semaphore.cc 4.8 KB
Newer Older
1
// Copyright 2013 the V8 project authors. All rights reserved.
2 3
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
4

5
#include "src/base/platform/semaphore.h"
6 7 8 9 10 11

#if V8_OS_MACOSX
#include <mach/mach_init.h>
#include <mach/task.h>
#endif

12
#include <errno.h>
13

14
#include "src/base/logging.h"
15
#include "src/base/platform/elapsed-timer.h"
16
#include "src/base/platform/time.h"
17 18

namespace v8 {
19
namespace base {
20 21 22 23 24 25

#if V8_OS_MACOSX

Semaphore::Semaphore(int count) {
  kern_return_t result = semaphore_create(
      mach_task_self(), &native_handle_, SYNC_POLICY_FIFO, count);
26
  DCHECK_EQ(KERN_SUCCESS, result);
27 28 29 30 31 32
  USE(result);
}


Semaphore::~Semaphore() {
  kern_return_t result = semaphore_destroy(mach_task_self(), native_handle_);
33
  DCHECK_EQ(KERN_SUCCESS, result);
34 35 36 37 38 39
  USE(result);
}


void Semaphore::Signal() {
  kern_return_t result = semaphore_signal(native_handle_);
40
  DCHECK_EQ(KERN_SUCCESS, result);
41 42 43 44 45 46 47 48
  USE(result);
}


void Semaphore::Wait() {
  while (true) {
    kern_return_t result = semaphore_wait(native_handle_);
    if (result == KERN_SUCCESS) return;  // Semaphore was signalled.
49
    DCHECK_EQ(KERN_ABORTED, result);
50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68
  }
}


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.
69
    DCHECK_EQ(KERN_ABORTED, result);
70 71 72 73 74 75 76
    now = TimeTicks::Now();
  }
}

#elif V8_OS_POSIX

Semaphore::Semaphore(int count) {
77
  DCHECK(count >= 0);
78
  int result = sem_init(&native_handle_, 0, count);
79
  DCHECK_EQ(0, result);
80 81 82 83 84 85
  USE(result);
}


Semaphore::~Semaphore() {
  int result = sem_destroy(&native_handle_);
86
  DCHECK_EQ(0, result);
87 88 89 90 91 92
  USE(result);
}


void Semaphore::Signal() {
  int result = sem_post(&native_handle_);
93
  DCHECK_EQ(0, result);
94 95 96 97 98 99 100 101 102
  USE(result);
}


void Semaphore::Wait() {
  while (true) {
    int result = sem_wait(&native_handle_);
    if (result == 0) return;  // Semaphore was signalled.
    // Signal caused spurious wakeup.
103 104
    DCHECK_EQ(-1, result);
    DCHECK_EQ(EINTR, errno);
105 106 107 108 109
  }
}


bool Semaphore::WaitFor(const TimeDelta& rel_time) {
110 111 112 113 114 115 116
#if V8_OS_NACL
  // PNaCL doesn't support sem_timedwait, do ugly busy waiting.
  ElapsedTimer timer;
  timer.Start();
  do {
    int result = sem_trywait(&native_handle_);
    if (result == 0) return true;
jarin@chromium.org's avatar
jarin@chromium.org committed
117
    DCHECK(errno == EAGAIN || errno == EINTR);
118 119 120
  } while (!timer.HasExpired(rel_time));
  return false;
#else
121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140
  // 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.
141 142
    DCHECK_EQ(-1, result);
    DCHECK_EQ(EINTR, errno);
143
  }
144
#endif
145 146 147 148 149
}

#elif V8_OS_WIN

Semaphore::Semaphore(int count) {
150
  DCHECK(count >= 0);
151
  native_handle_ = ::CreateSemaphoreA(NULL, count, 0x7fffffff, NULL);
152
  DCHECK(native_handle_ != NULL);
153 154 155 156 157
}


Semaphore::~Semaphore() {
  BOOL result = CloseHandle(native_handle_);
158
  DCHECK(result);
159 160 161 162 163 164 165
  USE(result);
}


void Semaphore::Signal() {
  LONG dummy;
  BOOL result = ReleaseSemaphore(native_handle_, 1, &dummy);
166
  DCHECK(result);
167 168 169 170 171 172
  USE(result);
}


void Semaphore::Wait() {
  DWORD result = WaitForSingleObject(native_handle_, INFINITE);
173
  DCHECK(result == WAIT_OBJECT_0);
174 175 176 177 178 179 180 181 182 183 184 185 186 187
  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;
      }
188
      DCHECK(result == WAIT_TIMEOUT);
189 190 191 192 193 194 195
      now = TimeTicks::Now();
    } else {
      DWORD result = WaitForSingleObject(
          native_handle_, (msec < 0) ? 0 : static_cast<DWORD>(msec));
      if (result == WAIT_TIMEOUT) {
        return false;
      }
196
      DCHECK(result == WAIT_OBJECT_0);
197 198 199 200 201 202 203
      return true;
    }
  }
}

#endif  // V8_OS_MACOSX

204
} }  // namespace v8::base