sound_manager.lua

do
  -- will hold the currently playing sources
  local sources = {}

  -- check for sources that finished playing and remove them
  -- add to love.update
  function love.audio.update()
      local remove = {}
      for _,s in pairs(sources) do
          if s:isStopped() then
              remove[#remove + 1] = s
          end
      end

      for i,s in ipairs(remove) do
          sources[s] = nil
      end
  end

  -- overwrite love.audio.play to create and register source if needed
  local play = love.audio.play
  function love.audio.play(what, how, loop)
      local src = what
      if type(what) ~= "userdata" or not what:typeOf("Source") then
          src = love.audio.newSource(what, how)
          src:setLooping(loop or false)
      end

      play(src)
      sources[src] = src
      return src
  end

  -- stops a source
  local stop = love.audio.stop
  function love.audio.stop(src)
      if not src then return end
      stop(src)
      sources[src] = nil
  end
end