v/vlib/sync/sync_default.c.v

// 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

#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.
pub struct Mutex {
	mutex C.pthread_mutex_t
}

pub struct RwMutex {
	mutex C.pthread_rwlock_t
}

struct RwMutexAttr {
	attr C.pthread_rwlockattr_t
}

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() {
	C.sem_wait(&sem.sem)
}

pub fn (mut sem Semaphore) try_wait() bool {
	return C.sem_trywait(&sem.sem) == 0
}

pub fn (mut sem Semaphore) timed_wait(timeout time.Duration) bool {
	t_spec := timeout.timespec()
	return C.sem_timedwait(&sem.sem, &t_spec) == 0
}

pub fn (sem Semaphore) destroy() bool {
	return C.sem_destroy(&sem.sem) == 0
}