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package tanja
import (
"bufio"
"encoding/json"
"errors"
. "strconv"
)
type linkMsgPatternsync bool
type linkMsgRegister struct {
pid int32
pat Tuple
}
type linkMsgRegdone struct{}
type linkMsgUnregister int32
type linkMsgTuple struct {
tid int32
tup Tuple
}
type linkMsgReply struct {
tid int32
tup Tuple
}
type linkMsgClose int32
type linkMsgJSON struct {
m interface{}
}
// Make sure JSON arrays are read as tuples. For anything else, just use the
// generic to-interface{} conversion.
func (j *linkMsgJSON) UnmarshalJSON(data []byte) (err error) {
if data[0] == '[' {
var t Tuple
err = json.Unmarshal(data, &t)
j.m = t
} else {
err = json.Unmarshal(data, &j.m)
}
return
}
func linkMsgRead(rd *bufio.Reader) (msg interface{}, err error) {
var line []byte
var prefix bool
line, prefix, err = rd.ReadLine()
if prefix || err != nil {
if err == nil {
err = errors.New("Read buffer overflow.")
}
return
}
var m []linkMsgJSON
if err = json.Unmarshal(line, &m); err != nil || len(m) < 1 {
if len(m) < 1 {
err = errors.New("Invalid message type.")
}
return
}
// Validate and convert
typ, ok := m[0].m.(float64)
if !ok {
err = errors.New("Invalid message type.")
return
}
// Copy-pasting is bad, mkay?
switch int32(typ) {
case 1: // patternsync
if len(m) != 2 {
err = errors.New("Invalid number of arguments for the patternsync message.")
} else if val, ok := m[1].m.(bool); ok {
msg = linkMsgPatternsync(val)
} else {
err = errors.New("Invalid type of second argument to the patternsync message.")
}
case 2: // register
var pid float64
var pat Tuple
if len(m) != 3 {
err = errors.New("Invalid number of arguments for the register message.")
} else if pid, ok = m[1].m.(float64); !ok {
err = errors.New("Invalid type of second argument to the patternsync message.")
} else if pat, ok = m[2].m.(Tuple); !ok {
err = errors.New("Invalid type of third argument to the patternsync message.")
} else {
msg = &linkMsgRegister{int32(pid), pat}
}
case 3: // regdone
if len(m) != 1 {
err = errors.New("Invalid number of arguments for the regdone message.")
} else {
msg = linkMsgRegdone{}
}
case 4: // unregister
if len(m) != 2 {
err = errors.New("Invalid number of arguments for the unregister message.")
} else if val, ok := m[1].m.(float64); ok {
msg = linkMsgUnregister(int32(val))
} else {
err = errors.New("Invalid type of second argument to the unregister message.")
}
case 5: // tuple
var tid float64
var tup Tuple
if len(m) != 3 {
err = errors.New("Invalid number of arguments for the tuple message.")
} else if tid, ok = m[1].m.(float64); !ok {
err = errors.New("Invalid type of second argument to the tuple message.")
} else if tup, ok = m[2].m.(Tuple); !ok {
err = errors.New("Invalid type of third argument to the tuple message.")
} else {
msg = &linkMsgTuple{int32(tid), tup}
}
case 6: // reply
var tid float64
var tup Tuple
if len(m) != 3 {
err = errors.New("Invalid number of arguments for the reply message.")
} else if tid, ok = m[1].m.(float64); !ok {
err = errors.New("Invalid type of second argument to the reply message.")
} else if tup, ok = m[2].m.(Tuple); !ok {
err = errors.New("Invalid type of third argument to the reply message.")
} else {
msg = &linkMsgReply{int32(tid), tup}
}
case 7: // close
if len(m) != 2 {
err = errors.New("Invalid number of arguments for the close message.")
} else if val, ok := m[1].m.(float64); ok {
msg = linkMsgClose(int32(val))
} else {
err = errors.New("Invalid type of second argument to the close message.")
}
}
// Ignore unknown messages by returning nil without error
return
}
func linkMsgFmt(msg interface{}, buf []byte) []byte {
// Somewhat low-level, but oh well
switch m := msg.(type) {
case linkMsgPatternsync:
if m {
buf = append(buf, []byte("[1,true]\n")...)
} else {
buf = append(buf, []byte("[1,false]\n")...)
}
case *linkMsgRegister:
buf = append(buf, []byte("[2,")...)
buf = append(buf, []byte(FormatInt(int64(m.pid), 10))...)
buf = append(buf, ',')
dat, _ := json.Marshal(m.pat)
buf = append(buf, dat...)
buf = append(buf, []byte("]\n")...)
case linkMsgRegdone:
buf = append(buf, []byte("[3]\n")...)
case linkMsgUnregister:
buf = append(buf, []byte("[4,")...)
buf = append(buf, []byte(FormatInt(int64(m), 10))...)
buf = append(buf, []byte("]\n")...)
case *linkMsgTuple:
buf = append(buf, []byte("[5,")...)
buf = append(buf, []byte(FormatInt(int64(m.tid), 10))...)
buf = append(buf, ',')
dat, _ := json.Marshal(m.tup)
buf = append(buf, dat...)
buf = append(buf, []byte("]\n")...)
case *linkMsgReply:
buf = append(buf, []byte("[6,")...)
buf = append(buf, []byte(FormatInt(int64(m.tid), 10))...)
buf = append(buf, ',')
dat, _ := json.Marshal(m.tup)
buf = append(buf, dat...)
buf = append(buf, []byte("]\n")...)
case linkMsgClose:
buf = append(buf, []byte("[7,")...)
buf = append(buf, []byte(FormatInt(int64(m), 10))...)
buf = append(buf, []byte("]\n")...)
}
return buf
}
|