From 82e7aa52c73072ffd3098f84ba734365b2add764 Mon Sep 17 00:00:00 2001
From: Jacques Distler <distler@golem.ph.utexas.edu>
Date: Sat, 10 Jan 2009 00:18:25 -0600
Subject: [PATCH] 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                 |  4 ++++
 app/models/wiki_reference.rb      |  9 +++++++++
 app/views/wiki/file_list.html.erb |  5 ++++-
 lib/page_renderer.rb              | 28 ++++++++++++++++++++++++----
 4 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/app/models/web.rb b/app/models/web.rb
index 2283407c..8adc0d70 100644
--- a/app/models/web.rb
+++ b/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
diff --git a/app/models/wiki_reference.rb b/app/models/wiki_reference.rb
index 9bcb7557..b00f37cd 100644
--- a/app/models/wiki_reference.rb
+++ b/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 ' +
diff --git a/app/views/wiki/file_list.html.erb b/app/views/wiki/file_list.html.erb
index cc649404..2b6f00e7 100644
--- a/app/views/wiki/file_list.html.erb
+++ b/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>
diff --git a/lib/page_renderer.rb b/lib/page_renderer.rb
index 9ad4609a..208dfa7d 100644
--- a/lib/page_renderer.rb
+++ b/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|