update book code

eBook/examples/chapter_14/multiplex_server2.go

@@ -0,0 +1,58 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+package main
+
+import "fmt"
+
+type Request struct {
+	a, b   int
+	replyc chan int // reply channel inside the Request
+}
+
+type binOp func(a, b int) int
+
+func run(op binOp, req *Request) {
+	req.replyc <- op(req.a, req.b)
+}
+
+func server(op binOp, service chan *Request, quit chan bool) {
+	for {
+		select {
+			case req := <-service:
+				go run(op, req) 
+			case <-quit:
+				return
+		}
+	}
+}
+
+func startServer(op binOp) (service chan *Request, quit chan bool) {
+	service = make(chan *Request)
+	quit = make(chan bool)
+	go server(op, service, quit)
+	return service, quit
+}
+
+func main() {
+	adder, quit := startServer(func(a, b int) int { return a + b })
+	const N = 100
+	var reqs [N]Request
+	for i := 0; i < N; i++ {
+		req := &reqs[i]
+		req.a = i
+		req.b = i + N
+		req.replyc = make(chan int)
+		adder <- req
+	}
+	// checks:
+	for i := N - 1; i >= 0; i-- { // doesn't matter what order
+		if <-reqs[i].replyc != N+2*i {
+			fmt.Println("fail at", i)
+		} else {
+			fmt.Println("Request ", i, " is ok!")
+		}
+	}
+	quit <- true
+	fmt.Println("done")
+}