Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1 | // Copyright 2013 the V8 project authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | #ifndef V8_BASE_PLATFORM_MUTEX_H_ |
| 6 | #define V8_BASE_PLATFORM_MUTEX_H_ |
| 7 | |
| 8 | #include "src/base/lazy-instance.h" |
| 9 | #if V8_OS_WIN |
| 10 | #include "src/base/win32-headers.h" |
| 11 | #endif |
| 12 | #include "src/base/logging.h" |
| 13 | |
| 14 | #if V8_OS_POSIX |
| 15 | #include <pthread.h> // NOLINT |
| 16 | #endif |
| 17 | |
| 18 | namespace v8 { |
| 19 | namespace base { |
| 20 | |
| 21 | // ---------------------------------------------------------------------------- |
| 22 | // Mutex |
| 23 | // |
| 24 | // This class is a synchronization primitive that can be used to protect shared |
| 25 | // data from being simultaneously accessed by multiple threads. A mutex offers |
| 26 | // exclusive, non-recursive ownership semantics: |
| 27 | // - A calling thread owns a mutex from the time that it successfully calls |
| 28 | // either |Lock()| or |TryLock()| until it calls |Unlock()|. |
| 29 | // - When a thread owns a mutex, all other threads will block (for calls to |
| 30 | // |Lock()|) or receive a |false| return value (for |TryLock()|) if they |
| 31 | // attempt to claim ownership of the mutex. |
| 32 | // A calling thread must not own the mutex prior to calling |Lock()| or |
| 33 | // |TryLock()|. The behavior of a program is undefined if a mutex is destroyed |
| 34 | // while still owned by some thread. The Mutex class is non-copyable. |
| 35 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 36 | class Mutex final { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 37 | public: |
| 38 | Mutex(); |
| 39 | ~Mutex(); |
| 40 | |
| 41 | // Locks the given mutex. If the mutex is currently unlocked, it becomes |
| 42 | // locked and owned by the calling thread, and immediately. If the mutex |
| 43 | // is already locked by another thread, suspends the calling thread until |
| 44 | // the mutex is unlocked. |
| 45 | void Lock(); |
| 46 | |
| 47 | // Unlocks the given mutex. The mutex is assumed to be locked and owned by |
| 48 | // the calling thread on entrance. |
| 49 | void Unlock(); |
| 50 | |
| 51 | // Tries to lock the given mutex. Returns whether the mutex was |
| 52 | // successfully locked. |
| 53 | bool TryLock() WARN_UNUSED_RESULT; |
| 54 | |
| 55 | // The implementation-defined native handle type. |
| 56 | #if V8_OS_POSIX |
| 57 | typedef pthread_mutex_t NativeHandle; |
| 58 | #elif V8_OS_WIN |
| 59 | typedef CRITICAL_SECTION NativeHandle; |
| 60 | #endif |
| 61 | |
| 62 | NativeHandle& native_handle() { |
| 63 | return native_handle_; |
| 64 | } |
| 65 | const NativeHandle& native_handle() const { |
| 66 | return native_handle_; |
| 67 | } |
| 68 | |
| 69 | private: |
| 70 | NativeHandle native_handle_; |
| 71 | #ifdef DEBUG |
| 72 | int level_; |
| 73 | #endif |
| 74 | |
| 75 | V8_INLINE void AssertHeldAndUnmark() { |
| 76 | #ifdef DEBUG |
| 77 | DCHECK_EQ(1, level_); |
| 78 | level_--; |
| 79 | #endif |
| 80 | } |
| 81 | |
| 82 | V8_INLINE void AssertUnheldAndMark() { |
| 83 | #ifdef DEBUG |
| 84 | DCHECK_EQ(0, level_); |
| 85 | level_++; |
| 86 | #endif |
| 87 | } |
| 88 | |
| 89 | friend class ConditionVariable; |
| 90 | |
| 91 | DISALLOW_COPY_AND_ASSIGN(Mutex); |
| 92 | }; |
| 93 | |
| 94 | |
| 95 | // POD Mutex initialized lazily (i.e. the first time Pointer() is called). |
| 96 | // Usage: |
| 97 | // static LazyMutex my_mutex = LAZY_MUTEX_INITIALIZER; |
| 98 | // |
| 99 | // void my_function() { |
| 100 | // LockGuard<Mutex> guard(my_mutex.Pointer()); |
| 101 | // // Do something. |
| 102 | // } |
| 103 | // |
| 104 | typedef LazyStaticInstance<Mutex, DefaultConstructTrait<Mutex>, |
| 105 | ThreadSafeInitOnceTrait>::type LazyMutex; |
| 106 | |
| 107 | #define LAZY_MUTEX_INITIALIZER LAZY_STATIC_INSTANCE_INITIALIZER |
| 108 | |
| 109 | |
| 110 | // ----------------------------------------------------------------------------- |
| 111 | // RecursiveMutex |
| 112 | // |
| 113 | // This class is a synchronization primitive that can be used to protect shared |
| 114 | // data from being simultaneously accessed by multiple threads. A recursive |
| 115 | // mutex offers exclusive, recursive ownership semantics: |
| 116 | // - A calling thread owns a recursive mutex for a period of time that starts |
| 117 | // when it successfully calls either |Lock()| or |TryLock()|. During this |
| 118 | // period, the thread may make additional calls to |Lock()| or |TryLock()|. |
| 119 | // The period of ownership ends when the thread makes a matching number of |
| 120 | // calls to |Unlock()|. |
| 121 | // - When a thread owns a recursive mutex, all other threads will block (for |
| 122 | // calls to |Lock()|) or receive a |false| return value (for |TryLock()|) if |
| 123 | // they attempt to claim ownership of the recursive mutex. |
| 124 | // - The maximum number of times that a recursive mutex may be locked is |
| 125 | // unspecified, but after that number is reached, calls to |Lock()| will |
| 126 | // probably abort the process and calls to |TryLock()| return false. |
| 127 | // The behavior of a program is undefined if a recursive mutex is destroyed |
| 128 | // while still owned by some thread. The RecursiveMutex class is non-copyable. |
| 129 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 130 | class RecursiveMutex final { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 131 | public: |
| 132 | RecursiveMutex(); |
| 133 | ~RecursiveMutex(); |
| 134 | |
| 135 | // Locks the mutex. If another thread has already locked the mutex, a call to |
| 136 | // |Lock()| will block execution until the lock is acquired. A thread may call |
| 137 | // |Lock()| on a recursive mutex repeatedly. Ownership will only be released |
| 138 | // after the thread makes a matching number of calls to |Unlock()|. |
| 139 | // The behavior is undefined if the mutex is not unlocked before being |
| 140 | // destroyed, i.e. some thread still owns it. |
| 141 | void Lock(); |
| 142 | |
| 143 | // Unlocks the mutex if its level of ownership is 1 (there was exactly one |
| 144 | // more call to |Lock()| than there were calls to unlock() made by this |
| 145 | // thread), reduces the level of ownership by 1 otherwise. The mutex must be |
| 146 | // locked by the current thread of execution, otherwise, the behavior is |
| 147 | // undefined. |
| 148 | void Unlock(); |
| 149 | |
| 150 | // Tries to lock the given mutex. Returns whether the mutex was |
| 151 | // successfully locked. |
| 152 | bool TryLock() WARN_UNUSED_RESULT; |
| 153 | |
| 154 | // The implementation-defined native handle type. |
| 155 | typedef Mutex::NativeHandle NativeHandle; |
| 156 | |
| 157 | NativeHandle& native_handle() { |
| 158 | return native_handle_; |
| 159 | } |
| 160 | const NativeHandle& native_handle() const { |
| 161 | return native_handle_; |
| 162 | } |
| 163 | |
| 164 | private: |
| 165 | NativeHandle native_handle_; |
| 166 | #ifdef DEBUG |
| 167 | int level_; |
| 168 | #endif |
| 169 | |
| 170 | DISALLOW_COPY_AND_ASSIGN(RecursiveMutex); |
| 171 | }; |
| 172 | |
| 173 | |
| 174 | // POD RecursiveMutex initialized lazily (i.e. the first time Pointer() is |
| 175 | // called). |
| 176 | // Usage: |
| 177 | // static LazyRecursiveMutex my_mutex = LAZY_RECURSIVE_MUTEX_INITIALIZER; |
| 178 | // |
| 179 | // void my_function() { |
| 180 | // LockGuard<RecursiveMutex> guard(my_mutex.Pointer()); |
| 181 | // // Do something. |
| 182 | // } |
| 183 | // |
| 184 | typedef LazyStaticInstance<RecursiveMutex, |
| 185 | DefaultConstructTrait<RecursiveMutex>, |
| 186 | ThreadSafeInitOnceTrait>::type LazyRecursiveMutex; |
| 187 | |
| 188 | #define LAZY_RECURSIVE_MUTEX_INITIALIZER LAZY_STATIC_INSTANCE_INITIALIZER |
| 189 | |
| 190 | |
| 191 | // ----------------------------------------------------------------------------- |
| 192 | // LockGuard |
| 193 | // |
| 194 | // This class is a mutex wrapper that provides a convenient RAII-style mechanism |
| 195 | // for owning a mutex for the duration of a scoped block. |
| 196 | // When a LockGuard object is created, it attempts to take ownership of the |
| 197 | // mutex it is given. When control leaves the scope in which the LockGuard |
| 198 | // object was created, the LockGuard is destructed and the mutex is released. |
| 199 | // The LockGuard class is non-copyable. |
| 200 | |
| 201 | template <typename Mutex> |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 202 | class LockGuard final { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 203 | public: |
| 204 | explicit LockGuard(Mutex* mutex) : mutex_(mutex) { mutex_->Lock(); } |
| 205 | ~LockGuard() { mutex_->Unlock(); } |
| 206 | |
| 207 | private: |
| 208 | Mutex* mutex_; |
| 209 | |
| 210 | DISALLOW_COPY_AND_ASSIGN(LockGuard); |
| 211 | }; |
| 212 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 213 | } // namespace base |
| 214 | } // namespace v8 |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 215 | |
| 216 | #endif // V8_BASE_PLATFORM_MUTEX_H_ |