vendor tsgo

tools/tsgo/internal/core/semaphore.go

@@ -0,0 +1,52 @@
+package core
+
+import "context"
+
+type Semaphore interface {
+	Acquire() (release func())
+	TryAcquire(ctx context.Context) (release func(), acquired bool)
+}
+
+var _ Semaphore = UnlimitedSemaphore{}
+
+type UnlimitedSemaphore struct{}
+
+func (s UnlimitedSemaphore) Acquire() (release func()) {
+	return func() {}
+}
+
+func (s UnlimitedSemaphore) TryAcquire(ctx context.Context) (release func(), acquired bool) {
+	return func() {}, true
+}
+
+var _ Semaphore = (*LimitedSemaphore)(nil)
+
+type LimitedSemaphore struct {
+	ch      chan struct{}
+	release func()
+}
+
+func NewLimitedSemaphore(maxConcurrency int) *LimitedSemaphore {
+	if maxConcurrency <= 0 {
+		panic("maxConcurrency must be positive")
+	}
+	s := &LimitedSemaphore{
+		ch: make(chan struct{}, maxConcurrency),
+	}
+	s.release = func() { <-s.ch }
+	return s
+}
+
+func (s *LimitedSemaphore) Acquire() (release func()) {
+	s.ch <- struct{}{}
+	return s.release
+}
+
+func (s *LimitedSemaphore) TryAcquire(ctx context.Context) (release func(), acquired bool) {
+	select {
+	case s.ch <- struct{}{}:
+		return s.release, true
+	case <-ctx.Done():
+		return func() {}, false
+	}
+}