Vendor main dependencies.

vendor/github.com/BurntSushi/ty/fun/chan.go

@@ -0,0 +1,84 @@
+package fun
+
+import (
+	"reflect"
+
+	"github.com/BurntSushi/ty"
+)
+
+// AsyncChan has a parametric type:
+//
+//	func AsyncChan(chan A) (send chan<- A, recv <-chan A)
+//
+// AsyncChan provides a channel abstraction without a fixed size buffer.
+// The input should be a pointer to a channel that has a type without a
+// direction, e.g., `new(chan int)`. Two new channels are returned: `send` and
+// `recv`. The caller must send data on the `send` channel and receive data on
+// the `recv` channel.
+//
+// Implementation is inspired by Kyle Lemons' work:
+// https://github.com/kylelemons/iq/blob/master/iq_slice.go
+func AsyncChan(baseChan interface{}) (send, recv interface{}) {
+	chk := ty.Check(
+		new(func(*chan ty.A) (chan ty.A, chan ty.A)),
+		baseChan)
+
+	// We don't care about the baseChan---it is only used to construct
+	// the return types.
+	tsend, trecv := chk.Returns[0], chk.Returns[1]
+
+	buf := make([]reflect.Value, 0, 10)
+	rsend := reflect.MakeChan(tsend, 0)
+	rrecv := reflect.MakeChan(trecv, 0)
+
+	go func() {
+		defer rrecv.Close()
+
+	BUFLOOP:
+		for {
+			if len(buf) == 0 {
+				rv, ok := rsend.Recv()
+				if !ok {
+					break BUFLOOP
+				}
+				buf = append(buf, rv)
+			}
+
+			cases := []reflect.SelectCase{
+				// case v, ok := <-send
+				{
+					Dir:  reflect.SelectRecv,
+					Chan: rsend,
+				},
+				// case recv <- buf[0]
+				{
+					Dir:  reflect.SelectSend,
+					Chan: rrecv,
+					Send: buf[0],
+				},
+			}
+			choice, rval, rok := reflect.Select(cases)
+			switch choice {
+			case 0:
+				// case v, ok := <-send
+				if !rok {
+					break BUFLOOP
+				}
+				buf = append(buf, rval)
+			case 1:
+				// case recv <- buf[0]
+				buf = buf[1:]
+			default:
+				panic("bug")
+			}
+		}
+		for _, rv := range buf {
+			rrecv.Send(rv)
+		}
+	}()
+
+	// Create the directional channel types.
+	tsDir := reflect.ChanOf(reflect.SendDir, tsend.Elem())
+	trDir := reflect.ChanOf(reflect.RecvDir, trecv.Elem())
+	return rsend.Convert(tsDir).Interface(), rrecv.Convert(trDir).Interface()
+}