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author | Matt A. Tobin <mattatobin@localhost.localdomain> | 2018-02-02 04:16:08 -0500 |
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committer | Matt A. Tobin <mattatobin@localhost.localdomain> | 2018-02-02 04:16:08 -0500 |
commit | 5f8de423f190bbb79a62f804151bc24824fa32d8 (patch) | |
tree | 10027f336435511475e392454359edea8e25895d /ipc/chromium/src/base/lock_impl_win.cc | |
parent | 49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff) | |
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Add m-esr52 at 52.6.0
Diffstat (limited to 'ipc/chromium/src/base/lock_impl_win.cc')
-rw-r--r-- | ipc/chromium/src/base/lock_impl_win.cc | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/ipc/chromium/src/base/lock_impl_win.cc b/ipc/chromium/src/base/lock_impl_win.cc new file mode 100644 index 000000000..2a50fb234 --- /dev/null +++ b/ipc/chromium/src/base/lock_impl_win.cc @@ -0,0 +1,75 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +// Copyright (c) 2006-2008 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/lock_impl.h" +#include "base/logging.h" + +// NOTE: Although windows critical sections support recursive locks, we do not +// allow this, and we will commonly fire a DCHECK() if a thread attempts to +// acquire the lock a second time (while already holding it). + +LockImpl::LockImpl() { +#ifndef NDEBUG + recursion_count_shadow_ = 0; + recursion_used_ = false; + owning_thread_id_ = 0; +#endif // NDEBUG + // The second parameter is the spin count, for short-held locks it avoid the + // contending thread from going to sleep which helps performance greatly. + ::InitializeCriticalSectionAndSpinCount(&os_lock_, 2000); +} + +LockImpl::~LockImpl() { + ::DeleteCriticalSection(&os_lock_); +} + +bool LockImpl::Try() { + if (::TryEnterCriticalSection(&os_lock_) != FALSE) { +#ifndef NDEBUG + // ONLY access data after locking. + owning_thread_id_ = PlatformThread::CurrentId(); + DCHECK_NE(owning_thread_id_, 0); + recursion_count_shadow_++; + if (2 == recursion_count_shadow_ && !recursion_used_) { + recursion_used_ = true; + DCHECK(false); // Catch accidental redundant lock acquisition. + } +#endif + return true; + } + return false; +} + +void LockImpl::Lock() { + ::EnterCriticalSection(&os_lock_); +#ifndef NDEBUG + // ONLY access data after locking. + owning_thread_id_ = PlatformThread::CurrentId(); + DCHECK_NE(owning_thread_id_, 0); + recursion_count_shadow_++; + if (2 == recursion_count_shadow_ && !recursion_used_) { + recursion_used_ = true; + DCHECK(false); // Catch accidental redundant lock acquisition. + } +#endif // NDEBUG +} + +void LockImpl::Unlock() { +#ifndef NDEBUG + --recursion_count_shadow_; // ONLY access while lock is still held. + DCHECK(0 <= recursion_count_shadow_); + owning_thread_id_ = 0; +#endif // NDEBUG + ::LeaveCriticalSection(&os_lock_); +} + +// In non-debug builds, this method is declared as an empty inline method. +#ifndef NDEBUG +void LockImpl::AssertAcquired() const { + DCHECK(recursion_count_shadow_ > 0); + DCHECK_EQ(owning_thread_id_, PlatformThread::CurrentId()); +} +#endif |