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Change the implementation of ActiveRecord's attribute reader and writer methods: 

* Generate Reader and Writer methods which cache attribute values in hashes.  This is to avoid repeatedly parsing the same date or integer columns.
 * Move the attribute related methods out to attribute_methods.rb to de-clutter base.rb
 * Change exception raised when users use find with :select then try to access a skipped column.  Plugins could override missing_attribute() to lazily load the columns.
 * Move method definition to the class, instead of the instance
 * Always generate the readers, writers and predicate methods.


git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@7315 5ecf4fe2-1ee6-0310-87b1-e25e094e27de
This commit is contained in:
Michael Koziarski 2007-08-14 08:53:02 +00:00
parent 55f444e694
commit 5b801b5960
6 changed files with 249 additions and 243 deletions
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221
activerecord/lib/active_record/attribute_methods.rb
View File

@ -43,6 +43,42 @@ module ActiveRecord
@@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_methods.include?(name)
if self.serialized_attributes[name]
define_read_method_for_serialized_attribute(name)
else
define_read_method(name.to_sym, name, column)
end
end
unless instance_methods.include?("#{name}=")
define_write_method(name.to_sym)
end
unless instance_methods.include?("#{name}?")
define_question_method(name)
end
end
end
alias :define_read_methods :define_attribute_methods
private
# Suffixes a, ?, c become regexp /(a|\?|c)$/
def rebuild_attribute_method_regexp
@ -54,9 +90,194 @@ module ActiveRecord
def attribute_method_suffixes
@@attribute_method_suffixes ||= []
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
evaluate_attribute_method attr_name, "def #{symbol}; @attributes_cache['#{attr_name}'] ||= begin; #{access_code}; end; 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
# Define an attribute ? method.
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
# 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)
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 @attributes hash, as were
# they 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 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[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 person.respond_to?("name"), person.respond_to?("name="), and
# person.respond_to?("name?") which will all return true.
alias :respond_to_without_attributes? :respond_to?
def respond_to?(method, include_priv = false)
method_name = method.to_s
if super
return true
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)

229
activerecord/lib/active_record/base.rb
View File

@ -35,6 +35,12 @@ module ActiveRecord #:nodoc:
end
class Rollback < StandardError #:nodoc:
end
# Raised when you've tried to access a column, which wasn't
# loaded by your finder. Typically this is because :select
# has been specified
class MissingAttributeError < NoMethodError
end
class AttributeAssignmentError < ActiveRecordError #:nodoc:
attr_reader :exception, :attribute
@ -342,13 +348,6 @@ module ActiveRecord #:nodoc:
cattr_accessor :allow_concurrency, :instance_writer => false
@@allow_concurrency = false
# Determines whether to speed up access by generating optimized reader
# methods to avoid expensive calls to method_missing when accessing
# attributes by name. You might want to set this to false in development
# mode, because the methods would be regenerated on each request.
cattr_accessor :generate_read_methods, :instance_writer => false
@@generate_read_methods = true
# Specifies the format to use when dumping the database schema with Rails'
# Rakefile. If :sql, the schema is dumped as (potentially database-
# specific) SQL statements. If :ruby, the schema is dumped as an
@ -875,15 +874,10 @@ module ActiveRecord #:nodoc:
end
end
# Contains the names of the generated reader methods.
def read_methods #:nodoc:
@read_methods ||= Set.new
end
# Resets all the cached information about columns, which will cause them to be reloaded on the next request.
def reset_column_information
read_methods.each { |name| undef_method(name) }
@column_names = @columns = @columns_hash = @content_columns = @dynamic_methods_hash = @read_methods = @inheritance_column = nil
generated_methods.each { |name| undef_method(name) }
@column_names = @columns = @columns_hash = @content_columns = @dynamic_methods_hash = @generated_methods = @inheritance_column = nil
end
def reset_column_information_and_inheritable_attributes_for_all_subclasses#:nodoc:
@ -1100,6 +1094,7 @@ module ActiveRecord #:nodoc:
end
object.instance_variable_set("@attributes", record)
object.instance_variable_set("@attributes_cache", Hash.new)
object
end
@ -1284,7 +1279,7 @@ module ActiveRecord #:nodoc:
def all_attributes_exists?(attribute_names)
attribute_names.all? { |name| column_methods_hash.include?(name.to_sym) }
end
end
def attribute_condition(argument)
case argument
@ -1639,6 +1634,7 @@ module ActiveRecord #:nodoc:
# hence you can't have attributes that aren't part of the table columns.
def initialize(attributes = nil)
@attributes = attributes_from_column_definition
@attributes_cache = {}
@new_record = true
ensure_proper_type
self.attributes = attributes unless attributes.nil?
@ -1652,13 +1648,10 @@ module ActiveRecord #:nodoc:
attr_name = self.class.primary_key
column = column_for_attribute(attr_name)
if self.class.generate_read_methods
define_read_method(:id, attr_name, column)
# now that the method exists, call it
self.send attr_name.to_sym
else
read_attribute(attr_name)
end
self.class.send(:define_read_method, :id, attr_name, column)
# now that the method exists, call it
self.send attr_name.to_sym
end
# Enables Active Record objects to be used as URL parameters in Action Pack automatically.
@ -1787,6 +1780,7 @@ module ActiveRecord #:nodoc:
clear_aggregation_cache
clear_association_cache
@attributes.update(self.class.find(self.id, options).instance_variable_get('@attributes'))
@attributes_cache = {}
self
end
@ -1902,27 +1896,6 @@ module ActiveRecord #:nodoc:
id.hash
end
# For checking respond_to? without searching the attributes (which is faster).
alias_method :respond_to_without_attributes?, :respond_to?
# A Person object with a name attribute can ask person.respond_to?("name"), person.respond_to?("name="), and
# person.respond_to?("name?") which will all return true.
def respond_to?(method, include_priv = false)
if @attributes.nil?
return super
elsif attr_name = self.class.column_methods_hash[method.to_sym]
return true if @attributes.include?(attr_name) || attr_name == self.class.primary_key
return false if self.class.read_methods.include?(attr_name)
elsif @attributes.include?(method_name = method.to_s)
return true
elsif md = self.class.match_attribute_method?(method.to_s)
return true if @attributes.include?(md.pre_match)
end
# super must be called at the end of the method, because the inherited respond_to?
# would return true for generated readers, even if the attribute wasn't present
super
end
# Just freeze the attributes hash, such that associations are still accessible even on destroyed records.
def freeze
@attributes.freeze; self
@ -1998,157 +1971,6 @@ module ActiveRecord #:nodoc:
end
end
# Allows access to the object attributes, which are held in the @attributes hash, as were
# they 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 @attributes.include?(method_name) or
(md = /\?$/.match(method_name) and
@attributes.include?(query_method_name = md.pre_match) and
method_name = query_method_name)
if self.class.read_methods.empty? && self.class.generate_read_methods
define_read_methods
# now that the method exists, call it
self.send method_id.to_sym
else
md ? query_attribute(method_name) : read_attribute(method_name)
end
elsif 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
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
# Called on first read access to any given column and generates reader
# methods for all columns in the columns_hash if
# ActiveRecord::Base.generate_read_methods is set to true.
def define_read_methods
self.class.columns_hash.each do |name, column|
unless respond_to_without_attributes?(name)
if self.class.serialized_attributes[name]
define_read_method_for_serialized_attribute(name)
else
define_read_method(name.to_sym, name, column)
end
end
unless respond_to_without_attributes?("#{name}?")
define_question_method(name)
end
end
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.class.primary_key.to_s
access_code = access_code.insert(0, "raise NoMethodError, 'missing attribute: #{attr_name}', caller unless @attributes.has_key?('#{attr_name}'); ")
self.class.read_methods << attr_name
end
evaluate_read_method attr_name, "def #{symbol}; #{access_code}; end"
end
# Define read method for serialized attribute.
def define_read_method_for_serialized_attribute(attr_name)
unless attr_name.to_s == self.class.primary_key.to_s
self.class.read_methods << attr_name
end
evaluate_read_method attr_name, "def #{attr_name}; unserialize_attribute('#{attr_name}'); end"
end
# Define an attribute ? method.
def define_question_method(attr_name)
unless attr_name.to_s == self.class.primary_key.to_s
self.class.read_methods << "#{attr_name}?"
end
evaluate_read_method attr_name, "def #{attr_name}?; query_attribute('#{attr_name}'); end"
end
# Evaluate the definition for an attribute reader or ? method
def evaluate_read_method(attr_name, method_definition)
begin
self.class.class_eval(method_definition)
rescue SyntaxError => err
self.class.read_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
# 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[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
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 convert_number_column_value(value)
case value
when FalseClass: 0
@ -2158,25 +1980,6 @@ module ActiveRecord #:nodoc:
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
def remove_attributes_protected_from_mass_assignment(attributes)
if self.class.accessible_attributes.nil? && self.class.protected_attributes.nil?
attributes.reject { |key, value| attributes_protected_by_default.include?(key.gsub(/\(.+/, "")) }

3
activerecord/lib/active_record/transactions.rb
View File

@ -121,7 +121,8 @@ module ActiveRecord
self.id = previous_id
else
@attributes.delete(self.class.primary_key)
end
@attributes_cache.delete(self.class.primary_key)
end
raise
end
end

6
activerecord/test/associations_test.rb
View File

@ -1470,10 +1470,12 @@ class HasAndBelongsToManyAssociationsTest < Test::Unit::TestCase
assert project.respond_to?("name=")
assert project.respond_to?("name?")
assert project.respond_to?("joined_on")
assert project.respond_to?("joined_on=")
# given that the 'join attribute' won't be persisted, I don't
# think we should define the mutators
#assert project.respond_to?("joined_on=")
assert project.respond_to?("joined_on?")
assert project.respond_to?("access_level")
assert project.respond_to?("access_level=")
#assert project.respond_to?("access_level=")
assert project.respond_to?("access_level?")
end

28
activerecord/test/base_test.rb
View File

@ -344,24 +344,10 @@ class BasicsTest < Test::Unit::TestCase
assert !object.int_value?
end
def test_reader_generation
Topic.find(:first).title
Firm.find(:first).name
Client.find(:first).name
if ActiveRecord::Base.generate_read_methods
assert_readers(Topic, %w(type replies_count))
assert_readers(Firm, %w(type))
assert_readers(Client, %w(type ruby_type rating?))
else
[Topic, Firm, Client].each {|klass| assert_equal klass.read_methods, {}}
end
end
def test_reader_for_invalid_column_names
# column names which aren't legal ruby ids
topic = Topic.find(:first)
topic.send(:define_read_method, "mumub-jumbo".to_sym, "mumub-jumbo", nil)
assert !Topic.read_methods.include?("mumub-jumbo")
Topic.send(:define_read_method, "mumub-jumbo".to_sym, "mumub-jumbo", nil)
assert !Topic.generated_methods.include?("mumub-jumbo")
end
def test_non_attribute_access_and_assignment
@ -791,7 +777,7 @@ class BasicsTest < Test::Unit::TestCase
def test_mass_assignment_protection_against_class_attribute_writers
[:logger, :configurations, :primary_key_prefix_type, :table_name_prefix, :table_name_suffix, :pluralize_table_names, :colorize_logging,
:default_timezone, :allow_concurrency, :generate_read_methods, :schema_format, :verification_timeout, :lock_optimistically, :record_timestamps].each do |method|
:default_timezone, :allow_concurrency, :schema_format, :verification_timeout, :lock_optimistically, :record_timestamps].each do |method|
assert Task.respond_to?(method)
assert Task.respond_to?("#{method}=")
assert Task.new.respond_to?(method)
@ -1708,12 +1694,4 @@ class BasicsTest < Test::Unit::TestCase
assert_equal %("#{t.written_on.to_s(:db)}"), t.attribute_for_inspect(:written_on)
assert_equal '"This is some really long content, longer than 50 ch..."', t.attribute_for_inspect(:content)
end
private
def assert_readers(model, exceptions)
expected_readers = Set.new(model.column_names - ['id'])
expected_readers += expected_readers.map { |col| "#{col}?" }
expected_readers -= exceptions
assert_equal expected_readers, model.read_methods
end
end

5
activerecord/test/finder_test.rb
View File

@ -1,4 +1,5 @@
require 'abstract_unit'
require 'fixtures/author'
require 'fixtures/comment'
require 'fixtures/company'
require 'fixtures/topic'
@ -129,10 +130,10 @@ class FinderTest < Test::Unit::TestCase
def test_find_only_some_columns
topic = Topic.find(1, :select => "author_name")
assert_raises(NoMethodError) { topic.title }
assert_raises(ActiveRecord::MissingAttributeError) {topic.title}
assert_equal "David", topic.author_name
assert !topic.attribute_present?("title")
assert !topic.respond_to?("title")
#assert !topic.respond_to?("title")
assert topic.attribute_present?("author_name")
assert topic.respond_to?("author_name")
end