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// Copyright (c) 2019-2021 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module sync
import time
// There's no additional linking (-lpthread) needed for Android.
// See https://stackoverflow.com/a/31277163/1904615
$if !android {
#flag -lpthread
}
#include <semaphore.h>
[trusted]
fn C.pthread_mutex_init(voidptr, voidptr) int
fn C.pthread_mutex_lock(voidptr) int
fn C.pthread_mutex_unlock(voidptr) int
fn C.pthread_mutex_destroy(voidptr) int
fn C.pthread_rwlockattr_init(voidptr) int
fn C.pthread_rwlockattr_setkind_np(voidptr, int) int
fn C.pthread_rwlockattr_setpshared(voidptr, int) int
fn C.pthread_rwlock_init(voidptr, voidptr) int
fn C.pthread_rwlock_rdlock(voidptr) int
fn C.pthread_rwlock_wrlock(voidptr) int
fn C.pthread_rwlock_unlock(voidptr) int
fn C.sem_init(voidptr, int, u32) int
fn C.sem_post(voidptr) int
fn C.sem_wait(voidptr) int
fn C.sem_trywait(voidptr) int
fn C.sem_timedwait(voidptr, voidptr) int
fn C.sem_destroy(voidptr) int
// [init_with=new_mutex] // TODO: implement support for this struct attribute, and disallow Mutex{} from outside the sync.new_mutex() function.
[heap]
pub struct Mutex {
mutex C.pthread_mutex_t
}
[heap]
pub struct RwMutex {
mutex C.pthread_rwlock_t
}
struct RwMutexAttr {
attr C.pthread_rwlockattr_t
}
[heap]
struct Semaphore {
sem C.sem_t
}
pub fn new_mutex() &Mutex {
mut m := &Mutex{}
m.init()
return m
}
pub fn (mut m Mutex) init() {
C.pthread_mutex_init(&m.mutex, C.NULL)
}
pub fn new_rwmutex() &RwMutex {
mut m := &RwMutex{}
m.init()
return m
}
pub fn (mut m RwMutex) init() {
a := RwMutexAttr{}
C.pthread_rwlockattr_init(&a.attr)
// Give writer priority over readers
C.pthread_rwlockattr_setkind_np(&a.attr, C.PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP)
C.pthread_rwlockattr_setpshared(&a.attr, C.PTHREAD_PROCESS_PRIVATE)
C.pthread_rwlock_init(&m.mutex, &a.attr)
}
// @lock(), for *manual* mutex handling, since `lock` is a keyword
pub fn (mut m Mutex) @lock() {
C.pthread_mutex_lock(&m.mutex)
}
pub fn (mut m Mutex) unlock() {
C.pthread_mutex_unlock(&m.mutex)
}
// RwMutex has separate read- and write locks
pub fn (mut m RwMutex) @rlock() {
C.pthread_rwlock_rdlock(&m.mutex)
}
pub fn (mut m RwMutex) @lock() {
C.pthread_rwlock_wrlock(&m.mutex)
}
// Windows SRWLocks have different function to unlock
// So provide two functions here, too, to have a common interface
pub fn (mut m RwMutex) runlock() {
C.pthread_rwlock_unlock(&m.mutex)
}
pub fn (mut m RwMutex) unlock() {
C.pthread_rwlock_unlock(&m.mutex)
}
[inline]
pub fn new_semaphore() &Semaphore {
return new_semaphore_init(0)
}
pub fn new_semaphore_init(n u32) &Semaphore {
mut sem := &Semaphore{}
sem.init(n)
return sem
}
pub fn (mut sem Semaphore) init(n u32) {
C.sem_init(&sem.sem, 0, n)
}
pub fn (mut sem Semaphore) post() {
C.sem_post(&sem.sem)
}
pub fn (mut sem Semaphore) wait() {
for {
if C.sem_wait(&sem.sem) == 0 {
return
}
e := C.errno
match e {
C.EINTR {
continue // interrupted by signal
}
else {
panic(unsafe { tos_clone(&byte(C.strerror(C.errno))) })
}
}
}
}
// `try_wait()` should return as fast as possible so error handling is only
// done when debugging
pub fn (mut sem Semaphore) try_wait() bool {
$if !debug {
return C.sem_trywait(&sem.sem) == 0
} $else {
if C.sem_trywait(&sem.sem) != 0 {
e := C.errno
match e {
C.EAGAIN {
return false
}
else {
panic(unsafe { tos_clone(&byte(C.strerror(C.errno))) })
}
}
}
return true
}
}
pub fn (mut sem Semaphore) timed_wait(timeout time.Duration) bool {
t_spec := timeout.timespec()
for {
if C.sem_timedwait(&sem.sem, &t_spec) == 0 {
return true
}
e := C.errno
match e {
C.EINTR {
continue // interrupted by signal
}
C.ETIMEDOUT {
break
}
else {
panic(unsafe { tos_clone(&byte(C.strerror(e))) })
}
}
}
return false
}
pub fn (sem Semaphore) destroy() {
res := C.sem_destroy(&sem.sem)
if res == 0 {
return
}
panic(unsafe { tos_clone(&byte(C.strerror(res))) })
}
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