50 lines
1.2 KiB
Ruby
50 lines
1.2 KiB
Ruby
# frozen_string_literal: true
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module Gitlab
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module Pagination
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module Keyset
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class Pager < Gitlab::Pagination::Base
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attr_reader :request
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def initialize(request)
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@request = request
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end
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def paginate(relation)
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# Validate assumption: The last two columns must match the page order_by
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validate_order!(relation)
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relation.limit(page.per_page) # rubocop: disable CodeReuse/ActiveRecord
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end
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def finalize(records)
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apply_headers(records.last)
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end
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private
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def apply_headers(last_record_in_page)
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return unless last_record_in_page
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lower_bounds = last_record_in_page&.slice(page.order_by.keys)
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next_page = page.next(lower_bounds)
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request.apply_headers(next_page)
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end
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def page
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@page ||= request.page
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end
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def validate_order!(rel)
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present_order = rel.order_values.map { |val| [val.expr.name.to_sym, val.direction] }.last(2).to_h
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unless page.order_by == present_order
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raise ArgumentError, "Page's order_by does not match the relation's order: #{present_order} vs #{page.order_by}"
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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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end
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