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