ducky/devices

Paddy 2015-12-19 Parent:a700ede02f91

17:ad63b888f899 Go to Latest

ducky/devices/vendor/code.secondbit.org/pqarrays.hg/lexer.go

Fix JSON pointers in errors when creating devices. Our JSON pointers used to point at the root of the document, but the properties were actually in objects in an array keyed off of "devices", so we had to update the field property of our errors to match. While we were in there, we fixed the "insufficient" error for a Device's name to be "missing" when the name is an empty string. So far, the only way for a Device's name for it to be insufficient is _for it to be the empty string_, but if in the future we raise the minimum length of the Device name, there will be a distinction and I'd like the code to recognise it.

Download raw file
View source Diff to previous Annotate
History
paddy@16 1 package pqarrays
paddy@16 2
paddy@16 3 import (
paddy@16 4 "fmt"
paddy@16 5 "strings"
paddy@16 6 "unicode"
paddy@16 7 "unicode/utf8"
paddy@16 8 )
paddy@16 9
paddy@16 10 const (
paddy@16 11 eof = -1
paddy@16 12 leftDelim = "{"
paddy@16 13 rightDelim = "}"
paddy@16 14 separator = ','
paddy@16 15 )
paddy@16 16
paddy@16 17 type tokenType int
paddy@16 18
paddy@16 19 const (
paddy@16 20 tokenError tokenType = iota
paddy@16 21 tokenWhitespace
paddy@16 22 tokenArrayStart
paddy@16 23 tokenString
paddy@16 24 tokenNull
paddy@16 25 tokenSeparator
paddy@16 26 tokenArrayEnd
paddy@16 27 tokenEOF
paddy@16 28 )
paddy@16 29
paddy@16 30 func (t tokenType) String() string {
paddy@16 31 switch t {
paddy@16 32 case tokenError:
paddy@16 33 return "error"
paddy@16 34 case tokenWhitespace:
paddy@16 35 return "whitespace"
paddy@16 36 case tokenArrayStart:
paddy@16 37 return "array start"
paddy@16 38 case tokenString:
paddy@16 39 return "string"
paddy@16 40 case tokenNull:
paddy@16 41 return "null"
paddy@16 42 case tokenSeparator:
paddy@16 43 return "separator"
paddy@16 44 case tokenArrayEnd:
paddy@16 45 return "array end"
paddy@16 46 case tokenEOF:
paddy@16 47 return "eof"
paddy@16 48 default:
paddy@16 49 return "unknown token"
paddy@16 50 }
paddy@16 51 }
paddy@16 52
paddy@16 53 type stateFunc func(*lexer) stateFunc
paddy@16 54
paddy@16 55 type lexer struct {
paddy@16 56 tokens chan token
paddy@16 57 input string
paddy@16 58 start int
paddy@16 59 pos int
paddy@16 60 omitted []int
paddy@16 61 width int
paddy@16 62 state stateFunc
paddy@16 63 arrayDepth int
paddy@16 64 }
paddy@16 65
paddy@16 66 type token struct {
paddy@16 67 typ tokenType
paddy@16 68 val string
paddy@16 69 }
paddy@16 70
paddy@16 71 func lex(input string) *lexer {
paddy@16 72 l := &lexer{
paddy@16 73 input: input,
paddy@16 74 tokens: make(chan token),
paddy@16 75 }
paddy@16 76 go l.run()
paddy@16 77 return l
paddy@16 78 }
paddy@16 79
paddy@16 80 func (l *lexer) nextToken() token {
paddy@16 81 return <-l.tokens
paddy@16 82 }
paddy@16 83
paddy@16 84 func (l *lexer) run() {
paddy@16 85 for l.state = lexStart; l.state != nil; { // TODO(paddy): default state
paddy@16 86 l.state = l.state(l)
paddy@16 87 }
paddy@16 88 }
paddy@16 89
paddy@16 90 func (l *lexer) emit(t tokenType) {
paddy@16 91 var val string
paddy@16 92 if len(l.omitted) < 1 {
paddy@16 93 val = l.input[l.start:l.pos]
paddy@16 94 } else {
paddy@16 95 start := l.start
paddy@16 96 for _, pos := range l.omitted {
paddy@16 97 val += l.input[start:pos]
paddy@16 98 start = pos + 1
paddy@16 99 }
paddy@16 100 if l.pos > start {
paddy@16 101 val += l.input[start:l.pos]
paddy@16 102 }
paddy@16 103 }
paddy@16 104 l.tokens <- token{typ: t, val: val}
paddy@16 105 l.start = l.pos
paddy@16 106 l.omitted = l.omitted[0:0]
paddy@16 107 }
paddy@16 108
paddy@16 109 func (l *lexer) next() rune {
paddy@16 110 if l.pos >= len(l.input) {
paddy@16 111 l.width = 0
paddy@16 112 return eof
paddy@16 113 }
paddy@16 114 var r rune
paddy@16 115 r, l.width = utf8.DecodeRuneInString(l.input[l.pos:])
paddy@16 116 l.pos += l.width
paddy@16 117 return r
paddy@16 118 }
paddy@16 119
paddy@16 120 func (l *lexer) omit() {
paddy@16 121 l.omitted = append(l.omitted, l.pos-1)
paddy@16 122 }
paddy@16 123
paddy@16 124 func (l *lexer) ignore() {
paddy@16 125 l.start = l.pos
paddy@16 126 }
paddy@16 127
paddy@16 128 func (l *lexer) backup() {
paddy@16 129 l.pos -= l.width
paddy@16 130 }
paddy@16 131
paddy@16 132 func (l *lexer) peek() rune {
paddy@16 133 r := l.next()
paddy@16 134 l.backup()
paddy@16 135 return r
paddy@16 136 }
paddy@16 137
paddy@16 138 func (l *lexer) accept(valid string) bool {
paddy@16 139 if strings.IndexRune(valid, l.next()) >= 0 {
paddy@16 140 return true
paddy@16 141 }
paddy@16 142 l.backup()
paddy@16 143 return false
paddy@16 144 }
paddy@16 145
paddy@16 146 func (l *lexer) acceptRun(valid string) {
paddy@16 147 for strings.IndexRune(valid, l.next()) >= 0 {
paddy@16 148 }
paddy@16 149 l.backup()
paddy@16 150 }
paddy@16 151
paddy@16 152 func (l *lexer) errorf(format string, args ...interface{}) stateFunc {
paddy@16 153 l.tokens <- token{tokenError, fmt.Sprintf(format, args...)}
paddy@16 154 return nil
paddy@16 155 }
paddy@16 156
paddy@16 157 func (l *lexer) consumeWhitespace() {
paddy@16 158 for unicode.IsSpace(l.peek()) {
paddy@16 159 l.next()
paddy@16 160 }
paddy@16 161 if l.start > l.pos {
paddy@16 162 l.emit(tokenWhitespace)
paddy@16 163 }
paddy@16 164 }
paddy@16 165
paddy@16 166 func lexStart(l *lexer) stateFunc {
paddy@16 167 l.consumeWhitespace()
paddy@16 168 return lexArrayStart
paddy@16 169 }
paddy@16 170
paddy@16 171 func lexArrayStart(l *lexer) stateFunc {
paddy@16 172 if strings.HasPrefix(l.input[l.pos:], leftDelim) {
paddy@16 173 return lexLeftDelim
paddy@16 174 }
paddy@16 175 return l.errorf("expected array to start before %s", l.input[l.pos:])
paddy@16 176 }
paddy@16 177
paddy@16 178 func lexLeftDelim(l *lexer) stateFunc {
paddy@16 179 l.pos += len(leftDelim)
paddy@16 180 l.emit(tokenArrayStart)
paddy@16 181 l.arrayDepth += 1
paddy@16 182 return lexItem
paddy@16 183 }
paddy@16 184
paddy@16 185 func lexRightDelim(l *lexer) stateFunc {
paddy@16 186 l.pos += len(rightDelim)
paddy@16 187 l.emit(tokenArrayEnd)
paddy@16 188 l.arrayDepth -= 1
paddy@16 189 return lexSeparator
paddy@16 190 }
paddy@16 191
paddy@16 192 func lexItem(l *lexer) stateFunc {
paddy@16 193 l.consumeWhitespace()
paddy@16 194 if strings.HasPrefix(l.input[l.pos:], rightDelim) {
paddy@16 195 return lexRightDelim
paddy@16 196 }
paddy@16 197 if strings.HasPrefix(l.input[l.pos:], leftDelim) {
paddy@16 198 return lexLeftDelim
paddy@16 199 }
paddy@16 200 switch r := l.peek(); {
paddy@16 201 case r == eof:
paddy@16 202 return l.errorf("unclosed array")
paddy@16 203 case r == separator:
paddy@16 204 return l.errorf("empty item in array")
paddy@16 205 case unicode.IsSpace(r):
paddy@16 206 l.consumeWhitespace()
paddy@16 207 return lexItem
paddy@16 208 case r == '"':
paddy@16 209 return lexQuotedString
paddy@16 210 default:
paddy@16 211 return lexString
paddy@16 212 }
paddy@16 213 }
paddy@16 214
paddy@16 215 func lexQuotedString(l *lexer) stateFunc {
paddy@16 216 l.next()
paddy@16 217 l.ignore() // ignore the open quote
paddy@16 218 for {
paddy@16 219 switch r := l.next(); {
paddy@16 220 case r == eof:
paddy@16 221 return l.errorf("unclosed quoted string")
paddy@16 222 case r == '"':
paddy@16 223 l.backup()
paddy@16 224 l.emit(tokenString)
paddy@16 225 l.next()
paddy@16 226 l.ignore()
paddy@16 227 return lexSeparator
paddy@16 228 case r == '\\':
paddy@16 229 // omit the \ itself
paddy@16 230 l.omit()
paddy@16 231 // always skip over the character following a \
paddy@16 232 l.next()
paddy@16 233 if r == eof {
paddy@16 234 return l.errorf("unclosed quoted string")
paddy@16 235 }
paddy@16 236 }
paddy@16 237 }
paddy@16 238 }
paddy@16 239
paddy@16 240 func lexString(l *lexer) stateFunc {
paddy@16 241 for {
paddy@16 242 if strings.HasPrefix(l.input[l.pos:], leftDelim) {
paddy@16 243 return l.errorf(leftDelim + " in unquoted string")
paddy@16 244 }
paddy@16 245 if strings.HasPrefix(l.input[l.pos:], rightDelim) {
paddy@16 246 if l.pos <= l.start {
paddy@16 247 return l.errorf(rightDelim + " in unquoted string")
paddy@16 248 }
paddy@16 249 if string(l.input[l.start:l.pos]) == "NULL" {
paddy@16 250 l.emit(tokenNull)
paddy@16 251 } else {
paddy@16 252 l.emit(tokenString)
paddy@16 253 }
paddy@16 254 return lexRightDelim
paddy@16 255 }
paddy@16 256 switch r := l.next(); {
paddy@16 257 case r == eof:
paddy@16 258 return l.errorf("eof while parsing string")
paddy@16 259 case r == '"':
paddy@16 260 return l.errorf("\" in unquoted string")
paddy@16 261 case unicode.IsSpace(r):
paddy@16 262 return l.errorf("unquoted empty string")
paddy@16 263 case r == '\\':
paddy@16 264 return l.errorf("\\ in unquoted string")
paddy@16 265 case r == separator:
paddy@16 266 l.backup()
paddy@16 267 if l.pos <= l.start {
paddy@16 268 return l.errorf("unquoted empty string")
paddy@16 269 }
paddy@16 270 if string(l.input[l.start:l.pos]) == "NULL" {
paddy@16 271 l.emit(tokenNull)
paddy@16 272 } else {
paddy@16 273 l.emit(tokenString)
paddy@16 274 }
paddy@16 275 return lexSeparator
paddy@16 276 }
paddy@16 277 }
paddy@16 278 }
paddy@16 279
paddy@16 280 func lexSeparator(l *lexer) stateFunc {
paddy@16 281 if strings.HasPrefix(l.input[l.pos:], rightDelim) {
paddy@16 282 return lexRightDelim
paddy@16 283 }
paddy@16 284 r := l.next()
paddy@16 285 if r == separator {
paddy@16 286 l.emit(tokenSeparator)
paddy@16 287 return lexItem
paddy@16 288 } else if r == eof {
paddy@16 289 if l.arrayDepth > 0 {
paddy@16 290 return l.errorf("unclosed array")
paddy@16 291 }
paddy@16 292 l.emit(tokenEOF)
paddy@16 293 return nil
paddy@16 294 } else {
paddy@16 295 l.backup()
paddy@16 296 return l.errorf("expected %s, none found before %s\n", separator, l.input[l.pos:])
paddy@16 297 }
paddy@16 298 }