60 lines
1.8 KiB
Go
60 lines
1.8 KiB
Go
// Copyright 2015 PingCAP, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// 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
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// distributed under the License is distributed on an "AS IS" BASIS,
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package localstore
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import (
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"github.com/juju/errors"
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"github.com/pingcap/tidb/kv"
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"github.com/pingcap/tidb/util/codec"
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)
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// ErrInvalidEncodedKey describes parsing an invalid format of EncodedKey.
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var ErrInvalidEncodedKey = errors.New("invalid encoded key")
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func isTombstone(v []byte) bool {
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return len(v) == 0
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}
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// MvccEncodeVersionKey returns the encoded key.
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func MvccEncodeVersionKey(key kv.Key, ver kv.Version) kv.EncodedKey {
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b := codec.EncodeBytes(nil, key)
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ret := codec.EncodeUintDesc(b, ver.Ver)
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return ret
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}
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// MvccDecode parses the origin key and version of an encoded key, if the encoded key is a meta key,
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// just returns the origin key.
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func MvccDecode(encodedKey kv.EncodedKey) (kv.Key, kv.Version, error) {
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// Skip DataPrefix
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remainBytes, key, err := codec.DecodeBytes([]byte(encodedKey))
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if err != nil {
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// should never happen
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return nil, kv.Version{}, errors.Trace(err)
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}
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// if it's meta key
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if len(remainBytes) == 0 {
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return key, kv.Version{}, nil
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}
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var ver uint64
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remainBytes, ver, err = codec.DecodeUintDesc(remainBytes)
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if err != nil {
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// should never happen
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return nil, kv.Version{}, errors.Trace(err)
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}
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if len(remainBytes) != 0 {
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return nil, kv.Version{}, ErrInvalidEncodedKey
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}
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return key, kv.Version{Ver: ver}, nil
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}
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