text: /****************************************************************************
  **
  ** Copyright (C) 2016 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the QtNetwork module of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:LGPL$
  ** Commercial License Usage
  ** Licensees holding valid commercial Qt licenses may use this file in
  ** accordance with the commercial license agreement provided with the
  ** Software or, alternatively, in accordance with the terms contained in
  ** a written agreement between you and The Qt Company. For licensing terms
  ** and conditions see https://www.qt.io/terms-conditions. For further
  ** information use the contact form at https://www.qt.io/contact-us.
  **
  ** GNU Lesser General Public License Usage
  ** Alternatively, this file may be used under the terms of the GNU Lesser
  ** General Public License version 3 as published by the Free Software
  ** Foundation and appearing in the file LICENSE.LGPL3 included in the
  ** packaging of this file. Please review the following information to
  ** ensure the GNU Lesser General Public License version 3 requirements
  ** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
  **
  ** GNU General Public License Usage
  ** Alternatively, this file may be used under the terms of the GNU
  ** General Public License version 2.0 or (at your option) the GNU General
  ** Public license version 3 or any later version approved by the KDE Free
  ** Qt Foundation. The licenses are as published by the Free Software
  ** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
  ** included in the packaging of this file. Please review the following
  ** information to ensure the GNU General Public License requirements will
  ** be met: https://www.gnu.org/licenses/gpl-2.0.html and
  ** https://www.gnu.org/licenses/gpl-3.0.html.
  **
  ** $QT_END_LICENSE$
  **
  ****************************************************************************/
  
  #include "qnetworkaccessfilebackend_p.h"
  #include "qfileinfo.h"
  #if QT_CONFIG(ftp)
  #include "qurlinfo_p.h"
  #endif
  #include "qdir.h"
  #include "private/qnoncontiguousbytedevice_p.h"
  
  #include <QtCore/QCoreApplication>
  #include <QtCore/QDateTime>
  
  QT_BEGIN_NAMESPACE
  
  QStringList QNetworkAccessFileBackendFactory::supportedSchemes() const
  {
      QStringList schemes;
      schemes << QStringLiteral("file")
              << QStringLiteral("qrc");
  #if defined(Q_OS_ANDROID)
      schemes << QStringLiteral("assets");
  #endif
      return schemes;
  }
  
  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().compare(QLatin1String("qrc"), Qt::CaseInsensitive) == 0
  #if defined(Q_OS_ANDROID)
              || url.scheme().compare(QLatin1String("assets"), Qt::CaseInsensitive) == 0
  #endif
              || url.isLocalFile()) {
          return new QNetworkAccessFileBackend;
      } else if (!url.scheme().isEmpty() && url.authority().isEmpty() && (url.scheme().length() > 1)) {
          // check if QFile could, in theory, open this URL via the file engines
          // it has to be in the format:
          //    prefix:path/to/file
          // or prefix:/path/to/file
          //
          // this construct here must match the one below in open()
          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 {
  #if defined(Q_OS_ANDROID)
              if (url.scheme() == QLatin1String("assets"))
                  fileName = QLatin1String("assets:") + url.path();
              else
  #endif
                  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();
      }
  }
  
  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
  