63 lines
2.0 KiB
Ruby
63 lines
2.0 KiB
Ruby
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module ThreadSafe
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module Util
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module Volatile
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# Provides +volatile+ (in the JVM's sense) attribute accessors implemented atop of the +AtomicReference+s.
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# Usage:
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# class Foo
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# extend ThreadSafe::Util::Volatile
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# attr_volatile :foo, :bar
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#
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# def initialize(bar)
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# super() # must super() into parent initializers before using the volatile attribute accessors
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# self.bar = bar
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# end
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#
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# def hello
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# my_foo = foo # volatile read
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# self.foo = 1 # volatile write
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# cas_foo(1, 2) # => true | a strong CAS
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# end
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# end
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def attr_volatile(*attr_names)
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return if attr_names.empty?
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include(Module.new do
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atomic_ref_setup = attr_names.map {|attr_name| "@__#{attr_name} = ThreadSafe::Util::AtomicReference.new"}
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initialize_copy_setup = attr_names.zip(atomic_ref_setup).map do |attr_name, ref_setup|
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"#{ref_setup}(other.instance_variable_get(:@__#{attr_name}).get)"
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end
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class_eval <<-RUBY_EVAL, __FILE__, __LINE__ + 1
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def initialize(*)
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super
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#{atomic_ref_setup.join('; ')}
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end
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def initialize_copy(other)
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super
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#{initialize_copy_setup.join('; ')}
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end
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RUBY_EVAL
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attr_names.each do |attr_name|
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class_eval <<-RUBY_EVAL, __FILE__, __LINE__ + 1
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def #{attr_name}
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@__#{attr_name}.get
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end
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def #{attr_name}=(value)
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@__#{attr_name}.set(value)
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end
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def compare_and_set_#{attr_name}(old_value, new_value)
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@__#{attr_name}.compare_and_set(old_value, new_value)
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end
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RUBY_EVAL
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alias_method :"cas_#{attr_name}", :"compare_and_set_#{attr_name}"
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alias_method :"lazy_set_#{attr_name}", :"#{attr_name}="
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end
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end)
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end
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end
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end
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end
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