75 lines
1.9 KiB
Ruby
75 lines
1.9 KiB
Ruby
# frozen_string_literal: true
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module Gitlab
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module Graphql
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module Loaders
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class LazyRelationLoader
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class << self
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attr_accessor :model, :association
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# Automatically register the inheriting
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# classes to GitlabSchema as lazy objects.
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def inherited(klass)
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GitlabSchema.lazy_resolve(klass, :load)
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end
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end
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def initialize(query_ctx, object, **kwargs)
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@query_ctx = query_ctx
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@object = object
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@kwargs = kwargs
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query_ctx[loader_cache_key] ||= Registry.new(relation(**kwargs))
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query_ctx[loader_cache_key].register(object)
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end
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# Returns an instance of `RelationProxy` for the object (parent model).
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# The returned object behaves like an Active Record relation to support
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# keyset pagination.
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def load
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case reflection.macro
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when :has_many
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relation_proxy
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when :has_one
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relation_proxy.last
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else
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raise 'Not supported association type!'
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end
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end
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private
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attr_reader :query_ctx, :object, :kwargs
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delegate :model, :association, to: :"self.class"
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# Implement this one if you want to filter the relation
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def relation(**)
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base_relation
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end
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def loader_cache_key
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@loader_cache_key ||= self.class.name.to_s + kwargs.sort.to_s
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end
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def base_relation
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placeholder_record.association(association).scope
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end
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# This will only work for HasMany and HasOne associations for now
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def placeholder_record
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model.new(reflection.active_record_primary_key => 0)
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end
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def reflection
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model.reflections[association.to_s]
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end
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def relation_proxy
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RelationProxy.new(object, query_ctx[loader_cache_key])
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end
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end
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end
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end
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end
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