diff options
Diffstat (limited to 'vendor/github.com/godbus/dbus/variant_lexer.go')
-rw-r--r-- | vendor/github.com/godbus/dbus/variant_lexer.go | 284 |
1 files changed, 284 insertions, 0 deletions
diff --git a/vendor/github.com/godbus/dbus/variant_lexer.go b/vendor/github.com/godbus/dbus/variant_lexer.go new file mode 100644 index 000000000..332007d6f --- /dev/null +++ b/vendor/github.com/godbus/dbus/variant_lexer.go @@ -0,0 +1,284 @@ +package dbus + +import ( + "fmt" + "strings" + "unicode" + "unicode/utf8" +) + +// Heavily inspired by the lexer from text/template. + +type varToken struct { + typ varTokenType + val string +} + +type varTokenType byte + +const ( + tokEOF varTokenType = iota + tokError + tokNumber + tokString + tokBool + tokArrayStart + tokArrayEnd + tokDictStart + tokDictEnd + tokVariantStart + tokVariantEnd + tokComma + tokColon + tokType + tokByteString +) + +type varLexer struct { + input string + start int + pos int + width int + tokens []varToken +} + +type lexState func(*varLexer) lexState + +func varLex(s string) []varToken { + l := &varLexer{input: s} + l.run() + return l.tokens +} + +func (l *varLexer) accept(valid string) bool { + if strings.IndexRune(valid, l.next()) >= 0 { + return true + } + l.backup() + return false +} + +func (l *varLexer) backup() { + l.pos -= l.width +} + +func (l *varLexer) emit(t varTokenType) { + l.tokens = append(l.tokens, varToken{t, l.input[l.start:l.pos]}) + l.start = l.pos +} + +func (l *varLexer) errorf(format string, v ...interface{}) lexState { + l.tokens = append(l.tokens, varToken{ + tokError, + fmt.Sprintf(format, v...), + }) + return nil +} + +func (l *varLexer) ignore() { + l.start = l.pos +} + +func (l *varLexer) next() rune { + var r rune + + if l.pos >= len(l.input) { + l.width = 0 + return -1 + } + r, l.width = utf8.DecodeRuneInString(l.input[l.pos:]) + l.pos += l.width + return r +} + +func (l *varLexer) run() { + for state := varLexNormal; state != nil; { + state = state(l) + } +} + +func (l *varLexer) peek() rune { + r := l.next() + l.backup() + return r +} + +func varLexNormal(l *varLexer) lexState { + for { + r := l.next() + switch { + case r == -1: + l.emit(tokEOF) + return nil + case r == '[': + l.emit(tokArrayStart) + case r == ']': + l.emit(tokArrayEnd) + case r == '{': + l.emit(tokDictStart) + case r == '}': + l.emit(tokDictEnd) + case r == '<': + l.emit(tokVariantStart) + case r == '>': + l.emit(tokVariantEnd) + case r == ':': + l.emit(tokColon) + case r == ',': + l.emit(tokComma) + case r == '\'' || r == '"': + l.backup() + return varLexString + case r == '@': + l.backup() + return varLexType + case unicode.IsSpace(r): + l.ignore() + case unicode.IsNumber(r) || r == '+' || r == '-': + l.backup() + return varLexNumber + case r == 'b': + pos := l.start + if n := l.peek(); n == '"' || n == '\'' { + return varLexByteString + } + // not a byte string; try to parse it as a type or bool below + l.pos = pos + 1 + l.width = 1 + fallthrough + default: + // either a bool or a type. Try bools first. + l.backup() + if l.pos+4 <= len(l.input) { + if l.input[l.pos:l.pos+4] == "true" { + l.pos += 4 + l.emit(tokBool) + continue + } + } + if l.pos+5 <= len(l.input) { + if l.input[l.pos:l.pos+5] == "false" { + l.pos += 5 + l.emit(tokBool) + continue + } + } + // must be a type. + return varLexType + } + } +} + +var varTypeMap = map[string]string{ + "boolean": "b", + "byte": "y", + "int16": "n", + "uint16": "q", + "int32": "i", + "uint32": "u", + "int64": "x", + "uint64": "t", + "double": "f", + "string": "s", + "objectpath": "o", + "signature": "g", +} + +func varLexByteString(l *varLexer) lexState { + q := l.next() +Loop: + for { + switch l.next() { + case '\\': + if r := l.next(); r != -1 { + break + } + fallthrough + case -1: + return l.errorf("unterminated bytestring") + case q: + break Loop + } + } + l.emit(tokByteString) + return varLexNormal +} + +func varLexNumber(l *varLexer) lexState { + l.accept("+-") + digits := "0123456789" + if l.accept("0") { + if l.accept("x") { + digits = "0123456789abcdefABCDEF" + } else { + digits = "01234567" + } + } + for strings.IndexRune(digits, l.next()) >= 0 { + } + l.backup() + if l.accept(".") { + for strings.IndexRune(digits, l.next()) >= 0 { + } + l.backup() + } + if l.accept("eE") { + l.accept("+-") + for strings.IndexRune("0123456789", l.next()) >= 0 { + } + l.backup() + } + if r := l.peek(); unicode.IsLetter(r) { + l.next() + return l.errorf("bad number syntax: %q", l.input[l.start:l.pos]) + } + l.emit(tokNumber) + return varLexNormal +} + +func varLexString(l *varLexer) lexState { + q := l.next() +Loop: + for { + switch l.next() { + case '\\': + if r := l.next(); r != -1 { + break + } + fallthrough + case -1: + return l.errorf("unterminated string") + case q: + break Loop + } + } + l.emit(tokString) + return varLexNormal +} + +func varLexType(l *varLexer) lexState { + at := l.accept("@") + for { + r := l.next() + if r == -1 { + break + } + if unicode.IsSpace(r) { + l.backup() + break + } + } + if at { + if _, err := ParseSignature(l.input[l.start+1 : l.pos]); err != nil { + return l.errorf("%s", err) + } + } else { + if _, ok := varTypeMap[l.input[l.start:l.pos]]; ok { + l.emit(tokType) + return varLexNormal + } + return l.errorf("unrecognized type %q", l.input[l.start:l.pos]) + } + l.emit(tokType) + return varLexNormal +} |