Added a counter cache for the number of reshares of a post.

app/models/post.rb

@@ -53,10 +53,6 @@ class Post < ActiveRecord::Base
     new_post
   end
 
-  def reshare_count
-    @reshare_count ||= Post.find_all_by_root_guid(self.guid).count
-  end
-
   # @return Returns true if this Post will accept updates (i.e. updates to the caption of a photo).
   def mutable?
     false

app/models/reshare.rb

@@ -17,6 +17,14 @@ class Reshare < Post
     self.public = true
   end
 
+  after_create do
+    self.root.update_reshares_counter
+  end
+
+  after_destroy do
+    self.root.update_reshares_counter
+  end
+
   def root_diaspora_id
     self.root.author.diaspora_handle
   end
@@ -46,7 +54,7 @@ class Reshare < Post
     return if Post.exists?(:guid => self.root_guid)
 
     fetched_post = self.class.fetch_post(root_author, self.root_guid)
-    
+
     if fetched_post
       #Why are we checking for this?
       if root_author.diaspora_handle != fetched_post.diaspora_handle

app/views/reshares/_reshare.haml

@@ -16,7 +16,7 @@
             %span.timeago
               = link_to(how_long_ago(post), post_path(post))
             –
-            = t("reshares.reshare.reshare", :count => post.reshare_count)
+            = t("reshares.reshare.reshare", :count => post.reshares_count)
 
       - if post.activity_streams?
         = link_to image_tag(post.image_url, 'data-small-photo' => post.image_url, 'data-full-photo' => post.image_url, :class => 'stream-photo'), post.object_url, :class => "stream-photo-link"

app/views/shared/_stream_element.html.haml

@@ -32,7 +32,7 @@
           –
           %span.timeago
             = link_to(how_long_ago(post), post_path(post))
-          - if post.reshare_count > 0
+          - if post.reshares_count > 0
             –
             %span.num_reshares
               = t("reshares.reshare.reshare", :count => post.reshares.size)

db/migrate/20111111025358_counter_cache_on_post_reshares.rb

@@ -0,0 +1,22 @@
+class CounterCacheOnPostReshares < ActiveRecord::Migration
+  class Post < ActiveRecord::Base; end
+
+  def self.up
+    add_column :posts, :reshares_count, :integer, :default => 0
+
+    execute %{
+      UPDATE posts
+      SET reshares_count = (
+        SELECT COUNT(*)
+        FROM posts p2
+        WHERE
+          p2.type = 'Reshare'
+          AND p2.root_guid = posts.guid
+      )
+    }
+  end
+
+  def self.down
+    remove_column :posts, :reshares_count
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20111101202137) do
+ActiveRecord::Schema.define(:version => 20111111025358) do
 
   create_table "aspect_memberships", :force => true do |t|
     t.integer  "aspect_id",  :null => false
@@ -307,6 +307,7 @@ ActiveRecord::Schema.define(:version => 20111101202137) do
     t.integer  "likes_count",                         :default => 0
     t.integer  "comments_count",                      :default => 0
     t.integer  "o_embed_cache_id"
+    t.integer  "reshares_count",                      :default => 0
   end
 
   add_index "posts", ["author_id", "root_guid"], :name => "index_posts_on_author_id_and_root_guid", :unique => true

lib/diaspora/shareable.rb

@@ -107,6 +107,11 @@ module Diaspora
       end
     end
 
+    # @return [Integer]
+    def update_reshares_counter
+      self.class.where(:id => self.id).
+        update_all(:reshares_count => self.reshares.count)
+    end
 
     protected
 

spec/helpers/reshares_helper_spec.rb

@@ -22,7 +22,7 @@ describe ResharesHelper do
 
       describe 'which has not been reshared' do
         before :each do
-          @post.reshare_count.should == 0
+          @post.reshares_count.should == 0
         end
 
         it 'has "Reshare" as the English text' do
@@ -33,7 +33,8 @@ describe ResharesHelper do
       describe 'which has been reshared' do
         before :each do
           @reshare = Factory.create(:reshare, :root => @post)
-          @post.reshare_count.should == 1
+          @post.reload
+          @post.reshares_count.should == 1
         end
 
         it 'has "Reshare" as the English text' do

spec/models/post_spec.rb

@@ -379,7 +379,7 @@ describe Post do
     end
   end
 
-  describe '#reshare_count' do
+  describe '#reshares_count' do
     before :each do
       @post = @user.post :status_message, :text => "hello", :to => @aspect.id, :public => true
       @post.reshares.size.should == 0
@@ -387,7 +387,7 @@ describe Post do
 
     describe 'when post has not been reshared' do
       it 'returns zero' do
-        @post.reshare_count.should == 0
+        @post.reshares_count.should == 0
       end
     end
 
@@ -400,7 +400,7 @@ describe Post do
       end
 
       it 'returns 1' do
-        @post.reshare_count.should == 1
+        @post.reshares_count.should == 1
       end
     end
 
@@ -415,7 +415,7 @@ describe Post do
       end
 
       it 'returns the number of reshares' do
-        @post.reshare_count.should == 3
+        @post.reshares_count.should == 3
       end
     end
   end