84 lines
2 KiB
Ruby
84 lines
2 KiB
Ruby
# frozen_string_literal: true
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module Gitlab
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module RelativePositioning
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IllegalRange = Class.new(ArgumentError)
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class Range
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attr_reader :lhs, :rhs
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def open_on_left?
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lhs.nil?
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end
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def open_on_right?
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rhs.nil?
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end
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def cover?(item_context)
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return false unless item_context
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return false unless item_context.positioned?
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return true if item_context.object == lhs&.object
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return true if item_context.object == rhs&.object
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pos = item_context.relative_position
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return lhs.relative_position < pos if open_on_right?
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return pos < rhs.relative_position if open_on_left?
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lhs.relative_position < pos && pos < rhs.relative_position
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end
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def ==(other)
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other.is_a?(RelativePositioning::Range) && lhs == other.lhs && rhs == other.rhs
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end
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end
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def self.range(lhs, rhs)
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if lhs && rhs
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ClosedRange.new(lhs, rhs)
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elsif lhs
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StartingFrom.new(lhs)
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elsif rhs
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EndingAt.new(rhs)
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else
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raise IllegalRange, 'One of rhs or lhs must be provided' unless lhs && rhs
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end
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end
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class ClosedRange < RelativePositioning::Range
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def initialize(lhs, rhs)
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@lhs, @rhs = lhs, rhs
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raise IllegalRange, 'Either lhs or rhs is missing' unless lhs && rhs
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raise IllegalRange, 'lhs and rhs cannot be the same object' if lhs == rhs
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end
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end
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class StartingFrom < RelativePositioning::Range
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include Gitlab::Utils::StrongMemoize
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def initialize(lhs)
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@lhs = lhs
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raise IllegalRange, 'lhs is required' unless lhs
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end
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def rhs
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strong_memoize(:rhs) { lhs.rhs_neighbour }
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end
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end
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class EndingAt < RelativePositioning::Range
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include Gitlab::Utils::StrongMemoize
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def initialize(rhs)
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@rhs = rhs
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raise IllegalRange, 'rhs is required' unless rhs
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end
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def lhs
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strong_memoize(:lhs) { rhs.lhs_neighbour }
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end
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end
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end
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end
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