54 lines
1.7 KiB
Go
54 lines
1.7 KiB
Go
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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 stringutil
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import (
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"bytes"
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"strings"
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)
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// See: https://dev.mysql.com/doc/refman/5.7/en/string-literals.html#character-escape-sequences
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const validEscapeChars = `0'"bntrz\\%_`
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// RemoveUselessBackslash removes backslashs which could be ignored in the string literal.
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// See: https://dev.mysql.com/doc/refman/5.7/en/string-literals.html
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// " Each of these sequences begins with a backslash (“\”), known as the escape character.
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// MySQL recognizes the escape sequences shown in Table 9.1, “Special Character Escape Sequences”.
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// For all other escape sequences, backslash is ignored. That is, the escaped character is
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// interpreted as if it was not escaped. For example, “\x” is just “x”. These sequences are case sensitive.
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// For example, “\b” is interpreted as a backspace, but “\B” is interpreted as “B”."
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func RemoveUselessBackslash(s string) string {
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var (
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buf bytes.Buffer
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i = 0
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)
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for i < len(s)-1 {
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if s[i] != '\\' {
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buf.WriteByte(s[i])
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i++
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continue
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}
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next := s[i+1]
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if strings.IndexByte(validEscapeChars, next) != -1 {
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buf.WriteByte(s[i])
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}
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buf.WriteByte(next)
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i += 2
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}
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if i == len(s)-1 {
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buf.WriteByte(s[i])
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}
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return buf.String()
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}
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