
32 kern_return_t result = semaphore_destroy(mach_task_self(), native_handle_);
33 DCHECK_EQ(KERN_SUCCESS, result);
38 void Semaphore::Signal() {
39 kern_return_t result = semaphore_signal(native_handle_);
40 DCHECK_EQ(KERN_SUCCESS, result);
45 void Semaphore::Wait() {
47 kern_return_t result = semaphore_wait(native_handle_);
48 if (result == KERN_SUCCESS) return; // Semaphore was signalled.
49 DCHECK_EQ(KERN_ABORTED, result);
54 bool Semaphore::WaitFor(const TimeDelta& rel_time) {
55 TimeTicks now = TimeTicks::Now();
56 TimeTicks end = now + rel_time;
60 // Return immediately if semaphore was not signalled.
64 ts = (end - now).ToMachTimespec();
66 kern_return_t result = semaphore_timedwait(native_handle_, ts);
67 if (result == KERN_SUCCESS) return true; // Semaphore was signalled.
68 if (result == KERN_OPERATION_TIMED_OUT) return false; // Timeout.
69 DCHECK_EQ(KERN_ABORTED, result);
70 now = TimeTicks::Now();
76 Semaphore::Semaphore(int count) {
78 int result = sem_init(&native_handle_, 0, count);
84 Semaphore::~Semaphore() {
85 int result = sem_destroy(&native_handle_);
91 void Semaphore::Signal() {
92 int result = sem_post(&native_handle_);
98 void Semaphore::Wait() {
100 int result = sem_wait(&native_handle_);
101 if (result == 0) return; // Semaphore was signalled.
102 // Signal caused spurious wakeup.
103 DCHECK_EQ(-1, result);
104 DCHECK_EQ(EINTR, errno);
109 bool Semaphore::WaitFor(const TimeDelta& rel_time) {
111 // PNaCL doesn't support sem_timedwait, do ugly busy waiting.
115 int result = sem_trywait(&native_handle_);
116 if (result == 0) return true;
117 DCHECK(errno == EAGAIN || errno == EINTR);
118 } while (!timer.HasExpired(rel_time));
121 // Compute the time for end of timeout.
122 const Time time = Time::NowFromSystemTime() + rel_time;
123 const struct timespec ts = time.ToTimespec();
125 // Wait for semaphore signalled or timeout.
127 int result = sem_timedwait(&native_handle_, &ts);
128 if (result == 0) return true; // Semaphore was signalled.
129 #if V8_LIBC_GLIBC && !V8_GLIBC_PREREQ(2, 4)
131 // sem_timedwait in glibc prior to 2.3.4 returns the errno instead of -1.
136 if (result == -1 && errno == ETIMEDOUT) {
137 // Timed out while waiting for semaphore.
140 // Signal caused spurious wakeup.
141 DCHECK_EQ(-1, result);
142 DCHECK_EQ(EINTR, errno);
149 Semaphore::Semaphore(int count) {
151 native_handle_ = ::CreateSemaphoreA(NULL, count, 0x7fffffff, NULL);
152 DCHECK(native_handle_ != NULL);
156 Semaphore::~Semaphore() {
157 BOOL result = CloseHandle(native_handle_);
163 void Semaphore::Signal() {
165 BOOL result = ReleaseSemaphore(native_handle_, 1, &dummy);
171 void Semaphore::Wait() {
172 DWORD result = WaitForSingleObject(native_handle_, INFINITE);
173 DCHECK(result == WAIT_OBJECT_0);
178 bool Semaphore::WaitFor(const TimeDelta& rel_time) {
179 TimeTicks now = TimeTicks::Now();
180 TimeTicks end = now + rel_time;
182 int64_t msec = (end - now).InMilliseconds();
183 if (msec >= static_cast<int64_t>(INFINITE)) {
184 DWORD result = WaitForSingleObject(native_handle_, INFINITE - 1);
185 if (result == WAIT_OBJECT_0) {
188 DCHECK(result == WAIT_TIMEOUT);
189 now = TimeTicks::Now();
191 DWORD result = WaitForSingleObject(
192 native_handle_, (msec < 0) ? 0 : static_cast<DWORD>(msec));
193 if (result == WAIT_TIMEOUT) {
196 DCHECK(result == WAIT_OBJECT_0);
202 #endif // V8_OS_MACOSX
204 } } // namespace v8::base