# File lib/active_record/attribute_methods.rb, line 98 def attribute_method?(attribute) super || (table_exists? && column_names.include?(attribute.to_s.sub(/=$/, ''))) end
# File lib/active_record/attribute_methods.rb, line 49 def attribute_methods_generated? @attribute_methods_generated ||= false end
Returns an array of column names as strings if it's not an abstract class and table exists. Otherwise it returns an empty array.
# File lib/active_record/attribute_methods.rb, line 105 def attribute_names @attribute_names ||= if !abstract_class? && table_exists? column_names else [] end end
A method name is 'dangerous' if it is already defined by Active Record, but not by any ancestors. (So 'puts' is not dangerous but 'save' is.)
# File lib/active_record/attribute_methods.rb, line 82 def dangerous_attribute_method?(name) method_defined_within?(name, Base) end
Generates all the attribute related methods for columns in the database accessors, mutators and query methods.
# File lib/active_record/attribute_methods.rb, line 38 def define_attribute_methods # Use a mutex; we don't want two thread simaltaneously trying to define # attribute methods. @attribute_methods_mutex.synchronize do return if attribute_methods_generated? superclass.define_attribute_methods unless self == base_class super(column_names) @attribute_methods_generated = true end end
We will define the methods as instance methods, but will call them as singleton methods. This allows us to use method_defined? to check if the method exists, which is fast and won't give any false positives from the ancestors (because there are no ancestors).
# File lib/active_record/attribute_methods.rb, line 57 def generated_external_attribute_methods @generated_external_attribute_methods ||= Module.new { extend self } end
# File lib/active_record/attribute_methods.rb, line 66 def instance_method_already_implemented?(method_name) if dangerous_attribute_method?(method_name) raise DangerousAttributeError, "#{method_name} is defined by ActiveRecord" end if superclass == Base super else # If B < A and A defines its own attribute method, then we don't want to overwrite that. defined = method_defined_within?(method_name, superclass, superclass.generated_attribute_methods) defined && !ActiveRecord::Base.method_defined?(method_name) || super end end
# File lib/active_record/attribute_methods.rb, line 86 def method_defined_within?(name, klass, sup = klass.superclass) if klass.method_defined?(name) || klass.private_method_defined?(name) if sup.method_defined?(name) || sup.private_method_defined?(name) klass.instance_method(name).owner != sup.instance_method(name).owner else true end else false end end
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