Add wlr_single_pixel_buffer_v1_try_from_buffer() and move `struct
wlr_single_pixel_buffer_v1` to wlr_buffer.h. This allows other code to
find out if a wlr_buffer is a single-pixel buffer and, if so, find out
what color it is.
Remove unneeded includes of wlr_output.h from wlr_compositor.h and
wlr_cursor.h (unneeded now that we forward-declare struct wlr_surface)
and put the actually-required includes in the right places.
wlr_compositor.h contains references to `struct wlr_surface` in function
arguments before it actually defines it. This generally works because
wlr_compositor.h includes wlr_output.h which contains a
forward-declaration for `struct wlr_surface` (despite not actually
referencing it).
This is all pretty weird, and gives very confusing errors if you manage
to end up with wlr_output.h including wlr_compositor.h (eg. via an
indirect route) so make it less weird.
The old approach of using a signal is fundamentally broken for a common
usecase: When the waiter is ready, it's common to immediately finish and
free any resources associated with it.
Because of the semantics of wl_signal_emit_mutable() this is UB.
wl_signal_emit_mutable() always excepts that the waiter hasn't been freed
until the signal has finished being emitted.
Instead of over engineering the solution, let's just add a callback required
by wlr_drm_syncobj_timeline_waiter_init(). In this callback, the implementation
is free to finish() or free() any resource it likes.
This fixes a problem where an outdated surface input region was used to
compute the effective confinement region.
Additionally, this commit fixes a bug in pointer_constraint_create()
which caused the initial region to not be applied immediately.
This is a breaking change: set_region is now emitted before the role
commit hook is called, and it's not emitted if the region hasn't
actually changed.
udmabuf can create a DMA-BUF backed by a memfd. This is useful
when running with a software implementation of GL/Vulkan: the memfd
can be passed to the parent compositor via wl_shm and the DMA-BUF
can be imported via the usual APIs into GL/Vulkan.
A footgun in the wlr_buffer API is that there's no difference
between acquiring a buffer and increasing the lock count. In other
words, transitioning a buffer from the released state to the
acquired state is not explicit. This may result in hard-to-debug
failures if there is a dangling released wlr_buffer somewhere
(e.g. wlr_client_buffer.source [1]) and some piece of code calls
wlr_buffer_lock(). In that case, the buffer will be acquired and
released again. In the context of a wlr_buffer issued from a
Wayland protocol wl_buffer object, this can cause the underlying
memory to be used after wl_buffer.release has been sent to the
client, and a double wl_buffer.release event to be sent.
Make it so acquiring a buffer is an explicit operation to make sure
the caller means the state transition and is prepared for a new
release event. wlr_buffer_acquire() forbids calls on already-acquired
buffers, and wlr_buffer_lock() now forbids calls on released buffers.
[1]: https://gitlab.freedesktop.org/wlroots/wlroots/-/merge_requests/4904
