[tracker/blank] SPARQL: Fix URI generation for inserted blank nodes

[Jürg Billeter <juergbi src gnome org>]

commit d0cb4af994043de50ba00baac1308a3cf32fa63c
Author: Jürg Billeter <j bitron ch>
Date:   Wed Nov 25 09:49:03 2009 +0100

    SPARQL: Fix URI generation for inserted blank nodes

 src/libtracker-data/tracker-sparql-query.vala |   44 +++++++++++++-----------
 1 files changed, 24 insertions(+), 20 deletions(-)
---
diff --git a/src/libtracker-data/tracker-sparql-query.vala b/src/libtracker-data/tracker-sparql-query.vala
index 99b25c2..3915577 100644
--- a/src/libtracker-data/tracker-sparql-query.vala
+++ b/src/libtracker-data/tracker-sparql-query.vala
@@ -290,6 +290,21 @@ public class Tracker.SparqlQuery : Object {
 		this.update_extensions = true;
 	}
 
+	string get_uuid_for_name (uchar[] base_uuid, string name) {
+		var checksum = new Checksum (ChecksumType.SHA1);
+		// base UUID, unique per file
+		checksum.update (base_uuid, 16);
+
+		// node ID
+		checksum.update ((uchar[]) name, -1);
+
+		string sha1 = checksum.get_string ();
+
+		// generate name based uuid
+		return "urn:uuid:%.8s-%.4s-%.4s-%.4s-%.12s".printf (
+			sha1, sha1.offset (8), sha1.offset (12), sha1.offset (16), sha1.offset (20));
+	}
+
 	string generate_bnodeid (string? user_bnodeid) {
 		// user_bnodeid is NULL for anonymous nodes
 		if (user_bnodeid == null) {
@@ -304,28 +319,17 @@ public class Tracker.SparqlQuery : Object {
 				}
 			}
 
-			var checksum = new Checksum (ChecksumType.SHA1);
-			// base UUID, unique per file
-			checksum.update (base_uuid, 16);
-
-			while (uri == null) {
-				// node ID
-				checksum.update ((uchar[]) user_bnodeid, -1);
+			uri = get_uuid_for_name (base_uuid, user_bnodeid);
 
-				string sha1 = checksum.get_string ();
-
-				// generate name based uuid
-				uri = "urn:uuid:%.8s-%.4s-%.4s-%.4s-%.12s".printf (
-					sha1, sha1.offset (8), sha1.offset (12), sha1.offset (16), sha1.offset (20));
-
-				if (blank_nodes != null) {
-					if (Data.query_resource_id (uri) > 0) {
-						blank_nodes.insert (user_bnodeid, uri);
-					} else {
-						// uri collision
-						uri = null;
-					}
+			if (blank_nodes != null) {
+				while (Data.query_resource_id (uri) > 0) {
+					// uri collision, generate new UUID
+					uchar[] new_base_uuid = new uchar[16];
+					uuid_generate (new_base_uuid);
+					uri = get_uuid_for_name (new_base_uuid, user_bnodeid);
 				}
+
+				blank_nodes.insert (user_bnodeid, uri);
 			}
 
 			return uri;