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use std::{
env,
io::ErrorKind,
os::unix::net::UnixStream,
os::unix::prelude::FromRawFd,
path::PathBuf,
sync::{
atomic::{AtomicBool, Ordering},
Arc,
},
};
use wayland_backend::{
client::{Backend, InvalidId, ObjectData, ObjectId, ReadEventsGuard, WaylandError},
protocol::{ObjectInfo, ProtocolError},
};
use nix::{fcntl, Error};
use crate::{protocol::wl_display::WlDisplay, EventQueue, Proxy};
/// The Wayland connection
///
/// This is the main type representing your connection to the Wayland server, though most of the interaction
/// with the protocol are actually done using other types. The two main an simple app as for the
/// [`Connection`] are:
///
/// - Obtaining the initial [`WlDisplay`] through the [`display()`](Connection::display) method.
/// - Creating new [`EventQueue`]s with the [`new_event_queue()`](Connection::new_event_queue) method.
///
/// It can be created through the [`connect_to_env()`](Connection::connect_to_env) method to follow the
/// configuration from the environment (which is what you'll do most of the time), or using the
/// [`from_socket()`](Connection::from_socket) method if you retrieved your connected Wayland socket through
/// other means.
///
/// In case you need to plug yourself into an external Wayland connection that you don't control, you'll
/// likely get access to it as a [`Backend`], in which case you can create a [`Connection`] from it using
/// the [`from_backend`](Connection::from_backend) method.
#[derive(Debug, Clone)]
pub struct Connection {
pub(crate) backend: Backend,
}
impl Connection {
/// Try to connect to the Wayland server following the environment
///
/// This is the standard way to initialize a Wayland connection.
pub fn connect_to_env() -> Result<Self, ConnectError> {
let stream = if let Ok(txt) = env::var("WAYLAND_SOCKET") {
// We should connect to the provided WAYLAND_SOCKET
let fd = txt.parse::<i32>().map_err(|_| ConnectError::InvalidFd)?;
// remove the variable so any child processes don't see it
env::remove_var("WAYLAND_SOCKET");
// set the CLOEXEC flag on this FD
let flags = fcntl::fcntl(fd, fcntl::FcntlArg::F_GETFD);
let result = flags
.map(|f| fcntl::FdFlag::from_bits(f).unwrap() | fcntl::FdFlag::FD_CLOEXEC)
.and_then(|f| fcntl::fcntl(fd, fcntl::FcntlArg::F_SETFD(f)));
match result {
Ok(_) => {
// setting the O_CLOEXEC worked
unsafe { FromRawFd::from_raw_fd(fd) }
}
Err(_) => {
// something went wrong in F_GETFD or F_SETFD
let _ = ::nix::unistd::close(fd);
return Err(ConnectError::InvalidFd);
}
}
} else {
let mut socket_path = env::var_os("XDG_RUNTIME_DIR")
.map(Into::<PathBuf>::into)
.ok_or(ConnectError::NoCompositor)?;
socket_path.push(env::var_os("WAYLAND_DISPLAY").ok_or(ConnectError::NoCompositor)?);
UnixStream::connect(socket_path).map_err(|_| ConnectError::NoCompositor)?
};
let backend = Backend::connect(stream).map_err(|_| ConnectError::NoWaylandLib)?;
Ok(Self { backend })
}
/// Initialize a Wayland connection from an already existing Unix stream
pub fn from_socket(stream: UnixStream) -> Result<Self, ConnectError> {
let backend = Backend::connect(stream).map_err(|_| ConnectError::NoWaylandLib)?;
Ok(Self { backend })
}
/// Get the `WlDisplay` associated with this connection
pub fn display(&self) -> WlDisplay {
let display_id = self.backend.display_id();
Proxy::from_id(self, display_id).unwrap()
}
/// Create a new event queue
pub fn new_event_queue<State>(&self) -> EventQueue<State> {
EventQueue::new(self.clone())
}
/// Wrap an existing [`Backend`] into a [`Connection`]
pub fn from_backend(backend: Backend) -> Self {
Self { backend }
}
/// Get the [`Backend`] underlying this [`Connection`]
pub fn backend(&self) -> Backend {
self.backend.clone()
}
/// Flush pending outgoing events to the server
///
/// This needs to be done regularly to ensure the server receives all your requests, though several
/// dispatching methods do it implicitly (this is stated in their documentation when they do).
pub fn flush(&self) -> Result<(), WaylandError> {
self.backend.flush()
}
/// Start a synchronized read from the socket
///
/// This is needed if you plan to wait on readiness of the Wayland socket using an event loop. See
/// [`ReadEventsGuard`] for details. Once the events are received, you'll then need to dispatch them from
/// their event queues using [`EventQueue::dispatch_pending()`](EventQueue::dispatch_pending).
///
/// If you don't need to manage multiple event sources, see
/// [`blocking_dispatch()`](Connection::blocking_read) for a simpler mechanism. [`EventQueue`] has an
/// identical method for convenience.
pub fn prepare_read(&self) -> Result<ReadEventsGuard, WaylandError> {
self.backend.prepare_read()
}
/// Block until events are received from the server
///
/// This will flush the outgoing socket, and then block until events are received from the
/// server and read them. You'll then need to invoke
/// [`EventQueue::dispatch_pending()`](EventQueue::dispatch_pending) to dispatch them on
/// their respective event queues. Alternatively,
/// [`EventQueue::blocking_dispatch()`](EventQueue::blocking_dispatch) does the same thing as this
/// method but also dispatches the pending messages on the queue it was invoked.
///
/// If you created objects bypassing the event queues with direct [`ObjectData`] callbacks, those
/// callbacks will be invoked (if those objects received any events) before this method returns.
pub fn blocking_read(&self) -> Result<usize, WaylandError> {
blocking_dispatch_impl(self.backend.clone())
}
/// Do a roundtrip to the server
///
/// This method will block until the Wayland server has processed and answered all your
/// preceding requests. This is notably useful during the initial setup of an app, to wait for
/// the initial state from the server.
///
/// See [`EventQueue::roundtrip()`] for a version that includes the dispatching of the event queue.
pub fn roundtrip(&self) -> Result<usize, WaylandError> {
let done = Arc::new(AtomicBool::new(false));
{
let display = self.display();
let cb_done = done.clone();
let sync_data = Arc::new(SyncData { done: cb_done });
self.send_request(
&display,
crate::protocol::wl_display::Request::Sync {},
Some(sync_data),
)
.map_err(|_| WaylandError::Io(Error::EPIPE.into()))?;
}
let mut dispatched = 0;
while !done.load(Ordering::Acquire) {
dispatched += blocking_dispatch_impl(self.backend.clone())?;
}
Ok(dispatched)
}
/// Retrieve the protocol error that occured on the connection if any
///
/// If this method returns `Some`, it means your Wayland connection is already dead.
pub fn protocol_error(&self) -> Option<ProtocolError> {
match dbg!(self.backend.last_error())? {
WaylandError::Protocol(err) => Some(err),
WaylandError::Io(_) => None,
}
}
/// Send a request associated with the provided object
///
/// This is a low-level interface used by the code generated by `wayland-scanner`, you will likely
/// instead use the methods of the types representing each interface, or the [`Proxy::send_request`] and
/// [`Proxy::send_constructor`]
pub fn send_request<I: Proxy>(
&self,
proxy: &I,
request: I::Request,
data: Option<Arc<dyn ObjectData>>,
) -> Result<ObjectId, InvalidId> {
let (msg, child_spec) = proxy.write_request(self, request)?;
self.backend.send_request(msg, data, child_spec)
}
/// Get the protocol information related to given object ID
pub fn object_info(&self, id: ObjectId) -> Result<ObjectInfo, InvalidId> {
self.backend.info(id)
}
/// Get the object data for a given object ID
///
/// This is a low-level interface used by the code generated by `wayland-scanner`, a higher-level
/// interface for manipulating the user-data assocated to [`Dispatch`](crate::Dispatch) implementations
/// is given as [`Proxy::data()`]. Also see [`Proxy::object_data()`].
pub fn get_object_data(&self, id: ObjectId) -> Result<Arc<dyn ObjectData>, InvalidId> {
self.backend.get_data(id)
}
}
pub(crate) fn blocking_dispatch_impl(backend: Backend) -> Result<usize, WaylandError> {
backend.flush()?;
// first, prepare the read
let guard = backend.prepare_read()?;
// there is nothing to dispatch, wait for readiness
loop {
let mut fds = [nix::poll::PollFd::new(
guard.connection_fd(),
nix::poll::PollFlags::POLLIN | nix::poll::PollFlags::POLLERR,
)];
match nix::poll::poll(&mut fds, -1) {
Ok(_) => break,
Err(nix::errno::Errno::EINTR) => continue,
Err(e) => return Err(WaylandError::Io(e.into())),
}
}
// at this point the fd is ready
match guard.read() {
Ok(n) => Ok(n),
// if we are still "wouldblock", that means that there was a dispatch from an other
// thread with the C-based backend, spuriously return 0.
Err(WaylandError::Io(e)) if e.kind() == ErrorKind::WouldBlock => Ok(0),
Err(e) => Err(e),
}
}
/// An error when trying to establish a Wayland connection.
#[derive(thiserror::Error, Debug)]
pub enum ConnectError {
/// The wayland library could not be loaded.
#[error("The wayland library could not be loaded")]
NoWaylandLib,
/// Could not find wayland compositor
#[error("Could not find wayland compositor")]
NoCompositor,
/// `WAYLAND_SOCKET` was set but contained garbage
#[error("WAYLAND_SOCKET was set but contained garbage")]
InvalidFd,
}
/*
wl_callback object data for wl_display.sync
*/
pub(crate) struct SyncData {
pub(crate) done: Arc<AtomicBool>,
}
impl ObjectData for SyncData {
fn event(
self: Arc<Self>,
_handle: &Backend,
_msg: wayland_backend::protocol::Message<ObjectId>,
) -> Option<Arc<dyn ObjectData>> {
self.done.store(true, Ordering::Release);
None
}
fn destroyed(&self, _: ObjectId) {}
}