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// Copyright 2018 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 jsonrpc2
import (
"context"
"io"
"net"
"os"
)
// This file contains implementations of the transport primitives that use the standard network
// package.
// NetListenOptions is the optional arguments to the NetListen function.
type NetListenOptions struct {
NetListenConfig net.ListenConfig
NetDialer net.Dialer
}
// NetListener returns a new Listener that listens on a socket using the net package.
func NetListener(ctx context.Context, network, address string, options NetListenOptions) (Listener, error) {
ln, err := options.NetListenConfig.Listen(ctx, network, address)
if err != nil {
return nil, err
}
return &netListener{net: ln}, nil
}
// netListener is the implementation of Listener for connections made using the net package.
type netListener struct {
net net.Listener
}
// Accept blocks waiting for an incoming connection to the listener.
func (l *netListener) Accept(context.Context) (io.ReadWriteCloser, error) {
return l.net.Accept()
}
// Close will cause the listener to stop listening. It will not close any connections that have
// already been accepted.
func (l *netListener) Close() error {
addr := l.net.Addr()
err := l.net.Close()
if addr.Network() == "unix" {
rerr := os.Remove(addr.String())
if rerr != nil && err == nil {
err = rerr
}
}
return err
}
// Dialer returns a dialer that can be used to connect to the listener.
func (l *netListener) Dialer() Dialer {
return NetDialer(l.net.Addr().Network(), l.net.Addr().String(), net.Dialer{})
}
// NetDialer returns a Dialer using the supplied standard network dialer.
func NetDialer(network, address string, nd net.Dialer) Dialer {
return &netDialer{
network: network,
address: address,
dialer: nd,
}
}
type netDialer struct {
network string
address string
dialer net.Dialer
}
func (n *netDialer) Dial(ctx context.Context) (io.ReadWriteCloser, error) {
return n.dialer.DialContext(ctx, n.network, n.address)
}
// NetPipeListener returns a new Listener that listens using net.Pipe.
// It is only possibly to connect to it using the Dialer returned by the
// Dialer method, each call to that method will generate a new pipe the other
// side of which will be returned from the Accept call.
func NetPipeListener(ctx context.Context) (Listener, error) {
return &netPiper{
done: make(chan struct{}),
dialed: make(chan io.ReadWriteCloser),
}, nil
}
// netPiper is the implementation of Listener build on top of net.Pipes.
type netPiper struct {
done chan struct{}
dialed chan io.ReadWriteCloser
}
// Accept blocks waiting for an incoming connection to the listener.
func (l *netPiper) Accept(context.Context) (io.ReadWriteCloser, error) {
// Block until the pipe is dialed or the listener is closed,
// preferring the latter if already closed at the start of Accept.
select {
case <-l.done:
return nil, errClosed
default:
}
select {
case rwc := <-l.dialed:
return rwc, nil
case <-l.done:
return nil, errClosed
}
}
// Close will cause the listener to stop listening. It will not close any connections that have
// already been accepted.
func (l *netPiper) Close() error {
// unblock any accept calls that are pending
close(l.done)
return nil
}
func (l *netPiper) Dialer() Dialer {
return l
}
func (l *netPiper) Dial(ctx context.Context) (io.ReadWriteCloser, error) {
client, server := net.Pipe()
select {
case l.dialed <- server:
return client, nil
case <-l.done:
client.Close()
server.Close()
return nil, errClosed
}
}