Source file doc/progs/server.go

// 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
}

type binOp func(a, b int) int

func run(op binOp, req *request) {
    reply := op(req.a, req.b)
    req.replyc <- reply
}

func server(op binOp, service chan *request) {
    for {
        req := <-service
        go run(op, req) // don't wait for it
    }
}

func startServer(op binOp) chan *request {
    req := make(chan *request)
    go server(op, req)
    return req
}

func main() {
    adder := 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
    }
    for i := N - 1; i >= 0; i-- { // doesn't matter what order
        if <-reqs[i].replyc != N+2*i {
            fmt.Println("fail at", i)
        }
    }
    fmt.Println("done")
}