189 lines
4.5 KiB
V
189 lines
4.5 KiB
V
// Copyright (c) 2019-2020 Alexander Medvednikov. All rights reserved.
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// Use of this source code is governed by an MIT license
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// that can be found in the LICENSE file.
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module sync
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import time
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#flag -lpthread
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#include <semaphore.h>
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// [init_with=new_mutex] // TODO: implement support for this struct attribute, and disallow Mutex{} from outside the sync.new_mutex() function.
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[ref_only]
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pub struct Mutex {
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mutex C.pthread_mutex_t
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}
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[ref_only]
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pub struct RwMutex {
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mutex C.pthread_rwlock_t
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}
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[ref_only]
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struct RwMutexAttr {
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attr C.pthread_rwlockattr_t
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}
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/* MacOSX has no unnamed semaphores and no `timed_wait()` at all
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so we emulate the behaviour with other devices */
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struct MacOSX_Semaphore {
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mtx C.pthread_mutex_t
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cond C.pthread_cond_t
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mut:
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count int
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}
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[ref_only]
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struct PosixSemaphore {
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sem C.sem_t
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}
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[ref_only]
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struct CondAttr {
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attr C.pthread_condattr_t
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}
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pub struct Semaphore {
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/*
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$if macos {
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sem &MacOSX_Semaphore
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} $else {
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sem &PosixSemaphore
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}
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*/
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sem voidptr // since the above does not work, yet
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}
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pub fn new_mutex() &Mutex {
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m := &Mutex{}
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C.pthread_mutex_init(&m.mutex, C.NULL)
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return m
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}
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pub fn new_rwmutex() &RwMutex {
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m := &RwMutex{}
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a := &RwMutexAttr{}
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C.pthread_rwlockattr_init(&a.attr)
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// Give writer priority over readers
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C.pthread_rwlockattr_setkind_np(&a.attr, C.PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP)
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C.pthread_rwlockattr_setpshared(&a.attr, C.PTHREAD_PROCESS_PRIVATE)
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C.pthread_rwlock_init(&m.mutex, &a.attr)
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return m
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}
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// m_lock(), for *manual* mutex handling, since `lock` is a keyword
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pub fn (mut m Mutex) m_lock() {
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C.pthread_mutex_lock(&m.mutex)
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}
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pub fn (mut m Mutex) unlock() {
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C.pthread_mutex_unlock(&m.mutex)
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}
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// RwMutex has separate read- and write locks
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pub fn (mut m RwMutex) r_lock() {
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C.pthread_rwlock_rdlock(&m.mutex)
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}
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pub fn (mut m RwMutex) w_lock() {
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C.pthread_rwlock_wrlock(&m.mutex)
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}
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// Windows SRWLocks have different function to unlock
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// So provide two functions here, too, to have a common interface
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pub fn (mut m RwMutex) r_unlock() {
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C.pthread_rwlock_unlock(&m.mutex)
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}
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pub fn (mut m RwMutex) w_unlock() {
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C.pthread_rwlock_unlock(&m.mutex)
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}
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pub fn new_semaphore() Semaphore {
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$if macos {
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s := Semaphore{
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sem: &MacOSX_Semaphore{count: 0}
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}
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C.pthread_mutex_init(&&MacOSX_Semaphore(s.sem).mtx, C.NULL)
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a := &CondAttr{}
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C.pthread_condattr_init(&a.attr)
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C.pthread_condattr_setpshared(&a.attr, C.PTHREAD_PROCESS_PRIVATE)
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C.pthread_cond_init(&&MacOSX_Semaphore(s.sem).cond, &a.attr)
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return s
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} $else {
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s := Semaphore{
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sem: &PosixSemaphore{}
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}
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unsafe { C.sem_init(&&PosixSemaphore(s.sem).sem, 0, 0) }
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return s
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}
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}
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pub fn (s Semaphore) post() {
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$if macos {
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C.pthread_mutex_lock(&&MacOSX_Semaphore(s.sem).mtx)
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(&MacOSX_Semaphore(s.sem)).count++
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C.pthread_cond_signal(&&MacOSX_Semaphore(s.sem).cond)
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C.pthread_mutex_unlock(&&MacOSX_Semaphore(s.sem).mtx)
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} $else {
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unsafe { C.sem_post(&&PosixSemaphore(s.sem).sem) }
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}
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}
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pub fn (s Semaphore) wait() {
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$if macos {
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C.pthread_mutex_lock(&&MacOSX_Semaphore(s.sem).mtx)
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for &MacOSX_Semaphore(s.sem).count == 0 {
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C.pthread_cond_wait(&&MacOSX_Semaphore(s.sem).cond, &&MacOSX_Semaphore(s.sem).mtx)
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}
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(&MacOSX_Semaphore(s.sem)).count--
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C.pthread_mutex_unlock(&&MacOSX_Semaphore(s.sem).mtx)
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} $else {
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unsafe { C.sem_wait(&&PosixSemaphore(s.sem).sem) }
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}
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}
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pub fn (s Semaphore) try_wait() bool {
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$if macos {
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t_spec := time.zero_timespec()
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C.pthread_mutex_lock(&&MacOSX_Semaphore(s.sem).mtx)
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for &MacOSX_Semaphore(s.sem).count == 0 {
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res := C.pthread_cond_timedwait(&&MacOSX_Semaphore(s.sem).cond, &&MacOSX_Semaphore(s.sem).mtx, &t_spec)
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if res == C.ETIMEDOUT {
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break
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}
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}
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mut res := false
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if &MacOSX_Semaphore(s.sem).count > 0 { // success
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(&MacOSX_Semaphore(s.sem)).count--
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res = true
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}
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C.pthread_mutex_unlock(&&MacOSX_Semaphore(s.sem).mtx)
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return res
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} $else {
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return unsafe { C.sem_trywait(&&PosixSemaphore(s.sem).sem) == 0 }
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}
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}
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pub fn (s Semaphore) timed_wait(timeout time.Duration) bool {
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t_spec := timeout.timespec()
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$if macos {
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C.pthread_mutex_lock(&&MacOSX_Semaphore(s.sem).mtx)
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for &MacOSX_Semaphore(s.sem).count == 0 {
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res := C.pthread_cond_timedwait(&&MacOSX_Semaphore(s.sem).cond, &&MacOSX_Semaphore(s.sem).mtx, &t_spec)
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if res == C.ETIMEDOUT {
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break
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}
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}
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mut res := false
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if &MacOSX_Semaphore(s.sem).count > 0 { // success
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(&MacOSX_Semaphore(s.sem)).count--
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res = true
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}
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C.pthread_mutex_unlock(&&MacOSX_Semaphore(s.sem).mtx)
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return res
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} $else {
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return unsafe { C.sem_timedwait(&&PosixSemaphore(s.sem).sem, &t_spec) == 0 }
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}
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}
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