54 lines
2.1 KiB
Ruby
54 lines
2.1 KiB
Ruby
# frozen_string_literal: true
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module Docile
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# @api private
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#
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# A namespace for functions relating to the execution of a block against a
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# proxy object.
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module Execution
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# Execute a block in the context of an object whose methods represent the
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# commands in a DSL, using a specific proxy class.
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#
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# @param dsl [Object] context object whose methods make up the
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# (initial) DSL
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# @param proxy_type [FallbackContextProxy, ChainingFallbackContextProxy]
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# which class to instantiate as proxy context
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# @param args [Array] arguments to be passed to the block
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# @param block [Proc] the block of DSL commands to be executed
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# @return [Object] the return value of the block
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def exec_in_proxy_context(dsl, proxy_type, *args, &block)
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block_context = eval("self", block.binding) # rubocop:disable Style/EvalWithLocation
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# Use #equal? to test strict object identity (assuming that this dictum
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# from the Ruby docs holds: "[u]nlike ==, the equal? method should never
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# be overridden by subclasses as it is used to determine object
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# identity")
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return dsl.instance_exec(*args, &block) if dsl.equal?(block_context)
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proxy_context = proxy_type.new(dsl, block_context)
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begin
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block_context.instance_variables.each do |ivar|
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value_from_block = block_context.instance_variable_get(ivar)
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proxy_context.instance_variable_set(ivar, value_from_block)
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end
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proxy_context.instance_exec(*args, &block)
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ensure
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if block_context.respond_to?(:__docile_undo_fallback__)
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block_context.send(:__docile_undo_fallback__)
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end
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block_context.instance_variables.each do |ivar|
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next unless proxy_context.instance_variables.include?(ivar)
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value_from_dsl_proxy = proxy_context.instance_variable_get(ivar)
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block_context.instance_variable_set(ivar, value_from_dsl_proxy)
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end
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end
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end
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ruby2_keywords :exec_in_proxy_context if respond_to?(:ruby2_keywords, true)
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module_function :exec_in_proxy_context
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end
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end
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