module Sprockets::PathUtils

def match_path_extname(path, extensions)

Returns [String extname, Object value] or nil nothing matched.

extensions - Hash of String extnames to values
path - String

Internal: Match path extnames against available extensions. 
def match_path_extname(path, extensions)
  basename = File.basename(path)
  i = basename.index('.'.freeze)
  while i && i < basename.length - 1
    extname = basename[i..-1]
    if value = extensions[extname]
      return extname, value
    end
    i = basename.index('.'.freeze, i+1)
  end
  nil
end