view data/fileio/RemoteFile.cpp @ 316:3a6725f285d6

* Make RemoteFile far more pervasive, and use it for local files as well
  so that we can handle both transparently.  Make it shallow copy with
  reference counting, so it can be used by value without having to worry
  about the cache file lifetime.  Use RemoteFile for MainWindow file-open
  functions, etc

/* -*- 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 "RemoteFile.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>

int
RemoteFile::m_count = 0;

QMutex
RemoteFile::m_fileCreationMutex;

RemoteFile::RemoteRefCountMap
RemoteFile::m_refCountMap;

RemoteFile::RemoteLocalMap
RemoteFile::m_remoteLocalMap;

QMutex
RemoteFile::m_mapMutex;

RemoteFile::RemoteFile(QString fileOrUrl, bool showProgress) :
    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_progressDialog(0),
    m_progressShowTimer(this),
    m_refCounted(false)
{
    std::cerr << "RemoteFile::RemoteFile(" << fileOrUrl.toStdString() << ")" << std::endl;

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

    init(showProgress);

    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 << "RemoteFile::RemoteFile: Failed to retrieve URL \""
                      << fileOrUrl.toStdString() 
                      << "\" as human-readable URL; "
                      << "trying again treating it as encoded URL"
                      << std::endl;
            m_url.setEncodedUrl(fileOrUrl.toAscii());
            init(showProgress);
        }
    }
}

RemoteFile::RemoteFile(QUrl url, bool showProgress) :
    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_progressDialog(0),
    m_progressShowTimer(this),
    m_refCounted(false)
{
    std::cerr << "RemoteFile::RemoteFile(" << url.toString().toStdString() << ") [as url]" << std::endl;

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

    init(showProgress);
}

RemoteFile::RemoteFile(const RemoteFile &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_progressDialog(0),
    m_progressShowTimer(0),
    m_refCounted(false)
{
    std::cerr << "RemoteFile::RemoteFile(" << m_url.toString().toStdString() << ") [copy ctor]" << std::endl;

    if (!canHandleScheme(m_url)) {
        std::cerr << "RemoteFile::RemoteFile: 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);
        std::cerr << "RemoteFile::RemoteFile(copy ctor): ref count is "
                  << m_refCountMap[m_url] << std::endl;
        if (m_refCountMap[m_url] > 0) {
            m_refCountMap[m_url]++;
            std::cerr << "raised it to " << m_refCountMap[m_url] << std::endl;
            m_localFilename = m_remoteLocalMap[m_url];
            m_refCounted = true;
        } else {
            m_ok = false;
            m_lastStatus = 404;
        }
    }

    m_done = true;
}

RemoteFile::~RemoteFile()
{
    std::cerr << "RemoteFile(" << m_url.toString().toStdString() << ")::~RemoteFile" << std::endl;

    cleanup();

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

void
RemoteFile::init(bool showProgress)
{
    if (!isRemote()) {
        m_localFilename = m_url.toLocalFile();
        m_ok = true;
        if (!QFileInfo(m_localFilename).exists()) {
            m_lastStatus = 404;
        } else {
            m_lastStatus = 200;
        }
        m_done = true;
        return;
    }

    if (createCacheFile()) {
        std::cerr << "RemoteFile::init: Already have this one" << std::endl;
        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();

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

    if (scheme == "http") {
        initHttp();
    } 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]++;
            std::cerr << "RemoteFile::init: Another RemoteFile has got there first, abandoning our download and using theirs" << std::endl;
            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;

        if (showProgress) {
            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);
        }
    }
}

void
RemoteFile::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);

    std::cerr << "RemoteFile: path is \""
              << path.toStdString() << "\"" << std::endl;
        
    m_http->get(path, m_localFile);
}

void
RemoteFile::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
RemoteFile::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_localFile; // does not actually delete the file
    m_localFile = 0;
}

bool
RemoteFile::isRemote(QString fileOrUrl)
{
    QString scheme = QUrl(fileOrUrl).scheme().toLower();
    return (scheme == "http" || scheme == "ftp");
}

bool
RemoteFile::canHandleScheme(QUrl url)
{
    QString scheme = url.scheme().toLower();
    return (scheme == "http" || scheme == "ftp" ||
            scheme == "file" || scheme == "");
}

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

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

void
RemoteFile::waitForData()
{
    while (m_ok && !m_done) {
        QApplication::processEvents();
    }
}

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

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

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

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

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

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

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

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

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

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

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

void
RemoteFile::ftpCommandFinished(int id, bool error)
{
    std::cerr << "RemoteFile::ftpCommandFinished(" << id << ", " << error << ")" << std::endl;

    if (!m_ftp) return;

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

    if (!error) {
        std::cerr << "RemoteFile::ftpCommandFinished: success for command "
                  << command << std::endl;
        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
RemoteFile::dataTransferProgress(qint64 done, qint64 total)
{
    if (!m_progressDialog) return;

    int percent = int((double(done) / double(total)) * 100.0 - 0.1);
    emit progress(percent);

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

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

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

void
RemoteFile::done(bool error)
{
    std::cerr << "RemoteFile::done(" << error << ")" << std::endl;

    if (m_done) return;

    emit progress(100);

    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) {
        std::cerr << "RemoteFile::done: error is " << error << ", deleting cache file" << std::endl;
        deleteCacheFile();
    }

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

void
RemoteFile::deleteCacheFile()
{
    std::cerr << "RemoteFile::deleteCacheFile(\"" << m_localFilename.toStdString() << "\")" << std::endl;

    cleanup();

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

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

    if (m_refCounted) {

        QMutexLocker locker(&m_mapMutex);
        m_refCounted = false;

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

    m_fileCreationMutex.lock();

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

    m_fileCreationMutex.unlock();

    m_done = true;
}

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

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

        std::cerr << "RemoteFile::createCacheFile: refcount is " << m_refCountMap[m_url] << std::endl;

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

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

    std::cerr << "RemoteFile::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;

    QMutexLocker fcLocker(&m_fileCreationMutex);

    ++m_count;

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

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


        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)) {

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

            return "";
        }
    }

    std::cerr << "RemoteFile::createCacheFile: url "
              << m_url.toString().toStdString() << " -> local filename "
              << filepath.toStdString() << std::endl;
    
    m_localFilename = filepath;

    return false;
}