init

internal/queue/queue.go

@@ -0,0 +1,47 @@
+package queue
+
+import (
+	"context"
+	"sync"
+)
+
+type Queue struct {
+	ch      chan int64
+	mu      sync.Mutex
+	pending map[int64]struct{}
+}
+
+func New(size int) *Queue {
+	return &Queue{ch: make(chan int64, size), pending: make(map[int64]struct{})}
+}
+func (q *Queue) Enqueue(id int64) bool {
+	if id <= 0 {
+		return false
+	}
+	q.mu.Lock()
+	if _, ok := q.pending[id]; ok {
+		q.mu.Unlock()
+		return false
+	}
+	q.pending[id] = struct{}{}
+	q.mu.Unlock()
+	select {
+	case q.ch <- id:
+		return true
+	default:
+		q.mu.Lock()
+		delete(q.pending, id)
+		q.mu.Unlock()
+		return false
+	}
+}
+func (q *Queue) Next(ctx context.Context) (int64, bool) {
+	select {
+	case <-ctx.Done():
+		return 0, false
+	case id := <-q.ch:
+		return id, true
+	}
+}
+func (q *Queue) Done(id int64) { q.mu.Lock(); delete(q.pending, id); q.mu.Unlock() }
+func (q *Queue) Len() int      { return len(q.ch) }