annotate data/fileio/FileSource.cpp @ 360:ac300d385ab2

* Various fixes to object lifetime management, particularly in the spectrum
  layer and for notification of main model deletion.
  The main purpose of this is to improve the behaviour of the spectrum, but I
  think it may also help with #1840922 Various crashes in Layer Summary window.

/* -*- 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 2007 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 "FileSource.h"
#include "ProgressPrinter.h"

#include "base/TempDirectory.h"
#include "base/Exceptions.h"

#include <QHttp>
#include <QFtp>
#include <QFileInfo>
#include <QDir>
#include <QApplication>
#include <QProgressDialog>
#include <QHttpResponseHeader>

#include <iostream>

#define DEBUG_FILE_SOURCE 1

int
FileSource::m_count = 0;

QMutex
FileSource::m_fileCreationMutex;

FileSource::RemoteRefCountMap
FileSource::m_refCountMap;

FileSource::RemoteLocalMap
FileSource::m_remoteLocalMap;

QMutex
FileSource::m_mapMutex;

FileSource::FileSource(QString fileOrUrl, ShowProgressType progressType) :
    m_url(fileOrUrl),
    m_ftp(0),
    m_http(0),
    m_localFile(0),
    m_ok(false),
    m_lastStatus(0),
    m_remote(isRemote(fileOrUrl)),
    m_done(false),
    m_leaveLocalFile(false),
    m_progressType(progressType),
    m_progressPrinter(0),
    m_progressDialog(0),
    m_progressShowTimer(this),
    m_refCounted(false)
{
#ifdef DEBUG_FILE_SOURCE
    std::cerr << "FileSource::FileSource(" << fileOrUrl.toStdString() << ")" << std::endl;
#endif

    if (!canHandleScheme(m_url)) {
        std::cerr << "FileSource::FileSource: ERROR: Unsupported scheme in URL \"" << m_url.toString().toStdString() << "\"" << std::endl;
        m_errorString = tr("Unsupported scheme in URL");
        return;
    }

    init();

    if (isRemote() &&
        (fileOrUrl.contains('%') ||
         fileOrUrl.contains("--"))) { // for IDNA

        waitForStatus();

        if (!isAvailable()) {

            // The URL was created on the assumption that the string
            // was human-readable.  Let's try again, this time
            // assuming it was already encoded.
            std::cerr << "FileSource::FileSource: Failed to retrieve URL \""
                      << fileOrUrl.toStdString() 
                      << "\" as human-readable URL; "
                      << "trying again treating it as encoded URL"
                      << std::endl;

            // even though our cache file doesn't exist (because the
            // resource was 404), we still need to ensure we're no
            // longer associating a filename with this url in the
            // refcount map -- or createCacheFile will think we've
            // already done all the work and no request will be sent
            deleteCacheFile();

            m_url.setEncodedUrl(fileOrUrl.toAscii());

            m_ok = false;
            m_done = false;
            m_lastStatus = 0;
            init();
        }
    }

    if (!isRemote()) {
        emit statusAvailable();
        emit ready();
    }
}

FileSource::FileSource(QUrl url, ShowProgressType progressType) :
    m_url(url),
    m_ftp(0),
    m_http(0),
    m_localFile(0),
    m_ok(false),
    m_lastStatus(0),
    m_remote(isRemote(url.toString())),
    m_done(false),
    m_leaveLocalFile(false),
    m_progressType(progressType),
    m_progressPrinter(0),
    m_progressDialog(0),
    m_progressShowTimer(this),
    m_refCounted(false)
{
#ifdef DEBUG_FILE_SOURCE
    std::cerr << "FileSource::FileSource(" << url.toString().toStdString() << ") [as url]" << std::endl;
#endif

    if (!canHandleScheme(m_url)) {
        std::cerr << "FileSource::FileSource: ERROR: Unsupported scheme in URL \"" << m_url.toString().toStdString() << "\"" << std::endl;
        m_errorString = tr("Unsupported scheme in URL");
        return;
    }

    init();
}

FileSource::FileSource(const FileSource &rf) :
    QObject(),
    m_url(rf.m_url),
    m_ftp(0),
    m_http(0),
    m_localFile(0),
    m_ok(rf.m_ok),
    m_lastStatus(rf.m_lastStatus),
    m_remote(rf.m_remote),
    m_done(false),
    m_leaveLocalFile(false),
    m_progressType(rf.m_progressType),
    m_progressPrinter(0),
    m_progressDialog(0),
    m_progressShowTimer(0),
    m_refCounted(false)
{
#ifdef DEBUG_FILE_SOURCE
    std::cerr << "FileSource::FileSource(" << m_url.toString().toStdString() << ") [copy ctor]" << std::endl;
#endif

    if (!canHandleScheme(m_url)) {
        std::cerr << "FileSource::FileSource: ERROR: Unsupported scheme in URL \"" << m_url.toString().toStdString() << "\"" << std::endl;
        m_errorString = tr("Unsupported scheme in URL");
        return;
    }

    if (!isRemote()) {
        m_localFilename = rf.m_localFilename;
    } else {
        QMutexLocker locker(&m_mapMutex);
#ifdef DEBUG_FILE_SOURCE
        std::cerr << "FileSource::FileSource(copy ctor): ref count is "
                  << m_refCountMap[m_url] << std::endl;
#endif
        if (m_refCountMap[m_url] > 0) {
            m_refCountMap[m_url]++;
#ifdef DEBUG_FILE_SOURCE
            std::cerr << "raised it to " << m_refCountMap[m_url] << std::endl;
#endif
            m_localFilename = m_remoteLocalMap[m_url];
            m_refCounted = true;
        } else {
            m_ok = false;
            m_lastStatus = 404;
        }
    }

    m_done = true;
}

FileSource::~FileSource()
{
#ifdef DEBUG_FILE_SOURCE
    std::cerr << "FileSource(" << m_url.toString().toStdString() << ")::~FileSource" << std::endl;
#endif

    cleanup();

    if (isRemote() && !m_leaveLocalFile) deleteCacheFile();
}

void
FileSource::init()
{
    if (!isRemote()) {
#ifdef DEBUG_FILE_SOURCE
        std::cerr << "FileSource::init: Not a remote URL" << std::endl;
#endif
        bool literal = false;
        m_localFilename = m_url.toLocalFile();
        if (m_localFilename == "") {
            // QUrl may have mishandled the scheme (e.g. in a DOS path)
            m_localFilename = m_url.toString();
            literal = true;
        }
#ifdef DEBUG_FILE_SOURCE
        std::cerr << "FileSource::init: URL translates to local filename \""
                  << m_localFilename.toStdString() << "\"" << std::endl;
#endif
        m_ok = true;
        m_lastStatus = 200;

        if (!QFileInfo(m_localFilename).exists()) {
            if (literal) {
                m_lastStatus = 404;
            } else {
                // Again, QUrl may have been mistreating us --
                // e.g. dropping a part that looks like query data
                m_localFilename = m_url.toString();
                literal = true;
                if (!QFileInfo(m_localFilename).exists()) {
                    m_lastStatus = 404;
                }
            }
        }

        m_done = true;
        return;
    }

    if (createCacheFile()) {
#ifdef DEBUG_FILE_SOURCE
        std::cerr << "FileSource::init: Already have this one" << std::endl;
#endif
        m_ok = true;
        if (!QFileInfo(m_localFilename).exists()) {
            m_lastStatus = 404;
        } else {
            m_lastStatus = 200;
        }
        m_done = true;
        return;
    }

    if (m_localFilename == "") return;
    m_localFile = new QFile(m_localFilename);
    m_localFile->open(QFile::WriteOnly);

    QString scheme = m_url.scheme().toLower();

#ifdef DEBUG_FILE_SOURCE
    std::cerr << "FileSource::init: Don't have local copy of \""
              << m_url.toString().toStdString() << "\", retrieving" << std::endl;
#endif

    if (scheme == "http") {
        initHttp();
        std::cerr << "FileSource: initHttp succeeded" << std::endl;
    } else if (scheme == "ftp") {
        initFtp();
    } else {
        m_remote = false;
        m_ok = false;
    }

    if (m_ok) {
        
        QMutexLocker locker(&m_mapMutex);

        if (m_refCountMap[m_url] > 0) {
            // someone else has been doing the same thing at the same time,
            // but has got there first
            cleanup();
            m_refCountMap[m_url]++;
#ifdef DEBUG_FILE_SOURCE
            std::cerr << "FileSource::init: Another FileSource has got there first, abandoning our download and using theirs" << std::endl;
#endif
            m_localFilename = m_remoteLocalMap[m_url];
            m_refCounted = true;
            m_ok = true;
            if (!QFileInfo(m_localFilename).exists()) {
                m_lastStatus = 404;
            }
            m_done = true;
            return;
        }

        m_remoteLocalMap[m_url] = m_localFilename;
        m_refCountMap[m_url]++;
        m_refCounted = true;

        switch (m_progressType) {

        case ProgressNone: break;

        case ProgressDialog:
            m_progressDialog = new QProgressDialog
                (tr("Downloading %1...").arg(m_url.toString()),
                 tr("Cancel"), 0, 100);
            m_progressDialog->hide();
            connect(&m_progressShowTimer, SIGNAL(timeout()),
                    this, SLOT(showProgressDialog()));
            connect(m_progressDialog, SIGNAL(canceled()),
                    this, SLOT(cancelled()));
            m_progressShowTimer.setSingleShot(true);
            m_progressShowTimer.start(2000);
            break;

        case ProgressToConsole:
            m_progressPrinter = new ProgressPrinter(tr("Downloading..."));
            connect(this, SIGNAL(progress(int)),
                    m_progressPrinter, SLOT(progress(int)));
            break;
        }
    }
}

void
FileSource::initHttp()
{
    m_ok = true;
    m_http = new QHttp(m_url.host(), m_url.port(80));
    connect(m_http, SIGNAL(done(bool)), this, SLOT(done(bool)));
    connect(m_http, SIGNAL(dataReadProgress(int, int)),
            this, SLOT(dataReadProgress(int, int)));
    connect(m_http, SIGNAL(responseHeaderReceived(const QHttpResponseHeader &)),
            this, SLOT(httpResponseHeaderReceived(const QHttpResponseHeader &)));

    // I don't quite understand this.  url.path() returns a path
    // without percent encoding; for example, spaces appear as
    // literal spaces.  This generally won't work if sent to the
    // server directly.  You can retrieve a correctly encoded URL
    // from QUrl using url.toEncoded(), but that gives you the
    // whole URL; there doesn't seem to be any way to retrieve
    // only an encoded path.  Furthermore there doesn't seem to be
    // any way to convert a retrieved path into an encoded path
    // without explicitly specifying that you don't want the path
    // separators ("/") to be encoded.  (Besides being painful to
    // manage, I don't see how this can work correctly in any case
    // where a percent-encoded "/" is supposed to appear within a
    // path element?)  There also seems to be no way to retrieve
    // the path plus query string, i.e. everything that I need to
    // send to the HTTP server.  And no way for QHttp to take a
    // QUrl argument.  I'm obviously missing something.

    // So, two ways to do this: query the bits from the URL,
    // encode them individually, and glue them back together
    // again...
/*
    QString path = QUrl::toPercentEncoding(m_url.path(), "/");
    QList<QPair<QString, QString> > query = m_url.queryItems();
    if (!query.empty()) {
        QStringList q2;
        for (QList<QPair<QString, QString> >::iterator i = query.begin();
             i != query.end(); ++i) {
            q2.push_back(QString("%1=%3")
                         .arg(QString(QUrl::toPercentEncoding(i->first)))
                         .arg(QString(QUrl::toPercentEncoding(i->second))));
        }
        path = QString("%1%2%3")
            .arg(path).arg("?")
            .arg(q2.join("&"));
    }
*/

    // ...or, much simpler but relying on knowledge about the
    // scheme://host/path/path/query etc format of the URL, we can
    // get the whole URL ready-encoded and then split it on "/" as
    // appropriate...
        
    QString path = "/" + QString(m_url.toEncoded()).section('/', 3);

#ifdef DEBUG_FILE_SOURCE
    std::cerr << "FileSource: path is \""
              << path.toStdString() << "\"" << std::endl;
#endif
        
    m_http->get(path, m_localFile);
}

void
FileSource::initFtp()
{
    m_ok = true;
    m_ftp = new QFtp;
    connect(m_ftp, SIGNAL(done(bool)), this, SLOT(done(bool)));
    connect(m_ftp, SIGNAL(commandFinished(int, bool)),
            this, SLOT(ftpCommandFinished(int, bool)));
    connect(m_ftp, SIGNAL(dataTransferProgress(qint64, qint64)),
            this, SLOT(dataTransferProgress(qint64, qint64)));
    m_ftp->connectToHost(m_url.host(), m_url.port(21));
    
    QString username = m_url.userName();
    if (username == "") {
        username = "anonymous";
    }
    
    QString password = m_url.password();
    if (password == "") {
        password = QString("%1@%2").arg(getenv("USER")).arg(getenv("HOST"));
    }
    
    m_ftp->login(username, password);
    
    QString dirpath = m_url.path().section('/', 0, -2);
    QString filename = m_url.path().section('/', -1);
    
    if (dirpath == "") dirpath = "/";
    m_ftp->cd(dirpath);
    m_ftp->get(filename, m_localFile);
}

void
FileSource::cleanup()
{
    m_done = true;
    if (m_http) {
        QHttp *h = m_http;
        m_http = 0;
        h->abort();
        h->deleteLater();
    }
    if (m_ftp) {
        QFtp *f = m_ftp;
        m_ftp = 0;
        f->abort();
        f->deleteLater();
    }
    delete m_progressDialog;
    m_progressDialog = 0;
    delete m_progressPrinter;
    m_progressPrinter = 0;
    delete m_localFile; // does not actually delete the file
    m_localFile = 0;
}

bool
FileSource::isRemote(QString fileOrUrl)
{
    // Note that a "scheme" with length 1 is probably a DOS drive letter
    QString scheme = QUrl(fileOrUrl).scheme().toLower();
    if (scheme == "" || scheme == "file" || scheme.length() == 1) return false;
    return true;
}

bool
FileSource::canHandleScheme(QUrl url)
{
    // Note that a "scheme" with length 1 is probably a DOS drive letter
    QString scheme = url.scheme().toLower();
    return (scheme == "http" || scheme == "ftp" ||
            scheme == "file" || scheme == "" || scheme.length() == 1);
}

bool
FileSource::isAvailable()
{
    waitForStatus();
    bool available = true;
    if (!m_ok) available = false;
    else available = (m_lastStatus / 100 == 2);
#ifdef DEBUG_FILE_SOURCE
    std::cerr << "FileSource::isAvailable: " << (available ? "yes" : "no")
              << std::endl;
#endif
    return available;
}

void
FileSource::waitForStatus()
{
    while (m_ok && (!m_done && m_lastStatus == 0)) {
//        std::cerr << "waitForStatus: processing (last status " << m_lastStatus << ")" << std::endl;
        QApplication::processEvents();
    }
}

void
FileSource::waitForData()
{
    while (m_ok && !m_done) {
//        std::cerr << "FileSource::waitForData: calling QApplication::processEvents" << std::endl;
        QApplication::processEvents();
    }
}

void
FileSource::setLeaveLocalFile(bool leave)
{
    m_leaveLocalFile = leave;
}

bool
FileSource::isOK() const
{
    return m_ok;
}

bool
FileSource::isDone() const
{
    return m_done;
}

bool
FileSource::isRemote() const
{
    return m_remote;
}

QString
FileSource::getLocation() const
{
    return m_url.toString();
}

QString
FileSource::getLocalFilename() const
{
    return m_localFilename;
}

QString
FileSource::getContentType() const
{
    return m_contentType;
}

QString
FileSource::getExtension() const
{
    if (m_localFilename != "") {
        return QFileInfo(m_localFilename).suffix().toLower();
    } else {
        return QFileInfo(m_url.toLocalFile()).suffix().toLower();
    }
}

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

void
FileSource::dataReadProgress(int done, int total)
{
    dataTransferProgress(done, total);
}

void
FileSource::httpResponseHeaderReceived(const QHttpResponseHeader &resp)
{
    m_lastStatus = resp.statusCode();
    if (m_lastStatus / 100 >= 4) {
        m_errorString = QString("%1 %2")
            .arg(resp.statusCode()).arg(resp.reasonPhrase());
#ifdef DEBUG_FILE_SOURCE
        std::cerr << "FileSource::responseHeaderReceived: "
                  << m_errorString.toStdString() << std::endl;
#endif
    } else {
#ifdef DEBUG_FILE_SOURCE
        std::cerr << "FileSource::responseHeaderReceived: "
                  << m_lastStatus << std::endl;
#endif
        if (resp.hasContentType()) m_contentType = resp.contentType();
    }
    emit statusAvailable();
}

void
FileSource::ftpCommandFinished(int id, bool error)
{
#ifdef DEBUG_FILE_SOURCE
    std::cerr << "FileSource::ftpCommandFinished(" << id << ", " << error << ")" << std::endl;
#endif

    if (!m_ftp) return;

    QFtp::Command command = m_ftp->currentCommand();

    if (!error) {
#ifdef DEBUG_FILE_SOURCE
        std::cerr << "FileSource::ftpCommandFinished: success for command "
                  << command << std::endl;
#endif
        return;
    }

    if (command == QFtp::ConnectToHost) {
        m_errorString = tr("Failed to connect to FTP server");
    } else if (command == QFtp::Login) {
        m_errorString = tr("Login failed");
    } else if (command == QFtp::Cd) {
        m_errorString = tr("Failed to change to correct directory");
    } else if (command == QFtp::Get) {
        m_errorString = tr("FTP download aborted");
    }

    m_lastStatus = 400; // for done()
}

void
FileSource::dataTransferProgress(qint64 done, qint64 total)
{
    int percent = int((double(done) / double(total)) * 100.0 - 0.1);
    emit progress(percent);

    if (!m_progressDialog) return;

    if (percent > 0) {
        m_progressDialog->setValue(percent);
        m_progressDialog->show();
    }
}

void
FileSource::cancelled()
{
    m_done = true;
    cleanup();

    m_ok = false;
    m_errorString = tr("Download cancelled");
}

void
FileSource::done(bool error)
{
    emit progress(100);

#ifdef DEBUG_FILE_SOURCE
    std::cerr << "FileSource::done(" << error << ")" << std::endl;
#endif

    if (m_done) return;

    if (error) {
        if (m_http) {
            m_errorString = m_http->errorString();
        } else if (m_ftp) {
            m_errorString = m_ftp->errorString();
        }
    }

    if (m_lastStatus / 100 >= 4) {
        error = true;
    }

    cleanup();

    if (!error) {
        QFileInfo fi(m_localFilename);
        if (!fi.exists()) {
            m_errorString = tr("Failed to create local file %1").arg(m_localFilename);
            error = true;
        } else if (fi.size() == 0) {
            m_errorString = tr("File contains no data!");
            error = true;
        }
    }

    if (error) {
#ifdef DEBUG_FILE_SOURCE
        std::cerr << "FileSource::done: error is " << error << ", deleting cache file" << std::endl;
#endif
        deleteCacheFile();
    }

    m_ok = !error;
    m_done = true;
    emit ready();
}

void
FileSource::deleteCacheFile()
{
#ifdef DEBUG_FILE_SOURCE
    std::cerr << "FileSource::deleteCacheFile(\"" << m_localFilename.toStdString() << "\")" << std::endl;
#endif

    cleanup();

    if (m_localFilename == "") {
        return;
    }

    if (!isRemote()) {
#ifdef DEBUG_FILE_SOURCE
        std::cerr << "not a cache file" << std::endl;
#endif
        return;
    }

    if (m_refCounted) {

        QMutexLocker locker(&m_mapMutex);
        m_refCounted = false;

        if (m_refCountMap[m_url] > 0) {
            m_refCountMap[m_url]--;
#ifdef DEBUG_FILE_SOURCE
            std::cerr << "reduced ref count to " << m_refCountMap[m_url] << std::endl;
#endif
            if (m_refCountMap[m_url] > 0) {
                m_done = true;
                return;
            }
        }
    }

    m_fileCreationMutex.lock();

    if (!QFile(m_localFilename).remove()) {
#ifdef DEBUG_FILE_SOURCE
        std::cerr << "FileSource::deleteCacheFile: ERROR: Failed to delete file \"" << m_localFilename.toStdString() << "\"" << std::endl;
#endif
    } else {
#ifdef DEBUG_FILE_SOURCE
        std::cerr << "FileSource::deleteCacheFile: Deleted cache file \"" << m_localFilename.toStdString() << "\"" << std::endl;
#endif
        m_localFilename = "";
    }

    m_fileCreationMutex.unlock();

    m_done = true;
}

void
FileSource::showProgressDialog()
{
    if (m_progressDialog) m_progressDialog->show();
}

bool
FileSource::createCacheFile()
{
    {
        QMutexLocker locker(&m_mapMutex);

#ifdef DEBUG_FILE_SOURCE
        std::cerr << "FileSource::createCacheFile: refcount is " << m_refCountMap[m_url] << std::endl;
#endif

        if (m_refCountMap[m_url] > 0) {
            m_refCountMap[m_url]++;
            m_localFilename = m_remoteLocalMap[m_url];
#ifdef DEBUG_FILE_SOURCE
            std::cerr << "raised it to " << m_refCountMap[m_url] << std::endl;
#endif
            m_refCounted = true;
            return true;
        }
    }

    QDir dir;
    try {
        dir = TempDirectory::getInstance()->getSubDirectoryPath("download");
    } catch (DirectoryCreationFailed f) {
#ifdef DEBUG_FILE_SOURCE
        std::cerr << "FileSource::createCacheFile: ERROR: Failed to create temporary directory: " << f.what() << std::endl;
#endif
        return "";
    }

    QString filepart = m_url.path().section('/', -1, -1,
                                            QString::SectionSkipEmpty);

    QString extension = filepart.section('.', -1);
    QString base = filepart;
    if (extension != "") {
        base = base.left(base.length() - extension.length() - 1);
    }
    if (base == "") base = "remote";

    QString filename;

    if (extension == "") {
        filename = base;
    } else {
        filename = QString("%1.%2").arg(base).arg(extension);
    }

    QString filepath(dir.filePath(filename));

#ifdef DEBUG_FILE_SOURCE
    std::cerr << "FileSource::createCacheFile: URL is \"" << m_url.toString().toStdString() << "\", dir is \"" << dir.path().toStdString() << "\", base \"" << base.toStdString() << "\", extension \"" << extension.toStdString() << "\", filebase \"" << filename.toStdString() << "\", filename \"" << filepath.toStdString() << "\"" << std::endl;
#endif

    QMutexLocker fcLocker(&m_fileCreationMutex);

    ++m_count;

    if (QFileInfo(filepath).exists() ||
        !QFile(filepath).open(QFile::WriteOnly)) {

#ifdef DEBUG_FILE_SOURCE
        std::cerr << "FileSource::createCacheFile: Failed to create local file \""
                  << filepath.toStdString() << "\" for URL \""
                  << m_url.toString().toStdString() << "\" (or file already exists): appending suffix instead" << std::endl;
#endif

        if (extension == "") {
            filename = QString("%1_%2").arg(base).arg(m_count);
        } else {
            filename = QString("%1_%2.%3").arg(base).arg(m_count).arg(extension);
        }
        filepath = dir.filePath(filename);

        if (QFileInfo(filepath).exists() ||
            !QFile(filepath).open(QFile::WriteOnly)) {

#ifdef DEBUG_FILE_SOURCE
            std::cerr << "FileSource::createCacheFile: ERROR: Failed to create local file \""
                      << filepath.toStdString() << "\" for URL \""
                      << m_url.toString().toStdString() << "\" (or file already exists)" << std::endl;
#endif

            return "";
        }
    }

#ifdef DEBUG_FILE_SOURCE
    std::cerr << "FileSource::createCacheFile: url "
              << m_url.toString().toStdString() << " -> local filename "
              << filepath.toStdString() << std::endl;
#endif
    
    m_localFilename = filepath;

    return false;
}