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.  :-)
........


git-svn-id: http://svn.digium.com/svn/asterisk/branches/1.6.2@296083 f38db490-d61c-443f-a65b-d21fe96a405b

1 files changed, 17 insertions, 7 deletions

diff --git a/main/channel.c b/main/channel.c
index f2b2c0210..211a3ab70 100644
--- a/main/channel.c
+++ b/main/channel.c
@@ -3975,13 +3975,23 @@ static int set_format(struct ast_channel *chan, int fmt, int *rawformat, int *fo
 	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));