mirror of
https://github.com/prometheus/node_exporter.git
synced 2024-12-23 00:46:08 +01:00
33f99c4fc1
Uses godep to vendor dependencies. Godeps is not necessary during build, golang's new vendor support is used instead.
285 lines
4.8 KiB
Go
285 lines
4.8 KiB
Go
package dbus
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import (
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"fmt"
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"strings"
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"unicode"
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"unicode/utf8"
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)
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// Heavily inspired by the lexer from text/template.
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type varToken struct {
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typ varTokenType
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val string
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}
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type varTokenType byte
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const (
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tokEOF varTokenType = iota
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tokError
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tokNumber
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tokString
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tokBool
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tokArrayStart
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tokArrayEnd
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tokDictStart
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tokDictEnd
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tokVariantStart
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tokVariantEnd
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tokComma
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tokColon
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tokType
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tokByteString
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)
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type varLexer struct {
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input string
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start int
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pos int
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width int
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tokens []varToken
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}
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type lexState func(*varLexer) lexState
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func varLex(s string) []varToken {
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l := &varLexer{input: s}
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l.run()
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return l.tokens
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}
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func (l *varLexer) accept(valid string) bool {
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if strings.IndexRune(valid, l.next()) >= 0 {
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return true
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}
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l.backup()
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return false
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}
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func (l *varLexer) backup() {
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l.pos -= l.width
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}
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func (l *varLexer) emit(t varTokenType) {
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l.tokens = append(l.tokens, varToken{t, l.input[l.start:l.pos]})
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l.start = l.pos
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}
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func (l *varLexer) errorf(format string, v ...interface{}) lexState {
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l.tokens = append(l.tokens, varToken{
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tokError,
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fmt.Sprintf(format, v...),
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})
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return nil
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}
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func (l *varLexer) ignore() {
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l.start = l.pos
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}
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func (l *varLexer) next() rune {
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var r rune
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if l.pos >= len(l.input) {
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l.width = 0
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return -1
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}
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r, l.width = utf8.DecodeRuneInString(l.input[l.pos:])
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l.pos += l.width
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return r
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}
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func (l *varLexer) run() {
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for state := varLexNormal; state != nil; {
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state = state(l)
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}
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}
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func (l *varLexer) peek() rune {
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r := l.next()
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l.backup()
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return r
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}
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func varLexNormal(l *varLexer) lexState {
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for {
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r := l.next()
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switch {
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case r == -1:
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l.emit(tokEOF)
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return nil
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case r == '[':
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l.emit(tokArrayStart)
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case r == ']':
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l.emit(tokArrayEnd)
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case r == '{':
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l.emit(tokDictStart)
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case r == '}':
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l.emit(tokDictEnd)
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case r == '<':
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l.emit(tokVariantStart)
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case r == '>':
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l.emit(tokVariantEnd)
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case r == ':':
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l.emit(tokColon)
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case r == ',':
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l.emit(tokComma)
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case r == '\'' || r == '"':
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l.backup()
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return varLexString
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case r == '@':
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l.backup()
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return varLexType
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case unicode.IsSpace(r):
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l.ignore()
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case unicode.IsNumber(r) || r == '+' || r == '-':
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l.backup()
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return varLexNumber
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case r == 'b':
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pos := l.start
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if n := l.peek(); n == '"' || n == '\'' {
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return varLexByteString
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}
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// not a byte string; try to parse it as a type or bool below
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l.pos = pos + 1
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l.width = 1
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fallthrough
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default:
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// either a bool or a type. Try bools first.
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l.backup()
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if l.pos+4 <= len(l.input) {
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if l.input[l.pos:l.pos+4] == "true" {
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l.pos += 4
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l.emit(tokBool)
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continue
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}
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}
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if l.pos+5 <= len(l.input) {
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if l.input[l.pos:l.pos+5] == "false" {
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l.pos += 5
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l.emit(tokBool)
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continue
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}
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}
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// must be a type.
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return varLexType
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}
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}
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}
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var varTypeMap = map[string]string{
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"boolean": "b",
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"byte": "y",
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"int16": "n",
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"uint16": "q",
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"int32": "i",
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"uint32": "u",
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"int64": "x",
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"uint64": "t",
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"double": "f",
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"string": "s",
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"objectpath": "o",
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"signature": "g",
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}
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func varLexByteString(l *varLexer) lexState {
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q := l.next()
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Loop:
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for {
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switch l.next() {
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case '\\':
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if r := l.next(); r != -1 {
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break
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}
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fallthrough
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case -1:
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return l.errorf("unterminated bytestring")
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case q:
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break Loop
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}
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}
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l.emit(tokByteString)
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return varLexNormal
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}
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func varLexNumber(l *varLexer) lexState {
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l.accept("+-")
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digits := "0123456789"
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if l.accept("0") {
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if l.accept("x") {
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digits = "0123456789abcdefABCDEF"
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} else {
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digits = "01234567"
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}
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}
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for strings.IndexRune(digits, l.next()) >= 0 {
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}
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l.backup()
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if l.accept(".") {
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for strings.IndexRune(digits, l.next()) >= 0 {
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}
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l.backup()
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}
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if l.accept("eE") {
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l.accept("+-")
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for strings.IndexRune("0123456789", l.next()) >= 0 {
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}
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l.backup()
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}
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if r := l.peek(); unicode.IsLetter(r) {
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l.next()
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return l.errorf("bad number syntax: %q", l.input[l.start:l.pos])
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}
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l.emit(tokNumber)
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return varLexNormal
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}
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func varLexString(l *varLexer) lexState {
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q := l.next()
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Loop:
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for {
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switch l.next() {
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case '\\':
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if r := l.next(); r != -1 {
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break
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}
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fallthrough
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case -1:
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return l.errorf("unterminated string")
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case q:
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break Loop
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}
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}
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l.emit(tokString)
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return varLexNormal
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}
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func varLexType(l *varLexer) lexState {
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at := l.accept("@")
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for {
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r := l.next()
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if r == -1 {
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break
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}
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if unicode.IsSpace(r) {
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l.backup()
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break
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}
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}
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if at {
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if _, err := ParseSignature(l.input[l.start+1 : l.pos]); err != nil {
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return l.errorf("%s", err)
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}
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} else {
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if _, ok := varTypeMap[l.input[l.start:l.pos]]; ok {
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l.emit(tokType)
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return varLexNormal
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}
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return l.errorf("unrecognized type %q", l.input[l.start:l.pos])
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}
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l.emit(tokType)
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return varLexNormal
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}
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