view rdf/RDFTransformFactory.cpp @ 492:23945cdd7161

* Update RDF query stuff again so as to set up a temporary datastore
  each time we want to query over an rdf file, instead of using rasqal
  against the file.  Seems the only way to avoid threading and storage
  management issues when trying to load from a single-source file and
  perform queries against our main datastore at the same time.  Maybe.

/* -*- 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 "RDFTransformFactory.h"

#include <map>
#include <vector>

#include <iostream>
#include <cmath>

#include "SimpleSPARQLQuery.h"
#include "PluginRDFIndexer.h"
#include "base/ProgressReporter.h"

#include "transform/TransformFactory.h"

using std::cerr;
using std::endl;

typedef const unsigned char *STR; // redland's expected string type


class RDFTransformFactoryImpl
{
public:
    RDFTransformFactoryImpl(QString url);
    virtual ~RDFTransformFactoryImpl();
    
    bool isOK();
    QString getErrorString() const;

    std::vector<Transform> getTransforms(ProgressReporter *);

protected:
    QString m_urlString;
    QString m_errorString;
    bool setOutput(Transform &, QString);
    bool setParameters(Transform &, QString);
};


QString
RDFTransformFactory::getKnownExtensions()
{
    return "*.rdf *.n3 *.ttl";
}

RDFTransformFactory::RDFTransformFactory(QString url) :
    m_d(new RDFTransformFactoryImpl(url)) 
{
}

RDFTransformFactory::~RDFTransformFactory()
{
    delete m_d;
}

bool
RDFTransformFactory::isOK()
{
    return m_d->isOK();
}

QString
RDFTransformFactory::getErrorString() const
{
    return m_d->getErrorString();
}

std::vector<Transform>
RDFTransformFactory::getTransforms(ProgressReporter *r)
{
    return m_d->getTransforms(r);
}

RDFTransformFactoryImpl::RDFTransformFactoryImpl(QString url) :
    m_urlString(url)
{
}

RDFTransformFactoryImpl::~RDFTransformFactoryImpl()
{
    SimpleSPARQLQuery::closeSingleSource(m_urlString);
}

bool
RDFTransformFactoryImpl::isOK()
{
    return (m_errorString == "");
}

QString
RDFTransformFactoryImpl::getErrorString() const
{
    return m_errorString;
}

std::vector<Transform>
RDFTransformFactoryImpl::getTransforms(ProgressReporter *reporter)
{
    std::vector<Transform> transforms;

    std::map<QString, Transform> uriTransformMap;

    QString query = 
        " PREFIX vamp: <http://purl.org/ontology/vamp/> "

        " SELECT ?transform ?plugin "
        
        " FROM <%2> "

        " WHERE { "
        "   ?transform a vamp:Transform ; "
        "              vamp:plugin ?plugin . "
        " } ";

    SimpleSPARQLQuery transformsQuery
        (SimpleSPARQLQuery::QueryFromSingleSource, query.arg(m_urlString));

    SimpleSPARQLQuery::ResultList transformResults = transformsQuery.execute();

    if (!transformsQuery.isOK()) {
        m_errorString = transformsQuery.getErrorString();
        return transforms;
    }

    if (transformResults.empty()) {
        cerr << "RDFTransformFactory: NOTE: No RDF/TTL transform descriptions found in document at <" << m_urlString.toStdString() << ">" << endl;
        return transforms;
    }

    // There are various queries we need to make that might include
    // data from iether the transform RDF or the model accumulated
    // from plugin descriptions.  For example, the transform RDF may
    // specify the output's true URI, or it might have a blank node or
    // some other URI with the appropriate vamp:identifier included in
    // the file.  To cover both cases, we need to add the file itself
    // into the model and always query the model using the transform
    // URI rather than querying the file itself subsequently.

    SimpleSPARQLQuery::addSourceToModel(m_urlString);

    PluginRDFIndexer *indexer = PluginRDFIndexer::getInstance();

    for (int i = 0; i < transformResults.size(); ++i) {

        SimpleSPARQLQuery::KeyValueMap &result = transformResults[i];

        QString transformUri = result["transform"].value;
        QString pluginUri = result["plugin"].value;

        QString pluginId = indexer->getIdForPluginURI(pluginUri);
        if (pluginId == "") {
            cerr << "RDFTransformFactory: WARNING: Unknown plugin <"
                 << pluginUri.toStdString() << "> for transform <"
                 << transformUri.toStdString() << ">, skipping this transform"
                 << endl;
            continue;
        }

        Transform transform;
        transform.setPluginIdentifier(pluginId);

        if (!setOutput(transform, transformUri)) {
            return transforms;
        }

        if (!setParameters(transform, transformUri)) {
            return transforms;
        }

        uriTransformMap[transformUri] = transform;

        // We have to do this a very long way round, to work around
        // rasqal's current inability to handle correctly more than one
        // OPTIONAL graph in a query

        static const char *optionals[] = {
            "output",
            "program",
            "step_size",
            "block_size",
            "window_type",
            "sample_rate",
            "start", 
            "duration"
        };
        
        for (int j = 0; j < sizeof(optionals)/sizeof(optionals[0]); ++j) {

            QString optional = optionals[j];

            QString queryTemplate = 
                " PREFIX vamp: <http://purl.org/ontology/vamp/> "
                
                " SELECT ?%1 "
                
                " WHERE { "
                "   <%2> vamp:%1 ?%1 "
                " } ";
            
            SimpleSPARQLQuery query
                (SimpleSPARQLQuery::QueryFromModel,
                 queryTemplate.arg(optional).arg(transformUri));
        
            SimpleSPARQLQuery::ResultList results = query.execute();

            if (!query.isOK()) {
                m_errorString = query.getErrorString();
                return transforms;
            }

            if (results.empty()) continue;

            for (int k = 0; k < results.size(); ++k) {

                const SimpleSPARQLQuery::Value &v = results[k][optional];

                if (v.type == SimpleSPARQLQuery::LiteralValue) {
                
                    if (optional == "program") {
                        transform.setProgram(v.value);
                    } else if (optional == "step_size") {
                        transform.setStepSize(v.value.toUInt());
                    } else if (optional == "block_size") {
                        transform.setBlockSize(v.value.toUInt());
                    } else if (optional == "window_type") {
                        cerr << "NOTE: can't handle window type yet (value is \""
                             << v.value.toStdString() << "\")" << endl;
                    } else if (optional == "sample_rate") {
                        transform.setSampleRate(v.value.toFloat());
                    } else if (optional == "start") {
                        transform.setStartTime
                            (RealTime::fromXsdDuration(v.value.toStdString()));
                    } else if (optional == "duration") {
                        transform.setDuration
                            (RealTime::fromXsdDuration(v.value.toStdString()));
                    } else {
                        cerr << "RDFTransformFactory: ERROR: Inconsistent optionals lists (unexpected optional \"" << optional.toStdString() << "\"" << endl;
                    }
                }
            }
        }

        cerr << "RDFTransformFactory: NOTE: Transform is: " << endl;
        cerr << transform.toXmlString().toStdString() << endl;

        transforms.push_back(transform);
    }
        
    return transforms;
}

bool
RDFTransformFactoryImpl::setOutput(Transform &transform,
                                   QString transformUri)
{
    SimpleSPARQLQuery::Value outputValue =
        SimpleSPARQLQuery::singleResultQuery
        (SimpleSPARQLQuery::QueryFromModel,
         QString
         (
             " PREFIX vamp: <http://purl.org/ontology/vamp/> "
             
             " SELECT ?output "

             " WHERE { "
             "   <%1> vamp:output ?output . "
             " } "
             )
         .arg(transformUri),
         "output");
    
    if (outputValue.type == SimpleSPARQLQuery::NoValue) {
        return true;
    }

    if (outputValue.type != SimpleSPARQLQuery::URIValue) {
        m_errorString = "No vamp:output given, or not a URI";
        return false;
    }

    SimpleSPARQLQuery::Value outputIdValue =
        SimpleSPARQLQuery::singleResultQuery
        (SimpleSPARQLQuery::QueryFromModel,
         QString
         (
             " PREFIX vamp: <http://purl.org/ontology/vamp/> "
             
             " SELECT ?output_id "
             
             " WHERE { "
             "   <%1> vamp:identifier ?output_id "
             " } "
             )
         .arg(outputValue.value),
         "output_id");
    
    if (outputIdValue.type != SimpleSPARQLQuery::LiteralValue) {
        m_errorString = "No output vamp:identifier available, or not a literal";
        return false;
    }

    transform.setOutput(outputIdValue.value);

    return true;
}
        

bool
RDFTransformFactoryImpl::setParameters(Transform &transform,
                                       QString transformUri)
{
    SimpleSPARQLQuery paramQuery
        (SimpleSPARQLQuery::QueryFromModel,
         QString
         (
             " PREFIX vamp: <http://purl.org/ontology/vamp/> "
             
             " SELECT ?param_id ?param_value "
             
             " WHERE { "
             "   <%1> vamp:parameter_binding ?binding . "
             "   ?binding vamp:parameter ?param ; "
             "            vamp:value ?param_value . "
             "   ?param vamp:identifier ?param_id "
             " } "
             )
         .arg(transformUri));
    
    SimpleSPARQLQuery::ResultList paramResults = paramQuery.execute();
    
    if (!paramQuery.isOK()) {
        m_errorString = paramQuery.getErrorString();
        return false;
    }
    
    if (paramQuery.wasCancelled()) {
        m_errorString = "Query cancelled";
        return false;
    }
    
    for (int j = 0; j < paramResults.size(); ++j) {
        
        QString paramId = paramResults[j]["param_id"].value;
        QString paramValue = paramResults[j]["param_value"].value;
        
        if (paramId == "" || paramValue == "") continue;
        
        transform.setParameter(paramId, paramValue.toFloat());
    }

    return true;
}