1 files changed, 521 insertions, 0 deletions
diff --git a/vendor/github.com/vincent-petithory/dataurl/lex.go b/vendor/github.com/vincent-petithory/dataurl/lex.go
new file mode 100644
index 00000000..1a8717f5
--- /dev/null
+++ b/vendor/github.com/vincent-petithory/dataurl/lex.go
@@ -0,0 +1,521 @@
+package dataurl
+
+import (
+	"fmt"
+	"strings"
+	"unicode"
+	"unicode/utf8"
+)
+
+type item struct {
+	t   itemType
+	val string
+}
+
+func (i item) String() string {
+	switch i.t {
+	case itemEOF:
+		return "EOF"
+	case itemError:
+		return i.val
+	}
+	if len(i.val) > 10 {
+		return fmt.Sprintf("%.10q...", i.val)
+	}
+	return fmt.Sprintf("%q", i.val)
+}
+
+type itemType int
+
+const (
+	itemError itemType = iota
+	itemEOF
+
+	itemDataPrefix
+
+	itemMediaType
+	itemMediaSep
+	itemMediaSubType
+	itemParamSemicolon
+	itemParamAttr
+	itemParamEqual
+	itemLeftStringQuote
+	itemRightStringQuote
+	itemParamVal
+
+	itemBase64Enc
+
+	itemDataComma
+	itemData
+)
+
+const eof rune = -1
+
+func isTokenRune(r rune) bool {
+	return r <= unicode.MaxASCII &&
+		!unicode.IsControl(r) &&
+		!unicode.IsSpace(r) &&
+		!isTSpecialRune(r)
+}
+
+func isTSpecialRune(r rune) bool {
+	return r == '(' ||
+		r == ')' ||
+		r == '<' ||
+		r == '>' ||
+		r == '@' ||
+		r == ',' ||
+		r == ';' ||
+		r == ':' ||
+		r == '\\' ||
+		r == '"' ||
+		r == '/' ||
+		r == '[' ||
+		r == ']' ||
+		r == '?' ||
+		r == '='
+}
+
+// See http://tools.ietf.org/html/rfc2045
+// This doesn't include extension-token case
+// as it's handled separatly
+func isDiscreteType(s string) bool {
+	if strings.HasPrefix(s, "text") ||
+		strings.HasPrefix(s, "image") ||
+		strings.HasPrefix(s, "audio") ||
+		strings.HasPrefix(s, "video") ||
+		strings.HasPrefix(s, "application") {
+		return true
+	}
+	return false
+}
+
+// See http://tools.ietf.org/html/rfc2045
+// This doesn't include extension-token case
+// as it's handled separatly
+func isCompositeType(s string) bool {
+	if strings.HasPrefix(s, "message") ||
+		strings.HasPrefix(s, "multipart") {
+		return true
+	}
+	return false
+}
+
+func isURLCharRune(r rune) bool {
+	// We're a bit permissive here,
+	// by not including '%' in delims
+	// This is okay, since url unescaping will validate
+	// that later in the parser.
+	return r <= unicode.MaxASCII &&
+		!(r >= 0x00 && r <= 0x1F) && r != 0x7F && /* control */
+		// delims
+		r != ' ' &&
+		r != '<' &&
+		r != '>' &&
+		r != '#' &&
+		r != '"' &&
+		// unwise
+		r != '{' &&
+		r != '}' &&
+		r != '|' &&
+		r != '\\' &&
+		r != '^' &&
+		r != '[' &&
+		r != ']' &&
+		r != '`'
+}
+
+func isBase64Rune(r rune) bool {
+	return (r >= 'a' && r <= 'z') ||
+		(r >= 'A' && r <= 'Z') ||
+		(r >= '0' && r <= '9') ||
+		r == '+' ||
+		r == '/' ||
+		r == '=' ||
+		r == '\n'
+}
+
+type stateFn func(*lexer) stateFn
+
+// lexer lexes the data URL scheme input string.
+// The implementation is from the text/template/parser package.
+type lexer struct {
+	input          string
+	start          int
+	pos            int
+	width          int
+	seenBase64Item bool
+	items          chan item
+}
+
+func (l *lexer) run() {
+	for state := lexBeforeDataPrefix; state != nil; {
+		state = state(l)
+	}
+	close(l.items)
+}
+
+func (l *lexer) emit(t itemType) {
+	l.items <- item{t, l.input[l.start:l.pos]}
+	l.start = l.pos
+}
+
+func (l *lexer) next() (r rune) {
+	if l.pos >= len(l.input) {
+		l.width = 0
+		return eof
+	}
+	r, l.width = utf8.DecodeRuneInString(l.input[l.pos:])
+	l.pos += l.width
+	return r
+}
+
+func (l *lexer) backup() {
+	l.pos -= l.width
+}
+
+func (l *lexer) ignore() {
+	l.start = l.pos
+}
+
+func (l *lexer) errorf(format string, args ...interface{}) stateFn {
+	l.items <- item{itemError, fmt.Sprintf(format, args...)}
+	return nil
+}
+
+func lex(input string) *lexer {
+	l := &lexer{
+		input: input,
+		items: make(chan item),
+	}
+	go l.run() // Concurrently run state machine.
+	return l
+}
+
+const (
+	dataPrefix     = "data:"
+	mediaSep       = '/'
+	paramSemicolon = ';'
+	paramEqual     = '='
+	dataComma      = ','
+)
+
+// start lexing by detecting data prefix
+func lexBeforeDataPrefix(l *lexer) stateFn {
+	if strings.HasPrefix(l.input[l.pos:], dataPrefix) {
+		return lexDataPrefix
+	}
+	return l.errorf("missing data prefix")
+}
+
+// lex data prefix
+func lexDataPrefix(l *lexer) stateFn {
+	l.pos += len(dataPrefix)
+	l.emit(itemDataPrefix)
+	return lexAfterDataPrefix
+}
+
+// lex what's after data prefix.
+// it can be the media type/subtype separator,
+// the base64 encoding, or the comma preceding the data
+func lexAfterDataPrefix(l *lexer) stateFn {
+	switch r := l.next(); {
+	case r == paramSemicolon:
+		l.backup()
+		return lexParamSemicolon
+	case r == dataComma:
+		l.backup()
+		return lexDataComma
+	case r == eof:
+		return l.errorf("missing comma before data")
+	case r == 'x' || r == 'X':
+		if l.next() == '-' {
+			return lexXTokenMediaType
+		}
+		return lexInDiscreteMediaType
+	case isTokenRune(r):
+		return lexInDiscreteMediaType
+	default:
+		return l.errorf("invalid character after data prefix")
+	}
+}
+
+func lexXTokenMediaType(l *lexer) stateFn {
+	for {
+		switch r := l.next(); {
+		case r == mediaSep:
+			l.backup()
+			return lexMediaType
+		case r == eof:
+			return l.errorf("missing media type slash")
+		case isTokenRune(r):
+		default:
+			return l.errorf("invalid character for media type")
+		}
+	}
+}
+
+func lexInDiscreteMediaType(l *lexer) stateFn {
+	for {
+		switch r := l.next(); {
+		case r == mediaSep:
+			l.backup()
+			// check it's valid discrete type
+			if !isDiscreteType(l.input[l.start:l.pos]) &&
+				!isCompositeType(l.input[l.start:l.pos]) {
+				return l.errorf("invalid media type")
+			}
+			return lexMediaType
+		case r == eof:
+			return l.errorf("missing media type slash")
+		case isTokenRune(r):
+		default:
+			return l.errorf("invalid character for media type")
+		}
+	}
+}
+
+func lexMediaType(l *lexer) stateFn {
+	if l.pos > l.start {
+		l.emit(itemMediaType)
+	}
+	return lexMediaSep
+}
+
+func lexMediaSep(l *lexer) stateFn {
+	l.next()
+	l.emit(itemMediaSep)
+	return lexAfterMediaSep
+}
+
+func lexAfterMediaSep(l *lexer) stateFn {
+	for {
+		switch r := l.next(); {
+		case r == paramSemicolon || r == dataComma:
+			l.backup()
+			return lexMediaSubType
+		case r == eof:
+			return l.errorf("incomplete media type")
+		case isTokenRune(r):
+		default:
+			return l.errorf("invalid character for media subtype")
+		}
+	}
+}
+
+func lexMediaSubType(l *lexer) stateFn {
+	if l.pos > l.start {
+		l.emit(itemMediaSubType)
+	}
+	return lexAfterMediaSubType
+}
+
+func lexAfterMediaSubType(l *lexer) stateFn {
+	switch r := l.next(); {
+	case r == paramSemicolon:
+		l.backup()
+		return lexParamSemicolon
+	case r == dataComma:
+		l.backup()
+		return lexDataComma
+	case r == eof:
+		return l.errorf("missing comma before data")
+	default:
+		return l.errorf("expected semicolon or comma")
+	}
+}
+
+func lexParamSemicolon(l *lexer) stateFn {
+	l.next()
+	l.emit(itemParamSemicolon)
+	return lexAfterParamSemicolon
+}
+
+func lexAfterParamSemicolon(l *lexer) stateFn {
+	switch r := l.next(); {
+	case r == eof:
+		return l.errorf("unterminated parameter sequence")
+	case r == paramEqual || r == dataComma:
+		return l.errorf("unterminated parameter sequence")
+	case isTokenRune(r):
+		l.backup()
+		return lexInParamAttr
+	default:
+		return l.errorf("invalid character for parameter attribute")
+	}
+}
+
+func lexBase64Enc(l *lexer) stateFn {
+	if l.pos > l.start {
+		if v := l.input[l.start:l.pos]; v != "base64" {
+			return l.errorf("expected base64, got %s", v)
+		}
+		l.seenBase64Item = true
+		l.emit(itemBase64Enc)
+	}
+	return lexDataComma
+}
+
+func lexInParamAttr(l *lexer) stateFn {
+	for {
+		switch r := l.next(); {
+		case r == paramEqual:
+			l.backup()
+			return lexParamAttr
+		case r == dataComma:
+			l.backup()
+			return lexBase64Enc
+		case r == eof:
+			return l.errorf("unterminated parameter sequence")
+		case isTokenRune(r):
+		default:
+			return l.errorf("invalid character for parameter attribute")
+		}
+	}
+}
+
+func lexParamAttr(l *lexer) stateFn {
+	if l.pos > l.start {
+		l.emit(itemParamAttr)
+	}
+	return lexParamEqual
+}
+
+func lexParamEqual(l *lexer) stateFn {
+	l.next()
+	l.emit(itemParamEqual)
+	return lexAfterParamEqual
+}
+
+func lexAfterParamEqual(l *lexer) stateFn {
+	switch r := l.next(); {
+	case r == '"':
+		l.emit(itemLeftStringQuote)
+		return lexInQuotedStringParamVal
+	case r == eof:
+		return l.errorf("missing comma before data")
+	case isTokenRune(r):
+		return lexInParamVal
+	default:
+		return l.errorf("invalid character for parameter value")
+	}
+}
+
+func lexInQuotedStringParamVal(l *lexer) stateFn {
+	for {
+		switch r := l.next(); {
+		case r == eof:
+			return l.errorf("unclosed quoted string")
+		case r == '\\':
+			return lexEscapedChar
+		case r == '"':
+			l.backup()
+			return lexQuotedStringParamVal
+		case r <= unicode.MaxASCII:
+		default:
+			return l.errorf("invalid character for parameter value")
+		}
+	}
+}
+
+func lexEscapedChar(l *lexer) stateFn {
+	switch r := l.next(); {
+	case r <= unicode.MaxASCII:
+		return lexInQuotedStringParamVal
+	case r == eof:
+		return l.errorf("unexpected eof")
+	default:
+		return l.errorf("invalid escaped character")
+	}
+}
+
+func lexInParamVal(l *lexer) stateFn {
+	for {
+		switch r := l.next(); {
+		case r == paramSemicolon || r == dataComma:
+			l.backup()
+			return lexParamVal
+		case r == eof:
+			return l.errorf("missing comma before data")
+		case isTokenRune(r):
+		default:
+			return l.errorf("invalid character for parameter value")
+		}
+	}
+}
+
+func lexQuotedStringParamVal(l *lexer) stateFn {
+	if l.pos > l.start {
+		l.emit(itemParamVal)
+	}
+	l.next()
+	l.emit(itemRightStringQuote)
+	return lexAfterParamVal
+}
+
+func lexParamVal(l *lexer) stateFn {
+	if l.pos > l.start {
+		l.emit(itemParamVal)
+	}
+	return lexAfterParamVal
+}
+
+func lexAfterParamVal(l *lexer) stateFn {
+	switch r := l.next(); {
+	case r == paramSemicolon:
+		l.backup()
+		return lexParamSemicolon
+	case r == dataComma:
+		l.backup()
+		return lexDataComma
+	case r == eof:
+		return l.errorf("missing comma before data")
+	default:
+		return l.errorf("expected semicolon or comma")
+	}
+}
+
+func lexDataComma(l *lexer) stateFn {
+	l.next()
+	l.emit(itemDataComma)
+	if l.seenBase64Item {
+		return lexBase64Data
+	}
+	return lexData
+}
+
+func lexData(l *lexer) stateFn {
+Loop:
+	for {
+		switch r := l.next(); {
+		case r == eof:
+			break Loop
+		case isURLCharRune(r):
+		default:
+			return l.errorf("invalid data character")
+		}
+	}
+	if l.pos > l.start {
+		l.emit(itemData)
+	}
+	l.emit(itemEOF)
+	return nil
+}
+
+func lexBase64Data(l *lexer) stateFn {
+Loop:
+	for {
+		switch r := l.next(); {
+		case r == eof:
+			break Loop
+		case isBase64Rune(r):
+		default:
+			return l.errorf("invalid data character")
+		}
+	}
+	if l.pos > l.start {
+		l.emit(itemData)
+	}
+	l.emit(itemEOF)
+	return nil
+}