1 files changed, 123 insertions, 0 deletions
diff --git a/guides/rails_guides/markdown/renderer.rb b/guides/rails_guides/markdown/renderer.rb
new file mode 100644
index 0000000000..78820a7856
--- /dev/null
+++ b/guides/rails_guides/markdown/renderer.rb
@@ -0,0 +1,123 @@
+# frozen_string_literal: true
+
+module RailsGuides
+  class Markdown
+    class Renderer < Redcarpet::Render::HTML
+      cattr_accessor :edge, :version
+
+      def block_code(code, language)
+        <<-HTML
+<div class="code_container">
+<pre class="brush: #{brush_for(language)}; gutter: false; toolbar: false">
+#{ERB::Util.h(code)}
+</pre>
+</div>
+HTML
+      end
+
+      def link(url, title, content)
+        if url.start_with?("http://api.rubyonrails.org")
+          %(<a href="#{api_link(url)}">#{content}</a>)
+        elsif title
+          %(<a href="#{url}" title="#{title}">#{content}</a>)
+        else
+          %(<a href="#{url}">#{content}</a>)
+        end
+      end
+
+      def header(text, header_level)
+        # Always increase the heading level by 1, so we can use h1, h2 heading in the document
+        header_level += 1
+
+        %(<h#{header_level}>#{text}</h#{header_level}>)
+      end
+
+      def paragraph(text)
+        if text =~ %r{^NOTE:\s+Defined\s+in\s+<code>(.*?)</code>\.?$}
+          %(<div class="note"><p>Defined in <code><a href="#{github_file_url($1)}">#{$1}</a></code>.</p></div>)
+        elsif text =~ /^(TIP|IMPORTANT|CAUTION|WARNING|NOTE|INFO|TODO)[.:]/
+          convert_notes(text)
+        elsif text.include?("DO NOT READ THIS FILE ON GITHUB")
+        elsif text =~ /^\[<sup>(\d+)\]:<\/sup> (.+)$/
+          linkback = %(<a href="#footnote-#{$1}-ref"><sup>#{$1}</sup></a>)
+          %(<p class="footnote" id="footnote-#{$1}">#{linkback} #{$2}</p>)
+        else
+          text = convert_footnotes(text)
+          "<p>#{text}</p>"
+        end
+      end
+
+      private
+
+        def convert_footnotes(text)
+          text.gsub(/\[<sup>(\d+)\]<\/sup>/i) do
+            %(<sup class="footnote" id="footnote-#{$1}-ref">) +
+              %(<a href="#footnote-#{$1}">#{$1}</a></sup>)
+          end
+        end
+
+        def brush_for(code_type)
+          case code_type
+          when "ruby", "sql", "plain"
+            code_type
+          when "erb", "html+erb"
+            "ruby; html-script: true"
+          when "html"
+            "xml" # HTML is understood, but there are .xml rules in the CSS
+          else
+            "plain"
+          end
+        end
+
+        def convert_notes(body)
+          # The following regexp detects special labels followed by a
+          # paragraph, perhaps at the end of the document.
+          #
+          # It is important that we do not eat more than one newline
+          # because formatting may be wrong otherwise. For example,
+          # if a bulleted list follows, the first item is not rendered
+          # as a list item, but as a paragraph starting with a plain
+          # asterisk.
+          body.gsub(/^(TIP|IMPORTANT|CAUTION|WARNING|NOTE|INFO|TODO)[.:](.*?)(\n(?=\n)|\Z)/m) do
+            css_class = \
+              case $1
+              when "CAUTION", "IMPORTANT"
+                "warning"
+              when "TIP"
+                "info"
+              else
+                $1.downcase
+              end
+            %(<div class="#{css_class}"><p>#{$2.strip}</p></div>)
+          end
+        end
+
+        def github_file_url(file_path)
+          tree = version || edge
+
+          root = file_path[%r{(\w+)/}, 1]
+          path = \
+            case root
+            when "abstract_controller", "action_controller", "action_dispatch"
+              "actionpack/lib/#{file_path}"
+            when /\A(action|active)_/
+              "#{root.sub("_", "")}/lib/#{file_path}"
+            else
+              file_path
+            end
+
+          "https://github.com/rails/rails/tree/#{tree}/#{path}"
+        end
+
+        def api_link(url)
+          if url =~ %r{http://api\.rubyonrails\.org/v\d+\.}
+            url
+          elsif edge
+            url.sub("api", "edgeapi")
+          else
+            url.sub(/(?<=\.org)/, "/#{version}")
+          end
+        end
+    end
+  end
+end