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
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
#[cfg(not(feature = "nightly"))]
use core::marker::PhantomData;
use core::{fmt::Debug, mem::ManuallyDrop};
cfg_if::cfg_if! {
if #[cfg(feature = "std")] {
/// A synchronization primitive that can be used to coordinate threads.
///
/// `Lock` is a type that represents a lock, which can be used to ensure that only one thread
/// can access a shared resource at a time.
///
/// # Example
///
/// ```
/// use utils_atomics::{Lock, lock};
///
/// let (lock, lock_sub) = lock();
/// std::thread::spawn(move || {
/// // Do some work with the shared resource
/// lock.wake();
/// });
///
/// // Do some work with the shared resource
/// lock_sub.wait();
/// ```
#[derive(Debug)]
#[repr(transparent)]
pub struct Lock (std::thread::Thread);
/// A helper type used for coordination with the `Lock`.
///
/// `LockSub` is used in conjunction with a `Lock` to provide a way to wait for the lock to be
/// released.
#[derive(Debug)]
pub struct LockSub ((), #[cfg(not(feature = "nightly"))] PhantomData<*mut ()>);
impl Lock {
/// Transforms the `Lock` into a raw mutable pointer.
#[inline]
pub fn into_raw (self) -> *mut () {
static_assertions::assert_eq_align!(Lock, *mut ());
return unsafe { core::mem::transmute(self) }
}
/// Constructs a `Lock` from a raw mutable pointer.
///
/// # Safety
///
/// This function is unsafe because it assumes the provided pointer is valid and points to a
/// `Lock`.
#[inline]
pub unsafe fn from_raw (raw: *mut ()) -> Self {
static_assertions::assert_eq_align!(Lock, *mut ());
return Self(core::mem::transmute(raw))
}
/// Drops the `Lock` without waking up the waiting threads.
/// This method currently leaks memory when the `std` feature is disabled.
#[inline]
pub fn silent_drop (self) {
let mut this = ManuallyDrop::new(self);
unsafe { core::ptr::drop_in_place(&mut this.0) }
}
}
impl LockSub {
/// Blocks the current thread until the associated `Lock` is dropped.
///
/// # Example
///
/// ```
/// use utils_atomics::{Lock, lock};
///
/// let (lock, lock_sub) = lock();
/// std::thread::spawn(move || {
/// // Do some work with the shared resource
/// lock.wake();
/// });
///
/// // Do some work with the shared resource
/// lock_sub.wait();
/// ```
#[allow(clippy::unused_self)]
#[inline]
pub fn wait (self) {
std::thread::park();
}
/// Blocks the current thread for a specified duration or until the associated `Lock` is dropped,
/// whichever comes first.
///
/// # Example
///
/// ```
/// use utils_atomics::{Lock, lock};
/// use core::time::Duration;
/// use std::time::Instant;
///
/// let (lock, lock_sub) = lock();
/// let handle = std::thread::spawn(move || {
/// // Do some work with the shared resource
/// std::thread::sleep(Duration::from_secs(3));
/// lock.wake();
/// });
///
/// let start = Instant::now();
/// lock_sub.wait_timeout(Duration::from_secs(2));
/// assert!(start.elapsed() >= Duration::from_secs(2));
/// handle.join().unwrap();
/// ```
#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
#[allow(clippy::unused_self)]
#[inline]
pub fn wait_timeout (self, dur: core::time::Duration) {
std::thread::park_timeout(dur);
}
}
impl Drop for Lock {
#[inline]
fn drop (&mut self) {
self.0.unpark();
}
}
/// Acquires a `Lock` and its corresponding `LockSub` for coordinating access to a shared resource.
///
/// # Example
///
/// ```
/// use utils_atomics::{Lock, lock};
///
/// let (lock, lock_sub) = lock();
/// std::thread::spawn(move || {
/// // Do some work with the shared resource
/// lock.wake();
/// });
///
/// // Do some work with the shared resource
/// lock_sub.wait();
/// ```
#[inline]
pub fn lock () -> (Lock, LockSub) {
return (Lock(std::thread::current()), LockSub((), #[cfg(not(feature = "nightly"))] PhantomData))
}
} else {
use alloc::sync::Arc;
/// A synchronization primitive that can be used to coordinate threads.
///
/// `Lock` is a type that represents a lock, which can be used to ensure that only one thread
/// can access a shared resource at a time.
///
/// # Example
///
/// ```
/// use utils_atomics::{Lock, lock};
///
/// let (lock, lock_sub) = lock();
/// std::thread::spawn(move || {
/// // Do some work with the shared resource
/// lock.wake();
/// });
///
/// // Do some work with the shared resource
/// lock_sub.wait();
/// ```
#[derive(Debug)]
#[repr(transparent)]
pub struct Lock (alloc::sync::Arc<()>);
/// A helper type used for coordination with the `Lock`.
///
/// `LockSub` is used in conjunction with a `Lock` to provide a way to wait for the lock to be
/// released.
#[derive(Debug)]
pub struct LockSub (alloc::sync::Arc<()>, #[cfg(not(feature = "nightly"))] PhantomData<*mut ()>);
impl Lock {
/// Transforms the `Lock` into a raw mutable pointer.
#[inline]
pub fn into_raw (self) -> *mut () {
let this = ManuallyDrop::new(self);
return unsafe { Arc::into_raw(core::ptr::read(&this.0)).cast_mut() }
}
/// Constructs a `Lock` from a raw mutable pointer.
///
/// # Safety
///
/// This function is unsafe because it assumes the provided pointer is valid and points to a
/// `Lock`.
#[inline]
pub unsafe fn from_raw (raw: *mut ()) -> Self {
return Self(Arc::from_raw(raw.cast_const()))
}
/// Drops the `Lock` without waking up the waiting threads.
/// This method currently leaks memory when the `std` feature is disabled.
#[inline]
pub fn silent_drop (self) {
core::mem::forget(self);
}
}
impl LockSub {
/// Blocks the current thread until the associated `Lock` is dropped.
///
/// # Example
///
/// ```
/// use utils_atomics::{Lock, lock};
///
/// let (lock, lock_sub) = lock();
/// let handle = std::thread::spawn(move || {
/// // Do some work with the shared resource
/// lock.wake();
/// });
///
/// // Do some work with the shared resource
/// lock_sub.wait();
/// handle.join().unwrap();
/// ```
#[inline]
pub fn wait (self) {
let mut this = self.0;
loop {
match alloc::sync::Arc::try_unwrap(this) {
Ok(_) => return,
Err(e) => this = e
}
core::hint::spin_loop()
}
}
}
/// Acquires a `Lock` and its corresponding `LockSub` for coordinating access to a shared resource.
///
/// # Example
///
/// ```
/// use utils_atomics::{Lock, lock};
///
/// let (lock, lock_sub) = lock();
/// std::thread::spawn(move || {
/// // Do some work with the shared resource
/// lock.wake();
/// });
///
/// // Do some work with the shared resource
/// lock_sub.wait();
/// ```
#[inline]
pub fn lock () -> (Lock, LockSub) {
let lock = alloc::sync::Arc::new(());
return (Lock(lock.clone()), LockSub(lock, #[cfg(not(feature = "nightly"))] PhantomData))
}
impl Drop for Lock {
#[inline]
fn drop (&mut self) {}
}
}
}
impl Lock {
/// Wakes up the waiting threads associated with the `Lock`.
///
/// # Example
///
/// ```
/// use utils_atomics::{Lock, lock};
///
/// let (lock, lock_sub) = lock();
/// std::thread::spawn(move || {
/// // Do some work with the shared resource
/// lock.wake();
/// });
///
/// // Do some work with the shared resource
/// lock_sub.wait();
/// ```
#[allow(clippy::unused_self)]
#[inline]
pub fn wake(self) {}
}
cfg_if::cfg_if! {
if #[cfg(feature = "nightly")] {
impl !Send for LockSub {}
} else {
unsafe impl Sync for LockSub {}
}
}