[Telepathy] tp-qt4 FileTransfer API proposal

[Andre Moreira Magalhaes]

Hi,

One more API sketch for review. This time we are going to implement 
FileTransfer
support on tp-qt4 and I would like to have some review comments on the API.

For those not familiar with FileTransfer please refer to
http://telepathy.freedesktop.org/spec.html#org.freedesktop.Telepathy.Channel.Type.FileTransfer

Aditional methods that will be added to Account:

class Account ...
{
     ...

    PendingChannelRequest *createFileTransfer(
            const QString &contactIdentifier,
            const QString &fileName,
            const QString &contentType,
            qulonglong size,
            FileHashType contentHashType = (FileHashType) -1,
            const QString &contentHash = QString(),
            const QString &description = QString(),
            QDateTime lastModificationTime = QDateTime(),
            QDateTime userActionTime = QDateTime::currentDateTime(),
            const QString &preferredHandler = QString());
    PendingChannelRequest *createFileTransfer(
            const ContactPtr &contact,
            const QString &fileName,
            const QString &contentType,
            qulonglong size,
            FileHashType contentHashType = (FileHashType) -1,
            const QString &contentHash = QString(),
            const QString &description = QString(),
            QDateTime lastModificationTime = QDateTime(),
            QDateTime userActionTime = QDateTime::currentDateTime(),
            const QString &preferredHandler = QString());
            
    ...
}

Additional methods added to FileTransferChannel

class FileTransferChannel ...
{
    ...
    
    QString fileName() const;
    QString contentType() const;
    qulonglong size() const;

    FileHashType contentHashType() const;
    QString contentHash() const;

    QString description() const;

    QDateTime lastModificationTime() const;

    qulonglong initialOffset() const;

    qulonglong transferredBytes() const;

    PendingOperation *profileFile(QIODevice *device);
    PendingIODevice *acceptFile(qulonglong offset);

Q_SIGNALS:
    void stateChanged(FileTransferState state, FileTransferStateReason 
reason);
    void transferredBytesChanged(qulonglong count);
    void initialOffsetDefined(qulonglong offset);

    ...
}

In order to provide a file one has to call 
FileTransferChannel::provideFile with
a QIODevice as param. The idea is that internally we will create a 
socket to be
used to transfer the file, but this is transparent to the user. 
QIODevice was
choosen because it abstracts I/O devices access (file, buffer, socket, ...).

To accept a file, FileTransferChannel::acceptFile should be called, 
which will return
a PendingIODevice, that will contain a QIODevice where the user can read 
from it,
when the method returns.

I am not sure if we should provide more "low-level" methods to provide 
file and
accept file that should take sockets as params, but I believe the above 
methods
should be enough.

Ideas, suggestions are welcome.

BR
Andrunko