Bug 588273 - Make number of validated rows depend on time, not row count

Previously, do_validate_rows() validated 300 rows per iteration. While
this is usually not problematic, as the typical tree view contains less
than 100 rows. Tree views with a lot of columns or complex cell
renderers could take inacceptably long, like:
- Epiphany's location bar entry completion has multiline and marked up
  text in every cell. Validating a single row took ~1.5ms here.
- In the list view in Nautilus, When enabling all columns, validating a
  single row would take ~3ms.
With 300 rows per iteration, that made those examples take 500ms/1s in a
signle main loop callback, and this obviously caused responsiveness
problems.

Now the code uses a timer and limits the time for validating rows to
30ms. This can cause less lines to be invalidated per call, so the
function might be called more often, but generally results in more
responsive applications.

diff --git a/gtk/gtktreeview.c b/gtk/gtktreeview.c
index b4d4708761fbcaeeb5480731b9c3c1b16615c56b..0e52f92a9542d0c96ca46ffab039fd5f3b9a7bc8 100644 (file)
--- a/gtk/gtktreeview.c
+++ b/gtk/gtktreeview.c
@@ -48,7 +48,7 @@
 
 #define GTK_TREE_VIEW_PRIORITY_VALIDATE (GDK_PRIORITY_REDRAW + 5)
 #define GTK_TREE_VIEW_PRIORITY_SCROLL_SYNC (GTK_TREE_VIEW_PRIORITY_VALIDATE + 2)
-#define GTK_TREE_VIEW_NUM_ROWS_PER_IDLE 500
+#define GTK_TREE_VIEW_TIME_MS_PER_IDLE 30
 #define SCROLL_EDGE_SIZE 15
 #define EXPANDER_EXTRA_PADDING 4
 #define GTK_TREE_VIEW_SEARCH_DIALOG_TIMEOUT 5000
@@ -2043,9 +2043,8 @@ gtk_tree_view_size_request (GtkWidget      *widget,
   GtkTreeView *tree_view = GTK_TREE_VIEW (widget);
   GList *tmp_list;
 
-  /* we validate GTK_TREE_VIEW_NUM_ROWS_PER_IDLE rows initially just to make
-   * sure we have some size. In practice, with a lot of static lists, this
-   * should get a good width.
+  /* we validate some rows initially just to make sure we have some size. 
+   * In practice, with a lot of static lists, this should get a good width.
    */
   do_validate_rows (tree_view, FALSE);
   gtk_tree_view_size_request_columns (tree_view);
@@ -6118,6 +6117,7 @@ do_validate_rows (GtkTreeView *tree_view, gboolean queue_resize)
   gint retval = TRUE;
   GtkTreePath *path = NULL;
   GtkTreeIter iter;
+  GTimer *timer;
   gint i = 0;
 
   gint prev_height = -1;
@@ -6136,6 +6136,9 @@ do_validate_rows (GtkTreeView *tree_view, gboolean queue_resize)
       return FALSE;
     }
 
+  timer = g_timer_new ();
+  g_timer_start (timer);
+
   do
     {
       if (! GTK_RBNODE_FLAG_SET (tree_view->priv->tree->root, GTK_RBNODE_DESCENDANTS_INVALID))
@@ -6213,7 +6216,7 @@ do_validate_rows (GtkTreeView *tree_view, gboolean queue_resize)
 
       i++;
     }
-  while (i < GTK_TREE_VIEW_NUM_ROWS_PER_IDLE);
+  while (g_timer_elapsed (timer, NULL) < GTK_TREE_VIEW_TIME_MS_PER_IDLE / 1000.);
 
   if (!tree_view->priv->fixed_height_check)
    {
@@ -6242,6 +6245,7 @@ do_validate_rows (GtkTreeView *tree_view, gboolean queue_resize)
     }
 
   if (path) gtk_tree_path_free (path);
+  g_timer_destroy (timer);
 
   return retval;
 }