diff rdf/SimpleSPARQLQuery.cpp @ 439:beb2948baa77

* Merge revisions 1041 to 1130 from sv-rdf-import branch

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rdf/SimpleSPARQLQuery.cpp	Thu Sep 18 12:09:32 2008 +0000
@@ -0,0 +1,235 @@
+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
+
+/*
+    Sonic Visualiser
+    An audio file viewer and annotation editor.
+    Centre for Digital Music, Queen Mary, University of London.
+    This file copyright 2008 QMUL.
+   
+    This program is free software; you can redistribute it and/or
+    modify it under the terms of the GNU General Public License as
+    published by the Free Software Foundation; either version 2 of the
+    License, or (at your option) any later version.  See the file
+    COPYING included with this distribution for more information.
+*/
+
+#include "SimpleSPARQLQuery.h"
+#include "base/ProgressReporter.h"
+
+#include <rasqal.h>
+
+#include <iostream>
+
+using std::cerr;
+using std::endl;
+
+class SimpleSPARQLQuery::Impl
+{
+public:
+    Impl(QString query);
+    ~Impl();
+
+    void setProgressReporter(ProgressReporter *reporter) { m_reporter = reporter; }
+    bool wasCancelled() const { return m_cancelled; }
+
+    ResultList execute();
+
+    bool isOK() const;
+    QString getErrorString() const;
+
+protected:
+    static void errorHandler(void *, raptor_locator *, const char *);
+
+    static bool m_initialised;
+    
+    QString m_query;
+    QString m_errorString;
+    ProgressReporter *m_reporter;
+    bool m_cancelled;
+};
+
+SimpleSPARQLQuery::SimpleSPARQLQuery(QString query) :
+    m_impl(new Impl(query)) { }
+
+SimpleSPARQLQuery::~SimpleSPARQLQuery() 
+{
+    delete m_impl;
+}
+
+void
+SimpleSPARQLQuery::setProgressReporter(ProgressReporter *reporter)
+{
+    m_impl->setProgressReporter(reporter);
+}
+
+bool
+SimpleSPARQLQuery::wasCancelled() const
+{
+    return m_impl->wasCancelled();
+}
+
+SimpleSPARQLQuery::ResultList
+SimpleSPARQLQuery::execute()
+{
+    return m_impl->execute();
+}
+
+bool
+SimpleSPARQLQuery::isOK() const
+{
+    return m_impl->isOK();
+}
+
+QString
+SimpleSPARQLQuery::getErrorString() const
+{
+    return m_impl->getErrorString();
+}
+
+bool
+SimpleSPARQLQuery::Impl::m_initialised = false;
+
+SimpleSPARQLQuery::Impl::Impl(QString query) :
+    m_query(query),
+    m_reporter(0),
+    m_cancelled(false)
+{
+    //!!! fortunately this global stuff goes away in future rasqal versions
+    if (!m_initialised) {
+        rasqal_init();
+    }
+}
+
+SimpleSPARQLQuery::Impl::~Impl()
+{
+//!!!    rasqal_finish();
+}
+
+bool
+SimpleSPARQLQuery::Impl::isOK() const
+{
+    return (m_errorString == "");
+}
+
+QString
+SimpleSPARQLQuery::Impl::getErrorString() const
+{
+    return m_errorString;
+}
+
+void
+SimpleSPARQLQuery::Impl::errorHandler(void *data, 
+                                      raptor_locator *locator,
+                                      const char *message) 
+{
+    SimpleSPARQLQuery::Impl *impl = (SimpleSPARQLQuery::Impl *)data;
+    
+//    char buffer[256];
+//    raptor_format_locator(buffer, 255, locator);
+//    impl->m_errorString = QString("%1 - %2").arg(buffer).arg(message);
+
+    impl->m_errorString = message;
+
+    cerr << "SimpleSPARQLQuery: ERROR: " << impl->m_errorString.toStdString() << endl;
+}
+
+SimpleSPARQLQuery::ResultList
+SimpleSPARQLQuery::Impl::execute()
+{
+    ResultList list;
+
+    rasqal_query *query = rasqal_new_query("sparql", NULL);
+    if (!query) {
+        m_errorString = "Failed to construct query";
+        cerr << "SimpleSPARQLQuery: ERROR: " << m_errorString.toStdString() << endl;
+        return list;
+    }
+
+    rasqal_query_set_error_handler(query, this, errorHandler);
+    rasqal_query_set_fatal_error_handler(query, this, errorHandler);
+
+    if (rasqal_query_prepare
+        (query, (const unsigned char *)m_query.toUtf8().data(), NULL)) {
+        cerr << "SimpleSPARQLQuery: Failed to prepare query" << endl;
+        rasqal_free_query(query);
+        return list;
+    }
+
+    rasqal_query_results *results = rasqal_query_execute(query);
+    
+//    cerr << "Query executed" << endl;
+
+    if (!results) {
+        cerr << "SimpleSPARQLQuery: RASQAL query failed" << endl;
+        rasqal_free_query(query);
+        return list;
+    }
+
+    if (!rasqal_query_results_is_bindings(results)) {
+        cerr << "SimpleSPARQLQuery: RASQAL query has wrong result type (not bindings)" << endl;
+        rasqal_free_query_results(results);
+        rasqal_free_query(query);
+        return list;
+    }
+    
+    int resultCount = 0;
+    int resultTotal = rasqal_query_results_get_count(results); // probably wrong
+    m_cancelled = false;
+
+    while (!rasqal_query_results_finished(results)) {
+
+        int count = rasqal_query_results_get_bindings_count(results);
+
+        KeyValueMap resultmap;
+
+        for (int i = 0; i < count; ++i) {
+
+            const unsigned char *name =
+                rasqal_query_results_get_binding_name(results, i);
+
+            rasqal_literal *literal =
+                rasqal_query_results_get_binding_value(results, i);
+
+            QString key = (const char *)name;
+
+            if (!literal) {
+                resultmap[key] = Value();
+                continue;
+            }
+
+            ValueType type = LiteralValue;
+            if (literal->type == RASQAL_LITERAL_URI) type = URIValue;
+            else if (literal->type == RASQAL_LITERAL_BLANK) type = BlankValue;
+
+            QString text = (const char *)rasqal_literal_as_string(literal);
+
+            resultmap[key] = Value(type, text);
+        }
+
+        list.push_back(resultmap);
+
+        rasqal_query_results_next(results);
+
+        resultCount++;
+
+        if (m_reporter) {
+            if (resultCount >= resultTotal) {
+                if (m_reporter->isDefinite()) m_reporter->setDefinite(false);
+                m_reporter->setProgress(resultCount);
+            } else {
+                m_reporter->setProgress((resultCount * 100) / resultTotal);
+            }
+
+            if (m_reporter->wasCancelled()) {
+                m_cancelled = true;
+                break;
+            }
+        }
+    }
+
+    rasqal_free_query_results(results);
+    rasqal_free_query(query);
+
+    return list;
+}
+