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//===-- Support/MutexGuard.h - Acquire/Release Mutex In Scope ---*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// This file defines a guard for a block of code that ensures a Mutex is locked
// upon construction and released upon destruction.
#include "llvm/Support/Mutex.h"
namespace llvm {
/// Instances of this class acquire a given Mutex Lock when constructed and
/// hold that lock until destruction. The intention is to instantiate one of
/// these on the stack at the top of some scope to be assured that C++
/// destruction of the object will always release the Mutex and thus avoid
/// a host of nasty multi-threading problems in the face of exceptions, etc.
/// Guard a section of code with a Mutex.
class MutexGuard {
sys::Mutex &M;
MutexGuard(const MutexGuard &) = delete;
void operator=(const MutexGuard &) = delete;
MutexGuard(sys::Mutex &m) : M(m) { M.lock(); }
~MutexGuard() { M.unlock(); }
/// holds - Returns true if this locker instance holds the specified lock.
/// This is mostly used in assertions to validate that the correct mutex
/// is held.
bool holds(const sys::Mutex& lock) const { return &M == &lock; }