Instead of letting the wayland bits maintain an always-software
cursor renderer, let the cursor renderer be managed by the backend,
and only hook to it (as we do for pointer cursor) in the wayland
bits.
ATM, make the cursor renderer still always-software, although
ideally we should allow moving the HW cursor management between
renderers.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1403>
Since we schedule frames for each stage view seperately now, surfaces receive
frame callbacks for each stage view they are visible on.
Only emit frame callbacks for the primary stage view.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1468>
For X11 grabs, the pattern matching mechanism would simply ignore
applications which have neither WM_CLASS nor WM_NAME set.
When dealing with an override redirect window however, it is not
uncommon that these window have neither value set as these window are
supposed to be ignored by the window manager.
When the WM_CLASS or the WM_NAME is not set by the client, assume the
value is empty so the pattern matching can allow for these.
https://gitlab.gnome.org/GNOME/mutter/-/issues/1249
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1254>
Commit 8bdd2aa7 would offset the window position by the difference
between the configured window size and the committed size from the
client to prevent the window from drifting while resizing.
This, however, did not take into account the actual geometry scale, so
when using any scale greater than 1, the window would rapidly drift away
due to that offset.
In order to solve this, we need to make sure we store away the pending
window configuration in the stage coordinate space, in order to not
loose precision. When we then calculate the offset given the result from
the client, it'll use the right scalars, while before, one scalar was in
surface coordinates, while the other in stage coordinates.
https://gitlab.gnome.org/GNOME/mutter/-/issues/1490
The semantics for libinput events are not as expected here. Besides
it's pointless, as those should arrive per-slot in a burst, and we
cancel on the first event.
We can simply use the Clutter event for this.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1486
We want to coalesce multiple touch events into the same wl_touch.frame
event. Instead of poking internals to peek the touch events (and their
slots) coming at us before we handle them, simplify things by queueing
the event at a slightly lower priority than events, so we are ensured
to handle all pending input events before sending the event.
If there's no pending events, we can just send the frame event. As it
doesn't make sense to hold any longer.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1486
Implements the "prior window window geometry dimensions" as described in
the documentation of 'xdg_toplevel' request 'unset_maximized':
"If available and applicable, the compositor will include the window
geometry dimensions the window had prior to being maximized in the
configure event."
and 'unset_fullscreen':
"The compositor may include the previous window geometry dimensions in
the configure event, if applicable."
Fixes https://gitlab.gnome.org/GNOME/mutter/issues/792.
If this call is available, we can turn libX11 IO errors (fatal by definition)
into something we can recover from. Try to dispose all X11 resources and close
the display instead, so the compositor can survive the event.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1447
If the MetaX11Display abruptly closed when X11 windows were present,
we would still try to deal with them while freezing/thawing for the
"fade out" animation.
At the bottom of that, the X server may be gone, just try to cope
with it.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1447
The spec states:
```
A sub-surface becomes mapped, when a non-NULL wl_buffer is applied
and the parent surface is mapped. The order of which one happens
first is irrelevant. A sub-surface is hidden if the parent becomes hidden,
or if a NULL wl_buffer is applied. These rules apply recursively
through the tree of surfaces.
```
In the past we relied on Clutter actor behaviour to realize the recursive
part - which then broke in
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/664
when we changed the actor hierachy in regards to subsurfaces.
Explicitly encode the desired behaviour in `MetaWaylandSubsurface`, fixing
the issue and making it future proof.
Closes https://gitlab.gnome.org/GNOME/mutter/-/issues/1384
Mutter sends a proximity-in event before the required tablet tool
resource is properly allocated on the client. This is violating the
Wayland protocol. Because libwayland ignores events for objects it
doesn't know yet, this is not noticeable in most applications. However,
if https://gitlab.freedesktop.org/wayland/wayland/-/issues/176 gets
fixed, these applications would likely crash immediately. Therefore this
PR removes the responsible code which, again, shouldn't have any effect
on client applications as they ignore this event anyway.
Relevant part of the spec:
This event can be received when the tool has moved from one surface to
another, or when the tool has come back into proximity above the
surface.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1427
When we resize a window we send it configure requests with size
suggestion. Some clients, e.g. gnome-terminal will limit its size to a
discrete set given the font size resulting in the size often not being
respected completely, but used as a hint to find a size as large as
possible but not larger than the configured size.
When doing an interactive resize dragging the right or top side of a
window, this caused issues with the configured window size not matching
the one used by the client, as the configured position wouldn't be
correct for the actual size. Fix this by offsetting the position given
the size mismatch offset, making the position again in sync with the
size.
Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/1447https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1477
A Meta.WaylandClient() object has a GSubprocessLauncher object
passed externally. Currently this object is kept while the
WaylandClient object exists, but is is only needed until the call
to spawn is made.
This patch frees that GSubprocessLauncher just after that call,
thus freeing those resources.
Fix https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1462
Wayland clients using buffers without alpha channel are not expected to
set an opaque region. However, we rely on the opaque region for the fast
painting path in `MetaShapedTexture`.
Thus, make sure to always set an opaque region internally in those cases.
For X11 clients, wo do so already.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1463
The Meta.WaylandClient constructor receives a GSubprocessLauncher
as a parameter, and stores it internally. Unfortunately, its
refcount value isn't increased, which results in the object being
released twice.
This patch fixes this bug.
Fix https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1454
We only did this if we weren't currently doing an interactive resize,
but since the finish_move_resize() is not the actual interactive resize
but the acknowledgment of the configure event that was emitted as a
result, we shouldn't limit ourself to the same flags used during resize.
This fixes temporarly "stuck" position of attached modal dialogs while
they are being resized.
Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/1163https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1446
Just because X11/XI uses a particular terminology doesn't mean we
have to use the same terms in our own API. The replacement terms
are in line with gtk@1c856a208, which seems a better precedent
for consistency.
Follow-up to commit 17417a82a5.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1425
This is no longer directly related to DBus messages, but our own event
queue. Change the wording and use CLUTTER_PRIORITY_EVENTS to make it
bolder, even though it's the same than G_PRIORITY_DEFAULT.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1286
We set an idle to coalesce multiple IM events together, as the protocol
requires us to send them in one frame, and unfortunately there is no
idea about whether more IM events are upcoming.
One good hint though are key events generated from the IM, we want to
apply all IM changes before the key event is processed, so make it sure
that the .done event is flushed before the key event is handled.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1286
The clutter_input_focus_filter_key_event() function has been made
a more generic filter_event(). Besides its old role about letting
key events go through the IM, it will also process the IM events
that are possibly injected as a result.
Users have been updated to these changes.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1286
There's no need to update the outputs recursively in case the actor gets
mapped or unmapped. That's because mapping happens recursively itself,
so if a window with multiple subsurfaces is shown, all subsurfaces will
receive a "notify::mapped" signal.
Since this was the only remaining user of
meta_wayland_surface_update_outputs_recursively(), we can now remove
that function.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1358
Since we now listen to the "stage-views-on-changed" signal (which
"catches" all the changes we want) on MetaWaylandActorSurfaces for
updating the wl_outputs the surface is on, we no longer need to call
meta_wayland_surface_update_outputs_recursively() on all geometry
changes, so remove that signal handler.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1358
ClutterActors new "stage-views-changed" signal fits pretty well for the
updating of wl_outputs a MetaWaylandActorSurface is on: With that signal
we get notified if the surface moved to a different CRTC, of which every
output has at least one.
So start listening to that signal, which fixes a bug where the wl_output
of a surface changes, but its allocation remains the same (which means
no signals triggering an update of the outputs will be emitted) and no
enter/leave events for the new wl_outputs are sent to the client. This
can happen when a monitor is hotplugged but the new allocation is
exactly the same as the old one even though it's on a different monitor.
Since the "stage-views-on-changed" signal will also get emitted when a
parent actor of the surface is moved, this means we can now remove the
call to meta_wayland_surface_update_outputs_recursively() on window
position changes or the completion of window-effects.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1358
The X server, including Xwayland, can be compiled with different X11
extensions enabled at build time.
When an X11 extension is built in the X server, it's usually also
enabled at run time. Users can chose to disable those extensions at run
time using the X server command line option "-extension".
However, in the case of Xwayland, it is spawned automatically by the
Wayland compositor, and the command line options are not configurable
by users.
Add a new setting to disable a selected set of X extension in Xwayland
at startup, without needing to rebuild Xwayland.
Of course, if Xwayland is not built with a given extension support in
the first place (which is the default for the security extension for
example), that option has no effect.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1405
If we returned early in one of the checks but already assigned the
surface role, we'd later run into a double-free and crash. Just do
the checks at the beginning.
Also add a missing return statement that was left out in commit
88ff196fe3 and tighten the parent surface check.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1415
The spec allows `parent_resource` to be `NULL`, requiring the parent
surface to get specified by some other protocol. Send a protocol error
with some meaningful explanation instead of crashing.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1408
Clients can set minimum and maximum to identical values to indicate a
fixed-size window. A compositor can ignore these requests and thus a client
has to ensure these limits.
To support clients that do not ensure these size limits by themselves and
to skip unnecessary function calls, we will prevent resizing requests by
the client if a fixed-size has been requested.
https://gitlab.gnome.org/GNOME/mutter/-/issues/1331
Just as wl_shm, hook up the Wayland DMA-BUF protocol to the 64 bit half
point pixel formats too. This makes it possible for Wayland EGL clients
to use 64 bit pixel EGL configurations.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/804
Now that cogl understands them, hook wl_shm up so they can be used.
This also bumps the wayland-server version dependency to 1.17.90, which
corresponds to the master branch of wayland. The new formats will be
available in 1.18.0.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/804
Allowing code from inside mutter to create a child process and
delegate on it some of its tasks is something very useful. This can
be done easily with the g_subprocess and g_subprocess_launcher classes
already available in GLib and GObject.
Unfortunately, although the child process can be a graphical program,
currently it is not possible for the inner code to identify the
windows created by the child in a secure manner (this is: being able
to ensure that a malicious program won't be able to trick the inner
code into thinking it is a child process launched by it).
Under X11 this is not a problem because any program has full control
over their windows, but under Wayland it is a different story: a
program can't neither force their window to be kept at the top (like a
docker program does) or at the bottom (like a program for desktop icons
does), nor hide it from the list of windows. This means that it is not
possible for a "classic", non-priviledged program, to fulfill these
tasks, and it can be done only from code inside mutter (like a
gnome-shell extension).
This is a non desirable situation, because an extension runs in the
same main loop than the whole desktop itself, which means that a
complex extension can need to do too much work inside the main loop,
and freeze the whole desktop for too much time. Also, it is important
to note that javascript doesn't have access to fork(), or threads,
which means that, at most, all the parallel computing that can do is
those available in the _async calls in GLib/GObject.
Also, having to create an extension for any priviledged graphical
element is an stopper for a lot of programmers who already know
GTK+ but doesn't know Clutter.
This patch wants to offer a solution to this problem, by offering a
new class that allows to launch a trusted child process from inside
mutter, and make it to use an specific UNIX socket to communicate
with the compositor. It also allows to check whether an specific
MetaWindow was created by one of this trusted child processes or not.
This allows to create extensions that launch a child process, and
when that process creates a window, the extension can confirm in a
secure way that the window really belongs to that process
launched by it, so it can give to that window "superpowers" like
being kept at the bottom of the desktop, not being listed in the
list of windows or shown in the Activities panel... Also, in future
versions, it could easily implement protocol extensions that only
could be used by these trusted child processes.
Several examples of the usefulness of this are that, with it, it
is possible to write programs that implements:
- desktop icons
- a dock
- a top or bottom bar
...
all in a secure manner, avoiding insecure programs to do the same.
In fact, even if the same code is launched manually, it won't have
those privileges, only the specific process launched from inside
mutter.
Since this is only needed under Wayland, it won't work under X11.
Fixes https://gitlab.gnome.org/GNOME/mutter/issues/741
Replace the default master clock with multiple frame clocks, each
driving its own stage view. As each stage view represents one CRTC, this
means we draw each CRTC with its own designated frame clock,
disconnected from all the others.
For example this means we when using the native backend will never need
to wait for one monitor to vsync before painting another, so e.g. having
a 144 Hz monitor next to a 60 Hz monitor, things including both Wayland
and X11 applications and shell UI will be able to render at the
corresponding monitor refresh rate.
This also changes a warning about missed frames when sending
_NETWM_FRAME_TIMINGS messages to a debug log entry, as it's expected
that we'll start missing frames e.g. when a X11 window (via Xwayland) is
exclusively within a stage view that was not painted, while another one
was, still increasing the global frame clock.
Addititonally, this also requires the X11 window actor to schedule
timeouts for _NET_WM_FRAME_DRAWN/_NET_WM_FRAME_TIMINGS event emitting,
if the actor wasn't on any stage views, as now we'll only get the frame
callbacks on actors when they actually were painted, while in the past,
we'd invoke that vfunc when anything was painted.
Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/903
Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/3https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1285
Instead of going via MetaCompositor to know about when we updated
(confusingly named post-paint), use the new stage signal directly.
Note that this doesn't change the time frame callbacks are dispatched;
it's still not tied to actual painting even though it seemed so before
given the function names.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1285
Event delivery with grabbing popups stay essentially the same within
the grabbing client, we still must honor the implicit grab as long as
there is one.
This is however not the case, the popup_grab_focus() function ignores
the button state. The popup_grab_button() function will already indirectly
re-sync the focus surface after the last button is released, so checking
for button state in popup_grab_focus() is sufficient to make the implicit
grab honored with popup grabs involved.
Fixes: https://gitlab.gnome.org/GNOME/mutter/-/issues/1275https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1270
Make the clutter_input_device_get_actor() API public and remove
clutter_input_device_get_pointer_actor() in favour of the new function.
This allows also getting the "pointer" actor for a given touch sequence,
not only for real pointer input devices like mice.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1275
Move Wayland support (i.e. the MetaWaylandCompositor object) made to be
part of the backend. This is due to the fact that it is needed by the
backend initialization, e.g. the Wayland EGLDisplay server support.
The backend is changed to be more involved in Wayland and clutter
initialization, so that the parts needed for clutter initialization
happens before clutter itself initialization happens, and the rest
happens after. This simplifies the setup a bit, as clutter and Wayland
init now happens as part of the backend initialization.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1218
There's no reason to notify the surface that its geometry changed when
the visibility of the actor changes. This is only needed to update the
outputs of the surface, so do that directly instead.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1235
We started listening to notify::mapped with commit
5eb5f72434 in order to emit
wl_surface.leave events consistently when a surface gets hidden. This
caused a problem with the ClutterClones used in the overview, since
those temporarily map and unmap the windows for painting, spamming
wl_surface.leave and enter events to all surfaces.
We can easily fix that by also treating mapped clones as mapped, which
means the surface should also be on a wl_output when the overview is
shown.
Fixes https://gitlab.gnome.org/GNOME/mutter/-/issues/1141https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1235
We started listening to "notify::position" on surface actors with commit
08e4cb54. This commit was done to fix a regression from commit cf1edff9,
which forgot to handle some cases like the actual WindowActor and not
the SurfaceActor (which is a child of the WindowActor) moving (that was
fixed by listening to MetaWindows "position-changed" signal). Also that
commit introduced meta_wayland_surface_update_outputs_recursively(),
which updates the outputs of all (sub-)surfaces in case any position
changed and made sure subsurfaces also get their outputs updated in case
the parent actor moved.
Connecting to the "notify::position" signal, which the above commit also
did is now superflous though because position changes will queue a
relayout and the actors allocation will change during the next
allocation cycle, notifying the "allocation" property which we also
listen to.
So save some resources and stop listening to that signal.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1235
A DMA buffer might not be able to scanout, and in that case the import
with GBM_BO_USE_SCANOUT will fail. Handle that by failing to scanout,
effectively falling back to compositing.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1261
The shell uses the PID of windows to map them to apps or to find out
which window/app triggered a dialog. It currently fails to do that in
some situations on Wayland, because meta_window_get_pid() only returns a
valid PID for x11 clients.
So use the client PID instead of the X11-exclusive _NET_WM_PID property
to find out the PID of the process that started the window. We can do
that by simply renaming the already existing
meta_window_get_client_pid() API to meta_window_get_pid() and moving
the old API providing the _NET_WM_PID to meta_window_get_netwm_pid().
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1180
Since we're now connecting to one more signal of MetaWaylandOutput, keep
signal connections in one place and move connecting the
"output-destroyed" signal to surface_entered_output() and disconnecting
it to surface_left_output().
This also allows us to use the "outputs_to_destroy_notify_id" as a
simple set and rename it to "outputs".
While at it, also use g_hash_table_destroy() instead of
g_hash_table_unref() since destroy is more clear than unref and does the
same thing in this case.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1230
When hotplugging a new monitor, we recreate all the MetaWaylandOutputs
and need to emit leave events to the surfaces for the old wl_outputs and
enter events for the newly created ones.
There's a race condition though: We might update the monitors a surface
is on (and thus emit enter/leave events for the wl_outputs) before the
Wayland client is registered with the new wl_output (ie. the
bind_output() callback of MetaWaylandOutput was called), which means we
don't send an enter event to the client in surface_entered_output().
Since MetaWaylandSurface now has the MetaWaylandOutput in its outputs
hashtable, it thinks the client has been notified and won't send any
more enter events.
To fix that, make MetaWaylandOutput emit a new signal "output-bound"
when a client bound to the output and make all surfaces which are on
that output listen to the signal. In the signal handler compare the
newly added client to the client the surface belongs to, and if it's the
same one, send an enter event to that client.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1230
The "output-destroyed" signal is used for notifying MetaWaylandSurfaces
that an output they are shown just got invalid (for example because a
monitor hotplug happened).
While we delay the destroying of outputs by 10 seconds since commit
1923db97 because of a race-condition, it doesn't make sense to wait 10
seconds until we let surfaces know that an output was destroyed.
So move the emission of the "output-destroyed" signal to
make_output_inert(), which is called before we start the 10 seconds
delay.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1230
Instead of having everything clumped at MetaWaylandDataManager,
split the primary selection to its own struct. This manager is
handled separately from wl_data_device_manager and other selection
managers, so they would be able to interoperate between them, even.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1193
This is still an openly defined struct, as we will need accessed
by "subclasses". Same principle applies than with the
MetaWaylandDataSource refactor, this is not meant to introduce
functional changes, so just go with it.
On the bright side, the interactions are now clearer, so it could
be made saner in the future.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1193
The split wasn't 100% clean, and some extra private API had to be
added for it (but well, looking at the API, it's already evident
there's a cleanup/streamlining task due). This is meant to be a
refactor with no functional changes, so just go with it.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1193
We already have a signal callback that translates selection ownership changes to
data_device/primary .selection events. Given both will be run when a data source
is being replaced, and this event emission being deleted is kinda short sighted
in that in only knows about Wayland, rely entirely on MetaSelection::owner-changed
emission.
Fixes spurious .selection(null) events being sent when a compositor-local source
takes over the selection without the focus changing (eg. screenshot to clipboard).
Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/1160https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1204
We are meant to send a .cancelled event after the drop is performed
in certain situations, but only for version>3 clients. Since this is
all version 3 business, only set the drop_performed flag for v3
clients. This drops the need to perform version checks at the time
of cancelling (which is present for other usecases in v1).
Fixes emission of wl_data_source.cancelled for v1 clients.
Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/1177https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1203
This will check whether the current backing buffer is compatible with
the primary plane of the passed CoglOnscreen. Since this will extend the
time before a buffer is released, the MetaWaylandBufferRef is swapped
and orphaned if a new buffer is committed before the previous one was
released. It'll eventually be released, usually by the next page flip
callback.
Currently implemented for EGLImage and DMA-BUF buffer types.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/798
Advertising support for modifiers means we will most likely not not be
able to scan out client buffers directly, meaning it just as likely that
we won't be able to scan out even fullscreen windows without atomic KMS.
When we have atomic support, we should advertise support for modifiers
if atomic is used to drive the CRTCs, as we by then can check whether we
can scan out directly, place in an overlay plane, etc.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/798
Currently a buffer use count always reaches zero before it is replaced.
This is due to the fact that at the point a new buffer is attached, the
last potential user releases it (the stage) since the currently
displayed frame has a composited copy of the buffer.
This may however change, if a buffer is scanned out directly, meaning it
should not be released until the page flip callback is invoked.
Prepare for this by making the buffer reference a heap allocated struct,
enabling us to keep a pointer to it longer than the buffer is attached.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/798
On VT switch, the devices are removed, which means for Wayland disabling
the keyboard.
When the keyboard is disabled, the associated `xkb_state` is freed and
recreated whenever the keyboard is re-enabled when switching back to the
compositor VT.
That means the `xkb_state` for Wayland is lost whereas the same for
clutter is kept, which causes to a discrepancy with locked modifiers on
VT switch.
To avoid that issue, preserve the XKB info only to dispose it when the
keyboard is eventually finalized.
Closes: https://gitlab.gnome.org/GNOME/mutter/issues/344https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1185
IBusInputContext/ClutterInputFocus/GtkIMContext all go for offset+len
for their ::delete-surrounding signals, with offset being a signed int
(neg. to delete towards left of selection, pos. to delete towards right
of selection) and len being an unsigned int from the offset (and
presumably, skipping the current selection).
The text-input protocols however pass in this event two unsigned integers,
one being the length of text to delete towards the left of the selection,
and another the length of text to delete towards the right of the selection.
To translate properly these semantics, positive offsets shouldn't account
for before_length, and negative offset+len shouldn't account for after_length.
The offset/length approach may of course represent deletions that are
detached from the current cursor/selection, we simply delete the whole range
from the cursor/selection positions then.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/517
The input method can assign a negative value to
clutter_input_method_delete_surrounding() to move the cursor to the left.
But Wayland protocol accepts positive values in delete_surrounding() and
GTK converts the values to the negative ones in
text_input_delete_surrounding_text_apply().
https://gitlab.gnome.org/GNOME/mutter/issues/539
When resizing a window interactively, we'll set a grab operation and a
grab window, among other things. If we're resizing (including setting
initial size, i.e. mapping) another window, that didn't change position,
don't use the gravity of the grab operation when resizing our own
window.
This fixes an issue with jumpy popup position when moving a previously
mapped gtk popover.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/999
This is so that cogl-trace.h can start using things from cogl-macros.h,
and so that it doesn't leak cogl-config.h into the world, while exposing
it to e.g. gnome-shell so that it can make use of it as well. There is
no practical reason why we shouldn't just include cogl-trace.h via
cogl.h as we do with everything else.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/1059
Both IBus and ClutterInputFocus work in character offsets for the cursor
position in the preedit string. However the zwp_text_input protocol does
define the preedit string cursor offset to be in bytes.
Fixes client bugs in representing the caret within the preedit string,
as we were clearly giving the wrong offset.
Fixes: https://gitlab.gnome.org/GNOME/gtk/issues/2517https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1132
We send configure events for state changes e.g. for `appears-focused`,
etc. What we don't want to do is to do this for popup windows, as in
Wayland don't care about this state.
When the focus mode was configured to "sloppy focus" we'd get
`appears-focused` state changes for the popup window only by moving the
mouse cursor around, and while a popup may care about focus, it does not
care about related appearance, as there is no such state in xdg_popup.
What these state changes instead resulted in was absolute window
configuration events, intended for toplevel (xdg_toplevel) windows. In
the end this caused the popup to be positioned aginst at (0, 0) of the
parent window, as the assumptions when the configuration of the popup
was acknowledged is that it had received a relative position window
configuration.
Fix this by simply ignoring any state changes of the window if it is a
popup, meaning we won't send any configuration events intended for
toplevels for state changes. Currently we don't have any way to know
this other than checking whether it has a placement rule. Cleaning up
MetaWindow creation is left to be dealt with another day.
Fixes: https://gitlab.gnome.org/GNOME/mutter/issues/1103https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1122
There is a race where an output can be used as a fullscreen target, but
it has already been removed due to a hotplug. Handle this gracefully by
ignoring said output in such situations.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1120
For X11 clients running on Wayland, the actual texture is set by
Xwayland.
The shape, input and opaque regions, however are driven by X11
properties meaning that those may come at a different time than the
actual update of the content.
This results in black areas being visible at times on resize with
Xwayland clients.
To make sure we update all the regions at the same time the buffer is
updated, update the shape, input and opaque regions when the texture is
committed from when the Xwayland surface state is synchronized.
That fixes the remaining black areas being sometimes visible when
resizing client-side decorations windows on Xwayland.
Closes: https://gitlab.gnome.org/GNOME/mutter/issues/1007https://gitlab.gnome.org/GNOME/mutter/merge_requests/1091
If we don't force the placement, we enter the constrain machinery with
the position (0, 0), meaning we always get the "current work area" setup
to correspond to whatever logical monitor was at that position.
Avoid this by doing the same as "meta_window_force_placement()" and set
"window->calc_placement" to TRUE while move-resizing, causing the
move-resize to first calculate the initial position.
Fixes: https://gitlab.gnome.org/GNOME/mutter/issues/1098https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1110
This commit completes the implementation of `xdg_wm_base` version 3,
which introduces support for synchronized implicit and explicit popup
repositioning.
Explicit repositioning works by the client providing a new
`xdg_positioner` object via a new request `xdg_popup.reposition`. If the
repositioning is done in combination with the parent itself being
reconfigured, the to be committed state of the parent is provided by the
client via the `xdg_positioner` object, using
`xdg_positioner.set__parent_configure`.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/705
This sets the `is_reactive` flag on the window placement rules, causing
the popups to be reconfigured as they are affected by environmental
changes, such as the parent moving in a way making the popup partially
offscreen.
As with synchronization, the implementation is dormant, as the
version of the advertised global isn't bumped yet, as the new protocol
version is not yet fully implemented.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/705
This commits adds support on the MetaWindow and constraints engine side
for asynchronously repositioning a window with a placement rule, either
due to environmental changes (e.g. parent moved) or explicitly done so
via `meta_window_update_placement_rule()`.
This is so far unused, as placement rules where this functionality is
triggered are not yet constructed by the xdg-shell implementation, and
no users of `meta_window_update_placement_rule()` exists yet.
To summarize, it works by making it possible to produce placement rules
with the parent rectangle a window should be placed against, while
creating a pending configuration that is not applied until acknowledged
by the client using the xdg-shell configure/ack_configure mechanisms.
An "temporary" constrain result is added to deal with situations
where the client window *must* move immediately even though it has not yet
acknowledged a new configuration that was sent. This happens for example
when the parent window is moved, causing the popup window to change its
relative position e.g. because it ended up partially off-screen. In this
situation, the temporary position corresponds to the result of the
movement of the parent, while the pending (asynchronously configured)
position is the relative one given the new constraining result.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/705
MetaGravity is an enum, where the values match the X11 macros used for
gravity, with the exception that `ForgetGravity` was renamed
`META_GRAVITY_NONE` to have less of a obscure name.
The motivation for this is to rely less on libX11 data types and macros
in generic code.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/705
A placement rule placed window positions itself relative to its parent,
thus converting between relative coordinates to absolute coordinates,
then back to relative coordinates implies unwanted restrictions for
example when the absolute coordinate should not be calculated againts
the current parent window position.
Deal with this by keeping track of the relative position all the way
from the constraining engine to the move-resize window implementation.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/705
To organize things a bit better, put the fields related to the placement
rule state in its own anonymous struct inside MetaWindow. While at it,
rename the somewhat oddly named variable that in practice means the
current relative window position.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/705
After popup placement rules have gone through the constraints engine has
ended up resulting in an actual move, pass the window configuration down
the path using relative coordinates, as that is what the next layer
(xdg-shell implementation) actually cares about.
In the future, this will also be helpful when the configured position is
not against the current state of the parent.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/705
meta_window_wayland_finish_move_resize() inhibited window moves to be
finished if there was a resize grab active at the time, in order to
handle window resizing. Change this to only affect the grabbed window
itself, so that e.g. a popup can be positioned according to a pending
configuration while there is an active resize grab.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/705
This is used by GDK and the X11 bits, but may also be used for
other initialization services we might need to run along with
Xwayland initialization.
However, as the -initfd argument in Xwayland is a fairly new
feature, add some meson build-time checks so that the feature
is handled transparently while allowing to explicitly set/unset
it.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/945
We artificially made Xwayland initialization synchronous, as we used
to rely on MetaX11Display and other bits during meta_display_open().
With support for Xwayland on demand and --no-x11, this is certainly
not the case.
So drop the main loop surrounding Xwayland initialization, and turn
it into an async operation called from meta_display_init_x11(). This
function is turned then into the high-level entry point that will
get you from no X server to having a MetaX11Display.
The role of meta_init() in Xwayland initialization is thus reduced
to setting up the sockets. Notably no processes are spawned from here,
deferring that till there is a MetaDisplay to poke.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/944
This ATM completes the task right away, but we will want to do
further things here that are asynchronous in nature, so prepare
for this operation being async.
Since the X11 backend doesn't really need this, make it go on
the fast lane and open the MetaX11Display right away, the case
of mandatory Xwayland on a wayland session is now handled
separately.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/944
Remove the rather useless callback function that's currently used for
handling the "visibility-changed" signal and instead connect to the
signal using `g_signal_connect_swapped()`.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/1077
`meta_xwayland_surface_get_relative_coordinates()` may cause a crash if
the Xwayland surface has no window associated.
That can be observed when using drag and drop from an X11 window to a
Wayland native window:
```
at src/core/window.c:4503
at src/wayland/meta-xwayland-surface.c:200
at src/wayland/meta-wayland-surface.c:1517
at src/wayland/meta-wayland-pointer.c:1048
at src/wayland/meta-wayland-pointer.c:840
at src/wayland/meta-wayland-pointer.c:865
at src/wayland/meta-wayland-pointer.c:954
at src/wayland/meta-wayland-pointer.c:456
at src/wayland/meta-wayland-pointer.c:993
at src/wayland/meta-wayland-data-device.c:1004
at src/wayland/meta-wayland-data-device.c:1278
at src/wayland/meta-xwayland-dnd.c:326
```
Check if the xwayland surface has an associated MetaWindow prior to get
its buffer rect.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/1073
There are two surface roles owning a MetaWindow: MetaWaylandShellSurface
(basis of MetaWaylandXdgToplevel, MetaWaylandXdgPopup,
MetaWaylandWlShellSurface, etc), and MetaXwaylandSurface.
With these two role types, the MetaWindow has two different types of
life times. With MetaWaylandShellSurface, the window is owned and
managed by the role itself, while with MetaXwaylandSurface, the
MetaWindow is tied to the X11 window, while the Wayland surface and its
role plays more the role of the backing rendering surface.
Before, for historical reasons, MetaWindow was part of
MetaWaylandSurface, even though just some roles used it, and before
'wayland: Untie MetaWindowXwayland lifetime from the wl_surface' had
equivalent life times as well. But since that commit, the management
changed. To not have the same fied in MetaWaylandSurface being managed
in such drastically different ways, rearrange it so that the roles that
has a MetaWindow themself manages it in the way it is meant to; meaning
MetaWaylandShellSurface practically owns it, while with Xwayland, the
existance of a MetaWindow is tracked via X11.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/835
The role determines how a relative coordinate is calculated. More
specifically, using clutters API to transform coordinates is only
accurate right after a clutter layout pass but this function is used
e.g. to deliver pointer motion events which can happen at any time. This
isn't a problem for Wayland clients since they don't control their
position, but X clients do and we'd be sending outdated coordinates if a
client is moving a window in response to motion events.
This was already done already, but now move the Xwayland specific logic
to the Xwayland surface role, keeping the generic transformation logic
in the generic actor surface role.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/835
The shell surface role is the one where subsurfaces may exist, and it
has direct relation to the MetaWindowActorWayland which currently has
the subsurface stacking logic.
Instead of directly finding the window actor when dealing with
subsurfaces, notify the parent surface that the subsurface state
changed, so that it can outsource the application of this information to
the role. For subsurface roles, this simply means forward upward to the
parent; for shell surface roles, this means regenerate the surface actor
layering.
This allows us to move away from accessing the window directly from the
surface, which in turn allows us to change the ownership structure of
windows.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/835
XWayland clients get their opaque region set from their window, not the
surface. Doing both resulted in the surface constantly overwriting the
opaque region - effectively disabling culling of XWayland clients.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/1049
The actors of Wayland subsurfaces are set to be reactive on creation,
when receiving the `wl_subcompositor.get_subsurface` request.
However, if a client creates several subsurfaces and then creates the
xdg_toplevel object after, the previous subsurface actors are reset.
As a result, Clutter picking will skip and ignore those actors in
`clutter_actor_should_pick_paint()` because they aren't marked as
reactive anymore.
An example of such a client being affected by this issue is SCTK, the
Rust library implementing client side decorations for Wayland used
internally by winit and alacritty.
Move the `set_reactive()` call from `get_subsurface()` to the subsurface
`sync_actor_subsurface_state()` vfunc to make sure those remain reactive
even after `xdg_surface.get_toplevel` is invoked.
Closes: https://gitlab.gnome.org/GNOME/mutter/issues/1024https://gitlab.gnome.org/GNOME/mutter/merge_requests/1040
Using `-Dnative_backend=false` caused build failure due to a missing
(implicit) definition of `META_IS_BACKEND_X11`. But if we define it
properly then that just leaves some of the function's locals uninitialized
and it will never work anyway. Just return unconditionally if there's no
native backend to initialize the variables.
Closes: https://gitlab.gnome.org/GNOME/mutter/issues/1025
Interoperation between wl_data_device_manager v1 and v3 got broken
at some point. Ensure that we resort to the "copy" action if either
the drop site or the drag source are from a client that requested v1.
Closes: https://gitlab.gnome.org/GNOME/mutter/issues/965
Just go ATM through backend checks, and looking up directly the
native event data, pretty much like the rest of the places do that...
Eventually would be nice to have this information in ClutterEvent,
but let's not have it clutter the MetaBackend class.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/852
When a Wayland window is mapped or unmapped, the Wayland compositor is
expected to send the coorespoindign `wl_pointer` enter/leave events to
the affected clients.
To do so, mutter calls `meta_wayland_compositor_repick()` which
eventually calls `meta_wayland_pointer_repick()` and
`repick_for_event()`.
If pointer input device has not been updated yet, the old clutter actor
is picked and no enter/leave event is emitted.
Make sure we update the pointer input device prior to do the repick to
get the actual `ClutterActor` under the pointer.
Closes: https://gitlab.gnome.org/GNOME/mutter/issues/1016https://gitlab.gnome.org/GNOME/mutter/merge_requests/1026
When mapping/unmapping windows, an animation may be played which can
change the actual actor size and location, hence defeating picking if
done too early.
Make sure we repick when the affects are completed, once the actor is
sized and placed.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/1026
In XDND, we just get a hint on XdndPosition about what's the action
chosen by the user. Make the data source actions the full set on
XdndEnter (as we can't know better), and pass the hint in XdndPosition
as the user chosen action as it should be.
Makes Wayland drop sites aware of the user action as per XDND with X11
drag sources, and still makes modifiers during DnD work.
https://gitlab.gnome.org/GNOME/mutter/issues/974https://gitlab.gnome.org/GNOME/mutter/merge_requests/1005
The acked configuration is removed from the pending configuration list
by acquire_acked_configuration(), but finish_move_resize() does not free
the data after applying the configuration.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/1020
To address the black shadows that sometimes show during resize with
Xwayland, we need to update the window shape regardless of the frozen
status of the window actor.
However, plain Xorg does not need this, as resized windows do not clear
to black, so add a new vfunc to window/x11 to indicate whether or not
the backing windowing system (either plain X11 or Xwayland) would
require the shape to be always updated.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/942
Xwayland may post damages for an X11 window as soon as the frame
callback is triggered, while the X11 window manager/compositor has not
yet finished updating the windows.
If Xwayland becomes compliant enough to not permit updates after the
buffer has been committed (see [1]), then the partial redraw of the X11
window at the time it was posted will show on screen.
To avoid that issue, the X11 window manager can use the X11 property
`_XWAYLAND_ALLOW_COMMITS` to control when Xwayland should be allowed to
post the pending damages.
Add `freeze_commits()` and `thaw_commits()` methods to `MetaWindowX11`
which are a no-op on plain X11, but sets `_XWAYLAND_ALLOW_COMMITS` on
the toplevel X11 windows running on Xwayland.
[1] https://gitlab.freedesktop.org/xorg/xserver/merge_requests/316
See-also: https://gitlab.gnome.org/GNOME/mutter/merge_requests/855https://gitlab.gnome.org/GNOME/mutter/merge_requests/942
This avoids using bogus geometric values from an unmapped actor to
determine whether an actor is on a logical monitor or not. This would
happen when committing to a subsurface of a yet to be mapped toplevel.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/961
Without 'wayland/surface-actor: Reset and sync subsurface state when
resetting' this test would fail.
This also adds a simple framework for testing lower level Wayland
semantics.
In contrast to the test-client and test-driver framework, which uses
gtk and tests mostly window management related things, this framework is
aimed to run Wayland clients made to test a particular protocol flow,
thus will likely consist of manual lower level Wayland mechanics.
A private protocol is added in order to help out clients do things they
cannot do by themself. The protocol currently only consists of a request
meant to be used for getting a callback when the actor of a given
surface is eventually destroyed. This is different from the wl_surface
being destroyed due to window destroy animations taking an arbitrary
amount of time. It'll be used by the first test added in the next
commit.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/961
As with most other state that ends up being pushed to the actor and the
associated shaped texture, also push the texture and the corresponding
metadata from the actor surface. This fixes an issue when a toplevel
surface was reset, where before the subsurface content was not properly
re-initialized, as content state synchronization only happened on
commit, not when asked to synchronize.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/961
A actor surface may be reset by an xdg_toplevel if a NULL buffer is
attached. This should reset the actor state of the toplevel to an empty
state, while unmapping the previous actor. Subsurfaces, however, should
stay intact, including their relationship to the toplevel. They should
also not be yanked away from the actor of the actor surface prior to it
resetting, so that a window-destroy animation can include the subsurface
actor.
This fixes a potential crash when a subsurface tries to commit to its
wl_surface after the destroy animation of the toplevel has finished, as
the actor would at that point have been destroyed and cleared from the
actor surface struct, causing a segmentation fault.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/961
Similar to wl_list_foreach(), add
META_WAYLAND_SURFACE_FOREACH_SUBSURFACE() that iterates over all the
subsurfaces of a surface, without the caller needing to care about
implementation details, such as leaf nodes vs non-leaf nodes.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/961
While it's not very relevant now, as we would rarely create it anyway
since the buffer nor texture never changes for a surface, it will be in
the future, as the actor state (including its content,
MetaShapedTexture) will be synchronized by the MetaWaylandActorSurface
at a later point in time, and not by MetaWaylandSurface, at state
application time.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/961
'xwayland: Do not queue frame callbacks unconditionally' changed the
frame callback behavior of Xwayland surfaces so that they behave the
same way as other actor surfaces (e.g. xdg-shell ones), except for the
case when they are initially assigned.
Remove this special casing as well including the now incorrect comment,
so that the Xwayland surfaces behave the same as the others in this
regard also when assigning.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/964
The vfunc is not called when a surface commits its state, but when the
state is applied. Make this clearer by changing the name to
"apply_state" (and "pre_apply_state").
https://gitlab.gnome.org/GNOME/mutter/merge_requests/907
This changes how asynchronous window configuration works. Prior to this
commit, it worked by MetaWindowWayland remembering the last
configuration it sent, then when the Wayland client got back to it, it
tried to figure out whether it was a acknowledgment of the configuration
or not, and finish the move. This failed if the client had acknowledged
a configuration older than the last one sent, and it had hacks to
somewhat deal with wl_shell's lack of configuration serial numbers.
This commits scraps that and makes the MetaWindowWayland take ownership
of sent configurations, including generating serial numbers. The
wl_shell implementation is changed to emulate serial numbers (assuming
each commit acknowledges the last sent configure event). Each
configuration sent to the client is kept around until the client one. At
this point, the position used for that particular configuration is used
when applying the acknowledged state, meaning cases where we have
already sent a new configuration when the client acknowledges a previous
one, we'll still use the correct position for the window.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/907
Historically, wl_shell clients used to pretend the input region was
equivalent to the window geometry, so for "correctness" lets do that
here too. This makes wl_shell clients with drop shadow behave marginally
better than before.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/907
This moves the cached subsurface surface state into the generic
MetaWaylandSurface namespace. Eventually it'll be used by other surface
roles which as well aim to implement synhcronization.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/907
The name didn't communicate it was about surface state, and it somewhat
confusingly had the name "pending" in it, which could be confused with
the fact that while it's used to collect pending state, it's also used
to cache previously committed pending state.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/907
With the eventual aim of exposing the internals of MetaWaylandSurface
outside of meta-wayland-surface.c, make users of the pending state use a
helper to fetch it. While at it, rename the struct field to something
more descriptive.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/907
The intention of meta_window_wayland_move_resize() is to finish a
move-resize requested previously, e.g. by a state change, or a
interactive resize. Make the function name carry this intention, by
renaming it to meta_window_wayland_finish_move_resize().
https://gitlab.gnome.org/GNOME/mutter/merge_requests/907
It's not always clear how the dma-buf functions work (e.g. where memory
is allocated) without actually going in-depth in the code. This just
adds a few commments to more quickly gain understanding.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/871
While most of the code to compute a window's layer isn't explicitly
windowing backend specific, it is in practice: On wayland there are
no DESKTOP windows(*), docks(*) or groups.
Reflect that by introducing a calculate_layer() vfunc that computes
(and sets) a window's layer.
(*) they shall burn in hell, amen!
https://gitlab.gnome.org/GNOME/mutter/merge_requests/949
This is inspired by 98892391d7 where the usage of
`g_signal_handler_disconnect()` without resetting the corresponding
handler id later resulted in a bug. Using `g_clear_signal_handler()`
makes sure we avoid similar bugs and is almost always the better
alternative. We use it for new code, let's clean up the old code to
also use it.
A further benefit is that it can get called even if the passed id is
0, allowing us to remove a lot of now unnessecary checks, and the fact
that `g_clear_signal_handler()` checks for the right type size, forcing us
to clean up all places where we used `guint` instead of `gulong`.
No functional changes intended here and all changes should be trivial,
thus bundled in one big commit.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/940
On wl_data_source destruction we used to indirectly unset the DnD selection
owner via the wl_resource destructor triggering the destruction of the
MetaWaylandDataSource, which would be caught through the weak ref set by
the MetaWaylandDragGrab.
This works as long as the grab is held, however we have a window between
the button being released and the drop site replying with
wl_data_offer.finish that the MetaWaylandDataSource is alive, but its
destruction wouldn't result in the call chain above to unsetting the DnD
source.
In other selection sources, we let the MetaWaylandDataDevice hold the
"ownership" of the MetaWaylandDataSource, and its weak ref functions unset
the respective MetaSelection owners. Do the same here, so the
MetaWaylandDataSource destruction is listened for all its lifetime.
Closes: https://gitlab.gnome.org/GNOME/mutter/issues/591
This is wrong for both clipboard and DnD, as the selection source
will still be able to focus another surface, and churn another
wl_offer.
We should just detach the data offer from the data source in this
case, and let the source live on. However, we should still check
that there is a source and an offer to finish DnD, do that when
handling the drop operation instead.
https://gitlab.gnome.org/GNOME/mutter/issues/591
