[tracker] libtracker-data: Add support for STRBEFORE/STRAFTER builtin functions

[Carlos Garnacho <carlosg src gnome org>]

commit 63d825118d361a4d8683927332b42b30fbfb0a4c
Author: Carlos Garnacho <carlosg gnome org>
Date:   Tue Jul 28 23:34:15 2015 +0200

    libtracker-data: Add support for STRBEFORE/STRAFTER builtin functions
    
    These functions are defined in Sparql 1.1 query language recommendation,
    http://www.w3.org/TR/sparql11-query/#func-strbefore
    http://www.w3.org/TR/sparql11-query/#func-strafter

 src/libtracker-data/tracker-sparql-expression.vala |   22 ++++++++++++++++
 src/libtracker-data/tracker-sparql-scanner.vala    |   26 ++++++++++++++++++-
 2 files changed, 46 insertions(+), 2 deletions(-)
---
diff --git a/src/libtracker-data/tracker-sparql-expression.vala 
b/src/libtracker-data/tracker-sparql-expression.vala
index b0dfb88..afc0d9e 100644
--- a/src/libtracker-data/tracker-sparql-expression.vala
+++ b/src/libtracker-data/tracker-sparql-expression.vala
@@ -1256,6 +1256,28 @@ class Tracker.Sparql.Expression : Object {
                        var result = translate_function (sql, FN_NS + "substring");
                        expect (SparqlTokenType.CLOSE_PARENS);
                        return result;
+               case SparqlTokenType.STRBEFORE:
+                       next ();
+                       expect (SparqlTokenType.OPEN_PARENS);
+                       sql.append ("SparqlStringBefore (");
+                       translate_expression_as_string (sql);
+                       expect (SparqlTokenType.COMMA);
+                       sql.append (",");
+                       translate_expression_as_string (sql);
+                       sql.append (")");
+                       expect (SparqlTokenType.CLOSE_PARENS);
+                       return PropertyType.STRING;
+               case SparqlTokenType.STRAFTER:
+                       next ();
+                       expect (SparqlTokenType.OPEN_PARENS);
+                       sql.append ("SparqlStringAfter (");
+                       translate_expression_as_string (sql);
+                       expect (SparqlTokenType.COMMA);
+                       sql.append (",");
+                       translate_expression_as_string (sql);
+                       sql.append (")");
+                       expect (SparqlTokenType.CLOSE_PARENS);
+                       return PropertyType.STRING;
                case SparqlTokenType.REGEX:
                        translate_regex (sql);
                        query.no_cache = true;
diff --git a/src/libtracker-data/tracker-sparql-scanner.vala b/src/libtracker-data/tracker-sparql-scanner.vala
index f5e919c..51315a4 100644
--- a/src/libtracker-data/tracker-sparql-scanner.vala
+++ b/src/libtracker-data/tracker-sparql-scanner.vala
@@ -405,7 +405,16 @@ public class Tracker.SparqlScanner : Object {
                                break;
                        case 'S':
                        case 's':
-                               if (matches (begin, "SAMETERM")) return SparqlTokenType.SAMETERM;
+                               switch (begin[1]) {
+                               case 'A':
+                               case 'a':
+                                       if (matches (begin, "SAMETERM")) return SparqlTokenType.SAMETERM;
+                                       break;
+                               case 'T':
+                               case 't':
+                                       if (matches (begin, "STRAFTER")) return SparqlTokenType.STRAFTER;
+                                       break;
+                               }
                                break;
                        }
                        break;
@@ -421,7 +430,16 @@ public class Tracker.SparqlScanner : Object {
                                break;
                        case 'S':
                        case 's':
-                               if (matches (begin, "STRSTARTS")) return SparqlTokenType.STRSTARTS;
+                               switch (begin[3]) {
+                               case 'B':
+                               case 'b':
+                                       if (matches (begin, "STRBEFORE")) return SparqlTokenType.STRBEFORE;
+                                       break;
+                               case 'S':
+                               case 's':
+                                       if (matches (begin, "STRSTARTS")) return SparqlTokenType.STRSTARTS;
+                                       break;
+                               }
                                break;
                        }
                        break;
@@ -1012,6 +1030,8 @@ public enum Tracker.SparqlTokenType {
        SILENT,
        STAR,
        STR,
+       STRAFTER,
+       STRBEFORE,
        STRENDS,
        STRING_LITERAL1,
        STRING_LITERAL2,
@@ -1119,6 +1139,8 @@ public enum Tracker.SparqlTokenType {
                case SILENT: return "`SILENT'";
                case STAR: return "`*'";
                case STR: return "`STR'";
+               case STRAFTER: return "`STRAFTER'";
+               case STRBEFORE: return "`STRBEFORE'";
                case STRENDS: return "`STRENDS'";
                case STRING_LITERAL1: return "string literal";
                case STRING_LITERAL2: return "string literal";