1 files changed, 339 insertions, 0 deletions

diff --git a/vendor/golang.org/x/net/html/escape.go b/vendor/golang.org/x/net/html/escape.go
new file mode 100644
index 0000000..04c6bec
--- /dev/null
+++ b/vendor/golang.org/x/net/html/escape.go
@@ -0,0 +1,339 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package html
+
+import (
+        "bytes"
+        "strings"
+        "unicode/utf8"
+)
+
+// These replacements permit compatibility with old numeric entities that
+// assumed Windows-1252 encoding.
+// https://html.spec.whatwg.org/multipage/syntax.html#consume-a-character-reference
+var replacementTable = [...]rune{
+        '\u20AC', // First entry is what 0x80 should be replaced with.
+        '\u0081',
+        '\u201A',
+        '\u0192',
+        '\u201E',
+        '\u2026',
+        '\u2020',
+        '\u2021',
+        '\u02C6',
+        '\u2030',
+        '\u0160',
+        '\u2039',
+        '\u0152',
+        '\u008D',
+        '\u017D',
+        '\u008F',
+        '\u0090',
+        '\u2018',
+        '\u2019',
+        '\u201C',
+        '\u201D',
+        '\u2022',
+        '\u2013',
+        '\u2014',
+        '\u02DC',
+        '\u2122',
+        '\u0161',
+        '\u203A',
+        '\u0153',
+        '\u009D',
+        '\u017E',
+        '\u0178', // Last entry is 0x9F.
+        // 0x00->'\uFFFD' is handled programmatically.
+        // 0x0D->'\u000D' is a no-op.
+}
+
+// unescapeEntity reads an entity like "<" from b[src:] and writes the
+// corresponding "<" to b[dst:], returning the incremented dst and src cursors.
+// Precondition: b[src] == '&' && dst <= src.
+// attribute should be true if parsing an attribute value.
+func unescapeEntity(b []byte, dst, src int, attribute bool) (dst1, src1 int) {
+        // https://html.spec.whatwg.org/multipage/syntax.html#consume-a-character-reference
+
+        // i starts at 1 because we already know that s[0] == '&'.
+        i, s := 1, b[src:]
+
+        if len(s) <= 1 {
+                b[dst] = b[src]
+                return dst + 1, src + 1
+        }
+
+        if s[i] == '#' {
+                if len(s) <= 3 { // We need to have at least "&#.".
+                        b[dst] = b[src]
+                        return dst + 1, src + 1
+                }
+                i++
+                c := s[i]
+                hex := false
+                if c == 'x' || c == 'X' {
+                        hex = true
+                        i++
+                }
+
+                x := '\x00'
+                for i < len(s) {
+                        c = s[i]
+                        i++
+                        if hex {
+                                if '0' <= c && c <= '9' {
+                                        x = 16*x + rune(c) - '0'
+                                        continue
+                                } else if 'a' <= c && c <= 'f' {
+                                        x = 16*x + rune(c) - 'a' + 10
+                                        continue
+                                } else if 'A' <= c && c <= 'F' {
+                                        x = 16*x + rune(c) - 'A' + 10
+                                        continue
+                                }
+                        } else if '0' <= c && c <= '9' {
+                                x = 10*x + rune(c) - '0'
+                                continue
+                        }
+                        if c != ';' {
+                                i--
+                        }
+                        break
+                }
+
+                if i <= 3 { // No characters matched.
+                        b[dst] = b[src]
+                        return dst + 1, src + 1
+                }
+
+                if 0x80 <= x && x <= 0x9F {
+                        // Replace characters from Windows-1252 with UTF-8 equivalents.
+                        x = replacementTable[x-0x80]
+                } else if x == 0 || (0xD800 <= x && x <= 0xDFFF) || x > 0x10FFFF {
+                        // Replace invalid characters with the replacement character.
+                        x = '\uFFFD'
+                }
+
+                return dst + utf8.EncodeRune(b[dst:], x), src + i
+        }
+
+        // Consume the maximum number of characters possible, with the
+        // consumed characters matching one of the named references.
+
+        for i < len(s) {
+                c := s[i]
+                i++
+                // Lower-cased characters are more common in entities, so we check for them first.
+                if 'a' <= c && c <= 'z' || 'A' <= c && c <= 'Z' || '0' <= c && c <= '9' {
+                        continue
+                }
+                if c != ';' {
+                        i--
+                }
+                break
+        }
+
+        entityName := string(s[1:i])
+        if entityName == "" {
+                // No-op.
+        } else if attribute && entityName[len(entityName)-1] != ';' && len(s) > i && s[i] == '=' {
+                // No-op.
+        } else if x := entity[entityName]; x != 0 {
+                return dst + utf8.EncodeRune(b[dst:], x), src + i
+        } else if x := entity2[entityName]; x[0] != 0 {
+                dst1 := dst + utf8.EncodeRune(b[dst:], x[0])
+                return dst1 + utf8.EncodeRune(b[dst1:], x[1]), src + i
+        } else if !attribute {
+                maxLen := len(entityName) - 1
+                if maxLen > longestEntityWithoutSemicolon {
+                        maxLen = longestEntityWithoutSemicolon
+                }
+                for j := maxLen; j > 1; j-- {
+                        if x := entity[entityName[:j]]; x != 0 {
+                                return dst + utf8.EncodeRune(b[dst:], x), src + j + 1
+                        }
+                }
+        }
+
+        dst1, src1 = dst+i, src+i
+        copy(b[dst:dst1], b[src:src1])
+        return dst1, src1
+}
+
+// unescape unescapes b's entities in-place, so that "a&lt;b" becomes "a<b".
+// attribute should be true if parsing an attribute value.
+func unescape(b []byte, attribute bool) []byte {
+        for i, c := range b {
+                if c == '&' {
+                        dst, src := unescapeEntity(b, i, i, attribute)
+                        for src < len(b) {
+                                c := b[src]
+                                if c == '&' {
+                                        dst, src = unescapeEntity(b, dst, src, attribute)
+                                } else {
+                                        b[dst] = c
+                                        dst, src = dst+1, src+1
+                                }
+                        }
+                        return b[0:dst]
+                }
+        }
+        return b
+}
+
+// lower lower-cases the A-Z bytes in b in-place, so that "aBc" becomes "abc".
+func lower(b []byte) []byte {
+        for i, c := range b {
+                if 'A' <= c && c <= 'Z' {
+                        b[i] = c + 'a' - 'A'
+                }
+        }
+        return b
+}
+
+// escapeComment is like func escape but escapes its input bytes less often.
+// Per https://github.com/golang/go/issues/58246 some HTML comments are (1)
+// meaningful and (2) contain angle brackets that we'd like to avoid escaping
+// unless we have to.
+//
+// "We have to" includes the '&' byte, since that introduces other escapes.
+//
+// It also includes those bytes (not including EOF) that would otherwise end
+// the comment. Per the summary table at the bottom of comment_test.go, this is
+// the '>' byte that, per above, we'd like to avoid escaping unless we have to.
+//
+// Studying the summary table (and T actions in its '>' column) closely, we
+// only need to escape in states 43, 44, 49, 51 and 52. State 43 is at the
+// start of the comment data. State 52 is after a '!'. The other three states
+// are after a '-'.
+//
+// Our algorithm is thus to escape every '&' and to escape '>' if and only if:
+//   - The '>' is after a '!' or '-' (in the unescaped data) or
+//   - The '>' is at the start of the comment data (after the opening "<!--").
+func escapeComment(w writer, s string) error {
+        // When modifying this function, consider manually increasing the
+        // maxSuffixLen constant in func TestComments, from 6 to e.g. 9 or more.
+        // That increase should only be temporary, not committed, as it
+        // exponentially affects the test running time.
+
+        if len(s) == 0 {
+                return nil
+        }
+
+        // Loop:
+        //   - Grow j such that s[i:j] does not need escaping.
+        //   - If s[j] does need escaping, output s[i:j] and an escaped s[j],
+        //     resetting i and j to point past that s[j] byte.
+        i := 0
+        for j := 0; j < len(s); j++ {
+                escaped := ""
+                switch s[j] {
+                case '&':
+                        escaped = "&amp;"
+
+                case '>':
+                        if j > 0 {
+                                if prev := s[j-1]; (prev != '!') && (prev != '-') {
+                                        continue
+                                }
+                        }
+                        escaped = "&gt;"
+
+                default:
+                        continue
+                }
+
+                if i < j {
+                        if _, err := w.WriteString(s[i:j]); err != nil {
+                                return err
+                        }
+                }
+                if _, err := w.WriteString(escaped); err != nil {
+                        return err
+                }
+                i = j + 1
+        }
+
+        if i < len(s) {
+                if _, err := w.WriteString(s[i:]); err != nil {
+                        return err
+                }
+        }
+        return nil
+}
+
+// escapeCommentString is to EscapeString as escapeComment is to escape.
+func escapeCommentString(s string) string {
+        if strings.IndexAny(s, "&>") == -1 {
+                return s
+        }
+        var buf bytes.Buffer
+        escapeComment(&buf, s)
+        return buf.String()
+}
+
+const escapedChars = "&'<>\"\r"
+
+func escape(w writer, s string) error {
+        i := strings.IndexAny(s, escapedChars)
+        for i != -1 {
+                if _, err := w.WriteString(s[:i]); err != nil {
+                        return err
+                }
+                var esc string
+                switch s[i] {
+                case '&':
+                        esc = "&amp;"
+                case '\'':
+                        // "&#39;" is shorter than "&apos;" and apos was not in HTML until HTML5.
+                        esc = "&#39;"
+                case '<':
+                        esc = "&lt;"
+                case '>':
+                        esc = "&gt;"
+                case '"':
+                        // "&#34;" is shorter than "&quot;".
+                        esc = "&#34;"
+                case '\r':
+                        esc = "&#13;"
+                default:
+                        panic("unrecognized escape character")
+                }
+                s = s[i+1:]
+                if _, err := w.WriteString(esc); err != nil {
+                        return err
+                }
+                i = strings.IndexAny(s, escapedChars)
+        }
+        _, err := w.WriteString(s)
+        return err
+}
+
+// EscapeString escapes special characters like "<" to become "&lt;". It
+// escapes only five such characters: <, >, &, ' and ".
+// UnescapeString(EscapeString(s)) == s always holds, but the converse isn't
+// always true.
+func EscapeString(s string) string {
+        if strings.IndexAny(s, escapedChars) == -1 {
+                return s
+        }
+        var buf bytes.Buffer
+        escape(&buf, s)
+        return buf.String()
+}
+
+// UnescapeString unescapes entities like "&lt;" to become "<". It unescapes a
+// larger range of entities than EscapeString escapes. For example, "&aacute;"
+// unescapes to "á", as does "&#225;" and "&xE1;".
+// UnescapeString(EscapeString(s)) == s always holds, but the converse isn't
+// always true.
+func UnescapeString(s string) string {
+        for _, c := range s {
+                if c == '&' {
+                        return string(unescape([]byte(s), false))
+                }
+        }
+        return s
+}