[tracker/wip/garnacho/sparql1.1: 11/23] libtracker-data: Add SparqlStrBefore/After sqlite functions

[Carlos Garnacho <carlosg src gnome org>]

commit 1d20e38f4cfde75d4ee9d966d4226b40e30cdce2
Author: Carlos Garnacho <carlosg gnome org>
Date:   Tue Jul 28 23:16:13 2015 +0200

    libtracker-data: Add SparqlStrBefore/After sqlite functions
    
    These will be used in STRBEFORE/STRAFTER, as per sparql 1.1

 src/libtracker-data/tracker-db-interface-sqlite.c |   85 +++++++++++++++++++++
 1 files changed, 85 insertions(+), 0 deletions(-)
---
diff --git a/src/libtracker-data/tracker-db-interface-sqlite.c 
b/src/libtracker-data/tracker-db-interface-sqlite.c
index 01fc19d..5e6cada 100644
--- a/src/libtracker-data/tracker-db-interface-sqlite.c
+++ b/src/libtracker-data/tracker-db-interface-sqlite.c
@@ -901,6 +901,84 @@ function_sparql_encode_for_uri (sqlite3_context *context,
        sqlite3_result_text (context, encoded, -1, g_free);
 }
 
+static void
+function_sparql_string_before (sqlite3_context *context,
+                               int              argc,
+                               sqlite3_value   *argv[])
+{
+       const gchar *str, *substr, *loc;
+       gchar *encoded;
+       gint len;
+
+       if (argc != 2) {
+               sqlite3_result_error (context, "Invalid argument count", -1);
+               return;
+       }
+
+       if (sqlite3_value_type (argv[0]) != SQLITE_TEXT ||
+           sqlite3_value_type (argv[1]) != SQLITE_TEXT) {
+               sqlite3_result_error (context, "Invalid argument types", -1);
+               return;
+       }
+
+       str = sqlite3_value_text (argv[0]);
+       substr = sqlite3_value_text (argv[1]);
+       len = strlen (substr);
+
+       if (len == 0) {
+               sqlite3_result_text (context, "", -1, NULL);
+               return;
+       }
+
+       loc = strstr (str, substr);
+
+       if (!loc) {
+               sqlite3_result_text (context, "", -1, NULL);
+               return;
+       }
+
+       sqlite3_result_text (context, g_strndup (str, loc - str), -1, g_free);
+}
+
+static void
+function_sparql_string_after (sqlite3_context *context,
+                              int              argc,
+                              sqlite3_value   *argv[])
+{
+       const gchar *str, *substr, *loc;
+       gchar *encoded;
+       gint len;
+
+       if (argc != 2) {
+               sqlite3_result_error (context, "Invalid argument count", -1);
+               return;
+       }
+
+       if (sqlite3_value_type (argv[0]) != SQLITE_TEXT ||
+           sqlite3_value_type (argv[1]) != SQLITE_TEXT) {
+               sqlite3_result_error (context, "Invalid argument types", -1);
+               return;
+       }
+
+       str = sqlite3_value_text (argv[0]);
+       substr = sqlite3_value_text (argv[1]);
+       len = strlen (substr);
+
+       if (len == 0) {
+               sqlite3_result_text (context, g_strdup (str), -1, g_free);
+               return;
+       }
+
+       loc = strstr (str, substr);
+
+       if (!loc) {
+               sqlite3_result_text (context, "", -1, NULL);
+               return;
+       }
+
+       sqlite3_result_text (context, g_strdup (loc + len), -1, g_free);
+}
+
 static inline int
 stmt_step (sqlite3_stmt *stmt)
 {
@@ -1028,6 +1106,13 @@ open_database (TrackerDBInterface  *db_interface,
                                 db_interface, &function_sparql_encode_for_uri,
                                 NULL, NULL);
 
+       sqlite3_create_function (db_interface->db, "SparqlStringBefore", 2, SQLITE_ANY,
+                                db_interface, &function_sparql_string_before,
+                                NULL, NULL);
+       sqlite3_create_function (db_interface->db, "SparqlStringAfter", 2, SQLITE_ANY,
+                                db_interface, &function_sparql_string_after,
+                                NULL, NULL);
+
        sqlite3_extended_result_codes (db_interface->db, 0);
        sqlite3_busy_timeout (db_interface->db, 100000);
 }