* lisp/dnd.el (dnd-protocol-alist): Redefine file name handlers
to match solely the local or remote URIs they understand.
(dnd-handle-multiple-urls): Prevent calling the same handler
multiple times for a single URI.
* lisp/gnus/mml.el (mml-dnd-protocol-alist): Apply an anologous
adjustment here. Delete now redundant redefinition of
dnd-open-file.
(mml-dnd-attach-file): Inquire whether to apply the default
disposition and such only once even if more than one file is
dropped.
* test/lisp/dnd-tests.el (dnd-tests-receive-multiple-urls)
(dnd-tests-default-file-name-handlers): New tests.
* doc/lispref/frames.texi (Drag and Drop): Illustrate the effect
of the dnd-multiple-handler property and how convergent handlers
are reconciled.
* etc/NEWS (Lisp Changes in Emacs 30.1): Announce this change.
* lisp/dnd.el (dnd-protocol-alist): Bring doc string up to date.
(dnd-handle-one-url): Obsolete this function.
(dnd-handle-multiple-urls): New function.
* lisp/pgtk-dnd.el (pgtk-dnd-handle-uri-list)
(pgtk-dnd-handle-file-name):
* lisp/term/android-win.el (android-handle-dnd-event):
* lisp/term/haiku-win.el (haiku-drag-and-drop):
* lisp/term/ns-win.el (ns-drag-n-drop):
* lisp/term/w32-win.el (w32-handle-dropped-file):
* lisp/x-dnd.el (x-dnd-handle-uri-list, x-dnd-handle-file-name):
Reimplement in terms of `dnd-handle-multiple-uris'.
* lisp/term/pgtk-win.el (pgtk-drag-n-drop)
(pgtk-drag-n-drop-other-frame, pgtk-drag-n-drop-as-text): Efface
detritus that remained after the removal of the old PGTK drag
and drop implementation.
* test/lisp/dnd-tests.el (ert-x, dnd-tests-list-1)
(dnd-tests-list-2, dnd-tests-list-3, dnd-tests-list-4)
(dnd-tests-local-file-function, dnd-tests-remote-file-function)
(dnd-tests-http-scheme-function, dnd-tests-browse-url-handler)
(dnd-tests-receive-multiple-urls): New tests.
* lisp/x-dnd.el (x-dnd-handle-old-kde, x-dnd-handle-offix)
(x-dnd-handle-motif): Select window before handling drop, like
on Xdnd.
(x-dnd-convert-to-offix, x-dnd-do-offix-drop)
(x-dnd-handle-unsupported-drop): Accept local selection data and
use that instead.
* src/keyboard.c (kbd_buffer_get_event): Call unsupported drop
function with local selection data as 8th arg.
* src/xselect.c (x_get_local_selection): Accept new arg
`local_value'. All callers changed.
(Fx_get_local_selection): New function.
(syms_of_xselect): Update defsubrs.
* src/xterm.c (x_dnd_lose_ownership): New function.
(x_dnd_begin_drag_and_drop): Unless new variable is true, disown
XdndSelection after returning. This supposedly makes
drag-and-drop from guest to host work in VirtualBox without
causing pointer motion to become choppy afterwards.
(syms_of_xterm): New variable `x_dnd_preserve_selection_data'
and update doc string of `x-dnd-unsupported-drop-function'.
* test/lisp/dnd-tests.el (dnd-tests-begin-text-drag)
(dnd-tests-begin-file-drag, dnd-tests-begin-drag-files): Set new
variable to nil during tests.
* lisp/select.el (xselect-convert-to-dt-netfile): Encode file
name before computing its tooltalk name, since the indices work
on bytes.
* test/lisp/dnd-tests.el (dnd-tests-begin-file-drag): Add test.
* src/xselect.c (x_get_local_selection): Respect new variable.
(syms_of_xselect): New variable
`x-treat-local-requests-remotely'.
* test/lisp/dnd-tests.el (x-begin-drag, gui-set-selection):
Don't redefine these functions under X.
(dnd-tests-verify-selection-data): Use
`x-get-selection-internal' under X.
(dnd-tests-extract-selection-data): New function.
(dnd-tests-begin-text-drag): Update accordingly.
(dnd-tests-begin-file-drag, dnd-tests-begin-drag-files):
Temporarily skip these tests under X.
* test/lisp/dnd-tests.el (dnd-tests-selection-table): New
defvar.
(gui-set-selection): Actually implement in a way that validates
the local value and stores it for future use.
(dnd-tests-verify-selection-data): New function.
(dnd-tests-begin-text-drag): Add tests for the contents of
various selections.
