[nautilus/sam/tracker-3] Limit search to specific graphs

[Sam Thursfield <sthursfield src gnome org>]

commit 63bb793f1cb9e32e6897f05a13de0de50c099b29
Author: Sam Thursfield <sam afuera me uk>
Date:   Fri Jul 31 13:25:01 2020 +0200

    Limit search to specific graphs
    
    This is a performance improvement, and also a workaround for
    https://gitlab.gnome.org/GNOME/tracker/-/issues/235.

 src/nautilus-search-engine-tracker.c | 7 +++++++
 1 file changed, 7 insertions(+)
---
diff --git a/src/nautilus-search-engine-tracker.c b/src/nautilus-search-engine-tracker.c
index 4e21173a61..6e5d2a2cca 100644
--- a/src/nautilus-search-engine-tracker.c
+++ b/src/nautilus-search-engine-tracker.c
@@ -346,6 +346,13 @@ nautilus_search_engine_tracker_start (NautilusSearchProvider *provider)
         g_string_append (sparql, " fts:snippet(?urn)");
     }
 
+    g_string_append (sparql, "FROM tracker:FileSystem ");
+
+    if (tracker->fts_enabled)
+    {
+        g_string_append (sparql, "FROM tracker:Documents ");
+    }
+
     g_string_append (sparql,
                      "\nWHERE {"
                      "  ?urn a nfo:FileDataObject;"