Extacted rendering logic from the model

lib/page_renderer.rb

@@ -0,0 +1,106 @@
+# Temporary class containing all rendering stuff from a Revision 
+# I want to shift all rendering loguc to the controller eventually
+
+class PageRenderer
+
+  def initialize(revision)
+    @revision = revision
+  end
+
+  # Returns an array of all the WikiIncludes present in the content of this revision.
+  def wiki_includes
+    unless @wiki_includes_cache 
+      chunks = display_content.find_chunks(Include)
+      @wiki_includes_cache = chunks.map { |c| ( c.escaped? ? nil : c.page_name ) }.compact.uniq
+    end
+    @wiki_includes_cache
+  end
+
+  # Returns an array of all the WikiReferences present in the content of this revision.
+  def wiki_references
+    unless @wiki_references_cache 
+      chunks = display_content.find_chunks(WikiChunk::WikiReference)
+      @wiki_references_cache = chunks.map { |c| ( c.escaped? ? nil : c.page_name ) }.compact.uniq
+    end
+    @wiki_references_cache
+  end  
+
+  # Returns an array of all the WikiWords present in the content of this revision.
+  def wiki_words
+    unless @wiki_words_cache
+      wiki_chunks = display_content.find_chunks(WikiChunk::WikiLink)
+      @wiki_words_cache = wiki_chunks.map { |c| ( c.escaped? ? nil : c.page_name ) }.compact.uniq
+    end
+    @wiki_words_cache
+  end
+
+  # Returns an array of all the WikiWords present in the content of this revision.
+  # that already exists as a page in the web.
+  def existing_pages
+    wiki_words.select { |wiki_word| @revision.page.web.page(wiki_word) }
+  end
+
+  # Returns an array of all the WikiWords present in the content of this revision
+  # that *doesn't* already exists as a page in the web.
+  def unexisting_pages
+    wiki_words - existing_pages
+  end  
+
+  # Explicit check for new type of display cache with chunks_by_type method.
+  # Ensures new version works with older snapshots.
+  def display_content
+    unless @display_cache && @display_cache.respond_to?(:chunks_by_type)
+      @display_cache = WikiContent.new(@revision)
+      @display_cache.render!
+    end
+    @display_cache
+  end
+
+  # TODO this probably doesn't belong in revision (because it has to call back the page)
+  def display_diff
+    previous_revision = @revision.page.previous_revision(@revision)
+    if previous_revision 
+      HTMLDiff.diff(PageRenderer.new(previous_revision).display_content, display_content) 
+    else 
+      display_content
+    end
+  end
+
+  def clear_display_cache
+    @wiki_words_cache = @published_cache = @display_cache = @wiki_includes_cache = 
+      @wiki_references_cache = nil
+  end
+
+  def display_published
+    unless @published_cache && @published_cache.respond_to?(:chunks_by_type)
+      @published_cache = WikiContent.new(@revision, {:mode => :publish})
+      @published_cache.render!
+    end
+    @published_cache
+  end
+
+  def display_content_for_export
+    WikiContent.new(@revision, {:mode => :export} ).render!
+  end
+  
+  def force_rendering
+    begin
+      display_content.render!
+    rescue => e
+      logger.error "Failed rendering page #{@name}"
+      logger.error e
+      message = e.message
+      # substitute content with an error message
+      @revision.content = <<-EOL
+          <p>Markup engine has failed to render this page, raising the following error:</p>
+          <p>#{message}</p>
+          <pre>#{self.content}</pre>
+      EOL
+      clear_display_cache
+      raise e
+    end
+  end
+
+  protected
+
+end