77 lines
1.9 KiB
Ruby
77 lines
1.9 KiB
Ruby
# frozen_string_literal: true
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module LooksAhead
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extend ActiveSupport::Concern
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included do
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extras [:lookahead]
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attr_accessor :lookahead
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end
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def resolve(**args)
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self.lookahead = args.delete(:lookahead)
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resolve_with_lookahead(**args)
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end
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def apply_lookahead(query)
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all_preloads = (unconditional_includes + filtered_preloads).uniq
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return query if all_preloads.empty?
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query.preload(*all_preloads) # rubocop: disable CodeReuse/ActiveRecord
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end
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private
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def unconditional_includes
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[]
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end
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def preloads
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{}
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end
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def nested_preloads
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{}
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end
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def filtered_preloads
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nodes = node_selection
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return [] unless nodes&.selected?
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selected_fields = nodes.selections.map(&:name)
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root_level_preloads = preloads_from_node_selection(selected_fields, preloads)
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root_level_preloads + nested_filtered_preloads(nodes, selected_fields)
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end
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def nested_filtered_preloads(nodes, selected_root_fields)
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return [] if nested_preloads.empty?
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nested_preloads.each_with_object([]) do |(root_field, fields), result|
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next unless selected_root_fields.include?(root_field)
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selected_fields = nodes.selection(root_field).selections.map(&:name)
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result << preloads_from_node_selection(selected_fields, fields)
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end.flatten
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end
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def preloads_from_node_selection(selected_fields, fields)
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fields.each_with_object([]) do |(field, requirements), result|
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result << requirements if selected_fields.include?(field)
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end.flatten
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end
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def node_selection(selection = lookahead)
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return selection unless selection&.selected?
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return selection.selection(:edges).selection(:node) if selection.selects?(:edges)
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# Will return a NullSelection object if :nodes is not a selection. This
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# is better than returning nil as we can continue chaining selections on
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# without raising errors.
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selection.selection(:nodes)
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end
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end
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