59 lines
1.5 KiB
Ruby
59 lines
1.5 KiB
Ruby
# frozen_string_literal: true
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# Released under the MIT License.
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# Copyright, 2023, by Samuel Williams.
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require 'fiber'
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class Fiber
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# A mechanism for annotating fibers.
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module Annotation
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# Annotate the current fiber with the given annotation.
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# @parameter annotation [Object] The annotation to set.
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def initialize(annotation: nil, **options, &block)
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@annotation = annotation
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super(**options, &block)
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end
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# Get the current annotation.
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# @returns [Object] The current annotation.
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attr_accessor :annotation
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# Annotate the current fiber with the given annotation.
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#
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# If a block is given, the annotation is set for the duration of the block and then restored to the previous value.
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#
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# The block form of this method should only be invoked on the current fiber.
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#
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# @parameter annotation [Object] The annotation to set.
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# @yields {} The block to execute with the given annotation.
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# @returns [Object] The return value of the block.
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def annotate(annotation)
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if block_given?
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raise "Cannot annotation a different fiber!" unless Fiber.current == self
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begin
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current_annotation = @annotation
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@annotation = annotation
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return yield
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ensure
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@annotation = current_annotation
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end
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else
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@annotation = annotation
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end
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end
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end
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end
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unless Fiber.method_defined?(:annotation)
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Fiber.prepend(Fiber::Annotation)
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# @scope Fiber
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# @name self.annotate
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# Annotate the current fiber with the given annotation.
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def Fiber.annotate(...)
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Fiber.current.annotate(...)
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end
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end
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