Yi Kong | 7bf2a68 | 2019-04-18 17:30:49 -0700 | [diff] [blame] | 1 | //===-- Support/MutexGuard.h - Acquire/Release Mutex In Scope ---*- C++ -*-===// |
| 2 | // |
| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 4 | // See https://llvm.org/LICENSE.txt for license information. |
| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 6 | // |
| 7 | //===----------------------------------------------------------------------===// |
| 8 | // |
| 9 | // This file defines a guard for a block of code that ensures a Mutex is locked |
| 10 | // upon construction and released upon destruction. |
| 11 | // |
| 12 | //===----------------------------------------------------------------------===// |
| 13 | |
| 14 | #ifndef LLVM_SUPPORT_MUTEXGUARD_H |
| 15 | #define LLVM_SUPPORT_MUTEXGUARD_H |
| 16 | |
| 17 | #include "llvm/Support/Mutex.h" |
| 18 | |
| 19 | namespace llvm { |
| 20 | /// Instances of this class acquire a given Mutex Lock when constructed and |
| 21 | /// hold that lock until destruction. The intention is to instantiate one of |
| 22 | /// these on the stack at the top of some scope to be assured that C++ |
| 23 | /// destruction of the object will always release the Mutex and thus avoid |
| 24 | /// a host of nasty multi-threading problems in the face of exceptions, etc. |
| 25 | /// Guard a section of code with a Mutex. |
| 26 | class MutexGuard { |
| 27 | sys::Mutex &M; |
| 28 | MutexGuard(const MutexGuard &) = delete; |
| 29 | void operator=(const MutexGuard &) = delete; |
| 30 | public: |
| 31 | MutexGuard(sys::Mutex &m) : M(m) { M.lock(); } |
| 32 | ~MutexGuard() { M.unlock(); } |
| 33 | /// holds - Returns true if this locker instance holds the specified lock. |
| 34 | /// This is mostly used in assertions to validate that the correct mutex |
| 35 | /// is held. |
| 36 | bool holds(const sys::Mutex& lock) const { return &M == &lock; } |
| 37 | }; |
| 38 | } |
| 39 | |
| 40 | #endif // LLVM_SUPPORT_MUTEXGUARD_H |