123 lines
2.2 KiB
Ruby
123 lines
2.2 KiB
Ruby
class BasePolicy
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class RuleSet
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attr_reader :can_set, :cannot_set
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def initialize(can_set, cannot_set)
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@can_set = can_set
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@cannot_set = cannot_set
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end
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delegate :size, to: :to_set
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def self.empty
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new(Set.new, Set.new)
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end
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def self.none
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empty.freeze
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end
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def can?(ability)
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@can_set.include?(ability) && !@cannot_set.include?(ability)
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end
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def include?(ability)
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can?(ability)
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end
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def to_set
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@can_set - @cannot_set
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end
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def merge(other)
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@can_set.merge(other.can_set)
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@cannot_set.merge(other.cannot_set)
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end
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def can!(*abilities)
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@can_set.merge(abilities)
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end
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def cannot!(*abilities)
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@cannot_set.merge(abilities)
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end
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def freeze
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@can_set.freeze
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@cannot_set.freeze
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super
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end
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end
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def self.abilities(user, subject)
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new(user, subject).abilities
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end
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def self.class_for(subject)
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return GlobalPolicy if subject == :global
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raise ArgumentError, 'no policy for nil' if subject.nil?
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if subject.class.try(:presenter?)
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subject = subject.subject
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end
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subject.class.ancestors.each do |klass|
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next unless klass.name
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begin
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policy_class = "#{klass.name}Policy".constantize
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# NOTE: the < operator here tests whether policy_class
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# inherits from BasePolicy
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return policy_class if policy_class < BasePolicy
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rescue NameError
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nil
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end
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end
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raise "no policy for #{subject.class.name}"
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end
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attr_reader :user, :subject
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def initialize(user, subject)
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@user = user
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@subject = subject
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end
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def abilities
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return RuleSet.none if @user && @user.blocked?
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return anonymous_abilities if @user.nil?
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collect_rules { rules }
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end
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def anonymous_abilities
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collect_rules { anonymous_rules }
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end
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def anonymous_rules
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rules
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end
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def delegate!(new_subject)
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@rule_set.merge(Ability.allowed(@user, new_subject))
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end
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def can?(rule)
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@rule_set.can?(rule)
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end
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def can!(*rules)
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@rule_set.can!(*rules)
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end
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def cannot!(*rules)
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@rule_set.cannot!(*rules)
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end
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private
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def collect_rules(&b)
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@rule_set = RuleSet.empty
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yield
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@rule_set
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end
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end
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