Add support for Mongoid::Criteria Symbol extensions (:age.gt => 10) along with specs.

cancan.gemspec

@@ -18,6 +18,8 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'mongoid', '~> 2.0.0.beta.19'
   s.add_development_dependency 'bson_ext', '~> 1.1'
   
+  s.add_development_dependency 'ruby-debug'
+  
   s.rubyforge_project = s.name
   s.required_rubygems_version = ">= 1.3.4"
 end

lib/cancan/mongoid_additions.rb

@@ -26,6 +26,42 @@ module CanCan
     end
   end
 
+  # customize to handle Mongoid queries in ability definitions conditions
+  class CanDefinition
+    def matches_conditions_hash?(subject, conditions = @conditions)          
+      if subject.class.include?(Mongoid::Document)        # Mongoid Criteria are simpler to check than normal conditions hashes
+        if conditions.empty?  # When no conditions are given, true should be returned.
+                              # The default CanCan behavior relies on the fact that conditions.all? will return true when conditions is empty
+                              # The way ruby handles all? for empty hashes can be unexpected:
+                              #   {}.all?{|a| a == 5} 
+                              #   => true
+                              #   {}.all?{|a| a != 5} 
+                              #   => true
+          true
+        else
+          subject.class.where(conditions).include?(subject)  # just use Mongoid's where function
+        end
+      else 
+        conditions.all? do |name, value|
+          attribute = subject.send(name)
+          if value.kind_of?(Hash)
+            if attribute.kind_of? Array
+              attribute.any? { |element| matches_conditions_hash? element, value }
+            else
+              matches_conditions_hash? attribute, value
+            end
+          elsif value.kind_of?(Array) || value.kind_of?(Range)
+            value.include? attribute
+          else
+            attribute == value
+          end
+        end
+      end
+    end
+  end
+
+
+
   module MongoidAdditions
     module ClassMethods
       # Returns a scope which fetches only the records that the passed ability

spec/cancan/mongoid_additions_spec.rb

@@ -3,11 +3,14 @@ require 'mongoid'
 
 class MongoidCategory
   include Mongoid::Document
+  include CanCan::MongoidAdditions
+
   references_many :mongoid_projects
 end
 
 class MongoidProject
   include Mongoid::Document
+  include CanCan::MongoidAdditions
   
   referenced_in :mongoid_category
 
@@ -36,9 +39,7 @@ end
 
 describe CanCan::MongoidAdditions do
   before(:each) do
-    @model_class = Class.new(MongoidProject)
-    stub(@model_class).scoped { :scoped_stub }
-    @model_class.send(:include, CanCan::MongoidAdditions)
+    @model_class = MongoidProject
     @ability = Object.new
     @ability.extend(CanCan::Ability)
   end
@@ -52,6 +53,53 @@ describe CanCan::MongoidAdditions do
   it "should return [] when no ability is defined so no records are found" do
     @model_class.accessible_by(@ability, :read).should == []
   end
+  
+  describe "Mongoid::Criteria where clause Symbol extensions using MongoDB expressions" do
+    it "should handle :field.in" do
+      obj = @model_class.create :title  => 'Sir'
+      @ability.can :read, @model_class, :title.in => ["Sir", "Madam"]
+      @ability.can?(:read, obj).should == true
+      
+      obj2 = @model_class.create :title  => 'Lord'
+      @ability.can?(:read, obj2).should == false
+    end
+    
+    it "should handle :field.nin" do
+      obj = @model_class.create :title  => 'Sir'
+      @ability.can :read, @model_class, :title.nin => ["Lord", "Madam"]
+      @ability.can?(:read, obj).should == true
+      
+      obj2 = @model_class.create :title  => 'Lord'
+      @ability.can?(:read, obj2).should == false
+    end
+    
+    it "should handle :field.size" do
+      obj = @model_class.create :titles  => ['Palatin', 'Margrave']
+      @ability.can :read, @model_class, :titles.size => 2
+      @ability.can?(:read, obj).should == true
+      
+      obj2 = @model_class.create :titles  => ['Palatin', 'Margrave', 'Marquis']
+      @ability.can?(:read, obj2).should == false
+    end    
+
+    it "should handle :field.exists" do
+      obj = @model_class.create :titles  => ['Palatin', 'Margrave']
+      @ability.can :read, @model_class, :titles.exists => true
+      @ability.can?(:read, obj).should == true
+      
+      obj2 = @model_class.create
+      @ability.can?(:read, obj2).should == false
+    end
+    
+    it "should handle :field.gt" do
+      obj = @model_class.create :age  => 50
+      @ability.can :read, @model_class, :age.gt => 45
+      @ability.can?(:read, obj).should == true
+      
+      obj2 = @model_class.create :age  => 40
+      @ability.can?(:read, obj2).should == false
+    end    
+  end
 
   it "should call where with matching ability conditions" do
     @ability.can :read, @model_class, :foo => {:bar => 1}