Mon Aug 31 12:30:46 2015

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

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Functions

struct 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

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 
) [read]

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 424 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, ast_taskprocessor::poll_cond, ast_taskprocessor::poll_thread, ast_taskprocessor::poll_thread_run, ast_taskprocessor::stats, ast_taskprocessor::taskprocessor_lock, 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().

00425 {
00426    struct ast_taskprocessor *p, tmp_tps = {
00427       .name = name,
00428    };
00429       
00430    if (ast_strlen_zero(name)) {
00431       ast_log(LOG_ERROR, "requesting a nameless taskprocessor!!!\n");
00432       return NULL;
00433    }
00434    ao2_lock(tps_singletons);
00435    p = ao2_find(tps_singletons, &tmp_tps, OBJ_POINTER);
00436    if (p) {
00437       ao2_unlock(tps_singletons);
00438       return p;
00439    }
00440    if (create & TPS_REF_IF_EXISTS) {
00441       /* calling function does not want a new taskprocessor to be created if it doesn't already exist */
00442       ao2_unlock(tps_singletons);
00443       return NULL;
00444    }
00445    /* create a new taskprocessor */
00446    if (!(p = ao2_alloc(sizeof(*p), tps_taskprocessor_destroy))) {
00447       ao2_unlock(tps_singletons);
00448       ast_log(LOG_WARNING, "failed to create taskprocessor '%s'\n", name);
00449       return NULL;
00450    }
00451 
00452    ast_cond_init(&p->poll_cond, NULL);
00453    ast_mutex_init(&p->taskprocessor_lock);
00454 
00455    if (!(p->stats = ast_calloc(1, sizeof(*p->stats)))) {
00456       ao2_unlock(tps_singletons);
00457       ast_log(LOG_WARNING, "failed to create taskprocessor stats for '%s'\n", name);
00458       ao2_ref(p, -1);
00459       return NULL;
00460    }
00461    if (!(p->name = ast_strdup(name))) {
00462       ao2_unlock(tps_singletons);
00463       ao2_ref(p, -1);
00464       return NULL;
00465    }
00466    p->poll_thread_run = 1;
00467    p->poll_thread = AST_PTHREADT_NULL;
00468    if (ast_pthread_create(&p->poll_thread, NULL, tps_processing_function, p) < 0) {
00469       ao2_unlock(tps_singletons);
00470       ast_log(LOG_ERROR, "Taskprocessor '%s' failed to create the processing thread.\n", p->name);
00471       ao2_ref(p, -1);
00472       return NULL;
00473    }
00474    if (!(ao2_link(tps_singletons, p))) {
00475       ao2_unlock(tps_singletons);
00476       ast_log(LOG_ERROR, "Failed to add taskprocessor '%s' to container\n", p->name);
00477       ao2_ref(p, -1);
00478       return NULL;
00479    }
00480    ao2_unlock(tps_singletons);
00481    return p;
00482 }

const char* ast_taskprocessor_name ( struct ast_taskprocessor tps  ) 

Return the name of the taskprocessor singleton.

Since:
1.6.1

Definition at line 412 of file taskprocessor.c.

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

00413 {
00414    if (!tps) {
00415       ast_log(LOG_ERROR, "no taskprocessor specified!\n");
00416       return NULL;
00417    }
00418    return tps->name;
00419 }

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 499 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().

00500 {
00501    struct tps_task *t;
00502 
00503    if (!tps || !task_exe) {
00504       ast_log(LOG_ERROR, "%s is missing!!\n", (tps) ? "task callback" : "taskprocessor");
00505       return -1;
00506    }
00507    if (!(t = tps_task_alloc(task_exe, datap))) {
00508       ast_log(LOG_ERROR, "failed to allocate task!  Can't push to '%s'\n", tps->name);
00509       return -1;
00510    }
00511    ast_mutex_lock(&tps->taskprocessor_lock);
00512    AST_LIST_INSERT_TAIL(&tps->tps_queue, t, list);
00513    tps->tps_queue_size++;
00514    ast_cond_signal(&tps->poll_cond);
00515    ast_mutex_unlock(&tps->taskprocessor_lock);
00516    return 0;
00517 }

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 485 of file taskprocessor.c.

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

Referenced by __unload_module(), cc_shutdown(), event_shutdown(), unload_module(), and unload_pbx().

00486 {
00487    if (tps) {
00488       ao2_lock(tps_singletons);
00489       ao2_unlink(tps_singletons, tps);
00490       if (ao2_ref(tps, -1) > 1) {
00491          ao2_link(tps_singletons, tps);
00492       }
00493       ao2_unlock(tps_singletons);
00494    }
00495    return NULL;
00496 }


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