blockchain-go/p2p/conn.go

package p2p

import (
	"blockchain-go/p2p/enode"
	"net"
	"sync/atomic"
)

type connFlag int32

func (f connFlag) String() string {
	s := ""
	if f&trustedConn != 0 {
		s += "-trusted"
	}
	if f&dynDialedConn != 0 {
		s += "-dyndial"
	}
	if f&staticDialedConn != 0 {
		s += "-staticdial"
	}
	if f&inboundConn != 0 {
		s += "-inbound"
	}
	if s != "" {
		s = s[1:]
	}
	return s
}

const (
	dynDialedConn connFlag = 1 << iota
	staticDialedConn
	inboundConn
	trustedConn
)

// conn wraps a network connection with information gathered
// during the two handshakes.
type conn struct {
	fd net.Conn
	transport
	node  *enode.Node
	flags connFlag
	cont  chan error // The run loop uses cont to signal errors to SetupConn.
	caps  []Cap      // valid after the protocol handshake
	name  string     // valid after the protocol handshake
}

func (c *conn) String() string {
	s := c.flags.String()
	if (c.node.ID() != enode.ID{}) {
		s += " " + c.node.ID().String()
	}
	s += " " + c.fd.RemoteAddr().String()
	return s
}

func (c *conn) is(f connFlag) bool {
	flags := connFlag(atomic.LoadInt32((*int32)(&c.flags)))
	return flags&f != 0
}

func (c *conn) set(f connFlag, val bool) {
	for {
		oldFlags := connFlag(atomic.LoadInt32((*int32)(&c.flags)))
		flags := oldFlags
		if val {
			flags |= f
		} else {
			flags &= ^f
		}
		if atomic.CompareAndSwapInt32((*int32)(&c.flags), int32(oldFlags), int32(flags)) {
			return
		}
	}
}