mirror of
https://gitee.com/milvus-io/milvus.git
synced 2026-01-07 19:31:51 +08:00
100 lines
2.5 KiB
Go
100 lines
2.5 KiB
Go
package storage
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import (
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"bytes"
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"encoding/binary"
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"strconv"
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"github.com/zilliztech/milvus-distributed/internal/errors"
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)
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type BinlogReader struct {
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magicNumber int32
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descriptorEvent
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currentEventReader *EventReader
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buffer *bytes.Buffer
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bufferLength int
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currentOffset int32
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isClose bool
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}
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func (reader *BinlogReader) NextEventReader() (*EventReader, error) {
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if reader.isClose {
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return nil, errors.New("bin log reader is closed")
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}
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if reader.currentEventReader != nil {
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reader.currentOffset = reader.currentEventReader.NextPosition
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if err := reader.currentEventReader.Close(); err != nil {
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return nil, err
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}
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reader.currentEventReader = nil
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if reader.currentOffset >= int32(reader.buffer.Len()) {
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return nil, nil
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}
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// skip remaining bytes of this event
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remaining := int(reader.currentOffset) - (reader.bufferLength - reader.buffer.Len())
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reader.buffer.Next(remaining)
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}
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if reader.currentOffset >= int32(reader.buffer.Len()) {
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return nil, nil
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}
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eventReader, err := newEventReader(reader.descriptorEvent.PayloadDataType, reader.buffer)
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if err != nil {
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return nil, err
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}
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reader.currentEventReader = eventReader
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return reader.currentEventReader, nil
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}
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func (reader *BinlogReader) readMagicNumber() (int32, error) {
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if err := binary.Read(reader.buffer, binary.LittleEndian, &reader.magicNumber); err != nil {
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return -1, err
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}
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reader.currentOffset = 4
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if reader.magicNumber != MagicNumber {
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return -1, errors.New("parse magic number failed, expected: " + strconv.Itoa(MagicNumber) +
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", actual: " + strconv.Itoa(int(reader.magicNumber)))
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}
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return reader.magicNumber, nil
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}
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func (reader *BinlogReader) readDescriptorEvent() (*descriptorEvent, error) {
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event, err := ReadDescriptorEvent(reader.buffer)
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reader.currentOffset = event.NextPosition
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if err != nil {
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return nil, err
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}
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reader.descriptorEvent = *event
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return &reader.descriptorEvent, nil
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}
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func (reader *BinlogReader) Close() error {
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if reader.isClose {
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return nil
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}
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reader.isClose = true
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if reader.currentEventReader != nil {
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if err := reader.currentEventReader.Close(); err != nil {
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return err
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}
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}
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return nil
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}
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func NewBinlogReader(data []byte) (*BinlogReader, error) {
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reader := &BinlogReader{
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buffer: bytes.NewBuffer(data),
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bufferLength: len(data),
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isClose: false,
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}
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if _, err := reader.readMagicNumber(); err != nil {
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return nil, err
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}
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if _, err := reader.readDescriptorEvent(); err != nil {
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return nil, err
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}
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return reader, nil
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}
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