diff rdf/SimpleSPARQLQuery.cpp @ 490:c3fb8258e34d

* Make it possible to import an entire session from an RDF document.
  However, at the moment the timings of events appear to be constrained
  by how far the audio decoder has got through its audio file at the
  time the event is queried -- need to investigate.

--- a/rdf/SimpleSPARQLQuery.cpp	Fri Nov 21 16:12:29 2008 +0000
+++ b/rdf/SimpleSPARQLQuery.cpp	Fri Nov 21 18:03:14 2008 +0000
@@ -31,7 +31,7 @@
 
 #include <redland.h>
 
-//#define DEBUG_SIMPLE_SPARQL_QUERY 1
+#define DEBUG_SIMPLE_SPARQL_QUERY 1
 
 #include <iostream>
 
@@ -115,8 +115,6 @@
 
     librdf_uri *getUri(QString uriString, QString &errorString)
     {
-        QMutexLocker locker(&m_mutex);
-
         if (m_parsedUris.find(uriString) != m_parsedUris.end()) {
             return m_parsedUris[uriString];
         }
@@ -143,7 +141,7 @@
             errorString = QString("Failed to parse RDF from URI \"%1\"")
                 .arg(uriString);
             librdf_free_parser(parser);
-            librdf_free_uri(uri);
+//            librdf_free_uri(uri);
             return 0;
 
         } else {
@@ -315,7 +313,7 @@
 {
     ResultList list;
 
-    m_mutex.lock();
+    QMutexLocker locker(&m_mutex);
 
     if (m_type == QueryFromModel) {
         if (!m_redland) {
@@ -323,7 +321,6 @@
             // added to the model yet (m_redland is only created when
             // addSourceToModel is called)
             cerr << "SimpleSPARQLQuery::execute: NOTE: No sources have been added to data model yet, so no results are possible" << endl;
-            m_mutex.unlock();
             return list;
         }
     }
@@ -336,7 +333,6 @@
                 cerr << "ERROR: SimpleSPARQLQuery::execute: Failed to initialise Rasqal query engine" << endl;
                 delete m_rasqal;
                 m_rasqal = 0;
-                m_mutex.unlock();
                 return list;
             }
         }
@@ -348,8 +344,6 @@
 #endif
     }
 
-    m_mutex.unlock();
-
     if (m_type == QueryFromSingleSource) {
         return executeDirectParser();
     } else {
@@ -426,6 +420,11 @@
             const unsigned char *name =
                 rasqal_query_results_get_binding_name(results, i);
 
+            if (!name) {
+                std::cerr << "WARNING: Result " << i << " of query has no name" << std::endl;
+                continue;
+            }
+
             rasqal_literal *literal =
                 rasqal_query_results_get_binding_value(results, i);
 
@@ -437,10 +436,16 @@
             }
 
             ValueType type = LiteralValue;
-            if (literal->type == RASQAL_LITERAL_URI) type = URIValue;
-            else if (literal->type == RASQAL_LITERAL_BLANK) type = BlankValue;
+            if (literal->type == RASQAL_LITERAL_BLANK) type = BlankValue;
+            else if (literal->type == RASQAL_LITERAL_URI) type = URIValue;
 
-            QString text = (const char *)rasqal_literal_as_string(literal);
+            QString text;
+            const char *lit = (const char *)rasqal_literal_as_string(literal);
+            if (!lit) {
+                std::cerr << "WARNING: Result " << i << " of query has null value" << std::endl;
+            } else {
+                text = lit;
+            }
 
 #ifdef DEBUG_SIMPLE_SPARQL_QUERY
             std::cerr << i << ". " << key.toStdString() << " -> " << text.toStdString() << " (type " << type << ")" << std::endl;
@@ -539,6 +544,11 @@
             const char *name =
                 librdf_query_results_get_binding_name(results, i);
 
+            if (!name) {
+                std::cerr << "WARNING: Result " << i << " of query has no name" << std::endl;
+                continue;
+            }
+
             librdf_node *node =
                 librdf_query_results_get_binding_value(results, i);
 
@@ -556,12 +566,24 @@
 
                 type = URIValue;
                 librdf_uri *uri = librdf_node_get_uri(node);
-                text = (const char *)librdf_uri_as_string(uri);
+                const char *us = (const char *)librdf_uri_as_string(uri);
+
+                if (!us) {
+                    std::cerr << "WARNING: Result " << i << " of query claims URI type, but has null URI" << std::endl;
+                } else {
+                    text = us;
+                }
 
             } else if (librdf_node_is_literal(node)) {
 
                 type = LiteralValue;
-                text = (const char *)librdf_node_get_literal_value(node);
+
+                const char *lit = (const char *)librdf_node_get_literal_value(node);
+                if (!lit) {
+                    std::cerr << "WARNING: Result " << i << " of query claims literal type, but has no literal" << std::endl;
+                } else {
+                    text = lit;
+                }
 
             } else if (librdf_node_is_blank(node)) {
 
@@ -617,7 +639,7 @@
 {
     QString err;
 
-    m_mutex.lock();
+    QMutexLocker locker(&m_mutex);
 
     if (!m_redland) {
         m_redland = new WredlandWorldWrapper();
@@ -625,13 +647,10 @@
             cerr << "ERROR: SimpleSPARQLQuery::addSourceToModel: Failed to initialise Redland datastore" << endl;
             delete m_redland;
             m_redland = 0;
-            m_mutex.unlock();
             return false;
         }
     }
 
-    m_mutex.unlock();
-
     librdf_uri *uri = m_redland->getUri(sourceUri, err);
 
     if (!uri) {