When events are queued, the associated proxy objects (target proxy and
potentially closure argument proxies) are verified being valid. However,
as any event may destroy some proxy object, validity needs to be
verified again before dispatching. Before this change this was done by
again looking up the object via the display object map, but that did not
work because a delete_id event could be dispatched out-of-order if it
was queued in another queue, causing the object map to either have a new
proxy object with the same id or none at all, had it been destroyed in
an earlier event in the queue.
Instead, make wl_proxy reference counted and increase the reference
counter of every object associated with an event when it is queued. In
wl_proxy_destroy() set a flag saying the proxy has been destroyed by the
application and only free the proxy if the reference counter reaches
zero after decreasing it.
Before dispatching, verify that a proxy object still is valid by
checking that the flag set in wl_proxy_destroy() has not been set. When
dequeuing the event, all associated proxy objects are dereferenced and
free:ed if the reference counter reaches zero. As proxy reference counter
is initiated to 1, when dispatching an event it can never reach zero
without having the destroyed flag set.
Signed-off-by: Jonas Ådahl <jadahl@gmail.com>
The _* namespace and identifiers with double underscore are reserved
by the C standard. That makes __wl_container_of is double plus bad,
so lets just call it wl_container_of.
Exporting unprefixed symbols is a pretty bad idea so don't do that.
Instea of redefining it WL_ARRAY_LENGTH, we just move the define to
our private header. The scanner generates code that uses ARRAY_LENGTH,
but we can just make it count the number elements and emit an integer
constant instead.
We don't have a use case for this and the actual semantics and
synchronization behavior of wl_egl_pixmap were never really well-defined.
It also doesn't provide the cross-process buffer sharing that make
window systems pixmaps useful in other window systems.
Touch grabs allow the compositor to be placed into a mode where touch events
temporarily bypass their default behavior and perform other operations.
Wayland already supports keyboard and pointer grabs, but was lacking
corresponding touch support. The default touch grab handlers here contain the
client event delivery code that was previously called directly in weston.
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
If any callback or helper function fails with a fatal error, we now
set the last_error flag and prevent all further I/O on the wl_display. We
wake up all sleeping event-queues and notify the caller that they
should shutdown wl_display.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
We need access to all event-queues of a single wl_display object. For
instance during connection-errors, we need to be able to wake up all event
queues. Otherwise, they will be stuck waiting for incoming events.
The API user is responsible to keep a wl_display object around until all
event-queues that were created on it are destroyed.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
wl_connection_read() assumes that the caller dispatched all messages
before calling it. wl_buffer_put_iov() does only provide enough room so we
fill the buffer. So the only case when the buffer overflows, is when a
previous read filled up the buffer but we couldn't parse a single message
from it. In this case, the client sent a message bigger than our buffer
and we should return an error and close the connection.
krh: Edited from Davids original patch to just check that the buffer
isn't full before we try reading into it.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
We rely on well-defined unsigned overflow behaviour so let's make the
index fields actually unsigned. Signed ints aren't guaranteed to have the
behavior we want (could be either ones or twos complement).
If we read more FDs than we have room for, we currently leak FDs because
we overwrite previous still pending FDs. Instead, we do now close incoming
FDs if the buffer is full and return EOVERFLOW.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Same problem as we had with close_fds(). We cannot rely on the fds_out
buffer being filled with less than MAX_FDS_OUT file descriptors.
Therefore, write at most MAX_FDS_OUT file-descriptors to the outgoing
buffer.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Same problem as with outgoing FDs. We need to close these on shutdown,
otherwise we leak open file descriptors.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
If we push two messages via wl_connection_write() and both messages
contain more than MAX_FDS_OUT file-descriptors combined, then
wl_connection_flush() will write only MAX_FDS_OUT of them, but close all
pending ones, too.
Furthermore, close_fds() will copy more FDs out of the buffer than it can
hold and cause a buffer overflow. Therefore, we simply pass a maximum
limit to close_fds().
During shutdown, we simply close all available FDs.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
When destroying a wl_connection object, there might still be data in the
queue. We would leak open file-descriptors so we must close them.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
If we cannot increase the array for new entries, we now return 0 instead
of accessing invalid memory.
krh: Edited to return 0 on failure instead. In the initialization path,
we call wl_map_insert_new() to insert NULL at index 0, which also returns
0 but not as an error. Since we do that up front, every other case of
returning 0 is an unambiguous error.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
We might have to perform memory allocations in wl_array_copy(), so catch
out-of-memory errors in wl_array_add() and return -1 before changing any
state.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
A server may asynchronously send errors via wl_display.error() events.
Instead of aborting we now the a "last_error" flag inside of wl_display
objects. The user can retrieve these via wl_display_get_error().
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Add some brief documentation for the public libwayland-client entry
points. This is by no means complete, some functions are still
undocumented and some might need extra information.
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Signed-off-by: Tiago Vignatti <tiago.vignatti@intel.com>
This moves desc as first argument of desc_dump().
Description writing was broken on i586 because desc_dump() used
va_arg() after a vsnprintf() call to find the last argument.
But after calling a function with a va_arg argument, this arguments is
undefined.
To let clients determine whether any events were dispatched, we return
the number of dispatched events. An event source with an event queue
(such as wl_display or an X connection) may queue up event as a result of
processing a different event source (data on a network socket, timerfd etc).
After dispatching data from fd (or just before blocking) we have to check
such event sources, which is what wl_event_source_check() is used for.
A checked event source will have its handler called with mask=0 just
before blocking. If any work is done in any of these handlers, we have
to check all the checked sources again, since the work could have queued up
events in a different source. This is why the event handlers must return
a positive number if events were handled. Which in turn is why we need
the wl_display dispatch functions to return that as well.
If the main thread ends up dispatching a non-main queue, and not in
a wl_display_dispatch() callback, we may queue up main queue events and read
all data from the socket fd. When we get back to the main loop, the
socket fd is no longer readable and nothing will trigger dispatching of
the queued up events.
The new function wl_display_dispatch_pending() will dispatch any pending
events, but not attempt to read from the socket. Clients that integrate
the wayland socket fd into a main loop should call
wl_display_dispatch_pending() and then wl_display_flush()
before going back to blocking in poll(2) or similar mechanism.
We need to queue up events even if a proxy doesn't have an implementation
(listener). In case of server created new objects, the client haven't
had a chance to set the listener when the first events to the new object
come in. So now we always queue up events and discard them at
dispatch time if they don't have a listener at that point.
We can't use the same behaviour in both the client and the server. In the
client this is a wl_proxy pointer in the server it's a pointer to the
uint32_t object id. This doesn't fix the problem, but it's a slightly
more useful default, since we typically use WAYLAND_DEBUG on the client.
The function wl_proxy_create_for_id() would try to acquire the display
lock, but the only call path leading to it would call it with the lock
already acquired.
This patch removes the attempt to acquire the lock and makes the
function static. It was exported before because client had to create
proxy's manually when the server sent a new object id, but since commit
9de9e39f [1] this is no longer necessary.
[1] commit 9de9e39f87
Author: Kristian Høgsberg <krh@bitplanet.net>
Date: Thu Jun 28 22:01:58 2012 -0400
Allocate client proxy automatically for new objects
v2: Change the right function. Previous patch changed wl_proxy_create()
instead of wl_proxy_create_for_id().
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.
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.
