# File lib/acts_as_versioned.rb, line 243
243:         def changed?(attr_name = nil)
244:           attr_name.nil? ?
245:             (!self.class.track_changed_attributes or (changed_attributes and changed_attributes.length > 0)) :
246:             (changed_attributes and changed_attributes.include?(attr_name.to_s))
247:         end

     # File lib/acts_as_versioned.rb, line 186
186:         def clear_old_versions
187:           return if self.class.max_version_limit.blank?
188:           excess_baggage = send(self.class.version_column).to_i - self.class.max_version_limit
189:           if excess_baggage > 0
190:             sql = "DELETE FROM #{self.class.versioned_table_name} WHERE version <= #{excess_baggage} AND #{self.class.versioned_foreign_key} = #{self.id}"
191:             self.class.versioned_class.connection.execute sql
192:           end
193:         end

     # File lib/acts_as_versioned.rb, line 253
253:         def clone_versioned_model(orig_model, new_model)
254:           self.versioned_attributes.each do |key|
255:             new_model.send("#{key}=", orig_model.attributes[key]) if orig_model.attribute_present?(key)
256:           end
257:           
258:           if orig_model.is_a?(self.class.versioned_class)
259:             new_model[new_model.class.inheritance_column] = orig_model[self.class.versioned_inheritance_column]
260:           elsif new_model.is_a?(self.class.versioned_class)
261:             new_model[self.class.versioned_inheritance_column] = orig_model[orig_model.class.inheritance_column]
262:           end
263:         end

     # File lib/acts_as_versioned.rb, line 196
196:         def find_version(version)
197:           return version if version.is_a?(self.class.versioned_class)
198:           return nil if version.is_a?(ActiveRecord::Base)
199:           find_versions(:conditions => ['version = ?', version], :limit => 1).first
200:         end

     # File lib/acts_as_versioned.rb, line 203
203:         def find_versions(options = {})
204:           versions.find(:all, options)
205:         end

     # File lib/acts_as_versioned.rb, line 208
208:         def revert_to(version)
209:           if version.is_a?(self.class.versioned_class)
210:             return false unless version.send(self.class.versioned_foreign_key) == self.id and !version.new_record?
211:           else
212:             return false unless version = find_version(version)
213:           end
214:           self.clone_versioned_model(version, self)
215:           self.send("#{self.class.version_column}=", version.version)
216:           true
217:         end

     # File lib/acts_as_versioned.rb, line 221
221:         def revert_to!(version)
222:           revert_to(version) ? save_without_revision : false
223:         end

     # File lib/acts_as_versioned.rb, line 171
171:         def save_version
172:           save_version_on_create if save_version?
173:         end

     # File lib/acts_as_versioned.rb, line 266
266:         def save_version?
267:           version_condition_met? and changed?
268:         end

     # File lib/acts_as_versioned.rb, line 176
176:         def save_version_on_create
177:           rev = self.class.versioned_class.new
178:           self.clone_versioned_model(self, rev)
179:           rev.version = send(self.class.version_column)
180:           rev.send("#{self.class.versioned_foreign_key}=", self.id)
181:           rev.save
182:         end

     # File lib/acts_as_versioned.rb, line 226
226:         def save_without_revision
227:           old_lock_value = ActiveRecord::Base.lock_optimistically
228:           ActiveRecord::Base.lock_optimistically = false if old_lock_value
229:           disable_acts_as_versioned_callbacks
230:           save_result = self.save
231:           enable_acts_as_versioned_callbacks
232:           ActiveRecord::Base.lock_optimistically = true if old_lock_value
233:           save_result
234:         end

     # File lib/acts_as_versioned.rb, line 272
272:         def version_condition_met?
273:           case
274:           when version_condition.is_a?(Symbol)
275:             send(version_condition)
276:           when version_condition.respond_to?(:call) && (version_condition.arity == 1 || version_condition.arity == -1)
277:             version_condition.call(self)
278:           else
279:             version_condition
280:           end          
281:         end

     # File lib/acts_as_versioned.rb, line 237
237:         def versioned_attributes
238:           self.attributes.keys.select { |k| !self.class.non_versioned_fields.include?(k) }
239:         end