125 lines
4.6 KiB
Ruby
125 lines
4.6 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, '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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# Keep in mind an order clause for primary key is added if one is not present
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# lib/gitlab/graphql/pagination/keyset/connection.rb:97
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raise ArgumentError, '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, "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, "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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column_reference = tokens.first
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sort_direction = tokens[1] == 'asc' ? :asc : :desc
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# Handles the case when the order value is coming from another table.
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# Example: table_name.column_name
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# Query the value using the fully qualified column name: pass table_name.column_name as the named_function
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if fully_qualified_column_reference?(column_reference)
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[column_reference, sort_direction, Arel.sql(column_reference)]
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else
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[column_reference, sort_direction, nil]
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end
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end
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# Example: table_name.column_name
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def fully_qualified_column_reference?(attribute)
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attribute.to_s.count('.') == 1
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end
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def extract_attribute_values(order_value)
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if ordering_by_lower?(order_value)
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[order_value.expr.expressions[0].name.to_s, order_value.direction, order_value.expr]
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elsif ordering_by_case?(order_value)
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['case_order_value', order_value.direction, order_value.expr]
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elsif ordering_by_array_position?(order_value)
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['array_position', order_value.direction, order_value.expr]
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else
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[order_value.expr.name, order_value.direction, nil]
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end
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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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# determine if ordering using ARRAY_POSITION, eg. "ORDER BY ARRAY_POSITION(Array[4,3,1,2]::smallint, state)"
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def ordering_by_array_position?(order_value)
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order_value.expr.is_a?(Arel::Nodes::NamedFunction) && order_value.expr&.name&.downcase == 'array_position'
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end
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# determine if ordering using CASE
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def ordering_by_case?(order_value)
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order_value.expr.is_a?(Arel::Nodes::Case)
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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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Gitlab::Graphql::Pagination::Keyset::OrderInfo.prepend_mod_with('Gitlab::Graphql::Pagination::Keyset::OrderInfo')
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