adding aliasing of actions

lib/cancan/ability.rb

@@ -4,30 +4,47 @@ module CanCan
       base.extend ClassMethods
     end
     
-    def can?(action, target)
-      self.class.can_history.reverse.each do |can_action, can_target, can_block|
-        if (can_action == :manage || can_action == action) && (can_target == :all || can_target == target || target.kind_of?(can_target))
-          if can_block.nil?
-            return true
-          else
-            block_args = []
-            block_args << action if can_action == :manage
-            block_args << (target.class == Class ? target : target.class) if can_target == :all
-            block_args << (target.class == Class ? nil : target)
-            return can_block.call(*block_args)
+    def can?(original_action, target)
+      (self.class.can_history || []).reverse.each do |can_action, can_target, can_block|
+        possible_actions_for(original_action).each do |action|
+          if (can_action == :manage || can_action == action) && (can_target == :all || can_target == target || target.kind_of?(can_target))
+            if can_block.nil?
+              return true
+            else
+              block_args = []
+              block_args << action if can_action == :manage
+              block_args << (target.class == Class ? target : target.class) if can_target == :all
+              block_args << (target.class == Class ? nil : target)
+              return can_block.call(*block_args)
+            end
           end
         end
       end
       false
     end
     
+    def possible_actions_for(initial_action)
+      actions = [initial_action]
+      (self.class.aliased_actions || []).each do |target, aliases|
+        actions += possible_actions_for(target) if aliases.include? initial_action
+      end
+      actions
+    end
+    
     module ClassMethods
       attr_reader :can_history
+      attr_reader :aliased_actions
       
       def can(action, target, &block)
         @can_history ||= []
         @can_history << [action, target, block]
       end
+      
+      def alias_action(*args)
+        @aliased_actions ||= {}
+        target = args.pop[:to]
+        @aliased_actions[target] = args
+      end
     end
   end
 end

spec/cancan/ability_spec.rb

@@ -2,6 +2,8 @@ require File.dirname(__FILE__) + '/../spec_helper'
 
 class Ability
   include CanCan::Ability
+  alias_action :update, :destroy, :to => :modify
+  
   can :read, :all
   can :read, Symbol do |sym|
     sym
@@ -12,6 +14,9 @@ class Ability
   can :manage, Array do |action, object|
     [action, object]
   end
+  can :modify, :all do |object_class, object|
+    :modify_called
+  end
 end
 
 class AdminAbility
@@ -52,6 +57,11 @@ describe Ability do
     @ability.can?(:stuff, [1, 2]).should == [:stuff, [1, 2]]
     @ability.can?(:stuff, Array).should == [:stuff, nil]
   end
+  
+  it "should alias update or destroy actions to modify action" do
+    @ability.can?(:update, 123).should == :modify_called
+    @ability.can?(:destroy, 123).should == :modify_called
+  end
 end
 
 describe AdminAbility do