view rdf/RDFImporter.cpp @ 1752:6d09d68165a4 by-id

Further review of ById: make IDs only available when adding a model to the ById store, not by querying the item directly. This means any id encountered in the wild must have been added to the store at some point (even if later released), which simplifies reasoning about lifecycles

/* -*- 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 2008-2012 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 "RDFImporter.h"

#include <map>
#include <vector>

#include <iostream>
#include <cmath>

#include "base/ProgressReporter.h"
#include "base/RealTime.h"

#include "data/model/SparseOneDimensionalModel.h"
#include "data/model/SparseTimeValueModel.h"
#include "data/model/EditableDenseThreeDimensionalModel.h"
#include "data/model/NoteModel.h"
#include "data/model/TextModel.h"
#include "data/model/RegionModel.h"
#include "data/model/ReadOnlyWaveFileModel.h"

#include "data/fileio/FileSource.h"
#include "data/fileio/CachedFile.h"
#include "data/fileio/FileFinder.h"

#include <dataquay/BasicStore.h>
#include <dataquay/PropertyObject.h>

using Dataquay::Uri;
using Dataquay::Node;
using Dataquay::Nodes;
using Dataquay::Triple;
using Dataquay::Triples;
using Dataquay::BasicStore;
using Dataquay::PropertyObject;

class RDFImporterImpl
{
public:
    RDFImporterImpl(QString url, sv_samplerate_t sampleRate);
    virtual ~RDFImporterImpl();

    void setSampleRate(sv_samplerate_t sampleRate) { m_sampleRate = sampleRate; }
    
    bool isOK();
    QString getErrorString() const;

    std::vector<ModelId> getDataModels(ProgressReporter *);

protected:
    BasicStore *m_store;
    Uri expand(QString s) { return m_store->expand(s); }

    QString m_uristring;
    QString m_errorString;
    std::map<QString, ModelId> m_audioModelMap;
    sv_samplerate_t m_sampleRate;

    std::map<ModelId, std::map<QString, float> > m_labelValueMap;

    void getDataModelsAudio(std::vector<ModelId> &, ProgressReporter *);
    void getDataModelsSparse(std::vector<ModelId> &, ProgressReporter *);
    void getDataModelsDense(std::vector<ModelId> &, ProgressReporter *);

    QString getDenseModelTitle(QString featureUri, QString featureTypeUri);

    void getDenseFeatureProperties(QString featureUri,
                                   sv_samplerate_t &sampleRate, int &windowLength,
                                   int &hopSize, int &width, int &height);

    void fillModel(ModelId, sv_frame_t, sv_frame_t,
                   bool, std::vector<float> &, QString);
};

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

RDFImporter::RDFImporter(QString url, sv_samplerate_t sampleRate) :
    m_d(new RDFImporterImpl(url, sampleRate)) 
{
}

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

void
RDFImporter::setSampleRate(sv_samplerate_t sampleRate)
{
    m_d->setSampleRate(sampleRate);
}

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

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

std::vector<ModelId>
RDFImporter::getDataModels(ProgressReporter *r)
{
    return m_d->getDataModels(r);
}

RDFImporterImpl::RDFImporterImpl(QString uri, sv_samplerate_t sampleRate) :
    m_store(new BasicStore),
    m_uristring(uri),
    m_sampleRate(sampleRate)
{
    //!!! retrieve data if remote... then

    m_store->addPrefix("mo", Uri("http://purl.org/ontology/mo/"));
    m_store->addPrefix("af", Uri("http://purl.org/ontology/af/"));
    m_store->addPrefix("dc", Uri("http://purl.org/dc/elements/1.1/"));
    m_store->addPrefix("tl", Uri("http://purl.org/NET/c4dm/timeline.owl#"));
    m_store->addPrefix("event", Uri("http://purl.org/NET/c4dm/event.owl#"));
    m_store->addPrefix("rdfs", Uri("http://www.w3.org/2000/01/rdf-schema#"));

    try {
        QUrl url;
        if (uri.startsWith("file:")) {
            url = QUrl(uri);
        } else {
            url = QUrl::fromLocalFile(uri);
        }
        m_store->import(url, BasicStore::ImportIgnoreDuplicates);
    } catch (std::exception &e) {
        m_errorString = e.what();
    }
}

RDFImporterImpl::~RDFImporterImpl()
{
    delete m_store;
}

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

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

std::vector<ModelId>
RDFImporterImpl::getDataModels(ProgressReporter *reporter)
{
    std::vector<ModelId> models;

    getDataModelsAudio(models, reporter);

    if (m_sampleRate == 0) {
        m_errorString = QString("Invalid audio data model (is audio file format supported?)");
        cerr << m_errorString << endl;
        return models;
    }

    QString error;

    if (m_errorString != "") {
        error = m_errorString;
    }
    m_errorString = "";

    getDataModelsDense(models, reporter);

    if (m_errorString != "") {
        error = m_errorString;
    }
    m_errorString = "";

    getDataModelsSparse(models, reporter);

    if (m_errorString == "" && error != "") {
        m_errorString = error;
    }

    return models;
}

void
RDFImporterImpl::getDataModelsAudio(std::vector<ModelId> &models,
                                    ProgressReporter *reporter)
{
    Nodes sigs = m_store->match
        (Triple(Node(), Uri("a"), expand("mo:Signal"))).subjects();

    foreach (Node sig, sigs) {
        
        Node file = m_store->complete(Triple(Node(), expand("mo:encodes"), sig));
        if (file == Node()) {
            file = m_store->complete(Triple(sig, expand("mo:available_as"), Node()));
        }
        if (file == Node()) {
            cerr << "RDFImporterImpl::getDataModelsAudio: ERROR: No source for signal " << sig << endl;
            continue;
        }

        QString signal = sig.value;
        QString source = file.value;

        SVDEBUG << "NOTE: Seeking signal source \"" << source
                << "\"..." << endl;

        FileSource *fs = new FileSource(source, reporter);
        if (fs->isAvailable()) {
            SVDEBUG << "NOTE: Source is available: Local filename is \""
                    << fs->getLocalFilename()
                    << "\"..." << endl;
        }
            
#ifdef NO_SV_GUI
        if (!fs->isAvailable()) {
            m_errorString = QString("Signal source \"%1\" is not available").arg(source);
            delete fs;
            continue;
        }
#else
        if (!fs->isAvailable()) {
            SVDEBUG << "NOTE: Signal source \"" << source
                    << "\" is not available, using file finder..." << endl;
            FileFinder *ff = FileFinder::getInstance();
            if (ff) {
                QString path = ff->find(FileFinder::AudioFile,
                                        fs->getLocation(),
                                        m_uristring);
                if (path != "") {
                    cerr << "File finder returns: \"" << path
                              << "\"" << endl;
                    delete fs;
                    fs = new FileSource(path, reporter);
                    if (!fs->isAvailable()) {
                        delete fs;
                        m_errorString = QString("Signal source \"%1\" is not available").arg(source);
                        continue;
                    }
                }
            }
        }
#endif

        if (reporter) {
            reporter->setMessage(RDFImporter::tr("Importing audio referenced in RDF..."));
        }
        fs->waitForData();
        auto newModel = std::make_shared<ReadOnlyWaveFileModel>
            (*fs, m_sampleRate);
        if (newModel->isOK()) {
            cerr << "Successfully created wave file model from source at \"" << source << "\"" << endl;
            auto modelId = ModelById::add(newModel);
            models.push_back(modelId);
            m_audioModelMap[signal] = modelId;
            if (m_sampleRate == 0) {
                m_sampleRate = newModel->getSampleRate();
            }
        } else {
            m_errorString = QString("Failed to create wave file model from source at \"%1\"").arg(source);
        }
        delete fs;
    }
}

void
RDFImporterImpl::getDataModelsDense(std::vector<ModelId> &models,
                                    ProgressReporter *reporter)
{
    if (reporter) {
        reporter->setMessage(RDFImporter::tr("Importing dense signal data from RDF..."));
    }

    Nodes sigFeatures = m_store->match
        (Triple(Node(), expand("af:signal_feature"), Node())).objects();

    foreach (Node sf, sigFeatures) {

        if (sf.type != Node::URI && sf.type != Node::Blank) continue;
        
        Node t = m_store->complete(Triple(sf, expand("a"), Node()));
        Node v = m_store->complete(Triple(sf, expand("af:value"), Node()));

        QString feature = sf.value;
        QString type = t.value;
        QString value = v.value;
        
        if (type == "" || value == "") continue;

        sv_samplerate_t sampleRate = 0;
        int windowLength = 0;
        int hopSize = 0;
        int width = 0;
        int height = 0;
        getDenseFeatureProperties
            (feature, sampleRate, windowLength, hopSize, width, height);

        if (sampleRate != 0 && sampleRate != m_sampleRate) {
            cerr << "WARNING: Sample rate in dense feature description does not match our underlying rate -- using rate from feature description" << endl;
        }
        if (sampleRate == 0) sampleRate = m_sampleRate;

        if (hopSize == 0) {
            cerr << "WARNING: Dense feature description does not specify a hop size -- assuming 1" << endl;
            hopSize = 1;
        }

        if (height == 0) {
            cerr << "WARNING: Dense feature description does not specify feature signal dimensions -- assuming one-dimensional (height = 1)" << endl;
            height = 1;
        }

        QStringList values = value.split(' ', QString::SkipEmptyParts);

        if (values.empty()) {
            cerr << "WARNING: Dense feature description does not specify any values!" << endl;
            continue;
        }

        if (height == 1) {

            auto m = std::make_shared<SparseTimeValueModel>
                (sampleRate, hopSize, false);

            for (int j = 0; j < values.size(); ++j) {
                float f = values[j].toFloat();
                Event e(j * hopSize, f, "");
                m->add(e);
            }

            m->setObjectName(getDenseModelTitle(feature, type));
            m->setRDFTypeURI(type);
            models.push_back(ModelById::add(m));

        } else {

            auto m = std::make_shared<EditableDenseThreeDimensionalModel>
                (sampleRate, hopSize, height, 
                 EditableDenseThreeDimensionalModel::NoCompression, false);
            
            EditableDenseThreeDimensionalModel::Column column;

            int x = 0;

            for (int j = 0; j < values.size(); ++j) {
                if (j % height == 0 && !column.empty()) {
                    m->setColumn(x++, column);
                    column.clear();
                }
                column.push_back(values[j].toFloat());
            }

            if (!column.empty()) {
                m->setColumn(x++, column);
            }

            m->setObjectName(getDenseModelTitle(feature, type));
            m->setRDFTypeURI(type);
            models.push_back(ModelById::add(m));
        }
    }
}

QString
RDFImporterImpl::getDenseModelTitle(QString featureUri,
                                    QString featureTypeUri)
{
    Node n = m_store->complete
        (Triple(Uri(featureUri), expand("dc:title"), Node()));

    if (n.type == Node::Literal && n.value != "") {
        SVDEBUG << "RDFImporterImpl::getDenseModelTitle: Title (from signal) \"" << n.value << "\"" << endl;
        return n.value;
    }

    n = m_store->complete
        (Triple(Uri(featureTypeUri), expand("dc:title"), Node()));

    if (n.type == Node::Literal && n.value != "") {
        SVDEBUG << "RDFImporterImpl::getDenseModelTitle: Title (from signal type) \"" << n.value << "\"" << endl;
        return n.value;
    }

    SVDEBUG << "RDFImporterImpl::getDenseModelTitle: No title available for feature <" << featureUri << ">" << endl;
    return {};
}

void
RDFImporterImpl::getDenseFeatureProperties(QString featureUri,
                                           sv_samplerate_t &sampleRate, int &windowLength,
                                           int &hopSize, int &width, int &height)
{
    Node dim = m_store->complete
        (Triple(Uri(featureUri), expand("af:dimensions"), Node()));

    cerr << "Dimensions = \"" << dim.value << "\"" << endl;

    if (dim.type == Node::Literal && dim.value != "") {
        QStringList dl = dim.value.split(" ");
        if (dl.empty()) dl.push_back(dim.value);
        if (dl.size() > 0) height = dl[0].toInt();
        if (dl.size() > 1) width = dl[1].toInt();
    }
    
    // Looking for rate, hop, window from:
    //
    // ?feature mo:time ?time .
    // ?time a tl:Interval .
    // ?time tl:onTimeLine ?timeline .
    // ?map tl:rangeTimeLine ?timeline .
    // ?map tl:sampleRate ?rate .
    // ?map tl:hopSize ?hop .
    // ?map tl:windowLength ?window .

    Node interval = m_store->complete(Triple(Uri(featureUri), expand("mo:time"), Node()));

    if (!m_store->contains(Triple(interval, expand("a"), expand("tl:Interval")))) {
        cerr << "RDFImporterImpl::getDenseFeatureProperties: Feature time node "
             << interval << " is not a tl:Interval" << endl;
        return;
    }

    Node tl = m_store->complete(Triple(interval, expand("tl:onTimeLine"), Node()));
    
    if (tl == Node()) {
        cerr << "RDFImporterImpl::getDenseFeatureProperties: Interval node "
             << interval << " lacks tl:onTimeLine property" << endl;
        return;
    }

    Node map = m_store->complete(Triple(Node(), expand("tl:rangeTimeLine"), tl));
    
    if (map == Node()) {
        cerr << "RDFImporterImpl::getDenseFeatureProperties: No map for "
             << "timeline node " << tl << endl;
    }

    PropertyObject po(m_store, "tl:", map);

    if (po.hasProperty("sampleRate")) {
        sampleRate = po.getProperty("sampleRate").toDouble();
    }
    if (po.hasProperty("hopSize")) {
        hopSize = po.getProperty("hopSize").toInt();
    }
    if (po.hasProperty("windowLength")) {
        windowLength = po.getProperty("windowLength").toInt();
    }

    cerr << "sr = " << sampleRate << ", hop = " << hopSize << ", win = " << windowLength << endl;
}

void
RDFImporterImpl::getDataModelsSparse(std::vector<ModelId> &models,
                                     ProgressReporter *reporter)
{
    if (reporter) {
        reporter->setMessage(RDFImporter::tr("Importing event data from RDF..."));
    }

    /*
      This function is only used for sparse data (for dense data we
      would be in getDataModelsDense instead).

      Our query is intended to retrieve every thing that has a time,
      and every feature type and value associated with a thing that
      has a time.

      We will then need to refine this big bag of results into a set
      of data models.

      Results that have different source signals should go into
      different models.

      Results that have different feature types should go into
      different models.
    */

    Nodes sigs = m_store->match
        (Triple(Node(), expand("a"), expand("mo:Signal"))).subjects();

    // Map from timeline uri to event type to dimensionality to
    // presence of duration to model id.  Whee!
    std::map<QString, std::map<QString, std::map<int, std::map<bool, ModelId> > > >
        modelMap;

    foreach (Node sig, sigs) {
        
        Node interval = m_store->complete(Triple(sig, expand("mo:time"), Node()));
        if (interval == Node()) continue;

        Node tl = m_store->complete(Triple(interval, expand("tl:onTimeLine"), Node()));
        if (tl == Node()) continue;

        Nodes times = m_store->match(Triple(Node(), expand("tl:onTimeLine"), tl)).subjects();
        
        foreach (Node tn, times) {
            
            Nodes timedThings = m_store->match(Triple(Node(), expand("event:time"), tn)).subjects();

            foreach (Node thing, timedThings) {
                
                Node typ = m_store->complete(Triple(thing, expand("a"), Node()));
                if (typ == Node()) continue;

                Node valu = m_store->complete(Triple(thing, expand("af:feature"), Node()));

                QString source = sig.value;
                QString timeline = tl.value;
                QString type = typ.value;
                QString thinguri = thing.value;

                /*
                  For sparse data, the determining factors in deciding
                  what model to use are: Do the features have values?
                  and Do the features have duration?

                  We can run through the results and check off whether
                  we find values and duration for each of the
                  source+type keys, and then run through the
                  source+type keys pushing each of the results into a
                  suitable model.

                  Unfortunately, at this point we do not yet have any
                  actual timing data (time/duration) -- just the time
                  URI.

                  What we _could_ do is to create one of each type of
                  model at the start, for each of the source+type
                  keys, and then push each feature into the relevant
                  model depending on what we find out about it.  Then
                  return only non-empty models.
                */

                QString label = "";
                bool text = (type.contains("Text") || type.contains("text")); // Ha, ha
                bool note = (type.contains("Note") || type.contains("note")); // Guffaw

                if (text) {
                    label = m_store->complete(Triple(thing, expand("af:text"), Node())).value;
                }
                
                if (label == "") {
                    label = m_store->complete(Triple(thing, expand("rdfs:label"), Node())).value;
                }

                RealTime time;
                RealTime duration;

//                bool haveTime = false;
                bool haveDuration = false;

                Node at = m_store->complete(Triple(tn, expand("tl:at"), Node()));

                if (at != Node()) {
                    time = RealTime::fromXsdDuration(at.value.toStdString());
//                    haveTime = true;
                } else {
    //!!! NB we're using rather old terminology for these things, apparently:
    // beginsAt -> start
    // onTimeLine -> timeline

                    Node start = m_store->complete(Triple(tn, expand("tl:beginsAt"), Node()));
                    Node dur = m_store->complete(Triple(tn, expand("tl:duration"), Node()));
                    if (start != Node() && dur != Node()) {
                        time = RealTime::fromXsdDuration
                            (start.value.toStdString());
                        duration = RealTime::fromXsdDuration
                            (dur.value.toStdString());
//                        haveTime = haveDuration = true;
                    }
                }

                QString valuestring = valu.value;
                std::vector<float> values;

                if (valuestring != "") {
                    QStringList vsl = valuestring.split(" ", QString::SkipEmptyParts);
                    for (int j = 0; j < vsl.size(); ++j) {
                        bool success = false;
                        float v = vsl[j].toFloat(&success);
                        if (success) values.push_back(v);
                    }
                }
                
                int dimensions = 1;
                if (values.size() == 1) dimensions = 2;
                else if (values.size() > 1) dimensions = 3;

                ModelId modelId;

                if (modelMap[timeline][type][dimensions].find(haveDuration) ==
                    modelMap[timeline][type][dimensions].end()) {

/*
            SVDEBUG << "Creating new model: source = " << source                      << ", type = " << type << ", dimensions = "
                      << dimensions << ", haveDuration = " << haveDuration
                      << ", time = " << time << ", duration = " << duration
                      << endl;
*/

                    Model *model = nullptr;
                    
                    if (!haveDuration) {

                        if (dimensions == 1) {
                            if (text) {
                                model = new TextModel(m_sampleRate, 1, false);
                            } else {
                                model = new SparseOneDimensionalModel(m_sampleRate, 1, false);
                            }
                        } else if (dimensions == 2) {
                            if (text) {
                                model = new TextModel(m_sampleRate, 1, false);
                            } else {
                                model = new SparseTimeValueModel(m_sampleRate, 1, false);
                            }
                        } else {
                            // We don't have a three-dimensional sparse model,
                            // so use a note model.  We do have some logic (in
                            // extractStructure below) for guessing whether
                            // this should after all have been a dense model,
                            // but it's hard to apply it because we don't have
                            // all the necessary timing data yet... hmm
                            model = new NoteModel(m_sampleRate, 1, false);
                        }

                    } else { // haveDuration

                        if (note || (dimensions > 2)) {
                            model = new NoteModel(m_sampleRate, 1, false);
                        } else {
                            // If our units are frequency or midi pitch, we
                            // should be using a note model... hm
                            model = new RegionModel(m_sampleRate, 1, false);
                        }
                    }

                    model->setRDFTypeURI(type);

                    if (m_audioModelMap.find(source) != m_audioModelMap.end()) {
                        cerr << "source model for " << model << " is " << m_audioModelMap[source] << endl;
                        model->setSourceModel(m_audioModelMap[source]);
                    }

                    QString title = m_store->complete
                        (Triple(typ, expand("dc:title"), Node())).value;
                    if (title == "") {
                        // take it from the end of the event type
                        title = type;
                        title.replace(QRegExp("^.*[/#]"), "");
                    }
                    model->setObjectName(title);

                    modelId = ModelById::add(std::shared_ptr<Model>(model));
                    modelMap[timeline][type][dimensions][haveDuration] = modelId;
                    models.push_back(modelId);
                }

                modelId = modelMap[timeline][type][dimensions][haveDuration];

                if (!modelId.isNone()) {
                    sv_frame_t ftime =
                        RealTime::realTime2Frame(time, m_sampleRate);
                    sv_frame_t fduration =
                        RealTime::realTime2Frame(duration, m_sampleRate);
                    fillModel(modelId, ftime, fduration,
                              haveDuration, values, label);
                }
            }
        }
    }
}

void
RDFImporterImpl::fillModel(ModelId modelId,
                           sv_frame_t ftime,
                           sv_frame_t fduration,
                           bool haveDuration,
                           std::vector<float> &values,
                           QString label)
{
//    SVDEBUG << "RDFImporterImpl::fillModel: adding point at frame " << ftime << endl;

    if (auto sodm = ModelById::getAs<SparseOneDimensionalModel>(modelId)) {
        Event point(ftime, label);
        sodm->add(point);
        return;
    }

    if (auto tm = ModelById::getAs<TextModel>(modelId)) {
        Event e
            (ftime,
             values.empty() ? 0.5f : values[0] < 0.f ? 0.f : values[0] > 1.f ? 1.f : values[0], // I was young and feckless once too
             label);
        tm->add(e);
        return;
    }

    if (auto stvm = ModelById::getAs<SparseTimeValueModel>(modelId)) {
        Event e(ftime, values.empty() ? 0.f : values[0], label);
        stvm->add(e);
        return;
    }

    if (auto nm = ModelById::getAs<NoteModel>(modelId)) {
        if (haveDuration) {
            float value = 0.f, level = 1.f;
            if (!values.empty()) {
                value = values[0];
                if (values.size() > 1) {
                    level = values[1];
                }
            }
            Event e(ftime, value, fduration, level, label);
            nm->add(e);
        } else {
            float value = 0.f, duration = 1.f, level = 1.f;
            if (!values.empty()) {
                value = values[0];
                if (values.size() > 1) {
                    duration = values[1];
                    if (values.size() > 2) {
                        level = values[2];
                    }
                }
            }
            Event e(ftime, value, sv_frame_t(lrintf(duration)),
                        level, label);
            nm->add(e);
        }
        return;
    }

    if (auto rm = ModelById::getAs<RegionModel>(modelId)) {
        float value = 0.f;
        if (values.empty()) {
            // no values? map each unique label to a distinct value
            if (m_labelValueMap[modelId].find(label) == m_labelValueMap[modelId].end()) {
                m_labelValueMap[modelId][label] = rm->getValueMaximum() + 1.f;
            }
            value = m_labelValueMap[modelId][label];
        } else {
            value = values[0];
        }
        if (haveDuration) {
            Event e(ftime, value, fduration, label);
            rm->add(e);
        } else {
            // This won't actually happen -- we only create region models
            // if we do have duration -- but just for completeness
            float duration = 1.f;
            if (!values.empty()) {
                value = values[0];
                if (values.size() > 1) {
                    duration = values[1];
                }
            }
            Event e(ftime, value, sv_frame_t(lrintf(duration)), label);
            rm->add(e);
        }
        return;
    }
            
    cerr << "WARNING: RDFImporterImpl::fillModel: Unknown or unexpected model type" << endl;
    return;
}

RDFImporter::RDFDocumentType
RDFImporter::identifyDocumentType(QString url)
{
    bool haveAudio = false;
    bool haveAnnotations = false;
    bool haveRDF = false;

    BasicStore *store = nullptr;

    // This is not expected to return anything useful, but if it does
    // anything at all then we know we have RDF
    try {
        //!!! non-local document?
        store = BasicStore::load(QUrl(url));
        Triple t = store->matchOnce(Triple());
        if (t != Triple()) haveRDF = true;
    } catch (std::exception &) {
        // nothing; haveRDF will be false so the next bit catches it
    }

    if (!haveRDF) {
        delete store;
        return NotRDF;
    }

    store->addPrefix("mo", Uri("http://purl.org/ontology/mo/"));
    store->addPrefix("event", Uri("http://purl.org/NET/c4dm/event.owl#"));
    store->addPrefix("af", Uri("http://purl.org/ontology/af/"));

    // "MO-conformant" structure for audio files

    Node n = store->complete(Triple(Node(), Uri("a"), store->expand("mo:AudioFile")));
    if (n != Node() && n.type == Node::URI) {

        haveAudio = true;

    } else {

        // Sonic Annotator v0.2 and below used to write this structure
        // (which is not properly in conformance with the Music
        // Ontology)

        Nodes sigs = store->match(Triple(Node(), Uri("a"), store->expand("mo:Signal"))).subjects();
        foreach (Node sig, sigs) {
            Node aa = store->complete(Triple(sig, store->expand("mo:available_as"), Node()));
            if (aa != Node()) {
                haveAudio = true;
                break;
            }
        }
    }

    SVDEBUG << "NOTE: RDFImporter::identifyDocumentType: haveAudio = "
              << haveAudio << endl;

    // can't call complete() with two Nothing nodes
    n = store->matchOnce(Triple(Node(), store->expand("event:time"), Node())).c;
    if (n != Node()) {
        haveAnnotations = true;
    }

    if (!haveAnnotations) {
        // can't call complete() with two Nothing nodes
        n = store->matchOnce(Triple(Node(), store->expand("af:signal_feature"), Node())).c;
        if (n != Node()) {
            haveAnnotations = true;
        }
    }

    SVDEBUG << "NOTE: RDFImporter::identifyDocumentType: haveAnnotations = "
              << haveAnnotations << endl;

    delete store;

    if (haveAudio) {
        if (haveAnnotations) {
            return AudioRefAndAnnotations;
        } else {
            return AudioRef;
        }
    } else {
        if (haveAnnotations) {
            return Annotations;
        } else {
            return OtherRDFDocument;
        }
    }

    return OtherRDFDocument;
}