ducky/devices
2015-12-19
ducky/devices/vendor/code.secondbit.org/pqarrays.hg/lexer.go
Validate device creation. Update our uuid package to the latest, which is now based on the GitHub fork instead of the Google Code. Also, update our api package to its latest version, which now needs the pqarrays package as a dependency. We fleshed out the validateDeviceCreation. We now pass in the scopes we have (for broad access control) and the user ID (for fine-grained access control). This helper returns the first error it encounters, though it should probably return a slice so we can return multiple errors all at once. Before we even decode the request to create a Device, let's check if the user is even logged in. If we can't ascertain that or they're not, there's no point in even consuming the memory necessary to read the request, because we know we're not going to use it anyways. Finally actually validate the devices we're creating, and return an appropriate error for each error we can get. Also, the api.CheckScopes helper function now takes the scopes passed in as a string slice, and we have an api.GetScopes helper function to retrieve the scopes associated with the request. Let's not keep parsing that. We need two new scopes to control access for device creation; ScopeImport lets users import devices in and is pretty much admin access. ScopeCreateOtherUserDevices allows a user to create Devices that are owned by another user.
1 package pqarrays
3 import (
4 "fmt"
5 "strings"
6 "unicode"
7 "unicode/utf8"
8 )
10 const (
11 eof = -1
12 leftDelim = "{"
13 rightDelim = "}"
14 separator = ','
15 )
17 type tokenType int
19 const (
20 tokenError tokenType = iota
21 tokenWhitespace
22 tokenArrayStart
23 tokenString
24 tokenNull
25 tokenSeparator
26 tokenArrayEnd
27 tokenEOF
28 )
30 func (t tokenType) String() string {
31 switch t {
32 case tokenError:
33 return "error"
34 case tokenWhitespace:
35 return "whitespace"
36 case tokenArrayStart:
37 return "array start"
38 case tokenString:
39 return "string"
40 case tokenNull:
41 return "null"
42 case tokenSeparator:
43 return "separator"
44 case tokenArrayEnd:
45 return "array end"
46 case tokenEOF:
47 return "eof"
48 default:
49 return "unknown token"
50 }
51 }
53 type stateFunc func(*lexer) stateFunc
55 type lexer struct {
56 tokens chan token
57 input string
58 start int
59 pos int
60 omitted []int
61 width int
62 state stateFunc
63 arrayDepth int
64 }
66 type token struct {
67 typ tokenType
68 val string
69 }
71 func lex(input string) *lexer {
72 l := &lexer{
73 input: input,
74 tokens: make(chan token),
75 }
76 go l.run()
77 return l
78 }
80 func (l *lexer) nextToken() token {
81 return <-l.tokens
82 }
84 func (l *lexer) run() {
85 for l.state = lexStart; l.state != nil; { // TODO(paddy): default state
86 l.state = l.state(l)
87 }
88 }
90 func (l *lexer) emit(t tokenType) {
91 var val string
92 if len(l.omitted) < 1 {
93 val = l.input[l.start:l.pos]
94 } else {
95 start := l.start
96 for _, pos := range l.omitted {
97 val += l.input[start:pos]
98 start = pos + 1
99 }
100 if l.pos > start {
101 val += l.input[start:l.pos]
102 }
103 }
104 l.tokens <- token{typ: t, val: val}
105 l.start = l.pos
106 l.omitted = l.omitted[0:0]
107 }
109 func (l *lexer) next() rune {
110 if l.pos >= len(l.input) {
111 l.width = 0
112 return eof
113 }
114 var r rune
115 r, l.width = utf8.DecodeRuneInString(l.input[l.pos:])
116 l.pos += l.width
117 return r
118 }
120 func (l *lexer) omit() {
121 l.omitted = append(l.omitted, l.pos-1)
122 }
124 func (l *lexer) ignore() {
125 l.start = l.pos
126 }
128 func (l *lexer) backup() {
129 l.pos -= l.width
130 }
132 func (l *lexer) peek() rune {
133 r := l.next()
134 l.backup()
135 return r
136 }
138 func (l *lexer) accept(valid string) bool {
139 if strings.IndexRune(valid, l.next()) >= 0 {
140 return true
141 }
142 l.backup()
143 return false
144 }
146 func (l *lexer) acceptRun(valid string) {
147 for strings.IndexRune(valid, l.next()) >= 0 {
148 }
149 l.backup()
150 }
152 func (l *lexer) errorf(format string, args ...interface{}) stateFunc {
153 l.tokens <- token{tokenError, fmt.Sprintf(format, args...)}
154 return nil
155 }
157 func (l *lexer) consumeWhitespace() {
158 for unicode.IsSpace(l.peek()) {
159 l.next()
160 }
161 if l.start > l.pos {
162 l.emit(tokenWhitespace)
163 }
164 }
166 func lexStart(l *lexer) stateFunc {
167 l.consumeWhitespace()
168 return lexArrayStart
169 }
171 func lexArrayStart(l *lexer) stateFunc {
172 if strings.HasPrefix(l.input[l.pos:], leftDelim) {
173 return lexLeftDelim
174 }
175 return l.errorf("expected array to start before %s", l.input[l.pos:])
176 }
178 func lexLeftDelim(l *lexer) stateFunc {
179 l.pos += len(leftDelim)
180 l.emit(tokenArrayStart)
181 l.arrayDepth += 1
182 return lexItem
183 }
185 func lexRightDelim(l *lexer) stateFunc {
186 l.pos += len(rightDelim)
187 l.emit(tokenArrayEnd)
188 l.arrayDepth -= 1
189 return lexSeparator
190 }
192 func lexItem(l *lexer) stateFunc {
193 l.consumeWhitespace()
194 if strings.HasPrefix(l.input[l.pos:], rightDelim) {
195 return lexRightDelim
196 }
197 if strings.HasPrefix(l.input[l.pos:], leftDelim) {
198 return lexLeftDelim
199 }
200 switch r := l.peek(); {
201 case r == eof:
202 return l.errorf("unclosed array")
203 case r == separator:
204 return l.errorf("empty item in array")
205 case unicode.IsSpace(r):
206 l.consumeWhitespace()
207 return lexItem
208 case r == '"':
209 return lexQuotedString
210 default:
211 return lexString
212 }
213 }
215 func lexQuotedString(l *lexer) stateFunc {
216 l.next()
217 l.ignore() // ignore the open quote
218 for {
219 switch r := l.next(); {
220 case r == eof:
221 return l.errorf("unclosed quoted string")
222 case r == '"':
223 l.backup()
224 l.emit(tokenString)
225 l.next()
226 l.ignore()
227 return lexSeparator
228 case r == '\\':
229 // omit the \ itself
230 l.omit()
231 // always skip over the character following a \
232 l.next()
233 if r == eof {
234 return l.errorf("unclosed quoted string")
235 }
236 }
237 }
238 }
240 func lexString(l *lexer) stateFunc {
241 for {
242 if strings.HasPrefix(l.input[l.pos:], leftDelim) {
243 return l.errorf(leftDelim + " in unquoted string")
244 }
245 if strings.HasPrefix(l.input[l.pos:], rightDelim) {
246 if l.pos <= l.start {
247 return l.errorf(rightDelim + " in unquoted string")
248 }
249 if string(l.input[l.start:l.pos]) == "NULL" {
250 l.emit(tokenNull)
251 } else {
252 l.emit(tokenString)
253 }
254 return lexRightDelim
255 }
256 switch r := l.next(); {
257 case r == eof:
258 return l.errorf("eof while parsing string")
259 case r == '"':
260 return l.errorf("\" in unquoted string")
261 case unicode.IsSpace(r):
262 return l.errorf("unquoted empty string")
263 case r == '\\':
264 return l.errorf("\\ in unquoted string")
265 case r == separator:
266 l.backup()
267 if l.pos <= l.start {
268 return l.errorf("unquoted empty string")
269 }
270 if string(l.input[l.start:l.pos]) == "NULL" {
271 l.emit(tokenNull)
272 } else {
273 l.emit(tokenString)
274 }
275 return lexSeparator
276 }
277 }
278 }
280 func lexSeparator(l *lexer) stateFunc {
281 if strings.HasPrefix(l.input[l.pos:], rightDelim) {
282 return lexRightDelim
283 }
284 r := l.next()
285 if r == separator {
286 l.emit(tokenSeparator)
287 return lexItem
288 } else if r == eof {
289 if l.arrayDepth > 0 {
290 return l.errorf("unclosed array")
291 }
292 l.emit(tokenEOF)
293 return nil
294 } else {
295 l.backup()
296 return l.errorf("expected %s, none found before %s\n", separator, l.input[l.pos:])
297 }
298 }