Import ConditionVariable class.

src/platform/condition-variable.cc

+// Copyright 2013 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "platform/condition-variable.h"
+
+#include <cerrno>
+#include <ctime>
+
+#include "platform/time.h"
+
+namespace v8 {
+namespace internal {
+
+#if V8_OS_POSIX
+
+ConditionVariable::ConditionVariable() {
+  // TODO(bmeurer): The test for V8_LIBRT_NOT_AVAILABLE is a temporary
+  // hack to support cross-compiling Chrome for Android in AOSP. Remove
+  // this once AOSP is fixed.
+#if (V8_OS_FREEBSD || V8_OS_NETBSD || V8_OS_OPENBSD || V8_LIBC_GLIBC) && \
+    !V8_LIBRT_NOT_AVAILABLE
+  // On Free/Net/OpenBSD and Linux with glibc we can change the time
+  // source for pthread_cond_timedwait() to use the monotonic clock.
+  pthread_condattr_t attr;
+  int result = pthread_condattr_init(&attr);
+  ASSERT_EQ(0, result);
+  result = pthread_condattr_setclock(&attr, CLOCK_MONOTONIC);
+  ASSERT_EQ(0, result);
+  result = pthread_cond_init(&native_handle_, &attr);
+  ASSERT_EQ(0, result);
+  result = pthread_condattr_destroy(&attr);
+#else
+  int result = pthread_cond_init(&native_handle_, NULL);
+#endif
+  ASSERT_EQ(0, result);
+  USE(result);
+}
+
+
+ConditionVariable::~ConditionVariable() {
+  int result = pthread_cond_destroy(&native_handle_);
+  ASSERT_EQ(0, result);
+  USE(result);
+}
+
+
+void ConditionVariable::NotifyOne() {
+  int result = pthread_cond_signal(&native_handle_);
+  ASSERT_EQ(0, result);
+  USE(result);
+}
+
+
+void ConditionVariable::NotifyAll() {
+  int result = pthread_cond_broadcast(&native_handle_);
+  ASSERT_EQ(0, result);
+  USE(result);
+}
+
+
+void ConditionVariable::Wait(Mutex* mutex) {
+  mutex->AssertHeldAndUnmark();
+  int result = pthread_cond_wait(&native_handle_, &mutex->native_handle());
+  ASSERT_EQ(0, result);
+  USE(result);
+  mutex->AssertUnheldAndMark();
+}
+
+
+bool ConditionVariable::WaitFor(Mutex* mutex, const TimeDelta& rel_time) {
+  struct timespec ts;
+  int result;
+  mutex->AssertHeldAndUnmark();
+#if V8_OS_MACOSX
+  // Mac OS X provides pthread_cond_timedwait_relative_np(), which does
+  // not depend on the real time clock, which is what you really WANT here!
+  ts = rel_time.ToTimespec();
+  ASSERT_GE(ts.tv_sec, 0);
+  ASSERT_GE(ts.tv_nsec, 0);
+  result = pthread_cond_timedwait_relative_np(
+      &native_handle_, &mutex->native_handle(), &ts);
+#else
+  // TODO(bmeurer): The test for V8_LIBRT_NOT_AVAILABLE is a temporary
+  // hack to support cross-compiling Chrome for Android in AOSP. Remove
+  // this once AOSP is fixed.
+#if (V8_OS_FREEBSD || V8_OS_NETBSD || V8_OS_OPENBSD || V8_LIBC_GLIBC) && \
+    !V8_LIBRT_NOT_AVAILABLE
+  // On Free/Net/OpenBSD and Linux with glibc we can change the time
+  // source for pthread_cond_timedwait() to use the monotonic clock.
+  result = clock_gettime(CLOCK_MONOTONIC, &ts);
+  ASSERT_EQ(0, result);
+  Time now = Time::FromTimespec(ts);
+#else
+  // The timeout argument to pthread_cond_timedwait() is in absolute time.
+  Time now = Time::NowFromSystemTime();
+#endif
+  Time end_time = now + rel_time;
+  ASSERT_GE(end_time, now);
+  ts = end_time.ToTimespec();
+  result = pthread_cond_timedwait(
+      &native_handle_, &mutex->native_handle(), &ts);
+#endif  // V8_OS_MACOSX
+  mutex->AssertUnheldAndMark();
+  if (result == ETIMEDOUT) {
+    return false;
+  }
+  ASSERT_EQ(0, result);
+  return true;
+}
+
+#elif V8_OS_WIN
+
+struct ConditionVariable::Event {
+  Event() : handle_(::CreateEventA(NULL, true, false, NULL)) {
+    ASSERT(handle_ != NULL);
+  }
+
+  ~Event() {
+    BOOL ok = ::CloseHandle(handle_);
+    ASSERT(ok);
+    USE(ok);
+  }
+
+  bool WaitFor(DWORD timeout_ms) {
+    DWORD result = ::WaitForSingleObject(handle_, timeout_ms);
+    if (result == WAIT_OBJECT_0) {
+      return true;
+    }
+    ASSERT(result == WAIT_TIMEOUT);
+    return false;
+  }
+
+  HANDLE handle_;
+  Event* next_;
+  HANDLE thread_;
+  volatile bool notified_;
+};
+
+
+ConditionVariable::NativeHandle::~NativeHandle() {
+  ASSERT(waitlist_ == NULL);
+
+  while (freelist_ != NULL) {
+    Event* event = freelist_;
+    freelist_ = event->next_;
+    delete event;
+  }
+}
+
+
+ConditionVariable::Event* ConditionVariable::NativeHandle::Pre() {
+  LockGuard<Mutex> lock_guard(&mutex_);
+
+  // Grab an event from the free list or create a new one.
+  Event* event = freelist_;
+  if (event != NULL) {
+    freelist_ = event->next_;
+  } else {
+    event = new Event;
+  }
+  event->thread_ = GetCurrentThread();
+  event->notified_ = false;
+
+#ifdef DEBUG
+  // The event must not be on the wait list.
+  for (Event* we = waitlist_; we != NULL; we = we->next_) {
+    ASSERT_NE(event, we);
+  }
+#endif
+
+  // Prepend the event to the wait list.
+  event->next_ = waitlist_;
+  waitlist_ = event;
+
+  return event;
+}
+
+
+void ConditionVariable::NativeHandle::Post(Event* event, bool result) {
+  LockGuard<Mutex> lock_guard(&mutex_);
+
+  // Remove the event from the wait list.
+  for (Event** wep = &waitlist_;; wep = &(*wep)->next_) {
+    ASSERT_NE(NULL, *wep);
+    if (*wep == event) {
+      *wep = event->next_;
+      break;
+    }
+  }
+
+#ifdef DEBUG
+  // The event must not be on the free list.
+  for (Event* fe = freelist_; fe != NULL; fe = fe->next_) {
+    ASSERT_NE(event, fe);
+  }
+#endif
+
+  // Reset the event.
+  BOOL ok = ::ResetEvent(event->handle_);
+  ASSERT(ok);
+  USE(ok);
+
+  // Insert the event into the free list.
+  event->next_ = freelist_;
+  freelist_ = event;
+
+  // Forward signals delivered after the timeout to the next waiting event.
+  if (!result && event->notified_ && waitlist_ != NULL) {
+    ok = ::SetEvent(waitlist_->handle_);
+    ASSERT(ok);
+    USE(ok);
+    waitlist_->notified_ = true;
+  }
+}
+
+
+ConditionVariable::ConditionVariable() {}
+
+
+ConditionVariable::~ConditionVariable() {}
+
+
+void ConditionVariable::NotifyOne() {
+  // Notify the thread with the highest priority in the waitlist
+  // that was not already signalled.
+  LockGuard<Mutex> lock_guard(native_handle_.mutex());
+  Event* highest_event = NULL;
+  int highest_priority = std::numeric_limits<int>::min();
+  for (Event* event = native_handle().waitlist();
+       event != NULL;
+       event = event->next_) {
+    if (event->notified_) {
+      continue;
+    }
+    int priority = GetThreadPriority(event->thread_);
+    ASSERT_NE(THREAD_PRIORITY_ERROR_RETURN, priority);
+    if (priority >= highest_priority) {
+      highest_priority = priority;
+      highest_event = event;
+    }
+  }
+  if (highest_event != NULL) {
+    ASSERT(!highest_event->notified_);
+    ::SetEvent(highest_event->handle_);
+    highest_event->notified_ = true;
+  }
+}
+
+
+void ConditionVariable::NotifyAll() {
+  // Notify all threads on the waitlist.
+  LockGuard<Mutex> lock_guard(native_handle_.mutex());
+  for (Event* event = native_handle().waitlist();
+       event != NULL;
+       event = event->next_) {
+    if (!event->notified_) {
+      ::SetEvent(event->handle_);
+      event->notified_ = true;
+    }
+  }
+}
+
+
+void ConditionVariable::Wait(Mutex* mutex) {
+  // Create and setup the wait event.
+  Event* event = native_handle_.Pre();
+
+  // Release the user mutex.
+  mutex->Unlock();
+
+  // Wait on the wait event.
+  while (!event->WaitFor(INFINITE))
+    ;
+
+  // Reaquire the user mutex.
+  mutex->Lock();
+
+  // Release the wait event (we must have been notified).
+  ASSERT(event->notified_);
+  native_handle_.Post(event, true);
+}
+
+
+bool ConditionVariable::WaitFor(Mutex* mutex, const TimeDelta& rel_time) {
+  // Create and setup the wait event.
+  Event* event = native_handle_.Pre();
+
+  // Release the user mutex.
+  mutex->Unlock();
+
+  // Wait on the wait event.
+  TimeTicks now = TimeTicks::Now();
+  TimeTicks end = now + rel_time;
+  bool result = false;
+  while (true) {
+    int64_t msec = (end - now).InMilliseconds();
+    if (msec >= static_cast<int64_t>(INFINITE)) {
+      result = event->WaitFor(INFINITE - 1);
+      if (result) {
+        break;
+      }
+      now = TimeTicks::Now();
+    } else {
+      result = event->WaitFor((msec < 0) ? 0 : static_cast<DWORD>(msec));
+      break;
+    }
+  }
+
+  // Reaquire the user mutex.
+  mutex->Lock();
+
+  // Release the wait event.
+  ASSERT(!result || event->notified_);
+  native_handle_.Post(event, result);
+
+  return result;
+}
+
+#endif  // V8_OS_POSIX
+
+} }  // namespace v8::internal