[gtk+/gtk-3-18] searchenginetracker: Optimize direct/recursive folder lookups

[Carlos Garnacho <carlosg src gnome org>]

commit 3f1e8c6883242f3e8b2ff302f024154b13027c9b
Author: Carlos Garnacho <carlosg gnome org>
Date:   Fri Nov 20 19:04:39 2015 +0100

    searchenginetracker: Optimize direct/recursive folder lookups
    
    tracker:uri-is-descendant/parent has the unfortunate side effect of
    rendering the collation mechanisms in the database useless, so those
    require full table scans to be validated.
    
    Performing these as pure string comparisons will perform much better,
    as those allow the underlying sqlite to rely on its own collation
    to perform the search, which can be significantly faster with many
    elements in the database.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=758407

 gtk/gtksearchenginetracker.c |   23 ++++++++++++++++-------
 1 files changed, 16 insertions(+), 7 deletions(-)
---
diff --git a/gtk/gtksearchenginetracker.c b/gtk/gtksearchenginetracker.c
index 31da508..02e7408 100644
--- a/gtk/gtksearchenginetracker.c
+++ b/gtk/gtksearchenginetracker.c
@@ -227,7 +227,8 @@ sparql_escape_string (const gchar *literal)
 static void
 sparql_append_string_literal (GString     *sparql,
                               const gchar *str,
-                              gboolean     glob)
+                              gboolean     glob,
+                              gboolean     is_dir_uri)
 {
   gchar *s;
 
@@ -236,6 +237,8 @@ sparql_append_string_literal (GString     *sparql,
   g_string_append_c (sparql, '"');
   g_string_append (sparql, s);
 
+  if (is_dir_uri)
+    g_string_append_c (sparql, '/');
   if (glob)
     g_string_append_c (sparql, '*');
   g_string_append_c (sparql, '"');
@@ -250,7 +253,7 @@ sparql_append_string_literal_lower_case (GString     *sparql,
   gchar *s;
 
   s = g_utf8_strdown (str, -1);
-  sparql_append_string_literal (sparql, s, FALSE);
+  sparql_append_string_literal (sparql, s, FALSE, FALSE);
   g_free (s);
 }
 
@@ -347,11 +350,12 @@ gtk_search_engine_tracker_start (GtkSearchEngine *engine)
                          "WHERE {"
                          "  ?urn a nfo:FileDataObject ;"
                          "  tracker:available true ; ");
+                         "  nfo:belongsToContainer ?parent; ");
 
 #ifdef FTS_MATCHING
   /* Using FTS: */
   g_string_append (sparql, "fts:match ");
-  sparql_append_string_literal (sparql, search_text, TRUE);
+  sparql_append_string_literal (sparql, search_text, TRUE, FALSE);
 #endif
 
   g_string_append (sparql, ". FILTER (BOUND(nie:url(?urn)) && ");
@@ -365,11 +369,16 @@ gtk_search_engine_tracker_start (GtkSearchEngine *engine)
       gchar *location_uri = g_file_get_uri (location);
       g_string_append (sparql, " && ");
       if (recursive)
-        g_string_append (sparql, "tracker:uri-is-descendant(");
+        {
+          g_string_append (sparql, "fn:starts-with(nie:url(?urn),");
+          sparql_append_string_literal (sparql, location_uri, FALSE, TRUE);
+          g_string_append (sparql, ")");
+        }
       else
-        g_string_append (sparql, "tracker:uri-is-parent(");
-      sparql_append_string_literal (sparql, location_uri, FALSE);
-      g_string_append (sparql, ",nie:url(?urn))");
+        {
+          g_string_append (sparql, "nie:url(?parent) = ");
+          sparql_append_string_literal (sparql, location_uri, FALSE, FALSE);
+        }
       g_free (location_uri);
     }