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53d24713a3
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. |
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| 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.