mirror of
https://github.com/cwinfo/matterbridge.git
synced 2024-11-30 01:31:36 +00:00
751 lines
14 KiB
Go
751 lines
14 KiB
Go
// TOML lexer.
|
|
//
|
|
// Written using the principles developed by Rob Pike in
|
|
// http://www.youtube.com/watch?v=HxaD_trXwRE
|
|
|
|
package toml
|
|
|
|
import (
|
|
"bytes"
|
|
"errors"
|
|
"fmt"
|
|
"regexp"
|
|
"strconv"
|
|
"strings"
|
|
)
|
|
|
|
var dateRegexp *regexp.Regexp
|
|
|
|
// Define state functions
|
|
type tomlLexStateFn func() tomlLexStateFn
|
|
|
|
// Define lexer
|
|
type tomlLexer struct {
|
|
inputIdx int
|
|
input []rune // Textual source
|
|
currentTokenStart int
|
|
currentTokenStop int
|
|
tokens []token
|
|
depth int
|
|
line int
|
|
col int
|
|
endbufferLine int
|
|
endbufferCol int
|
|
}
|
|
|
|
// Basic read operations on input
|
|
|
|
func (l *tomlLexer) read() rune {
|
|
r := l.peek()
|
|
if r == '\n' {
|
|
l.endbufferLine++
|
|
l.endbufferCol = 1
|
|
} else {
|
|
l.endbufferCol++
|
|
}
|
|
l.inputIdx++
|
|
return r
|
|
}
|
|
|
|
func (l *tomlLexer) next() rune {
|
|
r := l.read()
|
|
|
|
if r != eof {
|
|
l.currentTokenStop++
|
|
}
|
|
return r
|
|
}
|
|
|
|
func (l *tomlLexer) ignore() {
|
|
l.currentTokenStart = l.currentTokenStop
|
|
l.line = l.endbufferLine
|
|
l.col = l.endbufferCol
|
|
}
|
|
|
|
func (l *tomlLexer) skip() {
|
|
l.next()
|
|
l.ignore()
|
|
}
|
|
|
|
func (l *tomlLexer) fastForward(n int) {
|
|
for i := 0; i < n; i++ {
|
|
l.next()
|
|
}
|
|
}
|
|
|
|
func (l *tomlLexer) emitWithValue(t tokenType, value string) {
|
|
l.tokens = append(l.tokens, token{
|
|
Position: Position{l.line, l.col},
|
|
typ: t,
|
|
val: value,
|
|
})
|
|
l.ignore()
|
|
}
|
|
|
|
func (l *tomlLexer) emit(t tokenType) {
|
|
l.emitWithValue(t, string(l.input[l.currentTokenStart:l.currentTokenStop]))
|
|
}
|
|
|
|
func (l *tomlLexer) peek() rune {
|
|
if l.inputIdx >= len(l.input) {
|
|
return eof
|
|
}
|
|
return l.input[l.inputIdx]
|
|
}
|
|
|
|
func (l *tomlLexer) peekString(size int) string {
|
|
maxIdx := len(l.input)
|
|
upperIdx := l.inputIdx + size // FIXME: potential overflow
|
|
if upperIdx > maxIdx {
|
|
upperIdx = maxIdx
|
|
}
|
|
return string(l.input[l.inputIdx:upperIdx])
|
|
}
|
|
|
|
func (l *tomlLexer) follow(next string) bool {
|
|
return next == l.peekString(len(next))
|
|
}
|
|
|
|
// Error management
|
|
|
|
func (l *tomlLexer) errorf(format string, args ...interface{}) tomlLexStateFn {
|
|
l.tokens = append(l.tokens, token{
|
|
Position: Position{l.line, l.col},
|
|
typ: tokenError,
|
|
val: fmt.Sprintf(format, args...),
|
|
})
|
|
return nil
|
|
}
|
|
|
|
// State functions
|
|
|
|
func (l *tomlLexer) lexVoid() tomlLexStateFn {
|
|
for {
|
|
next := l.peek()
|
|
switch next {
|
|
case '[':
|
|
return l.lexTableKey
|
|
case '#':
|
|
return l.lexComment(l.lexVoid)
|
|
case '=':
|
|
return l.lexEqual
|
|
case '\r':
|
|
fallthrough
|
|
case '\n':
|
|
l.skip()
|
|
continue
|
|
}
|
|
|
|
if isSpace(next) {
|
|
l.skip()
|
|
}
|
|
|
|
if l.depth > 0 {
|
|
return l.lexRvalue
|
|
}
|
|
|
|
if isKeyStartChar(next) {
|
|
return l.lexKey
|
|
}
|
|
|
|
if next == eof {
|
|
l.next()
|
|
break
|
|
}
|
|
}
|
|
|
|
l.emit(tokenEOF)
|
|
return nil
|
|
}
|
|
|
|
func (l *tomlLexer) lexRvalue() tomlLexStateFn {
|
|
for {
|
|
next := l.peek()
|
|
switch next {
|
|
case '.':
|
|
return l.errorf("cannot start float with a dot")
|
|
case '=':
|
|
return l.lexEqual
|
|
case '[':
|
|
l.depth++
|
|
return l.lexLeftBracket
|
|
case ']':
|
|
l.depth--
|
|
return l.lexRightBracket
|
|
case '{':
|
|
return l.lexLeftCurlyBrace
|
|
case '}':
|
|
return l.lexRightCurlyBrace
|
|
case '#':
|
|
return l.lexComment(l.lexRvalue)
|
|
case '"':
|
|
return l.lexString
|
|
case '\'':
|
|
return l.lexLiteralString
|
|
case ',':
|
|
return l.lexComma
|
|
case '\r':
|
|
fallthrough
|
|
case '\n':
|
|
l.skip()
|
|
if l.depth == 0 {
|
|
return l.lexVoid
|
|
}
|
|
return l.lexRvalue
|
|
case '_':
|
|
return l.errorf("cannot start number with underscore")
|
|
}
|
|
|
|
if l.follow("true") {
|
|
return l.lexTrue
|
|
}
|
|
|
|
if l.follow("false") {
|
|
return l.lexFalse
|
|
}
|
|
|
|
if l.follow("inf") {
|
|
return l.lexInf
|
|
}
|
|
|
|
if l.follow("nan") {
|
|
return l.lexNan
|
|
}
|
|
|
|
if isSpace(next) {
|
|
l.skip()
|
|
continue
|
|
}
|
|
|
|
if next == eof {
|
|
l.next()
|
|
break
|
|
}
|
|
|
|
possibleDate := l.peekString(35)
|
|
dateMatch := dateRegexp.FindString(possibleDate)
|
|
if dateMatch != "" {
|
|
l.fastForward(len(dateMatch))
|
|
return l.lexDate
|
|
}
|
|
|
|
if next == '+' || next == '-' || isDigit(next) {
|
|
return l.lexNumber
|
|
}
|
|
|
|
if isAlphanumeric(next) {
|
|
return l.lexKey
|
|
}
|
|
|
|
return l.errorf("no value can start with %c", next)
|
|
}
|
|
|
|
l.emit(tokenEOF)
|
|
return nil
|
|
}
|
|
|
|
func (l *tomlLexer) lexLeftCurlyBrace() tomlLexStateFn {
|
|
l.next()
|
|
l.emit(tokenLeftCurlyBrace)
|
|
return l.lexRvalue
|
|
}
|
|
|
|
func (l *tomlLexer) lexRightCurlyBrace() tomlLexStateFn {
|
|
l.next()
|
|
l.emit(tokenRightCurlyBrace)
|
|
return l.lexRvalue
|
|
}
|
|
|
|
func (l *tomlLexer) lexDate() tomlLexStateFn {
|
|
l.emit(tokenDate)
|
|
return l.lexRvalue
|
|
}
|
|
|
|
func (l *tomlLexer) lexTrue() tomlLexStateFn {
|
|
l.fastForward(4)
|
|
l.emit(tokenTrue)
|
|
return l.lexRvalue
|
|
}
|
|
|
|
func (l *tomlLexer) lexFalse() tomlLexStateFn {
|
|
l.fastForward(5)
|
|
l.emit(tokenFalse)
|
|
return l.lexRvalue
|
|
}
|
|
|
|
func (l *tomlLexer) lexInf() tomlLexStateFn {
|
|
l.fastForward(3)
|
|
l.emit(tokenInf)
|
|
return l.lexRvalue
|
|
}
|
|
|
|
func (l *tomlLexer) lexNan() tomlLexStateFn {
|
|
l.fastForward(3)
|
|
l.emit(tokenNan)
|
|
return l.lexRvalue
|
|
}
|
|
|
|
func (l *tomlLexer) lexEqual() tomlLexStateFn {
|
|
l.next()
|
|
l.emit(tokenEqual)
|
|
return l.lexRvalue
|
|
}
|
|
|
|
func (l *tomlLexer) lexComma() tomlLexStateFn {
|
|
l.next()
|
|
l.emit(tokenComma)
|
|
return l.lexRvalue
|
|
}
|
|
|
|
// Parse the key and emits its value without escape sequences.
|
|
// bare keys, basic string keys and literal string keys are supported.
|
|
func (l *tomlLexer) lexKey() tomlLexStateFn {
|
|
growingString := ""
|
|
|
|
for r := l.peek(); isKeyChar(r) || r == '\n' || r == '\r'; r = l.peek() {
|
|
if r == '"' {
|
|
l.next()
|
|
str, err := l.lexStringAsString(`"`, false, true)
|
|
if err != nil {
|
|
return l.errorf(err.Error())
|
|
}
|
|
growingString += str
|
|
l.next()
|
|
continue
|
|
} else if r == '\'' {
|
|
l.next()
|
|
str, err := l.lexLiteralStringAsString(`'`, false)
|
|
if err != nil {
|
|
return l.errorf(err.Error())
|
|
}
|
|
growingString += str
|
|
l.next()
|
|
continue
|
|
} else if r == '\n' {
|
|
return l.errorf("keys cannot contain new lines")
|
|
} else if isSpace(r) {
|
|
break
|
|
} else if !isValidBareChar(r) {
|
|
return l.errorf("keys cannot contain %c character", r)
|
|
}
|
|
growingString += string(r)
|
|
l.next()
|
|
}
|
|
l.emitWithValue(tokenKey, growingString)
|
|
return l.lexVoid
|
|
}
|
|
|
|
func (l *tomlLexer) lexComment(previousState tomlLexStateFn) tomlLexStateFn {
|
|
return func() tomlLexStateFn {
|
|
for next := l.peek(); next != '\n' && next != eof; next = l.peek() {
|
|
if next == '\r' && l.follow("\r\n") {
|
|
break
|
|
}
|
|
l.next()
|
|
}
|
|
l.ignore()
|
|
return previousState
|
|
}
|
|
}
|
|
|
|
func (l *tomlLexer) lexLeftBracket() tomlLexStateFn {
|
|
l.next()
|
|
l.emit(tokenLeftBracket)
|
|
return l.lexRvalue
|
|
}
|
|
|
|
func (l *tomlLexer) lexLiteralStringAsString(terminator string, discardLeadingNewLine bool) (string, error) {
|
|
growingString := ""
|
|
|
|
if discardLeadingNewLine {
|
|
if l.follow("\r\n") {
|
|
l.skip()
|
|
l.skip()
|
|
} else if l.peek() == '\n' {
|
|
l.skip()
|
|
}
|
|
}
|
|
|
|
// find end of string
|
|
for {
|
|
if l.follow(terminator) {
|
|
return growingString, nil
|
|
}
|
|
|
|
next := l.peek()
|
|
if next == eof {
|
|
break
|
|
}
|
|
growingString += string(l.next())
|
|
}
|
|
|
|
return "", errors.New("unclosed string")
|
|
}
|
|
|
|
func (l *tomlLexer) lexLiteralString() tomlLexStateFn {
|
|
l.skip()
|
|
|
|
// handle special case for triple-quote
|
|
terminator := "'"
|
|
discardLeadingNewLine := false
|
|
if l.follow("''") {
|
|
l.skip()
|
|
l.skip()
|
|
terminator = "'''"
|
|
discardLeadingNewLine = true
|
|
}
|
|
|
|
str, err := l.lexLiteralStringAsString(terminator, discardLeadingNewLine)
|
|
if err != nil {
|
|
return l.errorf(err.Error())
|
|
}
|
|
|
|
l.emitWithValue(tokenString, str)
|
|
l.fastForward(len(terminator))
|
|
l.ignore()
|
|
return l.lexRvalue
|
|
}
|
|
|
|
// Lex a string and return the results as a string.
|
|
// Terminator is the substring indicating the end of the token.
|
|
// The resulting string does not include the terminator.
|
|
func (l *tomlLexer) lexStringAsString(terminator string, discardLeadingNewLine, acceptNewLines bool) (string, error) {
|
|
growingString := ""
|
|
|
|
if discardLeadingNewLine {
|
|
if l.follow("\r\n") {
|
|
l.skip()
|
|
l.skip()
|
|
} else if l.peek() == '\n' {
|
|
l.skip()
|
|
}
|
|
}
|
|
|
|
for {
|
|
if l.follow(terminator) {
|
|
return growingString, nil
|
|
}
|
|
|
|
if l.follow("\\") {
|
|
l.next()
|
|
switch l.peek() {
|
|
case '\r':
|
|
fallthrough
|
|
case '\n':
|
|
fallthrough
|
|
case '\t':
|
|
fallthrough
|
|
case ' ':
|
|
// skip all whitespace chars following backslash
|
|
for strings.ContainsRune("\r\n\t ", l.peek()) {
|
|
l.next()
|
|
}
|
|
case '"':
|
|
growingString += "\""
|
|
l.next()
|
|
case 'n':
|
|
growingString += "\n"
|
|
l.next()
|
|
case 'b':
|
|
growingString += "\b"
|
|
l.next()
|
|
case 'f':
|
|
growingString += "\f"
|
|
l.next()
|
|
case '/':
|
|
growingString += "/"
|
|
l.next()
|
|
case 't':
|
|
growingString += "\t"
|
|
l.next()
|
|
case 'r':
|
|
growingString += "\r"
|
|
l.next()
|
|
case '\\':
|
|
growingString += "\\"
|
|
l.next()
|
|
case 'u':
|
|
l.next()
|
|
code := ""
|
|
for i := 0; i < 4; i++ {
|
|
c := l.peek()
|
|
if !isHexDigit(c) {
|
|
return "", errors.New("unfinished unicode escape")
|
|
}
|
|
l.next()
|
|
code = code + string(c)
|
|
}
|
|
intcode, err := strconv.ParseInt(code, 16, 32)
|
|
if err != nil {
|
|
return "", errors.New("invalid unicode escape: \\u" + code)
|
|
}
|
|
growingString += string(rune(intcode))
|
|
case 'U':
|
|
l.next()
|
|
code := ""
|
|
for i := 0; i < 8; i++ {
|
|
c := l.peek()
|
|
if !isHexDigit(c) {
|
|
return "", errors.New("unfinished unicode escape")
|
|
}
|
|
l.next()
|
|
code = code + string(c)
|
|
}
|
|
intcode, err := strconv.ParseInt(code, 16, 64)
|
|
if err != nil {
|
|
return "", errors.New("invalid unicode escape: \\U" + code)
|
|
}
|
|
growingString += string(rune(intcode))
|
|
default:
|
|
return "", errors.New("invalid escape sequence: \\" + string(l.peek()))
|
|
}
|
|
} else {
|
|
r := l.peek()
|
|
|
|
if 0x00 <= r && r <= 0x1F && !(acceptNewLines && (r == '\n' || r == '\r')) {
|
|
return "", fmt.Errorf("unescaped control character %U", r)
|
|
}
|
|
l.next()
|
|
growingString += string(r)
|
|
}
|
|
|
|
if l.peek() == eof {
|
|
break
|
|
}
|
|
}
|
|
|
|
return "", errors.New("unclosed string")
|
|
}
|
|
|
|
func (l *tomlLexer) lexString() tomlLexStateFn {
|
|
l.skip()
|
|
|
|
// handle special case for triple-quote
|
|
terminator := `"`
|
|
discardLeadingNewLine := false
|
|
acceptNewLines := false
|
|
if l.follow(`""`) {
|
|
l.skip()
|
|
l.skip()
|
|
terminator = `"""`
|
|
discardLeadingNewLine = true
|
|
acceptNewLines = true
|
|
}
|
|
|
|
str, err := l.lexStringAsString(terminator, discardLeadingNewLine, acceptNewLines)
|
|
|
|
if err != nil {
|
|
return l.errorf(err.Error())
|
|
}
|
|
|
|
l.emitWithValue(tokenString, str)
|
|
l.fastForward(len(terminator))
|
|
l.ignore()
|
|
return l.lexRvalue
|
|
}
|
|
|
|
func (l *tomlLexer) lexTableKey() tomlLexStateFn {
|
|
l.next()
|
|
|
|
if l.peek() == '[' {
|
|
// token '[[' signifies an array of tables
|
|
l.next()
|
|
l.emit(tokenDoubleLeftBracket)
|
|
return l.lexInsideTableArrayKey
|
|
}
|
|
// vanilla table key
|
|
l.emit(tokenLeftBracket)
|
|
return l.lexInsideTableKey
|
|
}
|
|
|
|
// Parse the key till "]]", but only bare keys are supported
|
|
func (l *tomlLexer) lexInsideTableArrayKey() tomlLexStateFn {
|
|
for r := l.peek(); r != eof; r = l.peek() {
|
|
switch r {
|
|
case ']':
|
|
if l.currentTokenStop > l.currentTokenStart {
|
|
l.emit(tokenKeyGroupArray)
|
|
}
|
|
l.next()
|
|
if l.peek() != ']' {
|
|
break
|
|
}
|
|
l.next()
|
|
l.emit(tokenDoubleRightBracket)
|
|
return l.lexVoid
|
|
case '[':
|
|
return l.errorf("table array key cannot contain ']'")
|
|
default:
|
|
l.next()
|
|
}
|
|
}
|
|
return l.errorf("unclosed table array key")
|
|
}
|
|
|
|
// Parse the key till "]" but only bare keys are supported
|
|
func (l *tomlLexer) lexInsideTableKey() tomlLexStateFn {
|
|
for r := l.peek(); r != eof; r = l.peek() {
|
|
switch r {
|
|
case ']':
|
|
if l.currentTokenStop > l.currentTokenStart {
|
|
l.emit(tokenKeyGroup)
|
|
}
|
|
l.next()
|
|
l.emit(tokenRightBracket)
|
|
return l.lexVoid
|
|
case '[':
|
|
return l.errorf("table key cannot contain ']'")
|
|
default:
|
|
l.next()
|
|
}
|
|
}
|
|
return l.errorf("unclosed table key")
|
|
}
|
|
|
|
func (l *tomlLexer) lexRightBracket() tomlLexStateFn {
|
|
l.next()
|
|
l.emit(tokenRightBracket)
|
|
return l.lexRvalue
|
|
}
|
|
|
|
type validRuneFn func(r rune) bool
|
|
|
|
func isValidHexRune(r rune) bool {
|
|
return r >= 'a' && r <= 'f' ||
|
|
r >= 'A' && r <= 'F' ||
|
|
r >= '0' && r <= '9' ||
|
|
r == '_'
|
|
}
|
|
|
|
func isValidOctalRune(r rune) bool {
|
|
return r >= '0' && r <= '7' || r == '_'
|
|
}
|
|
|
|
func isValidBinaryRune(r rune) bool {
|
|
return r == '0' || r == '1' || r == '_'
|
|
}
|
|
|
|
func (l *tomlLexer) lexNumber() tomlLexStateFn {
|
|
r := l.peek()
|
|
|
|
if r == '0' {
|
|
follow := l.peekString(2)
|
|
if len(follow) == 2 {
|
|
var isValidRune validRuneFn
|
|
switch follow[1] {
|
|
case 'x':
|
|
isValidRune = isValidHexRune
|
|
case 'o':
|
|
isValidRune = isValidOctalRune
|
|
case 'b':
|
|
isValidRune = isValidBinaryRune
|
|
default:
|
|
if follow[1] >= 'a' && follow[1] <= 'z' || follow[1] >= 'A' && follow[1] <= 'Z' {
|
|
return l.errorf("unknown number base: %s. possible options are x (hex) o (octal) b (binary)", string(follow[1]))
|
|
}
|
|
}
|
|
|
|
if isValidRune != nil {
|
|
l.next()
|
|
l.next()
|
|
digitSeen := false
|
|
for {
|
|
next := l.peek()
|
|
if !isValidRune(next) {
|
|
break
|
|
}
|
|
digitSeen = true
|
|
l.next()
|
|
}
|
|
|
|
if !digitSeen {
|
|
return l.errorf("number needs at least one digit")
|
|
}
|
|
|
|
l.emit(tokenInteger)
|
|
|
|
return l.lexRvalue
|
|
}
|
|
}
|
|
}
|
|
|
|
if r == '+' || r == '-' {
|
|
l.next()
|
|
if l.follow("inf") {
|
|
return l.lexInf
|
|
}
|
|
if l.follow("nan") {
|
|
return l.lexNan
|
|
}
|
|
}
|
|
|
|
pointSeen := false
|
|
expSeen := false
|
|
digitSeen := false
|
|
for {
|
|
next := l.peek()
|
|
if next == '.' {
|
|
if pointSeen {
|
|
return l.errorf("cannot have two dots in one float")
|
|
}
|
|
l.next()
|
|
if !isDigit(l.peek()) {
|
|
return l.errorf("float cannot end with a dot")
|
|
}
|
|
pointSeen = true
|
|
} else if next == 'e' || next == 'E' {
|
|
expSeen = true
|
|
l.next()
|
|
r := l.peek()
|
|
if r == '+' || r == '-' {
|
|
l.next()
|
|
}
|
|
} else if isDigit(next) {
|
|
digitSeen = true
|
|
l.next()
|
|
} else if next == '_' {
|
|
l.next()
|
|
} else {
|
|
break
|
|
}
|
|
if pointSeen && !digitSeen {
|
|
return l.errorf("cannot start float with a dot")
|
|
}
|
|
}
|
|
|
|
if !digitSeen {
|
|
return l.errorf("no digit in that number")
|
|
}
|
|
if pointSeen || expSeen {
|
|
l.emit(tokenFloat)
|
|
} else {
|
|
l.emit(tokenInteger)
|
|
}
|
|
return l.lexRvalue
|
|
}
|
|
|
|
func (l *tomlLexer) run() {
|
|
for state := l.lexVoid; state != nil; {
|
|
state = state()
|
|
}
|
|
}
|
|
|
|
func init() {
|
|
dateRegexp = regexp.MustCompile(`^\d{1,4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}(\.\d{1,9})?(Z|[+-]\d{2}:\d{2})`)
|
|
}
|
|
|
|
// Entry point
|
|
func lexToml(inputBytes []byte) []token {
|
|
runes := bytes.Runes(inputBytes)
|
|
l := &tomlLexer{
|
|
input: runes,
|
|
tokens: make([]token, 0, 256),
|
|
line: 1,
|
|
col: 1,
|
|
endbufferLine: 1,
|
|
endbufferCol: 1,
|
|
}
|
|
l.run()
|
|
return l.tokens
|
|
}
|