add wave

galaxy/wave.go

@@ -0,0 +1,131 @@
+// Copyright 2019 The PDU Authors
+// This file is part of the PDU library.
+//
+// The PDU library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The PDU library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the PDU library. If not, see <http://www.gnu.org/licenses/>.
+
+package galaxy
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+)
+
+// WaveSize is the number of bytes in a wave
+// WaveHeaderSize 24 bytes + waveBody
+const WaveSize = 2048
+
+// MessageHeaderSize is the number of bytes in a wave header
+// command 12 bytes + length 4 bytes + checksum 4 bytes
+const WaveHeaderSize = 24
+
+// CommandSize is the fixed size of all commands
+const CommandSize = 12
+
+// Commands used in wave which describe the type of wave.
+const (
+	CmdQuestion = "question"
+	CmdVersion  = "version"
+	CmdRoots    = "roots"
+	CmdMessages = "messages"
+	CmdPing     = "ping"
+	CmdPong     = "aler"
+	CmdUser     = "user"
+)
+
+var (
+	errWaveLengthTooLong = errors.New("wave length too long")
+)
+
+// Wave is an interface that describes a galaxy information.
+type Wave interface {
+	Command() string
+}
+
+func makeEmptyWave(command string) (Wave, error) {
+	var wave Wave
+	switch command {
+	case CmdQuestion:
+		wave = &WaveQuestion{}
+	case CmdVersion:
+		wave = &WaveVersion{}
+	case CmdRoots:
+		wave = &WaveRoots{}
+	case CmdMessages:
+		wave = &WaveMessages{}
+	case CmdPing:
+		wave = &WavePing{}
+	case CmdPong:
+		wave = &WavePong{}
+	case CmdUser:
+		wave = &WaveUser{}
+	default:
+		return nil, fmt.Errorf("unhandled command [%s]", command)
+	}
+	return wave, nil
+}
+
+// SendWave send a wave message to w
+func SendWave(w io.Writer, wave Wave) (int, error) {
+	var magic, waveLen, checkSum [4]byte
+	var command [CommandSize]byte
+	cmd := wave.Command()
+	if len(cmd) > CommandSize {
+		return 0, fmt.Errorf("command [%s] is too long [max %v]", wave, CommandSize)
+	}
+	copy(command[:], []byte(cmd))
+	copy(magic[:], []byte(""))
+	copy(waveLen[:], []byte(""))
+	copy(checkSum[:], []byte(""))
+
+	waveHeader := bytes.NewBuffer(make([]byte, 0, WaveHeaderSize))
+	waveHeader.Write((magic[:]))
+	waveHeader.Write(command[:])
+	waveHeader.Write(waveLen[:])
+	waveHeader.Write(checkSum[:])
+	waveBody, err := json.Marshal(wave)
+	if err != nil {
+		return 0, err
+	}
+	waveBytes := append(waveHeader.Bytes(), waveBody...)
+	if len(waveBytes) > WaveSize {
+		return 0, errWaveLengthTooLong
+	}
+	return w.Write(waveBytes)
+}
+
+// ReceiveWave receive a wave message from r
+func ReceiveWave(r io.Reader) (Wave, error) {
+	waveBytes := make([]byte, WaveSize)
+	n, err := r.Read(waveBytes)
+	if err != nil {
+		return nil, err
+	}
+	waveHeader := waveBytes[:WaveHeaderSize]
+	waveBody := waveBytes[WaveHeaderSize:n]
+
+	// Strip trailing zeros from command string.
+	command := string(bytes.TrimRight(waveHeader[4:CommandSize+4], string(0)))
+	msg, err := makeEmptyWave(command)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := json.Unmarshal(waveBody, msg); err != nil {
+		return nil, err
+	}
+	return msg, nil
+}

galaxy/wave_test.go

@@ -0,0 +1,17 @@
+// Copyright 2019 The PDU Authors
+// This file is part of the PDU library.
+//
+// The PDU library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The PDU library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the PDU library. If not, see <http://www.gnu.org/licenses/>.
+
+package galaxy

galaxy/wavemsgs.go

@@ -0,0 +1,27 @@
+// Copyright 2019 The PDU Authors
+// This file is part of the PDU library.
+//
+// The PDU library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The PDU library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the PDU library. If not, see <http://www.gnu.org/licenses/>.
+
+package galaxy
+
+// WaveMessages implements the Wave interface and represents a broadcast new message.
+type WaveMessages struct {
+	Msgs [][]byte `json:"msgs"`
+}
+
+// Command returns the protocol command string for the wave.
+func (w *WaveMessages) Command() string {
+	return CmdMessages
+}

galaxy/waveping.go

@@ -0,0 +1,26 @@
+// Copyright 2019 The PDU Authors
+// This file is part of the PDU library.
+//
+// The PDU library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The PDU library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the PDU library. If not, see <http://www.gnu.org/licenses/>.
+
+package galaxy
+
+// WavePing implements the Wave interface and represents a ping message
+type WavePing struct {
+}
+
+// Command returns the protocol command string for the wave.
+func (w *WavePing) Command() string {
+	return CmdPing
+}

galaxy/wavepong.go

@@ -0,0 +1,26 @@
+// Copyright 2019 The PDU Authors
+// This file is part of the PDU library.
+//
+// The PDU library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The PDU library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the PDU library. If not, see <http://www.gnu.org/licenses/>.
+
+package galaxy
+
+// WavePong implements the Wave interface and represents a pong message
+type WavePong struct {
+}
+
+// Command returns the protocol command string for the wave.
+func (w *WavePong) Command() string {
+	return CmdPong
+}

galaxy/wavequestion.go

@@ -0,0 +1,26 @@
+// Copyright 2019 The PDU Authors
+// This file is part of the PDU library.
+//
+// The PDU library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The PDU library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the PDU library. If not, see <http://www.gnu.org/licenses/>.
+
+package galaxy
+
+// WaveQuestion implements the Wave interface and represents request info message.
+type WaveQuestion struct {
+}
+
+// Command returns the protocol command string for the wave.
+func (w *WaveQuestion) Command() string {
+	return CmdQuestion
+}

galaxy/waveroots.go

@@ -0,0 +1,26 @@
+// Copyright 2019 The PDU Authors
+// This file is part of the PDU library.
+//
+// The PDU library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The PDU library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the PDU library. If not, see <http://www.gnu.org/licenses/>.
+
+package galaxy
+
+// WaveRoots implements the Wave interface and represents a getRoots message.
+type WaveRoots struct {
+}
+
+// Command returns the protocol command string for the wave.
+func (w *WaveRoots) Command() string {
+	return CmdRoots
+}

galaxy/waveuser.go

@@ -0,0 +1,26 @@
+// Copyright 2019 The PDU Authors
+// This file is part of the PDU library.
+//
+// The PDU library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The PDU library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the PDU library. If not, see <http://www.gnu.org/licenses/>.
+
+package galaxy
+
+// WaveUser implements the Wave interface and represents a checkUser message.
+type WaveUser struct {
+}
+
+// Command returns the protocol command string for the wave.
+func (w *WaveUser) Command() string {
+	return CmdUser
+}

galaxy/waveversion.go

@@ -0,0 +1,26 @@
+// Copyright 2019 The PDU Authors
+// This file is part of the PDU library.
+//
+// The PDU library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The PDU library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the PDU library. If not, see <http://www.gnu.org/licenses/>.
+
+package galaxy
+
+// WaveVersion implements the Wave interface and represents a galaxy protocol version message.
+type WaveVersion struct {
+}
+
+// Command returns the protocol command string for the wave.
+func (w *WaveVersion) Command() string {
+	return CmdVersion
+}