support RTSP-over-HTTP (#433) (#768) (#887)

internal/asyncprocessor/async_processor.go

@@ -0,0 +1,72 @@
+// Package asyncprocessor contains an asynchronous processor.
+package asyncprocessor
+
+import (
+	"context"
+
+	"github.com/bluenviron/gortsplib/v4/pkg/ringbuffer"
+)
+
+// Processor is an asynchronous queue processor
+// that allows to detach the routine that is reading a stream
+// from the routine that is writing a stream.
+type Processor struct {
+	BufferSize int
+	OnError    func(context.Context, error)
+
+	running   bool
+	buffer    *ringbuffer.RingBuffer
+	ctx       context.Context
+	ctxCancel func()
+
+	done chan struct{}
+}
+
+// Initialize initializes the processor.
+func (w *Processor) Initialize() {
+	w.buffer, _ = ringbuffer.New(uint64(w.BufferSize))
+	w.ctx, w.ctxCancel = context.WithCancel(context.Background())
+	w.done = make(chan struct{})
+}
+
+// Close closes the processor.
+func (w *Processor) Close() {
+	w.ctxCancel()
+	w.buffer.Close()
+
+	if w.running {
+		<-w.done
+	}
+}
+
+// Start starts the processor.
+func (w *Processor) Start() {
+	w.running = true
+	go w.run()
+}
+
+func (w *Processor) run() {
+	defer close(w.done)
+
+	err := w.runInner()
+	w.OnError(w.ctx, err)
+}
+
+func (w *Processor) runInner() error {
+	for {
+		tmp, ok := w.buffer.Pull()
+		if !ok {
+			return nil
+		}
+
+		err := tmp.(func() error)()
+		if err != nil {
+			return err
+		}
+	}
+}
+
+// Push pushes data to the queue.
+func (w *Processor) Push(cb func() error) bool {
+	return w.buffer.Push(cb)
+}