[tracker/wip/carlosg/deserialize-api: 7/17] libtracker-sparql: Refactor handling of prefix/base in Turtle parsing

[Carlos Garnacho <carlosg src gnome org>]

commit 4c6e7e06b31f63382547098bcdbe57e9b6f7375c
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sun May 8 00:05:20 2022 +0200

    libtracker-sparql: Refactor handling of prefix/base in Turtle parsing
    
    This is handled in the same state that handles subject, but since we
    handle Trig format in the same object, this should happen prior to
    parsing the first GRAPH clause there.
    
    Move this parsing to the initial state, so that it applies for both
    formats the same. This involved changes in parser location handling
    for errors, since the initial state now actually advances the parser.

 .../tracker-deserializer-turtle.c                  | 44 +++++++++++-----------
 1 file changed, 22 insertions(+), 22 deletions(-)
---
diff --git a/src/libtracker-sparql/tracker-deserializer-turtle.c 
b/src/libtracker-sparql/tracker-deserializer-turtle.c
index b3dafa2d2..1670217ef 100644
--- a/src/libtracker-sparql/tracker-deserializer-turtle.c
+++ b/src/libtracker-sparql/tracker-deserializer-turtle.c
@@ -294,6 +294,8 @@ expand_prefix (TrackerDeserializerTurtle  *deserializer,
        expanded = tracker_namespace_manager_expand_uri (namespaces, shortname);
 
        if (g_strcmp0 (expanded, shortname) == 0) {
+               /* Point to beginning of term */
+               deserializer->column_no -= strlen(shortname);
                g_free (expanded);
                g_set_error (error,
                             TRACKER_SPARQL_ERROR,
@@ -491,10 +493,20 @@ tracker_deserializer_turtle_iterate_next (TrackerDeserializerTurtle  *deserializ
 
                switch (deserializer->state) {
                case STATE_INITIAL:
-                       if (deserializer->parse_trig)
-                               deserializer->state = STATE_GRAPH;
-                       else
-                               deserializer->state = STATE_SUBJECT;
+                       if (parse_token (deserializer, "@prefix")) {
+                               if (!handle_prefix (deserializer, error))
+                                       return FALSE;
+                               break;
+                       } else if (parse_token (deserializer, "@base")) {
+                               if (!handle_base (deserializer, error))
+                                       return FALSE;
+                               break;
+                       } else {
+                               if (deserializer->parse_trig)
+                                       deserializer->state = STATE_GRAPH;
+                               else
+                                       deserializer->state = STATE_SUBJECT;
+                       }
                        break;
                case STATE_GRAPH:
                        if (parse_token (deserializer, "graph")) {
@@ -519,22 +531,15 @@ tracker_deserializer_turtle_iterate_next (TrackerDeserializerTurtle  *deserializ
                                             TRACKER_SPARQL_ERROR,
                                             TRACKER_SPARQL_ERROR_PARSE,
                                             "Expected graph block");
+                               return FALSE;
                        }
+
+                       deserializer->state = STATE_SUBJECT;
                        break;
                case STATE_SUBJECT:
                        if (g_buffered_input_stream_get_available (deserializer->buffered_stream) == 0)
                                return FALSE;
 
-                       if (parse_token (deserializer, "@prefix")) {
-                               if (!handle_prefix (deserializer, error))
-                                       return FALSE;
-                               break;
-                       } else if (parse_token (deserializer, "@base")) {
-                               if (!handle_base (deserializer, error))
-                                       return FALSE;
-                               break;
-                       }
-
                        g_clear_pointer (&deserializer->subject, g_free);
 
                        if (parse_token (deserializer, "[")) {
@@ -685,13 +690,14 @@ tracker_deserializer_turtle_iterate_next (TrackerDeserializerTurtle  *deserializ
 
                        if (parse_token (deserializer, ".")) {
                                advance_whitespace_and_comments (deserializer);
-                               deserializer->state = STATE_SUBJECT;
+                               deserializer->state = deserializer->parse_trig ?
+                                       STATE_SUBJECT : STATE_INITIAL;
                        }
 
                        if (deserializer->parse_trig &&
                            parse_token (deserializer, "}")) {
                                advance_whitespace_and_comments (deserializer);
-                               deserializer->state = STATE_GRAPH;
+                               deserializer->state = STATE_INITIAL;
                        }
 
                        /* If we did not advance state, this is a parsing error */
@@ -797,12 +803,6 @@ tracker_deserializer_turtle_get_parser_location (TrackerDeserializer *deserializ
 {
        TrackerDeserializerTurtle *deserializer_ttl = TRACKER_DESERIALIZER_TURTLE (deserializer);
 
-       if (deserializer_ttl->state == STATE_INITIAL) {
-               *line_no = 0;
-               *column_no = 0;
-               return FALSE;
-       }
-
        *line_no = deserializer_ttl->line_no;
        *column_no = deserializer_ttl->column_no;
        return TRUE;