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Tasos Stathopoulos
8c1bbfec57
1.8.7 compatibility fix In Ruby 1.8.7, Hash does not preserve insertion ordering as Array does. This could cause a problem when registering filters which depend on others and the registration order is important. So, the @@filters variable was changed to array where the order of the filters is the same as the insertion order.
54 lines
1.5 KiB
Ruby
54 lines
1.5 KiB
Ruby
require 'set'
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module Liquid
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# Strainer is the parent class for the filters system.
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# New filters are mixed into the strainer class which is then instantiated for each liquid template render run.
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#
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# The Strainer only allows method calls defined in filters given to it via Strainer.global_filter,
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# Context#add_filters or Template.register_filter
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class Strainer #:nodoc:
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@@filters = []
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@@known_filters = Set.new
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@@known_methods = Set.new
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def initialize(context)
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@context = context
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end
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def self.global_filter(filter)
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raise ArgumentError, "Passed filter is not a module" unless filter.is_a?(Module)
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add_known_filter(filter)
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@@filters << filter unless @@filters.include?(filter)
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end
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def self.add_known_filter(filter)
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unless @@known_filters.include?(filter)
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@@method_blacklist ||= Set.new(Strainer.instance_methods.map(&:to_s))
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new_methods = filter.instance_methods.map(&:to_s)
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new_methods.reject!{ |m| @@method_blacklist.include?(m) }
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@@known_methods.merge(new_methods)
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@@known_filters.add(filter)
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end
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end
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def self.create(context)
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strainer = Strainer.new(context)
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@@filters.each { |m| strainer.extend(m) }
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strainer
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end
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def invoke(method, *args)
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if invokable?(method)
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send(method, *args)
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else
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args.first
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end
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end
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def invokable?(method)
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@@known_methods.include?(method.to_s) && respond_to?(method)
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end
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end
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end
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