class Asciidoctor::PathResolver

def web_path target, start = nil

references removed
start path with any parent references resolved and self
returns a String path that joins the target path with the

start - the String start (i.e., parent) path
target - the String target path

That check should happen before this method is invoked.
The target is assumed to be a path, not a qualified URI.

references and remove any self references.
The main function of this operation is to resolve any parent
Public: Resolve a web path from the target and start paths. 
def web_path target, start = nil
  target = posixfy target
  start = posixfy start
  uri_prefix = nil
  unless start.nil_or_empty? || (is_web_root? target)
    target = %(#{start}#{SLASH}#{target})
    if (target.include? ':') && UriSniffRx =~ target
      uri_prefix = $~[0]
      target = target[uri_prefix.length..-1]
    end
  end
  # use this logic instead if we want to normalize target if it contains a URI
  #unless is_web_root? target
  #  if preserve_uri_target && (target.include? ':') && UriSniffRx =~ target
  #    uri_prefix = $~[0]
  #    target = target[uri_prefix.length..-1]
  #  elsif !start.nil_or_empty?
  #    target = %(#{start}#{SLASH}#{target})
  #    if (target.include? ':') && UriSniffRx =~ target
  #      uri_prefix = $~[0]
  #      target = target[uri_prefix.length..-1]
  #    end
  #  end
  #end
  target_segments, target_root, _ = partition_path target, true
  resolved_segments = []
  target_segments.each do |segment|
    if segment == DOT_DOT
      if resolved_segments.empty?
        resolved_segments << segment unless target_root && target_root != DOT_SLASH
      elsif resolved_segments[-1] == DOT_DOT
        resolved_segments << segment
      else
        resolved_segments.pop
      end
    else
      resolved_segments << segment
    end
  end
  if uri_prefix
    %(#{uri_prefix}#{join_path resolved_segments, target_root})
  else
    join_path resolved_segments, target_root
  end
end