d598e4fd93
Enables frozen for the following: * lib/*.rb * lib/banzai/**/*.rb * lib/bitbucket/**/*.rb * lib/constraints/**/*.rb * lib/container_registry/**/*.rb * lib/declarative_policy/**/*.rb Partially addresses #47424.
105 lines
3.4 KiB
Ruby
105 lines
3.4 KiB
Ruby
# frozen_string_literal: true
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module DeclarativePolicy
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# A Condition is the data structure that is created by the
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# `condition` declaration on DeclarativePolicy::Base. It is
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# more or less just a struct of the data passed to that
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# declaration. It holds on to the block to be instance_eval'd
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# on a context (instance of Base) later, via #compute.
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class Condition
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attr_reader :name, :description, :scope
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attr_reader :manual_score
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attr_reader :context_key
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def initialize(name, opts = {}, &compute)
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@name = name
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@compute = compute
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@scope = opts.fetch(:scope, :normal)
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@description = opts.delete(:description)
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@context_key = opts[:context_key]
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@manual_score = opts.fetch(:score, nil)
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end
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def compute(context)
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!!context.instance_eval(&@compute)
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end
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def key
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"#{@context_key}/#{@name}"
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end
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end
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# In contrast to a Condition, a ManifestCondition contains
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# a Condition and a context object, and is capable of calculating
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# a result itself. This is the return value of Base#condition.
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class ManifestCondition
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def initialize(condition, context)
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@condition = condition
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@context = context
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end
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# The main entry point - does this condition pass? We reach into
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# the context's cache here so that we can share in the global
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# cache (often RequestStore or similar).
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def pass?
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@context.cache(cache_key) { @condition.compute(@context) }
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end
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# Whether we've already computed this condition.
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def cached?
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@context.cached?(cache_key)
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end
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# This is used to score Rule::Condition. See Rule::Condition#score
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# and Runner#steps_by_score for how scores are used.
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#
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# The number here is intended to represent, abstractly, how
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# expensive it would be to calculate this condition.
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#
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# See #cache_key for info about @condition.scope.
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def score
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# If we've been cached, no computation is necessary.
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return 0 if cached?
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# Use the override from condition(score: ...) if present
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return @condition.manual_score if @condition.manual_score
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# Global scope rules are cheap due to max cache sharing
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return 2 if @condition.scope == :global
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# "Normal" rules can't share caches with any other policies
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return 16 if @condition.scope == :normal
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# otherwise, we're :user or :subject scope, so it's 4 if
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# the caller has declared a preference
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return 4 if @condition.scope == DeclarativePolicy.preferred_scope
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# and 8 for all other :user or :subject scope conditions.
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8
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end
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private
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# This method controls the caching for the condition. This is where
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# the condition(scope: ...) option comes into play. Notice that
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# depending on the scope, we may cache only by the user or only by
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# the subject, resulting in sharing across different policy objects.
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def cache_key
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@cache_key ||=
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case @condition.scope
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when :normal then "/dp/condition/#{@condition.key}/#{user_key},#{subject_key}"
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when :user then "/dp/condition/#{@condition.key}/#{user_key}"
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when :subject then "/dp/condition/#{@condition.key}/#{subject_key}"
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when :global then "/dp/condition/#{@condition.key}"
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else raise 'invalid scope'
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end
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end
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def user_key
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Cache.user_key(@context.user)
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end
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def subject_key
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Cache.subject_key(@context.subject)
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end
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end
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end
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