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-rwxr-xr-xvendor/github.com/andybalholm/cascadia/LICENSE24
-rw-r--r--vendor/github.com/andybalholm/cascadia/README.md7
-rw-r--r--vendor/github.com/andybalholm/cascadia/parser.go835
-rw-r--r--vendor/github.com/andybalholm/cascadia/selector.go622
4 files changed, 1488 insertions, 0 deletions
diff --git a/vendor/github.com/andybalholm/cascadia/LICENSE b/vendor/github.com/andybalholm/cascadia/LICENSE
new file mode 100755
index 0000000..ee5ad35
--- /dev/null
+++ b/vendor/github.com/andybalholm/cascadia/LICENSE
@@ -0,0 +1,24 @@
+Copyright (c) 2011 Andy Balholm. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+ * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/vendor/github.com/andybalholm/cascadia/README.md b/vendor/github.com/andybalholm/cascadia/README.md
new file mode 100644
index 0000000..9021cb9
--- /dev/null
+++ b/vendor/github.com/andybalholm/cascadia/README.md
@@ -0,0 +1,7 @@
+# cascadia
+
+[![](https://travis-ci.org/andybalholm/cascadia.svg)](https://travis-ci.org/andybalholm/cascadia)
+
+The Cascadia package implements CSS selectors for use with the parse trees produced by the html package.
+
+To test CSS selectors without writing Go code, check out [cascadia](https://github.com/suntong/cascadia) the command line tool, a thin wrapper around this package.
diff --git a/vendor/github.com/andybalholm/cascadia/parser.go b/vendor/github.com/andybalholm/cascadia/parser.go
new file mode 100644
index 0000000..495db9c
--- /dev/null
+++ b/vendor/github.com/andybalholm/cascadia/parser.go
@@ -0,0 +1,835 @@
+// Package cascadia is an implementation of CSS selectors.
+package cascadia
+
+import (
+ "errors"
+ "fmt"
+ "regexp"
+ "strconv"
+ "strings"
+
+ "golang.org/x/net/html"
+)
+
+// a parser for CSS selectors
+type parser struct {
+ s string // the source text
+ i int // the current position
+}
+
+// parseEscape parses a backslash escape.
+func (p *parser) parseEscape() (result string, err error) {
+ if len(p.s) < p.i+2 || p.s[p.i] != '\\' {
+ return "", errors.New("invalid escape sequence")
+ }
+
+ start := p.i + 1
+ c := p.s[start]
+ switch {
+ case c == '\r' || c == '\n' || c == '\f':
+ return "", errors.New("escaped line ending outside string")
+ case hexDigit(c):
+ // unicode escape (hex)
+ var i int
+ for i = start; i < p.i+6 && i < len(p.s) && hexDigit(p.s[i]); i++ {
+ // empty
+ }
+ v, _ := strconv.ParseUint(p.s[start:i], 16, 21)
+ if len(p.s) > i {
+ switch p.s[i] {
+ case '\r':
+ i++
+ if len(p.s) > i && p.s[i] == '\n' {
+ i++
+ }
+ case ' ', '\t', '\n', '\f':
+ i++
+ }
+ }
+ p.i = i
+ return string(rune(v)), nil
+ }
+
+ // Return the literal character after the backslash.
+ result = p.s[start : start+1]
+ p.i += 2
+ return result, nil
+}
+
+func hexDigit(c byte) bool {
+ return '0' <= c && c <= '9' || 'a' <= c && c <= 'f' || 'A' <= c && c <= 'F'
+}
+
+// nameStart returns whether c can be the first character of an identifier
+// (not counting an initial hyphen, or an escape sequence).
+func nameStart(c byte) bool {
+ return 'a' <= c && c <= 'z' || 'A' <= c && c <= 'Z' || c == '_' || c > 127
+}
+
+// nameChar returns whether c can be a character within an identifier
+// (not counting an escape sequence).
+func nameChar(c byte) bool {
+ return 'a' <= c && c <= 'z' || 'A' <= c && c <= 'Z' || c == '_' || c > 127 ||
+ c == '-' || '0' <= c && c <= '9'
+}
+
+// parseIdentifier parses an identifier.
+func (p *parser) parseIdentifier() (result string, err error) {
+ startingDash := false
+ if len(p.s) > p.i && p.s[p.i] == '-' {
+ startingDash = true
+ p.i++
+ }
+
+ if len(p.s) <= p.i {
+ return "", errors.New("expected identifier, found EOF instead")
+ }
+
+ if c := p.s[p.i]; !(nameStart(c) || c == '\\') {
+ return "", fmt.Errorf("expected identifier, found %c instead", c)
+ }
+
+ result, err = p.parseName()
+ if startingDash && err == nil {
+ result = "-" + result
+ }
+ return
+}
+
+// parseName parses a name (which is like an identifier, but doesn't have
+// extra restrictions on the first character).
+func (p *parser) parseName() (result string, err error) {
+ i := p.i
+loop:
+ for i < len(p.s) {
+ c := p.s[i]
+ switch {
+ case nameChar(c):
+ start := i
+ for i < len(p.s) && nameChar(p.s[i]) {
+ i++
+ }
+ result += p.s[start:i]
+ case c == '\\':
+ p.i = i
+ val, err := p.parseEscape()
+ if err != nil {
+ return "", err
+ }
+ i = p.i
+ result += val
+ default:
+ break loop
+ }
+ }
+
+ if result == "" {
+ return "", errors.New("expected name, found EOF instead")
+ }
+
+ p.i = i
+ return result, nil
+}
+
+// parseString parses a single- or double-quoted string.
+func (p *parser) parseString() (result string, err error) {
+ i := p.i
+ if len(p.s) < i+2 {
+ return "", errors.New("expected string, found EOF instead")
+ }
+
+ quote := p.s[i]
+ i++
+
+loop:
+ for i < len(p.s) {
+ switch p.s[i] {
+ case '\\':
+ if len(p.s) > i+1 {
+ switch c := p.s[i+1]; c {
+ case '\r':
+ if len(p.s) > i+2 && p.s[i+2] == '\n' {
+ i += 3
+ continue loop
+ }
+ fallthrough
+ case '\n', '\f':
+ i += 2
+ continue loop
+ }
+ }
+ p.i = i
+ val, err := p.parseEscape()
+ if err != nil {
+ return "", err
+ }
+ i = p.i
+ result += val
+ case quote:
+ break loop
+ case '\r', '\n', '\f':
+ return "", errors.New("unexpected end of line in string")
+ default:
+ start := i
+ for i < len(p.s) {
+ if c := p.s[i]; c == quote || c == '\\' || c == '\r' || c == '\n' || c == '\f' {
+ break
+ }
+ i++
+ }
+ result += p.s[start:i]
+ }
+ }
+
+ if i >= len(p.s) {
+ return "", errors.New("EOF in string")
+ }
+
+ // Consume the final quote.
+ i++
+
+ p.i = i
+ return result, nil
+}
+
+// parseRegex parses a regular expression; the end is defined by encountering an
+// unmatched closing ')' or ']' which is not consumed
+func (p *parser) parseRegex() (rx *regexp.Regexp, err error) {
+ i := p.i
+ if len(p.s) < i+2 {
+ return nil, errors.New("expected regular expression, found EOF instead")
+ }
+
+ // number of open parens or brackets;
+ // when it becomes negative, finished parsing regex
+ open := 0
+
+loop:
+ for i < len(p.s) {
+ switch p.s[i] {
+ case '(', '[':
+ open++
+ case ')', ']':
+ open--
+ if open < 0 {
+ break loop
+ }
+ }
+ i++
+ }
+
+ if i >= len(p.s) {
+ return nil, errors.New("EOF in regular expression")
+ }
+ rx, err = regexp.Compile(p.s[p.i:i])
+ p.i = i
+ return rx, err
+}
+
+// skipWhitespace consumes whitespace characters and comments.
+// It returns true if there was actually anything to skip.
+func (p *parser) skipWhitespace() bool {
+ i := p.i
+ for i < len(p.s) {
+ switch p.s[i] {
+ case ' ', '\t', '\r', '\n', '\f':
+ i++
+ continue
+ case '/':
+ if strings.HasPrefix(p.s[i:], "/*") {
+ end := strings.Index(p.s[i+len("/*"):], "*/")
+ if end != -1 {
+ i += end + len("/**/")
+ continue
+ }
+ }
+ }
+ break
+ }
+
+ if i > p.i {
+ p.i = i
+ return true
+ }
+
+ return false
+}
+
+// consumeParenthesis consumes an opening parenthesis and any following
+// whitespace. It returns true if there was actually a parenthesis to skip.
+func (p *parser) consumeParenthesis() bool {
+ if p.i < len(p.s) && p.s[p.i] == '(' {
+ p.i++
+ p.skipWhitespace()
+ return true
+ }
+ return false
+}
+
+// consumeClosingParenthesis consumes a closing parenthesis and any preceding
+// whitespace. It returns true if there was actually a parenthesis to skip.
+func (p *parser) consumeClosingParenthesis() bool {
+ i := p.i
+ p.skipWhitespace()
+ if p.i < len(p.s) && p.s[p.i] == ')' {
+ p.i++
+ return true
+ }
+ p.i = i
+ return false
+}
+
+// parseTypeSelector parses a type selector (one that matches by tag name).
+func (p *parser) parseTypeSelector() (result Selector, err error) {
+ tag, err := p.parseIdentifier()
+ if err != nil {
+ return nil, err
+ }
+
+ return typeSelector(tag), nil
+}
+
+// parseIDSelector parses a selector that matches by id attribute.
+func (p *parser) parseIDSelector() (Selector, error) {
+ if p.i >= len(p.s) {
+ return nil, fmt.Errorf("expected id selector (#id), found EOF instead")
+ }
+ if p.s[p.i] != '#' {
+ return nil, fmt.Errorf("expected id selector (#id), found '%c' instead", p.s[p.i])
+ }
+
+ p.i++
+ id, err := p.parseName()
+ if err != nil {
+ return nil, err
+ }
+
+ return attributeEqualsSelector("id", id), nil
+}
+
+// parseClassSelector parses a selector that matches by class attribute.
+func (p *parser) parseClassSelector() (Selector, error) {
+ if p.i >= len(p.s) {
+ return nil, fmt.Errorf("expected class selector (.class), found EOF instead")
+ }
+ if p.s[p.i] != '.' {
+ return nil, fmt.Errorf("expected class selector (.class), found '%c' instead", p.s[p.i])
+ }
+
+ p.i++
+ class, err := p.parseIdentifier()
+ if err != nil {
+ return nil, err
+ }
+
+ return attributeIncludesSelector("class", class), nil
+}
+
+// parseAttributeSelector parses a selector that matches by attribute value.
+func (p *parser) parseAttributeSelector() (Selector, error) {
+ if p.i >= len(p.s) {
+ return nil, fmt.Errorf("expected attribute selector ([attribute]), found EOF instead")
+ }
+ if p.s[p.i] != '[' {
+ return nil, fmt.Errorf("expected attribute selector ([attribute]), found '%c' instead", p.s[p.i])
+ }
+
+ p.i++
+ p.skipWhitespace()
+ key, err := p.parseIdentifier()
+ if err != nil {
+ return nil, err
+ }
+
+ p.skipWhitespace()
+ if p.i >= len(p.s) {
+ return nil, errors.New("unexpected EOF in attribute selector")
+ }
+
+ if p.s[p.i] == ']' {
+ p.i++
+ return attributeExistsSelector(key), nil
+ }
+
+ if p.i+2 >= len(p.s) {
+ return nil, errors.New("unexpected EOF in attribute selector")
+ }
+
+ op := p.s[p.i : p.i+2]
+ if op[0] == '=' {
+ op = "="
+ } else if op[1] != '=' {
+ return nil, fmt.Errorf(`expected equality operator, found "%s" instead`, op)
+ }
+ p.i += len(op)
+
+ p.skipWhitespace()
+ if p.i >= len(p.s) {
+ return nil, errors.New("unexpected EOF in attribute selector")
+ }
+ var val string
+ var rx *regexp.Regexp
+ if op == "#=" {
+ rx, err = p.parseRegex()
+ } else {
+ switch p.s[p.i] {
+ case '\'', '"':
+ val, err = p.parseString()
+ default:
+ val, err = p.parseIdentifier()
+ }
+ }
+ if err != nil {
+ return nil, err
+ }
+
+ p.skipWhitespace()
+ if p.i >= len(p.s) {
+ return nil, errors.New("unexpected EOF in attribute selector")
+ }
+ if p.s[p.i] != ']' {
+ return nil, fmt.Errorf("expected ']', found '%c' instead", p.s[p.i])
+ }
+ p.i++
+
+ switch op {
+ case "=":
+ return attributeEqualsSelector(key, val), nil
+ case "!=":
+ return attributeNotEqualSelector(key, val), nil
+ case "~=":
+ return attributeIncludesSelector(key, val), nil
+ case "|=":
+ return attributeDashmatchSelector(key, val), nil
+ case "^=":
+ return attributePrefixSelector(key, val), nil
+ case "$=":
+ return attributeSuffixSelector(key, val), nil
+ case "*=":
+ return attributeSubstringSelector(key, val), nil
+ case "#=":
+ return attributeRegexSelector(key, rx), nil
+ }
+
+ return nil, fmt.Errorf("attribute operator %q is not supported", op)
+}
+
+var errExpectedParenthesis = errors.New("expected '(' but didn't find it")
+var errExpectedClosingParenthesis = errors.New("expected ')' but didn't find it")
+var errUnmatchedParenthesis = errors.New("unmatched '('")
+
+// parsePseudoclassSelector parses a pseudoclass selector like :not(p).
+func (p *parser) parsePseudoclassSelector() (Selector, error) {
+ if p.i >= len(p.s) {
+ return nil, fmt.Errorf("expected pseudoclass selector (:pseudoclass), found EOF instead")
+ }
+ if p.s[p.i] != ':' {
+ return nil, fmt.Errorf("expected attribute selector (:pseudoclass), found '%c' instead", p.s[p.i])
+ }
+
+ p.i++
+ name, err := p.parseIdentifier()
+ if err != nil {
+ return nil, err
+ }
+ name = toLowerASCII(name)
+
+ switch name {
+ case "not", "has", "haschild":
+ if !p.consumeParenthesis() {
+ return nil, errExpectedParenthesis
+ }
+ sel, parseErr := p.parseSelectorGroup()
+ if parseErr != nil {
+ return nil, parseErr
+ }
+ if !p.consumeClosingParenthesis() {
+ return nil, errExpectedClosingParenthesis
+ }
+
+ switch name {
+ case "not":
+ return negatedSelector(sel), nil
+ case "has":
+ return hasDescendantSelector(sel), nil
+ case "haschild":
+ return hasChildSelector(sel), nil
+ }
+
+ case "contains", "containsown":
+ if !p.consumeParenthesis() {
+ return nil, errExpectedParenthesis
+ }
+ if p.i == len(p.s) {
+ return nil, errUnmatchedParenthesis
+ }
+ var val string
+ switch p.s[p.i] {
+ case '\'', '"':
+ val, err = p.parseString()
+ default:
+ val, err = p.parseIdentifier()
+ }
+ if err != nil {
+ return nil, err
+ }
+ val = strings.ToLower(val)
+ p.skipWhitespace()
+ if p.i >= len(p.s) {
+ return nil, errors.New("unexpected EOF in pseudo selector")
+ }
+ if !p.consumeClosingParenthesis() {
+ return nil, errExpectedClosingParenthesis
+ }
+
+ switch name {
+ case "contains":
+ return textSubstrSelector(val), nil
+ case "containsown":
+ return ownTextSubstrSelector(val), nil
+ }
+
+ case "matches", "matchesown":
+ if !p.consumeParenthesis() {
+ return nil, errExpectedParenthesis
+ }
+ rx, err := p.parseRegex()
+ if err != nil {
+ return nil, err
+ }
+ if p.i >= len(p.s) {
+ return nil, errors.New("unexpected EOF in pseudo selector")
+ }
+ if !p.consumeClosingParenthesis() {
+ return nil, errExpectedClosingParenthesis
+ }
+
+ switch name {
+ case "matches":
+ return textRegexSelector(rx), nil
+ case "matchesown":
+ return ownTextRegexSelector(rx), nil
+ }
+
+ case "nth-child", "nth-last-child", "nth-of-type", "nth-last-of-type":
+ if !p.consumeParenthesis() {
+ return nil, errExpectedParenthesis
+ }
+ a, b, err := p.parseNth()
+ if err != nil {
+ return nil, err
+ }
+ if !p.consumeClosingParenthesis() {
+ return nil, errExpectedClosingParenthesis
+ }
+ if a == 0 {
+ switch name {
+ case "nth-child":
+ return simpleNthChildSelector(b, false), nil
+ case "nth-of-type":
+ return simpleNthChildSelector(b, true), nil
+ case "nth-last-child":
+ return simpleNthLastChildSelector(b, false), nil
+ case "nth-last-of-type":
+ return simpleNthLastChildSelector(b, true), nil
+ }
+ }
+ return nthChildSelector(a, b,
+ name == "nth-last-child" || name == "nth-last-of-type",
+ name == "nth-of-type" || name == "nth-last-of-type"),
+ nil
+
+ case "first-child":
+ return simpleNthChildSelector(1, false), nil
+ case "last-child":
+ return simpleNthLastChildSelector(1, false), nil
+ case "first-of-type":
+ return simpleNthChildSelector(1, true), nil
+ case "last-of-type":
+ return simpleNthLastChildSelector(1, true), nil
+ case "only-child":
+ return onlyChildSelector(false), nil
+ case "only-of-type":
+ return onlyChildSelector(true), nil
+ case "input":
+ return inputSelector, nil
+ case "empty":
+ return emptyElementSelector, nil
+ case "root":
+ return rootSelector, nil
+ }
+
+ return nil, fmt.Errorf("unknown pseudoclass :%s", name)
+}
+
+// parseInteger parses a decimal integer.
+func (p *parser) parseInteger() (int, error) {
+ i := p.i
+ start := i
+ for i < len(p.s) && '0' <= p.s[i] && p.s[i] <= '9' {
+ i++
+ }
+ if i == start {
+ return 0, errors.New("expected integer, but didn't find it")
+ }
+ p.i = i
+
+ val, err := strconv.Atoi(p.s[start:i])
+ if err != nil {
+ return 0, err
+ }
+
+ return val, nil
+}
+
+// parseNth parses the argument for :nth-child (normally of the form an+b).
+func (p *parser) parseNth() (a, b int, err error) {
+ // initial state
+ if p.i >= len(p.s) {
+ goto eof
+ }
+ switch p.s[p.i] {
+ case '-':
+ p.i++
+ goto negativeA
+ case '+':
+ p.i++
+ goto positiveA
+ case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
+ goto positiveA
+ case 'n', 'N':
+ a = 1
+ p.i++
+ goto readN
+ case 'o', 'O', 'e', 'E':
+ id, nameErr := p.parseName()
+ if nameErr != nil {
+ return 0, 0, nameErr
+ }
+ id = toLowerASCII(id)
+ if id == "odd" {
+ return 2, 1, nil
+ }
+ if id == "even" {
+ return 2, 0, nil
+ }
+ return 0, 0, fmt.Errorf("expected 'odd' or 'even', but found '%s' instead", id)
+ default:
+ goto invalid
+ }
+
+positiveA:
+ if p.i >= len(p.s) {
+ goto eof
+ }
+ switch p.s[p.i] {
+ case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
+ a, err = p.parseInteger()
+ if err != nil {
+ return 0, 0, err
+ }
+ goto readA
+ case 'n', 'N':
+ a = 1
+ p.i++
+ goto readN
+ default:
+ goto invalid
+ }
+
+negativeA:
+ if p.i >= len(p.s) {
+ goto eof
+ }
+ switch p.s[p.i] {
+ case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
+ a, err = p.parseInteger()
+ if err != nil {
+ return 0, 0, err
+ }
+ a = -a
+ goto readA
+ case 'n', 'N':
+ a = -1
+ p.i++
+ goto readN
+ default:
+ goto invalid
+ }
+
+readA:
+ if p.i >= len(p.s) {
+ goto eof
+ }
+ switch p.s[p.i] {
+ case 'n', 'N':
+ p.i++
+ goto readN
+ default:
+ // The number we read as a is actually b.
+ return 0, a, nil
+ }
+
+readN:
+ p.skipWhitespace()
+ if p.i >= len(p.s) {
+ goto eof
+ }
+ switch p.s[p.i] {
+ case '+':
+ p.i++
+ p.skipWhitespace()
+ b, err = p.parseInteger()
+ if err != nil {
+ return 0, 0, err
+ }
+ return a, b, nil
+ case '-':
+ p.i++
+ p.skipWhitespace()
+ b, err = p.parseInteger()
+ if err != nil {
+ return 0, 0, err
+ }
+ return a, -b, nil
+ default:
+ return a, 0, nil
+ }
+
+eof:
+ return 0, 0, errors.New("unexpected EOF while attempting to parse expression of form an+b")
+
+invalid:
+ return 0, 0, errors.New("unexpected character while attempting to parse expression of form an+b")
+}
+
+// parseSimpleSelectorSequence parses a selector sequence that applies to
+// a single element.
+func (p *parser) parseSimpleSelectorSequence() (Selector, error) {
+ var result Selector
+
+ if p.i >= len(p.s) {
+ return nil, errors.New("expected selector, found EOF instead")
+ }
+
+ switch p.s[p.i] {
+ case '*':
+ // It's the universal selector. Just skip over it, since it doesn't affect the meaning.
+ p.i++
+ case '#', '.', '[', ':':
+ // There's no type selector. Wait to process the other till the main loop.
+ default:
+ r, err := p.parseTypeSelector()
+ if err != nil {
+ return nil, err
+ }
+ result = r
+ }
+
+loop:
+ for p.i < len(p.s) {
+ var ns Selector
+ var err error
+ switch p.s[p.i] {
+ case '#':
+ ns, err = p.parseIDSelector()
+ case '.':
+ ns, err = p.parseClassSelector()
+ case '[':
+ ns, err = p.parseAttributeSelector()
+ case ':':
+ ns, err = p.parsePseudoclassSelector()
+ default:
+ break loop
+ }
+ if err != nil {
+ return nil, err
+ }
+ if result == nil {
+ result = ns
+ } else {
+ result = intersectionSelector(result, ns)
+ }
+ }
+
+ if result == nil {
+ result = func(n *html.Node) bool {
+ return n.Type == html.ElementNode
+ }
+ }
+
+ return result, nil
+}
+
+// parseSelector parses a selector that may include combinators.
+func (p *parser) parseSelector() (result Selector, err error) {
+ p.skipWhitespace()
+ result, err = p.parseSimpleSelectorSequence()
+ if err != nil {
+ return
+ }
+
+ for {
+ var combinator byte
+ if p.skipWhitespace() {
+ combinator = ' '
+ }
+ if p.i >= len(p.s) {
+ return
+ }
+
+ switch p.s[p.i] {
+ case '+', '>', '~':
+ combinator = p.s[p.i]
+ p.i++
+ p.skipWhitespace()
+ case ',', ')':
+ // These characters can't begin a selector, but they can legally occur after one.
+ return
+ }
+
+ if combinator == 0 {
+ return
+ }
+
+ c, err := p.parseSimpleSelectorSequence()
+ if err != nil {
+ return nil, err
+ }
+
+ switch combinator {
+ case ' ':
+ result = descendantSelector(result, c)
+ case '>':
+ result = childSelector(result, c)
+ case '+':
+ result = siblingSelector(result, c, true)
+ case '~':
+ result = siblingSelector(result, c, false)
+ }
+ }
+
+ panic("unreachable")
+}
+
+// parseSelectorGroup parses a group of selectors, separated by commas.
+func (p *parser) parseSelectorGroup() (result Selector, err error) {
+ result, err = p.parseSelector()
+ if err != nil {
+ return
+ }
+
+ for p.i < len(p.s) {
+ if p.s[p.i] != ',' {
+ return result, nil
+ }
+ p.i++
+ c, err := p.parseSelector()
+ if err != nil {
+ return nil, err
+ }
+ result = unionSelector(result, c)
+ }
+
+ return
+}
diff --git a/vendor/github.com/andybalholm/cascadia/selector.go b/vendor/github.com/andybalholm/cascadia/selector.go
new file mode 100644
index 0000000..9fb05cc
--- /dev/null
+++ b/vendor/github.com/andybalholm/cascadia/selector.go
@@ -0,0 +1,622 @@
+package cascadia
+
+import (
+ "bytes"
+ "fmt"
+ "regexp"
+ "strings"
+
+ "golang.org/x/net/html"
+)
+
+// the Selector type, and functions for creating them
+
+// A Selector is a function which tells whether a node matches or not.
+type Selector func(*html.Node) bool
+
+// hasChildMatch returns whether n has any child that matches a.
+func hasChildMatch(n *html.Node, a Selector) bool {
+ for c := n.FirstChild; c != nil; c = c.NextSibling {
+ if a(c) {
+ return true
+ }
+ }
+ return false
+}
+
+// hasDescendantMatch performs a depth-first search of n's descendants,
+// testing whether any of them match a. It returns true as soon as a match is
+// found, or false if no match is found.
+func hasDescendantMatch(n *html.Node, a Selector) bool {
+ for c := n.FirstChild; c != nil; c = c.NextSibling {
+ if a(c) || (c.Type == html.ElementNode && hasDescendantMatch(c, a)) {
+ return true
+ }
+ }
+ return false
+}
+
+// Compile parses a selector and returns, if successful, a Selector object
+// that can be used to match against html.Node objects.
+func Compile(sel string) (Selector, error) {
+ p := &parser{s: sel}
+ compiled, err := p.parseSelectorGroup()
+ if err != nil {
+ return nil, err
+ }
+
+ if p.i < len(sel) {
+ return nil, fmt.Errorf("parsing %q: %d bytes left over", sel, len(sel)-p.i)
+ }
+
+ return compiled, nil
+}
+
+// MustCompile is like Compile, but panics instead of returning an error.
+func MustCompile(sel string) Selector {
+ compiled, err := Compile(sel)
+ if err != nil {
+ panic(err)
+ }
+ return compiled
+}
+
+// MatchAll returns a slice of the nodes that match the selector,
+// from n and its children.
+func (s Selector) MatchAll(n *html.Node) []*html.Node {
+ return s.matchAllInto(n, nil)
+}
+
+func (s Selector) matchAllInto(n *html.Node, storage []*html.Node) []*html.Node {
+ if s(n) {
+ storage = append(storage, n)
+ }
+
+ for child := n.FirstChild; child != nil; child = child.NextSibling {
+ storage = s.matchAllInto(child, storage)
+ }
+
+ return storage
+}
+
+// Match returns true if the node matches the selector.
+func (s Selector) Match(n *html.Node) bool {
+ return s(n)
+}
+
+// MatchFirst returns the first node that matches s, from n and its children.
+func (s Selector) MatchFirst(n *html.Node) *html.Node {
+ if s.Match(n) {
+ return n
+ }
+
+ for c := n.FirstChild; c != nil; c = c.NextSibling {
+ m := s.MatchFirst(c)
+ if m != nil {
+ return m
+ }
+ }
+ return nil
+}
+
+// Filter returns the nodes in nodes that match the selector.
+func (s Selector) Filter(nodes []*html.Node) (result []*html.Node) {
+ for _, n := range nodes {
+ if s(n) {
+ result = append(result, n)
+ }
+ }
+ return result
+}
+
+// typeSelector returns a Selector that matches elements with a given tag name.
+func typeSelector(tag string) Selector {
+ tag = toLowerASCII(tag)
+ return func(n *html.Node) bool {
+ return n.Type == html.ElementNode && n.Data == tag
+ }
+}
+
+// toLowerASCII returns s with all ASCII capital letters lowercased.
+func toLowerASCII(s string) string {
+ var b []byte
+ for i := 0; i < len(s); i++ {
+ if c := s[i]; 'A' <= c && c <= 'Z' {
+ if b == nil {
+ b = make([]byte, len(s))
+ copy(b, s)
+ }
+ b[i] = s[i] + ('a' - 'A')
+ }
+ }
+
+ if b == nil {
+ return s
+ }
+
+ return string(b)
+}
+
+// attributeSelector returns a Selector that matches elements
+// where the attribute named key satisifes the function f.
+func attributeSelector(key string, f func(string) bool) Selector {
+ key = toLowerASCII(key)
+ return func(n *html.Node) bool {
+ if n.Type != html.ElementNode {
+ return false
+ }
+ for _, a := range n.Attr {
+ if a.Key == key && f(a.Val) {
+ return true
+ }
+ }
+ return false
+ }
+}
+
+// attributeExistsSelector returns a Selector that matches elements that have
+// an attribute named key.
+func attributeExistsSelector(key string) Selector {
+ return attributeSelector(key, func(string) bool { return true })
+}
+
+// attributeEqualsSelector returns a Selector that matches elements where
+// the attribute named key has the value val.
+func attributeEqualsSelector(key, val string) Selector {
+ return attributeSelector(key,
+ func(s string) bool {
+ return s == val
+ })
+}
+
+// attributeNotEqualSelector returns a Selector that matches elements where
+// the attribute named key does not have the value val.
+func attributeNotEqualSelector(key, val string) Selector {
+ key = toLowerASCII(key)
+ return func(n *html.Node) bool {
+ if n.Type != html.ElementNode {
+ return false
+ }
+ for _, a := range n.Attr {
+ if a.Key == key && a.Val == val {
+ return false
+ }
+ }
+ return true
+ }
+}
+
+// attributeIncludesSelector returns a Selector that matches elements where
+// the attribute named key is a whitespace-separated list that includes val.
+func attributeIncludesSelector(key, val string) Selector {
+ return attributeSelector(key,
+ func(s string) bool {
+ for s != "" {
+ i := strings.IndexAny(s, " \t\r\n\f")
+ if i == -1 {
+ return s == val
+ }
+ if s[:i] == val {
+ return true
+ }
+ s = s[i+1:]
+ }
+ return false
+ })
+}
+
+// attributeDashmatchSelector returns a Selector that matches elements where
+// the attribute named key equals val or starts with val plus a hyphen.
+func attributeDashmatchSelector(key, val string) Selector {
+ return attributeSelector(key,
+ func(s string) bool {
+ if s == val {
+ return true
+ }
+ if len(s) <= len(val) {
+ return false
+ }
+ if s[:len(val)] == val && s[len(val)] == '-' {
+ return true
+ }
+ return false
+ })
+}
+
+// attributePrefixSelector returns a Selector that matches elements where
+// the attribute named key starts with val.
+func attributePrefixSelector(key, val string) Selector {
+ return attributeSelector(key,
+ func(s string) bool {
+ if strings.TrimSpace(s) == "" {
+ return false
+ }
+ return strings.HasPrefix(s, val)
+ })
+}
+
+// attributeSuffixSelector returns a Selector that matches elements where
+// the attribute named key ends with val.
+func attributeSuffixSelector(key, val string) Selector {
+ return attributeSelector(key,
+ func(s string) bool {
+ if strings.TrimSpace(s) == "" {
+ return false
+ }
+ return strings.HasSuffix(s, val)
+ })
+}
+
+// attributeSubstringSelector returns a Selector that matches nodes where
+// the attribute named key contains val.
+func attributeSubstringSelector(key, val string) Selector {
+ return attributeSelector(key,
+ func(s string) bool {
+ if strings.TrimSpace(s) == "" {
+ return false
+ }
+ return strings.Contains(s, val)
+ })
+}
+
+// attributeRegexSelector returns a Selector that matches nodes where
+// the attribute named key matches the regular expression rx
+func attributeRegexSelector(key string, rx *regexp.Regexp) Selector {
+ return attributeSelector(key,
+ func(s string) bool {
+ return rx.MatchString(s)
+ })
+}
+
+// intersectionSelector returns a selector that matches nodes that match
+// both a and b.
+func intersectionSelector(a, b Selector) Selector {
+ return func(n *html.Node) bool {
+ return a(n) && b(n)
+ }
+}
+
+// unionSelector returns a selector that matches elements that match
+// either a or b.
+func unionSelector(a, b Selector) Selector {
+ return func(n *html.Node) bool {
+ return a(n) || b(n)
+ }
+}
+
+// negatedSelector returns a selector that matches elements that do not match a.
+func negatedSelector(a Selector) Selector {
+ return func(n *html.Node) bool {
+ if n.Type != html.ElementNode {
+ return false
+ }
+ return !a(n)
+ }
+}
+
+// writeNodeText writes the text contained in n and its descendants to b.
+func writeNodeText(n *html.Node, b *bytes.Buffer) {
+ switch n.Type {
+ case html.TextNode:
+ b.WriteString(n.Data)
+ case html.ElementNode:
+ for c := n.FirstChild; c != nil; c = c.NextSibling {
+ writeNodeText(c, b)
+ }
+ }
+}
+
+// nodeText returns the text contained in n and its descendants.
+func nodeText(n *html.Node) string {
+ var b bytes.Buffer
+ writeNodeText(n, &b)
+ return b.String()
+}
+
+// nodeOwnText returns the contents of the text nodes that are direct
+// children of n.
+func nodeOwnText(n *html.Node) string {
+ var b bytes.Buffer
+ for c := n.FirstChild; c != nil; c = c.NextSibling {
+ if c.Type == html.TextNode {
+ b.WriteString(c.Data)
+ }
+ }
+ return b.String()
+}
+
+// textSubstrSelector returns a selector that matches nodes that
+// contain the given text.
+func textSubstrSelector(val string) Selector {
+ return func(n *html.Node) bool {
+ text := strings.ToLower(nodeText(n))
+ return strings.Contains(text, val)
+ }
+}
+
+// ownTextSubstrSelector returns a selector that matches nodes that
+// directly contain the given text
+func ownTextSubstrSelector(val string) Selector {
+ return func(n *html.Node) bool {
+ text := strings.ToLower(nodeOwnText(n))
+ return strings.Contains(text, val)
+ }
+}
+
+// textRegexSelector returns a selector that matches nodes whose text matches
+// the specified regular expression
+func textRegexSelector(rx *regexp.Regexp) Selector {
+ return func(n *html.Node) bool {
+ return rx.MatchString(nodeText(n))
+ }
+}
+
+// ownTextRegexSelector returns a selector that matches nodes whose text
+// directly matches the specified regular expression
+func ownTextRegexSelector(rx *regexp.Regexp) Selector {
+ return func(n *html.Node) bool {
+ return rx.MatchString(nodeOwnText(n))
+ }
+}
+
+// hasChildSelector returns a selector that matches elements
+// with a child that matches a.
+func hasChildSelector(a Selector) Selector {
+ return func(n *html.Node) bool {
+ if n.Type != html.ElementNode {
+ return false
+ }
+ return hasChildMatch(n, a)
+ }
+}
+
+// hasDescendantSelector returns a selector that matches elements
+// with any descendant that matches a.
+func hasDescendantSelector(a Selector) Selector {
+ return func(n *html.Node) bool {
+ if n.Type != html.ElementNode {
+ return false
+ }
+ return hasDescendantMatch(n, a)
+ }
+}
+
+// nthChildSelector returns a selector that implements :nth-child(an+b).
+// If last is true, implements :nth-last-child instead.
+// If ofType is true, implements :nth-of-type instead.
+func nthChildSelector(a, b int, last, ofType bool) Selector {
+ return func(n *html.Node) bool {
+ if n.Type != html.ElementNode {
+ return false
+ }
+
+ parent := n.Parent
+ if parent == nil {
+ return false
+ }
+
+ if parent.Type == html.DocumentNode {
+ return false
+ }
+
+ i := -1
+ count := 0
+ for c := parent.FirstChild; c != nil; c = c.NextSibling {
+ if (c.Type != html.ElementNode) || (ofType && c.Data != n.Data) {
+ continue
+ }
+ count++
+ if c == n {
+ i = count
+ if !last {
+ break
+ }
+ }
+ }
+
+ if i == -1 {
+ // This shouldn't happen, since n should always be one of its parent's children.
+ return false
+ }
+
+ if last {
+ i = count - i + 1
+ }
+
+ i -= b
+ if a == 0 {
+ return i == 0
+ }
+
+ return i%a == 0 && i/a >= 0
+ }
+}
+
+// simpleNthChildSelector returns a selector that implements :nth-child(b).
+// If ofType is true, implements :nth-of-type instead.
+func simpleNthChildSelector(b int, ofType bool) Selector {
+ return func(n *html.Node) bool {
+ if n.Type != html.ElementNode {
+ return false
+ }
+
+ parent := n.Parent
+ if parent == nil {
+ return false
+ }
+
+ if parent.Type == html.DocumentNode {
+ return false
+ }
+
+ count := 0
+ for c := parent.FirstChild; c != nil; c = c.NextSibling {
+ if c.Type != html.ElementNode || (ofType && c.Data != n.Data) {
+ continue
+ }
+ count++
+ if c == n {
+ return count == b
+ }
+ if count >= b {
+ return false
+ }
+ }
+ return false
+ }
+}
+
+// simpleNthLastChildSelector returns a selector that implements
+// :nth-last-child(b). If ofType is true, implements :nth-last-of-type
+// instead.
+func simpleNthLastChildSelector(b int, ofType bool) Selector {
+ return func(n *html.Node) bool {
+ if n.Type != html.ElementNode {
+ return false
+ }
+
+ parent := n.Parent
+ if parent == nil {
+ return false
+ }
+
+ if parent.Type == html.DocumentNode {
+ return false
+ }
+
+ count := 0
+ for c := parent.LastChild; c != nil; c = c.PrevSibling {
+ if c.Type != html.ElementNode || (ofType && c.Data != n.Data) {
+ continue
+ }
+ count++
+ if c == n {
+ return count == b
+ }
+ if count >= b {
+ return false
+ }
+ }
+ return false
+ }
+}
+
+// onlyChildSelector returns a selector that implements :only-child.
+// If ofType is true, it implements :only-of-type instead.
+func onlyChildSelector(ofType bool) Selector {
+ return func(n *html.Node) bool {
+ if n.Type != html.ElementNode {
+ return false
+ }
+
+ parent := n.Parent
+ if parent == nil {
+ return false
+ }
+
+ if parent.Type == html.DocumentNode {
+ return false
+ }
+
+ count := 0
+ for c := parent.FirstChild; c != nil; c = c.NextSibling {
+ if (c.Type != html.ElementNode) || (ofType && c.Data != n.Data) {
+ continue
+ }
+ count++
+ if count > 1 {
+ return false
+ }
+ }
+
+ return count == 1
+ }
+}
+
+// inputSelector is a Selector that matches input, select, textarea and button elements.
+func inputSelector(n *html.Node) bool {
+ return n.Type == html.ElementNode && (n.Data == "input" || n.Data == "select" || n.Data == "textarea" || n.Data == "button")
+}
+
+// emptyElementSelector is a Selector that matches empty elements.
+func emptyElementSelector(n *html.Node) bool {
+ if n.Type != html.ElementNode {
+ return false
+ }
+
+ for c := n.FirstChild; c != nil; c = c.NextSibling {
+ switch c.Type {
+ case html.ElementNode, html.TextNode:
+ return false
+ }
+ }
+
+ return true
+}
+
+// descendantSelector returns a Selector that matches an element if
+// it matches d and has an ancestor that matches a.
+func descendantSelector(a, d Selector) Selector {
+ return func(n *html.Node) bool {
+ if !d(n) {
+ return false
+ }
+
+ for p := n.Parent; p != nil; p = p.Parent {
+ if a(p) {
+ return true
+ }
+ }
+
+ return false
+ }
+}
+
+// childSelector returns a Selector that matches an element if
+// it matches d and its parent matches a.
+func childSelector(a, d Selector) Selector {
+ return func(n *html.Node) bool {
+ return d(n) && n.Parent != nil && a(n.Parent)
+ }
+}
+
+// siblingSelector returns a Selector that matches an element
+// if it matches s2 and in is preceded by an element that matches s1.
+// If adjacent is true, the sibling must be immediately before the element.
+func siblingSelector(s1, s2 Selector, adjacent bool) Selector {
+ return func(n *html.Node) bool {
+ if !s2(n) {
+ return false
+ }
+
+ if adjacent {
+ for n = n.PrevSibling; n != nil; n = n.PrevSibling {
+ if n.Type == html.TextNode || n.Type == html.CommentNode {
+ continue
+ }
+ return s1(n)
+ }
+ return false
+ }
+
+ // Walk backwards looking for element that matches s1
+ for c := n.PrevSibling; c != nil; c = c.PrevSibling {
+ if s1(c) {
+ return true
+ }
+ }
+
+ return false
+ }
+}
+
+// rootSelector implements :root
+func rootSelector(n *html.Node) bool {
+ if n.Type != html.ElementNode {
+ return false
+ }
+ if n.Parent == nil {
+ return false
+ }
+ return n.Parent.Type == html.DocumentNode
+}
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