"use strict";

const IMG_BYTES = atob(

  "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAA" +

  "DUlEQVQImWNgY2P7DwABOgESJhRQtgAAAABJRU5ErkJggg==");

function handleRequest(request, response) {

  response.processAsync();

  getObjectState("context", function(obj) {

    let ctx;

    if (obj == null) {

      ctx = {

        QueryInterface: function(iid) {

          if (iid.equals(Components.interfaces.nsISupports))

            return this;

          throw Components.results.NS_ERROR_NO_INTERFACE;

        }

      };

      ctx.wrappedJSObject = ctx;

      ctx.promise = new Promise(resolve => {

        ctx.resolve = resolve;

      });

      setObjectState("context", ctx);

    } else {

      ctx = obj.wrappedJSObject;

    }

    Promise.resolve(ctx).then(next);

  });

  function next(ctx) {

    if (request.queryString.indexOf("continue") >= 0) {

      ctx.resolve();

    }

    ctx.promise.then(() => {

      response.setHeader("Content-Type", "image/png");

      response.write(IMG_BYTES);

      response.finish();

    });

  }

}