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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
commit5f8de423f190bbb79a62f804151bc24824fa32d8 (patch)
tree10027f336435511475e392454359edea8e25895d /ipc/chromium/src/base/lock_impl_win.cc
parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (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.cc75
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
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+++ b/ipc/chromium/src/base/lock_impl_win.cc
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+/* -*- 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