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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 01:47:29 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 01:47:29 +0000 |
commit | 0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d (patch) | |
tree | a31f07c9bcca9d56ce61e9a1ffd30ef350d513aa /security/sandbox/chromium/base/synchronization/atomic_flag.h | |
parent | Initial commit. (diff) | |
download | firefox-esr-0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d.tar.xz firefox-esr-0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d.zip |
Adding upstream version 115.8.0esr.upstream/115.8.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'security/sandbox/chromium/base/synchronization/atomic_flag.h')
-rw-r--r-- | security/sandbox/chromium/base/synchronization/atomic_flag.h | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/security/sandbox/chromium/base/synchronization/atomic_flag.h b/security/sandbox/chromium/base/synchronization/atomic_flag.h new file mode 100644 index 0000000000..f386a16cbd --- /dev/null +++ b/security/sandbox/chromium/base/synchronization/atomic_flag.h @@ -0,0 +1,50 @@ +// 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 <stdint.h> + +#include <atomic> + +#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(); + + // 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 { + // Inline here: this has a measurable performance impact on base::WeakPtr. + return flag_.load(std::memory_order_acquire) != 0; + } + + // Resets the flag. Be careful when using this: callers might not expect + // IsSet() to return false after returning true once. + void UnsafeResetForTesting(); + + private: + std::atomic<uint_fast8_t> flag_{0}; + SEQUENCE_CHECKER(set_sequence_checker_); + + DISALLOW_COPY_AND_ASSIGN(AtomicFlag); +}; + +} // namespace base + +#endif // BASE_SYNCHRONIZATION_ATOMIC_FLAG_H_ |