fune/browser/components/extensions/ext-devtools-inspectedWindow.js

/* -*- Mode: indent-tabs-mode: nil; js-indent-level: 2 -*- */
/* vim: set sts=2 sw=2 et tw=80: */
"use strict";

/* global getDevToolsTargetForContext */

Cu.import("resource://gre/modules/ExtensionUtils.jsm");

const {
  SpreadArgs,
} = ExtensionUtils;

extensions.registerSchemaAPI("devtools.inspectedWindow", "devtools_parent", context => {
  const {
    WebExtensionInspectedWindowFront,
  } = require("devtools/shared/fronts/webextension-inspected-window");

  // Lazily retrieve and store an inspectedWindow actor front per child context.
  let waitForInspectedWindowFront;
  async function getInspectedWindowFront() {
    // If there is not yet a front instance, then a lazily cloned target for the context is
    // retrieved using the DevtoolsParentContextsManager helper (which is an asynchronous operation,
    // because the first time that the target has been cloned, it is not ready to be used to create
    // the front instance until it is connected to the remote debugger successfully).
    const clonedTarget = await getDevToolsTargetForContext(context);
    return new WebExtensionInspectedWindowFront(clonedTarget.client, clonedTarget.form);
  }

  // TODO(rpl): retrive a more detailed callerInfo object, like the filename and
  // lineNumber of the actual extension called, in the child process.
  const callerInfo = {
    addonId: context.extension.id,
    url: context.extension.baseURI.spec,
  };

  return {
    devtools: {
      inspectedWindow: {
        async eval(expression, options) {
          if (!waitForInspectedWindowFront) {
            waitForInspectedWindowFront = getInspectedWindowFront();
          }

          const front = await waitForInspectedWindowFront;
          return front.eval(callerInfo, expression, options || {}).then(evalResult => {
            // TODO(rpl): check for additional undocumented behaviors on chrome
            // (e.g. if we should also print error to the console or set lastError?).
            return new SpreadArgs([evalResult.value, evalResult.exceptionInfo]);
          });
        },
      },
    },
  };
});