network/frame/data_frame.go

package frame

import (
	"fmt"
	coder "git.hpds.cc/Component/mq_coder"
	"sync"
)

var dataFramePool sync.Pool

// DataFrame defines the data structure carried with user's data
type DataFrame struct {
	metaFrame    *MetaFrame
	payloadFrame *PayloadFrame
}

func (d *DataFrame) String() string {
	data := d.GetCarriage()
	length := len(data)
	if length > debugFrameSize {
		data = data[:debugFrameSize]
	}
	return fmt.Sprintf("tid=%s | tag=%#x | source=%s | data[%d]=%# x", d.metaFrame.tid, d.Tag(), d.SourceId(), length, data)
}

// NewDataFrame create `DataFrame` with a transactionId string,
// consider change transactionID to UUID type later
func NewDataFrame() *DataFrame {
	data := newDataFrame()
	data.metaFrame.tid = randString()
	return data
}

func newDataFrame() (data *DataFrame) {
	v := dataFramePool.Get()
	if v == nil {
		data = new(DataFrame)
		data.metaFrame = new(MetaFrame)
		data.payloadFrame = new(PayloadFrame)
	} else {
		data = v.(*DataFrame)
	}

	return
}

// Clean cleans DataFrame.
// Note that:
// 1/ if the client is calling WriteFrame(), it will automatically invoke Clean(), so there is no need to call Clean() separately.
// 2/ The DataFrame will be unavailable after cleaned, do not access DataFrame after Clean() called.
func (d *DataFrame) Clean() {
	// reset metadataFrame
	d.metaFrame.tid = ""
	d.metaFrame.metadata = d.metaFrame.metadata[:0]
	d.metaFrame.sourceId = ""
	d.metaFrame.broadcast = false

	// reset payloadFrame
	d.payloadFrame.Tag = Tag(0)
	d.payloadFrame.Carriage = d.payloadFrame.Carriage[:0]

	dataFramePool.Put(d)
}

// Type gets the type of Frame.
func (d *DataFrame) Type() Type {
	return TagOfDataFrame
}

// Tag return the tag of carriage data.
func (d *DataFrame) Tag() Tag {
	return d.payloadFrame.Tag
}

// SetCarriage set user's raw data in `DataFrame`
func (d *DataFrame) SetCarriage(tag Tag, carriage []byte) {
	d.payloadFrame = &PayloadFrame{
		Tag:      tag,
		Carriage: carriage,
	}
}

// GetCarriage return user's raw data in `DataFrame`
func (d *DataFrame) GetCarriage() []byte {
	return d.payloadFrame.Carriage
}

// TransactionId return transactionId string
func (d *DataFrame) TransactionId() string {
	return d.metaFrame.TransactionId()
}

// SetTransactionId set transactionId string
func (d *DataFrame) SetTransactionId(transactionId string) {
	d.metaFrame.SetTransactionId(transactionId)
}

// GetMetaFrame return MetaFrame.
func (d *DataFrame) GetMetaFrame() *MetaFrame {
	return d.metaFrame
}

// GetDataTag return the Tag of user's data
func (d *DataFrame) GetDataTag() Tag {
	return d.payloadFrame.Tag
}

// SetSourceId set the source id.
func (d *DataFrame) SetSourceId(sourceId string) {
	d.metaFrame.SetSourceId(sourceId)
}

// SourceId returns source id
func (d *DataFrame) SourceId() string {
	return d.metaFrame.SourceId()
}

// SetBroadcast set broadcast mode
func (d *DataFrame) SetBroadcast(enabled bool) {
	d.metaFrame.SetBroadcast(enabled)
}

// IsBroadcast returns the broadcast mode is enabled
func (d *DataFrame) IsBroadcast() bool {
	return d.metaFrame.IsBroadcast()
}

// Encode return coder encoded bytes of `DataFrame`
func (d *DataFrame) Encode() []byte {
	data := coder.NewNodePacketEncoder(byte(d.Type()))
	// MetaFrame
	data.AddBytes(d.metaFrame.Encode())
	// PayloadFrame
	data.AddBytes(d.payloadFrame.Encode())

	return data.Encode()
}

// DecodeToDataFrame decode coder encoded bytes to `DataFrame`
func DecodeToDataFrame(buf []byte) (*DataFrame, error) {
	packet := coder.NodePacket{}
	_, err := coder.DecodeToNodePacket(buf, &packet)
	if err != nil {
		return nil, err
	}

	data := new(DataFrame)
	data.metaFrame = new(MetaFrame)
	data.payloadFrame = new(PayloadFrame)

	if metaBlock, ok := packet.NodePackets[byte(TagOfMetaFrame)]; ok {
		err := DecodeToMetaFrame(metaBlock.GetRawBytes(), data.metaFrame)
		if err != nil {
			return nil, err
		}
	}

	if payloadBlock, ok := packet.NodePackets[byte(TagOfPayloadFrame)]; ok {
		err := DecodeToPayloadFrame(payloadBlock.GetRawBytes(), data.payloadFrame)
		if err != nil {
			return nil, err
		}
	}

	return data, nil
}