registry: Glob pattern matching for plugin ranks

Source names can be constructed partially with unique identifiers, making
it difficult to match directly to the static identifiers in
GRL_PLUGIN_RANKS.

Introduce glob pattern matching for GRL_PLUGIN_RANKS, which allows for
example GRL_PLUGIN_RANKS="grl-lastfm-cover*:3".

Add a short explanation and example to the documentation as well.

https://bugzilla.gnome.org/show_bug.cgi?id=761695
https://gitlab.gnome.org/GNOME/grilo/merge_requests/17

2 files changed, 32 insertions, 0 deletions

diff --git a/doc/grilo/environment-setup.xml b/doc/grilo/environment-setup.xml
index b2a90ae..96267af 100644
--- a/doc/grilo/environment-setup.xml
+++ b/doc/grilo/environment-setup.xml
@@ -150,5 +150,21 @@ $ export GRL_DEBUG=registry:*,youtube:warning
 $ export GRL_PLUGIN_RANKS=youtube:5,bookmarks:-4
     </programlisting>
 
+    <para>
+      Some plugins extend their plugin name with login specific identifiers.
+      To match these plugins the ranks environment variable allows for simple
+      glob pattern matching with the '?' and '*' wildcards. This can of course
+      also be used in other situations.
+      Here is one example:
+    </para>
+
+    <programlisting>
+# Set the rank of all coverart plugins to 2, but the Last.FM
+# coverart plugin whether logged in or not to 5.
+# Note that order is important here: the ranks are interpreted from
+# right to left.
+$ export GRL_PLUGIN_RANKS=grl-lastfm-cover*:5,*cover*:2
+    </programlisting>
+
   </section>
 </section>
diff --git a/src/grl-registry.c b/src/grl-registry.c
index a6189b7..27fd41c 100644
--- a/src/grl-registry.c
+++ b/src/grl-registry.c
@@ -380,9 +380,25 @@ set_source_rank (GrlRegistry *registry, GrlSource *source)
   rank =
     GPOINTER_TO_INT (g_hash_table_lookup (registry->priv->ranks,
                                           grl_source_get_id (source)));
+
+  if (!rank) {
+    GHashTableIter iter;
+    gpointer key, value;
+
+    g_hash_table_iter_init(&iter, registry->priv->ranks);
+
+    while (g_hash_table_iter_next (&iter, &key, &value)) {
+      if (g_pattern_match_simple (key, grl_source_get_id (source))) {
+        rank = GPOINTER_TO_INT (value);
+        break;
+      }
+    }
+  }
+
   if (!rank) {
     rank = GRL_RANK_DEFAULT;
   }
+
   g_object_set (source, "rank", rank, NULL);
   GRL_DEBUG ("Source rank '%s' : %d", grl_source_get_id (source), rank);
 }