[Spice-devel] [PATCH win-vdagent] Support file transfer for existing files

[Pavel Grunt]

On Thu, 2017-04-27 at 10:25 -0500, Jonathon Jongsma wrote:
> On Wed, 2017-04-26 at 17:50 -0400, Frediano Ziglio wrote:
> > > 
> > > Previously, if the user attempted to transfer a file that had
> > > the
> > > same
> > > name as a file that already exists on the guest, we would just
> > > fail
> > > the
> > > transfer. This patch tries to match the behavior of the linux
> > > vdagent
> > > where we try to append an integer onto the name of the new file
> > > to
> > > make
> > > it unique. For example, if you tried to transfer 'file.doc' to
> > > the
> > > guest
> > > and that file already existed, it would try to create 'file.doc
> > > (1)'
> > > instead. If that also failed, it would attempt 'file.doc (2)',
> > > etc,
> > > up
> > > to 63.
> > > 
> > 
> > Not really user friendly, Windows is really extension based.
> > Would be better to be 'file (1).doc' for 'file.doc'.
> > Yes, not easy to implement as adding " (xx)".
> 
> True, I just tried to copy the behavior of the linux vdagent (as
> suggested in the bug), but perhaps we should do it a bit differently
> for windows. Or maybe we should change both the linux and vdagent to
> work this way...

Probably. I checked Nautilus and Thunar (file managers in Gnome and
Xfce) behavior when copying a same file in the same folder and they
are adding (xxx) before the extension suffix.

Pavel

> 
> > 
> > > Resolves: rhbz#1410181
> > > ---
> > >  vdagent/file_xfer.cpp | 38 ++++++++++++++++++++++++++++++++--
> > > ----
> > >  1 file changed, 32 insertions(+), 6 deletions(-)
> > > 
> > > diff --git a/vdagent/file_xfer.cpp b/vdagent/file_xfer.cpp
> > > index f763ed3..14e2098 100644
> > > --- a/vdagent/file_xfer.cpp
> > > +++ b/vdagent/file_xfer.cpp
> > > @@ -61,6 +61,7 @@ void
> > > FileXfer::handle_start(VDAgentFileXferStartMessage*
> > > start,
> > >      HANDLE handle;
> > >      AsUser as_user;
> > >      int wlen;
> > > +    int attempt = 0;
> > >  
> > >      status->id = start->id;
> > >      status->result = VD_AGENT_FILE_XFER_STATUS_ERROR;
> > > @@ -99,15 +100,40 @@ void
> > > FileXfer::handle_start(VDAgentFileXferStartMessage*
> > > start,
> > >  
> > >      file_path[wlen++] = TEXT('\\');
> > >      file_path[wlen] = TEXT('\0');
> > > -    if((wlen = MultiByteToWideChar(CP_UTF8, 0, file_name, -1,
> > > file_path +
> > > wlen, MAX_PATH - wlen)) == 0){
> > > -        vd_printf("failed converting file_name:%s to WideChar",
> > > file_name);
> > > -        return;
> > > +
> > > +    const int MAX_ATTEMPTS = 64; // matches behavior of linux
> > > vdagent
> > > +    const size_t POSTFIX_LEN = 6; // up to 2 digits in
> > > parentheses
> > > and final
> > > NULL: " (xx)"
> > > +    size_t name_len = strlen(file_name);
> > > +    for (attempt = 0; attempt < MAX_ATTEMPTS; attempt++) {
> > > +        char *pos = &file_name[name_len];
> > > +        if (attempt > 0) {
> > > +            if (name_len + POSTFIX_LEN > MAX_PATH) {
> > > +                vd_printf("failed creating %ls. Postfix makes
> > > name
> > > too long
> > > for the buffer.", file_path);
> > > +                return;
> > > +            }
> > > +            snprintf(pos, POSTFIX_LEN, " (%d)", attempt);
> > > +        }
> > > +        if((MultiByteToWideChar(CP_UTF8, 0, file_name, -1,
> > > file_path + wlen,
> > > MAX_PATH - wlen)) == 0){
> > > +            vd_printf("failed converting file_name:%s to
> > > WideChar",
> > > file_name);
> > > +            return;
> > > +        }
> > > +        handle = CreateFile(file_path, GENERIC_WRITE, 0, NULL,
> > > CREATE_NEW,
> > > 0, NULL);
> > > +        if (handle != INVALID_HANDLE_VALUE) {
> > > +            break;
> > > +        }
> > > +
> > > +        // If the file already exists, we can re-try with a new
> > > filename. If
> > > +        // it's a different error, there's not much we can do.
> > > +        if (GetLastError() != ERROR_FILE_EXISTS) {
> > 
> > I would include the old line:
> > 
> >    vd_printf("failed creating %ls %lu", file_path,
> > GetLastError());
> > 
> > > +            return;
> > > +        }
> > >      }
> > > -    handle = CreateFile(file_path, GENERIC_WRITE, 0, NULL,
> > > CREATE_NEW, 0,
> > > NULL);
> > > -    if (handle == INVALID_HANDLE_VALUE) {
> > > -        vd_printf("failed creating %ls %lu", file_path,
> > > GetLastError());
> > > +
> > > +    if (attempt == MAX_ATTEMPTS) {
> > > +        vd_printf("Failed creating %ls. More than 63 copies
> > > exist?",
> > > file_path);
> > >          return;
> > >      }
> > > +
> > >      task = new FileXferTask(handle, file_size, file_path);
> > >      _tasks[start->id] = task;
> > >      status->result = VD_AGENT_FILE_XFER_STATUS_CAN_SEND_DATA;
> > 
> > Frediano
> 
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