check for md5sink in pipeline

Original commit message from CVS:
check for md5sink in pipeline

tools/gst-md5sum.1.in

@@ -16,9 +16,11 @@ should print out the same checksum as
 
 	md5sum music.mp3
   
-The pipeline should be incomplete, that is, a final sink element
+If the pipeline contains an md5sink element, gst-md5sum will query it
-should be omitted, so that gst\-md5sum can connect the pipeline to
+for the md5sum at the end of pipeline iteration.
-an md5sink element.
+
+If it doesn't contain an md5sink element, gst-md5sum will automatically
+connect an md5sink to the right hand side of the given pipeline.
 
 See the man page for gst\-launch or the GStreamer docuementation for 
 more information on how to create a PARTIAL\-PIPELINE\-DESCRIPTION.
@@ -52,3 +54,27 @@ Add directories separated with ':' to the plugin search path
 .BR gst\-launch (1)
 .SH "AUTHOR"
 The GStreamer team at http://gstreamer.net/
+***************
+*** 16,24 ****
+  
+  	md5sum music.mp3
+  
+  The pipeline should be incomplete, that is, a final sink element
+- should be omitted, so that gst\-md5sum can connect the pipeline to
+- an md5sink element.
+  
+  See the man page for gst\-launch or the GStreamer docuementation for 
+  more information on how to create a PARTIAL\-PIPELINE\-DESCRIPTION.
+--- 16,27 ----
+  
+  	md5sum music.mp3
+  
++ If the pipeline contains an md5sink element, gst-md5sum will query it
++ for the md5sum at the end of pipeline iteration.
++ 
++ If it doesn't contain an md5sink element, gst-md5sum will automatically
++ connect an md5sink to the right hand side of the given pipeline.
+  The pipeline should be incomplete, that is, a final sink element
+  
+  See the man page for gst\-launch or the GStreamer docuementation for 
+  more information on how to create a PARTIAL\-PIPELINE\-DESCRIPTION.

tools/gst-md5sum.c

@@ -59,7 +59,7 @@ main (int argc, char *argv[])
     POPT_TABLEEND
   };
 
-  GstElement *pipeline;
+  GstElement *pipeline = NULL;
   gchar **argvn;
   GError *error = NULL;
   GstElement *md5sink;
@@ -71,15 +71,38 @@ main (int argc, char *argv[])
 
   gst_init_with_popt_table (&argc, &argv, options);
 
+  /* make a parseable argvn array */
+  argvn = g_new0 (char *, argc);
+  memcpy (argvn, argv + 1, sizeof (char *) * (argc - 1));
+
+  /* Check if we have an element already that is called md5sink0
+     in the pipeline; if not, add one */
+  pipeline = (GstElement*) gst_parse_launchv ((const gchar**) argvn, &error);
+  if (!pipeline) {
+    if (error)
+    {
+      g_warning ("pipeline could not be constructed: %s\n", error->message);
+      g_error_free (error);
+    }
+    else
+      g_warning ("pipeline could not be constructed\n");
+    return 1;
+  }
+
+  md5sink = gst_bin_get_by_name (GST_BIN (pipeline), "md5sink0");
+  if (md5sink == NULL)
+  {
+    g_print ("adding an md5sink element to the pipeline\n");
     /* make a null-terminated version of argv with ! md5sink appended
      * ! is stored in argvn[argc - 1], md5sink in argvn[argc],
      * NULL pointer in argvn[argc + 1] */
+    g_free (argvn);
     argvn = g_new0 (char *, argc + 2);
     memcpy (argvn, argv + 1, sizeof (char *) * (argc - 1));
     argvn[argc - 1] = g_strdup_printf ("!");
     argvn[argc] = g_strdup_printf ("md5sink");
-
     pipeline = (GstElement*) gst_parse_launchv ((const gchar**) argvn, &error);
+  }
 
   if (!pipeline) {
     if (error)