Mon Oct 8 12:39:30 2012

Asterisk developer's documentation


taskprocessor.h File Reference

An API for managing task processing threads that can be shared across modules. More...

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Enumerations

enum  ast_tps_options { TPS_REF_DEFAULT = 0, TPS_REF_IF_EXISTS = (1 << 0) }
 ast_tps_options for specification of taskprocessor options More...

Functions

ast_taskprocessorast_taskprocessor_get (const char *name, enum ast_tps_options create)
 Get a reference to a taskprocessor with the specified name and create the taskprocessor if necessary.
const char * ast_taskprocessor_name (struct ast_taskprocessor *tps)
 Return the name of the taskprocessor singleton.
int ast_taskprocessor_push (struct ast_taskprocessor *tps, int(*task_exe)(void *datap), void *datap)
 Push a task into the specified taskprocessor queue and signal the taskprocessor thread.
void * ast_taskprocessor_unreference (struct ast_taskprocessor *tps)
 Unreference the specified taskprocessor and its reference count will decrement.


Detailed Description

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.

Definition in file taskprocessor.h.


Enumeration Type Documentation

enum ast_tps_options

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().

Enumerator:
TPS_REF_DEFAULT  return a reference to a taskprocessor, create one if it does not exist
TPS_REF_IF_EXISTS  return a reference to a taskprocessor ONLY if it already exists

Definition at line 56 of file taskprocessor.h.

00056                      {
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 };


Function Documentation

struct ast_taskprocessor* ast_taskprocessor_get ( const char *  name,
enum ast_tps_options  create 
)

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().

Parameters:
name The name of the taskprocessor
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
Since:
1.6.1

Definition at line 413 of file taskprocessor.c.

References ao2_alloc, ao2_find, ao2_link, ao2_lock, ao2_ref, ao2_unlock, ast_calloc, ast_cond_init, ast_log(), ast_mutex_init, ast_pthread_create, AST_PTHREADT_NULL, ast_strdup, ast_strlen_zero(), LOG_ERROR, LOG_WARNING, ast_taskprocessor::name, OBJ_POINTER, tps_processing_function(), TPS_REF_IF_EXISTS, tps_singletons, and tps_taskprocessor_destroy().

Referenced by ast_cc_init(), ast_event_init(), cli_tps_ping(), load_module(), load_objects(), and load_pbx().

00414 {
00415    struct ast_taskprocessor *p, tmp_tps = {
00416       .name = name,
00417    };
00418       
00419    if (ast_strlen_zero(name)) {
00420       ast_log(LOG_ERROR, "requesting a nameless taskprocessor!!!\n");
00421       return NULL;
00422    }
00423    ao2_lock(tps_singletons);
00424    p = ao2_find(tps_singletons, &tmp_tps, OBJ_POINTER);
00425    if (p) {
00426       ao2_unlock(tps_singletons);
00427       return p;
00428    }
00429    if (create & TPS_REF_IF_EXISTS) {
00430       /* calling function does not want a new taskprocessor to be created if it doesn't already exist */
00431       ao2_unlock(tps_singletons);
00432       return NULL;
00433    }
00434    /* create a new taskprocessor */
00435    if (!(p = ao2_alloc(sizeof(*p), tps_taskprocessor_destroy))) {
00436       ao2_unlock(tps_singletons);
00437       ast_log(LOG_WARNING, "failed to create taskprocessor '%s'\n", name);
00438       return NULL;
00439    }
00440 
00441    ast_cond_init(&p->poll_cond, NULL);
00442    ast_mutex_init(&p->taskprocessor_lock);
00443 
00444    if (!(p->stats = ast_calloc(1, sizeof(*p->stats)))) {
00445       ao2_unlock(tps_singletons);
00446       ast_log(LOG_WARNING, "failed to create taskprocessor stats for '%s'\n", name);
00447       ao2_ref(p, -1);
00448       return NULL;
00449    }
00450    if (!(p->name = ast_strdup(name))) {
00451       ao2_unlock(tps_singletons);
00452       ao2_ref(p, -1);
00453       return NULL;
00454    }
00455    p->poll_thread_run = 1;
00456    p->poll_thread = AST_PTHREADT_NULL;
00457    if (ast_pthread_create(&p->poll_thread, NULL, tps_processing_function, p) < 0) {
00458       ao2_unlock(tps_singletons);
00459       ast_log(LOG_ERROR, "Taskprocessor '%s' failed to create the processing thread.\n", p->name);
00460       ao2_ref(p, -1);
00461       return NULL;
00462    }
00463    if (!(ao2_link(tps_singletons, p))) {
00464       ao2_unlock(tps_singletons);
00465       ast_log(LOG_ERROR, "Failed to add taskprocessor '%s' to container\n", p->name);
00466       ao2_ref(p, -1);
00467       return NULL;
00468    }
00469    ao2_unlock(tps_singletons);
00470    return p;
00471 }

const char* ast_taskprocessor_name ( struct ast_taskprocessor tps  ) 

Return the name of the taskprocessor singleton.

Since:
1.6.1

Definition at line 401 of file taskprocessor.c.

References ast_log(), LOG_ERROR, and ast_taskprocessor::name.

00402 {
00403    if (!tps) {
00404       ast_log(LOG_ERROR, "no taskprocessor specified!\n");
00405       return NULL;
00406    }
00407    return tps->name;
00408 }

int ast_taskprocessor_push ( struct ast_taskprocessor tps,
int(*)(void *datap)  task_exe,
void *  datap 
)

Push a task into the specified taskprocessor queue and signal the taskprocessor thread.

Parameters:
tps The taskprocessor structure
task_exe The task handling function to push into the taskprocessor queue
datap The data to be used by the task handling function
Return values:
0 success
-1 failure
Since:
1.6.1

Definition at line 488 of file taskprocessor.c.

References ast_cond_signal, AST_LIST_INSERT_TAIL, ast_log(), ast_mutex_lock, ast_mutex_unlock, LOG_ERROR, ast_taskprocessor::name, ast_taskprocessor::poll_cond, ast_taskprocessor::taskprocessor_lock, ast_taskprocessor::tps_queue, ast_taskprocessor::tps_queue_size, and tps_task_alloc().

Referenced by ast_cc_agent_status_response(), ast_cc_monitor_failed(), ast_cc_monitor_party_b_free(), ast_cc_monitor_status_request(), ast_cc_monitor_stop_ringing(), ast_event_queue(), cc_request_state_change(), cli_tps_ping(), device_state_cb(), generic_agent_devstate_cb(), generic_monitor_devstate_cb(), handle_cc_status(), iax2_transmit(), mwi_sub_event_cb(), and mwi_unsub_event_cb().

00489 {
00490    struct tps_task *t;
00491 
00492    if (!tps || !task_exe) {
00493       ast_log(LOG_ERROR, "%s is missing!!\n", (tps) ? "task callback" : "taskprocessor");
00494       return -1;
00495    }
00496    if (!(t = tps_task_alloc(task_exe, datap))) {
00497       ast_log(LOG_ERROR, "failed to allocate task!  Can't push to '%s'\n", tps->name);
00498       return -1;
00499    }
00500    ast_mutex_lock(&tps->taskprocessor_lock);
00501    AST_LIST_INSERT_TAIL(&tps->tps_queue, t, list);
00502    tps->tps_queue_size++;
00503    ast_cond_signal(&tps->poll_cond);
00504    ast_mutex_unlock(&tps->taskprocessor_lock);
00505    return 0;
00506 }

void* ast_taskprocessor_unreference ( struct ast_taskprocessor tps  ) 

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.

Parameters:
tps taskprocessor to unreference
Returns:
NULL
Since:
1.6.1

Definition at line 474 of file taskprocessor.c.

References ao2_link, ao2_lock, ao2_ref, ao2_unlink, ao2_unlock, and tps_singletons.

Referenced by __unload_module(), and unload_module().

00475 {
00476    if (tps) {
00477       ao2_lock(tps_singletons);
00478       ao2_unlink(tps_singletons, tps);
00479       if (ao2_ref(tps, -1) > 1) {
00480          ao2_link(tps_singletons, tps);
00481       }
00482       ao2_unlock(tps_singletons);
00483    }
00484    return NULL;
00485 }


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