Referring Pages for File List

For the file_list  action, include the pages which link to the given file(s).
This required rejiggering so that that information is actually retained in the database.
Unfortunately, you'll actually need to revise the page(s) in question, because that's the
only time this information is updated in the database.

app/models/web.rb

@@ -51,6 +51,10 @@ class Web < ActiveRecord::Base
     WikiFile.all(:order => sort_order, :conditions => ['web_id = ?', id])
   end
 
+  def pages_that_link_to(file_name)
+    WikiReference.pages_that_link_to_file(self, file_name)
+  end
+  
   def description(file_name)
     file = WikiFile.find_by_file_name(file_name)
     file.description if file

app/models/wiki_reference.rb

@@ -33,6 +33,15 @@ class WikiReference < ActiveRecord::Base
     names = connection.select_all(sanitize_sql([query, page_name])).map { |row| row['name'] }
   end
   
+  def self.pages_that_link_to_file(web, file_name)
+    query = 'SELECT name FROM pages JOIN wiki_references ' +
+      'ON pages.id = wiki_references.page_id ' +
+      'WHERE wiki_references.referenced_name = ? ' +
+      "AND wiki_references.link_type in ('#{FILE}') " +
+      "AND pages.web_id = '#{web.id}'"
+    names = connection.select_all(sanitize_sql([query, file_name])).map { |row| row['name'] }
+  end
+  
   def self.pages_that_include(web, page_name)
     query = 'SELECT name FROM pages JOIN wiki_references ' +
       'ON pages.id = wiki_references.page_id ' +

app/views/wiki/file_list.html.erb

@@ -18,7 +18,10 @@
     <li>
       <input type="checkbox" name="<%= file.file_name %>" value="delete"/>
       <a href="<%= url_for :web => @web.address, :action => 'files', 
-            :id => file.file_name %>"><%= file.file_name%></a> (<%= file.created_at.asctime %>)
+            :id => file.file_name %>"><%= file.file_name%></a> (<%= file.created_at.asctime %>) <span class="linked"><%= 
+            "Linked to by: " unless @web.pages_that_link_to(file.file_name).empty? 
+             @web.pages_that_link_to(file.file_name).collect { |referring_page| 
+                link_to  referring_page }.join(", ") %></span>
     </li>
   <%- end -%>
   </ul>

lib/page_renderer.rb

@@ -97,14 +97,29 @@ class PageRenderer
   def wiki_words
     @wiki_words_cache ||= find_wiki_words(display_content) 
   end
-
+  
   def find_wiki_words(rendering_result)
-    wiki_links = rendering_result.find_chunks(WikiChunk::WikiLink)
+    the_wiki_words = wiki_links(rendering_result)
     # Exclude backslash-escaped wiki words, such as \WikiWord, as well as links to files 
     # and pictures, such as [[foo.txt:file]] or [[foo.jpg:pic]]
-    wiki_links.delete_if { |link| link.escaped? or [:pic, :file].include?(link.link_type) }
+    the_wiki_words.delete_if { |link| link.escaped? or [:pic, :file, :delete].include?(link.link_type) }
     # convert to the list of unique page names
-    wiki_links.map { |link| ( link.page_name ) }.uniq
+    the_wiki_words.map { |link| ( link.page_name ) }.uniq
+  end
+
+  # Returns an array of all the WikiWords present in the content of this revision.
+  def wiki_files
+    @wiki_files_cache ||= find_wiki_files(display_content) 
+  end
+    
+  def find_wiki_files(rendering_result)
+     the_wiki_files = wiki_links(rendering_result)
+     the_wiki_files.delete_if { |link| ![:pic, :file].include?(link.link_type) }
+     the_wiki_files.map { |link| ( link.page_name ) }.uniq
+  end
+  
+  def wiki_links(rendering_result)
+     rendering_result.find_chunks(WikiChunk::WikiLink)
   end
 
   # Returns an array of all the WikiWords present in the content of this revision.
@@ -146,6 +161,11 @@ class PageRenderer
       references.build :referenced_name => referenced_name, :link_type => link_type
     end
     
+    wiki_files = find_wiki_files(rendering_result)
+    wiki_files.each do |referenced_name|
+      references.build :referenced_name => referenced_name, :link_type => WikiReference::FILE
+    end
+    
     include_chunks = rendering_result.find_chunks(Include)
     includes = include_chunks.map { |c| ( c.escaped? ? nil : c.page_name ) }.compact.uniq
     includes.each do |included_page_name|