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
use crate::cell::UnsafeCell;
use crate::ptr;
use crate::sync::atomic::{AtomicPtr, Ordering::Relaxed};
use crate::sys::locks::{pthread_mutex, Mutex};
use crate::sys_common::lazy_box::{LazyBox, LazyInit};
use crate::time::Duration;
struct AllocatedCondvar(UnsafeCell<libc::pthread_cond_t>);
pub struct Condvar {
inner: LazyBox<AllocatedCondvar>,
mutex: AtomicPtr<libc::pthread_mutex_t>,
}
const TIMESPEC_MAX: libc::timespec =
libc::timespec { tv_sec: <libc::time_t>::MAX, tv_nsec: 1_000_000_000 - 1 };
fn saturating_cast_to_time_t(value: u64) -> libc::time_t {
if value > <libc::time_t>::MAX as u64 { <libc::time_t>::MAX } else { value as libc::time_t }
}
#[inline]
fn raw(c: &Condvar) -> *mut libc::pthread_cond_t {
c.inner.0.get()
}
unsafe impl Send for AllocatedCondvar {}
unsafe impl Sync for AllocatedCondvar {}
impl LazyInit for AllocatedCondvar {
fn init() -> Box<Self> {
let condvar = Box::new(AllocatedCondvar(UnsafeCell::new(libc::PTHREAD_COND_INITIALIZER)));
cfg_if::cfg_if! {
if #[cfg(any(
target_os = "macos",
target_os = "ios",
target_os = "watchos",
target_os = "l4re",
target_os = "android",
target_os = "redox"
))] {
} else if #[cfg(any(target_os = "espidf", target_os = "horizon"))] {
let r = unsafe { libc::pthread_cond_init(condvar.0.get(), crate::ptr::null()) };
assert_eq!(r, 0);
} else {
use crate::mem::MaybeUninit;
let mut attr = MaybeUninit::<libc::pthread_condattr_t>::uninit();
let r = unsafe { libc::pthread_condattr_init(attr.as_mut_ptr()) };
assert_eq!(r, 0);
let r = unsafe { libc::pthread_condattr_setclock(attr.as_mut_ptr(), libc::CLOCK_MONOTONIC) };
assert_eq!(r, 0);
let r = unsafe { libc::pthread_cond_init(condvar.0.get(), attr.as_ptr()) };
assert_eq!(r, 0);
let r = unsafe { libc::pthread_condattr_destroy(attr.as_mut_ptr()) };
assert_eq!(r, 0);
}
}
condvar
}
}
impl Drop for AllocatedCondvar {
#[inline]
fn drop(&mut self) {
let r = unsafe { libc::pthread_cond_destroy(self.0.get()) };
if cfg!(target_os = "dragonfly") {
debug_assert!(r == 0 || r == libc::EINVAL);
} else {
debug_assert_eq!(r, 0);
}
}
}
impl Condvar {
pub const fn new() -> Condvar {
Condvar { inner: LazyBox::new(), mutex: AtomicPtr::new(ptr::null_mut()) }
}
#[inline]
fn verify(&self, mutex: *mut libc::pthread_mutex_t) {
match self.mutex.compare_exchange(ptr::null_mut(), mutex, Relaxed, Relaxed) {
Ok(_) => {} Err(n) if n == mutex => {} _ => panic!("attempted to use a condition variable with two mutexes"),
}
}
#[inline]
pub fn notify_one(&self) {
let r = unsafe { libc::pthread_cond_signal(raw(self)) };
debug_assert_eq!(r, 0);
}
#[inline]
pub fn notify_all(&self) {
let r = unsafe { libc::pthread_cond_broadcast(raw(self)) };
debug_assert_eq!(r, 0);
}
#[inline]
pub unsafe fn wait(&self, mutex: &Mutex) {
let mutex = pthread_mutex::raw(mutex);
self.verify(mutex);
let r = libc::pthread_cond_wait(raw(self), mutex);
debug_assert_eq!(r, 0);
}
#[cfg(not(any(
target_os = "macos",
target_os = "ios",
target_os = "watchos",
target_os = "android",
target_os = "espidf",
target_os = "horizon"
)))]
pub unsafe fn wait_timeout(&self, mutex: &Mutex, dur: Duration) -> bool {
use crate::mem;
let mutex = pthread_mutex::raw(mutex);
self.verify(mutex);
let mut now: libc::timespec = mem::zeroed();
let r = libc::clock_gettime(libc::CLOCK_MONOTONIC, &mut now);
assert_eq!(r, 0);
let nsec = dur.subsec_nanos() + now.tv_nsec as u32;
let sec = saturating_cast_to_time_t(dur.as_secs())
.checked_add((nsec / 1_000_000_000) as libc::time_t)
.and_then(|s| s.checked_add(now.tv_sec));
let nsec = nsec % 1_000_000_000;
let timeout =
sec.map(|s| libc::timespec { tv_sec: s, tv_nsec: nsec as _ }).unwrap_or(TIMESPEC_MAX);
let r = libc::pthread_cond_timedwait(raw(self), mutex, &timeout);
assert!(r == libc::ETIMEDOUT || r == 0);
r == 0
}
#[cfg(any(
target_os = "macos",
target_os = "ios",
target_os = "watchos",
target_os = "android",
target_os = "espidf",
target_os = "horizon"
))]
pub unsafe fn wait_timeout(&self, mutex: &Mutex, mut dur: Duration) -> bool {
use crate::time::Instant;
let mutex = pthread_mutex::raw(mutex);
self.verify(mutex);
let max_dur = Duration::from_secs(1000 * 365 * 86400);
if dur > max_dur {
dur = max_dur;
}
let mut sys_now = libc::timeval { tv_sec: 0, tv_usec: 0 };
let stable_now = Instant::now();
let r = libc::gettimeofday(&mut sys_now, ptr::null_mut());
assert_eq!(r, 0, "unexpected error: {:?}", crate::io::Error::last_os_error());
let nsec = dur.subsec_nanos() as libc::c_long + (sys_now.tv_usec * 1000) as libc::c_long;
let extra = (nsec / 1_000_000_000) as libc::time_t;
let nsec = nsec % 1_000_000_000;
let seconds = saturating_cast_to_time_t(dur.as_secs());
let timeout = sys_now
.tv_sec
.checked_add(extra)
.and_then(|s| s.checked_add(seconds))
.map(|s| libc::timespec { tv_sec: s, tv_nsec: nsec })
.unwrap_or(TIMESPEC_MAX);
let r = libc::pthread_cond_timedwait(raw(self), mutex, &timeout);
debug_assert!(r == libc::ETIMEDOUT || r == 0);
stable_now.elapsed() < dur
}
}