audio: Make scanner report MIME for missing plugins

docs/changelog.rst

@@ -24,6 +24,9 @@ Bug fix release.
 - Audio: Fix timeout handling in scanner. This regression caused timeouts to
   expire before it should, causing scans to fail.
 
+- Audio: Update scanner to emit MIME type instead of an error when missing a
+  plugin.
+
 
 v1.1.0 (2015-08-09)
 ===================

mopidy/audio/scan.py

@@ -12,8 +12,6 @@ from mopidy import exceptions
 from mopidy.audio import utils
 from mopidy.internal import encoding
 
-_missing_plugin_desc = gst.pbutils.missing_plugin_message_get_description
-
 _Result = collections.namedtuple(
     'Result', ('uri', 'tags', 'duration', 'seekable', 'mime', 'playable'))
 
@@ -134,7 +132,7 @@ def _process(pipeline, timeout_ms):
     clock = pipeline.get_clock()
     bus = pipeline.get_bus()
     timeout = timeout_ms * gst.MSECOND
-    tags, mime, have_audio, missing_description = {}, None, False, None
+    tags, mime, have_audio, missing_message = {}, None, False, None
 
     types = (gst.MESSAGE_ELEMENT | gst.MESSAGE_APPLICATION | gst.MESSAGE_ERROR
              | gst.MESSAGE_EOS | gst.MESSAGE_ASYNC_DONE | gst.MESSAGE_TAG)
@@ -147,8 +145,7 @@ def _process(pipeline, timeout_ms):
             break
         elif message.type == gst.MESSAGE_ELEMENT:
             if gst.pbutils.is_missing_plugin_message(message):
-                missing_description = encoding.locale_decode(
-                    _missing_plugin_desc(message))
+                missing_message = message
         elif message.type == gst.MESSAGE_APPLICATION:
             if message.structure.get_name() == 'have-type':
                 mime = message.structure['caps'].get_name()
@@ -158,8 +155,10 @@ def _process(pipeline, timeout_ms):
                 have_audio = True
         elif message.type == gst.MESSAGE_ERROR:
             error = encoding.locale_decode(message.parse_error()[0])
-            if missing_description:
-                error = '%s (%s)' % (missing_description, error)
+            if missing_message and not mime:
+                caps = missing_message.structure['detail']
+                mime = caps.get_structure(0).get_name()
+                return tags, mime, have_audio
             raise exceptions.ScannerError(error)
         elif message.type == gst.MESSAGE_EOS:
             return tags, mime, have_audio

tests/audio/test_scan.py

@@ -109,6 +109,17 @@ class ScannerTest(unittest.TestCase):
         wav = path_to_data_dir('scanner/empty.wav')
         self.assertEqual(self.result[wav].duration, 0)
 
+    def test_uri_list(self):
+        path = path_to_data_dir('scanner/playlist.m3u')
+        self.scan([path])
+        self.assertEqual(self.result[path].mime, 'text/uri-list')
+
+    def test_text_plain(self):
+        # GStreamer decode bin hardcodes bad handling of text plain :/
+        path = path_to_data_dir('scanner/plain.txt')
+        self.scan([path])
+        self.assertIn(path, self.errors)
+
     @unittest.SkipTest
     def test_song_without_time_is_handeled(self):
         pass

tests/data/scanner/plain.txt

@@ -0,0 +1 @@
+Some plain text file with nothing special in it.

tests/data/scanner/playlist.m3u

@@ -0,0 +1 @@
+http://example.com/