Improve core CSS parser.

.rubocop.yml

@@ -1,5 +1,5 @@
 AllCops:
-  TargetRubyVersion: 2.4  # lowest supported version
+  TargetRubyVersion: 2.5  # lowest supported version
   NewCops: enable
 
 Layout/ArgumentAlignment:

css_parser.gemspec

@@ -11,7 +11,7 @@ Gem::Specification.new name, CssParser::VERSION do |s|
   s.author = 'Alex Dunae'
   s.files = Dir.glob('lib/**/*') + ['MIT-LICENSE']
   s.license = 'MIT'
-  s.required_ruby_version = '>= 2.4'
+  s.required_ruby_version = '>= 2.5'
 
   s.metadata['changelog_uri'] = 'https://github.com/premailer/css_parser/blob/master/CHANGELOG.md'
   s.metadata['source_code_uri'] = 'https://github.com/premailer/css_parser'

lib/css_parser/parser.rb

@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require_relative 'parser/parser'
+
 module CssParser
   # Exception class used for any errors encountered while downloading remote files.
   class RemoteFileError < IOError; end

lib/css_parser/parser/parser.rb

@@ -0,0 +1,124 @@
+# frozen_string_literal: true
+
+module CssParser
+  class Parser
+    module Parser
+      def self.parse(css)
+        puts css
+
+        rules = []
+        scanner = StringScanner.new(css)
+
+        until scanner.eos?
+          rule = {
+            selector: '',
+            properties: ''
+          }
+          scanner.skip(/\s*/)
+          rule[:selector] = parse_selector(scanner).strip
+          rule[:properties] = parse_proppertied(scanner).strip
+
+          rules << rule
+          puts "pushing rule #{rule.inspect}"
+          scanner.skip(/\s*/)
+        end
+
+        rules
+      end
+
+      def self.parse_string(scanner, quote)
+        quoted_string = ''
+        string_ended = false
+
+        until string_ended
+          selector = scanner.scan_until(/#{quote}/)
+          quoted_string += selector
+          backslashes = /\\*\z/.match(selector[0..-2])[0].length
+          string_ended = backslashes.even?
+        end
+
+        quoted_string.gsub(/\\{2}/, '\\')
+      end
+
+      def self.parse_selector(scanner)
+        new_selector = ''
+        got_to_properties = false
+
+        until got_to_properties
+          selector = scanner.scan_until(/'|"|{|\\{2}/)
+          case scanner[0]
+          when nil
+            raise 'CSS invalid stylesheet, could not find end of selector'
+          when '\\\\' # maybe this can be replaced with a gsub at the end .tr("\\\\", "\\")
+            new_selector += selector[0..(- 1 - scanner[0].length)]
+            # if you have two backslashes the selector should have one
+            new_selector += '\\'
+
+          when '"', "'"
+            backslashes = /\\*\z/.match(selector[0..-2])[0].length
+            case backslashes
+            when 0
+              new_selector += selector
+              new_selector += parse_string(scanner, scanner[0])
+            when 1
+              new_selector += selector[0..-3]
+              new_selector += '"'
+            else
+              raise 'should only be 0 or 1 backslash at this location'
+            end
+
+          when '{'
+            # check if it is escaped
+            # should only be 0 or 1 backslash before { since we scan until will we find an escaped backslash or curly
+            backslashes = /\\*\z/
+                          .match(selector[0..-2])
+                          .yield_self { |match| match[0].length }
+
+            case backslashes
+            when 0
+              new_selector += selector[0..-2]
+            when 1
+              new_selector += selector[0..-3] # "remove last \ and {  and append { to selector"
+              new_selector += '{'
+            else
+              raise 'should only be 0 or 1 backslash at this location'
+            end
+
+            # If these is an odd number of backslashes it is expected
+            got_to_properties = backslashes.even?
+          else
+            raise "got something unexpected #{scanner.values_at(0).inspect}"
+          end
+        end
+
+        new_selector
+      end
+
+      def self.parse_proppertied(scanner)
+        properties = ''
+        end_of_propertied = false
+
+        until end_of_propertied
+          selector = scanner.scan_until(/'|"|}/)
+          case scanner[0]
+          when nil
+            raise 'CSS invalid stylesheet, could not find end of properties'
+          when '"', "'"
+            backslashes = /\\*\z/.match(selector[0..-2])[0].length
+            raise 'Dont think you can have any escaped quates here' unless backslashes == 0
+
+            properties += selector
+            properties += parse_string(scanner, scanner[0])
+          when '}'
+            properties += selector[0..-2]
+            end_of_propertied = true
+          else
+            raise "got something unexpected #{scanner.values_at(0).inspect}"
+          end
+        end
+
+        properties.strip
+      end
+    end
+  end
+end

test/rule_set/test_declarations.rb

@@ -159,7 +159,7 @@ class RuleSetDeclarationsTest < Minitest::Test
       declarations = CssParser::RuleSet::Declarations.new({foo: 'foo value'})
       assert_equal 1, declarations.size
 
-      declarations.remove_declaration!('fOo'.to_sym)
+      declarations.remove_declaration!(:fOo)
 
       assert_equal 0, declarations.size
     end

test/test_css_parser_basic.rb

@@ -34,9 +34,51 @@ def test_adding_block_without_closing_brace
     assert_equal 'color: red;', @cp.find_by_selector('p').join
   end
 
-  def test_adding_a_rule
-    @cp.add_rule!('div', 'color: blue;')
-    assert_equal 'color: blue;', @cp.find_by_selector('div').join(' ')
+  def test_add_multiple_selectors_in_one_go
+    @cp.add_block!('p, span { color: red; }')
+    assert_equal({"p" => {"color" => "red"}, "span" => {"color" => "red"}}, @cp.to_h["all"])
+  end
+
+  def test_selector_with_backslash
+    @cp.add_block!('.back\\slash { color: red; }')
+    assert_equal({".back\\slash" => {"color" => "red"}}, @cp.to_h["all"])
+  end
+
+  def test_selector_with_doublequoute
+    @cp.add_block!(<<-CSS)
+      .double\\"quote { color: red; }
+    CSS
+    assert_equal({'.double"quote' => {"color" => "red"}}, @cp.to_h["all"])
+  end
+
+  def test_selector_with_singlequoute
+    @cp.add_block!(<<-CSS)
+      .double\\"quote { color: red; }
+    CSS
+    pp @cp.to_h["all"]
+    assert_equal({".double'quote" => {"color" => "red"}}, @cp.to_h["all"])
+  end
+
+  def test_add_nested_selection
+    @cp.add_block!(<<-CSS)
+      p > span { color: red; }
+    CSS
+    assert_equal({"p > span" => {"color" => "red"}}, @cp.to_h["all"])
+  end
+
+  def test_selector_with_attrubute_selector
+    @cp.add_block!('input[type="checkbox"] { color: red; }')
+    assert_equal({"input[type=\"checkbox\"]" => {"color" => "red"}}, @cp.to_h["all"])
+  end
+
+  def test_not_modifier
+    @cp.add_block!('td:not(.active) { color: red;')
+    assert_equal({"td:not(.active)" => {"color" => "red"}}, @cp.to_h["all"])
+  end
+
+  def test_not_modifier_with_two_classes
+    @cp.add_block!('td:not(.active, .disabled) { color: red;')
+    assert_equal({"td:not(.active, .disabled)" => {"color" => "red"}}, @cp.to_h["all"])
   end
 
   def test_adding_a_rule_set
@@ -45,6 +87,11 @@ def test_adding_a_rule_set
     assert_equal 'color: blue;', @cp.find_by_selector('div').join(' ')
   end
 
+  def test_adding_a_rule
+    @cp.add_rule!('div', 'color: blue;')
+    assert_equal 'color: blue;', @cp.find_by_selector('div').join(' ')
+  end
+
   def test_removing_a_rule_set
     rs = CssParser::RuleSet.new('div', 'color: blue;')
     @cp.add_rule_set!(rs)