147 lines
4.9 KiB
Go
147 lines
4.9 KiB
Go
// 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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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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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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// Copyright 2013 The Go-MySQL-Driver Authors. All rights reserved.
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//
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this file,
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// You can obtain one at http://mozilla.org/MPL/2.0/.
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// The MIT License (MIT)
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//
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// Copyright (c) 2014 wandoulabs
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// Copyright (c) 2014 siddontang
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy of
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// this software and associated documentation files (the "Software"), to deal in
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// the Software without restriction, including without limitation the rights to
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// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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// the Software, and to permit persons to whom the Software is furnished to do so,
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// subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in all
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// copies or substantial portions of the Software.
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package column
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import (
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"bytes"
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"github.com/pingcap/tidb/pkg/parser/charset"
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"github.com/pingcap/tidb/pkg/parser/mysql"
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"github.com/pingcap/tidb/pkg/util/logutil"
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"go.uber.org/zap"
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)
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// ResultEncoder encodes a column value to a byte slice.
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type ResultEncoder struct {
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encoding charset.Encoding
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// dataEncoding can be updated to match the column data charset.
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dataEncoding charset.Encoding
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buffer *bytes.Buffer
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// chsName and encoding are unchanged after the initialization from
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// session variable @@character_set_results.
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chsName string
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isBinary bool
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isNull bool
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dataIsBinary bool
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}
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// NewResultEncoder creates a new ResultEncoder.
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func NewResultEncoder(chs string) *ResultEncoder {
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return &ResultEncoder{
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chsName: chs,
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encoding: charset.FindEncodingTakeUTF8AsNoop(chs),
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buffer: &bytes.Buffer{},
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isBinary: chs == charset.CharsetBin,
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isNull: len(chs) == 0,
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}
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}
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// Clean prevent the ResultEncoder from holding too much memory.
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func (d *ResultEncoder) Clean() {
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d.buffer = nil
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}
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// UpdateDataEncoding updates the data encoding.
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func (d *ResultEncoder) UpdateDataEncoding(chsID uint16) {
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chs, _, err := charset.GetCharsetInfoByID(int(chsID))
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if err != nil {
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logutil.BgLogger().Warn("unknown charset ID", zap.Error(err))
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}
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d.dataEncoding = charset.FindEncodingTakeUTF8AsNoop(chs)
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d.dataIsBinary = chsID == mysql.BinaryDefaultCollationID
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}
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// ColumnTypeInfoCharsetID returns the charset ID for the column type info.
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func (d *ResultEncoder) ColumnTypeInfoCharsetID(info *Info) uint16 {
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// Only replace the charset when @@character_set_results is valid and
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// the target column is a non-binary string.
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charset := info.dumpCharset()
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if d.isNull || len(d.chsName) == 0 || !isStringColumnType(info.Type) {
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return charset
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}
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if charset == mysql.BinaryDefaultCollationID {
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return mysql.BinaryDefaultCollationID
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}
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return uint16(mysql.CharsetNameToID(d.chsName))
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}
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// EncodeMeta encodes bytes for meta info like column names.
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// Note that the result should be consumed immediately.
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func (d *ResultEncoder) EncodeMeta(src []byte) []byte {
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return d.EncodeWith(src, d.encoding)
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}
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// EncodeData encodes bytes for row data.
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// Note that the result should be consumed immediately.
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func (d *ResultEncoder) EncodeData(src []byte) []byte {
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// For the following cases, TiDB encodes the results with column charset
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// instead of @@character_set_results:
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// - @@character_set_result = null.
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// - @@character_set_result = binary.
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// - The column is binary type like blob, binary char/varchar.
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if d.isNull || d.isBinary || d.dataIsBinary {
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// Use the column charset to encode.
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return d.EncodeWith(src, d.dataEncoding)
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}
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return d.EncodeWith(src, d.encoding)
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}
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// EncodeWith encodes bytes with the given encoding.
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func (d *ResultEncoder) EncodeWith(src []byte, enc charset.Encoding) []byte {
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data, err := enc.Transform(d.buffer, src, charset.OpEncode)
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if err != nil {
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logutil.BgLogger().Debug("encode error", zap.Error(err))
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}
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return data
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}
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func isStringColumnType(tp byte) bool {
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switch tp {
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case mysql.TypeString, mysql.TypeVarString, mysql.TypeVarchar, mysql.TypeBit,
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mysql.TypeTinyBlob, mysql.TypeMediumBlob, mysql.TypeLongBlob, mysql.TypeBlob,
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mysql.TypeEnum, mysql.TypeSet, mysql.TypeJSON:
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return true
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case mysql.TypeTiDBVectorFloat32:
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// When passing Vector column to the SQL Client, pretend to be a non-binary String.
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return true
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}
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return false
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}
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