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// This code has been inspired from https://github.com/google/shlex
//
// Copyright 2012 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// The following changes are published under the MIT license:
//
// * Internal variables renamed
// * Recording of the original argument start position in the string
// * Reformatting of some code parts.
//
// SPDX-License-Identifier: MIT
// Copyright (c) 2023 Robin Jarry
package opt
// runeClass is the type of a UTF-8 character classification: A quote, space,
// escape.
type runeClass int
const (
other runeClass = iota
space
doubleQuote
singleQuote
backslash
)
var runeClasses = map[rune]runeClass{
' ': space,
'\t': space,
'\r': space,
'\n': space,
'"': doubleQuote,
'\'': singleQuote,
'\\': backslash,
}
// the internal state used by the lexer state machine
type lexerState int
// Lexer state machine states
const (
// no runes have been seen
start lexerState = iota
// processing regular runes in a word
inWord
// we have just consumed an escape rune; the next rune is literal
escaping
// we have just consumed an escape rune within a quoted string
escapingQuoted
// we are within a quoted string that supports escaping ("...")
inDoubleQuote
// we are within a string that does not support escaping ('...')
inSingleQuote
)
// Each argument info contains the start offset of the raw argument in the
// command line (including shell escapes, quotes, etc.), and its "unquoted"
// value after interpreting shell quotes and escapes.
type argInfo struct {
start int
end int
unquoted string
}
// Parse a raw command line and return a list of argument info structs
func lexCmdline(raw []rune) []argInfo {
var state lexerState
var unquoted []rune
var argstart int
var infos []argInfo
state = start
for i, char := range raw {
class := runeClasses[char]
switch state {
case start:
// no runes read yet
switch class {
case space:
break
case doubleQuote:
state = inDoubleQuote
case singleQuote:
state = inSingleQuote
case backslash:
state = escaping
default:
// start a new word
unquoted = []rune{char}
state = inWord
}
argstart = i
case inWord:
switch class {
case space:
infos = append(infos, argInfo{
start: argstart,
end: i,
unquoted: string(unquoted),
})
unquoted = nil
state = start
case doubleQuote:
state = inDoubleQuote
case singleQuote:
state = inSingleQuote
case backslash:
state = escaping
default:
unquoted = append(unquoted, char)
}
case escaping:
// the rune after an escape character
state = inWord
unquoted = append(unquoted, char)
case escapingQuoted:
// the next rune after an escape character, in double quotes
state = inDoubleQuote
unquoted = append(unquoted, char)
case inDoubleQuote:
switch class {
case doubleQuote:
state = inWord
case backslash:
state = escapingQuoted
default:
unquoted = append(unquoted, char)
}
case inSingleQuote:
switch class {
case singleQuote:
state = inWord
default:
unquoted = append(unquoted, char)
}
}
}
if unquoted != nil {
infos = append(infos, argInfo{
start: argstart,
end: len(raw),
unquoted: string(unquoted),
})
}
return infos
}
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