+++ /dev/null
-module ActiveRecord
- # Track unsaved attribute changes.
- #
- # A newly instantiated object is unchanged:
- # person = Person.find_by_name('uncle bob')
- # person.changed? # => false
- #
- # Change the name:
- # person.name = 'Bob'
- # person.changed? # => true
- # person.name_changed? # => true
- # person.name_was # => 'uncle bob'
- # person.name_change # => ['uncle bob', 'Bob']
- # person.name = 'Bill'
- # person.name_change # => ['uncle bob', 'Bill']
- #
- # Save the changes:
- # person.save
- # person.changed? # => false
- # person.name_changed? # => false
- #
- # Assigning the same value leaves the attribute unchanged:
- # person.name = 'Bill'
- # person.name_changed? # => false
- # person.name_change # => nil
- #
- # Which attributes have changed?
- # person.name = 'bob'
- # person.changed # => ['name']
- # person.changes # => { 'name' => ['Bill', 'bob'] }
- #
- # Before modifying an attribute in-place:
- # person.name_will_change!
- # person.name << 'by'
- # person.name_change # => ['uncle bob', 'uncle bobby']
- module Dirty
- DIRTY_SUFFIXES = ['_changed?', '_change', '_will_change!', '_was']
-
- def self.included(base)
- base.attribute_method_suffix *DIRTY_SUFFIXES
- base.alias_method_chain :write_attribute, :dirty
- base.alias_method_chain :save, :dirty
- base.alias_method_chain :save!, :dirty
- base.alias_method_chain :update, :dirty
- base.alias_method_chain :reload, :dirty
-
- base.superclass_delegating_accessor :partial_updates
- base.partial_updates = true
-
- base.send(:extend, ClassMethods)
- end
-
- # Do any attributes have unsaved changes?
- # person.changed? # => false
- # person.name = 'bob'
- # person.changed? # => true
- def changed?
- !changed_attributes.empty?
- end
-
- # List of attributes with unsaved changes.
- # person.changed # => []
- # person.name = 'bob'
- # person.changed # => ['name']
- def changed
- changed_attributes.keys
- end
-
- # Map of changed attrs => [original value, new value].
- # person.changes # => {}
- # person.name = 'bob'
- # person.changes # => { 'name' => ['bill', 'bob'] }
- def changes
- changed.inject({}) { |h, attr| h[attr] = attribute_change(attr); h }
- end
-
- # Attempts to +save+ the record and clears changed attributes if successful.
- def save_with_dirty(*args) #:nodoc:
- if status = save_without_dirty(*args)
- changed_attributes.clear
- end
- status
- end
-
- # Attempts to <tt>save!</tt> the record and clears changed attributes if successful.
- def save_with_dirty!(*args) #:nodoc:
- status = save_without_dirty!(*args)
- changed_attributes.clear
- status
- end
-
- # <tt>reload</tt> the record and clears changed attributes.
- def reload_with_dirty(*args) #:nodoc:
- record = reload_without_dirty(*args)
- changed_attributes.clear
- record
- end
-
- private
- # Map of change <tt>attr => original value</tt>.
- def changed_attributes
- @changed_attributes ||= {}
- end
-
- # Handle <tt>*_changed?</tt> for +method_missing+.
- def attribute_changed?(attr)
- changed_attributes.include?(attr)
- end
-
- # Handle <tt>*_change</tt> for +method_missing+.
- def attribute_change(attr)
- [changed_attributes[attr], __send__(attr)] if attribute_changed?(attr)
- end
-
- # Handle <tt>*_was</tt> for +method_missing+.
- def attribute_was(attr)
- attribute_changed?(attr) ? changed_attributes[attr] : __send__(attr)
- end
-
- # Handle <tt>*_will_change!</tt> for +method_missing+.
- def attribute_will_change!(attr)
- changed_attributes[attr] = clone_attribute_value(:read_attribute, attr)
- end
-
- # Wrap write_attribute to remember original attribute value.
- def write_attribute_with_dirty(attr, value)
- attr = attr.to_s
-
- # The attribute already has an unsaved change.
- if changed_attributes.include?(attr)
- old = changed_attributes[attr]
- changed_attributes.delete(attr) unless field_changed?(attr, old, value)
- else
- old = clone_attribute_value(:read_attribute, attr)
- changed_attributes[attr] = old if field_changed?(attr, old, value)
- end
-
- # Carry on.
- write_attribute_without_dirty(attr, value)
- end
-
- def update_with_dirty
- if partial_updates?
- # Serialized attributes should always be written in case they've been
- # changed in place.
- update_without_dirty(changed | self.class.serialized_attributes.keys)
- else
- update_without_dirty
- end
- end
-
- def field_changed?(attr, old, value)
- if column = column_for_attribute(attr)
- if column.number? && column.null && (old.nil? || old == 0) && value.blank?
- # For nullable numeric columns, NULL gets stored in database for blank (i.e. '') values.
- # Hence we don't record it as a change if the value changes from nil to ''.
- # If an old value of 0 is set to '' we want this to get changed to nil as otherwise it'll
- # be typecast back to 0 (''.to_i => 0)
- value = nil
- else
- value = column.type_cast(value)
- end
- end
-
- old != value
- end
-
- module ClassMethods
- def self.extended(base)
- base.metaclass.alias_method_chain(:alias_attribute, :dirty)
- end
-
- def alias_attribute_with_dirty(new_name, old_name)
- alias_attribute_without_dirty(new_name, old_name)
- DIRTY_SUFFIXES.each do |suffix|
- module_eval <<-STR, __FILE__, __LINE__+1
- def #{new_name}#{suffix}; self.#{old_name}#{suffix}; end # def subject_changed?; self.title_changed?; end
- STR
- end
- end
- end
- end
-end
projects / feedcatcher.git / blobdiff