30 lines
853 B
C++
30 lines
853 B
C++
#include "object/semaphore.h"
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#include "scheduler/scheduler.h"
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glcr::RefPtr<Semaphore> Semaphore::Create() {
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return glcr::AdoptPtr<Semaphore>(new Semaphore());
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}
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// FIXME: We almost certainly have some race conditions
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// between this and unlock where we could end up with
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// a thread in the blocked_threads_ queue while noone is holding the lock.
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void Semaphore::Signal() {
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__atomic_fetch_add(&lock_, 0x1, __ATOMIC_SEQ_CST);
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if (blocked_threads_.size() > 0) {
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auto thread = blocked_threads_.PopFront();
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thread->SetState(Thread::RUNNABLE);
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gScheduler->Enqueue(thread);
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}
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}
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void Semaphore::Wait() {
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while (lock_ == 0) {
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auto thread = gScheduler->CurrentThread();
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thread->SetState(Thread::BLOCKED);
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blocked_threads_.PushBack(thread);
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gScheduler->Yield();
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}
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__atomic_fetch_sub(&lock_, 0x1, __ATOMIC_SEQ_CST);
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}
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