ssip_client_async/
poll.rs

1// ssip-client -- Speech Dispatcher client in Rust
2// Copyright (c) 2022 Laurent Pelecq
3//
4// Licensed under the Apache License, Version 2.0
5// <LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0> or the MIT
6// license <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
7// option. All files in the project carrying such notice may not be copied,
8// modified, or distributed except according to those terms.
9
10use std::collections::VecDeque;
11use std::io::{Read, Write};
12
13use crate::{
14    client::{Client, Source},
15    types::*,
16};
17
18// Hack to generate the doc. There must be a better way.
19#[cfg(all(not(feature = "async-mio"), doc))]
20mod mio {
21    /// Polls for readiness events on all registered values.
22    ///
23    /// See [`mio::Poll`](https://docs.rs/mio/latest/mio/struct.Poll.html#)
24    pub struct Poll {}
25
26    /// Source identifier.
27    ///
28    /// See [`mio::Token`](https://docs.rs/mio/latest/mio/struct.Token.html#).
29    pub struct Token(pub usize);
30}
31
32const INITIAL_REQUEST_QUEUE_CAPACITY: usize = 4;
33
34/// Client with a queue of requests.
35///
36/// The client can be used with crates like [popol](https://crates.io/crates/popol) or
37/// with [mio](https://crates.io/crates/mio) if feature `async-mio` is enabled.
38///
39/// When the output is ready, a next event can be sent.
40pub struct QueuedClient<S: Read + Write + Source> {
41    client: Client<S>,
42    requests: VecDeque<Request>,
43}
44
45impl<S: Read + Write + Source> QueuedClient<S> {
46    /// New asynchronous client build on top of a synchronous client.
47    pub fn new(client: Client<S>) -> Self {
48        Self {
49            client,
50            requests: VecDeque::with_capacity(INITIAL_REQUEST_QUEUE_CAPACITY),
51        }
52    }
53
54    #[cfg(all(not(feature = "async-mio"), unix))]
55    /// Input source.
56    pub fn input_source(&self) -> &S {
57        self.client.input_source()
58    }
59
60    #[cfg(all(not(feature = "async-mio"), unix))]
61    /// Output source.
62    pub fn output_source(&self) -> &S {
63        self.client.output_source()
64    }
65
66    #[cfg(any(feature = "async-mio", doc))]
67    /// Register client
68    pub fn register(
69        &mut self,
70        poll: &mio::Poll,
71        input_token: mio::Token,
72        output_token: mio::Token,
73    ) -> std::io::Result<()> {
74        self.client.register(poll, input_token, output_token)
75    }
76
77    /// Push a new request in the queue.
78    pub fn push(&mut self, request: Request) {
79        self.requests.push_back(request);
80    }
81
82    /// Pop the last request in the queue.
83    pub fn pop(&mut self) -> Option<Request> {
84        self.requests.pop_back()
85    }
86
87    /// Last request in the queue.
88    pub fn last(&self) -> Option<&Request> {
89        self.requests.back()
90    }
91
92    /// Return true if there is a pending request.
93    pub fn has_next(&self) -> bool {
94        !self.requests.is_empty()
95    }
96
97    /// Write one pending request if any.
98    ///
99    /// Instance of `mio::Poll` generates a writable event only once until the socket returns `WouldBlock`.
100    /// This error is mapped to `ClientError::NotReady`.
101    pub fn send_next(&mut self) -> ClientResult<bool> {
102        if let Some(request) = self.requests.pop_front() {
103            self.client.send(request)?;
104            Ok(true)
105        } else {
106            Ok(false)
107        }
108    }
109
110    /// Receive one response.
111    ///
112    /// Must be called each time a readable event is returned by `mio::Poll`.
113    pub fn receive_next(&mut self) -> ClientResult<Response> {
114        self.client.receive()
115    }
116}
ssip_client_async/poll.rs

ssip_client_async/
poll.rs
