Implement html.unescape and html.entities.html5

Author: singingwolfboy

src/future/moves/html/__init__.py

@@ -1,4 +1,4 @@
-from __future__ import absolute_import
+from __future__ import absolute_import, unicode_literals
 from future.utils import PY3
 __future_module__ = True
 
@@ -13,6 +13,18 @@
     General functions for HTML manipulation.
     """
 
+    import re as _re
+    from future.moves.html.entities import html5 as _html5
+
+    _chr = chr
+    def chr(num):
+        if num in range(256):
+            return _chr(num)
+        try:
+            return unichr(num)
+        except ValueError:
+            return str('\\U%08x' % num).decode('unicode-escape')
+
     def escape(s, quote=True):
         """
         Replace special characters "&", "<" and ">" to HTML-safe sequences.
@@ -28,4 +40,111 @@ def escape(s, quote=True):
             s = s.replace('\'', "&#x27;")
         return s
 
-    __all__ = ['escape']
+
+    # see http://www.w3.org/TR/html5/syntax.html#tokenizing-character-references
+
+    _invalid_charrefs = {
+        0x00: '\ufffd',  # REPLACEMENT CHARACTER
+        0x0d: '\r',      # CARRIAGE RETURN
+        0x80: '\u20ac',  # EURO SIGN
+        0x81: '\x81',    # <control>
+        0x82: '\u201a',  # SINGLE LOW-9 QUOTATION MARK
+        0x83: '\u0192',  # LATIN SMALL LETTER F WITH HOOK
+        0x84: '\u201e',  # DOUBLE LOW-9 QUOTATION MARK
+        0x85: '\u2026',  # HORIZONTAL ELLIPSIS
+        0x86: '\u2020',  # DAGGER
+        0x87: '\u2021',  # DOUBLE DAGGER
+        0x88: '\u02c6',  # MODIFIER LETTER CIRCUMFLEX ACCENT
+        0x89: '\u2030',  # PER MILLE SIGN
+        0x8a: '\u0160',  # LATIN CAPITAL LETTER S WITH CARON
+        0x8b: '\u2039',  # SINGLE LEFT-POINTING ANGLE QUOTATION MARK
+        0x8c: '\u0152',  # LATIN CAPITAL LIGATURE OE
+        0x8d: '\x8d',    # <control>
+        0x8e: '\u017d',  # LATIN CAPITAL LETTER Z WITH CARON
+        0x8f: '\x8f',    # <control>
+        0x90: '\x90',    # <control>
+        0x91: '\u2018',  # LEFT SINGLE QUOTATION MARK
+        0x92: '\u2019',  # RIGHT SINGLE QUOTATION MARK
+        0x93: '\u201c',  # LEFT DOUBLE QUOTATION MARK
+        0x94: '\u201d',  # RIGHT DOUBLE QUOTATION MARK
+        0x95: '\u2022',  # BULLET
+        0x96: '\u2013',  # EN DASH
+        0x97: '\u2014',  # EM DASH
+        0x98: '\u02dc',  # SMALL TILDE
+        0x99: '\u2122',  # TRADE MARK SIGN
+        0x9a: '\u0161',  # LATIN SMALL LETTER S WITH CARON
+        0x9b: '\u203a',  # SINGLE RIGHT-POINTING ANGLE QUOTATION MARK
+        0x9c: '\u0153',  # LATIN SMALL LIGATURE OE
+        0x9d: '\x9d',    # <control>
+        0x9e: '\u017e',  # LATIN SMALL LETTER Z WITH CARON
+        0x9f: '\u0178',  # LATIN CAPITAL LETTER Y WITH DIAERESIS
+    }
+
+    _invalid_codepoints = {
+        # 0x0001 to 0x0008
+        0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8,
+        # 0x000E to 0x001F
+        0xe, 0xf, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19,
+        0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+        # 0x007F to 0x009F
+        0x7f, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a,
+        0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96,
+        0x97, 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
+        # 0xFDD0 to 0xFDEF
+        0xfdd0, 0xfdd1, 0xfdd2, 0xfdd3, 0xfdd4, 0xfdd5, 0xfdd6, 0xfdd7, 0xfdd8,
+        0xfdd9, 0xfdda, 0xfddb, 0xfddc, 0xfddd, 0xfdde, 0xfddf, 0xfde0, 0xfde1,
+        0xfde2, 0xfde3, 0xfde4, 0xfde5, 0xfde6, 0xfde7, 0xfde8, 0xfde9, 0xfdea,
+        0xfdeb, 0xfdec, 0xfded, 0xfdee, 0xfdef,
+        # others
+        0xb, 0xfffe, 0xffff, 0x1fffe, 0x1ffff, 0x2fffe, 0x2ffff, 0x3fffe, 0x3ffff,
+        0x4fffe, 0x4ffff, 0x5fffe, 0x5ffff, 0x6fffe, 0x6ffff, 0x7fffe, 0x7ffff,
+        0x8fffe, 0x8ffff, 0x9fffe, 0x9ffff, 0xafffe, 0xaffff, 0xbfffe, 0xbffff,
+        0xcfffe, 0xcffff, 0xdfffe, 0xdffff, 0xefffe, 0xeffff, 0xffffe, 0xfffff,
+        0x10fffe, 0x10ffff
+    }
+
+
+    def _replace_charref(s):
+        s = s.group(1)
+        if s[0] == '#':
+            # numeric charref
+            if s[1] in 'xX':
+                num = int(s[2:].rstrip(';'), 16)
+            else:
+                num = int(s[1:].rstrip(';'))
+            if num in _invalid_charrefs:
+                return _invalid_charrefs[num]
+            if 0xD800 <= num <= 0xDFFF or num > 0x10FFFF:
+                return '\uFFFD'
+            if num in _invalid_codepoints:
+                return ''
+            return chr(num)
+        else:
+            # named charref
+            if s in _html5:
+                return _html5[s]
+            # find the longest matching name (as defined by the standard)
+            for x in range(len(s)-1, 1, -1):
+                if s[:x] in _html5:
+                    return _html5[s[:x]] + s[x:]
+            else:
+                return '&' + s
+
+
+    _charref = _re.compile(r'&(#[0-9]+;?'
+                        r'|#[xX][0-9a-fA-F]+;?'
+                        r'|[^\t\n\f <&#;]{1,32};?)')
+
+    def unescape(s):
+        """
+        Convert all named and numeric character references (e.g. &gt;, &#62;,
+        &x3e;) in the string s to the corresponding unicode characters.
+        This function uses the rules defined by the HTML 5 standard
+        for both valid and invalid character references, and the list of
+        HTML 5 named character references defined in html.entities.html5.
+        """
+        if '&' not in s:
+            return s
+        return _charref.sub(_replace_charref, s)
+
+    __all__ = [b'escape', b'unescape']