Merged revisions 296083 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/1.6.2

................
  r296083 | russell | 2010-11-24 14:23:11 -0600 (Wed, 24 Nov 2010) | 19 lines
  
  Merged revisions 296082 via svnmerge from 
  https://origsvn.digium.com/svn/asterisk/branches/1.4
  
  ........
    r296082 | russell | 2010-11-24 14:22:32 -0600 (Wed, 24 Nov 2010) | 12 lines
    
    Fix false reporting of an error by set_format().
    
    In the case that the native format was able to be changed to match the
    new requested format, the code proceeded to attempt to build a translation
    path, anyway.  The result would be NULL, since no translation path is
    necessary and resulted in this function thinking an error has occurred.
    This case is now specifically caught and no attempt to build a translation
    path is attempted.
    
    Thanks to our automated tests and bamboo.asterisk.org for catching this problem
    and making a whole lot of noise when things started failing.  :-)
  ........
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git-svn-id: http://svn.digium.com/svn/asterisk/branches/1.8@296084 f38db490-d61c-443f-a65b-d21fe96a405b

1 files changed, 17 insertions, 7 deletions

diff --git a/main/channel.c b/main/channel.c
index b0bdede94..259a9f324 100644
--- a/main/channel.c
+++ b/main/channel.c
@@ -4994,13 +4994,23 @@ static int set_format(struct ast_channel *chan, format_t fmt, format_t *rawforma
 	if (*trans)
 		ast_translator_free_path(*trans);
 	/* Build a translation path from the raw format to the desired format */
-	if (!direction)
-		/* reading */
-		*trans = ast_translator_build_path(*format, *rawformat);
-	else
-		/* writing */
-		*trans = ast_translator_build_path(*rawformat, *format);
-	res = *trans ? 0 : -1;
+	if (*format == *rawformat) {
+		/*
+		 * If we were able to swap the native format to the format that
+		 * has been requested, then there is no need to try to build
+		 * a translation path.
+		 */
+		res = 0;
+	} else {
+		if (!direction) {
+			/* reading */
+			*trans = ast_translator_build_path(*format, *rawformat);
+		} else {
+			/* writing */
+			*trans = ast_translator_build_path(*rawformat, *format);
+		}
+		res = *trans ? 0 : -1;
+	}
 	ast_channel_unlock(chan);
 	ast_debug(1, "Set channel %s to %s format %s\n", chan->name,
 		direction ? "write" : "read", ast_getformatname(fmt));