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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/atomic_sequence_num.h
parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
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Add m-esr52 at 52.6.0
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1 files changed, 62 insertions, 0 deletions
diff --git a/ipc/chromium/src/base/atomic_sequence_num.h b/ipc/chromium/src/base/atomic_sequence_num.h
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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) 2012 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.
+
+#ifndef BASE_ATOMIC_SEQUENCE_NUM_H_
+#define BASE_ATOMIC_SEQUENCE_NUM_H_
+
+#include "base/atomicops.h"
+#include "base/basictypes.h"
+
+namespace base {
+
+class AtomicSequenceNumber;
+
+// Static (POD) AtomicSequenceNumber that MUST be used in global scope (or
+// non-function scope) ONLY. This implementation does not generate any static
+// initializer. Note that it does not implement any constructor which means
+// that its fields are not initialized except when it is stored in the global
+// data section (.data in ELF). If you want to allocate an atomic sequence
+// number on the stack (or heap), please use the AtomicSequenceNumber class
+// declared below.
+class StaticAtomicSequenceNumber {
+ public:
+ inline int GetNext() {
+ return static_cast<int>(
+ base::subtle::NoBarrier_AtomicIncrement(&seq_, 1) - 1);
+ }
+
+ private:
+ friend class AtomicSequenceNumber;
+
+ inline void Reset() {
+ base::subtle::Release_Store(&seq_, 0);
+ }
+
+ base::subtle::Atomic32 seq_;
+};
+
+// AtomicSequenceNumber that can be stored and used safely (i.e. its fields are
+// always initialized as opposed to StaticAtomicSequenceNumber declared above).
+// Please use StaticAtomicSequenceNumber if you want to declare an atomic
+// sequence number in the global scope.
+class AtomicSequenceNumber {
+ public:
+ AtomicSequenceNumber() {
+ seq_.Reset();
+ }
+
+ inline int GetNext() {
+ return seq_.GetNext();
+ }
+
+ private:
+ StaticAtomicSequenceNumber seq_;
+ DISALLOW_COPY_AND_ASSIGN(AtomicSequenceNumber);
+};
+
+} // namespace base
+
+#endif // BASE_ATOMIC_SEQUENCE_NUM_H_