1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
|
# frozen_string_literal: true
module Unparser
module Adamantium
# Build the memoized method
class MethodBuilder
# Raised when the method arity is invalid
class InvalidArityError < ArgumentError
# Initialize an invalid arity exception
#
# @param [Module] descendant
# @param [Symbol] method
# @param [Integer] arity
#
# @api private
def initialize(descendant, method, arity)
super("Cannot memoize #{descendant}##{method}, its arity is #{arity}")
end
end # InvalidArityError
# Raised when a block is passed to a memoized method
class BlockNotAllowedError < ArgumentError
# Initialize a block not allowed exception
#
# @param [Module] descendant
# @param [Symbol] method
#
# @api private
def initialize(descendant, method)
super("Cannot pass a block to #{descendant}##{method}, it is memoized")
end
end # BlockNotAllowedError
# Initialize an object to build a memoized method
#
# @param [Module] descendant
# @param [Symbol] method_name
#
# @return [undefined]
#
# @api private
def initialize(descendant, method_name)
@descendant = descendant
@method_name = method_name
@original_visibility = visibility
@original_method = @descendant.instance_method(@method_name)
assert_arity(@original_method.arity)
end
# Build a new memoized method
#
# @example
# method_builder.call # => creates new method
#
# @return [UnboundMethod]
#
# @api public
def call
remove_original_method
create_memoized_method
set_method_visibility
@original_method
end
private
def assert_arity(arity)
if arity.nonzero?
fail InvalidArityError.new(@descendant, @method_name, arity)
end
end
def remove_original_method
name = @method_name
@descendant.module_eval { undef_method(name) }
end
def create_memoized_method
name = @method_name
method = @original_method
@descendant.module_eval do
define_method(name) do |&block|
fail BlockNotAllowedError.new(self.class, name) if block
memoized_method_cache.fetch(name) do
method.bind(self).call.freeze
end
end
end
end
def set_method_visibility
@descendant.__send__(@original_visibility, @method_name)
end
def visibility
if @descendant.private_method_defined?(@method_name) then :private
elsif @descendant.protected_method_defined?(@method_name) then :protected
else
:public
end
end
end # MethodBuilder
end # Adamantium
end # Unparser
|
