[gnome-network-displays] meta-provider: Do not cache matches in hash table

[Benjamin Berg <bberg src gnome org>]

commit 7581f1ddb43bc986c227e701a5bd20061ab01e68
Author: Benjamin Berg <bberg redhat com>
Date:   Tue Apr 20 12:22:49 2021 +0200

    meta-provider: Do not cache matches in hash table
    
    This is less efficient, but we did not delete matches again from our
    lookup table, and the fix for that is also not great. So just do a flat
    search across everything, which should be entirely fine because we
    should never have more than a small amount of sinks.

 src/nd-meta-provider.c | 40 +++-------------------------------------
 src/nd-meta-sink.c     | 38 ++++++++++++++++++++++++++++++++++++++
 src/nd-meta-sink.h     |  3 ++-
 3 files changed, 43 insertions(+), 38 deletions(-)
---
diff --git a/src/nd-meta-provider.c b/src/nd-meta-provider.c
index 2f8cbff..397f834 100644
--- a/src/nd-meta-provider.c
+++ b/src/nd-meta-provider.c
@@ -26,7 +26,6 @@ struct _NdMetaProvider
 
   gboolean    discover;
 
-  GHashTable *deduplicate;
   GPtrArray  *sinks;
   GPtrArray  *providers;
 };
@@ -49,44 +48,22 @@ G_DEFINE_TYPE_EXTENDED (NdMetaProvider, nd_meta_provider, G_TYPE_OBJECT, 0,
                        )
 
 
-static void
-deduplicate_add_meta_sink (NdMetaProvider *meta_provider, NdMetaSink *meta_sink)
-{
-  g_autoptr(GPtrArray) meta_matches = NULL;
-
-  g_object_get (meta_sink, "matches", &meta_matches, NULL);
-  g_assert (meta_matches != NULL);
-
-  for (gint i = 0; i < meta_matches->len; i++)
-    {
-      gchar *match;
-      match = meta_matches->pdata[i];
-
-      g_hash_table_insert (meta_provider->deduplicate, g_strdup (match), meta_sink);
-    }
-}
-
 static void
 provider_sink_added_cb (NdMetaProvider *meta_provider, NdSink *sink, NdProvider *provider)
 {
   g_autoptr(GPtrArray) sink_matches = NULL;
   g_autoptr(GPtrArray) meta_sinks = NULL;
   NdMetaSink *meta_sink;
-  gchar *match;
 
   g_object_get (sink, "matches", &sink_matches, NULL);
   g_assert (sink_matches != NULL);
 
   meta_sinks = g_ptr_array_new ();
 
-  for (gint i = 0; i < sink_matches->len; i++)
+  for (gint i = 0; i < meta_provider->sinks->len; i++)
     {
-      match = sink_matches->pdata[i];
-
-      meta_sink = g_hash_table_lookup (meta_provider->deduplicate, match);
-
-      if (meta_sink)
-        g_ptr_array_add (meta_sinks, meta_sink);
+      if (nd_meta_sink_matches_sink (g_ptr_array_index (meta_provider->sinks, i), sink))
+        g_ptr_array_add (meta_sinks, g_ptr_array_index (meta_provider->sinks, i));
     }
 
   if (meta_sinks->len > 1)
@@ -120,9 +97,6 @@ provider_sink_added_cb (NdMetaProvider *meta_provider, NdSink *sink, NdProvider
       g_signal_emit_by_name (meta_provider, "sink-added", meta_sink);
       g_ptr_array_add (meta_provider->sinks, meta_sink);
     }
-
-  /* Add/Update matches in the deduplication dictionary */
-  deduplicate_add_meta_sink (meta_provider, meta_sink);
 }
 
 static void
@@ -154,10 +128,6 @@ provider_sink_removed_cb (NdMetaProvider *meta_provider, NdSink *sink, NdProvide
 
       return;
     }
-
-  /* Add/Update matches in the deduplication dictionary as we will
-   * have removed too many. */
-  deduplicate_add_meta_sink (meta_provider, meta_sink);
 }
 
 static void
@@ -213,8 +183,6 @@ nd_meta_provider_finalize (GObject *object)
 {
   NdMetaProvider *meta_provider = ND_META_PROVIDER (object);
 
-  g_clear_pointer (&meta_provider->deduplicate, g_hash_table_unref);
-
   g_ptr_array_free (meta_provider->sinks, TRUE);
   meta_provider->sinks = NULL;
   g_ptr_array_free (meta_provider->providers, TRUE);
@@ -252,8 +220,6 @@ nd_meta_provider_init (NdMetaProvider *meta_provider)
 
   meta_provider->sinks = g_ptr_array_new_with_free_func (g_object_unref);
   meta_provider->providers = g_ptr_array_new_with_free_func (g_object_unref);
-
-  meta_provider->deduplicate = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, NULL);
 }
 
 /******************************************************************
diff --git a/src/nd-meta-sink.c b/src/nd-meta-sink.c
index 25117f1..0817184 100644
--- a/src/nd-meta-sink.c
+++ b/src/nd-meta-sink.c
@@ -377,6 +377,44 @@ nd_meta_sink_has_sink (NdMetaSink *meta_sink,
   return g_ptr_array_find (meta_sink->sinks, sink, NULL);
 }
 
+/**
+ * nd_meta_sink_matches_sink:
+ * @meta_sink: a #NdMetaSink
+ * @sink: a #NdSink
+ *
+ * Checks whether meta sink can be considered equal to the given sink.
+ *
+ * Returns:
+ *   Whether @sink should be contained in @meta_sink.
+ */
+gboolean
+nd_meta_sink_matches_sink (NdMetaSink *meta_sink,
+                           NdSink     *sink)
+{
+  g_autoptr(GPtrArray) needles = NULL;
+
+  g_object_get (sink, "matches", &needles, NULL);
+
+  g_return_val_if_fail (needles, FALSE);
+
+  for (gint i = 0; i < meta_sink->sinks->len; i++)
+    {
+      g_autoptr(GPtrArray) sub_matches = NULL;
+
+      g_object_get (g_ptr_array_index (meta_sink->sinks, i),
+                    "matches", &sub_matches,
+                    NULL);
+
+      for (gint j = 0; j < needles->len; j++)
+        if (g_ptr_array_find_with_equal_func (sub_matches,
+                                              g_ptr_array_index (needles, j),
+                                              g_str_equal, NULL))
+          return TRUE;
+    }
+
+  return FALSE;
+}
+
 NdMetaSink *
 nd_meta_sink_new (NdSink *sink)
 {
diff --git a/src/nd-meta-sink.h b/src/nd-meta-sink.h
index 4c3d2ce..bf0883e 100644
--- a/src/nd-meta-sink.h
+++ b/src/nd-meta-sink.h
@@ -34,6 +34,7 @@ gboolean              nd_meta_sink_remove_sink (NdMetaSink *meta_sink,
                                                 NdSink     *sink);
 gboolean              nd_meta_sink_has_sink (NdMetaSink *meta_sink,
                                              NdSink     *sink);
-
+gboolean              nd_meta_sink_matches_sink (NdMetaSink *meta_sink,
+                                                 NdSink     *sink);
 
 G_END_DECLS