Move data track packet serialization from livekit package

.changeset/lovely-heads-think.md

@@ -0,0 +1,6 @@
+---
+"github.com/livekit/protocol": minor
+"@livekit/protocol": minor
+---
+
+Move data track packet serialization from livekit package

datatrack/datatracktest/testutils.go

@@ -0,0 +1,77 @@
+// Copyright 2023 LiveKit, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package datatracktest provides helpers for generating data track packets in tests.
+package datatracktest
+
+import (
+	"math/rand"
+	"time"
+
+	"github.com/livekit/protocol/datatrack"
+)
+
+func GenerateRawDataPackets(handle uint16, seqNum uint16, frameNum uint16, numFrames int, frameSize int, frameDuration time.Duration) [][]byte {
+	if seqNum == 0 {
+		seqNum = uint16(rand.Intn(256) + 1)
+	}
+	if frameNum == 0 {
+		frameNum = uint16(rand.Intn(256) + 1)
+	}
+	timestamp := uint32(rand.Intn(1024))
+
+	packetsPerFrame := (frameSize + 255) / 256 // using 256 bytes of payload per packet
+	if packetsPerFrame == 0 {
+		return nil
+	}
+	numPackets := packetsPerFrame * numFrames
+	rawPackets := make([][]byte, 0, numPackets)
+	for range numFrames {
+		remainingSize := frameSize
+		for packetIdx := range packetsPerFrame {
+			payloadSize := min(remainingSize, 256)
+			payload := make([]byte, payloadSize)
+			for i := range len(payload) {
+				payload[i] = byte(255 - i)
+			}
+			packet := &datatrack.Packet{
+				Header: datatrack.Header{
+					Version:        0,
+					IsStartOfFrame: packetIdx == 0,
+					IsFinalOfFrame: packetIdx == packetsPerFrame-1,
+					Handle:         handle,
+					SequenceNumber: seqNum,
+					FrameNumber:    frameNum,
+					Timestamp:      timestamp,
+				},
+				Payload: payload,
+			}
+			if extParticipantSid, err := datatrack.NewExtensionParticipantSid("test_participant"); err == nil {
+				if ext, err := extParticipantSid.Marshal(); err == nil {
+					packet.AddExtension(ext)
+				}
+			}
+			rawPacket, err := packet.Marshal()
+			if err == nil {
+				rawPackets = append(rawPackets, rawPacket)
+			}
+			seqNum++
+			remainingSize -= payloadSize
+		}
+		frameNum++
+		timestamp += uint32(90000 * frameDuration.Seconds())
+	}
+
+	return rawPackets
+}

datatrack/extension_participant_sid.go

@@ -0,0 +1,59 @@
+// Copyright 2023 LiveKit, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package datatrack
+
+import (
+	"errors"
+
+	"github.com/livekit/protocol/livekit"
+)
+
+type ExtensionParticipantSid struct {
+	participantID livekit.ParticipantID
+}
+
+func NewExtensionParticipantSid(participantID livekit.ParticipantID) (*ExtensionParticipantSid, error) {
+	if len(participantID) >= 256 {
+		return nil, errors.New("participantID too long")
+	}
+
+	return &ExtensionParticipantSid{participantID}, nil
+}
+
+func (e *ExtensionParticipantSid) ParticipantID() livekit.ParticipantID {
+	return e.participantID
+}
+
+func (e *ExtensionParticipantSid) Marshal() (Extension, error) {
+	data := make([]byte, len(e.participantID))
+	copy(data, e.participantID)
+	return Extension{
+		id:   uint8(livekit.DataTrackExtensionID_DTEI_PARTICIPANT_SID),
+		data: data,
+	}, nil
+}
+
+func (e *ExtensionParticipantSid) Unmarshal(ext Extension) error {
+	if ext.id != uint8(livekit.DataTrackExtensionID_DTEI_PARTICIPANT_SID) {
+		return errors.New("invalid extension ID")
+	}
+
+	if len(ext.data) == 0 {
+		return errors.New("empty extension data")
+	}
+
+	e.participantID = livekit.ParticipantID(ext.data)
+	return nil
+}

datatrack/extension_participant_sid_test.go

@@ -0,0 +1,46 @@
+// Copyright 2023 LiveKit, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package datatrack
+
+import (
+	"testing"
+
+	"github.com/livekit/protocol/livekit"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestExtensionParticipantSid(t *testing.T) {
+	longTestParticipantID := livekit.ParticipantID(make([]byte, 256))
+	_, err := NewExtensionParticipantSid(longTestParticipantID)
+	require.Error(t, err)
+
+	testParticipantID := livekit.ParticipantID("test")
+	extParticipantSid, err := NewExtensionParticipantSid(testParticipantID)
+	require.NoError(t, err)
+
+	expectedExt := Extension{
+		id:   uint8(livekit.DataTrackExtensionID_DTEI_PARTICIPANT_SID),
+		data: []byte{'t', 'e', 's', 't'},
+	}
+	ext, err := extParticipantSid.Marshal()
+	require.NoError(t, err)
+	require.Equal(t, expectedExt, ext)
+
+	var unmarshaled ExtensionParticipantSid
+	err = unmarshaled.Unmarshal(ext)
+	require.NoError(t, err)
+	assert.Equal(t, testParticipantID, unmarshaled.ParticipantID())
+}