simplify the ast_channel walking routines.
authorLuigi Rizzo <rizzo@icir.org>
Sun, 16 Apr 2006 16:58:56 +0000 (16:58 +0000)
committerLuigi Rizzo <rizzo@icir.org>
Sun, 16 Apr 2006 16:58:56 +0000 (16:58 +0000)
(the previous version was mine, but this way it is definitely
more readable).

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@20543 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channel.c

index 9d0efd5..5e2fe50 100644 (file)
--- a/channel.c
+++ b/channel.c
@@ -793,60 +793,48 @@ static struct ast_channel *channel_find_locked(const struct ast_channel *prev,
                                               const char *context, const char *exten)
 {
        const char *msg = prev ? "deadlock" : "initial deadlock";
-       int retries, done;
+       int retries;
        struct ast_channel *c;
 
        for (retries = 0; retries < 10; retries++) {
+               int done;
                AST_LIST_LOCK(&channels);
                AST_LIST_TRAVERSE(&channels, c, chan_list) {
-                       if (!prev) {
-                               /* want head of list */
-                               if (!name && !exten)
-                                       break;
-                               if (name) {
-                                       /* want match by full name */
-                                       if (!namelen) {
-                                               if (!strcasecmp(c->name, name))
-                                                       break;
-                                               else
-                                                       continue;
-                                       }
-                                       /* want match by name prefix */
-                                       if (!strncasecmp(c->name, name, namelen))
-                                               break;
-                               } else if (exten) {
-                                       /* want match by context and exten */
-                                       if (context && (strcasecmp(c->context, context) &&
-                                                       strcasecmp(c->macrocontext, context)))
-                                               continue;
-                                       /* match by exten */
-                                       if (strcasecmp(c->exten, exten) &&
-                                           strcasecmp(c->macroexten, exten))
-                                               continue;
-                                       else
-                                               break;
-                               }
-                       } else if (c == prev) { /* found, return c->next */
+                       if (prev) {     /* look for next item */
+                               if (c != prev)  /* not this one */
+                                       continue;
+                               /* found, prepare to return c->next */
                                c = AST_LIST_NEXT(c, chan_list);
-                               break;
+                       } else if (name) { /* want match by name */
+                               if ( (!namelen && strcasecmp(c->name, name)) ||
+                                    (namelen && strncasecmp(c->name, name, namelen)) )
+                                       continue;       /* name match failed */
+                       } else if (exten) {
+                               if (context && strcasecmp(c->context, context) &&
+                                               strcasecmp(c->macrocontext, context))
+                                       continue;       /* context match failed */
+                               if (strcasecmp(c->exten, exten) &&
+                                               strcasecmp(c->macroexten, exten))
+                                       continue;       /* exten match failed */
                        }
+                       /* if we get here, c points to the desired record */
+                       break;
                }
                /* exit if chan not found or mutex acquired successfully */
-               done = (c == NULL) || (ast_mutex_trylock(&c->lock) == 0);
-               /* this is slightly unsafe, as we _should_ hold the lock to access c->name */
-               if (!done && c)
-                       ast_log(LOG_DEBUG, "Avoiding %s for '%s'\n", msg, c->name);
+               done = c == NULL || ast_mutex_trylock(&c->lock) == 0;
+               if (!done)
+                       ast_log(LOG_DEBUG, "Avoiding %s for channel '%p'\n", msg, c);
                AST_LIST_UNLOCK(&channels);
                if (done)
                        return c;
-               usleep(1);
+               usleep(1);      /* give other threads a chance before retrying */
        }
        /*
         * c is surely not null, but we don't have the lock so cannot
         * access c->name
         */
-       ast_log(LOG_WARNING, "Avoided %s for '%p', %d retries!\n",
-               msg, c, retries);
+       ast_log(LOG_WARNING, "Failure, could not lock '%p' after %d retries!\n",
+               c, retries);
 
        return NULL;
 }