Asterisk - The Open Source Telephony Project  GIT-master-09303e8
taskprocessor.h
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1 /*
2  * Asterisk -- An open source telephony toolkit.
3  *
4  * Copyright (C) 2007-2013, Digium, Inc.
5  *
6  * Dwayne M. Hubbard <dhubbard@digium.com>
7  *
8  * See http://www.asterisk.org for more information about
9  * the Asterisk project. Please do not directly contact
10  * any of the maintainers of this project for assistance;
11  * the project provides a web site, mailing lists and IRC
12  * channels for your use.
13  *
14  * This program is free software, distributed under the terms of
15  * the GNU General Public License Version 2. See the LICENSE file
16  * at the top of the source tree.
17  */
18 
19 /*!
20  * \file taskprocessor.h
21  * \brief An API for managing task processing threads that can be shared across modules
22  *
23  * \author Dwayne M. Hubbard <dhubbard@digium.com>
24  *
25  * \note A taskprocessor is a named object containing a task queue that
26  * serializes tasks pushed into it by [a] module(s) that reference the taskprocessor.
27  * A taskprocessor is created the first time its name is requested via the
28  * ast_taskprocessor_get() function or the ast_taskprocessor_create_with_listener()
29  * function and destroyed when the taskprocessor reference count reaches zero. A
30  * taskprocessor also contains an accompanying listener that is notified when changes
31  * in the task queue occur.
32  *
33  * A task is a wrapper around a task-handling function pointer and a data
34  * pointer. A task is pushed into a taskprocessor queue using the
35  * ast_taskprocessor_push(taskprocessor, taskhandler, taskdata) function and freed by the
36  * taskprocessor after the task handling function returns. A module releases its
37  * reference to a taskprocessor using the ast_taskprocessor_unreference() function which
38  * may result in the destruction of the taskprocessor if the taskprocessor's reference
39  * count reaches zero. When the taskprocessor's reference count reaches zero, its
40  * listener's shutdown() callback will be called. Any further attempts to execute tasks
41  * will be denied.
42  *
43  * The taskprocessor listener has the flexibility of doling out tasks to best fit the
44  * module's needs. For instance, a taskprocessor listener may have a single dispatch
45  * thread that handles all tasks, or it may dispatch tasks to a thread pool.
46  *
47  * There is a default taskprocessor listener that will be used if a taskprocessor is
48  * created without any explicit listener. This default listener runs tasks sequentially
49  * in a single thread. The listener will execute tasks as long as there are tasks to be
50  * processed. When the taskprocessor is shut down, the default listener will stop
51  * processing tasks and join its execution thread.
52  */
53 
54 #ifndef __AST_TASKPROCESSOR_H__
55 #define __AST_TASKPROCESSOR_H__
56 
57 struct ast_taskprocessor;
58 
59 /*! \brief Suggested maximum taskprocessor name length (less null terminator). */
60 #define AST_TASKPROCESSOR_MAX_NAME 70
61 
62 /*! Default taskprocessor high water level alert trigger */
63 #define AST_TASKPROCESSOR_HIGH_WATER_LEVEL 500
64 
65 /*!
66  * \brief ast_tps_options for specification of taskprocessor options
67  *
68  * Specify whether a taskprocessor should be created via ast_taskprocessor_get() if the taskprocessor
69  * does not already exist. The default behavior is to create a taskprocessor if it does not already exist
70  * and provide its reference to the calling function. To only return a reference to a taskprocessor if
71  * and only if it exists, use the TPS_REF_IF_EXISTS option in ast_taskprocessor_get().
72  */
74  /*! \brief return a reference to a taskprocessor, create one if it does not exist */
76  /*! \brief return a reference to a taskprocessor ONLY if it already exists */
77  TPS_REF_IF_EXISTS = (1 << 0),
78 };
79 
81 
83  /*!
84  * \brief The taskprocessor has started completely
85  *
86  * This indicates that the taskprocessor is fully set up and the listener
87  * can now start interacting with it.
88  *
89  * \param listener The listener to start
90  */
92  /*!
93  * \brief Indicates a task was pushed to the processor
94  *
95  * \param listener The listener
96  * \param was_empty If non-zero, the taskprocessor was empty prior to the task being pushed
97  */
98  void (*task_pushed)(struct ast_taskprocessor_listener *listener, int was_empty);
99  /*!
100  * \brief Indicates the task processor has become empty
101  *
102  * \param listener The listener
103  */
105  /*!
106  * \brief Indicates the taskprocessor wishes to die.
107  *
108  * All operations on the task processor must to be stopped in
109  * this callback. This is an opportune time to free the listener's
110  * user data if it is not going to be used anywhere else.
111  *
112  * After this callback returns, it is NOT safe to operate on the
113  * listener's reference to the taskprocessor.
114  *
115  * \param listener The listener
116  */
119 };
120 
121 /*!
122  * \brief Get a reference to the listener's taskprocessor
123  *
124  * This will return the taskprocessor with its reference count increased. Release
125  * the reference to this object by using ast_taskprocessor_unreference()
126  *
127  * \param listener The listener that has the taskprocessor
128  * \return The taskprocessor
129  */
131 
132 /*!
133  * \brief Get the user data from the listener
134  * \param listener The taskprocessor listener
135  * \return The listener's user data
136  */
138 
139 /*!
140  * \brief Allocate a taskprocessor listener
141  *
142  * \since 12.0.0
143  *
144  * This will result in the listener being allocated with the specified
145  * callbacks.
146  *
147  * \param callbacks The callbacks to assign to the listener
148  * \param user_data The user data for the listener
149  * \retval NULL Failure
150  * \retval non-NULL The newly allocated taskprocessor listener
151  */
153 
154 /*!
155  * \brief Get a reference to a taskprocessor with the specified name and create the taskprocessor if necessary
156  *
157  * The default behavior of instantiating a taskprocessor if one does not already exist can be
158  * disabled by specifying the TPS_REF_IF_EXISTS ast_tps_options as the second argument to ast_taskprocessor_get().
159  * \param name The name of the taskprocessor
160  * \param create Use 0 by default or specify TPS_REF_IF_EXISTS to return NULL if the taskprocessor does
161  * not already exist
162  * return A pointer to a reference counted taskprocessor under normal conditions, or NULL if the
163  * TPS_REF_IF_EXISTS reference type is specified and the taskprocessor does not exist
164  * \since 1.6.1
165  */
166 struct ast_taskprocessor *ast_taskprocessor_get(const char *name, enum ast_tps_options create);
167 
168 /*!
169  * \brief Create a taskprocessor with a custom listener
170  *
171  * \since 12.0.0
172  *
173  * Note that when a taskprocessor is created in this way, it does not create
174  * any threads to execute the tasks. This job is left up to the listener.
175  * The listener's start() callback will be called during this function.
176  *
177  * \param name The name of the taskprocessor to create
178  * \param listener The listener for operations on this taskprocessor
179  * \retval NULL Failure
180  * \reval non-NULL success
181  */
183 
184 /*!
185  * \brief Sets the local data associated with a taskprocessor.
186  *
187  * \since 12.0.0
188  *
189  * See ast_taskprocessor_push_local().
190  *
191  * \param tps Task processor.
192  * \param local_data Local data to associate with \a tps.
193  */
195 
196 /*!
197  * \brief Unreference the specified taskprocessor and its reference count will decrement.
198  *
199  * Taskprocessors use astobj2 and will unlink from the taskprocessor singleton container and destroy
200  * themself when the taskprocessor reference count reaches zero.
201  * \param tps taskprocessor to unreference
202  * \return NULL
203  * \since 1.6.1
204  */
206 
207 /*!
208  * \brief Push a task into the specified taskprocessor queue and signal the taskprocessor thread
209  * \param tps The taskprocessor structure
210  * \param task_exe The task handling function to push into the taskprocessor queue
211  * \param datap The data to be used by the task handling function
212  * \retval 0 success
213  * \retval -1 failure
214  * \since 1.6.1
215  */
216 int ast_taskprocessor_push(struct ast_taskprocessor *tps, int (*task_exe)(void *datap), void *datap)
218 
219 /*! \brief Local data parameter */
221  /*! Local data, associated with the taskprocessor. */
222  void *local_data;
223  /*! Data pointer passed with this task. */
224  void *data;
225 };
226 
227 /*!
228  * \brief Push a task into the specified taskprocessor queue and signal the
229  * taskprocessor thread.
230  *
231  * The callback receives a \ref ast_taskprocessor_local struct, which contains
232  * both the provided \a datap pointer, and any local data set on the
233  * taskprocessor with ast_taskprocessor_set_local().
234  *
235  * \param tps The taskprocessor structure
236  * \param task_exe The task handling function to push into the taskprocessor queue
237  * \param datap The data to be used by the task handling function
238  * \retval 0 success
239  * \retval -1 failure
240  * \since 12.0.0
241  */
243  int (*task_exe)(struct ast_taskprocessor_local *local), void *datap)
245 
246 /*!
247  * \brief Indicate the taskprocessor is suspended.
248  *
249  * \since 13.12.0
250  *
251  * \param tps Task processor.
252  * \retval 0 success
253  * \retval -1 failure
254  */
256 
257 /*!
258  * \brief Indicate the taskprocessor is unsuspended.
259  *
260  * \since 13.12.0
261  *
262  * \param tps Task processor.
263  * \retval 0 success
264  * \retval -1 failure
265  */
267 
268 /*!
269  * \brief Get the task processor suspend status
270  *
271  * \since 13.12.0
272  *
273  * \param tps Task processor.
274  * \retval non-zero if the task processor is suspended
275  */
277 
278 /*!
279  * \brief Pop a task off the taskprocessor and execute it.
280  *
281  * \since 12.0.0
282  *
283  * \param tps The taskprocessor from which to execute.
284  * \retval 0 There is no further work to be done.
285  * \retval 1 Tasks still remain in the taskprocessor queue.
286  */
288 
289 /*!
290  * \brief Am I the given taskprocessor's current task.
291  * \since 12.7.0
292  *
293  * \param tps Taskprocessor to check.
294  *
295  * \retval non-zero if current thread is the taskprocessor thread.
296  */
298 
299 /*!
300  * \brief Get the next sequence number to create a human friendly taskprocessor name.
301  * \since 13.8.0
302  *
303  * \return Sequence number for use in creating human friendly taskprocessor names.
304  */
305 unsigned int ast_taskprocessor_seq_num(void);
306 
307 /*!
308  * \brief Append the next sequence number to the given string, and copy into the buffer.
309  *
310  * \param buf Where to copy the appended taskprocessor name.
311  * \param size How large is buf including null terminator.
312  * \param name A name to append the sequence number to.
313  */
314 void ast_taskprocessor_name_append(char *buf, unsigned int size, const char *name);
315 
316 /*!
317  * \brief Build a taskprocessor name with a sequence number on the end.
318  * \since 13.8.0
319  *
320  * \param buf Where to put the built taskprocessor name.
321  * \param size How large is buf including null terminator.
322  * \param format printf format to create the non-sequenced part of the name.
323  *
324  * \note The user supplied part of the taskprocessor name is truncated
325  * to allow the full sequence number to be appended within the supplied
326  * buffer size.
327  *
328  * \return Nothing
329  */
330 void __attribute__((format(printf, 3, 4))) ast_taskprocessor_build_name(char *buf, unsigned int size, const char *format, ...);
331 
332 /*!
333  * \brief Return the name of the taskprocessor singleton
334  * \since 1.6.1
335  */
336 const char *ast_taskprocessor_name(struct ast_taskprocessor *tps);
337 
338 /*!
339  * \brief Return the current size of the taskprocessor queue
340  * \since 13.7.0
341  */
342 long ast_taskprocessor_size(struct ast_taskprocessor *tps);
343 
344 /*!
345  * \brief Get the current taskprocessor high water alert count.
346  * \since 13.10.0
347  *
348  * \retval 0 if no taskprocessors are in high water alert.
349  * \retval non-zero if some task processors are in high water alert.
350  */
351 unsigned int ast_taskprocessor_alert_get(void);
352 
353 
354 /*!
355  * \brief Get the current taskprocessor high water alert count by sybsystem.
356  * \since 13.26.0
357  * \since 16.3.0
358  *
359  * \param subsystem The subsystem name
360  *
361  * \retval 0 if no taskprocessors are in high water alert.
362  * \retval non-zero if some task processors are in high water alert.
363  */
364 unsigned int ast_taskprocessor_get_subsystem_alert(const char *subsystem);
365 
366 /*!
367  * \brief Set the high and low alert water marks of the given taskprocessor queue.
368  * \since 13.10.0
369  *
370  * \param tps Taskprocessor to update queue water marks.
371  * \param low_water New queue low water mark. (-1 to set as 90% of high_water)
372  * \param high_water New queue high water mark.
373  *
374  * \retval 0 on success.
375  * \retval -1 on error (water marks not changed).
376  */
377 int ast_taskprocessor_alert_set_levels(struct ast_taskprocessor *tps, long low_water, long high_water);
378 
379 #endif /* __AST_TASKPROCESSOR_H__ */
A listener for taskprocessors.
const struct ast_taskprocessor_listener_callbacks * callbacks
void ast_taskprocessor_build_name(char *buf, unsigned int size, const char *format,...)
Build a taskprocessor name with a sequence number on the end.
void(* shutdown)(struct ast_taskprocessor_listener *listener)
Indicates the taskprocessor wishes to die.
long ast_taskprocessor_size(struct ast_taskprocessor *tps)
Return the current size of the taskprocessor queue.
void(* emptied)(struct ast_taskprocessor_listener *listener)
Indicates the task processor has become empty.
struct ast_taskprocessor * ast_taskprocessor_listener_get_tps(const struct ast_taskprocessor_listener *listener)
Get a reference to the listener&#39;s taskprocessor.
char buf[BUFSIZE]
Definition: eagi_proxy.c:66
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...
return a reference to a taskprocessor, create one if it does not exist
Definition: taskprocessor.h:75
const char * ast_taskprocessor_name(struct ast_taskprocessor *tps)
Return the name of the taskprocessor singleton.
int ast_taskprocessor_alert_set_levels(struct ast_taskprocessor *tps, long low_water, long high_water)
Set the high and low alert water marks of the given taskprocessor queue.
int ast_taskprocessor_execute(struct ast_taskprocessor *tps)
Pop a task off the taskprocessor and execute it.
void(* dtor)(struct ast_taskprocessor_listener *listener)
int ast_taskprocessor_suspend(struct ast_taskprocessor *tps)
Indicate the taskprocessor is suspended.
static void * listener(void *unused)
Definition: asterisk.c:1476
int ast_taskprocessor_unsuspend(struct ast_taskprocessor *tps)
Indicate the taskprocessor is unsuspended.
ast_tps_options
ast_tps_options for specification of taskprocessor options
Definition: taskprocessor.h:73
int ast_taskprocessor_push_local(struct ast_taskprocessor *tps, int(*task_exe)(struct ast_taskprocessor_local *local), void *datap) attribute_warn_unused_result
Push a task into the specified taskprocessor queue and signal the taskprocessor thread.
Local data parameter.
unsigned int ast_taskprocessor_get_subsystem_alert(const char *subsystem)
Get the current taskprocessor high water alert count by sybsystem.
int ast_taskprocessor_is_task(struct ast_taskprocessor *tps)
Am I the given taskprocessor&#39;s current task.
static const char name[]
Definition: cdr_mysql.c:74
#define attribute_warn_unused_result
Definition: compiler.h:71
struct ast_taskprocessor_listener * ast_taskprocessor_listener_alloc(const struct ast_taskprocessor_listener_callbacks *callbacks, void *user_data)
Allocate a taskprocessor listener.
int ast_taskprocessor_is_suspended(struct ast_taskprocessor *tps)
Get the task processor suspend status.
void * ast_taskprocessor_listener_get_user_data(const struct ast_taskprocessor_listener *listener)
Get the user data from the listener.
return a reference to a taskprocessor ONLY if it already exists
Definition: taskprocessor.h:77
void ast_taskprocessor_set_local(struct ast_taskprocessor *tps, void *local_data)
Sets the local data associated with a taskprocessor.
A ast_taskprocessor structure is a singleton by name.
Definition: taskprocessor.c:69
int ast_taskprocessor_push(struct ast_taskprocessor *tps, int(*task_exe)(void *datap), void *datap) attribute_warn_unused_result
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.
unsigned int ast_taskprocessor_alert_get(void)
Get the current taskprocessor high water alert count.
unsigned int ast_taskprocessor_seq_num(void)
Get the next sequence number to create a human friendly taskprocessor name.
struct ast_taskprocessor * ast_taskprocessor_create_with_listener(const char *name, struct ast_taskprocessor_listener *listener)
Create a taskprocessor with a custom listener.
void(* task_pushed)(struct ast_taskprocessor_listener *listener, int was_empty)
Indicates a task was pushed to the processor.
Definition: taskprocessor.h:98
static snd_pcm_format_t format
Definition: chan_alsa.c:102
int(* start)(struct ast_taskprocessor_listener *listener)
The taskprocessor has started completely.
Definition: taskprocessor.h:91
void ast_taskprocessor_name_append(char *buf, unsigned int size, const char *name)
Append the next sequence number to the given string, and copy into the buffer.