Spell out exactly when a client may re-use a wl_buffer or its backing
storage. Mention the optimization for GL-compositor with wl_shm-clients.
Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>
This change breaks the protocol.
The current protocol is racy in that updates to surface content and
surface state (e.g. damage, input and opaque regions) are not guaranteed
to happen at the same time. Due to protocol buffering and handling
practices, the issues are very hard to trigger.
Committing damage to a surface at arbitrary times makes it hard to
track when the wl_buffer is being read by the server, and when it is
safe to overwrite (the case of wl_shm with a single buffer reused
constantly).
This protocol change introduces the concept of double-buffered state.
Such state is accumulated and cached in the server, unused, until the
final commit request. The surface will receive its new content and apply
its new state atomically.
A wl_surface.commit request is added to the protocol. This is thought to
be more clear, than having wl_surface.attach committing implicitly, and
then having another request to commit without attaching, as would be
required for a GL app that wants to change e.g. input region without
redrawing.
When these changes are implemented, clients do not have to worry about
ordering damage vs. input region vs. attach vs. ... anymore. Clients set
the state in any order they want, and kick it all in with a commit.
The interactions between wl_surface.attach, (wl_surface.commit,)
wl_buffer.release, and wl_buffer.destroy have been undocumented. Only
careful inspection of the compositor code has told when a wl_buffer is
free for re-use, especially for wl_shm and wrt. wl_surface.damage.
Try to clarify how it all should work, and what happens if the wl_buffer
gets destroyed.
An additional minor fix: allow NULL argument to
wl_surface.set_opaque_region. The wording in the documentation already
implied that a nil region is allowed.
Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>
In most cases the pointer equality test is sufficient. However, in
some cases, depending on how things are split across shared objects,
we can end up with multiple instances of the interface metadata
constants. So if the pointers match, the interfaces are equal, if
they don't match we have to compare the interface names.
Replace the outdated section about drag and drop support with a
rewritten section covering the data source/offer mechanism and
wl_data_device, explaining how selection and drag ang drop works.
On the client side where we queue up multiple events before dispatching, we
need to look up the receiving proxy and argument proxies immediately before
calling the handler. Between queueing up multiple events and eventually
invoking the handler, previous handlers may have destroyed some of the
proxies.
The only way to make the global object listener interface thread safe is to
make it its own interface and make different listeners different wl_proxies.
The core of the problem is the callback we do when a global show up or
disappears, which we can't do with a lock held. On the other hand we can't
iterate the global list or the listener list without a lock held as new
globals or listeners may come and go during the iteration.
Making a copy of the list under the lock and then iterating after dropping
the lock wont work either. In case of the listener list, once we drop the
lock another thread may unregister a listener and destroy the callbackk
data, which means that when we eventually call that listener we'll pass it
free memory and break everything.
We did already solve the thread-safe callback problem, however. It's what
we do for all protocol events. So we can just make the global registry
functionality its own new interface and give each thread its own proxy.
That way, the thread will do its own callbacks (with no locks held) and
destroy the proxy when it's no longer interested in wl_registry events.
We used to special case this because of the untyped new-id argument in
the bind request. Now that the scanner can handle that, we can
remove the special case.
Switching to the generated stubs does bring an API change since we now
also take the interface version that the client expects as an argument.
Previously we would take this from the interface struct, but the
application may implement a lower version than what the interface struct
provides. To make sure we don't try to dispatch event the client
doesn't implement handlers for, we have to use a client supplied version
number.
This makes the scanner generate the code and meta data to send the
interface name and version when we pass a typeless new_id. This way, the
generic factory mechanism provided by wl_display.bind can be provided by
any interface.
This introduces wl_event_queue, which is what will make multi-threaded
wayland clients possible and useful. The driving use case is that of a
GL rendering thread that renders and calls eglSwapBuffer independently of
a "main thread" that owns the wl_display and handles input events and
everything else. In general, the EGL and GL APIs have a threading model
that requires the wayland client library to be usable from several threads.
Finally, the current callback model gets into trouble even in a single
threaded scenario: if we have to block in eglSwapBuffers, we may end up
doing unrelated callbacks from within EGL.
The wl_event_queue mechanism lets the application (or middleware such as
EGL or toolkits) assign a proxy to an event queue. Only events from objects
associated with the queue will be put in the queue, and conversely,
events from objects associated with the queue will not be queue up anywhere
else. The wl_display struct has a built-in event queue, which is considered
the main and default event queue. New proxies are associated with the
same queue as the object that created them (either the object that a
request with a new-id argument was sent to or the object that sent an
event with a new-id argument). A proxy can be moved to a different event
queue by calling wl_proxy_set_queue().
A subsystem, such as EGL, will then create its own event queue and associate
the objects it expects to receive events from with that queue. If EGL
needs to block and wait for a certain event, it can keep dispatching event
from its queue until that events comes in. This wont call out to unrelated
code with an EGL lock held. Similarly, we don't risk the main thread
handling an event from an EGL object and then calling into EGL from a
different thread without the lock held.
The update callback for the file descriptors was always a bit awkward and
un-intuitive. The idea was that whenever the protocol code needed to
write data to the fd it would call the 'update' function. This function
would adjust the mainloop so that it polls for POLLOUT on the fd so we
can eventually flush the data to the socket.
The problem is that in multi-threaded applications, any thread can issue
a request, which writes data to the output buffer and thus triggers the
update callback. Thus, we'll be calling out with the display mutex
held and may call from any thread.
The solution is to eliminate the udpate callback and just require that
the application or server flushes all connection buffers before blocking.
This turns out to be a simpler API, although we now require clients to
deal with EAGAIN and non-blocking writes. It also saves a few syscalls,
since the socket will be writable most of the time and most writes will
complete, so we avoid changing epoll to poll for POLLOUT, then write and
then change it back for each write.
strlen() doesn't include the terminating NUL. Therefore when allocating a
block of memory to hold something equivalent to the length of the string we
must increment to take the NUL byte into consideration.
Signed-off-by: Rob Bradford <rob@linux.intel.com>
My vim spell checker is able to find typos of xml files after adding "syn spell
toplevel" to ~/.vim/after/syntax/xml.vim
aah, and Wayland is capital letter :)
Signed-off-by: Tiago Vignatti <tiago.vignatti@intel.com>
We really shouldn't add the man-pages when HAVE_XSLTPROC is not true so
move it into the if-clause.
But declare the automake-variables outside of the if-clause to avoid
automake complaints.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
This adds a man-page infrastructure based on Docbook XML files. This
allows us to integrate the man-pages into the publican books later. An
example page for wl_display_connect() (with an alias
wl_display_connect_to_fd()) is also added.
Feel free to add more man-pages. Function calls are put in man3 and
overview pages into man7. All pages (including aliases) have to be added
to the Makefile.
Docbook does generate aliases automatically from the additional names that
were put in the XML file. However, a small SED script is needed to fixup
the include-paths in the generated troff files. If someone knows how to
avoid that (or even install them gzip'ped), please fix it up.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
When integrating the wayland event-loop into another event-loop, we
currently have no chance of checking whether there are pending idle
sources that have to be called. This patch exports the
"dispatch_idle_sources()" call so other event loops can call this before
going to sleep. This is what wl_event_loop_dispatch() currently does so we
simply allow external event-loops to do the same now.
To avoid breaking existing applications, we keep the call to
dispatch_idle_sources() in wl_event_loop_dispatch() for now. However, if
we want we can remove this later and require every application to call
this manually. This needs to be discussed, but the overhead is negligible
so we will probably leave it as it is.
This finally allows to fully integrate the wayland-server API into
existing event-loops without any nasty workarounds.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
wl_client_add_resource() used to return no error even though the new
resource wasn't added to the client. This currently makes it very easy to
DOS weston by simply posting thousands of "create_surface" requests with
an invalid ID. Weston simply assumes the wl_client_add_resource() request
succeeds but will never destroy the surface again as the "destroy" signal
is never called (because the surface isn't linked into the wl_map).
This change makes wl_client_add_resource() return the new ID of the added
object and 0 on failure. Servers (like weston) can now correctly
immediately destroy the surface when this call fails instead of leaving
the surface around and producing memory-leaks.
Instead of returning -1 on failure and 0 on success, I made it return the
new ID as this seems more appropriate. We can directly use it when calling
it with new_id==0.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
There is really no need to increment "n" if we never read the value. The
do-while() loop overwrites the value before it is read the first time.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
This theme is loaded when the specified cursor theme can not be found.
These cursors are extracted from the xorg sources and transformed into
raw ARGB data by a small helper program (commited separately).
This finalizes Robert Bradfords patch to allow NO_ASSERT_LEAK_CHECK
environment variable to disable leak checks in unit tests.
Signed-off-by: U. Artie Eoff <ullysses.a.eoff@intel.com>
This patch adds a few more directories to search for xcursor themes.
Along with the weston patch, this adds the ability to configure weston
to use an X11 cursor theme. Previously, wayland cursor would just look
in the icons and pixmaps directories for cursor images to load. This
adds the ability to also search in the x cursors directory.
Expose these to other files using wayland-private.h, so wayland-client.c
can walk NULLables properly.
Signed-off-by: Daniel Stone <daniel@fooishbar.org>
Since glibc dlsym() calls calloc, we get a call to our calloc wrapper as
we try to look up the real calloc implementation. dlsym() will fall back
to a static buffer in case calloc returns NULL, so that's what we'll do.
This is all highly glibc dependent, of course, but the entire malloc
weak symbol wrapper mechanism is, so there's no loss of generality here.
So all our tests don't start failing just because we had the temerity to
use realloc() rather than malloc().
Signed-off-by: Daniel Stone <daniel@fooishbar.org>
