io_webdav/
coroutine.rs

1//! Generator-shape coroutine driver. Mirrors `core::ops::Coroutine`: a `Yield`
2//! associated type for intermediate progress, a `Return` for terminal output,
3//! and a two-variant [`WebdavCoroutineState`].
4//!
5//! Most coroutines pick the standard [`WebdavYield`] (I/O-only); redirect-aware
6//! ones declare their own (e.g. [`WebdavRedirectYield`]).
7//!
8//! [`WebdavRedirectYield`]: crate::rfc4918::coroutine::WebdavRedirectYield
9
10use alloc::vec::Vec;
11
12/// State yielded by a [`WebdavCoroutine::resume`] step.
13#[derive(Debug)]
14pub enum WebdavCoroutineState<Y, R> {
15    /// Intermediate yield: the driver reacts and resumes.
16    Yielded(Y),
17    /// Terminal yield. By convention `R = Result<Output, Error>`.
18    Complete(R),
19}
20
21/// Standard-shape WebDAV coroutine.
22pub trait WebdavCoroutine {
23    /// Intermediate value handed back on every step.
24    type Yield;
25    /// Terminal value. By convention `Result<Output, Error>`.
26    type Return;
27
28    /// Advances the coroutine one step.
29    ///
30    /// Pass [`None`] on the initial call or after a
31    /// [`WebdavYield::WantsWrite`]. Pass `Some(data)` after a
32    /// [`WebdavYield::WantsRead`]; `Some(&[])` signals EOF.
33    fn resume(&mut self, arg: Option<&[u8]>) -> WebdavCoroutineState<Self::Yield, Self::Return>;
34}
35
36/// Standard I/O-only Yield for coroutines that only read/write socket bytes.
37#[derive(Debug)]
38pub enum WebdavYield {
39    /// Driver should read more bytes and feed them back on the next resume.
40    WantsRead,
41    /// Driver should write these bytes; the next resume typically takes `None`.
42    WantsWrite(Vec<u8>),
43}
44
45/// Coroutine `?`: forwards `Yielded` (via `Into`), short-circuits on `Err` (via
46/// `Into`), evaluates to the inner `Ok` value.
47#[macro_export]
48macro_rules! webdav_try {
49    ($coroutine:expr, $arg:expr $(,)?) => {
50        match $crate::coroutine::WebdavCoroutine::resume($coroutine, $arg) {
51            $crate::coroutine::WebdavCoroutineState::Yielded(y) => {
52                return $crate::coroutine::WebdavCoroutineState::Yielded(y.into());
53            }
54            $crate::coroutine::WebdavCoroutineState::Complete(Err(err)) => {
55                return $crate::coroutine::WebdavCoroutineState::Complete(Err(err.into()));
56            }
57            $crate::coroutine::WebdavCoroutineState::Complete(Ok(value)) => value,
58        }
59    };
60}
io_webdav/coroutine.rs

io_webdav/
coroutine.rs
