h3/proto/
stream.rs

1use bytes::{Buf, BufMut};
2use std::{
3    convert::TryFrom,
4    fmt::{self, Display},
5    ops::Add,
6};
7
8use crate::webtransport::SessionId;
9
10use super::{
11    coding::{BufExt, BufMutExt, Decode, Encode, UnexpectedEnd},
12    varint::VarInt,
13};
14
15#[derive(Debug, PartialEq, Eq, Clone)]
16pub struct StreamType(u64);
17
18macro_rules! stream_types {
19    {$($name:ident = $val:expr,)*} => {
20        impl StreamType {
21            $(pub const $name: StreamType = StreamType($val);)*
22        }
23    }
24}
25
26stream_types! {
27    CONTROL = 0x00,
28    PUSH = 0x01,
29    ENCODER = 0x02,
30    DECODER = 0x03,
31    WEBTRANSPORT_BIDI = 0x41,
32    WEBTRANSPORT_UNI = 0x54,
33}
34
35impl StreamType {
36    pub const MAX_ENCODED_SIZE: usize = VarInt::MAX_SIZE;
37
38    pub fn value(&self) -> u64 {
39        self.0
40    }
41    /// returns a StreamType type with random number of the 0x1f * N + 0x21
42    /// format within the range of the Varint implementation
43    pub fn grease() -> Self {
44        StreamType(fastrand::u64(0..0x210842108421083) * 0x1f + 0x21)
45    }
46}
47
48impl Decode for StreamType {
49    fn decode<B: Buf>(buf: &mut B) -> Result<Self, UnexpectedEnd> {
50        Ok(StreamType(buf.get_var()?))
51    }
52}
53
54impl Encode for StreamType {
55    fn encode<W: BufMut>(&self, buf: &mut W) {
56        buf.write_var(self.0);
57    }
58}
59
60impl fmt::Display for StreamType {
61    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
62        match self {
63            &StreamType::CONTROL => write!(f, "Control"),
64            &StreamType::ENCODER => write!(f, "Encoder"),
65            &StreamType::DECODER => write!(f, "Decoder"),
66            &StreamType::WEBTRANSPORT_UNI => write!(f, "WebTransportUni"),
67            x => write!(f, "StreamType({})", x.0),
68        }
69    }
70}
71
72/// Identifier for a stream
73#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
74pub struct StreamId(#[cfg(not(test))] u64, #[cfg(test)] pub(crate) u64);
75
76impl fmt::Display for StreamId {
77    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
78        let initiator = match self.initiator() {
79            Side::Client => "client",
80            Side::Server => "server",
81        };
82        let dir = match self.dir() {
83            Dir::Uni => "uni",
84            Dir::Bi => "bi",
85        };
86        write!(
87            f,
88            "{} {}directional stream {}",
89            initiator,
90            dir,
91            self.index()
92        )
93    }
94}
95
96impl StreamId {
97    pub(crate) const FIRST_REQUEST: Self = Self::new(0, Dir::Bi, Side::Client);
98
99    /// Is this a client-initiated request?
100    pub fn is_request(&self) -> bool {
101        self.dir() == Dir::Bi && self.initiator() == Side::Client
102    }
103
104    /// Is this a server push?
105    pub fn is_push(&self) -> bool {
106        self.dir() == Dir::Uni && self.initiator() == Side::Server
107    }
108
109    /// Which side of a connection initiated the stream
110    pub(crate) fn initiator(self) -> Side {
111        if self.0 & 0x1 == 0 {
112            Side::Client
113        } else {
114            Side::Server
115        }
116    }
117
118    /// Create a new StreamId
119    const fn new(index: u64, dir: Dir, initiator: Side) -> Self {
120        StreamId((index) << 2 | (dir as u64) << 1 | initiator as u64)
121    }
122
123    /// Distinguishes streams of the same initiator and directionality
124    pub fn index(self) -> u64 {
125        self.0 >> 2
126    }
127
128    /// Which directions data flows in
129    fn dir(self) -> Dir {
130        if self.0 & 0x2 == 0 {
131            Dir::Bi
132        } else {
133            Dir::Uni
134        }
135    }
136
137    #[allow(missing_docs)]
138    pub fn into_inner(self) -> u64 {
139        self.0
140    }
141}
142
143impl TryFrom<u64> for StreamId {
144    type Error = InvalidStreamId;
145    fn try_from(v: u64) -> Result<Self, Self::Error> {
146        if v > VarInt::MAX.0 {
147            return Err(InvalidStreamId(v));
148        }
149        Ok(Self(v))
150    }
151}
152
153impl From<VarInt> for StreamId {
154    fn from(v: VarInt) -> Self {
155        Self(v.0)
156    }
157}
158
159impl From<StreamId> for VarInt {
160    fn from(v: StreamId) -> Self {
161        Self(v.0)
162    }
163}
164
165/// Invalid StreamId, for example because it's too large
166#[derive(Debug, PartialEq)]
167pub struct InvalidStreamId(pub(crate) u64);
168
169impl Display for InvalidStreamId {
170    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
171        write!(f, "invalid stream id: {:x}", self.0)
172    }
173}
174
175impl Encode for StreamId {
176    fn encode<B: bytes::BufMut>(&self, buf: &mut B) {
177        VarInt::from_u64(self.0).unwrap().encode(buf);
178    }
179}
180
181impl Add<usize> for StreamId {
182    type Output = StreamId;
183
184    #[allow(clippy::suspicious_arithmetic_impl)]
185    fn add(self, rhs: usize) -> Self::Output {
186        let index = u64::min(
187            u64::saturating_add(self.index(), rhs as u64),
188            VarInt::MAX.0 >> 2,
189        );
190        Self::new(index, self.dir(), self.initiator())
191    }
192}
193
194impl From<SessionId> for StreamId {
195    fn from(value: SessionId) -> Self {
196        Self(value.into_inner())
197    }
198}
199
200#[derive(Debug, Copy, Clone, Eq, PartialEq)]
201pub enum Side {
202    /// The initiator of a connection
203    Client = 0,
204    /// The acceptor of a connection
205    Server = 1,
206}
207
208/// Whether a stream communicates data in both directions or only from the initiator
209#[derive(Debug, Copy, Clone, Eq, PartialEq)]
210enum Dir {
211    /// Data flows in both directions
212    Bi = 0,
213    /// Data flows only from the stream's initiator
214    Uni = 1,
215}
h3/proto/stream.rs

h3/proto/
stream.rs
