func NewConn(rwc io.ReadWriteCloser) (*Conn, error) {
c := &Conn{
rwc: rwc,
tagmap: make(map[uint16]chan *plan9.Fcall),
freetag: make(map[uint16]bool),
freefid: make(map[uint32]bool),
nexttag: 1,
nextfid: 1,
msize: 131072,
version: "9P2000",
}
// XXX raw messages, not c.rpc
tx := &plan9.Fcall{Type: plan9.Tversion, Msize: c.msize, Version: c.version}
rx, err := c.rpc(tx)
if err != nil {
return nil, err
}
if rx.Msize > c.msize {
return nil, plan9.ProtocolError(fmt.Sprintf("invalid msize %d in Rversion", rx.Msize))
}
c.msize = rx.Msize
if rx.Version != "9P2000" {
return nil, plan9.ProtocolError(fmt.Sprintf("invalid version %s in Rversion", rx.Version))
}
return c, nil
}
func (c *Conn) rpc(tx *plan9.Fcall) (rx *plan9.Fcall, err error) {
ch := make(chan *plan9.Fcall, 1)
tx.Tag, err = c.newtag(ch)
if err != nil {
return nil, err
}
c.w.Lock()
if err := c.write(tx); err != nil {
c.w.Unlock()
return nil, err
}
c.w.Unlock()
for rx = range ch {
if rx != &yourTurn {
break
}
rx, err = c.read()
if err != nil {
break
}
c.mux(rx)
}
if rx == nil {
return nil, c.getErr()
}
if rx.Type == plan9.Rerror {
return nil, Error(rx.Ename)
}
if rx.Type != tx.Type+1 {
return nil, plan9.ProtocolError("packet type mismatch")
}
return rx, nil
}
func (c *Conn) newfid() (*Fid, error) {
c.x.Lock()
defer c.x.Unlock()
var fidnum uint32
for fidnum, _ = range c.freefid {
delete(c.freefid, fidnum)
goto found
}
fidnum = c.nextfid
if c.nextfid == plan9.NOFID {
return nil, plan9.ProtocolError("out of fids")
}
c.nextfid++
found:
return &Fid{fid: fidnum, c: c}, nil
}
func (c *Conn) newtag(ch chan *plan9.Fcall) (uint16, error) {
c.x.Lock()
defer c.x.Unlock()
var tagnum uint16
for tagnum, _ = range c.freetag {
delete(c.freetag, tagnum)
goto found
}
tagnum = c.nexttag
if c.nexttag == plan9.NOTAG {
return 0, plan9.ProtocolError("out of tags")
}
c.nexttag++
found:
c.tagmap[tagnum] = ch
if !c.muxer {
c.muxer = true
ch <- &yourTurn
}
return tagnum, nil
}