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Diffstat (limited to 'include/asterisk/named_locks.h')
| -rw-r--r-- | include/asterisk/named_locks.h | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/include/asterisk/named_locks.h b/include/asterisk/named_locks.h new file mode 100644 index 000000000..0fe07d992 --- /dev/null +++ b/include/asterisk/named_locks.h @@ -0,0 +1,105 @@ +/* + * Asterisk -- An open source telephony toolkit. + * + * Copyright (C) 2016, Fairview 5 Engineering, LLC + * + * George Joseph <george.joseph@fairview5.com> + * + * See http://www.asterisk.org for more information about + * the Asterisk project. Please do not directly contact + * any of the maintainers of this project for assistance; + * the project provides a web site, mailing lists and IRC + * channels for your use. + * + * This program is free software, distributed under the terms of + * the GNU General Public License Version 2. See the LICENSE file + * at the top of the source tree. + */ + +/*! \file + * + * \brief Named Locks + * + * \author George Joseph <george.joseph@fairview5.com> + */ + +#ifndef INCLUDE_ASTERISK_NAMED_LOCKS_H_ +#define INCLUDE_ASTERISK_NAMED_LOCKS_H_ + +#include "asterisk/astobj2.h" + +/*! + * \defgroup named_locks Named mutex and read-write locks + * @{ + * \page NamedLocks Named mutex and read-write locks + * \since 13.9.0 + * + * Locking some objects like sorcery objects can be tricky because the underlying + * ao2 object may not be the same for all callers. For instance, two threads that + * call ast_sorcery_retrieve_by_id on the same aor name might actually get 2 different + * ao2 objects if the underlying wizard had to rehydrate the aor from a database. + * Locking one ao2 object doesn't have any effect on the other even if those objects + * had locks in the first place + * + * Named locks allow access control by name. Now an aor named "1000" can be locked and + * any other thread attempting to lock the aor named "1000" will wait regardless of whether + * the underlying ao2 object is the same or not. + * + * To use a named lock: + * Call ast_named_lock_get with the appropriate keyspace and key. + * Use the standard ao2 lock/unlock functions as needed. + * Call ast_named_lock_put when you're finished with it. + */ + +/*! + * \brief Which type of lock to request. + */ +enum ast_named_lock_type { + /*! Request a named mutex. */ + AST_NAMED_LOCK_TYPE_MUTEX = AO2_ALLOC_OPT_LOCK_MUTEX, + /*! Request a named read/write lock. */ + AST_NAMED_LOCK_TYPE_RWLOCK = AO2_ALLOC_OPT_LOCK_RWLOCK, +}; + +struct ast_named_lock; + +struct ast_named_lock *__ast_named_lock_get(const char *filename, int lineno, const char *func, + enum ast_named_lock_type lock_type, const char *keyspace, const char *key); + +int __ast_named_lock_put(const char *filename, int lineno, const char *func, + struct ast_named_lock *lock); + +/*! + * \brief Geta named lock handle + * \since 13.9.0 + * + * \param lock_type One of ast_named_lock_type + * \param keyspace + * \param key + * \retval A pointer to an ast_named_lock structure + * \retval NULL on error + * + * \note + * keyspace and key can be anything. For sorcery objects, keyspace could be the object type + * and key could be the object id. + */ +#define ast_named_lock_get(lock_type, keyspace, key) \ + __ast_named_lock_get(__FILE__, __LINE__, __PRETTY_FUNCTION__, lock_type, \ + keyspace, key) + +/*! + * \brief Put a named lock handle away + * \since 13.9.0 + * + * \param lock The pointer to the ast_named_lock structure returned by ast_named_lock_get + * \retval 0 Success + * \retval -1 Failure + */ +#define ast_named_lock_put(lock) \ + __ast_named_lock_put(__FILE__, __LINE__, __PRETTY_FUNCTION__, lock) + +/*! + * @} + */ + +#endif /* INCLUDE_ASTERISK_NAMED_LOCKS_H_ */ |