func (cli *LspClient) iRead() ([]byte, error) {
lsplog.Vlogf(2, "[Client] Application is attempting to read")
if cli.connectionAlive {
element := cli.read.Remove()
if element == nil {
return nil, lsplog.MakeErr("Connection is lost with server")
}
return element.([]byte), nil
}
return nil, lsplog.MakeErr("Connection is lost. Cannot read.")
}
func (cli *LspClient) iWrite(payload []byte) error {
lsplog.Vlogf(2, "[Client] Application is attempting to write")
if cli.connectionAlive {
go cli.iWriteHandler(payload) // Defers reading to the write handler so the application don't get blocked.
return nil
}
return lsplog.MakeErr("Connection is no alive. Payload is ignored.")
}
// Write message to specified client
func (srv *LspServer) iWrite(connId uint16, payload []byte) error {
lsplog.Vlogf(2, "[Server] Application is writing")
for _, v := range srv.clients { // Looks for the client to send
if v.connId == connId {
m := CreateDataPacket(connId, v.serverSeqNum, payload)
go srv.iWriteHandler(m, v)
return nil
}
}
return lsplog.MakeErr("Could not find specified connId")
}
func iNewLspClient(hostport string, params *LspParams) (*LspClient, error) {
cli := new(LspClient)
if params == nil {
// Insert default parameters
params = &LspParams{5, 2000}
}
cli.params = params
addr, err := lspnet.ResolveUDPAddr("udp", hostport)
if lsplog.CheckReport(1, err) {
return nil, err
}
cli.lspConn = newConn(addr, 0, 0)
// Client's first received message will be data message.
cli.lspConn.nextRecvSeqNum = NextSeqNum(0)
cli.udpConn, err = lspnet.DialUDP("udp", nil, addr)
if lsplog.CheckReport(1, err) {
return nil, err
}
// Need enough room to recycle close messages at end
cli.appReadChan = make(LspMessageChan, 2)
cli.readBuf = NewBuf()
cli.appWriteChan = make(LspMessageChan, 1)
cli.netInChan = make(LspMessageChan, 1)
cli.epochChan = make(chan int)
cli.closeReplyChan = make(chan error, 2)
cli.writeReplyChan = make(chan error, 2)
go cli.clientLoop()
go cli.udpReader()
go epochTrigger(cli.params.EpochMilliseconds, cli.epochChan, &cli.lspConn.stopNetworkFlag)
// Send connection request to server
nm := GenConnectMessage()
cli.udpWrite(nm)
cli.lspConn.pendingMsg = nm
cli.lspConn.nextSendSeqNum = NextSeqNum(0)
cm := <-cli.appReadChan
if cm.Type == MsgCONNECT {
return cli, nil
}
return nil, lsplog.MakeErr("Connection failed")
}