00001 /* 00002 * Asterisk -- An open source telephony toolkit. 00003 * 00004 * Copyright (C) 2007-2008, Digium, Inc. 00005 * 00006 * Dwayne M. Hubbard <dhubbard@digium.com> 00007 * 00008 * See http://www.asterisk.org for more information about 00009 * the Asterisk project. Please do not directly contact 00010 * any of the maintainers of this project for assistance; 00011 * the project provides a web site, mailing lists and IRC 00012 * channels for your use. 00013 * 00014 * This program is free software, distributed under the terms of 00015 * the GNU General Public License Version 2. See the LICENSE file 00016 * at the top of the source tree. 00017 */ 00018 00019 /*! 00020 * \file taskprocessor.h 00021 * \brief An API for managing task processing threads that can be shared across modules 00022 * 00023 * \author Dwayne M. Hubbard <dhubbard@digium.com> 00024 * 00025 * \note A taskprocessor is a named singleton containing a processing thread and 00026 * a task queue that serializes tasks pushed into it by [a] module(s) that reference the taskprocessor. 00027 * A taskprocessor is created the first time its name is requested via the ast_taskprocessor_get() 00028 * function and destroyed when the taskprocessor reference count reaches zero. 00029 * 00030 * Modules that obtain a reference to a taskprocessor can queue tasks into the taskprocessor 00031 * to be processed by the singleton processing thread when the task is popped off the front 00032 * of the queue. A task is a wrapper around a task-handling function pointer and a data 00033 * pointer. It is the responsibility of the task handling function to free memory allocated for 00034 * the task data pointer. A task is pushed into a taskprocessor queue using the 00035 * ast_taskprocessor_push(taskprocessor, taskhandler, taskdata) function and freed by the 00036 * taskprocessor after the task handling function returns. A module releases its reference to a 00037 * taskprocessor using the ast_taskprocessor_unreference() function which may result in the 00038 * destruction of the taskprocessor if the taskprocessor's reference count reaches zero. Tasks waiting 00039 * to be processed in the taskprocessor queue when the taskprocessor reference count reaches zero 00040 * will be purged and released from the taskprocessor queue without being processed. 00041 */ 00042 00043 #ifndef __AST_TASKPROCESSOR_H__ 00044 #define __AST_TASKPROCESSOR_H__ 00045 00046 struct ast_taskprocessor; 00047 00048 /*! 00049 * \brief ast_tps_options for specification of taskprocessor options 00050 * 00051 * Specify whether a taskprocessor should be created via ast_taskprocessor_get() if the taskprocessor 00052 * does not already exist. The default behavior is to create a taskprocessor if it does not already exist 00053 * and provide its reference to the calling function. To only return a reference to a taskprocessor if 00054 * and only if it exists, use the TPS_REF_IF_EXISTS option in ast_taskprocessor_get(). 00055 */ 00056 enum ast_tps_options { 00057 /*! \brief return a reference to a taskprocessor, create one if it does not exist */ 00058 TPS_REF_DEFAULT = 0, 00059 /*! \brief return a reference to a taskprocessor ONLY if it already exists */ 00060 TPS_REF_IF_EXISTS = (1 << 0), 00061 }; 00062 00063 /*! 00064 * \brief Get a reference to a taskprocessor with the specified name and create the taskprocessor if necessary 00065 * 00066 * The default behavior of instantiating a taskprocessor if one does not already exist can be 00067 * disabled by specifying the TPS_REF_IF_EXISTS ast_tps_options as the second argument to ast_taskprocessor_get(). 00068 * \param name The name of the taskprocessor 00069 * \param create Use 0 by default or specify TPS_REF_IF_EXISTS to return NULL if the taskprocessor does 00070 * not already exist 00071 * return A pointer to a reference counted taskprocessor under normal conditions, or NULL if the 00072 * TPS_REF_IF_EXISTS reference type is specified and the taskprocessor does not exist 00073 * \since 1.6.1 00074 */ 00075 struct ast_taskprocessor *ast_taskprocessor_get(const char *name, enum ast_tps_options create); 00076 00077 /*! 00078 * \brief Unreference the specified taskprocessor and its reference count will decrement. 00079 * 00080 * Taskprocessors use astobj2 and will unlink from the taskprocessor singleton container and destroy 00081 * themself when the taskprocessor reference count reaches zero. 00082 * \param tps taskprocessor to unreference 00083 * \return NULL 00084 * \since 1.6.1 00085 */ 00086 void *ast_taskprocessor_unreference(struct ast_taskprocessor *tps); 00087 00088 /*! 00089 * \brief Push a task into the specified taskprocessor queue and signal the taskprocessor thread 00090 * \param tps The taskprocessor structure 00091 * \param task_exe The task handling function to push into the taskprocessor queue 00092 * \param datap The data to be used by the task handling function 00093 * \retval 0 success 00094 * \retval -1 failure 00095 * \since 1.6.1 00096 */ 00097 int ast_taskprocessor_push(struct ast_taskprocessor *tps, int (*task_exe)(void *datap), void *datap); 00098 00099 /*! 00100 * \brief Return the name of the taskprocessor singleton 00101 * \since 1.6.1 00102 */ 00103 const char *ast_taskprocessor_name(struct ast_taskprocessor *tps); 00104 00105 #endif /* __AST_TASKPROCESSOR_H__ */