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https://gitee.com/milvus-io/milvus.git
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88 lines
2.4 KiB
Go
88 lines
2.4 KiB
Go
// Copyright (C) 2019-2020 Zilliz. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance
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// with the License. You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software distributed under the License
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// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
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// or implied. See the License for the specific language governing permissions and limitations under the License.
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package storage
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import (
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"bytes"
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"errors"
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)
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// BinlogReader is an object to read binlog file. Binlog file's format can be
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// found in design docs.
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type BinlogReader struct {
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magicNumber int32
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descriptorEvent
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buffer *bytes.Buffer
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eventList []*EventReader
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isClose bool
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}
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// NextEventReader iters all events reader to read the binlog file.
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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.buffer.Len() <= 0 {
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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.eventList = append(reader.eventList, eventReader)
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return eventReader, nil
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}
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func (reader *BinlogReader) readMagicNumber() (int32, error) {
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var err error
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reader.magicNumber, err = readMagicNumber(reader.buffer)
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return reader.magicNumber, err
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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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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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// Close closes the BinlogReader object.
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// It mainly calls the Close method of the internal events, reclaims resources, and marks itself as closed.
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func (reader *BinlogReader) Close() {
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if reader.isClose {
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return
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}
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for _, e := range reader.eventList {
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e.Close()
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}
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reader.isClose = true
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}
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// NewBinlogReader creates binlogReader to read binlog file.
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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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eventList: []*EventReader{},
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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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