Daily Archives: 20 June, 2005

Phillip: your idea about direct client to client clipboard transfers is doable with the current X11 clipboard model:

1. Clipboard owner advertises that it can convert selection to some special target type such as “client-to-client-transfer” or similar.
2. If the pasting client supports client to client transfer, it can check the list of supported targets for the “client-to-client-transfer” target type and request conversion to that target.
3. The clipboard owner returns a string containing details of how to request the data (e.g. hostname/port, or some other scheme that only works for the local host).
4. Pasting application contacts the owner out of band and receives the data.

Yes, this requires modifications to applications in order to work correctly, but so would switching to a new clipboard architecture.

With respect to your no-transfer cut/paste of a movie example, that’s more of a component architecture problem than a clipboard issue. In the context of Bonobo, it can be done provided that the clipboard owner can provide the data as a Bonobo Embeddable, and the pasting application can embed Bonobo Embeddables in its documents:

1. Clipboard owner advertises that it can convert the selection to the target “BONOBO_EMBEDDABLE” (or some other agreed upon targer name).
2. Pasting application requests that the selection be converted to “BONOBO_EMBEDDABLE”, and receives an IOR for the component. Pasting application owns a reference on the component due to the clipboard transfer.
3. Pasting application queryInterface()‘s the component to the Bonobo::ControlFactory interface, and calls the createControl() method to create a control to embed in the document.
4. When it comes time to save the data, the component can be converted to one of the Bonobo::Persist interfaces, and written out.

Of course, there are reasons why people don’t do this (apart from not liking Bonobo), including:

• With the classic X selection model, you don’t need to special case local or remote transfer cases.
• Works in cases where the two applications can only communicate via the X connection (e.g. in the presence of transparent X proxies such as ssh).
• It delegates all the permissions/authentication issues to the X server.