-
-
Notifications
You must be signed in to change notification settings - Fork 1.4k
/
fmt.rs
215 lines (175 loc) · 4.52 KB
/
fmt.rs
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
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
//! This module contains types for I/O functionality.
use std::cell::RefCell;
use std::fmt::{self, Write};
use std::future::Future;
use std::rc::Rc;
use std::task::{Poll, Waker};
use futures::future::{self, MaybeDone};
use futures::stream::{FusedStream, Stream};
use futures::StreamExt;
use pin_project::pin_project;
pub(crate) static DEFAULT_BUF_SIZE: usize = 1024;
enum BufStreamState {
Ready,
Pending(Waker),
Done,
}
struct BufStreamInner {
buf: String,
state: BufStreamState,
}
impl BufStreamInner {
const fn new() -> Self {
Self {
buf: String::new(),
state: BufStreamState::Ready,
}
}
fn wake(&self) {
if let BufStreamState::Pending(ref waker) = self.state {
waker.wake_by_ref();
}
}
fn finish(&mut self) {
self.wake();
self.state = BufStreamState::Done;
}
}
pub(crate) struct BufWriter {
inner: Rc<RefCell<BufStreamInner>>,
capacity: usize,
}
impl BufWriter {
pub fn capacity(&self) -> usize {
self.capacity
}
}
impl Write for BufWriter {
fn write_str(&mut self, s: &str) -> fmt::Result {
if s.is_empty() {
return Ok(());
}
let mut inner = self.inner.borrow_mut();
inner.wake();
if inner.buf.is_empty() {
inner.buf.reserve(self.capacity);
}
inner.buf.write_str(s)
}
fn write_char(&mut self, c: char) -> fmt::Result {
let mut inner = self.inner.borrow_mut();
inner.wake();
if inner.buf.is_empty() {
inner.buf.reserve(self.capacity);
}
inner.buf.write_char(c)
}
fn write_fmt(&mut self, args: fmt::Arguments<'_>) -> fmt::Result {
let mut inner = self.inner.borrow_mut();
if inner.buf.is_empty() {
inner.buf.reserve(self.capacity);
}
inner.buf.write_fmt(args)
}
}
pub(crate) struct BufStream {
inner: Rc<RefCell<BufStreamInner>>,
}
impl BufStream {
pub fn new<C, F>(capacity: usize, f: C) -> (BufStream, impl Future<Output = ()>)
where
C: FnOnce(BufWriter) -> F,
F: Future<Output = ()>,
{
let inner = Rc::new(RefCell::new(BufStreamInner::new()));
let resolver = {
let inner = inner.clone();
let w = {
let inner = inner.clone();
BufWriter { inner, capacity }
};
async move {
f(w).await;
inner.borrow_mut().finish();
}
};
(Self { inner }, resolver)
}
}
impl Stream for BufStream {
type Item = String;
fn poll_next(
self: std::pin::Pin<&mut Self>,
cx: &mut std::task::Context<'_>,
) -> std::task::Poll<Option<Self::Item>> {
let mut inner = self.inner.borrow_mut();
if !inner.buf.is_empty() {
let mut buf = String::new();
std::mem::swap(&mut buf, &mut inner.buf);
return Poll::Ready(Some(buf));
}
if let BufStreamState::Done = inner.state {
return Poll::Ready(None);
}
inner.state = BufStreamState::Pending(cx.waker().clone());
Poll::Pending
}
}
impl FusedStream for BufStream {
fn is_terminated(&self) -> bool {
let inner = self.inner.borrow();
matches!(
(&inner.state, inner.buf.is_empty()),
(BufStreamState::Done, true)
)
}
}
#[pin_project]
pub(crate) struct ResolvedBufStream<F>
where
F: Future<Output = ()>,
{
#[pin]
resolver: MaybeDone<F>,
inner: BufStream,
}
impl<F> ResolvedBufStream<F>
where
F: Future<Output = ()>,
{
pub fn new<C>(capacity: usize, f: C) -> ResolvedBufStream<impl Future<Output = ()>>
where
C: FnOnce(BufWriter) -> F,
F: Future<Output = ()>,
{
let (inner, resolver) = BufStream::new(capacity, f);
ResolvedBufStream {
inner,
resolver: future::maybe_done(resolver),
}
}
}
impl<F> Stream for ResolvedBufStream<F>
where
F: Future<Output = ()>,
{
type Item = String;
#[inline]
fn poll_next(
self: std::pin::Pin<&mut Self>,
cx: &mut std::task::Context<'_>,
) -> std::task::Poll<Option<Self::Item>> {
let this = self.project();
let _ = this.resolver.poll(cx);
this.inner.poll_next_unpin(cx)
}
}
impl<F> FusedStream for ResolvedBufStream<F>
where
F: Future<Output = ()>,
{
#[inline]
fn is_terminated(&self) -> bool {
self.inner.is_terminated()
}
}