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// 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/lock_impl.h"
#include "base/debug/activity_tracker.h"
#include <windows.h>
namespace base {
namespace internal {
LockImpl::LockImpl() : native_handle_(SRWLOCK_INIT) {}
LockImpl::~LockImpl() = default;
bool LockImpl::Try() {
return !!::TryAcquireSRWLockExclusive(
reinterpret_cast<PSRWLOCK>(&native_handle_));
}
void LockImpl::Lock() {
// The ScopedLockAcquireActivity below is relatively expensive and so its
// actions can become significant due to the very large number of locks
// that tend to be used throughout the build. To avoid this cost in the
// vast majority of the calls, simply "try" the lock first and only do the
// (tracked) blocking call if that fails. Since "try" itself is a system
// call, and thus also somewhat expensive, don't bother with it unless
// tracking is actually enabled.
if (base::debug::GlobalActivityTracker::IsEnabled())
if (Try())
return;
base::debug::ScopedLockAcquireActivity lock_activity(this);
::AcquireSRWLockExclusive(reinterpret_cast<PSRWLOCK>(&native_handle_));
}
} // namespace internal
} // namespace base
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