87 lines
2.4 KiB
Go
87 lines
2.4 KiB
Go
// Copyright 2023 PingCAP, 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 external
|
|
|
|
import (
|
|
"context"
|
|
|
|
"github.com/pingcap/tidb/pkg/objstore/objectio"
|
|
)
|
|
|
|
const (
|
|
statSuffix = "_stat"
|
|
dupSuffix = "_dup"
|
|
// we use uint64 to store the length of key and value.
|
|
lengthBytes = 8
|
|
)
|
|
|
|
// KeyValueStore stores key-value pairs and maintains the range properties.
|
|
type KeyValueStore struct {
|
|
dataWriter objectio.Writer
|
|
|
|
rc *rangePropertiesCollector
|
|
ctx context.Context
|
|
offset uint64
|
|
}
|
|
|
|
// NewKeyValueStore creates a new KeyValueStore. The data will be written to the
|
|
// given dataWriter and range properties will be maintained in the given
|
|
// rangePropertiesCollector.
|
|
func NewKeyValueStore(
|
|
ctx context.Context,
|
|
dataWriter objectio.Writer,
|
|
rangePropertiesCollector *rangePropertiesCollector,
|
|
) *KeyValueStore {
|
|
kvStore := &KeyValueStore{
|
|
dataWriter: dataWriter,
|
|
ctx: ctx,
|
|
rc: rangePropertiesCollector,
|
|
}
|
|
return kvStore
|
|
}
|
|
|
|
// addEncodedData saves encoded key-value pairs to the KeyValueStore.
|
|
// data layout: keyLen + valueLen + key + value. If the accumulated
|
|
// size or key count exceeds the given distance, a new range property will be
|
|
// appended to the rangePropertiesCollector with current status.
|
|
// `key` must be in strictly ascending order for invocations of a KeyValueStore.
|
|
func (s *KeyValueStore) addEncodedData(data []byte) error {
|
|
_, err := s.dataWriter.Write(s.ctx, data)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
s.offset += uint64(len(data))
|
|
if s.rc != nil {
|
|
s.rc.onNextEncodedData(data, s.offset)
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func (s *KeyValueStore) addRawKV(key, val []byte) error {
|
|
length := len(key) + len(val) + lengthBytes*2
|
|
buf := make([]byte, length)
|
|
encodeToBuf(buf, key, val)
|
|
return s.addEncodedData(buf[:length])
|
|
}
|
|
|
|
// finish closes the KeyValueStore and append the last range property.
|
|
func (s *KeyValueStore) finish() {
|
|
if s.rc != nil {
|
|
s.rc.onFileEnd()
|
|
}
|
|
}
|