1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856
use std::any::Any;
use std::collections::VecDeque;
use std::convert::Infallible;
use std::marker::PhantomData;
use std::os::unix::io::{AsFd, BorrowedFd, OwnedFd};
use std::sync::{atomic::Ordering, Arc, Condvar, Mutex};
use std::task;
use wayland_backend::{
client::{Backend, ObjectData, ObjectId, ReadEventsGuard, WaylandError},
protocol::{Argument, Message},
};
use crate::{conn::SyncData, Connection, DispatchError, Proxy};
/// A trait for handlers of proxies' events delivered to an [`EventQueue`].
///
/// ## General usage
///
/// You need to implement this trait on your `State` for every type of Wayland object that will be processed
/// by the [`EventQueue`] working with your `State`.
///
/// You can have different implementations of the trait for the same interface but different `UserData` type.
/// This way the events for a given object will be processed by the adequate implementation depending on
/// which `UserData` was assigned to it at creation.
///
/// The way this trait works is that the [`Dispatch::event()`] method will be invoked by the event queue for
/// every event received by an object associated to this event queue. Your implementation can then match on
/// the associated [`Proxy::Event`] enum and do any processing needed with that event.
///
/// In the rare case of an interface with *events* creating new objects (in the core protocol, the only
/// instance of this is the `wl_data_device.data_offer` event), you'll need to implement the
/// [`Dispatch::event_created_child()`] method. See the [`event_created_child!()`] macro
/// for a simple way to do this.
///
/// [`event_created_child!()`]: crate::event_created_child!()
///
/// ## Modularity
///
/// To provide generic handlers for downstream usage, it is possible to make an implementation of the trait
/// that is generic over the last type argument, as illustrated below. Users will then be able to
/// automatically delegate their implementation to yours using the [`delegate_dispatch!()`] macro.
///
/// [`delegate_dispatch!()`]: crate::delegate_dispatch!()
///
/// As a result, when your implementation is instantiated, the last type parameter `State` will be the state
/// struct of the app using your generic implementation. You can put additional trait constraints on it to
/// specify an interface between your module and downstream code, as illustrated in this example:
///
/// ```
/// # // Maintainers: If this example changes, please make sure you also carry those changes over to the delegate_dispatch macro.
/// use wayland_client::{protocol::wl_registry, Dispatch};
///
/// /// The type we want to delegate to
/// struct DelegateToMe;
///
/// /// The user data relevant for your implementation.
/// /// When providing a delegate implementation, it is recommended to use your own type here, even if it is
/// /// just a unit struct: using () would cause a risk of clashing with another such implementation.
/// struct MyUserData;
///
/// // Now a generic implementation of Dispatch, we are generic over the last type argument instead of using
/// // the default State=Self.
/// impl<State> Dispatch<wl_registry::WlRegistry, MyUserData, State> for DelegateToMe
/// where
/// // State is the type which has delegated to this type, so it needs to have an impl of Dispatch itself
/// State: Dispatch<wl_registry::WlRegistry, MyUserData>,
/// // If your delegate type has some internal state, it'll need to access it, and you can
/// // require it by adding custom trait bounds.
/// // In this example, we just require an AsMut implementation
/// State: AsMut<DelegateToMe>,
/// {
/// fn event(
/// state: &mut State,
/// _proxy: &wl_registry::WlRegistry,
/// _event: wl_registry::Event,
/// _udata: &MyUserData,
/// _conn: &wayland_client::Connection,
/// _qhandle: &wayland_client::QueueHandle<State>,
/// ) {
/// // Here the delegate may handle incoming events as it pleases.
///
/// // For example, it retrives its state and does some processing with it
/// let me: &mut DelegateToMe = state.as_mut();
/// // do something with `me` ...
/// # std::mem::drop(me) // use `me` to avoid a warning
/// }
/// }
/// ```
///
/// **Note:** Due to limitations in Rust's trait resolution algorithm, a type providing a generic
/// implementation of [`Dispatch`] cannot be used directly as the dispatching state, as rustc
/// currently fails to understand that it also provides `Dispatch<I, U, Self>` (assuming all other
/// trait bounds are respected as well).
pub trait Dispatch<I, UserData, State = Self>
where
Self: Sized,
I: Proxy,
State: Dispatch<I, UserData, State>,
{
/// Called when an event from the server is processed
///
/// This method contains your logic for processing events, which can vary wildly from an object to the
/// other. You are given as argument:
///
/// - a proxy representing the object that received this event
/// - the event itself as the [`Proxy::Event`] enum (which you'll need to match against)
/// - a reference to the `UserData` that was associated with that object on creation
/// - a reference to the [`Connection`] in case you need to access it
/// - a reference to a [`QueueHandle`] associated with the [`EventQueue`] currently processing events, in
/// case you need to create new objects that you want associated to the same [`EventQueue`].
fn event(
state: &mut State,
proxy: &I,
event: I::Event,
data: &UserData,
conn: &Connection,
qhandle: &QueueHandle<State>,
);
/// Method used to initialize the user-data of objects created by events
///
/// If the interface does not have any such event, you can ignore it. If not, the
/// [`event_created_child!()`] macro is provided for overriding it.
///
/// [`event_created_child!()`]: crate::event_created_child!()
#[cfg_attr(coverage, coverage(off))]
fn event_created_child(opcode: u16, _qhandle: &QueueHandle<State>) -> Arc<dyn ObjectData> {
panic!(
"Missing event_created_child specialization for event opcode {} of {}",
opcode,
I::interface().name
);
}
}
/// Macro used to override [`Dispatch::event_created_child()`]
///
/// Use this macro inside the [`Dispatch`] implementation to override this method, to implement the
/// initialization of the user data for event-created objects. The usage syntax is as follow:
///
/// ```ignore
/// impl Dispatch<WlFoo, FooUserData> for MyState {
/// fn event(
/// &mut self,
/// proxy: &WlFoo,
/// event: FooEvent,
/// data: &FooUserData,
/// connhandle: &mut ConnectionHandle,
/// qhandle: &QueueHandle<MyState>
/// ) {
/// /* ... */
/// }
///
/// event_created_child!(MyState, WlFoo, [
/// // there can be multiple lines if this interface has multiple object-creating event
/// EVT_CREATE_BAR => (WlBar, BarUserData::new()),
/// // ~~~~~~~~~~~~~~ ~~~~~ ~~~~~~~~~~~~~~~~~~
/// // | | |
/// // | | +-- an expression whose evaluation produces the
/// // | | user data value
/// // | +-- the type of the newly created object
/// // +-- the opcode of the event that creates a new object, constants for those are
/// // generated alongside the `WlFoo` type in the `wl_foo` module
/// ]);
/// }
/// ```
#[macro_export]
macro_rules! event_created_child {
// Must match `pat` to allow paths `wl_data_device::EVT_DONE_OPCODE` and expressions `0` to both work.
($(@< $( $lt:tt $( : $clt:tt $(+ $dlt:tt )* )? ),+ >)? $selftype:ty, $iface:ty, [$($opcode:pat => ($child_iface:ty, $child_udata:expr)),* $(,)?]) => {
fn event_created_child(
opcode: u16,
qhandle: &$crate::QueueHandle<$selftype>
) -> std::sync::Arc<dyn $crate::backend::ObjectData> {
match opcode {
$(
$opcode => {
qhandle.make_data::<$child_iface, _>({$child_udata})
},
)*
_ => {
panic!("Missing event_created_child specialization for event opcode {} of {}", opcode, <$iface as $crate::Proxy>::interface().name);
},
}
}
};
}
type QueueCallback<State> = fn(
&Connection,
Message<ObjectId, OwnedFd>,
&mut State,
Arc<dyn ObjectData>,
&QueueHandle<State>,
) -> Result<(), DispatchError>;
struct QueueEvent<State>(QueueCallback<State>, Message<ObjectId, OwnedFd>, Arc<dyn ObjectData>);
impl<State> std::fmt::Debug for QueueEvent<State> {
#[cfg_attr(coverage, coverage(off))]
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_struct("QueueEvent").field("msg", &self.1).finish_non_exhaustive()
}
}
/// An event queue
///
/// This is an abstraction for handling event dispatching, that allows you to ensure
/// access to some common state `&mut State` to your event handlers.
///
/// Event queues are created through [`Connection::new_event_queue()`].
///
/// Upon creation, a wayland object is assigned to an event queue by passing the associated [`QueueHandle`]
/// as argument to the method creating it. All events received by that object will be processed by that event
/// queue, when [`dispatch_pending()`][Self::dispatch_pending()] or
/// [`blocking_dispatch()`][Self::blocking_dispatch()] is invoked.
///
/// ## Usage
///
/// ### Single queue app
///
/// If your app is simple enough that the only source of event to process is the Wayland socket and you only
/// need a single event queue, your main loop can be as simple as this:
///
/// ```rust,no_run
/// use wayland_client::Connection;
///
/// let connection = Connection::connect_to_env().unwrap();
/// let mut event_queue = connection.new_event_queue();
///
/// /*
/// * Here your initial setup
/// */
/// # struct State {
/// # exit: bool
/// # }
/// # let mut state = State { exit: false };
///
/// // And the main loop:
/// while !state.exit {
/// event_queue.blocking_dispatch(&mut state).unwrap();
/// }
/// ```
///
/// The [`blocking_dispatch()`][Self::blocking_dispatch()] call will wait (by putting the thread to sleep)
/// until there are some events from the server that can be processed, and all your actual app logic can be
/// done in the callbacks of the [`Dispatch`] implementations, and in the main `loop` after the
/// [`blocking_dispatch()`][Self::blocking_dispatch()] call.
///
/// ### Multi-thread multi-queue app
///
/// In a case where you app is multithreaded and you want to process events in multiple thread, a simple
/// pattern is to have one [`EventQueue`] per thread processing Wayland events.
///
/// With this pattern, each thread can use [`EventQueue::blocking_dispatch()`]
/// on its own event loop, and everything will "Just Work".
///
/// ### Single-queue guest library
///
/// If your code is some library code that will act on a Wayland connection shared by the main program, it is
/// likely you should not trigger socket reads yourself and instead let the main app take care of it. In this
/// case, to ensure your [`EventQueue`] still makes progress, you should regularly invoke
/// [`EventQueue::dispatch_pending()`] which will process the events that were
/// enqueued in the inner buffer of your [`EventQueue`] by the main app reading the socket.
///
/// ### Integrating the event queue with other sources of events
///
/// If your program needs to monitor other sources of events alongside the Wayland socket using a monitoring
/// system like `epoll`, you can integrate the Wayland socket into this system. This is done with the help
/// of the [`EventQueue::prepare_read()`] method. You event loop will be a bit more
/// explicit:
///
/// ```rust,no_run
/// # use wayland_client::Connection;
/// # let connection = Connection::connect_to_env().unwrap();
/// # let mut event_queue = connection.new_event_queue();
/// # let mut state = ();
///
/// loop {
/// // flush the outgoing buffers to ensure that the server does receive the messages
/// // you've sent
/// event_queue.flush().unwrap();
///
/// // (this step is only relevant if other threads might be reading the socket as well)
/// // make sure you don't have any pending events if the event queue that might have been
/// // enqueued by other threads reading the socket
/// event_queue.dispatch_pending(&mut state).unwrap();
///
/// // This puts in place some internal synchronization to prepare for the fact that
/// // you're going to wait for events on the socket and read them, in case other threads
/// // are doing the same thing
/// let read_guard = event_queue.prepare_read().unwrap();
///
/// /*
/// * At this point you can invoke epoll(..) to wait for readiness on the multiple FD you
/// * are working with, and read_guard.connection_fd() will give you the FD to wait on for
/// * the Wayland connection
/// */
/// # let wayland_socket_ready = true;
///
/// if wayland_socket_ready {
/// // If epoll notified readiness of the Wayland socket, you can now proceed to the read
/// read_guard.read().unwrap();
/// // And now, you must invoke dispatch_pending() to actually process the events
/// event_queue.dispatch_pending(&mut state).unwrap();
/// } else {
/// // otherwise, some of your other FD are ready, but you didn't receive Wayland events,
/// // you can drop the guard to cancel the read preparation
/// std::mem::drop(read_guard);
/// }
///
/// /*
/// * There you process all relevant events from your other event sources
/// */
/// }
/// ```
pub struct EventQueue<State> {
handle: QueueHandle<State>,
conn: Connection,
}
#[derive(Debug)]
pub(crate) struct EventQueueInner<State> {
queue: VecDeque<QueueEvent<State>>,
freeze_count: usize,
waker: Option<task::Waker>,
}
impl<State> EventQueueInner<State> {
pub(crate) fn enqueue_event<I, U>(
&mut self,
msg: Message<ObjectId, OwnedFd>,
odata: Arc<dyn ObjectData>,
) where
State: Dispatch<I, U> + 'static,
U: Send + Sync + 'static,
I: Proxy + 'static,
{
let func = queue_callback::<I, U, State>;
self.queue.push_back(QueueEvent(func, msg, odata));
if self.freeze_count == 0 {
if let Some(waker) = self.waker.take() {
waker.wake();
}
}
}
}
impl<State> std::fmt::Debug for EventQueue<State> {
#[cfg_attr(coverage, coverage(off))]
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_struct("EventQueue").field("handle", &self.handle).finish_non_exhaustive()
}
}
impl<State> AsFd for EventQueue<State> {
/// Provides fd from [`Backend::poll_fd`] for polling.
fn as_fd(&self) -> BorrowedFd<'_> {
self.conn.as_fd()
}
}
impl<State> EventQueue<State> {
pub(crate) fn new(conn: Connection) -> Self {
let inner = Arc::new(Mutex::new(EventQueueInner {
queue: VecDeque::new(),
freeze_count: 0,
waker: None,
}));
Self { handle: QueueHandle { inner }, conn }
}
/// Get a [`QueueHandle`] for this event queue
pub fn handle(&self) -> QueueHandle<State> {
self.handle.clone()
}
/// Dispatch pending events
///
/// Events are accumulated in the event queue internal buffer when the Wayland socket is read using
/// the read APIs on [`Connection`], or when reading is done from an other thread.
/// This method will dispatch all such pending events by sequentially invoking their associated handlers:
/// the [`Dispatch`] implementations on the provided `&mut D`.
///
/// Note: this may block if another thread has frozen the queue.
pub fn dispatch_pending(&mut self, data: &mut State) -> Result<usize, DispatchError> {
Self::dispatching_impl(&self.conn, &self.handle, data)
}
/// Block waiting for events and dispatch them
///
/// This method is similar to [`dispatch_pending()`][Self::dispatch_pending], but if there are no
/// pending events it will also flush the connection and block waiting for the Wayland server to send an
/// event.
///
/// A simple app event loop can consist of invoking this method in a loop.
pub fn blocking_dispatch(&mut self, data: &mut State) -> Result<usize, DispatchError> {
let dispatched = self.dispatch_pending(data)?;
if dispatched > 0 {
return Ok(dispatched);
}
self.conn.flush()?;
if let Some(guard) = self.conn.prepare_read() {
crate::conn::blocking_read(guard)?;
}
self.dispatch_pending(data)
}
/// Synchronous roundtrip
///
/// This function will cause a synchronous round trip with the wayland server. This function will block
/// until all requests in the queue are sent and processed by the server.
///
/// This function may be useful during initial setup of your app. This function may also be useful
/// where you need to guarantee all requests prior to calling this function are completed.
pub fn roundtrip(&mut self, data: &mut State) -> Result<usize, DispatchError> {
let done = Arc::new(SyncData::default());
let display = self.conn.display();
self.conn
.send_request(
&display,
crate::protocol::wl_display::Request::Sync {},
Some(done.clone()),
)
.map_err(|_| WaylandError::Io(rustix::io::Errno::PIPE.into()))?;
let mut dispatched = 0;
while !done.done.load(Ordering::Relaxed) {
dispatched += self.blocking_dispatch(data)?;
}
Ok(dispatched)
}
/// 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 the [`EventQueue`] and [`ReadEventsGuard`] docs for details. Once the events are received,
/// you'll then need to dispatch them from the event queue using
/// [`EventQueue::dispatch_pending()`].
///
/// If this method returns [`None`], you should invoke ['dispatch_pending()`][Self::dispatch_pending]
/// before trying to invoke it again.
///
/// If you don't need to manage multiple event sources, see
/// [`blocking_dispatch()`][Self::blocking_dispatch()] for a simpler mechanism.
///
/// This method is identical to [`Connection::prepare_read()`].
#[must_use]
pub fn prepare_read(&self) -> Option<ReadEventsGuard> {
self.conn.prepare_read()
}
/// Flush pending outgoing events to the server
///
/// This needs to be done regularly to ensure the server receives all your requests.
/// /// This method is identical to [`Connection::flush()`].
pub fn flush(&self) -> Result<(), WaylandError> {
self.conn.flush()
}
fn dispatching_impl(
backend: &Connection,
qhandle: &QueueHandle<State>,
data: &mut State,
) -> Result<usize, DispatchError> {
// This call will most of the time do nothing, but ensure that if the Connection is in guest mode
// from some external connection, only invoking `EventQueue::dispatch_pending()` will be enough to
// process the events assuming the host program already takes care of reading the socket.
//
// We purposefully ignore the possible error, as that would make us early return in a way that might
// lose events, and the potential socket error will be caught in other places anyway.
let mut dispatched = backend.backend.dispatch_inner_queue().unwrap_or_default();
while let Some(QueueEvent(cb, msg, odata)) = Self::try_next(&qhandle.inner) {
cb(backend, msg, data, odata, qhandle)?;
dispatched += 1;
}
Ok(dispatched)
}
fn try_next(inner: &Mutex<EventQueueInner<State>>) -> Option<QueueEvent<State>> {
let mut lock = inner.lock().unwrap();
if lock.freeze_count != 0 && !lock.queue.is_empty() {
let waker = Arc::new(DispatchWaker { cond: Condvar::new() });
while lock.freeze_count != 0 {
lock.waker = Some(waker.clone().into());
lock = waker.cond.wait(lock).unwrap();
}
}
lock.queue.pop_front()
}
/// Attempt to dispatch events from this queue, registering the current task for wakeup if no
/// events are pending.
///
/// This method is similar to [`dispatch_pending()`][Self::dispatch_pending]; it will not
/// perform reads on the Wayland socket. Reads on the socket by other tasks or threads will
/// cause the current task to wake up if events are pending on this queue.
///
/// ```
/// use futures_channel::mpsc::Receiver;
/// use futures_util::future::{poll_fn,select};
/// use futures_util::stream::StreamExt;
/// use wayland_client::EventQueue;
///
/// struct Data;
///
/// enum AppEvent {
/// SomethingHappened(u32),
/// }
///
/// impl Data {
/// fn handle(&mut self, event: AppEvent) {
/// // actual event handling goes here
/// }
/// }
///
/// // An async task that is spawned on an executor in order to handle events that need access
/// // to a specific data object.
/// async fn run(data: &mut Data, mut wl_queue: EventQueue<Data>, mut app_queue: Receiver<AppEvent>)
/// -> Result<(), Box<dyn std::error::Error>>
/// {
/// use futures_util::future::Either;
/// loop {
/// match select(
/// poll_fn(|cx| wl_queue.poll_dispatch_pending(cx, data)),
/// app_queue.next(),
/// ).await {
/// Either::Left((res, _)) => match res? {},
/// Either::Right((Some(event), _)) => {
/// data.handle(event);
/// }
/// Either::Right((None, _)) => return Ok(()),
/// }
/// }
/// }
/// ```
pub fn poll_dispatch_pending(
&mut self,
cx: &mut task::Context,
data: &mut State,
) -> task::Poll<Result<Infallible, DispatchError>> {
loop {
if let Err(e) = self.conn.backend.dispatch_inner_queue() {
return task::Poll::Ready(Err(e.into()));
}
let mut lock = self.handle.inner.lock().unwrap();
if lock.freeze_count != 0 {
lock.waker = Some(cx.waker().clone());
return task::Poll::Pending;
}
let QueueEvent(cb, msg, odata) = if let Some(elt) = lock.queue.pop_front() {
elt
} else {
lock.waker = Some(cx.waker().clone());
return task::Poll::Pending;
};
drop(lock);
cb(&self.conn, msg, data, odata, &self.handle)?
}
}
}
struct DispatchWaker {
cond: Condvar,
}
impl task::Wake for DispatchWaker {
fn wake(self: Arc<Self>) {
self.cond.notify_all()
}
}
/// A handle representing an [`EventQueue`], used to assign objects upon creation.
pub struct QueueHandle<State> {
pub(crate) inner: Arc<Mutex<EventQueueInner<State>>>,
}
/// A handle that temporarily pauses event processing on an [`EventQueue`].
#[derive(Debug)]
pub struct QueueFreezeGuard<'a, State> {
qh: &'a QueueHandle<State>,
}
impl<State> std::fmt::Debug for QueueHandle<State> {
#[cfg_attr(coverage, coverage(off))]
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_struct("QueueHandle").field("inner", &Arc::as_ptr(&self.inner)).finish()
}
}
impl<State> Clone for QueueHandle<State> {
fn clone(&self) -> Self {
Self { inner: self.inner.clone() }
}
}
impl<State: 'static> QueueHandle<State> {
/// Create an object data associated with this event queue
///
/// This creates an implementation of [`ObjectData`] fitting for direct use with `wayland-backend` APIs
/// that forwards all events to the event queue associated with this token, integrating the object into
/// the [`Dispatch`]-based logic of `wayland-client`.
pub fn make_data<I: Proxy + 'static, U: Send + Sync + 'static>(
&self,
user_data: U,
) -> Arc<dyn ObjectData>
where
State: Dispatch<I, U, State>,
{
Arc::new(QueueProxyData::<I, U, State> {
handle: self.clone(),
udata: user_data,
_phantom: PhantomData,
})
}
/// Temporarily block processing on this queue.
///
/// This will cause the associated queue to block (or return `NotReady` to poll) until all
/// [`QueueFreezeGuard`]s associated with the queue are dropped.
pub fn freeze(&self) -> QueueFreezeGuard<State> {
self.inner.lock().unwrap().freeze_count += 1;
QueueFreezeGuard { qh: self }
}
}
impl<'a, State> Drop for QueueFreezeGuard<'a, State> {
fn drop(&mut self) {
let mut lock = self.qh.inner.lock().unwrap();
lock.freeze_count -= 1;
if lock.freeze_count == 0 && !lock.queue.is_empty() {
if let Some(waker) = lock.waker.take() {
waker.wake();
}
}
}
}
fn queue_callback<
I: Proxy + 'static,
U: Send + Sync + 'static,
State: Dispatch<I, U, State> + 'static,
>(
handle: &Connection,
msg: Message<ObjectId, OwnedFd>,
data: &mut State,
odata: Arc<dyn ObjectData>,
qhandle: &QueueHandle<State>,
) -> Result<(), DispatchError> {
let (proxy, event) = I::parse_event(handle, msg)?;
let udata = odata.data_as_any().downcast_ref().expect("Wrong user_data value for object");
<State as Dispatch<I, U, State>>::event(data, &proxy, event, udata, handle, qhandle);
Ok(())
}
/// The [`ObjectData`] implementation used by Wayland proxies, integrating with [`Dispatch`]
pub struct QueueProxyData<I: Proxy, U, State> {
handle: QueueHandle<State>,
/// The user data associated with this object
pub udata: U,
_phantom: PhantomData<fn(&I)>,
}
impl<I: Proxy + 'static, U: Send + Sync + 'static, State> ObjectData for QueueProxyData<I, U, State>
where
State: Dispatch<I, U, State> + 'static,
{
fn event(
self: Arc<Self>,
_: &Backend,
msg: Message<ObjectId, OwnedFd>,
) -> Option<Arc<dyn ObjectData>> {
let new_data = msg
.args
.iter()
.any(|arg| matches!(arg, Argument::NewId(id) if !id.is_null()))
.then(|| State::event_created_child(msg.opcode, &self.handle));
self.handle.inner.lock().unwrap().enqueue_event::<I, U>(msg, self.clone());
new_data
}
fn destroyed(&self, _: ObjectId) {}
fn data_as_any(&self) -> &dyn Any {
&self.udata
}
}
impl<I: Proxy, U: std::fmt::Debug, State> std::fmt::Debug for QueueProxyData<I, U, State> {
#[cfg_attr(coverage, coverage(off))]
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_struct("QueueProxyData").field("udata", &self.udata).finish()
}
}
/*
* Dispatch delegation helpers
*/
/// A helper macro which delegates a set of [`Dispatch`] implementations for proxies to some other type which
/// provides a generic [`Dispatch`] implementation.
///
/// This macro allows more easily delegating smaller parts of the protocol an application may wish to handle
/// in a modular fashion.
///
/// # Usage
///
/// For example, say you want to delegate events for [`WlRegistry`][crate::protocol::wl_registry::WlRegistry]
/// to the struct `DelegateToMe` for the [`Dispatch`] documentatione example.
///
/// ```
/// use wayland_client::{delegate_dispatch, protocol::wl_registry};
/// #
/// # use wayland_client::Dispatch;
/// #
/// # struct DelegateToMe;
/// # struct MyUserData;
/// #
/// # impl<State> Dispatch<wl_registry::WlRegistry, MyUserData, State> for DelegateToMe
/// # where
/// # State: Dispatch<wl_registry::WlRegistry, MyUserData> + AsMut<DelegateToMe>,
/// # {
/// # fn event(
/// # _state: &mut State,
/// # _proxy: &wl_registry::WlRegistry,
/// # _event: wl_registry::Event,
/// # _udata: &MyUserData,
/// # _conn: &wayland_client::Connection,
/// # _qhandle: &wayland_client::QueueHandle<State>,
/// # ) {
/// # }
/// # }
///
/// // ExampleApp is the type events will be dispatched to.
///
/// /// The application state
/// struct ExampleApp {
/// /// The delegate for handling wl_registry events.
/// delegate: DelegateToMe,
/// }
///
/// // Use delegate_dispatch to implement Dispatch<wl_registry::WlRegistry, MyUserData> for ExampleApp
/// delegate_dispatch!(ExampleApp: [wl_registry::WlRegistry: MyUserData] => DelegateToMe);
///
/// // DelegateToMe requires that ExampleApp implements AsMut<DelegateToMe>, so we provide the
/// // trait implementation.
/// impl AsMut<DelegateToMe> for ExampleApp {
/// fn as_mut(&mut self) -> &mut DelegateToMe {
/// &mut self.delegate
/// }
/// }
///
/// // To explain the macro above, you may read it as the following:
/// //
/// // For ExampleApp, delegate WlRegistry to DelegateToMe.
///
/// // Assert ExampleApp can Dispatch events for wl_registry
/// fn assert_is_registry_delegate<T>()
/// where
/// T: Dispatch<wl_registry::WlRegistry, MyUserData>,
/// {
/// }
///
/// assert_is_registry_delegate::<ExampleApp>();
/// ```
#[macro_export]
macro_rules! delegate_dispatch {
($(@< $( $lt:tt $( : $clt:tt $(+ $dlt:tt )* )? ),+ >)? $dispatch_from:ty : [$interface: ty: $udata: ty] => $dispatch_to: ty) => {
impl$(< $( $lt $( : $clt $(+ $dlt )* )? ),+ >)? $crate::Dispatch<$interface, $udata> for $dispatch_from {
fn event(
state: &mut Self,
proxy: &$interface,
event: <$interface as $crate::Proxy>::Event,
data: &$udata,
conn: &$crate::Connection,
qhandle: &$crate::QueueHandle<Self>,
) {
<$dispatch_to as $crate::Dispatch<$interface, $udata, Self>>::event(state, proxy, event, data, conn, qhandle)
}
fn event_created_child(
opcode: u16,
qhandle: &$crate::QueueHandle<Self>
) -> ::std::sync::Arc<dyn $crate::backend::ObjectData> {
<$dispatch_to as $crate::Dispatch<$interface, $udata, Self>>::event_created_child(opcode, qhandle)
}
}
};
}
/// A helper macro which delegates a set of [`Dispatch`] implementations for proxies to a static handler.
///
/// # Usage
///
/// This macro is useful to implement [`Dispatch`] for interfaces where events are unimportant to
/// the current application and can be ignored.
///
/// # Example
///
/// ```
/// use wayland_client::{delegate_noop, protocol::{wl_data_offer, wl_subcompositor}};
///
/// /// The application state
/// struct ExampleApp {
/// // ...
/// }
///
/// // Ignore all events for this interface:
/// delegate_noop!(ExampleApp: ignore wl_data_offer::WlDataOffer);
///
/// // This interface should not emit events:
/// delegate_noop!(ExampleApp: wl_subcompositor::WlSubcompositor);
/// ```
///
/// This last example will execute `unreachable!()` if the interface emits any events.
#[macro_export]
macro_rules! delegate_noop {
($(@< $( $lt:tt $( : $clt:tt $(+ $dlt:tt )* )? ),+ >)? $dispatch_from: ty : $interface: ty) => {
impl$(< $( $lt $( : $clt $(+ $dlt )* )? ),+ >)? $crate::Dispatch<$interface, ()> for $dispatch_from {
fn event(
_: &mut Self,
_: &$interface,
_: <$interface as $crate::Proxy>::Event,
_: &(),
_: &$crate::Connection,
_: &$crate::QueueHandle<Self>,
) {
unreachable!();
}
}
};
($(@< $( $lt:tt $( : $clt:tt $(+ $dlt:tt )* )? ),+ >)? $dispatch_from: ty : ignore $interface: ty) => {
impl$(< $( $lt $( : $clt $(+ $dlt )* )? ),+ >)? $crate::Dispatch<$interface, ()> for $dispatch_from {
fn event(
_: &mut Self,
_: &$interface,
_: <$interface as $crate::Proxy>::Event,
_: &(),
_: &$crate::Connection,
_: &$crate::QueueHandle<Self>,
) {
}
}
};
}