std: add face up down (close #95)

std/engine/face/base_face.go

@@ -11,9 +11,19 @@ type baseFace struct {
 	local   bool
 	onPkt   func(frame []byte) error
 	onError func(err error) error
+	onUp    func()
+	onDown  func()
 	sendMut sync.Mutex
 }
 
+func newBaseFace(local bool) baseFace {
+	return baseFace{
+		local:  local,
+		onUp:   func() {},
+		onDown: func() {},
+	}
+}
+
 func (f *baseFace) IsRunning() bool {
 	return f.running.Load()
 }
@@ -29,3 +39,37 @@ func (f *baseFace) OnPacket(onPkt func(frame []byte) error) {
 func (f *baseFace) OnError(onError func(err error) error) {
 	f.onError = onError
 }
+
+func (f *baseFace) OnUp(onUp func()) {
+	f.onUp = onUp
+}
+
+func (f *baseFace) OnDown(onDown func()) {
+	f.onDown = onDown
+}
+
+// setStateDown sets the face to down state, and makes the down
+// callback if the face was previously up.
+func (f *baseFace) setStateDown() {
+	if f.running.Swap(false) {
+		if f.onDown != nil {
+			f.onDown()
+		}
+	}
+}
+
+// setStateUp sets the face to up state, and makes the up
+// callback if the face was previously down.
+func (f *baseFace) setStateUp() {
+	if !f.running.Swap(true) {
+		if f.onUp != nil {
+			f.onUp()
+		}
+	}
+}
+
+// setStateClosed sets the face to closed state without
+// making the onDown callback. Returns if the face was running.
+func (f *baseFace) setStateClosed() bool {
+	return f.running.Swap(false)
+}

std/engine/face/dummy_face.go

@@ -13,6 +13,7 @@ type DummyFace struct {
 
 func NewDummyFace() *DummyFace {
 	return &DummyFace{
+		baseFace: newBaseFace(true),
 		sendPkts: make([]enc.Buffer, 0),
 	}
 }

std/engine/face/face.go

@@ -14,10 +14,18 @@ type Face interface {
 	// This function should only be called by engine implementations.
 	OnError(onError func(err error) error)
 
-	// Open starts the face.
+	// Open starts the face and may blocks until it is up.
 	Open() error
 	// Close stops the face.
 	Close() error
 	// Send sends a packet frame to the face.
 	Send(pkt enc.Wire) error
+
+	// OnUp sets the callback for the face going up.
+	// The callback may be called multiple times.
+	OnUp(onUp func())
+	// OnDown sets the callback for the face going down.
+	// The callback may be called multiple times.
+	// The callback will not be called when the face is closed.
+	OnDown(onDown func())
 }

std/engine/face/stream_face.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"io"
 	"net"
+	"os"
 
 	enc "github.com/named-data/ndnd/std/encoding"
 	ndn_io "github.com/named-data/ndnd/std/utils/io"
@@ -18,13 +19,16 @@ type StreamFace struct {
 }
 
 func NewStreamFace(network string, addr string, local bool) *StreamFace {
-	return &StreamFace{
-		baseFace: baseFace{
-			local: local,
-		},
-		network: network,
-		addr:    addr,
+	s := &StreamFace{
+		baseFace: newBaseFace(local),
+		network:  network,
+		addr:     addr,
 	}
+
+	// Quit app by default when stream face fails
+	s.OnDown(func() { os.Exit(106) })
+
+	return s
 }
 
 func (f *StreamFace) String() string {
@@ -36,7 +40,7 @@ func (f *StreamFace) Trait() Face {
 }
 
 func (f *StreamFace) Open() error {
-	if f.running.Load() {
+	if f.IsRunning() {
 		return errors.New("face is already running")
 	}
 
@@ -50,27 +54,24 @@ func (f *StreamFace) Open() error {
 	}
 
 	f.conn = c
-	f.running.Store(true)
-
+	f.setStateUp()
 	go f.receive()
 
 	return nil
 }
 
 func (f *StreamFace) Close() error {
-	if !f.running.Swap(false) {
-		return nil
-	}
-
-	if f.conn != nil {
-		return f.conn.Close()
+	if f.setStateClosed() {
+		if f.conn != nil {
+			return f.conn.Close()
+		}
 	}
 
 	return nil
 }
 
 func (f *StreamFace) Send(pkt enc.Wire) error {
-	if !f.running.Load() {
+	if !f.IsRunning() {
 		return errors.New("face is not running")
 	}
 
@@ -86,14 +87,17 @@ func (f *StreamFace) Send(pkt enc.Wire) error {
 }
 
 func (f *StreamFace) receive() {
+	defer f.setStateDown()
+
 	err := ndn_io.ReadTlvStream(f.conn, func(b []byte) bool {
 		if err := f.onPkt(b); err != nil {
+			f.Close()    // engine error
 			return false // break
 		}
 		return f.IsRunning()
 	}, nil)
 
-	if f.running.Swap(false) {
+	if f.IsRunning() {
 		if err != nil {
 			f.onError(err)
 		} else {

std/engine/face/wasm_sim_face.go

@@ -17,10 +17,8 @@ type WasmSimFace struct {
 
 func NewWasmSimFace() *WasmSimFace {
 	return &WasmSimFace{
-		baseFace: baseFace{
-			local: true,
-		},
-		gosim: js.Null(),
+		baseFace: newBaseFace(true),
+		gosim:    js.Null(),
 	}
 }
 
@@ -32,19 +30,6 @@ func (f *WasmSimFace) Trait() Face {
 	return f
 }
 
-func (f *WasmSimFace) Send(pkt enc.Wire) error {
-	if !f.running.Load() {
-		return errors.New("face is not running")
-	}
-
-	l := pkt.Length()
-	arr := js.Global().Get("Uint8Array").New(int(l))
-	js.CopyBytesToJS(arr, pkt.Join())
-	f.gosim.Call("sendPkt", arr)
-
-	return nil
-}
-
 func (f *WasmSimFace) Open() error {
 	if f.onError == nil || f.onPkt == nil {
 		return errors.New("face callbacks are not set")
@@ -59,21 +44,31 @@ func (f *WasmSimFace) Open() error {
 	f.gosim.Call("setRecvPktCallback", js.FuncOf(f.receive))
 
 	log.Info(f, "Face opened")
-	f.running.Store(true)
+	f.setStateUp()
 
 	return nil
 }
 
 func (f *WasmSimFace) Close() error {
-	if f.gosim.IsNull() {
+	if f.setStateClosed() {
+		f.gosim.Call("setRecvPktCallback", js.FuncOf(func(this js.Value, args []js.Value) any {
+			return nil
+		}))
+		f.gosim = js.Null()
+	}
+
+	return nil
+}
+
+func (f *WasmSimFace) Send(pkt enc.Wire) error {
+	if !f.IsRunning() {
 		return errors.New("face is not running")
 	}
 
-	f.running.Store(false)
-	f.gosim.Call("setRecvPktCallback", js.FuncOf(func(this js.Value, args []js.Value) any {
-		return nil
-	}))
-	f.gosim = js.Null()
+	l := pkt.Length()
+	arr := js.Global().Get("Uint8Array").New(int(l))
+	js.CopyBytesToJS(arr, pkt.Join())
+	f.gosim.Call("sendPkt", arr)
 
 	return nil
 }
@@ -86,10 +81,10 @@ func (f *WasmSimFace) receive(this js.Value, args []js.Value) any {
 
 	buf := make([]byte, pkt.Get("byteLength").Int())
 	js.CopyBytesToGo(buf, pkt)
+
 	err := f.onPkt(buf)
 	if err != nil {
-		f.running.Store(false)
-		log.Error(f, "Unable to handle packet: %+v", err)
+		f.Close()
 	}
 
 	return nil

std/engine/face/wasm_ws_face.go

@@ -26,55 +26,54 @@ func (f *WasmWsFace) Trait() Face {
 
 func NewWasmWsFace(url string, local bool) *WasmWsFace {
 	return &WasmWsFace{
-		baseFace: baseFace{
-			local: local,
-		},
-		url:  url,
-		conn: js.Null(),
+		baseFace: newBaseFace(local),
+		url:      url,
+		conn:     js.Null(),
 	}
 }
 
 func (f *WasmWsFace) Open() error {
+	if f.IsRunning() {
+		return errors.New("face is already running")
+	}
+
 	if f.onError == nil || f.onPkt == nil {
 		return errors.New("face callbacks are not set")
 	}
 
-	if !f.conn.IsNull() {
-		return errors.New("face is already running")
-	}
+	// It seems now Go cannot handle exceptions thrown by JS
+	conn := js.Global().Get("WebSocket").New(f.url)
+	conn.Set("binaryType", "arraybuffer")
 
 	ch := make(chan struct{}, 1)
-	// It seems now Go cannot handle exceptions thrown by JS
-	f.conn = js.Global().Get("WebSocket").New(f.url)
-	f.conn.Set("binaryType", "arraybuffer")
-	f.conn.Call("addEventListener", "open", js.FuncOf(func(this js.Value, args []js.Value) interface{} {
+	conn.Call("addEventListener", "message", js.FuncOf(f.receive))
+	conn.Call("addEventListener", "open", js.FuncOf(func(this js.Value, args []js.Value) interface{} {
 		ch <- struct{}{}
 		close(ch)
 		return nil
 	}))
 
-	f.conn.Call("addEventListener", "message", js.FuncOf(f.receive))
 	log.Info(f, "Waiting for WebSocket connection ...")
 	<-ch
 	log.Info(f, "WebSocket connected")
 
-	f.running.Store(true)
+	f.conn = conn
+	f.setStateUp()
 
 	return nil
 }
 
 func (f *WasmWsFace) Close() error {
-	if f.conn.IsNull() {
-		return errors.New("face is not running")
+	if f.setStateClosed() {
+		f.conn.Call("close")
+		f.conn = js.Null()
 	}
-	f.running.Store(false)
-	f.conn.Call("close")
-	f.conn = js.Null()
+
 	return nil
 }
 
 func (f *WasmWsFace) Send(pkt enc.Wire) error {
-	if !f.running.Load() {
+	if !f.IsRunning() {
 		return errors.New("face is not running")
 	}
 
@@ -99,9 +98,7 @@ func (f *WasmWsFace) receive(this js.Value, args []js.Value) any {
 
 	err := f.onPkt(buf)
 	if err != nil {
-		f.running.Store(false)
-		f.conn.Call("close")
-		f.conn = js.Null()
+		f.Close()
 	}
 
 	return nil