//////////////////////////////////////////////////////////////////////////////// /// DISCLAIMER /// /// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany /// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany /// /// Licensed under the Apache License, Version 2.0 (the "License"); /// you may not use this file except in compliance with the License. /// You may obtain a copy of the License at /// /// http://www.apache.org/licenses/LICENSE-2.0 /// /// Unless required by applicable law or agreed to in writing, software /// distributed under the License is distributed on an "AS IS" BASIS, /// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. /// See the License for the specific language governing permissions and /// limitations under the License. /// /// Copyright holder is ArangoDB GmbH, Cologne, Germany /// /// @author Dr. Frank Celler //////////////////////////////////////////////////////////////////////////////// #ifndef ARANGODB_BASICS_LOCKS_H #define ARANGODB_BASICS_LOCKS_H 1 #include "Basics/Common.h" #ifdef TRI_HAVE_POSIX_THREADS #include "Basics/locks-posix.h" #endif #ifdef TRI_HAVE_WIN32_THREADS #include "Basics/locks-win32.h" #endif //////////////////////////////////////////////////////////////////////////////// /// @brief initializes a new mutex /// /// Mutual exclusion (often abbreviated to mutex) algorithms are used in /// concurrent programming to avoid the simultaneous use of a common resource, /// such as a global variable, by pieces of computer code called critical /// sections. A critical section is a piece of code in which a process or thread /// accesses a common resource. The critical section by itself is not a /// mechanism or algorithm for mutual exclusion. A program, process, or thread /// can have the critical section in it without any mechanism or algorithm which /// implements mutual exclusion. For details see www.wikipedia.org. //////////////////////////////////////////////////////////////////////////////// int TRI_InitMutex(TRI_mutex_t*); //////////////////////////////////////////////////////////////////////////////// /// @brief destroys a mutex //////////////////////////////////////////////////////////////////////////////// int TRI_DestroyMutex(TRI_mutex_t*); //////////////////////////////////////////////////////////////////////////////// /// @brief locks mutex //////////////////////////////////////////////////////////////////////////////// void TRI_LockMutex(TRI_mutex_t*); //////////////////////////////////////////////////////////////////////////////// /// @brief unlocks mutex //////////////////////////////////////////////////////////////////////////////// void TRI_UnlockMutex(TRI_mutex_t*); //////////////////////////////////////////////////////////////////////////////// /// @brief initializes a new read-write lock /// /// A ReadWriteLock maintains a pair of associated locks, one for read-only /// operations and one for writing. The read lock may be held simultaneously by /// multiple reader threads, so long as there are no writers. The write lock is /// exclusive. /// /// A read-write lock allows for a greater level of concurrency in accessing /// shared data than that permitted by a mutual exclusion lock. It exploits the /// fact that while only a single thread at a time (a writer thread) can modify /// the shared data, in many cases any number of threads can concurrently read /// the data (hence reader threads). In theory, the increase in concurrency /// permitted by the use of a read-write lock will lead to performance /// improvements over the use of a mutual exclusion lock. In practice this /// increase in concurrency will only be fully realized on a multi-processor, /// and then only if the access patterns for the shared data are suitable. //////////////////////////////////////////////////////////////////////////////// void TRI_InitReadWriteLock(TRI_read_write_lock_t* lock); //////////////////////////////////////////////////////////////////////////////// /// @brief destroyes a read-write lock //////////////////////////////////////////////////////////////////////////////// void TRI_DestroyReadWriteLock(TRI_read_write_lock_t* lock); //////////////////////////////////////////////////////////////////////////////// /// @brief tries to read lock read-write lock //////////////////////////////////////////////////////////////////////////////// bool TRI_TryReadLockReadWriteLock(TRI_read_write_lock_t* lock); //////////////////////////////////////////////////////////////////////////////// /// @brief read locks read-write lock //////////////////////////////////////////////////////////////////////////////// void TRI_ReadLockReadWriteLock(TRI_read_write_lock_t* lock); //////////////////////////////////////////////////////////////////////////////// /// @brief read unlocks read-write lock //////////////////////////////////////////////////////////////////////////////// void TRI_ReadUnlockReadWriteLock(TRI_read_write_lock_t* lock); //////////////////////////////////////////////////////////////////////////////// /// @brief tries to write lock read-write lock //////////////////////////////////////////////////////////////////////////////// bool TRI_TryWriteLockReadWriteLock(TRI_read_write_lock_t* lock); //////////////////////////////////////////////////////////////////////////////// /// @brief write locks read-write lock //////////////////////////////////////////////////////////////////////////////// void TRI_WriteLockReadWriteLock(TRI_read_write_lock_t* lock); //////////////////////////////////////////////////////////////////////////////// /// @brief write unlocks read-write lock //////////////////////////////////////////////////////////////////////////////// void TRI_WriteUnlockReadWriteLock(TRI_read_write_lock_t* lock); //////////////////////////////////////////////////////////////////////////////// /// @brief initializes a new condition variable //////////////////////////////////////////////////////////////////////////////// void TRI_InitCondition(TRI_condition_t* cond); //////////////////////////////////////////////////////////////////////////////// /// @brief destroys a condition variable //////////////////////////////////////////////////////////////////////////////// void TRI_DestroyCondition(TRI_condition_t* cond); //////////////////////////////////////////////////////////////////////////////// /// @brief signals a condition variable /// /// Note that you must hold the lock. //////////////////////////////////////////////////////////////////////////////// void TRI_SignalCondition(TRI_condition_t* cond); //////////////////////////////////////////////////////////////////////////////// /// @brief broad casts a condition variable /// /// Note that you must hold the lock. //////////////////////////////////////////////////////////////////////////////// void TRI_BroadcastCondition(TRI_condition_t* cond); //////////////////////////////////////////////////////////////////////////////// /// @brief waits for a signal on a condition variable /// /// Note that you must hold the lock. //////////////////////////////////////////////////////////////////////////////// void TRI_WaitCondition(TRI_condition_t* cond); //////////////////////////////////////////////////////////////////////////////// /// @brief waits for a signal with a timeout in micro-seconds /// /// Note that you must hold the lock. //////////////////////////////////////////////////////////////////////////////// bool TRI_TimedWaitCondition(TRI_condition_t* cond, uint64_t delay); //////////////////////////////////////////////////////////////////////////////// /// @brief locks the mutex of a condition variable //////////////////////////////////////////////////////////////////////////////// void TRI_LockCondition(TRI_condition_t* cond); //////////////////////////////////////////////////////////////////////////////// /// @brief unlocks the mutex of a condition variable //////////////////////////////////////////////////////////////////////////////// void TRI_UnlockCondition(TRI_condition_t* cond); #endif