gecko-dev/browser/extensions/screenshots/background/communication.js

/* globals catcher, log */

"use strict";

this.communication = (function() {
  const exports = {};

  const registeredFunctions = {};

  exports.onMessage = catcher.watchFunction((req, sender, sendResponse) => {
    if (!(req.funcName in registeredFunctions)) {
      log.error(`Received unknown internal message type ${req.funcName}`);
      sendResponse({type: "error", name: "Unknown message type"});
      return;
    }
    if (!Array.isArray(req.args)) {
      log.error("Received message with no .args list");
      sendResponse({type: "error", name: "No .args"});
      return;
    }
    const func = registeredFunctions[req.funcName];
    let result;
    try {
      req.args.unshift(sender);
      result = func.apply(null, req.args);
    } catch (e) {
      log.error(`Error in ${req.funcName}:`, e, e.stack);
      // FIXME: should consider using makeError from catcher here:
      sendResponse({type: "error", message: e + "", errorCode: e.errorCode, popupMessage: e.popupMessage});
      return;
    }
    if (result && result.then) {
      result.then((concreteResult) => {
        sendResponse({type: "success", value: concreteResult});
      }).catch((errorResult) => {
        log.error(`Promise error in ${req.funcName}:`, errorResult, errorResult && errorResult.stack);
        sendResponse({type: "error", message: errorResult + "", errorCode: errorResult.errorCode, popupMessage: errorResult.popupMessage});
      });
      return;
    }
    sendResponse({type: "success", value: result});
  });

  exports.register = function(name, func) {
    registeredFunctions[name] = func;
  };

  return exports;
})();