[rygel] tracker: New class for SPARQL search query

[Jens Georg <jensgeorg src gnome org>]

commit 5c69ebca02faa759366487e461812975813f6bc2
Author: Sunil Mohan Adapa <sunil medhas org>
Date:   Thu Dec 9 01:13:32 2010 +0530

    tracker: New class for SPARQL search query
    
    This class helps in generating a SPARQL query meant for searching. It is
    mostly similar to selection query with only minor modifications. It will
    eventually replace the selection query.

 src/plugins/tracker/Makefile.am                    |    1 +
 .../tracker/rygel-tracker-search-query.vala        |  134 ++++++++++++++++++++
 2 files changed, 135 insertions(+), 0 deletions(-)
---
diff --git a/src/plugins/tracker/Makefile.am b/src/plugins/tracker/Makefile.am
index 90a396b..375b356 100644
--- a/src/plugins/tracker/Makefile.am
+++ b/src/plugins/tracker/Makefile.am
@@ -22,6 +22,7 @@ librygel_tracker_la_SOURCES = \
 	rygel-tracker-category-all-container.vala \
 	rygel-tracker-key-chain-map.vala \
 	rygel-tracker-query.vala \
+	rygel-tracker-search-query.vala \
 	rygel-tracker-selection-query.vala \
 	rygel-tracker-deletion-query.vala \
 	rygel-tracker-insertion-query.vala \
diff --git a/src/plugins/tracker/rygel-tracker-search-query.vala b/src/plugins/tracker/rygel-tracker-search-query.vala
new file mode 100644
index 0000000..12ecb66
--- /dev/null
+++ b/src/plugins/tracker/rygel-tracker-search-query.vala
@@ -0,0 +1,134 @@
+/*
+ * Copyright (C) 2010 Nokia Corporation.
+ * Copyright (C) 2010 MediaNet Inh.
+ *
+ * Authors: Zeeshan Ali <zeenix gmail com>
+ *          Sunil Mohan Adapa <sunil medhas org>
+ *
+ * This file is part of Rygel.
+ *
+ * Rygel is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Rygel is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+using GUPnP;
+using Gee;
+
+/**
+ * Represents Tracker SPARQL search query
+ *
+ * FIXME: This does pretty much the same thing as selection query and
+ * should eventually replace it.
+ */
+public class Rygel.Tracker.SearchQuery : Query {
+    public const string ITEM_VARIABLE = "?item";
+    private const string SHARED_FILTER = "(!BOUND(nmm:uPnPShared(" +
+                                         ITEM_VARIABLE + ")) ||" +
+                                         " nmm:uPnPShared(" +
+                                         ITEM_VARIABLE +
+                                         ") = true)";
+
+    public ArrayList<ArrayList<string>> key_chains;
+    public QueryFilter filter;
+    public string order_by;
+    public uint offset;
+    public uint max_count;
+
+    public string[,] result;
+
+    public SearchQuery (ArrayList<ArrayList<string>>? key_chains,
+                        QueryTriplets                 triplets,
+                        QueryFilter?                  filter,
+                        string?                       order_by = null,
+                        uint                          offset = 0,
+                        uint                          max_count = 0,
+                        Cancellable?                  cancellable) {
+        base (triplets);
+
+        this.key_chains = key_chains;
+        this.filter = filter;
+        this.order_by = order_by;
+        this.offset = offset;
+        this.max_count = max_count;
+    }
+
+    public override async void execute (ResourcesIface resources)
+                                        throws IOError {
+        var str = this.to_string_with_count ();
+
+        debug ("Executing SPARQL search query: %s", str);
+
+        this.result = yield resources.sparql_query (str);
+    }
+
+    public async uint get_count (ResourcesIface resources) throws IOError {
+        var str = this.to_string_with_count (true);
+
+        debug ("Executing SPARQL search query for count: %s", str);
+
+        var count_result = yield resources.sparql_query (str);
+
+        return count_result[0,0].to_int ();
+    }
+
+    public override string to_string () {
+        return this.to_string_with_count ();
+    }
+
+    private string to_string_with_count (bool counting = false) {
+        var query = "SELECT";
+
+        if (counting) {
+            query += " COUNT(" + this.ITEM_VARIABLE + ")";
+        } else {
+            query += " " + this.ITEM_VARIABLE;
+            foreach (var chain in this.key_chains) {
+                var variable = this.ITEM_VARIABLE;
+                foreach (var key in chain) {
+                    variable = key + "(" + variable + ")";
+                }
+                query += " " + variable;
+            }
+        }
+
+        query += " WHERE {";
+
+        if (this.triplets != null) {
+            query += triplets.serialize ();
+        }
+
+        if (this.filter != null) {
+            var str = this.filter.to_string ();
+            query += " FILTER (" + this.SHARED_FILTER + " && (" + str + "))";
+        }
+
+        query += " }";
+
+        if (!counting) {
+            if (this.order_by != null) {
+                query += " ORDER BY " + order_by;
+            }
+
+            if (this.offset > 0) {
+                query += " OFFSET " + this.offset.to_string ();
+            }
+
+            if (this.max_count > 0) {
+                query += " LIMIT " + this.max_count.to_string ();
+            }
+        }
+
+        return query;
+    }
+}