73 lines
1.8 KiB
Go
73 lines
1.8 KiB
Go
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// Copyright 2013 The ql Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSES/QL-LICENSE file.
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// 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 memkv
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import (
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"github.com/pingcap/tidb/util/types"
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)
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type btreeIterator interface {
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Next() (k, v []interface{}, err error)
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}
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// Temp is the interface of a memory kv storage
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type Temp interface {
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Drop() (err error)
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Get(k []interface{}) (v []interface{}, err error)
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SeekFirst() (e btreeIterator, err error)
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Set(k, v []interface{}) (err error)
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}
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// memtemp for join/groupby or any aggregation operation
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type memTemp struct {
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// memory btree
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tree *Tree
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}
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// CreateTemp returns a new empty memory kv
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func CreateTemp(asc bool) (_ Temp, err error) {
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return &memTemp{
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tree: NewTree(types.Collators[asc]),
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}, nil
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}
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func (t *memTemp) Get(k []interface{}) (v []interface{}, err error) {
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v, _ = t.tree.Get(k)
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return
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}
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func (t *memTemp) Drop() (err error) { return }
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func (t *memTemp) Set(k, v []interface{}) (err error) {
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vv, err := types.Clone(v)
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if err != nil {
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return err
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}
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t.tree.Set(append([]interface{}(nil), k...), vv.([]interface{}))
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return
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}
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func (t *memTemp) SeekFirst() (e btreeIterator, err error) {
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it, err := t.tree.SeekFirst()
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if err != nil {
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return
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}
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return it, nil
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}
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