You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
gitea/vendor/github.com/pingcap/tidb/kv/memdb_buffer.go

107 lines
2.5 KiB

// Copyright 2015 PingCAP, Inc.
//
// Copyright 2015 Wenbin Xiao
//
// 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,
// See the License for the specific language governing permissions and
// limitations under the License.
package kv
import (
"github.com/juju/errors"
"github.com/pingcap/tidb/terror"
"github.com/syndtr/goleveldb/leveldb"
"github.com/syndtr/goleveldb/leveldb/comparer"
"github.com/syndtr/goleveldb/leveldb/iterator"
"github.com/syndtr/goleveldb/leveldb/memdb"
"github.com/syndtr/goleveldb/leveldb/util"
)
type memDbBuffer struct {
db *memdb.DB
}
type memDbIter struct {
iter iterator.Iterator
}
// NewMemDbBuffer creates a new memDbBuffer.
func NewMemDbBuffer() MemBuffer {
return &memDbBuffer{db: memdb.New(comparer.DefaultComparer, 4*1024)}
}
// Seek creates an Iterator.
func (m *memDbBuffer) Seek(k Key) (Iterator, error) {
var i Iterator
if k == nil {
i = &memDbIter{iter: m.db.NewIterator(&util.Range{})}
} else {
i = &memDbIter{iter: m.db.NewIterator(&util.Range{Start: []byte(k)})}
}
i.Next()
return i, nil
}
// Get returns the value associated with key.
func (m *memDbBuffer) Get(k Key) ([]byte, error) {
v, err := m.db.Get(k)
if terror.ErrorEqual(err, leveldb.ErrNotFound) {
return nil, ErrNotExist
}
return v, nil
}
// Set associates key with value.
func (m *memDbBuffer) Set(k Key, v []byte) error {
if len(v) == 0 {
return errors.Trace(ErrCannotSetNilValue)
}
err := m.db.Put(k, v)
return errors.Trace(err)
}
// Delete removes the entry from buffer with provided key.
func (m *memDbBuffer) Delete(k Key) error {
err := m.db.Put(k, nil)
return errors.Trace(err)
}
// Release reset the buffer.
func (m *memDbBuffer) Release() {
m.db.Reset()
}
// Next implements the Iterator Next.
func (i *memDbIter) Next() error {
i.iter.Next()
return nil
}
// Valid implements the Iterator Valid.
func (i *memDbIter) Valid() bool {
return i.iter.Valid()
}
// Key implements the Iterator Key.
func (i *memDbIter) Key() Key {
return i.iter.Key()
}
// Value implements the Iterator Value.
func (i *memDbIter) Value() []byte {
return i.iter.Value()
}
// Close Implements the Iterator Close.
func (i *memDbIter) Close() {
i.iter.Release()
}