diff options
Diffstat (limited to 'scream/cussyc.go')
| -rw-r--r-- | scream/cussyc.go | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/scream/cussyc.go b/scream/cussyc.go new file mode 100644 index 0000000..6bf156d --- /dev/null +++ b/scream/cussyc.go @@ -0,0 +1,205 @@ +package scream
+
+/*
+
+################################################
+# custom golang.org/x/sync/semaphore package #
+# Under MIT Licence **** Sina_Ghaderi #
+################################################
+
+*/
+
+import (
+ "container/list"
+ "context"
+ "sync"
+)
+
+type waiter struct {
+ n int64
+ ready chan<- struct{} // Closed when semaphore acquired.
+}
+
+// NewWeighted creates a new weighted semaphore with the given
+// maximum combined weight for concurrent access.
+func NewWeighted(n int64) *Weighted {
+ w := &Weighted{size: n}
+ return w
+}
+
+// Weighted provides a way to bound concurrent access to a resource.
+// The callers can request access with a given weight.
+type Weighted struct {
+ size int64
+ cur int64
+ mu sync.Mutex
+ waiters list.List
+}
+
+// Acquire acquires the semaphore with a weight of n, blocking until resources
+// are available or ctx is done. On success, returns nil. On failure, returns
+// ctx.Err() and leaves the semaphore unchanged.
+//
+// If ctx is already done, Acquire may still succeed without blocking.
+func (s *Weighted) Acquire(ctx context.Context, n int64) error {
+ s.mu.Lock()
+ if s.size-s.cur >= n && s.waiters.Len() == 0 {
+ s.cur += n
+ s.mu.Unlock()
+ return nil
+ }
+
+ if n > s.size {
+ // Don't make other Acquire calls block on one that's doomed to fail.
+ s.mu.Unlock()
+ <-ctx.Done()
+ return ctx.Err()
+ }
+
+ ready := make(chan struct{})
+ w := waiter{n: n, ready: ready}
+ elem := s.waiters.PushBack(w)
+ s.mu.Unlock()
+
+ select {
+ case <-ctx.Done():
+ err := ctx.Err()
+ s.mu.Lock()
+ select {
+ case <-ready:
+ // Acquired the semaphore after we were canceled. Rather than trying to
+ // fix up the queue, just pretend we didn't notice the cancelation.
+ err = nil
+ default:
+ isFront := s.waiters.Front() == elem
+ s.waiters.Remove(elem)
+ // If we're at the front and there're extra tokens left, notify other waiters.
+ if isFront && s.size > s.cur {
+ s.notifyWaiters()
+ }
+ }
+ s.mu.Unlock()
+ return err
+
+ case <-ready:
+ return nil
+ }
+}
+
+// TryAcquire acquires the semaphore with a weight of n without blocking.
+// On success, returns true. On failure, returns false and leaves the semaphore unchanged.
+func (s *Weighted) TryAcquire(n int64) bool {
+ s.mu.Lock()
+ success := s.size-s.cur >= n && s.waiters.Len() == 0
+ if success {
+ s.cur += n
+ }
+ s.mu.Unlock()
+ return success
+}
+
+// Release releases the semaphore with a weight of n.
+func (s *Weighted) Release(n int64) {
+ s.mu.Lock()
+ s.cur -= n
+ if s.cur < 0 {
+ s.mu.Unlock()
+ panic("semaphore: released more than held")
+ }
+ s.notifyWaiters()
+ s.mu.Unlock()
+}
+
+func (s *Weighted) notifyWaiters() {
+ for {
+ next := s.waiters.Front()
+ if next == nil {
+ break // No more waiters blocked.
+ }
+
+ w := next.Value.(waiter)
+ if s.size-s.cur < w.n {
+ // Not enough tokens for the next waiter. We could keep going (to try to
+ // find a waiter with a smaller request), but under load that could cause
+ // starvation for large requests; instead, we leave all remaining waiters
+ // blocked.
+ //
+ // Consider a semaphore used as a read-write lock, with N tokens, N
+ // readers, and one writer. Each reader can Acquire(1) to obtain a read
+ // lock. The writer can Acquire(N) to obtain a write lock, excluding all
+ // of the readers. If we allow the readers to jump ahead in the queue,
+ // the writer will starve — there is always one token available for every
+ // reader.
+ break
+ }
+
+ s.cur += w.n
+ s.waiters.Remove(next)
+ close(w.ready)
+ }
+}
+
+// AcquireSnix same as Acquire but with a custom channel to puase runing opration
+// Change By Snix.IR, for orginal package please see golang.org/x/sync/semaphore
+func (s *Weighted) AcquireSnix(ctx context.Context, n int64) (int8, error) {
+ select {
+ // kill the process , return 1 ... notify parents stop button pressed
+ case <-StopChan:
+ return 1, nil
+ // check if we get anything from this pause chan, if not
+ // just continue
+ case <-PauseChan:
+ // trap until get action from application
+ select {
+ // contchan save process from this bog
+ case <-ContChan:
+ case <-StopChan:
+ // kill the process , return 1
+ return 1, nil
+ }
+ default:
+ // do nothing :|
+ }
+ s.mu.Lock()
+ if s.size-s.cur >= n && s.waiters.Len() == 0 {
+ s.cur += n
+ s.mu.Unlock()
+ return 0, nil
+ }
+
+ if n > s.size {
+ // Don't make other Acquire calls block on one that's doomed to fail.
+ s.mu.Unlock()
+ <-ctx.Done()
+ return 0, ctx.Err()
+ }
+
+ ready := make(chan struct{})
+ w := waiter{n: n, ready: ready}
+ elem := s.waiters.PushBack(w)
+ s.mu.Unlock()
+
+ select {
+ case <-ctx.Done():
+ err := ctx.Err()
+ s.mu.Lock()
+ select {
+ case <-ready:
+ // Acquired the semaphore after we were canceled. Rather than trying to
+ // fix up the queue, just pretend we didn't notice the cancelation.
+ err = nil
+ default:
+ isFront := s.waiters.Front() == elem
+ s.waiters.Remove(elem)
+ // If we're at the front and there're extra tokens left, notify other waiters.
+ if isFront && s.size > s.cur {
+ s.notifyWaiters()
+ }
+ }
+ s.mu.Unlock()
+ return 0, err
+
+ case <-ready:
+ return 0, nil
+ }
+}
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