You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
45 lines
1.3 KiB
45 lines
1.3 KiB
// Copyright (c) 2011 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_SYNCHRONIZATION_ATOMIC_FLAG_H_
|
|
#define BASE_SYNCHRONIZATION_ATOMIC_FLAG_H_
|
|
|
|
#include "base/atomicops.h"
|
|
#include "base/base_export.h"
|
|
#include "base/macros.h"
|
|
#include "base/sequence_checker.h"
|
|
|
|
namespace base {
|
|
|
|
// A flag that can safely be set from one thread and read from other threads.
|
|
//
|
|
// This class IS NOT intended for synchronization between threads.
|
|
class BASE_EXPORT AtomicFlag {
|
|
public:
|
|
AtomicFlag();
|
|
~AtomicFlag() = default;
|
|
|
|
// Set the flag. Must always be called from the same sequence.
|
|
void Set();
|
|
|
|
// Returns true iff the flag was set. If this returns true, the current thread
|
|
// is guaranteed to be synchronized with all memory operations on the sequence
|
|
// which invoked Set() up until at least the first call to Set() on it.
|
|
bool IsSet() const;
|
|
|
|
// Resets the flag. Be careful when using this: callers might not expect
|
|
// IsSet() to return false after returning true once.
|
|
void UnsafeResetForTesting();
|
|
|
|
private:
|
|
base::subtle::Atomic32 flag_ = 0;
|
|
SequenceChecker set_sequence_checker_;
|
|
|
|
DISALLOW_COPY_AND_ASSIGN(AtomicFlag);
|
|
};
|
|
|
|
} // namespace base
|
|
|
|
#endif // BASE_SYNCHRONIZATION_ATOMIC_FLAG_H_
|