Module rcssmin

# Source Code for Module rcssmin

      1  #!/usr/bin/env python
      2  # -*- coding: ascii -*-
      3  r"""
      4  ==============
      5   CSS Minifier
      6  ==============
      7
      8  CSS Minifier.
      9
     10  The minifier is based on the semantics of the `YUI compressor`_\\, which
     11  itself is based on `the rule list by Isaac Schlueter`_\\.
     12
     13  :Copyright:
     14
     15   Copyright 2011 - 2015
     16   Andr\xe9 Malo or his licensors, as applicable
     17
     18  :License:
     19
     20   Licensed under the Apache License, Version 2.0 (the "License");
     21   you may not use this file except in compliance with the License.
     22   You may obtain a copy of the License at
     23
     24       http://www.apache.org/licenses/LICENSE-2.0
     25
     26   Unless required by applicable law or agreed to in writing, software
     27   distributed under the License is distributed on an "AS IS" BASIS,
     28   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     29   See the License for the specific language governing permissions and
     30   limitations under the License.
     31
     32  This module is a re-implementation aiming for speed instead of maximum
     33  compression, so it can be used at runtime (rather than during a preprocessing
     34  step). RCSSmin does syntactical compression only (removing spaces, comments
     35  and possibly semicolons). It does not provide semantic compression (like
     36  removing empty blocks, collapsing redundant properties etc). It does, however,
     37  support various CSS hacks (by keeping them working as intended).
     38
     39  Here's a feature list:
     40
     41  - Strings are kept, except that escaped newlines are stripped
     42  - Space/Comments before the very end or before various characters are
     43    stripped: ``:{});=>],!`` (The colon (``:``) is a special case, a single
     44    space is kept if it's outside a ruleset.)
     45  - Space/Comments at the very beginning or after various characters are
     46    stripped: ``{}(=:>[,!``
     47  - Optional space after unicode escapes is kept, resp. replaced by a simple
     48    space
     49  - whitespaces inside ``url()`` definitions are stripped
     50  - Comments starting with an exclamation mark (``!``) can be kept optionally.
     51  - All other comments and/or whitespace characters are replaced by a single
     52    space.
     53  - Multiple consecutive semicolons are reduced to one
     54  - The last semicolon within a ruleset is stripped
     55  - CSS Hacks supported:
     56
     57    - IE7 hack (``>/**/``)
     58    - Mac-IE5 hack (``/*\\*/.../**/``)
     59    - The boxmodelhack is supported naturally because it relies on valid CSS2
     60      strings
     61    - Between ``:first-line`` and the following comma or curly brace a space is
     62      inserted. (apparently it's needed for IE6)
     63    - Same for ``:first-letter``
     64
     65  rcssmin.c is a reimplementation of rcssmin.py in C and improves runtime up to
     66  factor 100 or so (depending on the input). docs/BENCHMARKS in the source
     67  distribution contains the details.
     68
     69  Both python 2 (>= 2.4) and python 3 are supported.
     70
     71  .. _YUI compressor: https://github.com/yui/yuicompressor/
     72
     73  .. _the rule list by Isaac Schlueter: https://github.com/isaacs/cssmin/
     74  """
     75  if __doc__:
     76      # pylint: disable = W0622
     77      __doc__ = __doc__.encode('ascii').decode('unicode_escape')
     78  __author__ = r"Andr\xe9 Malo".encode('ascii').decode('unicode_escape')
     79  __docformat__ = "restructuredtext en"
     80  __license__ = "Apache License, Version 2.0"
     81  __version__ = '1.0.6'
     82  __all__ = ['cssmin']
     83
     84  import re as _re
     85
     86
     87 -def _make_cssmin(python_only=False):
     88      """
     89      Generate CSS minifier.
     90
     91      :Parameters:
     92        `python_only` : ``bool``
     93          Use only the python variant. If true, the c extension is not even
     94          tried to be loaded.
     95
     96      :Return: Minifier
     97      :Rtype: ``callable``
     98      """
     99      # pylint: disable = R0912, R0914, W0612
    100
    101      if not python_only:
    102          try:
    103              import _rcssmin
    104          except ImportError:
    105              pass
    106          else:
    107              return _rcssmin.cssmin
    108
    109      nl = r'(?:[\n\f]|\r\n?)'  # pylint: disable = C0103
    110      spacechar = r'[\r\n\f\040\t]'
    111
    112      unicoded = r'[0-9a-fA-F]{1,6}(?:[\040\n\t\f]|\r\n?)?'
    113      escaped = r'[^\n\r\f0-9a-fA-F]'
    114      escape = r'(?:\\(?:%(unicoded)s|%(escaped)s))' % locals()
    115
    116      nmchar = r'[^\000-\054\056\057\072-\100\133-\136\140\173-\177]'
    117      # nmstart = r'[^\000-\100\133-\136\140\173-\177]'
    118      # ident = (r'(?:'
    119      #     r'-?(?:%(nmstart)s|%(escape)s)%(nmchar)s*(?:%(escape)s%(nmchar)s*)*'
    120      # r')') % locals()
    121
    122      comment = r'(?:/\*[^*]*\*+(?:[^/*][^*]*\*+)*/)'
    123
    124      # only for specific purposes. The bang is grouped:
    125      _bang_comment = r'(?:/\*(!?)[^*]*\*+(?:[^/*][^*]*\*+)*/)'
    126
    127      string1 = \
    128          r'(?:\047[^\047\\\r\n\f]*(?:\\[^\r\n\f][^\047\\\r\n\f]*)*\047)'
    129      string2 = r'(?:"[^"\\\r\n\f]*(?:\\[^\r\n\f][^"\\\r\n\f]*)*")'
    130      strings = r'(?:%s|%s)' % (string1, string2)
    131
    132      nl_string1 = \
    133          r'(?:\047[^\047\\\r\n\f]*(?:\\(?:[^\r]|\r\n?)[^\047\\\r\n\f]*)*\047)'
    134      nl_string2 = r'(?:"[^"\\\r\n\f]*(?:\\(?:[^\r]|\r\n?)[^"\\\r\n\f]*)*")'
    135      nl_strings = r'(?:%s|%s)' % (nl_string1, nl_string2)
    136
    137      uri_nl_string1 = r'(?:\047[^\047\\]*(?:\\(?:[^\r]|\r\n?)[^\047\\]*)*\047)'
    138      uri_nl_string2 = r'(?:"[^"\\]*(?:\\(?:[^\r]|\r\n?)[^"\\]*)*")'
    139      uri_nl_strings = r'(?:%s|%s)' % (uri_nl_string1, uri_nl_string2)
    140
    141      nl_escaped = r'(?:\\%(nl)s)' % locals()
    142
    143      space = r'(?:%(spacechar)s|%(comment)s)' % locals()
    144
    145      ie7hack = r'(?:>/\*\*/)'
    146
    147      uri = (r'(?:'
    148          # noqa pylint: disable = C0330
    149          r'(?:[^\000-\040"\047()\\\177]*'
    150              r'(?:%(escape)s[^\000-\040"\047()\\\177]*)*)'
    151          r'(?:'
    152              r'(?:%(spacechar)s+|%(nl_escaped)s+)'
    153              r'(?:'
    154                  r'(?:[^\000-\040"\047()\\\177]|%(escape)s|%(nl_escaped)s)'
    155                  r'[^\000-\040"\047()\\\177]*'
    156                  r'(?:%(escape)s[^\000-\040"\047()\\\177]*)*'
    157              r')+'
    158          r')*'
    159      r')') % locals()
    160
    161      nl_unesc_sub = _re.compile(nl_escaped).sub
    162
    163      uri_space_sub = _re.compile((
    164          r'(%(escape)s+)|%(spacechar)s+|%(nl_escaped)s+'
    165      ) % locals()).sub
    166      uri_space_subber = lambda m: m.groups()[0] or ''
    167
    168      space_sub_simple = _re.compile((
    169          r'[\r\n\f\040\t;]+|(%(comment)s+)'
    170      ) % locals()).sub
    171      space_sub_banged = _re.compile((
    172          r'[\r\n\f\040\t;]+|(%(_bang_comment)s+)'
    173      ) % locals()).sub
    174
    175      post_esc_sub = _re.compile(r'[\r\n\f\t]+').sub
    176
    177      main_sub = _re.compile((
    178          # noqa pylint: disable = C0330
    179          r'([^\\"\047u>@\r\n\f\040\t/;:{}+]+)'             # 1
    180          r'|(?<=[{}(=:>[,!])(%(space)s+)'                  # 2
    181          r'|^(%(space)s+)'                                 # 3
    182          r'|(%(space)s+)(?=(([:{});=>\],!])|$)?)'          # 4, 5, 6
    183          r'|;(%(space)s*(?:;%(space)s*)*)(?=(\})?)'        # 7, 8
    184          r'|(\{)'                                          # 9
    185          r'|(\})'                                          # 10
    186          r'|(%(strings)s)'                                 # 11
    187          r'|(?<!%(nmchar)s)url\(%(spacechar)s*('           # 12
    188                  r'%(uri_nl_strings)s'
    189                  r'|%(uri)s'
    190              r')%(spacechar)s*\)'
    191          r'|(@(?:'                                         # 13
    192                r'[mM][eE][dD][iI][aA]'
    193                r'|[sS][uU][pP][pP][oO][rR][tT][sS]'
    194                r'|[dD][oO][cC][uU][mM][eE][nN][tT]'
    195                r'|(?:-(?:'
    196                    r'[wW][eE][bB][kK][iI][tT]|[mM][oO][zZ]|[oO]|[mM][sS]'
    197                  r')-)?'
    198                  r'[kK][eE][yY][fF][rR][aA][mM][eE][sS]'
    199              r'))(?!%(nmchar)s)'
    200          r'|(%(ie7hack)s)(%(space)s*)'                     # 14, 15
    201          r'|(:[fF][iI][rR][sS][tT]-[lL]'                   # 16
    202              r'(?:[iI][nN][eE]|[eE][tT][tT][eE][rR]))'
    203              r'(%(space)s*)(?=[{,])'                       # 17
    204          r'|(%(nl_strings)s)'                              # 18
    205          r'|(%(escape)s[^\\"\047u>@\r\n\f\040\t/;:{}+]*)'  # 19
    206      ) % locals()).sub
    207
    208      # print main_sub.__self__.pattern
    209
    210      def main_subber(keep_bang_comments):
    211          """ Make main subber """
    212          in_macie5, in_rule, at_group = [0], [0], [0]
    213
    214          if keep_bang_comments:
    215              space_sub = space_sub_banged
    216
    217              def space_subber(match):
    218                  """ Space|Comment subber """
    219                  if match.lastindex:
    220                      group1, group2 = match.group(1, 2)
    221                      if group2:
    222                          if group1.endswith(r'\*/'):
    223                              in_macie5[0] = 1
    224                          else:
    225                              in_macie5[0] = 0
    226                          return group1
    227                      elif group1:
    228                          if group1.endswith(r'\*/'):
    229                              if in_macie5[0]:
    230                                  return ''
    231                              in_macie5[0] = 1
    232                              return r'/*\*/'
    233                          elif in_macie5[0]:
    234                              in_macie5[0] = 0
    235                              return '/**/'
    236                  return ''
    237          else:
    238              space_sub = space_sub_simple
    239
    240              def space_subber(match):
    241                  """ Space|Comment subber """
    242                  if match.lastindex:
    243                      if match.group(1).endswith(r'\*/'):
    244                          if in_macie5[0]:
    245                              return ''
    246                          in_macie5[0] = 1
    247                          return r'/*\*/'
    248                      elif in_macie5[0]:
    249                          in_macie5[0] = 0
    250                          return '/**/'
    251                  return ''
    252
    253          def fn_space_post(group):
    254              """ space with token after """
    255              if group(5) is None or (
    256                      group(6) == ':' and not in_rule[0] and not at_group[0]):
    257                  return ' ' + space_sub(space_subber, group(4))
    258              return space_sub(space_subber, group(4))
    259
    260          def fn_semicolon(group):
    261              """ ; handler """
    262              return ';' + space_sub(space_subber, group(7))
    263
    264          def fn_semicolon2(group):
    265              """ ; handler """
    266              if in_rule[0]:
    267                  return space_sub(space_subber, group(7))
    268              return ';' + space_sub(space_subber, group(7))
    269
    270          def fn_open(_):
    271              """ { handler """
    272              if at_group[0]:
    273                  at_group[0] -= 1
    274              else:
    275                  in_rule[0] = 1
    276              return '{'
    277
    278          def fn_close(_):
    279              """ } handler """
    280              in_rule[0] = 0
    281              return '}'
    282
    283          def fn_at_group(group):
    284              """ @xxx group handler """
    285              at_group[0] += 1
    286              return group(13)
    287
    288          def fn_ie7hack(group):
    289              """ IE7 Hack handler """
    290              if not in_rule[0] and not at_group[0]:
    291                  in_macie5[0] = 0
    292                  return group(14) + space_sub(space_subber, group(15))
    293              return '>' + space_sub(space_subber, group(15))
    294
    295          table = (
    296              # noqa pylint: disable = C0330
    297              None,
    298              None,
    299              None,
    300              None,
    301              fn_space_post,                       # space with token after
    302              fn_space_post,                       # space with token after
    303              fn_space_post,                       # space with token after
    304              fn_semicolon,                        # semicolon
    305              fn_semicolon2,                       # semicolon
    306              fn_open,                             # {
    307              fn_close,                            # }
    308              lambda g: g(11),                     # string
    309              lambda g: 'url(%s)' % uri_space_sub(uri_space_subber, g(12)),
    310                                                   # url(...)
    311              fn_at_group,                         # @xxx expecting {...}
    312              None,
    313              fn_ie7hack,                          # ie7hack
    314              None,
    315              lambda g: g(16) + ' ' + space_sub(space_subber, g(17)),
    316                                                   # :first-line|letter followed
    317                                                   # by [{,] (apparently space
    318                                                   # needed for IE6)
    319              lambda g: nl_unesc_sub('', g(18)),   # nl_string
    320              lambda g: post_esc_sub(' ', g(19)),  # escape
    321          )
    322
    323          def func(match):
    324              """ Main subber """
    325              idx, group = match.lastindex, match.group
    326              if idx > 3:
    327                  return table[idx](group)
    328
    329              # shortcuts for frequent operations below:
    330              elif idx == 1:     # not interesting
    331                  return group(1)
    332              # else: # space with token before or at the beginning
    333              return space_sub(space_subber, group(idx))
    334
    335          return func
    336
    337      def cssmin(style, keep_bang_comments=False):  # pylint: disable = W0621
    338          """
    339          Minify CSS.
    340
    341          :Parameters:
    342            `style` : ``str``
    343              CSS to minify
    344
    345            `keep_bang_comments` : ``bool``
    346              Keep comments starting with an exclamation mark? (``/*!...*/``)
    347
    348          :Return: Minified style
    349          :Rtype: ``str``
    350          """
    351          return main_sub(main_subber(keep_bang_comments), style)
    352
    353      return cssmin
    354
    355  cssmin = _make_cssmin()
    356
    357
    358  if __name__ == '__main__':
    359 -    def main():
    360          """ Main """
    361          import sys as _sys
    362          keep_bang_comments = (
    363              '-b' in _sys.argv[1:]
    364              or '-bp' in _sys.argv[1:]
    365              or '-pb' in _sys.argv[1:]
    366          )
    367          if '-p' in _sys.argv[1:] or '-bp' in _sys.argv[1:] \
    368                  or '-pb' in _sys.argv[1:]:
    369              global cssmin  # pylint: disable = W0603
    370              cssmin = _make_cssmin(python_only=True)
    371          _sys.stdout.write(cssmin(
    372              _sys.stdin.read(), keep_bang_comments=keep_bang_comments
    373          ))
    374      main()
    375