1 //===- Support/UniqueLock.h - Acquire/Release Mutex In Scope ----*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines a guard for a block of code that ensures a Mutex is locked
11 // upon construction and released upon destruction.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_SUPPORT_UNIQUE_LOCK_H
16 #define LLVM_SUPPORT_UNIQUE_LOCK_H
22 /// A pared-down imitation of std::unique_lock from C++11. Contrary to the
23 /// name, it's really more of a wrapper for a lock. It may or may not have
24 /// an associated mutex, which is guaranteed to be locked upon creation
25 /// and unlocked after destruction. unique_lock can also unlock the mutex
26 /// and re-lock it freely during its lifetime.
27 /// @brief Guard a section of code with a mutex.
28 template<typename MutexT>
34 unique_lock() = default;
35 explicit unique_lock(MutexT &m) : M(&m), locked(true) { M->lock(); }
36 unique_lock(const unique_lock &) = delete;
37 unique_lock &operator=(const unique_lock &) = delete;
39 void operator=(unique_lock &&o) {
48 ~unique_lock() { if (owns_lock()) M->unlock(); }
51 assert(!locked && "mutex already locked!");
52 assert(M && "no associated mutex!");
58 assert(locked && "unlocking a mutex that isn't locked!");
59 assert(M && "no associated mutex!");
64 bool owns_lock() { return locked; }
67 } // end namespace llvm
69 #endif // LLVM_SUPPORT_UNIQUE_LOCK_H