95 lines
3 KiB
Ruby
95 lines
3 KiB
Ruby
# frozen_string_literal: true
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module Gitlab
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module Graphql
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module Pagination
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module Keyset
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class OrderInfo
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attr_reader :attribute_name, :sort_direction, :named_function
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def initialize(order_value)
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@attribute_name, @sort_direction, @named_function =
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if order_value.is_a?(String)
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extract_nulls_last_order(order_value)
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else
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extract_attribute_values(order_value)
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end
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end
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def operator_for(before_or_after)
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case before_or_after
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when :before
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sort_direction == :asc ? '<' : '>'
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when :after
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sort_direction == :asc ? '>' : '<'
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end
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end
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# Only allow specific node types
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def self.build_order_list(relation)
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order_list = relation.order_values.select do |value|
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supported_order_value?(value)
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end
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order_list.map { |info| OrderInfo.new(info) }
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end
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def self.validate_ordering(relation, order_list)
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if order_list.empty?
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raise ArgumentError.new('A minimum of 1 ordering field is required')
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end
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if order_list.count > 2
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raise ArgumentError.new('A maximum of 2 ordering fields are allowed')
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end
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# make sure the last ordering field is non-nullable
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attribute_name = order_list.last&.attribute_name
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if relation.columns_hash[attribute_name].null
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raise ArgumentError.new("Column `#{attribute_name}` must not allow NULL")
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end
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if order_list.last.attribute_name != relation.primary_key
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raise ArgumentError.new("Last ordering field must be the primary key, `#{relation.primary_key}`")
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end
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end
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def self.supported_order_value?(order_value)
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return true if order_value.is_a?(Arel::Nodes::Ascending) || order_value.is_a?(Arel::Nodes::Descending)
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return false unless order_value.is_a?(String)
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tokens = order_value.downcase.split
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tokens.last(2) == %w(nulls last) && tokens.count == 4
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end
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private
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def extract_nulls_last_order(order_value)
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tokens = order_value.downcase.split
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[tokens.first, (tokens[1] == 'asc' ? :asc : :desc), nil]
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end
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def extract_attribute_values(order_value)
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named = nil
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name = if ordering_by_lower?(order_value)
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named = order_value.expr
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named.expressions[0].name.to_s
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else
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order_value.expr.name
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end
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[name, order_value.direction, named]
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end
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# determine if ordering using LOWER, eg. "ORDER BY LOWER(boards.name)"
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def ordering_by_lower?(order_value)
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order_value.expr.is_a?(Arel::Nodes::NamedFunction) && order_value.expr&.name&.downcase == 'lower'
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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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