--- /dev/null
+module ActiveRecord
+ module AttributeMethods #:nodoc:
+ DEFAULT_SUFFIXES = %w(= ? _before_type_cast)
+ ATTRIBUTE_TYPES_CACHED_BY_DEFAULT = [:datetime, :timestamp, :time, :date]
+
+ def self.included(base)
+ base.extend ClassMethods
+ base.attribute_method_suffix(*DEFAULT_SUFFIXES)
+ base.cattr_accessor :attribute_types_cached_by_default, :instance_writer => false
+ base.attribute_types_cached_by_default = ATTRIBUTE_TYPES_CACHED_BY_DEFAULT
+ base.cattr_accessor :time_zone_aware_attributes, :instance_writer => false
+ base.time_zone_aware_attributes = false
+ base.class_inheritable_accessor :skip_time_zone_conversion_for_attributes, :instance_writer => false
+ base.skip_time_zone_conversion_for_attributes = []
+ end
+
+ # Declare and check for suffixed attribute methods.
+ module ClassMethods
+ # Declares a method available for all attributes with the given suffix.
+ # Uses +method_missing+ and <tt>respond_to?</tt> to rewrite the method
+ #
+ # #{attr}#{suffix}(*args, &block)
+ #
+ # to
+ #
+ # attribute#{suffix}(#{attr}, *args, &block)
+ #
+ # An <tt>attribute#{suffix}</tt> instance method must exist and accept at least
+ # the +attr+ argument.
+ #
+ # For example:
+ #
+ # class Person < ActiveRecord::Base
+ # attribute_method_suffix '_changed?'
+ #
+ # private
+ # def attribute_changed?(attr)
+ # ...
+ # end
+ # end
+ #
+ # person = Person.find(1)
+ # person.name_changed? # => false
+ # person.name = 'Hubert'
+ # person.name_changed? # => true
+ def attribute_method_suffix(*suffixes)
+ attribute_method_suffixes.concat suffixes
+ rebuild_attribute_method_regexp
+ end
+
+ # Returns MatchData if method_name is an attribute method.
+ def match_attribute_method?(method_name)
+ rebuild_attribute_method_regexp unless defined?(@@attribute_method_regexp) && @@attribute_method_regexp
+ @@attribute_method_regexp.match(method_name)
+ end
+
+
+ # Contains the names of the generated attribute methods.
+ def generated_methods #:nodoc:
+ @generated_methods ||= Set.new
+ end
+
+ def generated_methods?
+ !generated_methods.empty?
+ end
+
+ # Generates all the attribute related methods for columns in the database
+ # accessors, mutators and query methods.
+ def define_attribute_methods
+ return if generated_methods?
+ columns_hash.each do |name, column|
+ unless instance_method_already_implemented?(name)
+ if self.serialized_attributes[name]
+ define_read_method_for_serialized_attribute(name)
+ elsif create_time_zone_conversion_attribute?(name, column)
+ define_read_method_for_time_zone_conversion(name)
+ else
+ define_read_method(name.to_sym, name, column)
+ end
+ end
+
+ unless instance_method_already_implemented?("#{name}=")
+ if create_time_zone_conversion_attribute?(name, column)
+ define_write_method_for_time_zone_conversion(name)
+ else
+ define_write_method(name.to_sym)
+ end
+ end
+
+ unless instance_method_already_implemented?("#{name}?")
+ define_question_method(name)
+ end
+ end
+ end
+
+ # Checks whether the method is defined in the model or any of its subclasses
+ # that also derive from Active Record. Raises DangerousAttributeError if the
+ # method is defined by Active Record though.
+ def instance_method_already_implemented?(method_name)
+ method_name = method_name.to_s
+ return true if method_name =~ /^id(=$|\?$|$)/
+ @_defined_class_methods ||= ancestors.first(ancestors.index(ActiveRecord::Base)).sum([]) { |m| m.public_instance_methods(false) | m.private_instance_methods(false) | m.protected_instance_methods(false) }.map(&:to_s).to_set
+ @@_defined_activerecord_methods ||= (ActiveRecord::Base.public_instance_methods(false) | ActiveRecord::Base.private_instance_methods(false) | ActiveRecord::Base.protected_instance_methods(false)).map(&:to_s).to_set
+ raise DangerousAttributeError, "#{method_name} is defined by ActiveRecord" if @@_defined_activerecord_methods.include?(method_name)
+ @_defined_class_methods.include?(method_name)
+ end
+
+ alias :define_read_methods :define_attribute_methods
+
+ # +cache_attributes+ allows you to declare which converted attribute values should
+ # be cached. Usually caching only pays off for attributes with expensive conversion
+ # methods, like time related columns (e.g. +created_at+, +updated_at+).
+ def cache_attributes(*attribute_names)
+ attribute_names.each {|attr| cached_attributes << attr.to_s}
+ end
+
+ # Returns the attributes which are cached. By default time related columns
+ # with datatype <tt>:datetime, :timestamp, :time, :date</tt> are cached.
+ def cached_attributes
+ @cached_attributes ||=
+ columns.select{|c| attribute_types_cached_by_default.include?(c.type)}.map(&:name).to_set
+ end
+
+ # Returns +true+ if the provided attribute is being cached.
+ def cache_attribute?(attr_name)
+ cached_attributes.include?(attr_name)
+ end
+
+ private
+ # Suffixes a, ?, c become regexp /(a|\?|c)$/
+ def rebuild_attribute_method_regexp
+ suffixes = attribute_method_suffixes.map { |s| Regexp.escape(s) }
+ @@attribute_method_regexp = /(#{suffixes.join('|')})$/.freeze
+ end
+
+ # Default to =, ?, _before_type_cast
+ def attribute_method_suffixes
+ @@attribute_method_suffixes ||= []
+ end
+
+ def create_time_zone_conversion_attribute?(name, column)
+ time_zone_aware_attributes && !skip_time_zone_conversion_for_attributes.include?(name.to_sym) && [:datetime, :timestamp].include?(column.type)
+ end
+
+ # Define an attribute reader method. Cope with nil column.
+ def define_read_method(symbol, attr_name, column)
+ cast_code = column.type_cast_code('v') if column
+ access_code = cast_code ? "(v=@attributes['#{attr_name}']) && #{cast_code}" : "@attributes['#{attr_name}']"
+
+ unless attr_name.to_s == self.primary_key.to_s
+ access_code = access_code.insert(0, "missing_attribute('#{attr_name}', caller) unless @attributes.has_key?('#{attr_name}'); ")
+ end
+
+ if cache_attribute?(attr_name)
+ access_code = "@attributes_cache['#{attr_name}'] ||= (#{access_code})"
+ end
+ evaluate_attribute_method attr_name, "def #{symbol}; #{access_code}; end"
+ end
+
+ # Define read method for serialized attribute.
+ def define_read_method_for_serialized_attribute(attr_name)
+ evaluate_attribute_method attr_name, "def #{attr_name}; unserialize_attribute('#{attr_name}'); end"
+ end
+
+ # Defined for all +datetime+ and +timestamp+ attributes when +time_zone_aware_attributes+ are enabled.
+ # This enhanced read method automatically converts the UTC time stored in the database to the time zone stored in Time.zone.
+ def define_read_method_for_time_zone_conversion(attr_name)
+ method_body = <<-EOV
+ def #{attr_name}(reload = false)
+ cached = @attributes_cache['#{attr_name}']
+ return cached if cached && !reload
+ time = read_attribute('#{attr_name}')
+ @attributes_cache['#{attr_name}'] = time.acts_like?(:time) ? time.in_time_zone : time
+ end
+ EOV
+ evaluate_attribute_method attr_name, method_body
+ end
+
+ # Defines a predicate method <tt>attr_name?</tt>.
+ def define_question_method(attr_name)
+ evaluate_attribute_method attr_name, "def #{attr_name}?; query_attribute('#{attr_name}'); end", "#{attr_name}?"
+ end
+
+ def define_write_method(attr_name)
+ evaluate_attribute_method attr_name, "def #{attr_name}=(new_value);write_attribute('#{attr_name}', new_value);end", "#{attr_name}="
+ end
+
+ # Defined for all +datetime+ and +timestamp+ attributes when +time_zone_aware_attributes+ are enabled.
+ # This enhanced write method will automatically convert the time passed to it to the zone stored in Time.zone.
+ def define_write_method_for_time_zone_conversion(attr_name)
+ method_body = <<-EOV
+ def #{attr_name}=(time)
+ unless time.acts_like?(:time)
+ time = time.is_a?(String) ? Time.zone.parse(time) : time.to_time rescue time
+ end
+ time = time.in_time_zone rescue nil if time
+ write_attribute(:#{attr_name}, time)
+ end
+ EOV
+ evaluate_attribute_method attr_name, method_body, "#{attr_name}="
+ end
+
+ # Evaluate the definition for an attribute related method
+ def evaluate_attribute_method(attr_name, method_definition, method_name=attr_name)
+
+ unless method_name.to_s == primary_key.to_s
+ generated_methods << method_name
+ end
+
+ begin
+ class_eval(method_definition, __FILE__, __LINE__)
+ rescue SyntaxError => err
+ generated_methods.delete(attr_name)
+ if logger
+ logger.warn "Exception occurred during reader method compilation."
+ logger.warn "Maybe #{attr_name} is not a valid Ruby identifier?"
+ logger.warn err.message
+ end
+ end
+ end
+ end # ClassMethods
+
+
+ # Allows access to the object attributes, which are held in the <tt>@attributes</tt> hash, as though they
+ # were first-class methods. So a Person class with a name attribute can use Person#name and
+ # Person#name= and never directly use the attributes hash -- except for multiple assigns with
+ # ActiveRecord#attributes=. A Milestone class can also ask Milestone#completed? to test that
+ # the completed attribute is not +nil+ or 0.
+ #
+ # It's also possible to instantiate related objects, so a Client class belonging to the clients
+ # table with a +master_id+ foreign key can instantiate master through Client#master.
+ def method_missing(method_id, *args, &block)
+ method_name = method_id.to_s
+
+ if self.class.private_method_defined?(method_name)
+ raise NoMethodError.new("Attempt to call private method", method_name, args)
+ end
+
+ # If we haven't generated any methods yet, generate them, then
+ # see if we've created the method we're looking for.
+ if !self.class.generated_methods?
+ self.class.define_attribute_methods
+ if self.class.generated_methods.include?(method_name)
+ return self.send(method_id, *args, &block)
+ end
+ end
+
+ if self.class.primary_key.to_s == method_name
+ id
+ elsif md = self.class.match_attribute_method?(method_name)
+ attribute_name, method_type = md.pre_match, md.to_s
+ if @attributes.include?(attribute_name)
+ __send__("attribute#{method_type}", attribute_name, *args, &block)
+ else
+ super
+ end
+ elsif @attributes.include?(method_name)
+ read_attribute(method_name)
+ else
+ super
+ end
+ end
+
+ # Returns the value of the attribute identified by <tt>attr_name</tt> after it has been typecast (for example,
+ # "2004-12-12" in a data column is cast to a date object, like Date.new(2004, 12, 12)).
+ def read_attribute(attr_name)
+ attr_name = attr_name.to_s
+ if !(value = @attributes[attr_name]).nil?
+ if column = column_for_attribute(attr_name)
+ if unserializable_attribute?(attr_name, column)
+ unserialize_attribute(attr_name)
+ else
+ column.type_cast(value)
+ end
+ else
+ value
+ end
+ else
+ nil
+ end
+ end
+
+ def read_attribute_before_type_cast(attr_name)
+ @attributes[attr_name]
+ end
+
+ # Returns true if the attribute is of a text column and marked for serialization.
+ def unserializable_attribute?(attr_name, column)
+ column.text? && self.class.serialized_attributes[attr_name]
+ end
+
+ # Returns the unserialized object of the attribute.
+ def unserialize_attribute(attr_name)
+ unserialized_object = object_from_yaml(@attributes[attr_name])
+
+ if unserialized_object.is_a?(self.class.serialized_attributes[attr_name]) || unserialized_object.nil?
+ @attributes.frozen? ? unserialized_object : @attributes[attr_name] = unserialized_object
+ else
+ raise SerializationTypeMismatch,
+ "#{attr_name} was supposed to be a #{self.class.serialized_attributes[attr_name]}, but was a #{unserialized_object.class.to_s}"
+ end
+ end
+
+
+ # Updates the attribute identified by <tt>attr_name</tt> with the specified +value+. Empty strings for fixnum and float
+ # columns are turned into +nil+.
+ def write_attribute(attr_name, value)
+ attr_name = attr_name.to_s
+ @attributes_cache.delete(attr_name)
+ if (column = column_for_attribute(attr_name)) && column.number?
+ @attributes[attr_name] = convert_number_column_value(value)
+ else
+ @attributes[attr_name] = value
+ end
+ end
+
+
+ def query_attribute(attr_name)
+ unless value = read_attribute(attr_name)
+ false
+ else
+ column = self.class.columns_hash[attr_name]
+ if column.nil?
+ if Numeric === value || value !~ /[^0-9]/
+ !value.to_i.zero?
+ else
+ !value.blank?
+ end
+ elsif column.number?
+ !value.zero?
+ else
+ !value.blank?
+ end
+ end
+ end
+
+ # A Person object with a name attribute can ask <tt>person.respond_to?(:name)</tt>,
+ # <tt>person.respond_to?(:name=)</tt>, and <tt>person.respond_to?(:name?)</tt>
+ # which will all return +true+.
+ alias :respond_to_without_attributes? :respond_to?
+ def respond_to?(method, include_private_methods = false)
+ method_name = method.to_s
+ if super
+ return true
+ elsif !include_private_methods && super(method, true)
+ # If we're here than we haven't found among non-private methods
+ # but found among all methods. Which means that given method is private.
+ return false
+ elsif !self.class.generated_methods?
+ self.class.define_attribute_methods
+ if self.class.generated_methods.include?(method_name)
+ return true
+ end
+ end
+
+ if @attributes.nil?
+ return super
+ elsif @attributes.include?(method_name)
+ return true
+ elsif md = self.class.match_attribute_method?(method_name)
+ return true if @attributes.include?(md.pre_match)
+ end
+ super
+ end
+
+ private
+
+ def missing_attribute(attr_name, stack)
+ raise ActiveRecord::MissingAttributeError, "missing attribute: #{attr_name}", stack
+ end
+
+ # Handle *? for method_missing.
+ def attribute?(attribute_name)
+ query_attribute(attribute_name)
+ end
+
+ # Handle *= for method_missing.
+ def attribute=(attribute_name, value)
+ write_attribute(attribute_name, value)
+ end
+
+ # Handle *_before_type_cast for method_missing.
+ def attribute_before_type_cast(attribute_name)
+ read_attribute_before_type_cast(attribute_name)
+ end
+ end
+end
projects / depot.git / blobdiff