tidb string 源码
tidb string 代码
文件路径：/structure/string.go
// Copyright 2015 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 structure
import (
"context"
"strconv"
"github.com/pingcap/errors"
"github.com/pingcap/tidb/kv"
)
// Set sets the string value of the key.
func (t *TxStructure) Set(key []byte, value []byte) error {
if t.readWriter == nil {
return ErrWriteOnSnapshot
}
ek := t.encodeStringDataKey(key)
return t.readWriter.Set(ek, value)
}
// Get gets the string value of a key.
func (t *TxStructure) Get(key []byte) ([]byte, error) {
ek := t.encodeStringDataKey(key)
value, err := t.reader.Get(context.TODO(), ek)
if kv.ErrNotExist.Equal(err) {
err = nil
}
return value, errors.Trace(err)
}
// GetInt64 gets the int64 value of a key.
func (t *TxStructure) GetInt64(key []byte) (int64, error) {
v, err := t.Get(key)
if err != nil || v == nil {
return 0, errors.Trace(err)
}
n, err := strconv.ParseInt(string(v), 10, 64)
return n, errors.Trace(err)
}
// Inc increments the integer value of a key by step, returns
// the value after the increment.
func (t *TxStructure) Inc(key []byte, step int64) (int64, error) {
if t.readWriter == nil {
return 0, ErrWriteOnSnapshot
}
ek := t.encodeStringDataKey(key)
// txn Inc will lock this key, so we don't lock it here.
n, err := kv.IncInt64(t.readWriter, ek, step)
if kv.ErrNotExist.Equal(err) {
err = nil
}
return n, errors.Trace(err)
}
// Clear removes the string value of the key.
func (t *TxStructure) Clear(key []byte) error {
if t.readWriter == nil {
return ErrWriteOnSnapshot
}
ek := t.encodeStringDataKey(key)
err := t.readWriter.Delete(ek)
if kv.ErrNotExist.Equal(err) {
err = nil
}
return errors.Trace(err)
}
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