/****************************************************************************

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** This file is part of the QtNetwork module of the Qt Toolkit.

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** this package.

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** General Public License version 2.1 as published by the Free Software

** Foundation and appearing in the file LICENSE.LGPL included in the

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****************************************************************************/

#include "qnetworkaccessfilebackend_p.h"

#include "qfileinfo.h"

#include "qurlinfo.h"

#include "qdir.h"

#include "private/qnoncontiguousbytedevice_p.h"

#include <QtCore/QCoreApplication>

QT_BEGIN_NAMESPACE

QNetworkAccessBackend *

QNetworkAccessFileBackendFactory::create(QNetworkAccessManager::Operation op,

                                         const QNetworkRequest &request) const

{

    // is it an operation we know of?

    switch (op) {

    case QNetworkAccessManager::GetOperation:

    case QNetworkAccessManager::PutOperation:

        break;

    default:

        // no, we can't handle this operation

        return 0;

    }

    QUrl url = request.url();

    if (url.scheme() == QLatin1String("qrc") || !url.toLocalFile().isEmpty())

        return new QNetworkAccessFileBackend;

    else if (!url.isEmpty() && url.authority().isEmpty()) {

        // check if QFile could, in theory, open this URL

        QFileInfo fi(url.toString(QUrl::RemoveAuthority | QUrl::RemoveFragment | QUrl::RemoveQuery));

        if (fi.exists() || (op == QNetworkAccessManager::PutOperation && fi.dir().exists()))

            return new QNetworkAccessFileBackend;

    }

    return 0;

}

QNetworkAccessFileBackend::QNetworkAccessFileBackend()

    : uploadByteDevice(0), totalBytes(0), hasUploadFinished(false)

{

}

QNetworkAccessFileBackend::~QNetworkAccessFileBackend()

{

}

void QNetworkAccessFileBackend::open()

{

    QUrl url = this->url();

    if (url.host() == QLatin1String("localhost"))

        url.setHost(QString());

#if !defined(Q_OS_WIN)

    // do not allow UNC paths on Unix

    if (!url.host().isEmpty()) {

        // we handle only local files

        error(QNetworkReply::ProtocolInvalidOperationError,

              QCoreApplication::translate("QNetworkAccessFileBackend", "Request for opening non-local file %1").arg(url.toString()));

        finished();

        return;

    }

#endif // !defined(Q_OS_WIN)

    if (url.path().isEmpty())

        url.setPath(QLatin1String("/"));

    setUrl(url);

    QString fileName = url.toLocalFile();

    if (fileName.isEmpty()) {

        if (url.scheme() == QLatin1String("qrc"))

            fileName = QLatin1Char(':') + url.path();

        else

            fileName = url.toString(QUrl::RemoveAuthority | QUrl::RemoveFragment | QUrl::RemoveQuery);

    }

    file.setFileName(fileName);

    if (operation() == QNetworkAccessManager::GetOperation) {

        if (!loadFileInfo())

            return;

    }

    QIODevice::OpenMode mode;

    switch (operation()) {

    case QNetworkAccessManager::GetOperation:

        mode = QIODevice::ReadOnly;

        break;

    case QNetworkAccessManager::PutOperation:

        mode = QIODevice::WriteOnly | QIODevice::Truncate;

        uploadByteDevice = createUploadByteDevice();

        QObject::connect(uploadByteDevice, SIGNAL(readyRead()), this, SLOT(uploadReadyReadSlot()));

        QMetaObject::invokeMethod(this, "uploadReadyReadSlot", Qt::QueuedConnection);

        break;

    default:

        Q_ASSERT_X(false, "QNetworkAccessFileBackend::open",

                   "Got a request operation I cannot handle!!");

        return;

    }

    mode |= QIODevice::Unbuffered;

    bool opened = file.open(mode);

    // could we open the file?

    if (!opened) {

        QString msg = QCoreApplication::translate("QNetworkAccessFileBackend", "Error opening %1: %2")

                                                .arg(this->url().toString(), file.errorString());

        // why couldn't we open the file?

        // if we're opening for reading, either it doesn't exist, or it's access denied

        // if we're opening for writing, not existing means it's access denied too

        if (file.exists() || operation() == QNetworkAccessManager::PutOperation)

            error(QNetworkReply::ContentAccessDenied, msg);

        else

            error(QNetworkReply::ContentNotFoundError, msg);

        finished();

    }

}

void QNetworkAccessFileBackend::uploadReadyReadSlot()

{

    if (hasUploadFinished)

        return;

    forever {

        qint64 haveRead;

        const char *readPointer = uploadByteDevice->readPointer(-1, haveRead);

        if (haveRead == -1) {

            // EOF

            hasUploadFinished = true;

            file.flush();

            file.close();

            finished();

            break;

        } else if (haveRead == 0 || readPointer == 0) {

            // nothing to read right now, we will be called again later

            break;

        } else {

            qint64 haveWritten;

            haveWritten = file.write(readPointer, haveRead);

            if (haveWritten < 0) {

                // write error!

                QString msg = QCoreApplication::translate("QNetworkAccessFileBackend", "Write error writing to %1: %2")

                              .arg(url().toString(), file.errorString());

                error(QNetworkReply::ProtocolFailure, msg);

                finished();

                return;

            } else {

                uploadByteDevice->advanceReadPointer(haveWritten);

            }

            file.flush();

        }

    }

}

void QNetworkAccessFileBackend::closeDownstreamChannel()

{

    if (operation() == QNetworkAccessManager::GetOperation) {

        file.close();

    }

}

bool QNetworkAccessFileBackend::waitForDownstreamReadyRead(int)

{

    Q_ASSERT(operation() == QNetworkAccessManager::GetOperation);

    return readMoreFromFile();

}

void QNetworkAccessFileBackend::downstreamReadyWrite()

{

    Q_ASSERT_X(operation() == QNetworkAccessManager::GetOperation, "QNetworkAccessFileBackend",

               "We're being told to download data but operation isn't GET!");

    readMoreFromFile();

}

bool QNetworkAccessFileBackend::loadFileInfo()

{

    QFileInfo fi(file);

    setHeader(QNetworkRequest::LastModifiedHeader, fi.lastModified());

    setHeader(QNetworkRequest::ContentLengthHeader, fi.size());

    // signal we're open

    metaDataChanged();

    if (fi.isDir()) {

        error(QNetworkReply::ContentOperationNotPermittedError,

              QCoreApplication::translate("QNetworkAccessFileBackend", "Cannot open %1: Path is a directory").arg(url().toString()));

        finished();

        return false;

    }

    return true;

}

bool QNetworkAccessFileBackend::readMoreFromFile()

{

    qint64 wantToRead;

    while ((wantToRead = nextDownstreamBlockSize()) > 0) {

        // ### FIXME!!

        // Obtain a pointer from the ringbuffer!

        // Avoid extra copy

        QByteArray data;

        data.reserve(wantToRead);

        qint64 actuallyRead = file.read(data.data(), wantToRead);

        if (actuallyRead <= 0) {

            // EOF or error

            if (file.error() != QFile::NoError) {

                QString msg = QCoreApplication::translate("QNetworkAccessFileBackend", "Read error reading from %1: %2")

                              .arg(url().toString(), file.errorString());

                error(QNetworkReply::ProtocolFailure, msg);

                finished();

                return false;

            }

            finished();

            return true;

        }

        data.resize(actuallyRead);

        totalBytes += actuallyRead;

        QByteDataBuffer list;

        list.append(data);

        data.clear(); // important because of implicit sharing!

        writeDownstreamData(list);

    }

    return true;

}

QT_END_NAMESPACE