A taskprocessor is an object that has a name, a task queue, and an event processing thread. Modules reference a taskprocessor, push tasks into the taskprocessor as needed, and unreference the taskprocessor when the taskprocessor is no longer needed.

A task wraps a callback function pointer and a data pointer and is managed internal to the taskprocessor subsystem.  The callback function is responsible for releasing task data.

Taskprocessor API
 * ast_taskprocessor_get(..) - returns a reference to a taskprocessor
 * ast_taskprocessor_unreference(..) - releases reference to a taskprocessor
 * ast_taskprocessor_push(..) - push a task into a taskprocessor queue

Check doxygen for more details


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@115268 65c4cc65-6c06-0410-ace0-fbb531ad65f3

include/asterisk/_private.h

@@ -36,6 +36,7 @@ int ast_features_init(void);            /*!< Provided by features.c */
 void ast_autoservice_init(void);	/*!< Provided by autoservice.c */
 int ast_http_init(void);		/*!< Provided by http.c */
 int ast_http_reload(void);		/*!< Provided by http.c */
+int ast_tps_init(void); 		/*!< Provided by taskprocessor.c */
 
 /*!
  * \brief Reload asterisk modules.

include/asterisk/taskprocessor.h

@@ -0,0 +1,94 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2007-2008, Dwayne M. Hubbard 
+ *
+ * Dwayne M. Hubbard <dhubbard@digium.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.
+ */
+#include "asterisk.h"
+#include "asterisk/lock.h"
+#include "asterisk/linkedlists.h"
+#include "asterisk/utils.h"
+#include "asterisk/options.h"
+
+#ifndef __taskprocessor_h__
+#define __taskprocessor_h__
+
+/*!
+ * \file taskprocessor.h
+ * \brief An API for managing task processing threads that can be shared across modules
+ *
+ * \author Dwayne M. Hubbard <dhubbard@digium.com>
+ *
+ * \note A taskprocessor is a named singleton containing a processing thread and
+ * a task queue that serializes tasks pushed into it by [a] module(s) that reference the taskprocessor.  
+ * A taskprocessor is created the first time its name is requested via the ast_taskprocessor_get()
+ * function and destroyed when the taskprocessor reference count reaches zero.
+ *
+ * Modules that obtain a reference to a taskprocessor can queue tasks into the taskprocessor
+ * to be processed by the singleton processing thread when the task is popped off the front 
+ * of the queue.  A task is a wrapper around a task-handling function pointer and a data
+ * pointer.  It is the responsibility of the task handling function to free memory allocated for
+ * the task data pointer.  A task is pushed into a taskprocessor queue using the 
+ * ast_taskprocessor_push(taskprocessor, taskhandler, taskdata) function and freed by the
+ * taskprocessor after the task handling function returns.  A module releases its reference to a
+ * taskprocessor using the ast_taskprocessor_unreference() function which may result in the
+ * destruction of the taskprocessor if the taskprocessor's reference count reaches zero.  Tasks waiting
+ * to be processed in the taskprocessor queue when the taskprocessor reference count reaches zero
+ * will be purged and released from the taskprocessor queue without being processed.
+ */
+struct ast_taskprocessor;
+
+/*! \brief ast_tps_options for specification of taskprocessor options
+ *
+ * Specify whether a taskprocessor should be created via ast_taskprocessor_get() if the taskprocessor 
+ * does not already exist.  The default behavior is to create a taskprocessor if it does not already exist 
+ * and provide its reference to the calling function.  To only return a reference to a taskprocessor if 
+ * and only if it exists, use the TPS_REF_IF_EXISTS option in ast_taskprocessor_get(). */
+enum ast_tps_options {
+	/*! \brief return a reference to a taskprocessor, create one if it does not exist */
+	TPS_REF_DEFAULT = 0,
+	/*! \brief return a reference to a taskprocessor ONLY if it already exists */
+	TPS_REF_IF_EXISTS = (1 << 0),
+};
+
+/*! \brief Get a reference to a taskprocessor with the specified name and create the taskprocessor if necessary
+ *
+ * The default behavior of instantiating a taskprocessor if one does not already exist can be
+ * disabled by specifying the TPS_REF_IF_EXISTS ast_tps_options as the second argument to ast_taskprocessor_get().
+ * \param name The name of the taskprocessor
+ * \param create Use 0 by default or specify TPS_REF_IF_EXISTS to return NULL if the taskprocessor does 
+ * not already exist
+ * return A pointer to a reference counted taskprocessor under normal conditions, or NULL if the
+ * TPS_REF_IF_EXISTS reference type is specified and the taskprocessor does not exist */
+struct ast_taskprocessor *ast_taskprocessor_get(char *name, enum ast_tps_options create);
+
+/*! \brief Unreference the specified taskprocessor and its reference count will decrement.
+ *
+ * Taskprocessors use astobj2 and will unlink from the taskprocessor singleton container and destroy
+ * themself when the taskprocessor reference count reaches zero.
+ * \param tps taskprocessor to unreference
+ * \return NULL */
+void *ast_taskprocessor_unreference(struct ast_taskprocessor *tps);
+
+/*! \brief Push a task into the specified taskprocessor queue and signal the taskprocessor thread
+ * \param tps The taskprocessor structure
+ * \param task_exe The task handling function to push into the taskprocessor queue
+ * \param datap The data to be used by the task handling function
+ * \return zero on success, -1 on failure */
+int ast_taskprocessor_push(struct ast_taskprocessor *tps, int (*task_exe)(void *datap), void *datap);
+
+/*! \brief Return the name of the taskprocessor singleton */
+const char *ast_taskprocessor_name(struct ast_taskprocessor *tps);
+#endif
+