1 files changed, 99 insertions, 0 deletions
diff --git a/base/synchronization/waitable_event_win.cc b/base/synchronization/waitable_event_win.cc
new file mode 100644
index 0000000..0fcf488
--- /dev/null
+++ b/base/synchronization/waitable_event_win.cc
@@ -0,0 +1,99 @@
+// Copyright (c) 2011 The Chromium 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 "base/synchronization/waitable_event.h"
+
+#include <math.h>
+#include <windows.h>
+
+#include "base/logging.h"
+#include "base/time.h"
+
+namespace base {
+
+WaitableEvent::WaitableEvent(bool manual_reset, bool signaled)
+    : handle_(CreateEvent(NULL, manual_reset, signaled, NULL)) {
+  // We're probably going to crash anyways if this is ever NULL, so we might as
+  // well make our stack reports more informative by crashing here.
+  CHECK(handle_);
+}
+
+WaitableEvent::WaitableEvent(HANDLE handle)
+    : handle_(handle) {
+  CHECK(handle) << "Tried to create WaitableEvent from NULL handle";
+}
+
+WaitableEvent::~WaitableEvent() {
+  CloseHandle(handle_);
+}
+
+HANDLE WaitableEvent::Release() {
+  HANDLE rv = handle_;
+  handle_ = INVALID_HANDLE_VALUE;
+  return rv;
+}
+
+void WaitableEvent::Reset() {
+  ResetEvent(handle_);
+}
+
+void WaitableEvent::Signal() {
+  SetEvent(handle_);
+}
+
+bool WaitableEvent::IsSignaled() {
+  return TimedWait(TimeDelta::FromMilliseconds(0));
+}
+
+bool WaitableEvent::Wait() {
+  DWORD result = WaitForSingleObject(handle_, INFINITE);
+  // It is most unexpected that this should ever fail.  Help consumers learn
+  // about it if it should ever fail.
+  DCHECK(result == WAIT_OBJECT_0) << "WaitForSingleObject failed";
+  return result == WAIT_OBJECT_0;
+}
+
+bool WaitableEvent::TimedWait(const TimeDelta& max_time) {
+  DCHECK(max_time >= TimeDelta::FromMicroseconds(0));
+  // Be careful here.  TimeDelta has a precision of microseconds, but this API
+  // is in milliseconds.  If there are 5.5ms left, should the delay be 5 or 6?
+  // It should be 6 to avoid returning too early.
+  double timeout = ceil(max_time.InMillisecondsF());
+  DWORD result = WaitForSingleObject(handle_, static_cast<DWORD>(timeout));
+  switch (result) {
+    case WAIT_OBJECT_0:
+      return true;
+    case WAIT_TIMEOUT:
+      return false;
+  }
+  // It is most unexpected that this should ever fail.  Help consumers learn
+  // about it if it should ever fail.
+  NOTREACHED() << "WaitForSingleObject failed";
+  return false;
+}
+
+// static
+size_t WaitableEvent::WaitMany(WaitableEvent** events, size_t count) {
+  HANDLE handles[MAXIMUM_WAIT_OBJECTS];
+  CHECK_LE(count, MAXIMUM_WAIT_OBJECTS)
+      << "Can only wait on " << MAXIMUM_WAIT_OBJECTS << " with WaitMany";
+
+  for (size_t i = 0; i < count; ++i)
+    handles[i] = events[i]->handle();
+
+  // The cast is safe because count is small - see the CHECK above.
+  DWORD result =
+      WaitForMultipleObjects(static_cast<DWORD>(count),
+                             handles,
+                             FALSE,      // don't wait for all the objects
+                             INFINITE);  // no timeout
+  if (result >= WAIT_OBJECT_0 + count) {
+    NOTREACHED() << "WaitForMultipleObjects failed: " << GetLastError();
+    return 0;
+  }
+
+  return result - WAIT_OBJECT_0;
+}
+
+}  // namespace base