void TransferSender::writeItemData()
{
// Read the next chunk of data from the file - no more than either the size
// of the buffer or the amount of data remaining in the file
QByteArray buffer;
buffer.resize(mBufferSize);
qint64 bytesRead = mFile.read(buffer.data(), qMin(mFileBytesRemaining, static_cast<qint64>(mBufferSize)));
// Ensure that a valid number of bytes were read
if(bytesRead < 0 && mFileBytesRemaining) {
writeErrorPacket(tr("Unable to read from %1").arg(mFile.fileName()));
return;
}
// Write a packet containing the data that was just read
writeBinaryPacket(buffer.left(bytesRead));
// Update the number of bytes remaining in the file and the total transferred
mFileBytesRemaining -= bytesRead;
mTransferBytes += bytesRead;
// Provide a progress update
updateProgress();
// If there are no bytes remaining in the file close it and move on
if(!mFileBytesRemaining) {
mFile.close();
nextItem();
}
}
void Transfer::processPacket()
{
// Grab the data from the front of the buffer
const char type = mBuffer.at(0);
QByteArray data = mBuffer.mid(1, mBufferSize - 1);
mBuffer.remove(0, mBufferSize);
mBufferSize = 0;
// Process the data based on the type
switch (static_cast<PacketType>(type)) {
case PacketType::Success:
{
finish(TransferModel::Succeeded);
break;
}
case PacketType::Error:
{
// An error occurred - grab the error message
mError = QString::fromUtf8(data);
emit dataChanged({TransferModel::ErrorRole});
finish(TransferModel::Failed);
break;
}
case PacketType::Json:
{
// Verify the JSON is valid and pass it along
QJsonDocument document = QJsonDocument::fromJson(data);
if (document.isObject()) {
processJsonPacket(document.object());
} else {
writeErrorPacket(tr("Unable to read JSON packet"));
}
break;
}
case PacketType::Binary:
{
// Pass the packet along unmodified
processBinaryPacket(data);
break;
}
default:
// Any other type of packet is an error
writeErrorPacket(tr("Unrecognized packet received"));
}
}
void Transfer::cancel()
{
// Ensure that the transfer is actually in progress before trying to cancel it
if (mState == TransferModel::Failed || mState == TransferModel::Succeeded) {
qWarning("Cannot cancel a transfer that has completed");
return;
}
// Canceling a request is considered an "error" and is treated the same way
// Only attempt to report the error if the transfer isn't already finished
if (mProtocolState != ProtocolState::Finished) {
writeErrorPacket(tr("Transfer was canceled"));
}
}
void Transfer::onReadyRead()
{
// Add all of the new data to the buffer
mBuffer.append(mSocket->readAll());
// Process as many packets as can be read from the buffer
forever {
// If the transfer is finished, ignore any packets being received
if (mProtocolState == ProtocolState::Finished) {
break;
}
// If the size of the packet is not yet known attempt to read it
if (!mBufferSize) {
// See if there is enough data in the buffer to read the size
if (static_cast<size_t>(mBuffer.size()) >= sizeof(mBufferSize)) {
// memcpy must be used in order to avoid alignment issues
// Also, the integer uses little endian byte order
// so convert it to the host format if necessary
memcpy(&mBufferSize, mBuffer.constData(), sizeof(mBufferSize));
mBufferSize = qFromLittleEndian(mBufferSize);
mBuffer.remove(0, sizeof(mBufferSize));
// A packet size of zero is an error
if (!mBufferSize) {
writeErrorPacket(tr("Empty packet received"));
break;
}
} else {
break;
}
}
// If the buffer contains enough data to read the packet, then do so
if (mBuffer.size() >= mBufferSize) {
processPacket();
} else {
break;
}
}
}
void TransferSender::writeItemHeader()
{
// Build the header describing the item
QJsonObject header = QJsonObject::fromVariantMap({
{ "name", mCurrentItem->relativeFilename() },
{ "directory", mCurrentItem->isDir() },
{ "created", QString::number(mCurrentItem->created()) },
{ "last_modified", QString::number(mCurrentItem->lastModified()) },
{ "last_read", QString::number(mCurrentItem->lastRead()) }
});
if(mCurrentItem->isDir()) {
// If the item is a directory, write the
// header and move to the next item
writeJsonPacket(header);
nextItem();
} else {
// Set the filename and attempt to open the file
mFile.setFileName(mCurrentItem->absoluteFilename());
if(!mFile.open(QIODevice::ReadOnly)) {
writeErrorPacket(tr("Unable to open %1").arg(mCurrentItem->absoluteFilename()));
return;
}
// Obtain the file size, add it to the header, and send it
mFileBytesRemaining = mFile.size();
header.insert("size", QString::number(mFileBytesRemaining));
writeJsonPacket(header);
// If the file is empty, there's no need to send its contents
if(!mFileBytesRemaining) {
mFile.close();
nextItem();
}
}
}
void TransferSender::processBinaryPacket(const QByteArray &)
{
// Binary packets should never be received by the sender
writeErrorPacket(tr("Unexpected binary packet received"));
}
void TransferSender::processJsonPacket(const QJsonObject &)
{
// JSON packets should never be received by the sender
writeErrorPacket(tr("Unexpected JSON packet received"));
}
