[tracker/wip/carlosg/coverity-fixes: 2/16] libtracker-sparql: Check return values of XML writer functions

[Carlos Garnacho <carlosg src gnome org>]

commit dd885f91c52e144c1474c330f5e9c4bddb15ac34
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sat Oct 23 11:39:46 2021 +0200

    libtracker-sparql: Check return values of XML writer functions
    
    CIDs: #1501112, #1501127, #1501130

 src/libtracker-sparql/tracker-serializer-xml.c | 64 ++++++++++++++++++--------
 1 file changed, 44 insertions(+), 20 deletions(-)
---
diff --git a/src/libtracker-sparql/tracker-serializer-xml.c b/src/libtracker-sparql/tracker-serializer-xml.c
index 057312dfb..d622dfdf2 100644
--- a/src/libtracker-sparql/tracker-serializer-xml.c
+++ b/src/libtracker-sparql/tracker-serializer-xml.c
@@ -78,15 +78,20 @@ serialize_up_to_position (TrackerSerializerXml  *serializer_xml,
 
        if (!serializer_xml->head_printed) {
                xmlTextWriterStartDocument (serializer_xml->writer, "1.0", "UTF-8", NULL);
-               xmlTextWriterStartElement (serializer_xml->writer, XML ("sparql"));
 
-               xmlTextWriterStartElement (serializer_xml->writer, XML ("head"));
+               if (xmlTextWriterStartElement (serializer_xml->writer, XML ("sparql")) < 0)
+                       goto error;
+
+               if (xmlTextWriterStartElement (serializer_xml->writer, XML ("head")) < 0)
+                       goto error;
 
                for (i = 0; i < tracker_sparql_cursor_get_n_columns (cursor); i++) {
                        const gchar *var;
 
                        var = tracker_sparql_cursor_get_variable_name (cursor, i);
-                       xmlTextWriterStartElement (serializer_xml->writer, XML ("variable"));
+
+                       if (xmlTextWriterStartElement (serializer_xml->writer, XML ("variable")) < 0)
+                               goto error;
 
                        if (var && *var) {
                                g_ptr_array_add (serializer_xml->vars,
@@ -96,15 +101,20 @@ serialize_up_to_position (TrackerSerializerXml  *serializer_xml,
                                                 g_strdup_printf ("var%d", i + 1));
                        }
 
-                       xmlTextWriterWriteFormatAttribute (serializer_xml->writer,
-                                                          XML ("name"),
-                                                          "%s",
-                                                          (char *) g_ptr_array_index (serializer_xml->vars, 
i));
+                       if (xmlTextWriterWriteFormatAttribute (serializer_xml->writer,
+                                                              XML ("name"),
+                                                              "%s",
+                                                              (char *) g_ptr_array_index 
(serializer_xml->vars, i)) < 0)
+                               goto error;
+
                        xmlTextWriterEndElement (serializer_xml->writer);
                }
 
                xmlTextWriterEndElement (serializer_xml->writer);
-               xmlTextWriterStartElement (serializer_xml->writer, XML ("results"));
+
+               if (xmlTextWriterStartElement (serializer_xml->writer, XML ("results")) < 0)
+                       goto error;
+
                serializer_xml->head_printed = TRUE;
        }
 
@@ -125,7 +135,8 @@ serialize_up_to_position (TrackerSerializerXml  *serializer_xml,
                        serializer_xml->cursor_started = TRUE;
                }
 
-               xmlTextWriterStartElement (serializer_xml->writer, XML ("result"));
+               if (xmlTextWriterStartElement (serializer_xml->writer, XML ("result")) < 0)
+                       goto error;
 
                for (i = 0; i < tracker_sparql_cursor_get_n_columns (cursor); i++) {
                        const gchar *var, *str, *type = NULL, *datatype = NULL;
@@ -160,25 +171,31 @@ serialize_up_to_position (TrackerSerializerXml  *serializer_xml,
 
                        var = g_ptr_array_index (serializer_xml->vars, i);
 
-                       xmlTextWriterStartElement (serializer_xml->writer, XML ("binding"));
-                       xmlTextWriterWriteFormatAttribute (serializer_xml->writer,
-                                                          XML ("name"),
-                                                          "%s",
-                                                          var);
+                       if (xmlTextWriterStartElement (serializer_xml->writer, XML ("binding")) < 0)
+                               goto error;
+
+                       if (xmlTextWriterWriteFormatAttribute (serializer_xml->writer,
+                                                              XML ("name"),
+                                                              "%s",
+                                                              var) < 0)
+                               goto error;
 
-                       xmlTextWriterStartElement (serializer_xml->writer, XML (type));
+                       if (xmlTextWriterStartElement (serializer_xml->writer, XML (type)) < 0)
+                               goto error;
 
                        if (datatype) {
-                               xmlTextWriterWriteFormatAttribute (serializer_xml->writer,
-                                                                  XML ("datatype"),
-                                                                  "%s",
-                                                                  datatype);
+                               if (xmlTextWriterWriteFormatAttribute (serializer_xml->writer,
+                                                                      XML ("datatype"),
+                                                                      "%s",
+                                                                      datatype) < 0)
+                                       goto error;
                        }
 
                        str = tracker_sparql_cursor_get_string (cursor, i, NULL);
 
                        if (str) {
-                               xmlTextWriterWriteRaw (serializer_xml->writer, XML (str));
+                               if (xmlTextWriterWriteRaw (serializer_xml->writer, XML (str)) < 0)
+                                       goto error;
                        }
 
                        xmlTextWriterEndElement (serializer_xml->writer);
@@ -189,6 +206,13 @@ serialize_up_to_position (TrackerSerializerXml  *serializer_xml,
        }
 
        return TRUE;
+
+ error:
+       g_set_error_literal (error,
+                            TRACKER_SPARQL_ERROR,
+                            TRACKER_SPARQL_ERROR_INTERNAL,
+                            "Error writing XML cursor content");
+       return FALSE;
 }
 
 static gssize