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48 lines
1.3 KiB
48 lines
1.3 KiB
8 years ago
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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 distinct
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import (
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"github.com/juju/errors"
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"github.com/pingcap/tidb/util/codec"
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"github.com/pingcap/tidb/util/types"
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)
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// CreateDistinctChecker creates a new distinct checker.
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func CreateDistinctChecker() *Checker {
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return &Checker{
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existingKeys: make(map[string]bool),
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}
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}
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// Checker stores existing keys and checks if given data is distinct.
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type Checker struct {
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existingKeys map[string]bool
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}
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// Check checks if values is distinct.
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func (d *Checker) Check(values []interface{}) (bool, error) {
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bs, err := codec.EncodeValue([]byte{}, types.MakeDatums(values...)...)
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if err != nil {
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return false, errors.Trace(err)
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}
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key := string(bs)
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_, ok := d.existingKeys[key]
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if ok {
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return false, nil
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}
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d.existingKeys[key] = true
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return true, nil
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}
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