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import re
import sys
from webencodings import ascii_lower
from .ast import ( # isort: skip
AtKeywordToken, Comment, CurlyBracketsBlock, DimensionToken, FunctionBlock,
HashToken, IdentToken, LiteralToken, NumberToken, ParenthesesBlock, ParseError,
PercentageToken, SquareBracketsBlock, StringToken, UnicodeRangeToken, URLToken,
WhitespaceToken)
from .serializer import serialize_string_value, serialize_url
_NUMBER_RE = re.compile(r'[-+]?([0-9]*\.)?[0-9]+([eE][+-]?[0-9]+)?')
_HEX_ESCAPE_RE = re.compile(r'([0-9A-Fa-f]{1,6})[ \n\t]?')
def parse_component_value_list(css, skip_comments=False):
"""Parse a list of component values.
:type css: :obj:`str`
:param css: A CSS string.
:type skip_comments: :obj:`bool`
:param skip_comments:
Ignore CSS comments.
The return values (and recursively its blocks and functions)
will not contain any :class:`~tinycss2.ast.Comment` object.
:returns: A list of :term:`component values`.
"""
css = (css.replace('\0', '\uFFFD')
# This turns out to be faster than a regexp:
.replace('\r\n', '\n').replace('\r', '\n').replace('\f', '\n'))
length = len(css)
token_start_pos = pos = 0 # Character index in the css source.
line = 1 # First line is line 1.
last_newline = -1
root = tokens = []
end_char = None # Pop the stack when encountering this character.
stack = [] # Stack of nested blocks: (tokens, end_char) tuples.
while pos < length:
newline = css.rfind('\n', token_start_pos, pos)
if newline != -1:
line += 1 + css.count('\n', token_start_pos, newline)
last_newline = newline
# First character in a line is in column 1.
column = pos - last_newline
token_start_pos = pos
c = css[pos]
if c in ' \n\t':
pos += 1
while css.startswith((' ', '\n', '\t'), pos):
pos += 1
value = css[token_start_pos:pos]
tokens.append(WhitespaceToken(line, column, value))
continue
elif (c in 'Uu' and pos + 2 < length and css[pos + 1] == '+' and
css[pos + 2] in '0123456789abcdefABCDEF?'):
start, end, pos = _consume_unicode_range(css, pos + 2)
tokens.append(UnicodeRangeToken(line, column, start, end))
continue
elif css.startswith('-->', pos): # Check before identifiers
tokens.append(LiteralToken(line, column, '-->'))
pos += 3
continue
elif _is_ident_start(css, pos):
value, pos = _consume_ident(css, pos)
if not css.startswith('(', pos): # Not a function
tokens.append(IdentToken(line, column, value))
continue
pos += 1 # Skip the '('
if ascii_lower(value) == 'url':
url_pos = pos
while css.startswith((' ', '\n', '\t'), url_pos):
url_pos += 1
if url_pos >= length or css[url_pos] not in ('"', "'"):
value, pos, error = _consume_url(css, pos)
if value is not None:
repr = 'url({})'.format(serialize_url(value))
if error is not None:
error_key = error[0]
if error_key == 'eof-in-string':
repr = repr[:-2]
else:
assert error_key == 'eof-in-url'
repr = repr[:-1]
tokens.append(URLToken(line, column, value, repr))
if error is not None:
tokens.append(ParseError(line, column, *error))
continue
arguments = []
tokens.append(FunctionBlock(line, column, value, arguments))
stack.append((tokens, end_char))
end_char = ')'
tokens = arguments
continue
match = _NUMBER_RE.match(css, pos)
if match:
pos = match.end()
repr_ = css[token_start_pos:pos]
value = float(repr_)
int_value = int(repr_) if not any(match.groups()) else None
if pos < length and _is_ident_start(css, pos):
unit, pos = _consume_ident(css, pos)
tokens.append(DimensionToken(
line, column, value, int_value, repr_, unit))
elif css.startswith('%', pos):
pos += 1
tokens.append(PercentageToken(line, column, value, int_value, repr_))
else:
tokens.append(NumberToken(line, column, value, int_value, repr_))
elif c == '@':
pos += 1
if pos < length and _is_ident_start(css, pos):
value, pos = _consume_ident(css, pos)
tokens.append(AtKeywordToken(line, column, value))
else:
tokens.append(LiteralToken(line, column, '@'))
elif c == '#':
pos += 1
if pos < length and (
css[pos] in '0123456789abcdefghijklmnopqrstuvwxyz'
'-_ABCDEFGHIJKLMNOPQRSTUVWXYZ' or
ord(css[pos]) > 0x7F or # Non-ASCII
# Valid escape:
(css[pos] == '\\' and not css.startswith('\\\n', pos))):
is_identifier = _is_ident_start(css, pos)
value, pos = _consume_ident(css, pos)
tokens.append(HashToken(line, column, value, is_identifier))
else:
tokens.append(LiteralToken(line, column, '#'))
elif c == '{':
content = []
tokens.append(CurlyBracketsBlock(line, column, content))
stack.append((tokens, end_char))
end_char = '}'
tokens = content
pos += 1
elif c == '[':
content = []
tokens.append(SquareBracketsBlock(line, column, content))
stack.append((tokens, end_char))
end_char = ']'
tokens = content
pos += 1
elif c == '(':
content = []
tokens.append(ParenthesesBlock(line, column, content))
stack.append((tokens, end_char))
end_char = ')'
tokens = content
pos += 1
elif c == end_char: # Matching }, ] or )
# The top-level end_char is None (never equal to a character),
# so we never get here if the stack is empty.
tokens, end_char = stack.pop()
pos += 1
elif c in '}])':
tokens.append(ParseError(line, column, c, 'Unmatched ' + c))
pos += 1
elif c in ('"', "'"):
value, pos, error = _consume_quoted_string(css, pos)
if value is not None:
repr = '"{}"'.format(serialize_string_value(value))
if error is not None:
repr = repr[:-1]
tokens.append(StringToken(line, column, value, repr))
if error is not None:
tokens.append(ParseError(line, column, *error))
elif css.startswith('/*', pos): # Comment
pos = css.find('*/', pos + 2)
if pos == -1:
if not skip_comments:
tokens.append(Comment(line, column, css[token_start_pos + 2:]))
break
if not skip_comments:
tokens.append(Comment(line, column, css[token_start_pos + 2:pos]))
pos += 2
elif css.startswith('<!--', pos):
tokens.append(LiteralToken(line, column, '<!--'))
pos += 4
elif css.startswith('||', pos):
tokens.append(LiteralToken(line, column, '||'))
pos += 2
elif c in '~|^$*':
pos += 1
if css.startswith('=', pos):
pos += 1
tokens.append(LiteralToken(line, column, c + '='))
else:
tokens.append(LiteralToken(line, column, c))
else:
tokens.append(LiteralToken(line, column, c))
pos += 1
return root
def _is_name_start(css, pos):
"""Return true if the given character is a name-start code point."""
# https://www.w3.org/TR/css-syntax-3/#name-start-code-point
c = css[pos]
return (
c in 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_' or
ord(c) > 0x7F)
def _is_ident_start(css, pos):
"""Return True if the given position is the start of a CSS identifier."""
# https://drafts.csswg.org/css-syntax/#would-start-an-identifier
if _is_name_start(css, pos):
return True
elif css[pos] == '-':
pos += 1
return (
# Name-start code point or hyphen:
(pos < len(css) and (_is_name_start(css, pos) or css[pos] == '-')) or
# Valid escape:
(css.startswith('\\', pos) and not css.startswith('\\\n', pos)))
elif css[pos] == '\\':
return not css.startswith('\\\n', pos)
return False
def _consume_ident(css, pos):
"""Return (unescaped_value, new_pos).
Assumes pos starts at a valid identifier. See :func:`_is_ident_start`.
"""
# http://dev.w3.org/csswg/css-syntax/#consume-a-name
chunks = []
length = len(css)
start_pos = pos
while pos < length:
c = css[pos]
if c in ('abcdefghijklmnopqrstuvwxyz-_0123456789'
'ABCDEFGHIJKLMNOPQRSTUVWXYZ') or ord(c) > 0x7F:
pos += 1
elif c == '\\' and not css.startswith('\\\n', pos):
# Valid escape
chunks.append(css[start_pos:pos])
c, pos = _consume_escape(css, pos + 1)
chunks.append(c)
start_pos = pos
else:
break
chunks.append(css[start_pos:pos])
return ''.join(chunks), pos
def _consume_quoted_string(css, pos):
"""Return (unescaped_value, new_pos)."""
# https://drafts.csswg.org/css-syntax/#consume-a-string-token
error = None
quote = css[pos]
assert quote in ('"', "'")
pos += 1
chunks = []
length = len(css)
start_pos = pos
while pos < length:
c = css[pos]
if c == quote:
chunks.append(css[start_pos:pos])
pos += 1
break
elif c == '\\':
chunks.append(css[start_pos:pos])
pos += 1
if pos < length:
if css[pos] == '\n': # Ignore escaped newlines
pos += 1
else:
c, pos = _consume_escape(css, pos)
chunks.append(c)
# else: Escaped EOF, do nothing
start_pos = pos
elif c == '\n': # Unescaped newline
return None, pos, ('bad-string', 'Bad string token')
else:
pos += 1
else:
error = ('eof-in-string', 'EOF in string')
chunks.append(css[start_pos:pos])
return ''.join(chunks), pos, error
def _consume_escape(css, pos):
r"""Return (unescaped_char, new_pos).
Assumes a valid escape: pos is just after '\' and not followed by '\n'.
"""
# https://drafts.csswg.org/css-syntax/#consume-an-escaped-character
hex_match = _HEX_ESCAPE_RE.match(css, pos)
if hex_match:
codepoint = int(hex_match.group(1), 16)
return (
chr(codepoint) if 0 < codepoint <= sys.maxunicode else '\uFFFD',
hex_match.end())
elif pos < len(css):
return css[pos], pos + 1
else:
return '\uFFFD', pos
def _consume_url(css, pos):
"""Return (unescaped_url, new_pos)
The given pos is assumed to be just after the '(' of 'url('.
"""
error = None
length = len(css)
# https://drafts.csswg.org/css-syntax/#consume-a-url-token
# Skip whitespace
while css.startswith((' ', '\n', '\t'), pos):
pos += 1
if pos >= length: # EOF
return '', pos, ('eof-in-url', 'EOF in URL')
c = css[pos]
if c in ('"', "'"):
value, pos, error = _consume_quoted_string(css, pos)
elif c == ')':
return '', pos + 1, error
else:
chunks = []
start_pos = pos
while 1:
if pos >= length: # EOF
chunks.append(css[start_pos:pos])
return ''.join(chunks), pos, ('eof-in-url', 'EOF in URL')
c = css[pos]
if c == ')':
chunks.append(css[start_pos:pos])
pos += 1
return ''.join(chunks), pos, error
elif c in ' \n\t':
chunks.append(css[start_pos:pos])
value = ''.join(chunks)
pos += 1
break
elif c == '\\' and not css.startswith('\\\n', pos):
# Valid escape
chunks.append(css[start_pos:pos])
c, pos = _consume_escape(css, pos + 1)
chunks.append(c)
start_pos = pos
elif (c in
'"\'('
# https://drafts.csswg.org/css-syntax/#non-printable-character
'\x00\x01\x02\x03\x04\x05\x06\x07\x08\x0b\x0e'
'\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19'
'\x1a\x1b\x1c\x1d\x1e\x1f\x7f'):
value = None # Parse error
pos += 1
break
else:
pos += 1
if value is not None:
while css.startswith((' ', '\n', '\t'), pos):
pos += 1
if pos < length:
if css[pos] == ')':
return value, pos + 1, error
else:
if error is None:
error = ('eof-in-url', 'EOF in URL')
return value, pos, error
# https://drafts.csswg.org/css-syntax/#consume-the-remnants-of-a-bad-url0
while pos < length:
if css.startswith('\\)', pos):
pos += 2
elif css[pos] == ')':
pos += 1
break
else:
pos += 1
return None, pos, ('bad-url', 'bad URL token')
def _consume_unicode_range(css, pos):
"""Return (range, new_pos)
The given pos is assume to be just after the '+' of 'U+' or 'u+'.
"""
# https://drafts.csswg.org/css-syntax/#consume-a-unicode-range-token
length = len(css)
start_pos = pos
max_pos = min(pos + 6, length)
while pos < max_pos and css[pos] in '0123456789abcdefABCDEF':
pos += 1
start = css[start_pos:pos]
start_pos = pos
# Same max_pos as before: total of hex digits and question marks <= 6
while pos < max_pos and css[pos] == '?':
pos += 1
question_marks = pos - start_pos
if question_marks:
end = start + 'F' * question_marks
start = start + '0' * question_marks
elif (pos + 1 < length and css[pos] == '-' and
css[pos + 1] in '0123456789abcdefABCDEF'):
pos += 1
start_pos = pos
max_pos = min(pos + 6, length)
while pos < max_pos and css[pos] in '0123456789abcdefABCDEF':
pos += 1
end = css[start_pos:pos]
else:
end = start
return int(start, 16), int(end, 16), pos
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