Module: CssParser

Defined in:
lib/css_parser.rb,
lib/css_parser/parser.rb,
lib/css_parser/regexps.rb,
lib/css_parser/version.rb,
lib/css_parser/rule_set.rb

Defined Under Namespace

Classes: CircularReferenceError, Parser, RemoteFileError, RuleSet

Constant Summary collapse

RE_NL =

:stopdoc: Base types

Regexp.new('(\n|\r\n|\r|\f)')
RE_NON_ASCII =
^0-177 
Regexp.new('([\x00-\xFF])', Regexp::IGNORECASE | Regexp::NOENCODING)
RE_UNICODE = 
Regexp.new('(\\\\[0-9a-f]{1,6}(\r\n|[ \n\r\t\f])*)', Regexp::IGNORECASE | Regexp::EXTENDED | Regexp::MULTILINE | Regexp::NOENCODING)
RE_ESCAPE = 
Regexp.union(RE_UNICODE, '|(\\\\[^\n\r\f0-9a-f])')
RE_IDENT = 
Regexp.new("[-]?([_a-z]|#{RE_NON_ASCII}|#{RE_ESCAPE})([_a-z0-9-]|#{RE_NON_ASCII}|#{RE_ESCAPE})*", Regexp::IGNORECASE | Regexp::NOENCODING)
RE_STRING1 =

General strings

/("(.[^\n\r\f"]*|\\#{RE_NL}|#{RE_ESCAPE})*")/.freeze
RE_STRING2 = 
/('(.[^\n\r\f']*|\\#{RE_NL}|#{RE_ESCAPE})*')/.freeze
RE_STRING = 
Regexp.union(RE_STRING1, RE_STRING2)
RE_INHERIT = 
regex_possible_values 'inherit'
RE_URI = 
/(url\(\s*(\s*#{RE_STRING}\s*)\s*\))|(url\(\s*([!#$%&*\-~]|#{RE_NON_ASCII}|#{RE_ESCAPE})*\s*)\)/ixm.freeze
URI_RX = 
/url\(("([^"]*)"|'([^']*)'|([^)]*))\)/im.freeze
URI_RX_OR_NONE = 
Regexp.union(URI_RX, /none/i)
RE_GRADIENT = 
/[-a-z]*gradient\([-a-z0-9 .,#%()]*\)/im.freeze
RE_AT_IMPORT_RULE =

Initial parsing

/@import\s+(url\()?["']?(.[^'"\s]*)["']?\)?([\w\s,^\])]*)\)?;?/.freeze
IMPORTANT_IN_PROPERTY_RX =

RE_AT_IMPORT_RULE = Regexp.new(‘@import*(’ + RE_STRING.to_s + ‘)([ws,]*)?’, Regexp::IGNORECASE) – should handle url() even though it is not allowed ++

/\s*!important\b\s*/i.freeze
RE_INSIDE_OUTSIDE = 
regex_possible_values 'inside', 'outside'
RE_SCROLL_FIXED = 
regex_possible_values 'scroll', 'fixed'
RE_REPEAT = 
regex_possible_values 'repeat(\-x|\-y)*|no\-repeat'
RE_LIST_STYLE_TYPE = 
regex_possible_values(
  'disc', 'circle', 'square', 'decimal-leading-zero', 'decimal', 'lower-roman',
  'upper-roman', 'lower-greek', 'lower-alpha', 'lower-latin', 'upper-alpha',
  'upper-latin', 'hebrew', 'armenian', 'georgian', 'cjk-ideographic', 'hiragana',
  'hira-gana-iroha', 'katakana-iroha', 'katakana', 'none'
)
RE_IMAGE = 
Regexp.union(CssParser::URI_RX, CssParser::RE_GRADIENT, /none/i)
STRIP_CSS_COMMENTS_RX = 
%r{/\*.*?\*/}m.freeze
STRIP_HTML_COMMENTS_RX = 
/<!--|-->/m.freeze
BOX_MODEL_UNITS_RX =

Special units

/(auto|inherit|0|(-*([0-9]+|[0-9]*\.[0-9]+)(rem|vw|vh|vm|vmin|vmax|e[mx]+|px|[cm]+m|p[tc+]|in|%)))([\s;]|\Z)/imx.freeze
RE_LENGTH_OR_PERCENTAGE = 
Regexp.new('([\-]*(([0-9]*\.[0-9]+)|[0-9]+)(e[mx]+|px|[cm]+m|p[tc+]|in|\%))', Regexp::IGNORECASE)
RE_SINGLE_BACKGROUND_POSITION = 
/#{RE_LENGTH_OR_PERCENTAGE}|left|center|right|top|bottom/i.freeze
RE_SINGLE_BACKGROUND_SIZE = 
/#{RE_LENGTH_OR_PERCENTAGE}|auto|cover|contain|initial|inherit/i.freeze
RE_BACKGROUND_POSITION = 
/#{RE_SINGLE_BACKGROUND_POSITION}\s+#{RE_SINGLE_BACKGROUND_POSITION}|#{RE_SINGLE_BACKGROUND_POSITION}/.freeze
RE_BACKGROUND_SIZE = 
%r{\s*/\s*(#{RE_SINGLE_BACKGROUND_SIZE}\s+#{RE_SINGLE_BACKGROUND_SIZE}|#{RE_SINGLE_BACKGROUND_SIZE})}.freeze
FONT_UNITS_RX = 
/((x+-)*small|medium|larger*|auto|inherit|([0-9]+|[0-9]*\.[0-9]+)(e[mx]+|px|[cm]+m|p[tc+]|in|%)*)/i.freeze
RE_BORDER_STYLE = 
/(\s*^)?(none|hidden|dotted|dashed|solid|double|dot-dash|dot-dot-dash|wave|groove|ridge|inset|outset)(\s*$)?/imx.freeze
RE_BORDER_UNITS = 
Regexp.union(BOX_MODEL_UNITS_RX, /(thin|medium|thick)/i)
RE_FUNCTIONS =

Functions like calc, var, clamp, etc.

/
  (
    [a-z0-9-]+        # function name
  )
  (?>
    \(                # opening parenthesis
      (?:
        ([^()]+)
        |             # recursion via subexpression
        \g<0>
      )*
    \)                # closing parenthesis
  )
/imx.freeze
NON_ID_ATTRIBUTES_AND_PSEUDO_CLASSES_RX_NC =

Patterns for specificity calculations

/
  (?:\.\w+)                     # classes
  |
  \[(?:\w+)                       # attributes
  |
  (?::(?:                          # pseudo classes
    link|visited|active
    |hover|focus
    |lang
    |target
    |enabled|disabled|checked|indeterminate
    |root
    |nth-child|nth-last-child|nth-of-type|nth-last-of-type
    |first-child|last-child|first-of-type|last-of-type
    |only-child|only-of-type
    |empty|contains
  ))
/ix.freeze
ELEMENTS_AND_PSEUDO_ELEMENTS_RX_NC = 
/
  (?:(?:^|[\s+>~]+)\w+       # elements
  |
  :{1,2}(?:                    # pseudo-elements
    after|before
    |first-letter|first-line
    |selection
  )
)/ix.freeze
NAMED_COLOURS =

Colours

%w[
  aliceblue
  antiquewhite
  aqua
  aquamarine
  azure
  beige
  bisque
  black
  blanchedalmond
  blue
  blueviolet
  brown
  burlywood
  cadetblue
  chartreuse
  chocolate
  coral
  cornflowerblue
  cornsilk
  crimson
  cyan
  darkblue
  darkcyan
  darkgoldenrod
  darkgray
  darkgreen
  darkgrey
  darkkhaki
  darkmagenta
  darkolivegreen
  darkorange
  darkorchid
  darkred
  darksalmon
  darkseagreen
  darkslateblue
  darkslategray
  darkslategrey
  darkturquoise
  darkviolet
  deeppink
  deepskyblue
  dimgray
  dimgrey
  dodgerblue
  firebrick
  floralwhite
  forestgreen
  fuchsia
  gainsboro
  ghostwhite
  gold
  goldenrod
  gray
  green
  greenyellow
  grey
  honeydew
  hotpink
  indianred
  indigo
  ivory
  khaki
  lavender
  lavenderblush
  lawngreen
  lemonchiffon
  lightblue
  lightcoral
  lightcyan
  lightgoldenrodyellow
  lightgray
  lightgreen
  lightgrey
  lightpink
  lightsalmon
  lightseagreen
  lightskyblue
  lightslategray
  lightslategrey
  lightsteelblue
  lightyellow
  lime
  limegreen
  linen
  magenta
  maroon
  mediumaquamarine
  mediumblue
  mediumorchid
  mediumpurple
  mediumseagreen
  mediumslateblue
  mediumspringgreen
  mediumturquoise
  mediumvioletred
  midnightblue
  mintcream
  mistyrose
  moccasin
  navajowhite
  navy
  oldlace
  olive
  olivedrab
  orange
  orangered
  orchid
  palegoldenrod
  palegreen
  paleturquoise
  palevioletred
  papayawhip
  peachpuff
  peru
  pink
  plum
  powderblue
  purple
  red
  rosybrown
  royalblue
  saddlebrown
  salmon
  sandybrown
  seagreen
  seashell
  sienna
  silver
  skyblue
  slateblue
  slategray
  slategrey
  snow
  springgreen
  steelblue
  tan
  teal
  thistle
  tomato
  turquoise
  violet
  wheat
  white
  whitesmoke
  yellow
  yellowgreen

  transparent
  inherit
  currentColor
].freeze
RE_COLOUR_NUMERIC = 
/\b(hsl|rgb)\s*\(-?\s*-?\d+(\.\d+)?%?\s*%?,-?\s*-?\d+(\.\d+)?%?\s*%?,-?\s*-?\d+(\.\d+)?%?\s*%?\)/i.freeze
RE_COLOUR_NUMERIC_ALPHA = 
/\b(hsla|rgba)\s*\(-?\s*-?\d+(\.\d+)?%?\s*%?,-?\s*-?\d+(\.\d+)?%?\s*%?,-?\s*-?\d+(\.\d+)?%?\s*%?,-?\s*-?\d+(\.\d+)?%?\s*%?\)/i.freeze
RE_COLOUR_HEX = 
/\s*#([0-9a-fA-F]{6}|[0-9a-fA-F]{3})\b/.freeze
RE_COLOUR_NAMED = 
/\s*\b(#{NAMED_COLOURS.join('|')})\b/i.freeze
RE_COLOUR = 
Regexp.union(RE_COLOUR_NUMERIC, RE_COLOUR_NUMERIC_ALPHA, RE_COLOUR_HEX, RE_COLOUR_NAMED)
VERSION = 
'1.19.1'.freeze

Class Method Summary collapse

Class Method Details

.calculate_specificity(selector) ⇒ Object

Calculates the specificity of a CSS selector per www.w3.org/TR/CSS21/cascade.html#specificity

Returns an integer.

Example

CssParser.calculate_specificity('#content div p:first-line a:link')
=> 114

– Thanks to Rafael Salazar and Nick Fitzsimons on the css-discuss list for their help. ++



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# File 'lib/css_parser.rb', line 112

def self.calculate_specificity(selector)
  a = 0
  b = selector.scan('#').length
  c = selector.scan(NON_ID_ATTRIBUTES_AND_PSEUDO_CLASSES_RX_NC).length
  d = selector.scan(ELEMENTS_AND_PSEUDO_ELEMENTS_RX_NC).length

  "#{a}#{b}#{c}#{d}".to_i
rescue
  0
end

.convert_uris(css, base_uri) ⇒ Object

Make url() links absolute.

Takes a block of CSS and returns it with all relative URIs converted to absolute URIs.

“For CSS style sheets, the base URI is that of the style sheet, not that of the source document.” per www.w3.org/TR/CSS21/syndata.html#uri

Returns a string.

Example

CssParser.convert_uris("body { background: url('../style/yellow.png?abc=123') };",
             "http://example.org/style/basic.css").inspect
=> "body { background: url('http://example.org/style/yellow.png?abc=123') };"



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# File 'lib/css_parser.rb', line 136

def self.convert_uris(css, base_uri)
  base_uri = Addressable::URI.parse(base_uri) unless base_uri.is_a?(Addressable::URI)

  css.gsub(URI_RX) do
    uri = Regexp.last_match(1).to_s.gsub(/["']+/, '')
    # Don't process URLs that are already absolute
    unless uri.match(%r{^[a-z]+://}i)
      begin
        uri = base_uri.join(uri)
      rescue
        nil
      end
    end
    "url('#{uri}')"
  end
end

.merge(*rule_sets) ⇒ Object

Merge multiple CSS RuleSets by cascading according to the CSS 2.1 cascading rules (www.w3.org/TR/REC-CSS2/cascade.html#cascading-order).

Takes one or more RuleSet objects.

Returns a RuleSet.

Cascading

If a RuleSet object has its specificity defined, that specificity is used in the cascade calculations.

If no specificity is explicitly set and the RuleSet has one selector, the specificity is calculated using that selector.

If no selectors the specificity is treated as 0.

If multiple selectors are present then the greatest specificity is used.

Example #1

rs1 = RuleSet.new(nil, 'color: black;')
rs2 = RuleSet.new(nil, 'margin: 0px;')

merged = CssParser.merge(rs1, rs2)

puts merged
=> "{ margin: 0px; color: black; }"

Example #2

rs1 = RuleSet.new(nil, 'background-color: black;')
rs2 = RuleSet.new(nil, 'background-image: none;')

merged = CssParser.merge(rs1, rs2)

puts merged
=> "{ background: none black; }"

– TODO: declaration_hashes should be able to contain a RuleSet

this should be a Class method



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# File 'lib/css_parser.rb', line 55

def self.merge(*rule_sets)
  @folded_declaration_cache = {}

  # in case called like CssParser.merge([rule_set, rule_set])
  rule_sets.flatten! if rule_sets[0].is_a?(Array)

  unless rule_sets.all? { |rs| rs.is_a?(CssParser::RuleSet) }
    raise ArgumentError, 'all parameters must be CssParser::RuleSets.'
  end

  return rule_sets[0] if rule_sets.length == 1

  # Internal storage of CSS properties that we will keep
  properties = {}

  rule_sets.each do |rule_set|
    rule_set.expand_shorthand!

    specificity = rule_set.specificity
    specificity ||= rule_set.selectors.map { |s| calculate_specificity(s) }.compact.max || 0

    rule_set.each_declaration do |property, value, is_important|
      # Add the property to the list to be folded per http://www.w3.org/TR/CSS21/cascade.html#cascading-order
      if !properties.key?(property)
        properties[property] = {value: value, specificity: specificity, is_important: is_important}
      elsif is_important
        if !properties[property][:is_important] || properties[property][:specificity] <= specificity
          properties[property] = {value: value, specificity: specificity, is_important: is_important}
        end
      elsif properties[property][:specificity] < specificity || properties[property][:specificity] == specificity
        unless properties[property][:is_important]
          properties[property] = {value: value, specificity: specificity, is_important: is_important}
        end
      end
    end
  end

  merged = properties.each_with_object(RuleSet.new(nil, nil)) do |(property, details), rule_set|
    value = details[:value].strip
    rule_set[property.strip] = details[:is_important] ? "#{value.gsub(/;\Z/, '')}!important" : value
  end

  merged.create_shorthand!
  merged
end

.regex_possible_values(*values) ⇒ Object 



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# File 'lib/css_parser/regexps.rb', line 4

def self.regex_possible_values(*values)
  Regexp.new("([\s]*^)?(#{values.join('|')})([\s]*$)?", 'i')
end

.sanitize_media_query(raw) ⇒ Object 



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# File 'lib/css_parser.rb', line 153

def self.sanitize_media_query(raw)
  mq = raw.to_s.gsub(/\s+/, ' ')
  mq.strip!
  mq = 'all' if mq.empty?
  mq.to_sym
end