annotate data/fileio/TextTest.cpp @ 1881:b504df98c3be

Ensure completion on output model is started at zero, so if it's checked before the input model has become ready and the transform has begun, it is not accidentally reported as complete (affected re-aligning models in Sonic Lineup when replacing the session)

/* -*- 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 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 "TextTest.h"

#include "base/Debug.h"
#include "base/StringBits.h"

#include <QFile>
#include <QXmlInputSource>

bool
TextTest::isApparentTextDocument(FileSource source)
{
    // Return true if the document can be opened and contains some
    // sort of text, either UTF-8 (so it could be Turtle) or another
    // encoding that is recognised as XML

    if (!source.isAvailable()) {
        SVDEBUG << "NOTE: TextTest::isApparentTextDocument: Failed to retrieve document from " << source.getLocation() << endl;
        return false;
    }

    QFile file(source.getLocalFilename());
    if (!file.open(QFile::ReadOnly)) {
        SVDEBUG << "NOTE: TextTest::isApparentTextDocument: Failed to open local file from " << source.getLocalFilename() << endl;
        return false;
    }

    QByteArray bytes = file.read(200);

    if (StringBits::isValidUtf8(std::string(bytes.data()), true)) {
        SVDEBUG << "NOTE: TextTest::isApparentTextDocument: Document appears to be UTF-8" << endl;
        return true; // good enough to be worth trying to parse
    }

    QXmlInputSource xmlSource;
    xmlSource.setData(bytes); // guesses text encoding

    if (xmlSource.data().startsWith("<?xml")) {
        SVDEBUG << "NOTE: TextTest::isApparentTextDocument: Document appears to be XML" << endl;
        return true;
    }

    SVDEBUG << "NOTE: TextTest::isApparentTextDocument: Document is not UTF-8 and is not XML, rejecting" << endl;
    return false;
}