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38 lines
1.2 KiB
C++
38 lines
1.2 KiB
C++
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// Copyright (c) 2011 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "base/synchronization/lock_impl.h"
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#include "base/debug/activity_tracker.h"
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namespace base {
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namespace internal {
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LockImpl::LockImpl() : native_handle_(SRWLOCK_INIT) {}
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LockImpl::~LockImpl() = default;
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bool LockImpl::Try() {
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return !!::TryAcquireSRWLockExclusive(&native_handle_);
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}
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void LockImpl::Lock() {
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// The ScopedLockAcquireActivity below is relatively expensive and so its
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// actions can become significant due to the very large number of locks
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// that tend to be used throughout the build. To avoid this cost in the
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// vast majority of the calls, simply "try" the lock first and only do the
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// (tracked) blocking call if that fails. Since "try" itself is a system
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// call, and thus also somewhat expensive, don't bother with it unless
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// tracking is actually enabled.
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if (base::debug::GlobalActivityTracker::IsEnabled())
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if (Try())
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return;
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base::debug::ScopedLockAcquireActivity lock_activity(this);
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::AcquireSRWLockExclusive(&native_handle_);
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}
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} // namespace internal
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} // namespace base
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