[gnome-builder] sourceview: avoid multiple symbol queries

[Christian Hergert <chergert src gnome org>]

commit ae012050b7a7f0b93191a74c67a56d33f865f414
Author: Christian Hergert <chergert redhat com>
Date:   Thu Jun 14 02:22:46 2018 -0700

    sourceview: avoid multiple symbol queries
    
    We can get a lot of motion events quickly, so we need to avoid doing any
    extra work until the previous request finishes. Otherwise, we just spin
    our wheels doing a whole lot of nothing.

 src/libide/sourceview/ide-source-view.c | 9 +++++++++
 1 file changed, 9 insertions(+)
---
diff --git a/src/libide/sourceview/ide-source-view.c b/src/libide/sourceview/ide-source-view.c
index d40fe60cb..fc186a008 100644
--- a/src/libide/sourceview/ide-source-view.c
+++ b/src/libide/sourceview/ide-source-view.c
@@ -168,6 +168,7 @@ typedef struct
   guint                        show_grid_lines : 1;
   guint                        snippet_completion : 1;
   guint                        waiting_for_capture : 1;
+  guint                        waiting_for_symbol : 1;
 } IdeSourceViewPrivate;
 
 typedef struct
@@ -2386,6 +2387,8 @@ ide_source_view_get_definition_on_mouse_over_cb (GObject      *object,
 
   priv = ide_source_view_get_instance_private (data->self);
 
+  priv->waiting_for_symbol = FALSE;
+
   symbol = ide_buffer_get_symbol_at_location_finish (buffer, result, &error);
 
   if (symbol == NULL)
@@ -2568,6 +2571,12 @@ ide_source_view_real_motion_notify_event (GtkWidget      *widget,
       ide_source_view_reset_definition_highlight (self);
     }
 
+  /* Skip work if we're already active */
+  if (priv->waiting_for_symbol)
+    return ret;
+
+  priv->waiting_for_symbol = TRUE;
+
   data = g_slice_new0 (DefinitionHighlightData);
   data->self = self;
   data->word_start_mark = gtk_text_buffer_create_mark (GTK_TEXT_BUFFER (priv->buffer),