# frozen_string_literal: true
module SyntaxSuggest
# Keeps track of what elements are in the queue in
# priority and also ensures that when one element
# engulfs/covers/eats another that the larger element
# evicts the smaller element
class PriorityEngulfQueue
def initialize
@queue = PriorityQueue.new
end
def to_a
@queue.to_a
end
def empty?
@queue.empty?
end
def length
@queue.length
end
def peek
@queue.peek
end
def pop
@queue.pop
end
def push(block)
prune_engulf(block)
@queue << block
flush_deleted
self
end
private def flush_deleted
while @queue&.peek&.deleted?
@queue.pop
end
end
private def prune_engulf(block)
# If we're about to pop off the same block, we can skip deleting
# things from the frontier this iteration since we'll get it
# on the next iteration
return if @queue.peek && (block <=> @queue.peek) == 1
if block.starts_at != block.ends_at # A block of size 1 cannot engulf another
@queue.to_a.each { |b|
if b.starts_at >= block.starts_at && b.ends_at <= block.ends_at
b.delete
true
end
}
end
end
end
end
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