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Diffstat (limited to 'vendor/github.com/google/shlex/shlex.go')
-rw-r--r-- | vendor/github.com/google/shlex/shlex.go | 416 |
1 files changed, 416 insertions, 0 deletions
diff --git a/vendor/github.com/google/shlex/shlex.go b/vendor/github.com/google/shlex/shlex.go new file mode 100644 index 000000000..d98308bce --- /dev/null +++ b/vendor/github.com/google/shlex/shlex.go @@ -0,0 +1,416 @@ +/* +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. +*/ + +/* +Package shlex implements a simple lexer which splits input in to tokens using +shell-style rules for quoting and commenting. + +The basic use case uses the default ASCII lexer to split a string into sub-strings: + + shlex.Split("one \"two three\" four") -> []string{"one", "two three", "four"} + +To process a stream of strings: + + l := NewLexer(os.Stdin) + for ; token, err := l.Next(); err != nil { + // process token + } + +To access the raw token stream (which includes tokens for comments): + + t := NewTokenizer(os.Stdin) + for ; token, err := t.Next(); err != nil { + // process token + } + +*/ +package shlex + +import ( + "bufio" + "fmt" + "io" + "strings" +) + +// TokenType is a top-level token classification: A word, space, comment, unknown. +type TokenType int + +// runeTokenClass is the type of a UTF-8 character classification: A quote, space, escape. +type runeTokenClass int + +// the internal state used by the lexer state machine +type lexerState int + +// Token is a (type, value) pair representing a lexographical token. +type Token struct { + tokenType TokenType + value string +} + +// Equal reports whether tokens a, and b, are equal. +// Two tokens are equal if both their types and values are equal. A nil token can +// never be equal to another token. +func (a *Token) Equal(b *Token) bool { + if a == nil || b == nil { + return false + } + if a.tokenType != b.tokenType { + return false + } + return a.value == b.value +} + +// Named classes of UTF-8 runes +const ( + spaceRunes = " \t\r\n" + escapingQuoteRunes = `"` + nonEscapingQuoteRunes = "'" + escapeRunes = `\` + commentRunes = "#" +) + +// Classes of rune token +const ( + unknownRuneClass runeTokenClass = iota + spaceRuneClass + escapingQuoteRuneClass + nonEscapingQuoteRuneClass + escapeRuneClass + commentRuneClass + eofRuneClass +) + +// Classes of lexographic token +const ( + UnknownToken TokenType = iota + WordToken + SpaceToken + CommentToken +) + +// Lexer state machine states +const ( + startState lexerState = iota // no runes have been seen + inWordState // processing regular runes in a word + escapingState // we have just consumed an escape rune; the next rune is literal + escapingQuotedState // we have just consumed an escape rune within a quoted string + quotingEscapingState // we are within a quoted string that supports escaping ("...") + quotingState // we are within a string that does not support escaping ('...') + commentState // we are within a comment (everything following an unquoted or unescaped # +) + +// tokenClassifier is used for classifying rune characters. +type tokenClassifier map[rune]runeTokenClass + +func (typeMap tokenClassifier) addRuneClass(runes string, tokenType runeTokenClass) { + for _, runeChar := range runes { + typeMap[runeChar] = tokenType + } +} + +// newDefaultClassifier creates a new classifier for ASCII characters. +func newDefaultClassifier() tokenClassifier { + t := tokenClassifier{} + t.addRuneClass(spaceRunes, spaceRuneClass) + t.addRuneClass(escapingQuoteRunes, escapingQuoteRuneClass) + t.addRuneClass(nonEscapingQuoteRunes, nonEscapingQuoteRuneClass) + t.addRuneClass(escapeRunes, escapeRuneClass) + t.addRuneClass(commentRunes, commentRuneClass) + return t +} + +// ClassifyRune classifiees a rune +func (t tokenClassifier) ClassifyRune(runeVal rune) runeTokenClass { + return t[runeVal] +} + +// Lexer turns an input stream into a sequence of tokens. Whitespace and comments are skipped. +type Lexer Tokenizer + +// NewLexer creates a new lexer from an input stream. +func NewLexer(r io.Reader) *Lexer { + + return (*Lexer)(NewTokenizer(r)) +} + +// Next returns the next word, or an error. If there are no more words, +// the error will be io.EOF. +func (l *Lexer) Next() (string, error) { + for { + token, err := (*Tokenizer)(l).Next() + if err != nil { + return "", err + } + switch token.tokenType { + case WordToken: + return token.value, nil + case CommentToken: + // skip comments + default: + return "", fmt.Errorf("Unknown token type: %v", token.tokenType) + } + } +} + +// Tokenizer turns an input stream into a sequence of typed tokens +type Tokenizer struct { + input bufio.Reader + classifier tokenClassifier +} + +// NewTokenizer creates a new tokenizer from an input stream. +func NewTokenizer(r io.Reader) *Tokenizer { + input := bufio.NewReader(r) + classifier := newDefaultClassifier() + return &Tokenizer{ + input: *input, + classifier: classifier} +} + +// scanStream scans the stream for the next token using the internal state machine. +// It will panic if it encounters a rune which it does not know how to handle. +func (t *Tokenizer) scanStream() (*Token, error) { + state := startState + var tokenType TokenType + var value []rune + var nextRune rune + var nextRuneType runeTokenClass + var err error + + for { + nextRune, _, err = t.input.ReadRune() + nextRuneType = t.classifier.ClassifyRune(nextRune) + + if err == io.EOF { + nextRuneType = eofRuneClass + err = nil + } else if err != nil { + return nil, err + } + + switch state { + case startState: // no runes read yet + { + switch nextRuneType { + case eofRuneClass: + { + return nil, io.EOF + } + case spaceRuneClass: + { + } + case escapingQuoteRuneClass: + { + tokenType = WordToken + state = quotingEscapingState + } + case nonEscapingQuoteRuneClass: + { + tokenType = WordToken + state = quotingState + } + case escapeRuneClass: + { + tokenType = WordToken + state = escapingState + } + case commentRuneClass: + { + tokenType = CommentToken + state = commentState + } + default: + { + tokenType = WordToken + value = append(value, nextRune) + state = inWordState + } + } + } + case inWordState: // in a regular word + { + switch nextRuneType { + case eofRuneClass: + { + token := &Token{ + tokenType: tokenType, + value: string(value)} + return token, err + } + case spaceRuneClass: + { + token := &Token{ + tokenType: tokenType, + value: string(value)} + return token, err + } + case escapingQuoteRuneClass: + { + state = quotingEscapingState + } + case nonEscapingQuoteRuneClass: + { + state = quotingState + } + case escapeRuneClass: + { + state = escapingState + } + default: + { + value = append(value, nextRune) + } + } + } + case escapingState: // the rune after an escape character + { + switch nextRuneType { + case eofRuneClass: + { + err = fmt.Errorf("EOF found after escape character") + token := &Token{ + tokenType: tokenType, + value: string(value)} + return token, err + } + default: + { + state = inWordState + value = append(value, nextRune) + } + } + } + case escapingQuotedState: // the next rune after an escape character, in double quotes + { + switch nextRuneType { + case eofRuneClass: + { + err = fmt.Errorf("EOF found after escape character") + token := &Token{ + tokenType: tokenType, + value: string(value)} + return token, err + } + default: + { + state = quotingEscapingState + value = append(value, nextRune) + } + } + } + case quotingEscapingState: // in escaping double quotes + { + switch nextRuneType { + case eofRuneClass: + { + err = fmt.Errorf("EOF found when expecting closing quote") + token := &Token{ + tokenType: tokenType, + value: string(value)} + return token, err + } + case escapingQuoteRuneClass: + { + state = inWordState + } + case escapeRuneClass: + { + state = escapingQuotedState + } + default: + { + value = append(value, nextRune) + } + } + } + case quotingState: // in non-escaping single quotes + { + switch nextRuneType { + case eofRuneClass: + { + err = fmt.Errorf("EOF found when expecting closing quote") + token := &Token{ + tokenType: tokenType, + value: string(value)} + return token, err + } + case nonEscapingQuoteRuneClass: + { + state = inWordState + } + default: + { + value = append(value, nextRune) + } + } + } + case commentState: // in a comment + { + switch nextRuneType { + case eofRuneClass: + { + token := &Token{ + tokenType: tokenType, + value: string(value)} + return token, err + } + case spaceRuneClass: + { + if nextRune == '\n' { + state = startState + token := &Token{ + tokenType: tokenType, + value: string(value)} + return token, err + } else { + value = append(value, nextRune) + } + } + default: + { + value = append(value, nextRune) + } + } + } + default: + { + return nil, fmt.Errorf("Unexpected state: %v", state) + } + } + } +} + +// Next returns the next token in the stream. +func (t *Tokenizer) Next() (*Token, error) { + return t.scanStream() +} + +// Split partitions a string into a slice of strings. +func Split(s string) ([]string, error) { + l := NewLexer(strings.NewReader(s)) + subStrings := make([]string, 0) + for { + word, err := l.Next() + if err != nil { + if err == io.EOF { + return subStrings, nil + } + return subStrings, err + } + subStrings = append(subStrings, word) + } +} |