Elliott Hughes | 8daa092 | 2011-09-11 13:46:25 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2011 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #ifndef ART_SRC_MUTEX_H_ |
| 18 | #define ART_SRC_MUTEX_H_ |
| 19 | |
| 20 | #include <pthread.h> |
Brian Carlstrom | cd74c4b | 2012-01-23 13:21:00 -0800 | [diff] [blame] | 21 | #include <stdint.h> |
Elliott Hughes | ffb465f | 2012-03-01 18:46:05 -0800 | [diff] [blame] | 22 | |
| 23 | #include <iosfwd> |
Elliott Hughes | 8daa092 | 2011-09-11 13:46:25 -0700 | [diff] [blame] | 24 | #include <string> |
| 25 | |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame^] | 26 | #include "globals.h" |
Elliott Hughes | 3efb841 | 2012-03-16 16:09:38 -0700 | [diff] [blame] | 27 | #include "gtest/gtest.h" |
Elliott Hughes | 8daa092 | 2011-09-11 13:46:25 -0700 | [diff] [blame] | 28 | #include "logging.h" |
| 29 | #include "macros.h" |
| 30 | |
| 31 | namespace art { |
| 32 | |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame^] | 33 | class LOCKABLE Mutex; |
| 34 | class LOCKABLE ReaderWriterMutex; |
Elliott Hughes | ffb465f | 2012-03-01 18:46:05 -0800 | [diff] [blame] | 35 | |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame^] | 36 | // MutexLevel is used to impose a lock hierarchy [1] where acquisition of a Mutex at a higher or |
| 37 | // equal level to a lock a thread holds is invalid. The lock hierarchy achieves a cycle free |
| 38 | // partial ordering and thereby cause deadlock situations to fail checks. |
| 39 | // |
| 40 | // [1] http://www.drdobbs.com/parallel/use-lock-hierarchies-to-avoid-deadlock/204801163 |
| 41 | enum MutexLevel { |
| 42 | kLoggingLock = 0, |
| 43 | kUnexpectedSignalLock = 1, |
| 44 | kThreadSuspendCountLock = 2, |
| 45 | kAbortLock = 3, |
| 46 | kDefaultMutexLevel = 4, |
| 47 | kLoadLibraryLock = 5, |
| 48 | kClassLinkerClassesLock = 6, |
| 49 | kThreadListLock = 7, |
| 50 | kHeapBitmapLock = 8, |
| 51 | kZygoteCreationLock = 9, |
| 52 | kMonitorLock = 10, |
| 53 | kMutatorLock = 11, |
| 54 | kMaxMutexLevel = kMutatorLock, |
| 55 | }; |
| 56 | std::ostream& operator<<(std::ostream& os, const MutexLevel& rhs); |
| 57 | |
| 58 | // Global mutexes corresponding to the levels above. |
| 59 | class GlobalSynchronization { |
Elliott Hughes | 8daa092 | 2011-09-11 13:46:25 -0700 | [diff] [blame] | 60 | public: |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame^] | 61 | static void Init(); |
| 62 | |
| 63 | // The mutator_lock_ is used to allow mutators to execute in a shared (reader) mode or to block |
| 64 | // mutators by having an exclusive (writer) owner. In normal execution each mutator thread holds |
| 65 | // a share on the mutator_lock_. The garbage collector may also execute with shared access but |
| 66 | // at times requires exclusive access to the heap (not to be confused with the heap meta-data |
| 67 | // guarded by the heap_lock_ below). When the garbage collector requires exclusive access it asks |
| 68 | // the mutators to suspend themselves which also involves usage of the thread_suspend_count_lock_ |
| 69 | // to cover weaknesses in using ReaderWriterMutexes with ConditionVariables. We use a condition |
| 70 | // variable to wait upon in the suspension logic as releasing and then re-acquiring a share on |
| 71 | // the mutator lock doesn't necessarily allow the exclusive user (e.g the garbage collector) |
| 72 | // chance to acquire the lock. |
| 73 | // |
| 74 | // Thread suspension: |
| 75 | // Shared users | Exclusive user |
| 76 | // (holding mutator lock and in kRunnable state) | .. running .. |
| 77 | // .. running .. | Request thread suspension by: |
| 78 | // .. running .. | - acquiring thread_suspend_count_lock_ |
| 79 | // .. running .. | - incrementing Thread::suspend_count_ on |
| 80 | // .. running .. | all mutator threads |
| 81 | // .. running .. | - releasing thread_suspend_count_lock_ |
| 82 | // .. running .. | Block trying to acquire exclusive mutator lock |
| 83 | // Poll Thread::suspend_count_ and enter full | .. blocked .. |
| 84 | // suspend code. | .. blocked .. |
| 85 | // Change state to kSuspended | .. blocked .. |
| 86 | // x: Release share on mutator_lock_ | Carry out exclusive access |
| 87 | // Acquire thread_suspend_count_lock_ | .. exclusive .. |
| 88 | // while Thread::suspend_count_ > 0 | .. exclusive .. |
| 89 | // - wait on Thread::resume_cond_ | .. exclusive .. |
| 90 | // (releases thread_suspend_count_lock_) | .. exclusive .. |
| 91 | // .. waiting .. | Release mutator_lock_ |
| 92 | // .. waiting .. | Request thread resumption by: |
| 93 | // .. waiting .. | - acquiring thread_suspend_count_lock_ |
| 94 | // .. waiting .. | - decrementing Thread::suspend_count_ on |
| 95 | // .. waiting .. | all mutator threads |
| 96 | // .. waiting .. | - notifying on Thread::resume_cond_ |
| 97 | // - re-acquire thread_suspend_count_lock_ | - releasing thread_suspend_count_lock_ |
| 98 | // Release thread_suspend_count_lock_ | .. running .. |
| 99 | // Acquire share on mutator_lock_ | .. running .. |
| 100 | // - This could block but the thread still | .. running .. |
| 101 | // has a state of kSuspended and so this | .. running .. |
| 102 | // isn't an issue. | .. running .. |
| 103 | // Acquire thread_suspend_count_lock_ | .. running .. |
| 104 | // - we poll here as we're transitioning into | .. running .. |
| 105 | // kRunnable and an individual thread suspend | .. running .. |
| 106 | // request (e.g for debugging) won't try | .. running .. |
| 107 | // to acquire the mutator lock (which would | .. running .. |
| 108 | // block as we hold the mutator lock). This | .. running .. |
| 109 | // poll ensures that if the suspender thought | .. running .. |
| 110 | // we were suspended by incrementing our | .. running .. |
| 111 | // Thread::suspend_count_ and then reading | .. running .. |
| 112 | // our state we go back to waiting on | .. running .. |
| 113 | // Thread::resume_cond_. | .. running .. |
| 114 | // can_go_runnable = Thread::suspend_count_ == 0 | .. running .. |
| 115 | // Release thread_suspend_count_lock_ | .. running .. |
| 116 | // if can_go_runnable | .. running .. |
| 117 | // Change state to kRunnable | .. running .. |
| 118 | // else | .. running .. |
| 119 | // Goto x | .. running .. |
| 120 | // .. running .. | .. running .. |
| 121 | static ReaderWriterMutex* mutator_lock_; |
| 122 | |
| 123 | // Allow reader-writer mutual exclusion on the mark and live bitmaps of the heap. |
| 124 | static ReaderWriterMutex* heap_bitmap_lock_ ACQUIRED_AFTER(mutator_lock_); |
| 125 | |
| 126 | // The thread_list_lock_ guards ThreadList::list_. It is also commonly held to stop threads |
| 127 | // attaching and detaching. |
| 128 | static Mutex* thread_list_lock_ ACQUIRED_AFTER(heap_bitmap_lock_); |
| 129 | |
| 130 | // Guards lists of classes within the class linker. |
| 131 | static Mutex* classlinker_classes_lock_ ACQUIRED_AFTER(thread_list_lock_); |
| 132 | |
| 133 | // When declaring any Mutex add DEFAULT_MUTEX_ACQUIRED_AFTER to use annotalysis to check the code |
| 134 | // doesn't try to hold a higher level Mutex. |
| 135 | #define DEFAULT_MUTEX_ACQUIRED_AFTER ACQUIRED_AFTER(classlinker_classes_lock_) |
| 136 | |
| 137 | // Have an exclusive aborting thread. |
| 138 | static Mutex* abort_lock_ ACQUIRED_AFTER(classlinker_classes_lock_); |
| 139 | |
| 140 | // Allow mutual exclusion when manipulating Thread::suspend_count_. |
| 141 | // TODO: Does the trade-off of a per-thread lock make sense? |
| 142 | static Mutex* thread_suspend_count_lock_ ACQUIRED_AFTER(abort_lock_); |
| 143 | |
| 144 | // One unexpected signal at a time lock. |
| 145 | static Mutex* unexpected_signal_lock_ ACQUIRED_AFTER(thread_suspend_count_lock_); |
| 146 | |
| 147 | // Have an exclusive logging thread. |
| 148 | static Mutex* logging_lock_ ACQUIRED_AFTER(unexpected_signal_lock_); |
| 149 | }; |
| 150 | |
| 151 | // Base class for all Mutex implementations |
| 152 | class BaseMutex { |
| 153 | public: |
| 154 | const std::string& GetName() const { |
| 155 | return name_; |
| 156 | } |
| 157 | |
| 158 | virtual bool IsMutex() const { return false; } |
| 159 | virtual bool IsReaderWriterMutex() const { return false; } |
| 160 | |
| 161 | protected: |
| 162 | friend class ConditionVariable; |
| 163 | |
| 164 | BaseMutex(const char* name, MutexLevel level); |
| 165 | virtual ~BaseMutex() {} |
| 166 | void RegisterAsLockedWithCurrentThread(); |
| 167 | void RegisterAsUnlockedWithCurrentThread(); |
| 168 | void CheckSafeToWait(); |
| 169 | |
| 170 | const MutexLevel level_; // Support for lock hierarchy. |
| 171 | const std::string name_; |
| 172 | }; |
| 173 | |
| 174 | // A Mutex is used to achieve mutual exclusion between threads. A Mutex can be used to gain |
| 175 | // exclusive access to what it guards. A Mutex can be in one of two states: |
| 176 | // - Free - not owned by any thread, |
| 177 | // - Exclusive - owned by a single thread. |
| 178 | // |
| 179 | // The effect of locking and unlocking operations on the state is: |
| 180 | // State | ExclusiveLock | ExclusiveUnlock |
| 181 | // ------------------------------------------- |
| 182 | // Free | Exclusive | error |
| 183 | // Exclusive | Block* | Free |
| 184 | // * Mutex is not reentrant and so an attempt to ExclusiveLock on the same thread will result in |
| 185 | // an error. Being non-reentrant simplifies Waiting on ConditionVariables. |
| 186 | class LOCKABLE Mutex : public BaseMutex { |
| 187 | public: |
| 188 | explicit Mutex(const char* name, MutexLevel level = kDefaultMutexLevel, bool recursive = false); |
Elliott Hughes | 8daa092 | 2011-09-11 13:46:25 -0700 | [diff] [blame] | 189 | ~Mutex(); |
| 190 | |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame^] | 191 | virtual bool IsMutex() const { return true; } |
Elliott Hughes | 8daa092 | 2011-09-11 13:46:25 -0700 | [diff] [blame] | 192 | |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame^] | 193 | // Block until mutex is free then acquire exclusive access. |
| 194 | void ExclusiveLock() EXCLUSIVE_LOCK_FUNCTION(); |
| 195 | void Lock() EXCLUSIVE_LOCK_FUNCTION() { ExclusiveLock(); } |
Elliott Hughes | 8daa092 | 2011-09-11 13:46:25 -0700 | [diff] [blame] | 196 | |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame^] | 197 | // Returns true if acquires exclusive access, false otherwise. |
| 198 | bool ExclusiveTryLock() EXCLUSIVE_TRYLOCK_FUNCTION(true); |
| 199 | bool TryLock() EXCLUSIVE_TRYLOCK_FUNCTION(true) { return ExclusiveTryLock(); } |
Elliott Hughes | 8daa092 | 2011-09-11 13:46:25 -0700 | [diff] [blame] | 200 | |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame^] | 201 | // Release exclusive access. |
| 202 | void ExclusiveUnlock() UNLOCK_FUNCTION(); |
| 203 | void Unlock() UNLOCK_FUNCTION() { ExclusiveUnlock(); } |
Elliott Hughes | 8daa092 | 2011-09-11 13:46:25 -0700 | [diff] [blame] | 204 | |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame^] | 205 | // Is the current thread the exclusive holder of the Mutex. |
| 206 | bool IsExclusiveHeld() const; |
| 207 | |
| 208 | // Assert that the Mutex is exclusively held by the current thread. |
| 209 | void AssertExclusiveHeld() { |
| 210 | if (kIsDebugBuild) { |
| 211 | CHECK(IsExclusiveHeld()); |
| 212 | } |
| 213 | } |
| 214 | void AssertHeld() { AssertExclusiveHeld(); } |
| 215 | |
| 216 | // Assert that the Mutex is not held by the current thread. |
| 217 | void AssertNotHeldExclusive() { |
| 218 | if (kIsDebugBuild) { |
| 219 | CHECK(!IsExclusiveHeld()); |
| 220 | } |
| 221 | } |
| 222 | void AssertNotHeld() { AssertNotHeldExclusive(); } |
| 223 | |
| 224 | // Id associated with exclusive owner. |
| 225 | uint64_t GetExclusiveOwnerTid() const; |
| 226 | |
| 227 | // Returns how many times this Mutex has been locked, it is better to use AssertHeld/NotHeld. |
| 228 | unsigned int GetDepth() const { |
| 229 | return recursion_count_; |
| 230 | } |
Elliott Hughes | accd83d | 2011-10-17 14:25:58 -0700 | [diff] [blame] | 231 | |
| 232 | private: |
Elliott Hughes | 8daa092 | 2011-09-11 13:46:25 -0700 | [diff] [blame] | 233 | pthread_mutex_t mutex_; |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame^] | 234 | const bool recursive_; // Can the lock be recursively held? |
| 235 | unsigned int recursion_count_; |
Elliott Hughes | f149843 | 2012-03-28 19:34:27 -0700 | [diff] [blame] | 236 | friend class ConditionVariable; |
Elliott Hughes | 3efb841 | 2012-03-16 16:09:38 -0700 | [diff] [blame] | 237 | friend class MutexTester; |
Elliott Hughes | 8daa092 | 2011-09-11 13:46:25 -0700 | [diff] [blame] | 238 | DISALLOW_COPY_AND_ASSIGN(Mutex); |
| 239 | }; |
| 240 | |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame^] | 241 | // A ReaderWriterMutex is used to achieve mutual exclusion between threads, similar to a Mutex. |
| 242 | // Unlike a Mutex a ReaderWriterMutex can be used to gain exclusive (writer) or shared (reader) |
| 243 | // access to what it guards. A flaw in relation to a Mutex is that it cannot be used with a |
| 244 | // condition variable. A ReaderWriterMutex can be in one of three states: |
| 245 | // - Free - not owned by any thread, |
| 246 | // - Exclusive - owned by a single thread, |
| 247 | // - Shared(n) - shared amongst n threads. |
| 248 | // |
| 249 | // The effect of locking and unlocking operations on the state is: |
| 250 | // |
| 251 | // State | ExclusiveLock | ExclusiveUnlock | SharedLock | SharedUnlock |
| 252 | // ---------------------------------------------------------------------------- |
| 253 | // Free | Exclusive | error | SharedLock(1) | error |
| 254 | // Exclusive | Block | Free | Block | error |
| 255 | // Shared(n) | Block | error | SharedLock(n+1)* | Shared(n-1) or Free |
| 256 | // * for large values of n the SharedLock may block. |
| 257 | class LOCKABLE ReaderWriterMutex : public BaseMutex { |
Elliott Hughes | 8daa092 | 2011-09-11 13:46:25 -0700 | [diff] [blame] | 258 | public: |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame^] | 259 | explicit ReaderWriterMutex(const char* name, MutexLevel level = kDefaultMutexLevel); |
| 260 | ~ReaderWriterMutex(); |
| 261 | |
| 262 | virtual bool IsReaderWriterMutex() const { return true; } |
| 263 | |
| 264 | // Block until ReaderWriterMutex is free then acquire exclusive access. |
| 265 | void ExclusiveLock() EXCLUSIVE_LOCK_FUNCTION(); |
| 266 | void WriterLock() EXCLUSIVE_LOCK_FUNCTION() { ExclusiveLock(); } |
| 267 | |
| 268 | // Release exclusive access. |
| 269 | void ExclusiveUnlock() UNLOCK_FUNCTION(); |
| 270 | void WriterUnlock() UNLOCK_FUNCTION() { ExclusiveUnlock(); } |
| 271 | |
| 272 | // Block until ReaderWriterMutex is free and acquire exclusive access. Returns true on success |
| 273 | // or false if timeout is reached. |
| 274 | bool ExclusiveLockWithTimeout(const timespec& abs_timeout) EXCLUSIVE_TRYLOCK_FUNCTION(true); |
| 275 | |
| 276 | // Block until ReaderWriterMutex is shared or free then acquire a share on the access. |
| 277 | void SharedLock() SHARED_LOCK_FUNCTION(); |
| 278 | void ReaderLock() SHARED_LOCK_FUNCTION() { SharedLock(); } |
| 279 | |
| 280 | // Try to acquire share of ReaderWriterMutex. |
| 281 | bool SharedTryLock() EXCLUSIVE_TRYLOCK_FUNCTION(true); |
| 282 | |
| 283 | // Release a share of the access. |
| 284 | void SharedUnlock() UNLOCK_FUNCTION(); |
| 285 | void ReaderUnlock() UNLOCK_FUNCTION() { SharedUnlock(); } |
| 286 | |
| 287 | // Is the current thread the exclusive holder of the ReaderWriterMutex. |
| 288 | bool IsExclusiveHeld() const; |
| 289 | |
| 290 | // Assert the current thread has exclusive access to the ReaderWriterMutex. |
| 291 | void AssertExclusiveHeld() { |
| 292 | if (kIsDebugBuild) { |
| 293 | CHECK(IsExclusiveHeld()); |
| 294 | } |
| 295 | } |
| 296 | void AssertWriterHeld() { AssertExclusiveHeld(); } |
| 297 | |
| 298 | // Assert the current thread doesn't have exclusive access to the ReaderWriterMutex. |
| 299 | void AssertNotExclusiveHeld() { |
| 300 | if (kIsDebugBuild) { |
| 301 | CHECK(!IsExclusiveHeld()); |
| 302 | } |
| 303 | } |
| 304 | void AssertNotWriterHeld() { AssertNotExclusiveHeld(); } |
| 305 | |
| 306 | // Is the current thread a shared holder of the ReaderWriterMutex. |
| 307 | bool IsSharedHeld() const; |
| 308 | |
| 309 | // Assert the current thread has shared access to the ReaderWriterMutex. |
| 310 | void AssertSharedHeld() { |
| 311 | if (kIsDebugBuild) { |
| 312 | CHECK(IsSharedHeld()); |
| 313 | } |
| 314 | } |
| 315 | void AssertReaderHeld() { AssertSharedHeld(); } |
| 316 | |
| 317 | // Assert the current thread doesn't hold this ReaderWriterMutex either in shared or exclusive |
| 318 | // mode. |
| 319 | void AssertNotHeld() { |
| 320 | if (kIsDebugBuild) { |
| 321 | CHECK(!IsSharedHeld()); |
| 322 | } |
Elliott Hughes | 8daa092 | 2011-09-11 13:46:25 -0700 | [diff] [blame] | 323 | } |
| 324 | |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame^] | 325 | // Id associated with exclusive owner. |
| 326 | uint64_t GetExclusiveOwnerTid() const; |
Elliott Hughes | 8daa092 | 2011-09-11 13:46:25 -0700 | [diff] [blame] | 327 | private: |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame^] | 328 | pthread_rwlock_t rwlock_; |
Elliott Hughes | 8daa092 | 2011-09-11 13:46:25 -0700 | [diff] [blame] | 329 | |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame^] | 330 | friend class MutexTester; |
| 331 | DISALLOW_COPY_AND_ASSIGN(ReaderWriterMutex); |
| 332 | }; |
| 333 | |
| 334 | // ConditionVariables allow threads to queue and sleep. Threads may then be resumed individually |
| 335 | // (Signal) or all at once (Broadcast). |
Elliott Hughes | 5f79133 | 2011-09-15 17:45:30 -0700 | [diff] [blame] | 336 | class ConditionVariable { |
| 337 | public: |
Elliott Hughes | a51a3dd | 2011-10-17 15:19:26 -0700 | [diff] [blame] | 338 | explicit ConditionVariable(const std::string& name); |
Elliott Hughes | 5f79133 | 2011-09-15 17:45:30 -0700 | [diff] [blame] | 339 | ~ConditionVariable(); |
| 340 | |
| 341 | void Broadcast(); |
| 342 | void Signal(); |
| 343 | void Wait(Mutex& mutex); |
| 344 | void TimedWait(Mutex& mutex, const timespec& ts); |
| 345 | |
| 346 | private: |
| 347 | pthread_cond_t cond_; |
| 348 | std::string name_; |
| 349 | DISALLOW_COPY_AND_ASSIGN(ConditionVariable); |
| 350 | }; |
| 351 | |
Ian Rogers | 00f7d0e | 2012-07-19 15:28:27 -0700 | [diff] [blame^] | 352 | // Scoped locker/unlocker for a regular Mutex that acquires mu upon construction and releases it |
| 353 | // upon destruction. |
| 354 | class SCOPED_LOCKABLE MutexLock { |
| 355 | public: |
| 356 | explicit MutexLock(Mutex& mu) EXCLUSIVE_LOCK_FUNCTION(mu) : mu_(mu) { |
| 357 | mu_.ExclusiveLock(); |
| 358 | } |
| 359 | |
| 360 | ~MutexLock() UNLOCK_FUNCTION() { |
| 361 | mu_.ExclusiveUnlock(); |
| 362 | } |
| 363 | |
| 364 | private: |
| 365 | Mutex& mu_; |
| 366 | DISALLOW_COPY_AND_ASSIGN(MutexLock); |
| 367 | }; |
| 368 | // Catch bug where variable name is omitted. "MutexLock (lock);" instead of "MutexLock mu(lock)". |
| 369 | #define MutexLock(x) COMPILE_ASSERT(0, mutex_lock_declaration_missing_variable_name) |
| 370 | |
| 371 | // Scoped locker/unlocker for a ReaderWriterMutex that acquires read access to mu upon |
| 372 | // construction and releases it upon destruction. |
| 373 | class SCOPED_LOCKABLE ReaderMutexLock { |
| 374 | public: |
| 375 | explicit ReaderMutexLock(ReaderWriterMutex& mu) EXCLUSIVE_LOCK_FUNCTION(mu) : mu_(mu) { |
| 376 | mu_.SharedLock(); |
| 377 | } |
| 378 | |
| 379 | ~ReaderMutexLock() UNLOCK_FUNCTION() { |
| 380 | mu_.SharedUnlock(); |
| 381 | } |
| 382 | |
| 383 | private: |
| 384 | ReaderWriterMutex& mu_; |
| 385 | DISALLOW_COPY_AND_ASSIGN(ReaderMutexLock); |
| 386 | }; |
| 387 | // Catch bug where variable name is omitted. "ReaderMutexLock (lock);" instead of |
| 388 | // "ReaderMutexLock mu(lock)". |
| 389 | #define ReaderMutexLock(x) COMPILE_ASSERT(0, reader_mutex_lock_declaration_missing_variable_name) |
| 390 | |
| 391 | // Scoped locker/unlocker for a ReaderWriterMutex that acquires write access to mu upon |
| 392 | // construction and releases it upon destruction. |
| 393 | class SCOPED_LOCKABLE WriterMutexLock { |
| 394 | public: |
| 395 | explicit WriterMutexLock(ReaderWriterMutex& mu) EXCLUSIVE_LOCK_FUNCTION(mu) : mu_(mu) { |
| 396 | mu_.ExclusiveLock(); |
| 397 | } |
| 398 | |
| 399 | ~WriterMutexLock() UNLOCK_FUNCTION() { |
| 400 | mu_.ExclusiveUnlock(); |
| 401 | } |
| 402 | |
| 403 | private: |
| 404 | ReaderWriterMutex& mu_; |
| 405 | DISALLOW_COPY_AND_ASSIGN(WriterMutexLock); |
| 406 | }; |
| 407 | // Catch bug where variable name is omitted. "WriterMutexLock (lock);" instead of |
| 408 | // "WriterMutexLock mu(lock)". |
| 409 | #define WriterMutexLock(x) COMPILE_ASSERT(0, writer_mutex_lock_declaration_missing_variable_name) |
| 410 | |
| 411 | // Scoped unlocker/locker for a ReaderWriterMutex that releases read access to mu upon |
| 412 | // construction and acquires it again upon destruction. |
| 413 | class ReaderMutexUnlock { |
| 414 | public: |
| 415 | explicit ReaderMutexUnlock(ReaderWriterMutex& mu) UNLOCK_FUNCTION(mu) : mu_(mu) { |
| 416 | mu_.SharedUnlock(); |
| 417 | } |
| 418 | |
| 419 | ~ReaderMutexUnlock() SHARED_LOCK_FUNCTION(mu_) { |
| 420 | mu_.SharedLock(); |
| 421 | } |
| 422 | |
| 423 | private: |
| 424 | ReaderWriterMutex& mu_; |
| 425 | DISALLOW_COPY_AND_ASSIGN(ReaderMutexUnlock); |
| 426 | }; |
| 427 | // Catch bug where variable name is omitted. "ReaderMutexUnlock (lock);" instead of |
| 428 | // "ReaderMutexUnlock mu(lock)". |
| 429 | #define ReaderMutexUnlock(x) \ |
| 430 | COMPILE_ASSERT(0, reader_mutex_unlock_declaration_missing_variable_name) |
| 431 | |
Elliott Hughes | 8daa092 | 2011-09-11 13:46:25 -0700 | [diff] [blame] | 432 | } // namespace art |
| 433 | |
| 434 | #endif // ART_SRC_MUTEX_H_ |