Jb/638 cache descendants

vendor/engines/your_platform/app/models/dag_link.rb

@@ -6,6 +6,7 @@ class DagLink < ActiveRecord::Base
 
   after_create :delete_cache
   after_save :delete_cache
+  after_destroy :delete_cache
 
   def delete_cache
     ancestor.delete_cache if ancestor.try(:respond_to?, :delete_cache)

vendor/engines/your_platform/app/models/group.rb

@@ -41,6 +41,7 @@ class Group < ActiveRecord::Base
   after_create     :import_default_group_structure  # from GroupMixins::Import
 
   def delete_cache
+    Structureable
     delete_cache_structureable
     delete_cached_leaf_groups
   end

vendor/engines/your_platform/app/models/page.rb

@@ -10,6 +10,7 @@ class Page < ActiveRecord::Base
   belongs_to :author, :class_name => "User", foreign_key: 'author_user_id'
 
   def delete_cache
+    Structureable
     delete_cache_structureable
   end
 
@@ -39,7 +40,7 @@ def to_param
   #
   def <<(child)
     unless child.in? self.children
-      if child.in? self.descendants
+      if child.in? self.cached_descendants
         link = DagLink.where(
           ancestor_type: 'Page', ancestor_id: self.id, 
           descendant_type: child.class.name, descendant_id: child.id

vendor/engines/your_platform/app/models/structureable.rb

@@ -121,7 +121,20 @@ def destroy_links
     end
 
     def delete_cache_structureable
+      delete_cached_descendants
       delete_cache_roles
     end
+
+    def delete_cached_descendants
+      Rails.cache.delete([self, 'descendants'])
+    end
+
+    def cached_descendants
+      Rails.cache.fetch([self, 'descendants'], expires_in: 1.week) do
+        descendant_pages(true) if self.respond_to?(:descendant_pages) 
+        descendant_groups(true) if self.respond_to?(:descendant_groups)
+        descendants
+      end
+    end
   end
 end

vendor/engines/your_platform/app/models/user.rb

@@ -719,7 +719,7 @@ def administrated_objects( role = :admin )
     objects = directly_administrated_objects( role )
     if objects
       objects += objects.collect do |directly_administrated_object|
-        directly_administrated_object.descendants
+        directly_administrated_object.cached_descendants
       end.flatten
       objects
     else

vendor/engines/your_platform/app/presenters/horizontal_nav_presenter.rb

@@ -63,7 +63,7 @@ def navable_is_most_special_category?( navable )
 
   def most_special_category
     categories_the_current_navable_falls_in.try(:select) do |navable|
-      (navable.descendants & categories_the_current_navable_falls_in).empty?
+      (navable.cached_descendants & categories_the_current_navable_falls_in).empty?
     end.try(:first)
   end  
 

vendor/engines/your_platform/spec/models/structureable_spec.rb

@@ -9,26 +9,86 @@
 
 describe Structureable do
 
-  describe ".is_structureable" do
+  describe '.is_structureable' do
 
-    before { @node = create( :page ) }
+    before { @node = create(:page) }
     subject { @node }
 
-    it "should provide the has_dag_links functionality" do
-      subject.should respond_to( :parents, :children, :ancestors, :descendants )
+    it 'should provide the has_dag_links functionality' do
+      subject.should respond_to(:parents, :children, :ancestors, :descendants)
     end
 
-    it "should provide the has_many_flags functionality" do
-      subject.should respond_to( :flags, :add_flag, :remove_flag )
+    it 'should provide the has_many_flags functionality' do
+      subject.should respond_to(:flags, :add_flag, :remove_flag)
     end
 
-    it "should make sure that when objects are destroyed, also their dag links are destroyed" do
-      @parent = create( :page )
+    it 'should make sure that when objects are destroyed, also their dag links are destroyed' do
+      @parent = create(:page)
       @parent.child_pages << @node
       @node.destroy
       @parent.links_as_parent.count.should == 0
     end
+  end
 
+  describe '#descendants' do
+    before do
+      @node = create(:page)
+    end
+    subject { @node.descendants }
+    it { should == [] }
+    describe "after adding child" do
+      before do
+        @child = create(:page)
+        @node.child_pages << @child
+      end
+      it { should include @child }
+    end
+    describe "after adding grandchildren" do
+      before do
+        @child = create(:page)
+        @grandchild = create(:page)
+        @node.child_pages << @child
+        @child.child_pages << @grandchild
+      end
+      it { should include @grandchild }
+    end
   end
 
+    describe '#cached_descendants' do
+    before do
+      @node = create(:page)
+    end
+    subject { @node.cached_descendants }
+    it { should == [] }
+    describe "after adding child" do
+      before do
+        @node.cached_descendants
+        @child = create(:page)
+        @node.child_pages << @child
+      end
+      it { should include @child }
+    end
+    describe "after adding grandchildren" do
+      before do
+        @node.cached_descendants
+        @child = create(:page)
+        @grandchild = create(:page)
+        @node.child_pages << @child
+        @child.child_pages << @grandchild
+      end
+      it { should include @grandchild }
+    end
+    describe "after removing grandchildren" do
+      before do
+        @child = create(:page)
+        @grandchild = create(:page)
+        @node.child_pages << @child
+        @child.child_pages << @grandchild
+        @node.cached_descendants
+        @grandchild.destroy_dag_links
+      end
+      it { should_not include @grandchild }
+    end
+  end
 end
+