function parseQueryString(str)
{
  if (str == "")
    return {};

  var paramArray = str.split("&");
  var regex = /^([^=]+)=(.*)$/;
  var params = {};
  for (var i = 0, sz = paramArray.length; i < sz; i++)
  {
    var match = regex.exec(paramArray[i]);
    if (!match)
      throw "Bad parameter in queryString!  '" + paramArray[i] + "'";
    params[decodeURIComponent(match[1])] = decodeURIComponent(match[2]);
  }

  return params;
}

function getPosition(action)
{
  var response = {
    status: "OK",
    location: {
      lat: 37.41857,
      lng: -122.08769,
    },
    accuracy: (action == "worse-accuracy") ? 100 : 42,
  };

  return JSON.stringify(response);
}

var timer;
function handleRequest(request, response)
{
  var params = parseQueryString(request.queryString);

  if (params.action == "stop-responding") {
      response.processAsync();
      return;
  }

  var position = getPosition(params.action);

  if (params.action == "respond-garbage") {
     // better way?
    var chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXTZabcdefghiklmnopqrstuvwxyz";
    position = "";
    var len = Math.floor(Math.random() * 5000);

    for (var i=0; i< len; i++) {
        var c = Math.floor(Math.random() * chars.length);
        position += chars.substring(c, c+1);
    }
  }

  var response;
  response.processAsync();
  response.setStatusLine("1.0", 200, "OK");
  response.setHeader("Cache-Control", "no-cache", false);
  response.setHeader("Content-Type", "aplication/x-javascript", false);

  var delay = 0;
  if ('delay' in params) {
    delay = params.delay;
  }
  if (params.action === "send404") {
    response.setStatusLine("1.0", 404, "Not Found");
    position = '';
  }
  timer = Components.classes["@mozilla.org/timer;1"].createInstance(Components.interfaces.nsITimer);
  timer.initWithCallback(function() {
    response.write(position);
    response.finish();
  }, delay, timer.TYPE_ONE_SHOT);
}