[tracker] libtracker-data: Fix performance regression in SPARQL and Turtle parsers

[Jürg Billeter <juergbi src gnome org>]

commit 5bbd7e9a7803fd797caa6c8b6b709ea0757a9e9c
Author: Jürg Billeter <j bitron ch>
Date:   Thu Feb 10 17:51:33 2011 +0100

    libtracker-data: Fix performance regression in SPARQL and Turtle parsers
    
    string.substring is slow on large strings with Vala < 0.11.6. Revert to
    deprecated string.ndup until we require Vala 0.11.6.

 src/libtracker-data/tracker-sparql-query.vala  |    3 ++-
 src/libtracker-data/tracker-turtle-reader.vala |    3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/src/libtracker-data/tracker-sparql-query.vala b/src/libtracker-data/tracker-sparql-query.vala
index dc312f3..aea63e3 100644
--- a/src/libtracker-data/tracker-sparql-query.vala
+++ b/src/libtracker-data/tracker-sparql-query.vala
@@ -353,7 +353,8 @@ public class Tracker.Sparql.Query : Object {
 
 	internal string get_last_string (int strip = 0) {
 		int last_index = (index + BUFFER_SIZE - 1) % BUFFER_SIZE;
-		return ((string) (tokens[last_index].begin.pos + strip)).substring (0, (int) (tokens[last_index].end.pos - tokens[last_index].begin.pos - 2 * strip));
+		// do not switch to substring for performance reasons until we require Vala 0.11.6
+		return ((string) (tokens[last_index].begin.pos + strip)).ndup ((tokens[last_index].end.pos - tokens[last_index].begin.pos - 2 * strip));
 	}
 
 	void parse_prologue () throws Sparql.Error {
diff --git a/src/libtracker-data/tracker-turtle-reader.vala b/src/libtracker-data/tracker-turtle-reader.vala
index b57235a..aaf0f00 100644
--- a/src/libtracker-data/tracker-turtle-reader.vala
+++ b/src/libtracker-data/tracker-turtle-reader.vala
@@ -134,7 +134,8 @@ public class Tracker.TurtleReader : Object {
 
 	string get_last_string (int strip = 0) {
 		int last_index = (index + BUFFER_SIZE - 1) % BUFFER_SIZE;
-		return ((string) (tokens[last_index].begin.pos + strip)).substring (0, (int) (tokens[last_index].end.pos - tokens[last_index].begin.pos - 2 * strip));
+		// do not switch to substring for performance reasons until we require Vala 0.11.6
+		return ((string) (tokens[last_index].begin.pos + strip)).ndup ((tokens[last_index].end.pos - tokens[last_index].begin.pos - 2 * strip));
 	}
 
 	string resolve_prefixed_name (string prefix, string local_name) throws Sparql.Error {