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

// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0

use crate::{
    io::{rx, tx},
    path::{self, MaxMtu},
    time::{Clock, Timestamp},
};
use core::{
    fmt,
    future::Future,
    task::{Context, Poll},
};

pub mod limits;
pub use limits::Limiter;

/// Enumerates endpoint types
#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub enum Type {
    /// The endpoint is a client
    Client,
    /// The endpoint is a server
    Server,
}

impl Type {
    /// Returns true if the given endpoint is a QUIC client
    pub fn is_client(self) -> bool {
        self == Self::Client
    }

    /// Returns true if the given endpoint is a QUIC server
    pub fn is_server(self) -> bool {
        self == Self::Server
    }

    /// Returns the [`Type`] of the peer.
    /// - If called on `Client` this will return `Server`
    /// - If called on `Server` this will return `Client`
    #[must_use]
    pub fn peer_type(self) -> Self {
        match self {
            Self::Client => Self::Server,
            Self::Server => Self::Client,
        }
    }
}

/// Enumerates endpoint locations
#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub enum Location {
    /// The local endpoint
    Local,
    /// The remote endpoint
    Remote,
}

impl fmt::Display for Location {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match self {
            Self::Local => write!(f, "the local endpoint"),
            Self::Remote => write!(f, "the remote endpoint"),
        }
    }
}

impl Location {
    /// Returns true if the given endpoint is local
    pub fn is_local(self) -> bool {
        self == Self::Local
    }

    /// Returns true if the given endpoint is remote
    pub fn is_remote(self) -> bool {
        self == Self::Remote
    }

    /// Returns the [`Location`] of the peer.
    /// - If called on `Local` this will return `Remote`
    /// - If called on `Remote` this will return `Local`
    #[must_use]
    pub fn peer_type(self) -> Self {
        match self {
            Self::Local => Self::Remote,
            Self::Remote => Self::Local,
        }
    }
}

/// The main interface for a QUIC endpoint
pub trait Endpoint: 'static + Send + Sized {
    type PathHandle: path::Handle;
    type Subscriber: crate::event::Subscriber;

    const ENDPOINT_TYPE: Type;

    /// Receives and processes datagrams for the Rx queue
    fn receive<Rx, C>(&mut self, rx: &mut Rx, clock: &C)
    where
        Rx: rx::Queue<Handle = Self::PathHandle>,
        C: Clock;

    /// Transmits outgoing datagrams into the Tx queue
    fn transmit<Tx, C>(&mut self, tx: &mut Tx, clock: &C)
    where
        Tx: tx::Queue<Handle = Self::PathHandle>,
        C: Clock;

    /// Returns a future which polls for application-space wakeups
    ///
    /// When successful, the number of wakeups is returned.
    fn wakeups<'a, C: Clock>(&'a mut self, clock: &'a C) -> Wakeups<'a, Self, C> {
        Wakeups {
            endpoint: self,
            clock,
        }
    }

    /// Polls for any application-space wakeups
    ///
    /// When successful, the number of wakeups is returned.
    fn poll_wakeups<C: Clock>(
        &mut self,
        cx: &mut Context<'_>,
        clock: &C,
    ) -> Poll<Result<usize, CloseError>>;

    /// Returns the latest Timestamp at which `transmit` should be called
    fn timeout(&self) -> Option<Timestamp>;

    /// Sets the largest maximum transmission unit (MTU) that can be sent on a path
    fn set_max_mtu(&mut self, max_mtu: MaxMtu);

    /// Returns the endpoint's event subscriber
    fn subscriber(&mut self) -> &mut Self::Subscriber;
}

/// A future which polls an endpoint for application-space wakeups
pub struct Wakeups<'a, E: Endpoint, C: Clock> {
    endpoint: &'a mut E,
    clock: &'a C,
}

impl<'a, E: Endpoint, C: Clock> Future for Wakeups<'a, E, C> {
    type Output = Result<usize, CloseError>;

    fn poll(mut self: core::pin::Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
        let clock = self.clock;
        self.endpoint.poll_wakeups(cx, clock)
    }
}

/// Indicates the endpoint is no longer processing connections.
#[derive(Clone, Copy, Debug)]
pub struct CloseError;