Fri Aug 24 02:24:25 2007

Asterisk developer's documentation


chanspy.h File Reference

Asterisk PBX channel spy definitions. More...

#include "asterisk/linkedlists.h"

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Data Structures

struct  ast_channel_spy
struct  ast_channel_spy_queue

Enumerations

enum  chanspy_flags {
  CHANSPY_MIXAUDIO = (1 << 0), CHANSPY_READ_VOLADJUST = (1 << 1), CHANSPY_WRITE_VOLADJUST = (1 << 2), CHANSPY_FORMAT_AUDIO = (1 << 3),
  CHANSPY_TRIGGER_MODE = (3 << 4), CHANSPY_TRIGGER_READ = (1 << 4), CHANSPY_TRIGGER_WRITE = (2 << 4), CHANSPY_TRIGGER_NONE = (3 << 4),
  CHANSPY_TRIGGER_FLUSH = (1 << 6)
}
enum  chanspy_states { CHANSPY_NEW = 0, CHANSPY_RUNNING = 1, CHANSPY_DONE = 2, CHANSPY_STOP = 3 }

Functions

int ast_channel_spy_add (struct ast_channel *chan, struct ast_channel_spy *spy)
 Adds a spy to a channel, to begin receiving copies of the channel's audio frames.
void ast_channel_spy_free (struct ast_channel_spy *spy)
 Free a spy.
ast_frameast_channel_spy_read_frame (struct ast_channel_spy *spy, unsigned int samples)
 Read one (or more) frames of audio from a channel being spied upon.
void ast_channel_spy_remove (struct ast_channel *chan, struct ast_channel_spy *spy)
 Remove a spy from a channel.
void ast_channel_spy_stop_by_type (struct ast_channel *chan, const char *type)
 Find all spies of a particular type on a channel and stop them.
void ast_channel_spy_trigger_wait (struct ast_channel_spy *spy)
 Efficiently wait until audio is available for a spy, or an exception occurs.


Detailed Description

Asterisk PBX channel spy definitions.

Definition in file chanspy.h.


Enumeration Type Documentation

enum chanspy_flags

Enumerator:
CHANSPY_MIXAUDIO 
CHANSPY_READ_VOLADJUST 
CHANSPY_WRITE_VOLADJUST 
CHANSPY_FORMAT_AUDIO 
CHANSPY_TRIGGER_MODE 
CHANSPY_TRIGGER_READ 
CHANSPY_TRIGGER_WRITE 
CHANSPY_TRIGGER_NONE 
CHANSPY_TRIGGER_FLUSH 

Definition at line 39 of file chanspy.h.

00039                    {
00040    CHANSPY_MIXAUDIO = (1 << 0),
00041    CHANSPY_READ_VOLADJUST = (1 << 1),
00042    CHANSPY_WRITE_VOLADJUST = (1 << 2),
00043    CHANSPY_FORMAT_AUDIO = (1 << 3),
00044    CHANSPY_TRIGGER_MODE = (3 << 4),
00045    CHANSPY_TRIGGER_READ = (1 << 4),
00046    CHANSPY_TRIGGER_WRITE = (2 << 4),
00047    CHANSPY_TRIGGER_NONE = (3 << 4),
00048    CHANSPY_TRIGGER_FLUSH = (1 << 6),
00049 };

enum chanspy_states

Enumerator:
CHANSPY_NEW  spy not yet operating
CHANSPY_RUNNING  normal operation, spy is still operating
CHANSPY_DONE  spy is stopped and already removed from channel
CHANSPY_STOP  spy requested to stop, still attached to channel

Definition at line 32 of file chanspy.h.

00032                     {
00033    CHANSPY_NEW = 0,     /*!< spy not yet operating */
00034    CHANSPY_RUNNING = 1,    /*!< normal operation, spy is still operating */
00035    CHANSPY_DONE = 2,    /*!< spy is stopped and already removed from channel */
00036    CHANSPY_STOP = 3,    /*!< spy requested to stop, still attached to channel */
00037 };


Function Documentation

int ast_channel_spy_add ( struct ast_channel chan,
struct ast_channel_spy spy 
)

Adds a spy to a channel, to begin receiving copies of the channel's audio frames.

Parameters:
chan The channel to add the spy to.
spy A pointer to ast_channel_spy structure describing how the spy is to be used.
Returns:
0 for success, non-zero for failure
Note: This function performs no locking; you must hold the channel's lock before calling this function.

Definition at line 1369 of file channel.c.

References ast_calloc, ast_clear_flag, ast_cond_init(), AST_FORMAT_SLINEAR, ast_getformatname(), AST_LIST_HEAD_INIT_NOLOCK, AST_LIST_INSERT_HEAD, AST_LIST_INSERT_TAIL, ast_log(), ast_set_flag, ast_test_flag, ast_channel_spy::chan, CHANSPY_FORMAT_AUDIO, CHANSPY_MIXAUDIO, CHANSPY_READ_VOLADJUST, CHANSPY_TRIGGER_MODE, CHANSPY_TRIGGER_NONE, CHANSPY_TRIGGER_READ, CHANSPY_TRIGGER_WRITE, CHANSPY_WRITE_VOLADJUST, ast_channel_spy_queue::format, LOG_DEBUG, LOG_WARNING, option_debug, ast_channel_spy::read_queue, ast_channel::spies, ast_channel_spy::trigger, ast_channel_spy::type, and ast_channel_spy::write_queue.

Referenced by start_spying(), and startmon().

01370 {
01371    /* Link the owner channel to the spy */
01372    spy->chan = chan;
01373 
01374    if (!ast_test_flag(spy, CHANSPY_FORMAT_AUDIO)) {
01375       ast_log(LOG_WARNING, "Could not add channel spy '%s' to channel '%s', only audio format spies are supported.\n",
01376          spy->type, chan->name);
01377       return -1;
01378    }
01379 
01380    if (ast_test_flag(spy, CHANSPY_READ_VOLADJUST) && (spy->read_queue.format != AST_FORMAT_SLINEAR)) {
01381       ast_log(LOG_WARNING, "Cannot provide volume adjustment on '%s' format spies\n",
01382          ast_getformatname(spy->read_queue.format));
01383       return -1;
01384    }
01385 
01386    if (ast_test_flag(spy, CHANSPY_WRITE_VOLADJUST) && (spy->write_queue.format != AST_FORMAT_SLINEAR)) {
01387       ast_log(LOG_WARNING, "Cannot provide volume adjustment on '%s' format spies\n",
01388          ast_getformatname(spy->write_queue.format));
01389       return -1;
01390    }
01391 
01392    if (ast_test_flag(spy, CHANSPY_MIXAUDIO) &&
01393        ((spy->read_queue.format != AST_FORMAT_SLINEAR) ||
01394         (spy->write_queue.format != AST_FORMAT_SLINEAR))) {
01395       ast_log(LOG_WARNING, "Cannot provide audio mixing on '%s'-'%s' format spies\n",
01396          ast_getformatname(spy->read_queue.format), ast_getformatname(spy->write_queue.format));
01397       return -1;
01398    }
01399 
01400    if (!chan->spies) {
01401       if (!(chan->spies = ast_calloc(1, sizeof(*chan->spies)))) {
01402          return -1;
01403       }
01404 
01405       AST_LIST_HEAD_INIT_NOLOCK(&chan->spies->list);
01406       AST_LIST_INSERT_HEAD(&chan->spies->list, spy, list);
01407    } else {
01408       AST_LIST_INSERT_TAIL(&chan->spies->list, spy, list);
01409    }
01410 
01411    if (ast_test_flag(spy, CHANSPY_TRIGGER_MODE) != CHANSPY_TRIGGER_NONE) {
01412       ast_cond_init(&spy->trigger, NULL);
01413       ast_set_flag(spy, CHANSPY_TRIGGER_READ);
01414       ast_clear_flag(spy, CHANSPY_TRIGGER_WRITE);
01415    }
01416 
01417    if (option_debug)
01418       ast_log(LOG_DEBUG, "Spy %s added to channel %s\n",
01419          spy->type, chan->name);
01420 
01421    return 0;
01422 }

void ast_channel_spy_free ( struct ast_channel_spy spy  ) 

Free a spy.

Parameters:
spy The spy to free
Returns:
nothing
Note: This function MUST NOT be called with the spy locked.

Definition at line 1499 of file channel.c.

References ast_cond_destroy(), ast_frfree(), AST_LIST_REMOVE_HEAD, ast_mutex_destroy(), ast_test_flag, CHANSPY_DONE, CHANSPY_TRIGGER_MODE, CHANSPY_TRIGGER_NONE, f, ast_channel_spy::lock, ast_channel_spy::read_queue, ast_channel_spy::status, ast_channel_spy::trigger, and ast_channel_spy::write_queue.

Referenced by channel_spy(), and mixmonitor_thread().

01500 {
01501    struct ast_frame *f = NULL;
01502 
01503    if (spy->status == CHANSPY_DONE)
01504       return;
01505 
01506    /* Switch status to done in case we get called twice */
01507    spy->status = CHANSPY_DONE;
01508 
01509    /* Drop any frames in the queue */
01510    while ((f = AST_LIST_REMOVE_HEAD(&spy->write_queue.list, frame_list)))
01511       ast_frfree(f);
01512    while ((f = AST_LIST_REMOVE_HEAD(&spy->read_queue.list, frame_list)))
01513       ast_frfree(f);
01514 
01515    /* Destroy the condition if in use */
01516    if (ast_test_flag(spy, CHANSPY_TRIGGER_MODE) != CHANSPY_TRIGGER_NONE)
01517       ast_cond_destroy(&spy->trigger);
01518 
01519    /* Destroy our mutex since it is no longer in use */
01520    ast_mutex_destroy(&spy->lock);
01521 
01522    return;
01523 }

struct ast_frame* ast_channel_spy_read_frame ( struct ast_channel_spy spy,
unsigned int  samples 
)

Read one (or more) frames of audio from a channel being spied upon.

Parameters:
spy The spy to operate on
samples The number of audio samples to read
Returns:
NULL for failure, one ast_frame pointer, or a chain of ast_frame pointers
This function can return multiple frames if the spy structure needs to be 'flushed' due to mismatched queue lengths, or if the spy structure is configured to return unmixed audio (in which case each call to this function will return a frame of audio from each side of channel).

Note: This function performs no locking; you must hold the spy's lock before calling this function. You must not hold the channel's lock at the same time.

Definition at line 4659 of file channel.c.

References ast_clear_flag, ast_codec_get_len(), ast_frame_adjust_volume(), ast_frame_slinear_sum(), AST_FRAME_VOICE, ast_frdup(), ast_frfree(), AST_LIST_FIRST, AST_LIST_HEAD_SET_NOLOCK, AST_LIST_NEXT, AST_LIST_REMOVE_HEAD, AST_LIST_TRAVERSE, ast_test_flag, CHANSPY_MIXAUDIO, CHANSPY_READ_VOLADJUST, CHANSPY_TRIGGER_FLUSH, CHANSPY_WRITE_VOLADJUST, copy_data_from_queue(), ast_channel_spy_queue::format, ast_frame::frametype, ast_channel_spy::read_queue, ast_channel_spy::read_vol_adjustment, result, ast_channel_spy_queue::samples, ast_channel_spy::write_queue, and ast_channel_spy::write_vol_adjustment.

Referenced by mixmonitor_thread(), and spy_generate().

04660 {
04661    struct ast_frame *result;
04662    /* buffers are allocated to hold SLINEAR, which is the largest format */
04663         short read_buf[samples];
04664         short write_buf[samples];
04665    struct ast_frame *read_frame;
04666    struct ast_frame *write_frame;
04667    int need_dup;
04668    struct ast_frame stack_read_frame = { .frametype = AST_FRAME_VOICE,
04669                      .subclass = spy->read_queue.format,
04670                      .data = read_buf,
04671                      .samples = samples,
04672                      .datalen = ast_codec_get_len(spy->read_queue.format, samples),
04673    };
04674    struct ast_frame stack_write_frame = { .frametype = AST_FRAME_VOICE,
04675                       .subclass = spy->write_queue.format,
04676                       .data = write_buf,
04677                       .samples = samples,
04678                       .datalen = ast_codec_get_len(spy->write_queue.format, samples),
04679    };
04680 
04681    /* if a flush has been requested, dump everything in whichever queue is larger */
04682    if (ast_test_flag(spy, CHANSPY_TRIGGER_FLUSH)) {
04683       if (spy->read_queue.samples > spy->write_queue.samples) {
04684          if (ast_test_flag(spy, CHANSPY_READ_VOLADJUST)) {
04685             AST_LIST_TRAVERSE(&spy->read_queue.list, result, frame_list)
04686                ast_frame_adjust_volume(result, spy->read_vol_adjustment);
04687          }
04688          result = AST_LIST_FIRST(&spy->read_queue.list);
04689          AST_LIST_HEAD_SET_NOLOCK(&spy->read_queue.list, NULL);
04690          spy->read_queue.samples = 0;
04691       } else {
04692          if (ast_test_flag(spy, CHANSPY_WRITE_VOLADJUST)) {
04693             AST_LIST_TRAVERSE(&spy->write_queue.list, result, frame_list)
04694                ast_frame_adjust_volume(result, spy->write_vol_adjustment);
04695          }
04696          result = AST_LIST_FIRST(&spy->write_queue.list);
04697          AST_LIST_HEAD_SET_NOLOCK(&spy->write_queue.list, NULL);
04698          spy->write_queue.samples = 0;
04699       }
04700       ast_clear_flag(spy, CHANSPY_TRIGGER_FLUSH);
04701       return result;
04702    }
04703 
04704    if ((spy->read_queue.samples < samples) || (spy->write_queue.samples < samples))
04705       return NULL;
04706 
04707    /* short-circuit if both head frames have exactly what we want */
04708    if ((AST_LIST_FIRST(&spy->read_queue.list)->samples == samples) &&
04709        (AST_LIST_FIRST(&spy->write_queue.list)->samples == samples)) {
04710       read_frame = AST_LIST_REMOVE_HEAD(&spy->read_queue.list, frame_list);
04711       write_frame = AST_LIST_REMOVE_HEAD(&spy->write_queue.list, frame_list);
04712 
04713       spy->read_queue.samples -= samples;
04714       spy->write_queue.samples -= samples;
04715 
04716       need_dup = 0;
04717    } else {
04718       copy_data_from_queue(&spy->read_queue, read_buf, samples);
04719       copy_data_from_queue(&spy->write_queue, write_buf, samples);
04720 
04721       read_frame = &stack_read_frame;
04722       write_frame = &stack_write_frame;
04723       need_dup = 1;
04724    }
04725    
04726    if (ast_test_flag(spy, CHANSPY_READ_VOLADJUST))
04727       ast_frame_adjust_volume(read_frame, spy->read_vol_adjustment);
04728 
04729    if (ast_test_flag(spy, CHANSPY_WRITE_VOLADJUST))
04730       ast_frame_adjust_volume(write_frame, spy->write_vol_adjustment);
04731 
04732    if (ast_test_flag(spy, CHANSPY_MIXAUDIO)) {
04733       ast_frame_slinear_sum(read_frame, write_frame);
04734 
04735       if (need_dup)
04736          result = ast_frdup(read_frame);
04737       else {
04738          result = read_frame;
04739          ast_frfree(write_frame);
04740       }
04741    } else {
04742       if (need_dup) {
04743          result = ast_frdup(read_frame);
04744          AST_LIST_NEXT(result, frame_list) = ast_frdup(write_frame);
04745       } else {
04746          result = read_frame;
04747          AST_LIST_NEXT(result, frame_list) = write_frame;
04748       }
04749    }
04750 
04751    return result;
04752 }

void ast_channel_spy_remove ( struct ast_channel chan,
struct ast_channel_spy spy 
)

Remove a spy from a channel.

Parameters:
chan The channel to remove the spy from
spy The spy to be removed
Returns:
nothing
Note: This function performs no locking; you must hold the channel's lock before calling this function.

Definition at line 1489 of file channel.c.

References AST_LIST_REMOVE, ast_channel::spies, spy_cleanup(), and spy_detach().

Referenced by channel_spy().

01490 {
01491    if (!chan->spies)
01492       return;
01493 
01494    AST_LIST_REMOVE(&chan->spies->list, spy, list);
01495    spy_detach(spy, chan);
01496    spy_cleanup(chan);
01497 }

void ast_channel_spy_stop_by_type ( struct ast_channel chan,
const char *  type 
)

Find all spies of a particular type on a channel and stop them.

Parameters:
chan The channel to operate on
type A character string identifying the type of spies to be stopped
Returns:
nothing
Note: This function performs no locking; you must hold the channel's lock before calling this function.

Definition at line 1460 of file channel.c.

References AST_LIST_REMOVE_CURRENT, AST_LIST_TRAVERSE_SAFE_BEGIN, AST_LIST_TRAVERSE_SAFE_END, ast_channel_spy::chan, CHANSPY_RUNNING, ast_channel::spies, spy_cleanup(), spy_detach(), ast_channel_spy::status, and ast_channel_spy::type.

Referenced by mixmonitor_cli(), and stop_mixmonitor_exec().

01461 {
01462    struct ast_channel_spy *spy = NULL;
01463    
01464    if (!chan->spies)
01465       return;
01466 
01467    AST_LIST_TRAVERSE_SAFE_BEGIN(&chan->spies->list, spy, list) {
01468       if ((spy->type == type) && (spy->status == CHANSPY_RUNNING)) {
01469          AST_LIST_REMOVE_CURRENT(&chan->spies->list, list);
01470          spy_detach(spy, chan);
01471       }
01472    }
01473    AST_LIST_TRAVERSE_SAFE_END
01474    spy_cleanup(chan);
01475 }

void ast_channel_spy_trigger_wait ( struct ast_channel_spy spy  ) 

Efficiently wait until audio is available for a spy, or an exception occurs.

Parameters:
spy The spy to wait on
Returns:
nothing
Note: The locking rules for this function are non-obvious... first, you must not hold the channel's lock when calling this function. Second, you must hold the spy's lock before making the function call; while the function runs the lock will be released, and when the trigger event occurs, the lock will be re-obtained. This means that when control returns to your code, you will again hold the spy's lock.

Definition at line 1477 of file channel.c.

References ast_cond_timedwait(), ast_tvadd(), ast_channel_spy::lock, and ast_channel_spy::trigger.

Referenced by mixmonitor_thread().

01478 {
01479    struct timeval tv;
01480    struct timespec ts;
01481 
01482    tv = ast_tvadd(ast_tvnow(), ast_samp2tv(50000, 1000));
01483    ts.tv_sec = tv.tv_sec;
01484    ts.tv_nsec = tv.tv_usec * 1000;
01485 
01486    ast_cond_timedwait(&spy->trigger, &spy->lock, &ts);
01487 }


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