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
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
//! Queue implementation for RStream
//!
//! This module provides a concurrent queue with Stream interface for dequeuing
//! and async methods for enqueuing.
use async_stream::stream;
use futures_core::Stream;
use futures_util::StreamExt;
use std::fmt;
use std::sync::Arc;
use tokio::sync::{mpsc, Mutex};
/// Error types for Queue operations
#[derive(Debug, Clone, PartialEq)]
pub enum QueueError {
/// Queue has been closed
Closed,
/// Queue is full (for bounded queues with try_enqueue)
Full,
/// Channel disconnected
Disconnected,
}
impl fmt::Display for QueueError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
QueueError::Closed => write!(f, "Queue is closed"),
QueueError::Full => write!(f, "Queue is full"),
QueueError::Disconnected => write!(f, "Queue channel disconnected"),
}
}
}
impl std::error::Error for QueueError {}
/// A Queue represents a concurrent queue with a Stream interface for dequeuing
/// and async methods for enqueuing.
#[derive(Clone)]
pub enum Queue<T> {
Bounded {
sender: Arc<Mutex<Option<mpsc::Sender<T>>>>,
receiver: Arc<Mutex<Option<mpsc::Receiver<T>>>>,
capacity: usize,
},
Unbounded {
sender: Arc<Mutex<Option<mpsc::UnboundedSender<T>>>>,
receiver: Arc<Mutex<Option<mpsc::UnboundedReceiver<T>>>>,
},
}
impl<T> Queue<T>
where
T: Send + 'static,
{
/// Create a new bounded queue with the given capacity
pub fn bounded(capacity: usize) -> Self {
let (sender, receiver) = mpsc::channel(capacity);
Queue::Bounded {
sender: Arc::new(Mutex::new(Some(sender))),
receiver: Arc::new(Mutex::new(Some(receiver))),
capacity,
}
}
/// Create a new unbounded queue
pub fn unbounded() -> Self {
let (sender, receiver) = mpsc::unbounded_channel();
Queue::Unbounded {
sender: Arc::new(Mutex::new(Some(sender))),
receiver: Arc::new(Mutex::new(Some(receiver))),
}
}
/// Enqueue an item into the queue
pub async fn enqueue(&self, item: T) -> Result<(), QueueError> {
match self {
Queue::Bounded { sender, .. } => {
let guard = sender.lock().await;
match &*guard {
Some(sender) => {
match sender.send(item).await {
Ok(_) => Ok(()),
Err(_) => Err(QueueError::Disconnected),
}
}
None => Err(QueueError::Closed),
}
}
Queue::Unbounded { sender, .. } => {
let guard = sender.lock().await;
match &*guard {
Some(sender) => {
match sender.send(item) {
Ok(_) => Ok(()),
Err(_) => Err(QueueError::Disconnected),
}
}
None => Err(QueueError::Closed),
}
}
}
}
/// Try to enqueue an item without blocking
pub async fn try_enqueue(&self, item: T) -> Result<(), QueueError> {
match self {
Queue::Bounded { sender, .. } => {
let guard = sender.lock().await;
match &*guard {
Some(sender) => {
match sender.try_send(item) {
Ok(_) => Ok(()),
Err(mpsc::error::TrySendError::Full(_)) => Err(QueueError::Full),
Err(mpsc::error::TrySendError::Closed(_)) => Err(QueueError::Disconnected),
}
}
None => Err(QueueError::Closed),
}
}
Queue::Unbounded { sender, .. } => {
let guard = sender.lock().await;
match &*guard {
Some(sender) => {
match sender.send(item) {
Ok(_) => Ok(()),
Err(_) => Err(QueueError::Disconnected),
}
}
None => Err(QueueError::Closed),
}
}
}
}
/// Get a rs2_stream for dequeuing items
pub fn dequeue(&self) -> impl Stream<Item = T> + Send + 'static {
match self {
Queue::Bounded { receiver, .. } => {
let receiver = Arc::clone(receiver);
stream! {
loop {
let item = {
let mut guard = receiver.lock().await;
if let Some(rx) = &mut *guard {
rx.recv().await
} else {
None
}
};
match item {
Some(item) => yield item,
None => break,
}
}
}.boxed()
}
Queue::Unbounded { receiver, .. } => {
let receiver = Arc::clone(receiver);
stream! {
loop {
let item = {
let mut guard = receiver.lock().await;
if let Some(rx) = &mut *guard {
rx.recv().await
} else {
None
}
};
match item {
Some(item) => yield item,
None => break,
}
}
}.boxed()
}
}
}
/// Close the queue, preventing further enqueues
pub async fn close(&self) {
match self {
Queue::Bounded { sender, .. } => {
let mut guard = sender.lock().await;
*guard = None;
}
Queue::Unbounded { sender, .. } => {
let mut guard = sender.lock().await;
*guard = None;
}
}
}
/// Get the capacity of the queue (None for unbounded)
pub fn capacity(&self) -> Option<usize> {
match self {
Queue::Bounded { capacity, .. } => Some(*capacity),
Queue::Unbounded { .. } => None,
}
}
/// Check if the queue is empty
pub async fn is_empty(&self) -> bool {
self.len().await == 0
}
/// Get the current number of items in the queue
pub async fn len(&self) -> usize {
match self {
Queue::Bounded { receiver, .. } => {
let guard = receiver.lock().await;
if let Some(rx) = &*guard {
rx.len()
} else {
0
}
}
Queue::Unbounded { receiver, .. } => {
let guard = receiver.lock().await;
if let Some(rx) = &*guard {
rx.len()
} else {
0
}
}
}
}
}
impl<T> fmt::Debug for Queue<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Queue::Bounded { capacity, .. } => {
f.debug_struct("Queue::Bounded")
.field("capacity", capacity)
.finish()
}
Queue::Unbounded { .. } => {
f.debug_struct("Queue::Unbounded").finish()
}
}
}
}