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# frozen_string_literal: true
require 'memoist/version'
module Memoist
def self.extended(extender)
Memoist.memoist_eval(extender) do
unless singleton_class.method_defined?(:memoized_methods)
def self.memoized_methods
@_memoized_methods ||= []
end
end
end
end
def self.memoized_ivar_for(method_name, identifier = nil)
"@#{memoized_prefix(identifier)}_#{escape_punctuation(method_name)}"
end
def self.unmemoized_method_for(method_name, identifier = nil)
"#{unmemoized_prefix(identifier)}_#{method_name}".to_sym
end
def self.memoized_prefix(identifier = nil)
if identifier
"_memoized_#{identifier}"
else
'_memoized'.freeze
end
end
def self.unmemoized_prefix(identifier = nil)
if identifier
"_unmemoized_#{identifier}"
else
'_unmemoized'.freeze
end
end
def self.escape_punctuation(string)
string = string.is_a?(String) ? string.dup : string.to_s.dup
return string unless string.end_with?('?'.freeze, '!'.freeze)
# A String can't end in both ? and !
if string.sub!(/\?\Z/, '_query'.freeze)
else
string.sub!(/!\Z/, '_bang'.freeze)
end
string
end
def self.memoist_eval(klass, *args, &block)
if klass.respond_to?(:class_eval)
klass.class_eval(*args, &block)
else
klass.singleton_class.class_eval(*args, &block)
end
end
def self.extract_reload!(method, args)
if args.length == method.arity.abs + 1 && (args.last == true || args.last == :reload)
reload = args.pop
end
reload
end
module InstanceMethods
def memoize_all
prime_cache
end
def unmemoize_all
flush_cache
end
def memoized_structs(names)
ref_obj = self.class.respond_to?(:class_eval) ? singleton_class : self
structs = ref_obj.all_memoized_structs
return structs if names.empty?
structs.select { |s| names.include?(s.memoized_method) }
end
def prime_cache(*method_names)
memoized_structs(method_names).each do |struct|
if struct.arity == 0
__send__(struct.memoized_method)
else
instance_variable_set(struct.ivar, {})
end
end
end
def flush_cache(*method_names)
memoized_structs(method_names).each do |struct|
remove_instance_variable(struct.ivar) if instance_variable_defined?(struct.ivar)
end
end
end
MemoizedMethod = Struct.new(:memoized_method, :ivar, :arity)
def all_memoized_structs
@all_memoized_structs ||= begin
structs = memoized_methods.dup
# Collect the memoized_methods of ancestors in ancestor order
# unless we already have it since self or parents could be overriding
# an ancestor method.
ancestors.grep(Memoist).each do |ancestor|
ancestor.memoized_methods.each do |m|
structs << m unless structs.any? { |am| am.memoized_method == m.memoized_method }
end
end
structs
end
end
def clear_structs
@all_memoized_structs = nil
end
def memoize(*method_names)
identifier = method_names.pop[:identifier] if method_names.last.is_a?(Hash)
method_names.each do |method_name|
unmemoized_method = Memoist.unmemoized_method_for(method_name, identifier)
memoized_ivar = Memoist.memoized_ivar_for(method_name, identifier)
Memoist.memoist_eval(self) do
include InstanceMethods
if method_defined?(unmemoized_method)
warn "Already memoized #{method_name}"
return
end
alias_method unmemoized_method, method_name
mm = MemoizedMethod.new(method_name, memoized_ivar, instance_method(method_name).arity)
memoized_methods << mm
if mm.arity == 0
# define a method like this;
# def mime_type(reload=true)
# skip_cache = reload || !instance_variable_defined?("@_memoized_mime_type")
# set_cache = skip_cache && !frozen?
#
# if skip_cache
# value = _unmemoized_mime_type
# else
# value = @_memoized_mime_type
# end
#
# if set_cache
# @_memoized_mime_type = value
# end
#
# value
# end
module_eval <<-EOS, __FILE__, __LINE__ + 1
def #{method_name}(reload = false)
skip_cache = reload || !instance_variable_defined?("#{memoized_ivar}")
set_cache = skip_cache && !frozen?
if skip_cache
value = #{unmemoized_method}
else
value = #{memoized_ivar}
end
if set_cache
#{memoized_ivar} = value
end
value
end
EOS
else
# define a method like this;
# def mime_type(*args)
# reload = Memoist.extract_reload!(method(:_unmemoized_mime_type), args)
#
# skip_cache = reload || !memoized_with_args?(:mime_type, args)
# set_cache = skip_cache && !frozen
#
# if skip_cache
# value = _unmemoized_mime_type(*args)
# else
# value = @_memoized_mime_type[args]
# end
#
# if set_cache
# @_memoized_mime_type ||= {}
# @_memoized_mime_type[args] = value
# end
#
# value
# end
module_eval <<-EOS, __FILE__, __LINE__ + 1
def #{method_name}(*args)
reload = Memoist.extract_reload!(method(#{unmemoized_method.inspect}), args)
skip_cache = reload || !(instance_variable_defined?(#{memoized_ivar.inspect}) && #{memoized_ivar} && #{memoized_ivar}.has_key?(args))
set_cache = skip_cache && !frozen?
if skip_cache
value = #{unmemoized_method}(*args)
else
value = #{memoized_ivar}[args]
end
if set_cache
#{memoized_ivar} ||= {}
#{memoized_ivar}[args] = value
end
value
end
EOS
end
if private_method_defined?(unmemoized_method)
private method_name
elsif protected_method_defined?(unmemoized_method)
protected method_name
end
end
end
# return a chainable method_name symbol if we can
method_names.length == 1 ? method_names.first : method_names
end
end
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