Class: CssSplitter::Splitter

Inherits:
Object
  • Object
show all
Defined in:
lib/css_splitter/splitter.rb

Constant Summary collapse

MAX_SELECTORS_DEFAULT = 
4095

Class Method Summary collapse

Class Method Details

.count_selectors(css_file) ⇒ Object

count selectors of a CSS stylesheet (not used by SprocketsEngine)



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# File 'lib/css_splitter/splitter.rb', line 78

def self.count_selectors(css_file)
  raise "file could not be found" unless File.exists? css_file

  rules = split_string_into_rules(File.read css_file)
  return if rules.first.nil?

  rules.sum{ |rule| count_selectors_of_rule(rule) }
end

.count_selectors_of_rule(rule) ⇒ Object

count selectors of one individual CSS rule



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# File 'lib/css_splitter/splitter.rb', line 70

def self.count_selectors_of_rule(rule)
  parts = strip_comments(rule).partition(/\{/)
  parts.second.empty? ? 0 : parts.first.scan(/,/).count.to_i + 1
end

.extract_part(rules, part = 1, max_selectors = MAX_SELECTORS_DEFAULT) ⇒ Object

extracts the specified part of an overlong CSS string



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# File 'lib/css_splitter/splitter.rb', line 19

def self.extract_part(rules, part = 1, max_selectors = MAX_SELECTORS_DEFAULT)
  return if rules.first.nil?

  charset_statement, rules[0] = extract_charset(rules.first)
  return if rules.nil?

  output = charset_statement || ""
  selectors_count = 0
  selector_range = max_selectors * (part - 1) + 1 .. max_selectors * part # e.g (4096..8190)

  current_media = nil
  selectors_in_media = 0
  first_hit = true
  rules.each do |rule|
    media_part = extract_media(rule)
    if media_part
      current_media = media_part
      selectors_in_media = 0
    end

    rule_selectors_count = count_selectors_of_rule rule
    selectors_count += rule_selectors_count

    if rule =~ /\A\s*}\z$/
      current_media = nil
      # skip the line if the close bracket is the first rule for the new file
      next if first_hit
    end

    if selector_range.cover? selectors_count # add rule to current output if within selector_range
      if media_part
        output << media_part
      elsif first_hit && current_media
        output << current_media
      end
      selectors_in_media += rule_selectors_count if current_media.present?
      output << rule
      first_hit = false
    elsif selectors_count > selector_range.end # stop writing to output
      break
    end
  end

  if current_media.present? and selectors_in_media > 0
    output << '}'
  end

  output
end

.split_string(css_string, split = 1, max_selectors = MAX_SELECTORS_DEFAULT) ⇒ Object

returns the specified split of the passed css_string



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# File 'lib/css_splitter/splitter.rb', line 8

def self.split_string(css_string, split = 1, max_selectors = MAX_SELECTORS_DEFAULT)
  rules = split_string_into_rules(css_string)
  extract_part rules, split, max_selectors
end

.split_string_into_rules(css_string) ⇒ Object

splits string into array of rules (also strips comments)



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# File 'lib/css_splitter/splitter.rb', line 14

def self.split_string_into_rules(css_string)
  strip_comments(css_string).chomp.scan /[^}]*}/
end