Added validation macros to make the stackable just like the lifecycle callbacks

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@94 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/CHANGELOG

@@ -1,5 +1,18 @@
 *CVS*
 
+* Added validation macros to make the stackable just like the lifecycle callbacks. Examples:
+
+    class Person < ActiveRecord::Base
+      validate { |record| record.errors.add("name", "too short") unless name.size > 10 }
+      validate { |record| record.errors.add("name", "too long")  unless name.size < 20 }
+      validate_on_create :validate_password
+      
+      private
+        def validate_password
+          errors.add("password", "too short") unless password.size > 6
+        end
+    end
+
 * Added ActiveRecord::Mixins::Touch that will record creation and update times of objects [xal]. Example:
 
     class Bill < ActiveRecord::Base

activerecord/lib/active_record/validations.rb

@@ -37,6 +37,8 @@ module ActiveRecord
   #
   # An +Errors+ object is automatically created for every Active Record.
   module Validations
+    VALIDATIONS = %w( validate validate_on_create validate_on_create )
+
     def self.append_features(base) # :nodoc:
       super
 
@@ -46,6 +48,8 @@ module ActiveRecord
 
         alias_method :update_attribute_without_validation_skipping, :update_attribute
         alias_method :update_attribute, :update_attribute_with_validation_skipping
+
+        VALIDATIONS.each { |vd| base.class_eval("def self.#{vd}(*methods) write_inheritable_array(\"#{vd}\", methods - (read_inheritable_attribute(\"#{vd}\") || [])) end") }
       end
     end
 
@@ -66,8 +70,18 @@ module ActiveRecord
     # Runs validate and validate_on_create or validate_on_update and returns true if no errors were added otherwise false.
     def valid?
       errors.clear
+
+      run_validations(:validate)
       validate
-      if new_record? then validate_on_create else validate_on_update end
+
+      if new_record?
+        run_validations(:validate_on_create)
+        validate_on_create 
+      else
+        run_validations(:validate_on_update)
+        validate_on_update
+      end
+
       errors.empty?
     end
 
@@ -89,6 +103,37 @@ module ActiveRecord
       # Overwrite this method for validation checks used only on updates.
       def validate_on_update # :doc:
       end
+
+    private
+      def run_validations(validation_method)
+        validations = self.class.read_inheritable_attribute(validation_method.to_s)
+        if validations.nil? then return end
+        validations.each do |validation|
+          if Symbol === validation
+            self.send(validation)
+          elsif String === validation
+            eval(validation, binding)
+          elsif validation_block?(validation)
+            validation.call(self)
+          elsif filter_class?(validation, validation_method)
+            validation.send(validation_method, self)
+          else
+            raise(
+              ActiveRecordError,
+              "Validations need to be either a symbol, string (to be eval'ed), proc/method, or " +
+              "class implementing a static validation method"
+            )
+          end
+        end
+      end
+
+      def validation_block?(validation)
+        validation.respond_to?("call") && (validation.arity == 1 || validation.arity == -1)
+      end
+
+      def validation_class?(validation, validation_method)
+        validation.respond_to?(validation_method)
+      end
   end
 
   # Active Record validation is reported to and from this object, which is used by Base#save to

activerecord/test/fixtures/reply.rb

@@ -1,20 +1,29 @@
 class Reply < Topic
   belongs_to :topic, :foreign_key => "parent_id", :counter_cache => true
 
+  validate :errors_on_empty_content
+  validate_on_create :title_is_wrong_create
+  
   attr_accessible :title, :author_name, :author_email_address, :written_on, :content, :last_read
 
   def validate
     errors.add("title", "Empty")   unless attribute_present? "title"
+  end
+  
+  def errors_on_empty_content
     errors.add("content", "Empty") unless attribute_present? "content"
   end
   
   def validate_on_create
-    errors.add("title", "is Wrong Create") if attribute_present?("title") && title == "Wrong Create"
     if attribute_present?("title") && attribute_present?("content") && content == "Mismatch"
       errors.add("title", "is Content Mismatch") 
     end
   end
 
+  def title_is_wrong_create
+    errors.add("title", "is Wrong Create") if attribute_present?("title") && title == "Wrong Create"
+  end
+
   def validate_on_update
     errors.add("title", "is Wrong Update") if attribute_present?("title") && title == "Wrong Update"
   end