Memory and Performance Optimization

lib/css_parser.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'addressable/uri'
 require 'uri'
 require 'net/https'
@@ -122,10 +123,10 @@ def self.merge(*rule_sets)
   def self.calculate_specificity(selector)
     a = 0
     b = selector.scan(/\#/).length
-    c = selector.scan(NON_ID_ATTRIBUTES_AND_PSEUDO_CLASSES_RX).length
-    d = selector.scan(ELEMENTS_AND_PSEUDO_ELEMENTS_RX).length
+    c = selector.scan(NON_ID_ATTRIBUTES_AND_PSEUDO_CLASSES_RX_NC).length
+    d = selector.scan(ELEMENTS_AND_PSEUDO_ELEMENTS_RX_NC).length
 
-    (a.to_s + b.to_s + c.to_s + d.to_s).to_i
+    "#{a}#{b}#{c}#{d}".to_i
   rescue
     return 0
   end
@@ -160,7 +161,8 @@ def self.convert_uris(css, base_uri)
   end
 
   def self.sanitize_media_query(raw)
-    mq = raw.to_s.gsub(/[\s]+/, ' ').strip
+    mq = raw.to_s.gsub(/[\s]+/, ' ')
+    mq.strip!
     mq = 'all' if mq.empty?
     mq.to_sym
   end

lib/css_parser/parser.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module CssParser
   # Exception class used for any errors encountered while downloading remote files.
   class RemoteFileError < IOError; end
@@ -184,7 +185,8 @@ def add_rule_with_offsets!(selectors, declarations, filename, offset, media_type
     def add_rule_set!(ruleset, media_types = :all)
       raise ArgumentError unless ruleset.kind_of?(CssParser::RuleSet)
 
-      media_types = [media_types].flatten.collect { |mt| CssParser.sanitize_media_query(mt)}
+      media_types = [media_types] unless Array === media_types
+      media_types = media_types.flat_map { |mt| CssParser.sanitize_media_query(mt)}
 
       @rules << {:media_types => media_types, :rules => ruleset}
     end
@@ -253,7 +255,7 @@ def each_selector(all_media_types = :all, options = {}) # :yields: selectors, de
 
     # Output all CSS rules as a single stylesheet.
     def to_s(which_media = :all)
-      out = ''
+      out = String.new
       styles_by_media_types = {}
       each_selector(which_media) do |selectors, declarations, specificity, media_types|
         media_types.each do |media_type|
@@ -264,17 +266,17 @@ def to_s(which_media = :all)
 
       styles_by_media_types.each_pair do |media_type, media_styles|
         media_block = (media_type != :all)
-        out += "@media #{media_type} {\n" if media_block
+        out << "@media #{media_type} {\n" if media_block
 
         media_styles.each do |media_style|
           if media_block
-            out += "  #{media_style[0]} {\n    #{media_style[1]}\n  }\n"
+            out << "  #{media_style[0]} {\n    #{media_style[1]}\n  }\n"
           else
-            out += "#{media_style[0]} {\n#{media_style[1]}\n}\n"
+            out << "#{media_style[0]} {\n#{media_style[1]}\n}\n"
           end
         end
 
-        out += "}\n" if media_block
+        out << "}\n" if media_block
       end
 
       out
@@ -316,53 +318,52 @@ def parse_block_into_rule_sets!(block, options = {}) # :nodoc:
       in_at_media_rule = false
       in_media_block = false
 
-      current_selectors = ''
-      current_media_query = ''
-      current_declarations = ''
+      current_selectors = String.new
+      current_media_query = String.new
+      current_declarations = String.new
 
       # once we are in a rule, we will use this to store where we started if we are capturing offsets
       rule_start = nil
       offset = nil
 
-      block.scan(/(([\\]{2,})|([\\]?[{}\s"])|(.[^\s"{}\\]*))/) do |matches|
-        token = matches[0]
-
+      block.scan(/\s+|[\\]{2,}|[\\]?[{}\s"]|.[^\s"{}\\]*/) do |token|
         # save the regex offset so that we know where in the file we are
         offset = Regexp.last_match.offset(0) if options[:capture_offsets]
 
-        if token =~ /\A"/ # found un-escaped double quote
+        if token.start_with?('"') # found un-escaped double quote
           in_string = !in_string
         end
 
         if in_declarations > 0
           # too deep, malformed declaration block
           if in_declarations > 1
-            in_declarations -= 1 if token =~ /\}/
+            in_declarations -= 1 if token.include?('}')
             next
           end
 
-          if token =~ /\{/ and not in_string
+          if !in_string && token.include?('{')
             in_declarations += 1
             next
           end
 
-          current_declarations += token
+          current_declarations << token
 
-          if token =~ /\}/ and not in_string
+          if !in_string && token.include?('}')
             current_declarations.gsub!(/\}[\s]*$/, '')
 
             in_declarations -= 1
+            current_declarations.strip!
 
-            unless current_declarations.strip.empty?
+            unless current_declarations.empty?
               if options[:capture_offsets]
                 add_rule_with_offsets!(current_selectors, current_declarations, options[:filename], (rule_start..offset.last), current_media_queries)
               else
                 add_rule!(current_selectors, current_declarations, current_media_queries)
               end
             end
 
-            current_selectors = ''
-            current_declarations = ''
+            current_selectors = String.new
+            current_declarations = String.new
 
             # restart our search for selectors and declarations
             rule_start = nil if options[:capture_offsets]
@@ -372,26 +373,28 @@ def parse_block_into_rule_sets!(block, options = {}) # :nodoc:
           in_at_media_rule = true
           current_media_queries = []
         elsif in_at_media_rule
-          if token =~ /\{/
+          if token.include?('{')
             block_depth = block_depth + 1
             in_at_media_rule = false
             in_media_block = true
             current_media_queries << CssParser.sanitize_media_query(current_media_query)
-            current_media_query = ''
-          elsif token =~ /[,]/
+            current_media_query = String.new
+          elsif token.include?(',')
             # new media query begins
-            token.gsub!(/[,]/, ' ')
-            current_media_query += token.strip + ' '
+            token.tr!(',', ' ')
+            token.strip!
+            current_media_query << token << ' '
             current_media_queries << CssParser.sanitize_media_query(current_media_query)
-            current_media_query = ''
+            current_media_query = String.new
           else
-            current_media_query += token.strip + ' '
+            token.strip!
+            current_media_query << token << ' '
           end
         elsif in_charset or token =~ /@charset/i
           # iterate until we are out of the charset declaration
-          in_charset = (token =~ /;/ ? false : true)
+          in_charset = !token.include?(';')
         else
-          if token =~ /\}/ and not in_string
+          if !in_string && token.include?('}')
             block_depth = block_depth - 1
 
             # reset the current media query scope
@@ -400,12 +403,12 @@ def parse_block_into_rule_sets!(block, options = {}) # :nodoc:
               in_media_block = false
             end
           else
-            if token =~ /\{/ and not in_string
+            if !in_string && token.include?('{')
               current_selectors.strip!
               in_declarations += 1
             else
               # if we are in a selector, add the token to the current selectors
-              current_selectors += token
+              current_selectors << token
 
               # mark this as the beginning of the selector unless we have already marked it
               rule_start = offset.first if options[:capture_offsets] && rule_start.nil? && token =~ /^[^\s]+$/

lib/css_parser/regexps.rb

@@ -54,12 +54,12 @@ def self.regex_possible_values *values
 
 
   # Patterns for specificity calculations
-  NON_ID_ATTRIBUTES_AND_PSEUDO_CLASSES_RX= /
-    (\.[\w]+)                     # classes
+  NON_ID_ATTRIBUTES_AND_PSEUDO_CLASSES_RX_NC= /
+    (?:\.[\w]+)                     # classes
     |
-    \[(\w+)                       # attributes
+    \[(?:\w+)                       # attributes
     |
-    (\:(                          # pseudo classes
+    (?:\:(?:                          # pseudo classes
       link|visited|active
       |hover|focus
       |lang
@@ -72,10 +72,10 @@ def self.regex_possible_values *values
       |empty|contains
     ))
   /ix
-  ELEMENTS_AND_PSEUDO_ELEMENTS_RX = /
-    ((^|[\s\+\>\~]+)[\w]+       # elements
+  ELEMENTS_AND_PSEUDO_ELEMENTS_RX_NC = /
+    (?:(?:^|[\s\+\>\~]+)[\w]+       # elements
     |
-    \:{1,2}(                    # pseudo-elements
+    \:{1,2}(?:                    # pseudo-elements
       after|before
       |first-letter|first-line
       |selection

lib/css_parser/rule_set.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module CssParser
   class RuleSet
     # Patterns for specificity calculations
@@ -27,7 +28,7 @@ def get_value(property)
       return '' unless property and not property.empty?
 
       property = property.downcase.strip
-      properties = @declarations.inject('') do |val, (key, data)|
+      properties = @declarations.inject(String.new) do |val, (key, data)|
         #puts "COMPARING #{key} #{key.inspect} against #{property} #{property.inspect}"
         importance = data[:is_important] ? ' !important' : ''
         val << "#{data[:value]}#{importance}; " if key.downcase.strip == property
@@ -58,7 +59,8 @@ def add_declaration!(property, value)
 
       value.gsub!(/;\Z/, '')
       is_important = !value.gsub!(CssParser::IMPORTANT_IN_PROPERTY_RX, '').nil?
-      property = property.downcase.strip
+      property = property.downcase
+      property.strip!
       #puts "SAVING #{property}  #{value} #{is_important.inspect}"
       @declarations[property] = {
         :value => value, :is_important => is_important, :order => @order += 1
@@ -106,12 +108,14 @@ def each_declaration # :yields: property, value, is_important
     #++
     def declarations_to_s(options = {})
      options = {:force_important => false}.merge(options)
-     str = ''
+     str = String.new
      each_declaration do |prop, val, is_important|
        importance = (options[:force_important] || is_important) ? ' !important' : ''
-       str += "#{prop}: #{val}#{importance}; "
+       str << "#{prop}: #{val}#{importance}; "
      end
-     str.gsub(/^[\s^(\{)]+|[\n\r\f\t]*|[\s]+$/mx, '').strip
+     str.gsub!(/^[\s^(\{)]+|[\n\r\f\t]*|[\s]+$/mx, '')
+     str.strip!
+     str
     end
 
     # Return the CSS rule set as a string.
@@ -434,20 +438,20 @@ def create_font_shorthand! # :nodoc:
         return unless @declarations.has_key?(prop)
       end
 
-      new_value = ''
+      new_value = String.new
       ['font-style', 'font-variant', 'font-weight'].each do |property|
         unless @declarations[property][:value] == 'normal'
-          new_value += @declarations[property][:value] + ' '
+          new_value << @declarations[property][:value] << ' '
         end
       end
 
-      new_value += @declarations['font-size'][:value]
+      new_value << @declarations['font-size'][:value]
 
       unless @declarations['line-height'][:value] == 'normal'
-        new_value += '/' + @declarations['line-height'][:value]
+        new_value << '/' << @declarations['line-height'][:value]
       end
 
-      new_value += ' ' + @declarations['font-family'][:value]
+      new_value << ' ' << @declarations['font-family'][:value]
 
       @declarations['font'] = {:value => new_value.gsub(/[\s]+/, ' ').strip}
 
@@ -490,19 +494,18 @@ def parse_declarations!(block) # :nodoc:
 
       return unless block
 
-      block.gsub!(/(^[\s]*)|([\s]*$)/, '')
-
-      continuation = ''
+      continuation = nil
       block.split(/[\;$]+/m).each do |decs|
-        decs = continuation + decs
+        decs = continuation ? continuation + decs : decs
         if decs =~ /\([^)]*\Z/ # if it has an unmatched parenthesis
           continuation = decs + ';'
 
-        elsif matches = decs.match(/(.[^:]*)\s*:\s*(.+)(;?\s*\Z)/i)
-          property, value, = matches.captures # skip end_of_declaration
-
+        elsif matches = decs.match(/\s*(.[^:]*)\s*:\s*(.+?)(;?\s*\Z)/i)
+          # skip end_of_declaration
+          property = matches[1]
+          value = matches[2]
           add_declaration!(property, value)
-          continuation = ''
+          continuation = nil
         end
       end
     end
@@ -511,7 +514,11 @@ def parse_declarations!(block) # :nodoc:
     # TODO: way too simplistic
     #++
     def parse_selectors!(selectors) # :nodoc:
-      @selectors = selectors.split(',').map { |s| s.gsub(/\s+/, ' ').strip }
+      @selectors = selectors.split(',').map do |s|
+        s.gsub!(/\s+/, ' ')
+        s.strip!
+        s
+      end
     end
   end