Filezoo day 32: drag and drop handling

Added a handler for dealing with data dropped onto the Filezoo window. It copies or moves the source uri list (Konqueror, Nautilus, Firefox and others pass the DnD'd files as \r\n-separated strings of URIs) over to the drag target directory using Gnome-VFS. So now I can drag an image from Firefox onto a Filezoo directory and it'll be copied there.

The implementation was a wee bit challenging, since there was very little documentation for doing DragDrop event handling and perhaps even less for the Gnome.Vfs namespace. Here's what I used:

Handling data dropped on the widget, this is from the widget constructor:

  TargetEntry[] target_table = new TargetEntry [] {
    new TargetEntry ("text/uri-list", 0, 0),
    new TargetEntry ("text/plain", 0, 1),
    new TargetEntry ("STRING", 0, 1)
  };

  DragDataReceived += delegate (object sender, DragDataReceivedArgs e) {
    string type = e.SelectionData.Type.Name;
    Console.WriteLine(type);
    Gdk.DragAction action = e.Context.SuggestedAction;
    if (type == "text/uri-list" || (type == "text/plain" && IsURI(e.SelectionData.Text))) {
      string data = new System.Text.ASCIIEncoding().GetString(e.SelectionData.Data);
      string[] uris = data.Split(new char[] {'\r','\n','\0'},
                        StringSplitOptions.RemoveEmptyEntries);
      string msg = action.ToString() + " " + String.join(", ", uris);
    } else {
      Console.WriteLine("Got {0}", e.SelectionData.Text);
    }
  );

  Gtk.Drag.DestSet (this, DestDefaults.All, target_table,
      Gdk.DragAction.Move
    | Gdk.DragAction.Copy
    | Gdk.DragAction.Ask
  );

Using Gnome-VFS XferUriList to do a copy or move:

  public static void XferURIs
  (Gnome.Vfs.Uri[] sources, Gnome.Vfs.Uri[] targets, bool removeSources)
  {
    XferURIs (sources, targets, removeSources, ConsoleXferProgressCallback);
  }

  public static void XferURIs
  (Gnome.Vfs.Uri[] sources, Gnome.Vfs.Uri[] targets, bool removeSources, 
   Gnome.Vfs.XferProgressCallback callback)
  {
    Gnome.Vfs.Vfs.Initialize ();
    Gnome.Vfs.XferOptions mode = Gnome.Vfs.XferOptions.Recursive;
    if (removeSources) mode = mode | Gnome.Vfs.XferOptions.Removesource;
    Gnome.Vfs.Xfer.XferUriList (
      sources, targets, mode,
      Gnome.Vfs.XferErrorMode.Query,
      Gnome.Vfs.XferOverwriteMode.Replace,
      callback
    );
  }

  public static int ConsoleXferProgressCallback (Gnome.Vfs.XferProgressInfo info)
  {
    switch (info.Status) {
      case Gnome.Vfs.XferProgressStatus.Vfserror:
        Console.WriteLine("{0}: {1} in {2} -> {3}", 
          info.Status, info.VfsStatus, info.SourceName, info.TargetName);
        return (int)Gnome.Vfs.XferErrorAction.Abort;
      case Gnome.Vfs.XferProgressStatus.Overwrite:
        Console.WriteLine("{0}: {1} in {2} -> {3}", 
          info.Status, info.VfsStatus, info.SourceName, info.TargetName);
        return (int)Gnome.Vfs.XferOverwriteAction.Abort;
      default:
        Console.WriteLine("{0} / {1} {2} -> {3}", 
          info.BytesCopied, info.BytesTotal, info.SourceName, info.TargetName);
        return 1;
    }
  }

(Now I need a pimpin' progress indicator... maybe an arc to the dir with "incoming $STUFF -." or something with ambient notifications. Maybe just pop up a plain jane Gtk progress dialog :P)

Next features on this path would be dragging things around, navigating while dragging (think Finder's space-to-descend on steroids), and handling cut-copy-paste.