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//+private
package sync2
when #config(ODIN_SYNC_RECURSIVE_MUTEX_USE_FUTEX, true) {
_Recursive_Mutex :: struct {
owner: Futex,
recursion: i32,
}
_recursive_mutex_lock :: proc(m: ^Recursive_Mutex) {
tid := Futex(current_thread_id())
for {
prev_owner := atomic_compare_exchange_strong_acquire(&m.impl.owner, tid, 0)
switch prev_owner {
case 0, tid:
m.impl.recursion += 1
// inside the lock
return
}
futex_wait(&m.impl.owner, u32(prev_owner))
}
}
_recursive_mutex_unlock :: proc(m: ^Recursive_Mutex) {
m.impl.recursion -= 1
if m.impl.recursion != 0 {
return
}
atomic_exchange_release(&m.impl.owner, 0)
futex_signal(&m.impl.owner)
// outside the lock
}
_recursive_mutex_try_lock :: proc(m: ^Recursive_Mutex) -> bool {
tid := Futex(current_thread_id())
prev_owner := atomic_compare_exchange_strong_acquire(&m.impl.owner, tid, 0)
switch prev_owner {
case 0, tid:
m.impl.recursion += 1
// inside the lock
return true
}
return false
}
} else {
_Recursive_Mutex :: struct {
owner: int,
recursion: int,
mutex: Mutex,
}
_recursive_mutex_lock :: proc(m: ^Recursive_Mutex) {
tid := current_thread_id()
if tid != m.impl.owner {
mutex_lock(&m.impl.mutex)
}
// inside the lock
m.impl.owner = tid
m.impl.recursion += 1
}
_recursive_mutex_unlock :: proc(m: ^Recursive_Mutex) {
tid := current_thread_id()
assert(tid == m.impl.owner)
m.impl.recursion -= 1
recursion := m.impl.recursion
if recursion == 0 {
m.impl.owner = 0
}
if recursion == 0 {
mutex_unlock(&m.impl.mutex)
}
// outside the lock
}
_recursive_mutex_try_lock :: proc(m: ^Recursive_Mutex) -> bool {
tid := current_thread_id()
if m.impl.owner == tid {
return mutex_try_lock(&m.impl.mutex)
}
if !mutex_try_lock(&m.impl.mutex) {
return false
}
// inside the lock
m.impl.owner = tid
m.impl.recursion += 1
return true
}
}
when ODIN_OS != .Windows {
RW_Mutex_State :: distinct uint
RW_Mutex_State_Half_Width :: size_of(RW_Mutex_State)*8/2
RW_Mutex_State_Is_Writing :: RW_Mutex_State(1)
RW_Mutex_State_Writer :: RW_Mutex_State(1)<<1
RW_Mutex_State_Reader :: RW_Mutex_State(1)<<RW_Mutex_State_Half_Width
RW_Mutex_State_Writer_Mask :: RW_Mutex_State(1<<(RW_Mutex_State_Half_Width-1) - 1) << 1
RW_Mutex_State_Reader_Mask :: RW_Mutex_State(1<<(RW_Mutex_State_Half_Width-1) - 1) << RW_Mutex_State_Half_Width
_RW_Mutex :: struct {
// NOTE(bill): pthread_rwlock_t cannot be used since pthread_rwlock_destroy is required on some platforms
// TODO(bill): Can we determine which platforms exactly?
state: RW_Mutex_State,
mutex: Mutex,
sema: Sema,
}
_rw_mutex_lock :: proc(rw: ^RW_Mutex) {
_ = atomic_add(&rw.impl.state, RW_Mutex_State_Writer)
mutex_lock(&rw.impl.mutex)
state := atomic_or(&rw.impl.state, RW_Mutex_State_Writer)
if state & RW_Mutex_State_Reader_Mask != 0 {
sema_wait(&rw.impl.sema)
}
}
_rw_mutex_unlock :: proc(rw: ^RW_Mutex) {
_ = atomic_and(&rw.impl.state, ~RW_Mutex_State_Is_Writing)
mutex_unlock(&rw.impl.mutex)
}
_rw_mutex_try_lock :: proc(rw: ^RW_Mutex) -> bool {
if mutex_try_lock(&rw.impl.mutex) {
state := atomic_load(&rw.impl.state)
if state & RW_Mutex_State_Reader_Mask == 0 {
_ = atomic_or(&rw.impl.state, RW_Mutex_State_Is_Writing)
return true
}
mutex_unlock(&rw.impl.mutex)
}
return false
}
_rw_mutex_shared_lock :: proc(rw: ^RW_Mutex) {
state := atomic_load(&rw.impl.state)
for state & (RW_Mutex_State_Is_Writing|RW_Mutex_State_Writer_Mask) == 0 {
ok: bool
state, ok = atomic_compare_exchange_weak(&rw.impl.state, state, state + RW_Mutex_State_Reader)
if ok {
return
}
}
mutex_lock(&rw.impl.mutex)
_ = atomic_add(&rw.impl.state, RW_Mutex_State_Reader)
mutex_unlock(&rw.impl.mutex)
}
_rw_mutex_shared_unlock :: proc(rw: ^RW_Mutex) {
state := atomic_sub(&rw.impl.state, RW_Mutex_State_Reader)
if (state & RW_Mutex_State_Reader_Mask == RW_Mutex_State_Reader) &&
(state & RW_Mutex_State_Is_Writing != 0) {
sema_post(&rw.impl.sema)
}
}
_rw_mutex_try_shared_lock :: proc(rw: ^RW_Mutex) -> bool {
state := atomic_load(&rw.impl.state)
if state & (RW_Mutex_State_Is_Writing|RW_Mutex_State_Writer_Mask) == 0 {
_, ok := atomic_compare_exchange_strong(&rw.impl.state, state, state + RW_Mutex_State_Reader)
if ok {
return true
}
}
if mutex_try_lock(&rw.impl.mutex) {
_ = atomic_add(&rw.impl.state, RW_Mutex_State_Reader)
mutex_unlock(&rw.impl.mutex)
return true
}
return false
}
}
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