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Core Wayland window system code and protocol
385fe30e8b
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. |
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| cursor | ||
| doc | ||
| m4 | ||
| protocol | ||
| spec | ||
| src | ||
| tests | ||
| .gitignore | ||
| autogen.sh | ||
| configure.ac | ||
| COPYING | ||
| Makefile.am | ||
| README | ||
| TODO | ||
| wayland-scanner.m4.in | ||
| wayland-scanner.mk | ||
What is Wayland
Wayland is a project to define a protocol for a compositor to talk to
its clients as well as a library implementation of the protocol. The
compositor can be a standalone display server running on Linux kernel
modesetting and evdev input devices, an X applications, or a wayland
client itself. The clients can be traditional applications, X servers
(rootless or fullscreen) or other display servers.
The wayland protocol is essentially only about input handling and
buffer management. The compositor receives input events and forwards
them to the relevant client. The clients creates buffers and renders
into them and notifies the compositor when it needs to redraw. The
protocol also handles drag and drop, selections, window management and
other interactions that must go through the compositor. However, the
protocol does not handle rendering, which is one of the features that
makes wayland so simple. All clients are expected to handle rendering
themselves, typically through cairo or OpenGL.
The weston compositor is a reference implementation of a wayland
compositor and the weston repository also includes a few example
clients clients.
Building the wayland libraries is fairly simple, aside from libffi,
they don't have many dependencies:
$ git clone git://anongit.freedesktop.org/wayland/wayland
$ cd wayland
$ ./autogen.sh --prefix=PREFIX
$ make
$ make install
where PREFIX is where you want to install the libraries. See
http://wayland.freedesktop.org for more complete build instructions
for wayland, weston, xwayland and various toolkits.