Create 2062 release branch for CEF3.

git-svn-id: https://chromiumembedded.googlecode.com/svn/branches/2062@1783 5089003a-bbd8-11dd-ad1f-f1f9622dbc98

include/base/cef_atomic_ref_count.h

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+// Copyright (c) 2014 Marshall A. Greenblatt. Portions copyright (c) 2011
+// Google Inc. All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//    * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//    * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//    * Neither the name of Google Inc. nor the name Chromium Embedded
+// Framework nor the names of its contributors may be used to endorse
+// or promote products derived from this software without specific prior
+// written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// This is a low level implementation of atomic semantics for reference
+// counting.  Please use cef_ref_counted.h directly instead.
+//
+// The Chromium implementation includes annotations to avoid some false
+// positives when using data race detection tools. Annotations are not
+// currently supported by the CEF implementation.
+
+#ifndef CEF_INCLUDE_BASE_CEF_ATOMIC_REF_COUNT_H_
+#define CEF_INCLUDE_BASE_CEF_ATOMIC_REF_COUNT_H_
+#pragma once
+
+#if defined(BASE_ATOMIC_REF_COUNT_H_)
+// Do nothing if the Chromium header has already been included.
+// This can happen in cases where Chromium code is used directly by the
+// client application. When using Chromium code directly always include
+// the Chromium header first to avoid type conflicts.
+#elif defined(BUILDING_CEF_SHARED)
+// When building CEF include the Chromium header directly.
+#include "base/atomic_ref_count.h"
+#else  // !BUILDING_CEF_SHARED
+// The following is substantially similar to the Chromium implementation.
+// If the Chromium implementation diverges the below implementation should be
+// updated to match.
+
+#include "include/base/cef_atomicops.h"
+
+// Annotations are not currently supported.
+#define ANNOTATE_HAPPENS_BEFORE(obj) /* empty */
+#define ANNOTATE_HAPPENS_AFTER(obj) /* empty */
+
+namespace base {
+
+typedef subtle::Atomic32 AtomicRefCount;
+
+// Increment a reference count by "increment", which must exceed 0.
+inline void AtomicRefCountIncN(volatile AtomicRefCount *ptr,
+                               AtomicRefCount increment) {
+  subtle::NoBarrier_AtomicIncrement(ptr, increment);
+}
+
+// Decrement a reference count by "decrement", which must exceed 0,
+// and return whether the result is non-zero.
+// Insert barriers to ensure that state written before the reference count
+// became zero will be visible to a thread that has just made the count zero.
+inline bool AtomicRefCountDecN(volatile AtomicRefCount *ptr,
+                               AtomicRefCount decrement) {
+  ANNOTATE_HAPPENS_BEFORE(ptr);
+  bool res = (subtle::Barrier_AtomicIncrement(ptr, -decrement) != 0);
+  if (!res) {
+    ANNOTATE_HAPPENS_AFTER(ptr);
+  }
+  return res;
+}
+
+// Increment a reference count by 1.
+inline void AtomicRefCountInc(volatile AtomicRefCount *ptr) {
+  base::AtomicRefCountIncN(ptr, 1);
+}
+
+// Decrement a reference count by 1 and return whether the result is non-zero.
+// Insert barriers to ensure that state written before the reference count
+// became zero will be visible to a thread that has just made the count zero.
+inline bool AtomicRefCountDec(volatile AtomicRefCount *ptr) {
+  return base::AtomicRefCountDecN(ptr, 1);
+}
+
+// Return whether the reference count is one.  If the reference count is used
+// in the conventional way, a refrerence count of 1 implies that the current
+// thread owns the reference and no other thread shares it.  This call performs
+// the test for a reference count of one, and performs the memory barrier
+// needed for the owning thread to act on the object, knowing that it has
+// exclusive access to the object.
+inline bool AtomicRefCountIsOne(volatile AtomicRefCount *ptr) {
+  bool res = (subtle::Acquire_Load(ptr) == 1);
+  if (res) {
+    ANNOTATE_HAPPENS_AFTER(ptr);
+  }
+  return res;
+}
+
+// Return whether the reference count is zero.  With conventional object
+// referencing counting, the object will be destroyed, so the reference count
+// should never be zero.  Hence this is generally used for a debug check.
+inline bool AtomicRefCountIsZero(volatile AtomicRefCount *ptr) {
+  bool res = (subtle::Acquire_Load(ptr) == 0);
+  if (res) {
+    ANNOTATE_HAPPENS_AFTER(ptr);
+  }
+  return res;
+}
+
+}  // namespace base
+
+#endif  // !BUILDING_CEF_SHARED
+
+#endif  // CEF_INCLUDE_BASE_CEF_ATOMIC_REF_COUNT_H_