1 files changed, 106 insertions, 0 deletions
diff --git a/pkg/flipcall/flipcall_example_test.go b/pkg/flipcall/flipcall_example_test.go
new file mode 100644
index 000000000..572a1f119
--- /dev/null
+++ b/pkg/flipcall/flipcall_example_test.go
@@ -0,0 +1,106 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package flipcall
+
+import (
+	"bytes"
+	"fmt"
+)
+
+func Example() {
+	const (
+		reqPrefix     = "request "
+		respPrefix    = "response "
+		count         = 3
+		maxMessageLen = len(respPrefix) + 1 // 1 digit
+	)
+
+	pwa, err := NewPacketWindowAllocator()
+	if err != nil {
+		panic(err)
+	}
+	defer pwa.Destroy()
+	pwd, err := pwa.Allocate(PacketWindowLengthForDataCap(uint32(maxMessageLen)))
+	if err != nil {
+		panic(err)
+	}
+	clientEP, err := NewEndpoint(ControlModeFutex, pwd)
+	if err != nil {
+		panic(err)
+	}
+	defer clientEP.Destroy()
+	serverEP, err := NewEndpoint(ControlModeFutex, pwd)
+	if err != nil {
+		panic(err)
+	}
+	defer serverEP.Destroy()
+
+	serverDone := make(chan struct{})
+	go func() {
+		defer func() { serverDone <- struct{}{} }()
+		i := 0
+		var buf bytes.Buffer
+		// wait for first request
+		n, err := serverEP.RecvFirst()
+		if err != nil {
+			return
+		}
+		for {
+			// read request
+			buf.Reset()
+			buf.Write(serverEP.Data()[:n])
+			fmt.Println(buf.String())
+			// write response
+			buf.Reset()
+			fmt.Fprintf(&buf, "%s%d", respPrefix, i)
+			copy(serverEP.Data(), buf.Bytes())
+			// send response and wait for next request
+			n, err = serverEP.SendRecv(uint32(buf.Len()))
+			if err != nil {
+				return
+			}
+			i++
+		}
+	}()
+	defer func() {
+		serverEP.Shutdown()
+		<-serverDone
+	}()
+
+	var buf bytes.Buffer
+	for i := 0; i < count; i++ {
+		// write request
+		buf.Reset()
+		fmt.Fprintf(&buf, "%s%d", reqPrefix, i)
+		copy(clientEP.Data(), buf.Bytes())
+		// send request and wait for response
+		n, err := clientEP.SendRecv(uint32(buf.Len()))
+		if err != nil {
+			panic(err)
+		}
+		// read response
+		buf.Reset()
+		buf.Write(clientEP.Data()[:n])
+		fmt.Println(buf.String())
+	}
+
+	// Output:
+	// request 0
+	// response 0
+	// request 1
+	// response 1
+	// request 2
+	// response 2
+}