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Convert the ast_channel data structure over to the astobj2 framework.

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There is a lot that could be said about this, but the patch is a big 
improvement for performance, stability, code maintainability, 
and ease of future code development.

The channel list is no longer an unsorted linked list.  The main container 
for channels is an astobj2 hash table.  All of the code related to searching 
for channels or iterating active channels has been rewritten.  Let n be 
the number of active channels.  Iterating the channel list has gone from 
O(n^2) to O(n).  Searching for a channel by name went from O(n) to O(1).  
Searching for a channel by extension is still O(n), but uses a new method 
for doing so, which is more efficient.

The ast_channel object is now a reference counted object.  The benefits 
here are plentiful.  Some benefits directly related to issues in the 
previous code include:

1) When threads other than the channel thread owning a channel wanted 
   access to a channel, it had to hold the lock on it to ensure that it didn't 
   go away.  This is no longer a requirement.  Holding a reference is 
   sufficient.

2) There are places that now require less dealing with channel locks.

3) There are places where channel locks are held for much shorter periods 
   of time.

4) There are places where dealing with more than one channel at a time becomes 
   _MUCH_ easier.  ChanSpy is a great example of this.  Writing code in the 
   future that deals with multiple channels will be much easier.

Some additional information regarding channel locking and reference count 
handling can be found in channel.h, where a new section has been added that 
discusses some of the rules associated with it.

Mark Michelson also assisted with the development of this patch.  He did the 
conversion of ChanSpy and introduced a new API, ast_autochan, which makes it 
much easier to deal with holding on to a channel pointer for an extended period 
of time and having it get automatically updated if the channel gets masqueraded.
Mark was also a huge help in the code review process.

Thanks to David Vossel for his assistance with this branch, as well.  David 
did the conversion of the DAHDIScan application by making it become a wrapper 
for ChanSpy internally.

The changes come from the svn/asterisk/team/russell/ast_channel_ao2 branch.

Review: http://reviewboard.digium.com/r/203/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@190423 65c4cc65-6c06-0410-ace0-fbb531ad65f3
This commit is contained in:
Russell Bryant
2009-04-24 14:04:26 +00:00
parent f314c5f13f
commit cba19c8a67
42 changed files with 1732 additions and 1514 deletions
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100
apps/app_mixmonitor.c
View File

@@ -45,6 +45,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
#include "asterisk/cli.h"
#include "asterisk/app.h"
#include "asterisk/channel.h"
#include "asterisk/autochan.h"
/*** DOCUMENTATION
<application name="MixMonitor" language="en_US">
@@ -138,7 +139,7 @@ struct mixmonitor {
char *post_process;
char *name;
unsigned int flags;
struct mixmonitor_ds *mixmonitor_ds;
struct ast_autochan *autochan;
};
enum {
@@ -164,50 +165,6 @@ AST_APP_OPTIONS(mixmonitor_opts, {
AST_APP_OPTION_ARG('W', MUXFLAG_VOLUME, OPT_ARG_VOLUME),
});
/* This structure is used as a means of making sure that our pointer to
* the channel we are monitoring remains valid. This is very similar to
* what is used in app_chanspy.c.
*/
struct mixmonitor_ds {
struct ast_channel *chan;
/* These condition variables are used to be sure that the channel
* hangup code completes before the mixmonitor thread attempts to
* free this structure. The combination of a bookean flag and a
* ast_cond_t ensure that no matter what order the threads run in,
* we are guaranteed to never have the waiting thread block forever
* in the case that the signaling thread runs first.
*/
unsigned int destruction_ok;
ast_cond_t destruction_condition;
ast_mutex_t lock;
};
static void mixmonitor_ds_destroy(void *data)
{
struct mixmonitor_ds *mixmonitor_ds = data;
ast_mutex_lock(&mixmonitor_ds->lock);
mixmonitor_ds->chan = NULL;
mixmonitor_ds->destruction_ok = 1;
ast_cond_signal(&mixmonitor_ds->destruction_condition);
ast_mutex_unlock(&mixmonitor_ds->lock);
}
static void mixmonitor_ds_chan_fixup(void *data, struct ast_channel *old_chan, struct ast_channel *new_chan)
{
struct mixmonitor_ds *mixmonitor_ds = data;
ast_mutex_lock(&mixmonitor_ds->lock);
mixmonitor_ds->chan = new_chan;
ast_mutex_unlock(&mixmonitor_ds->lock);
}
static struct ast_datastore_info mixmonitor_ds_info = {
.type = "mixmonitor",
.destroy = mixmonitor_ds_destroy,
.chan_fixup = mixmonitor_ds_chan_fixup,
};
static int startmon(struct ast_channel *chan, struct ast_audiohook *audiohook)
{
struct ast_channel *peer = NULL;
@@ -249,9 +206,7 @@ static void *mixmonitor_thread(void *obj)
if (!(fr = ast_audiohook_read_frame(&mixmonitor->audiohook, SAMPLES_PER_FRAME, AST_AUDIOHOOK_DIRECTION_BOTH, AST_FORMAT_SLINEAR)))
continue;
ast_mutex_lock(&mixmonitor->mixmonitor_ds->lock);
if (!ast_test_flag(mixmonitor, MUXFLAG_BRIDGED) || (mixmonitor->mixmonitor_ds->chan && ast_bridged_channel(mixmonitor->mixmonitor_ds->chan))) {
ast_mutex_unlock(&mixmonitor->mixmonitor_ds->lock);
if (!ast_test_flag(mixmonitor, MUXFLAG_BRIDGED) || (mixmonitor->autochan->chan && ast_bridged_channel(mixmonitor->autochan->chan))) {
/* Initialize the file if not already done so */
if (!fs && !errflag) {
oflags = O_CREAT | O_WRONLY;
@@ -271,10 +226,7 @@ static void *mixmonitor_thread(void *obj)
/* Write out frame */
if (fs)
ast_writestream(fs, fr);
} else {
ast_mutex_unlock(&mixmonitor->mixmonitor_ds->lock);
}
/* All done! free it. */
ast_frame_free(fr, 0);
@@ -294,48 +246,12 @@ static void *mixmonitor_thread(void *obj)
ast_safe_system(mixmonitor->post_process);
}
ast_mutex_lock(&mixmonitor->mixmonitor_ds->lock);
if (!mixmonitor->mixmonitor_ds->destruction_ok) {
ast_cond_wait(&mixmonitor->mixmonitor_ds->destruction_condition, &mixmonitor->mixmonitor_ds->lock);
}
ast_mutex_unlock(&mixmonitor->mixmonitor_ds->lock);
ast_mutex_destroy(&mixmonitor->mixmonitor_ds->lock);
ast_cond_destroy(&mixmonitor->mixmonitor_ds->destruction_condition);
ast_free(mixmonitor->mixmonitor_ds);
ast_autochan_destroy(mixmonitor->autochan);
ast_free(mixmonitor);
return NULL;
}
static int setup_mixmonitor_ds(struct mixmonitor *mixmonitor, struct ast_channel *chan)
{
struct ast_datastore *datastore = NULL;
struct mixmonitor_ds *mixmonitor_ds;
if (!(mixmonitor_ds = ast_calloc(1, sizeof(*mixmonitor_ds)))) {
return -1;
}
ast_mutex_init(&mixmonitor_ds->lock);
ast_cond_init(&mixmonitor_ds->destruction_condition, NULL);
if (!(datastore = ast_datastore_alloc(&mixmonitor_ds_info, NULL))) {
ast_free(mixmonitor_ds);
return -1;
}
/* No need to lock mixmonitor_ds since this is still operating in the channel's thread */
mixmonitor_ds->chan = chan;
datastore->data = mixmonitor_ds;
ast_channel_lock(chan);
ast_channel_datastore_add(chan, datastore);
ast_channel_unlock(chan);
mixmonitor->mixmonitor_ds = mixmonitor_ds;
return 0;
}
static void launch_monitor_thread(struct ast_channel *chan, const char *filename, unsigned int flags,
int readvol, int writevol, const char *post_process)
{
@@ -369,7 +285,7 @@ static void launch_monitor_thread(struct ast_channel *chan, const char *filename
/* Copy over flags and channel name */
mixmonitor->flags = flags;
if (setup_mixmonitor_ds(mixmonitor, chan)) {
if (!(mixmonitor->autochan = ast_autochan_setup(chan))) {
return;
}
mixmonitor->name = (char *) mixmonitor + sizeof(*mixmonitor);
@@ -512,12 +428,14 @@ static char *handle_cli_mixmonitor(struct ast_cli_entry *e, int cmd, struct ast_
if (a->argc < 3)
return CLI_SHOWUSAGE;
if (!(chan = ast_get_channel_by_name_prefix_locked(a->argv[2], strlen(a->argv[2])))) {
if (!(chan = ast_channel_get_by_name_prefix(a->argv[2], strlen(a->argv[2])))) {
ast_cli(a->fd, "No channel matching '%s' found.\n", a->argv[2]);
/* Technically this is a failure, but we don't want 2 errors printing out */
return CLI_SUCCESS;
}
ast_channel_lock(chan);
if (!strcasecmp(a->argv[1], "start")) {
mixmonitor_exec(chan, a->argv[3]);
ast_channel_unlock(chan);
@@ -526,6 +444,8 @@ static char *handle_cli_mixmonitor(struct ast_cli_entry *e, int cmd, struct ast_
ast_audiohook_detach_source(chan, mixmonitor_spy_type);
}
chan = ast_channel_unref(chan);
return CLI_SUCCESS;
}