wayland_bridge/client.rs
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// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
use crate::display::{Display, DISPLAY_SINGLETON_OBJECT_ID};
use crate::object::{MessageReceiver, ObjectLookupError, ObjectMap, ObjectRef, RequestReceiver};
use crate::seat::InputDispatcher;
use crate::xdg_shell::XdgSurface;
use anyhow::{anyhow, Error};
use futures::channel::mpsc;
use futures::prelude::*;
use futures::select;
use std::any::Any;
use std::cell::{Cell, RefCell};
use std::rc::Rc;
use wayland_server_protocol::WlDisplayEvent;
use {fuchsia_async as fasync, fuchsia_trace as ftrace, fuchsia_wayland_core as wl};
type Task = Box<dyn FnMut(&mut Client) -> Result<(), Error> + 'static>;
#[derive(Clone)]
enum ClientChannel {
Local(Rc<RefCell<mpsc::UnboundedReceiver<zx::MessageBuf>>>),
Remote(Rc<fasync::Channel>),
}
impl ClientChannel {
async fn recv_msg(&mut self, buffer: &mut zx::MessageBuf) -> Result<(), Error> {
match self {
ClientChannel::Local(receiver) => {
let buf = receiver
.borrow_mut()
.next()
.await
.ok_or_else(|| anyhow!("Error receiving message."))?;
*buffer = buf;
Ok(())
}
ClientChannel::Remote(chan) => {
chan.recv_msg(buffer).await.map_err(|e| anyhow!("Error receiving message: {:?}", e))
}
}
}
}
/// The state of a single client connection. Each client connection will have
/// have its own zircon channel and its own set of protocol objects. The
/// |Display| is the only piece of global state that is shared between
/// clients.
pub struct Client {
client_channel: ClientChannel,
/// The display for this client.
display: Display,
/// The set of objects for this client.
objects: ObjectMap,
/// An incoming task queue of closures to be invoked on the client. These
/// closures will be invoked with a mutable reference to the `Client`,
/// providing a way for background tasks to access client resources.
tasks: mpsc::UnboundedReceiver<Task>,
/// The sending endpoint for the task channel.
task_queue: TaskQueue,
/// The sending endpoint for protocol events.
event_queue: EventQueue,
/// If `true`, all requests and events will be logged.
protocol_logging: Rc<Cell<bool>>,
/// Decode and dispatch Scenic input events.
pub input_dispatcher: InputDispatcher,
/// XDG surfaces. Last surface created at the back.
pub xdg_surfaces: Vec<ObjectRef<XdgSurface>>,
}
impl Client {
/// Creates a new client.
pub fn new(chan: fasync::Channel, display: Display) -> Self {
let (sender, receiver) = mpsc::unbounded();
let log_flag = Rc::new(Cell::new(false));
let chan = Rc::new(chan);
let event_queue = EventQueue {
chan: EventQueueChannel::Remote(chan.clone()),
log_flag: log_flag.clone(),
next_serial: Rc::new(Cell::new(0)),
};
Client {
display,
client_channel: ClientChannel::Remote(chan),
objects: ObjectMap::new(),
tasks: receiver,
task_queue: TaskQueue(sender),
protocol_logging: log_flag,
input_dispatcher: InputDispatcher::new(event_queue.clone()),
event_queue,
xdg_surfaces: vec![],
}
}
pub fn new_local(
sender: mpsc::UnboundedSender<zx::MessageBuf>,
receiver: mpsc::UnboundedReceiver<zx::MessageBuf>,
display: Display,
) -> Self {
let (task_sender, tasks) = mpsc::unbounded();
let log_flag = Rc::new(Cell::new(false));
let event_queue = EventQueue {
chan: EventQueueChannel::Local(Rc::new(RefCell::new(sender))),
log_flag: log_flag.clone(),
next_serial: Rc::new(Cell::new(0)),
};
Client {
display,
client_channel: ClientChannel::Local(Rc::new(RefCell::new(receiver))),
objects: ObjectMap::new(),
tasks,
task_queue: TaskQueue(task_sender),
protocol_logging: log_flag,
input_dispatcher: InputDispatcher::new(event_queue.clone()),
event_queue,
xdg_surfaces: vec![],
}
}
/// Enables or disables protocol message logging.
pub fn set_protocol_logging(&mut self, enabled: bool) {
self.protocol_logging.set(enabled);
}
/// Returns `true` if protocol messages should be logged.
pub(crate) fn protocol_logging(&self) -> bool {
self.protocol_logging.get()
}
/// Returns a object that can post messages to the `Client`.
pub fn task_queue(&self) -> TaskQueue {
self.task_queue.clone()
}
/// Returns an object that can post events back to the client.
pub fn event_queue(&self) -> &EventQueue {
&self.event_queue
}
/// Spawns an async task that waits for messages to be received on the
/// zircon channel, decodes the messages, and dispatches them to the
/// corresponding |MessageReceiver|s.
pub fn start(mut self) {
fasync::Task::local(async move {
let mut buffer = zx::MessageBuf::new();
loop {
select! {
// Fusing: we exit when `recv_msg` fails, so we don't
// need to worry about fast-looping when the channel is
// closed.
message = self.client_channel.recv_msg(&mut buffer).fuse() => {
// We got a new message over the zircon channel.
if let Err(e) = message {
println!("Failed to receive message on the channel: {}", e);
break;
}
// Dispatch the message.
if let Err(e) = self.handle_message(buffer.into()) {
println!("Failed to handle message on the channel: {}", e);
break;
}
buffer = zx::MessageBuf::new();
},
// Fusing: we panic immediately if the task queue ever returns
// `None`, so no need to track state of the channel between
// loop iterations. NOTE: for this to remain true, no other code
// can be given access to mutate `self.tasks`.
task = self.tasks.next() => {
// A new closure has been received.
//
// We unwrap since we retain a reference to the
// sending endpoint of the channel, preventing it
// from closing.
if let Err(e) = self.handle_task(task.expect("Task stream has unexpectedly closed.")) {
println!("Failed to run wayland task: {}", e);
break;
}
},
}
}
// We need to shutdown the client. This includes tearing down
// all views associated with this client.
self.xdg_surfaces.iter().for_each(|surface| {
if let Some(t) = surface.try_get(&self) {
t.shutdown(&self);
}
});
}).detach();
}
/// The `Display` for this client.
pub fn display(&self) -> &Display {
&self.display
}
/// Looks up an object in the map and returns a downcasted reference to
/// the implementation.
pub fn get_object<T: Any>(&self, id: wl::ObjectId) -> Result<&T, ObjectLookupError> {
let result = self.objects.get(id);
#[cfg(feature = "fatal_object_lookup_failures")]
if !result.is_ok() {
panic!("Invalid object: {:?}", id);
}
result
}
/// Looks up an object in the map and returns a downcasted reference to
/// the implementation, if it exists.
pub fn try_get_object<T: Any>(&self, id: wl::ObjectId) -> Option<&T> {
self.objects.get(id).ok()
}
/// Looks up an object in the map and returns a downcasted mutable
/// reference to the implementation.
pub fn get_object_mut<T: Any>(
&mut self,
id: wl::ObjectId,
) -> Result<&mut T, ObjectLookupError> {
let result = self.objects.get_mut(id);
#[cfg(feature = "fatal_object_lookup_failures")]
if !result.is_ok() {
panic!("Invalid object: {:?}", id);
}
result
}
/// Looks up an object in the map and returns a downcasted mutable
/// reference to the implementation, if it exists.
pub fn try_get_object_mut<T: Any>(&mut self, id: wl::ObjectId) -> Option<&mut T> {
self.objects.get_mut(id).ok()
}
/// Adds a new object into the map that will handle messages with the sender
/// set to |id|. When a message is received with the corresponding |id|, the
/// message will be decoded and forwarded to the |RequestReceiver|.
///
/// Returns Err if there is already an object for |id| in this |ObjectMap|.
pub fn add_object<I: wl::Interface + 'static, R: RequestReceiver<I> + 'static>(
&mut self,
id: u32,
receiver: R,
) -> Result<ObjectRef<R>, Error> {
self.objects.add_object(id, receiver)
}
/// Adds an object to the map using the low-level primitives. It's favorable
/// to use instead |add_object| if the wayland interface for the object is
/// statically known.
pub fn add_object_raw(
&mut self,
id: wl::ObjectId,
receiver: Box<dyn MessageReceiver>,
request_spec: &'static wl::MessageGroupSpec,
) -> Result<(), Error> {
self.objects.add_object_raw(id, receiver, request_spec)
}
/// Deletes the object `id` from the local object map and send a notification to the
/// client confirming that `id` can be reused.
pub fn delete_id(&mut self, id: wl::ObjectId) -> Result<(), Error> {
self.objects.delete(id)?;
self.event_queue().post(DISPLAY_SINGLETON_OBJECT_ID, WlDisplayEvent::DeleteId { id })
}
/// Reads the message header to find the target for this message and then
/// forwards the message to the associated |MessageReceiver|.
///
/// Returns Err if no object is associated with the sender field in the
/// message header, or if the objects receiver itself fails.
pub(crate) fn handle_message(&mut self, mut message: wl::Message) -> Result<(), Error> {
ftrace::duration!(c"wayland", c"Client::handle_message");
while !message.is_empty() {
let header = message.read_header()?;
// Lookup the table entry for this object & fail if there is no entry
// found.
let (receiver, spec) = self.objects.lookup_internal(&header)?;
// Decode the argument stream and invoke the |MessageReceiver|.
let args = message.read_args(spec.0)?;
receiver(header.sender, header.opcode, args, self)?;
}
Ok(())
}
fn handle_task(&mut self, mut task: Task) -> Result<(), Error> {
ftrace::duration!(c"wayland", c"Client::handle_task");
task(self)
}
pub fn take_view_provider_request(&mut self) -> bool {
self.display.take_view_provider_requests()
}
}
#[derive(Clone)]
enum EventQueueChannel {
Local(Rc<RefCell<mpsc::UnboundedSender<zx::MessageBuf>>>),
Remote(Rc<fasync::Channel>),
}
impl EventQueueChannel {
fn write(&self, message: wl::Message) -> Result<(), Error> {
ftrace::duration!(c"wayland", c"EventQueue::write_to_chan");
let (bytes, mut handles) = message.take();
match self {
EventQueueChannel::Local(sender) => {
let buf = zx::MessageBuf::new_with(bytes, handles);
sender.borrow_mut().unbounded_send(buf)?;
Ok(())
}
EventQueueChannel::Remote(chan) => chan
.write(&bytes, &mut handles)
.map_err(|e| anyhow!("Error writing to channel {:?}", e)),
}
}
}
/// An `EventQueue` enables protocol events to be sent back to the client.
#[derive(Clone)]
pub struct EventQueue {
chan: EventQueueChannel,
log_flag: Rc<Cell<bool>>,
next_serial: Rc<Cell<u32>>,
}
impl EventQueue {
/// Serializes `event` and writes it to the client channel.
///
/// The 'sender' will be embedded in the message header indicating what
/// protocol object dispatched the event.
pub fn post<E: wl::IntoMessage + std::marker::Send>(
&self,
sender: wl::ObjectId,
event: E,
) -> Result<(), Error>
where
<E as wl::IntoMessage>::Error: std::marker::Send + 'static,
{
ftrace::duration!(c"wayland", c"EventQueue::post");
if self.log_flag.get() {
println!("<-e-- {}", event.log(sender));
}
let message = Self::serialize(sender, event)?;
self.chan.write(message)
}
fn serialize<E: wl::IntoMessage>(sender: wl::ObjectId, event: E) -> Result<wl::Message, Error>
where
<E as wl::IntoMessage>::Error: std::marker::Send + 'static,
{
ftrace::duration!(c"wayland", c"EventQueue::serialize");
Ok(event.into_message(sender).unwrap())
}
/// Returns a monotonically increasing value. Many protocol events rely
/// on an event serial number, which can be obtained with this method.
pub fn next_serial(&self) -> u32 {
let serial = self.next_serial.get();
self.next_serial.set(serial + 1);
serial
}
}
/// A `TaskQueue` enables asynchronous operations to post tasks back to the
/// `Client`.
///
/// Ex:
/// let foo: ObjectRef<Foo> = get_foo_ref();
/// let tasks = client.task_queue();
/// task.post(|client| {
/// let foo = foo.get(client);
/// foo.handle_delayed_operation();
/// });
#[derive(Clone)]
pub struct TaskQueue(mpsc::UnboundedSender<Task>);
impl TaskQueue {
/// Posts the closure to be run as soon as possible.
pub fn post<F>(&self, f: F)
where
F: FnMut(&mut Client) -> Result<(), Error> + 'static,
{
// Failure here means the client is shutting down and we don't want to
// accept any more tasks.
let _result = self.0.unbounded_send(Box::new(f));
}
}