import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

devtools/server/actors/utils/make-debugger.js

@@ -0,0 +1,101 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2; js-indent-level: 2 -*- */
+/* vim: set ft=javascript ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const EventEmitter = require("devtools/shared/event-emitter");
+const Debugger = require("Debugger");
+
+const { reportException } = require("devtools/shared/DevToolsUtils");
+
+/**
+ * Multiple actors that use a |Debugger| instance come in a few versions, each
+ * with a different set of debuggees. One version for content tabs (globals
+ * within a tab), one version for chrome debugging (all globals), and sometimes
+ * a third version for addon debugging (chrome globals the addon is loaded in
+ * and content globals the addon injects scripts into). The |makeDebugger|
+ * function helps us avoid repeating the logic for finding and maintaining the
+ * correct set of globals for a given |Debugger| instance across each version of
+ * all of our actors.
+ *
+ * The |makeDebugger| function expects a single object parameter with the
+ * following properties:
+ *
+ * @param Function findDebuggees
+ *        Called with one argument: a |Debugger| instance. This function should
+ *        return an iterable of globals to be added to the |Debugger|
+ *        instance. The globals may be wrapped in a |Debugger.Object|, or
+ *        unwrapped.
+ *
+ * @param Function shouldAddNewGlobalAsDebuggee
+ *        Called with one argument: a |Debugger.Object| wrapping a global
+ *        object. This function must return |true| if the global object should
+ *        be added as debuggee, and |false| otherwise.
+ *
+ * @returns Debugger
+ *          Returns a |Debugger| instance that can manage its set of debuggee
+ *          globals itself and is decorated with the |EventEmitter| class.
+ *
+ *          Events emitted by the returned |Debugger| instance:
+ *
+ *            - "newGlobal": Emitted when a new global has been added as a
+ *               debuggee. Passes the |Debugger.Object| wrapping the new
+ *               debuggee global to listeners.
+ *
+ *          Existing |Debugger| properties set on the returned |Debugger|
+ *          instance:
+ *
+ *            - onNewGlobalObject: The |Debugger| will automatically add new
+ *              globals as debuggees if calling |shouldAddNewGlobalAsDebuggee|
+ *              with the global returns true.
+ *
+ *            - uncaughtExceptionHook: The |Debugger| already has an error
+ *              reporter attached to |uncaughtExceptionHook|, so if any
+ *              |Debugger| hooks fail, the error will be reported.
+ *
+ *          New properties set on the returned |Debugger| instance:
+ *
+ *            - addDebuggees: A function which takes no arguments. It adds all
+ *              current globals that should be debuggees (as determined by
+ *              |findDebuggees|) to the |Debugger| instance.
+ */
+module.exports = function makeDebugger({ findDebuggees, shouldAddNewGlobalAsDebuggee }) {
+  const dbg = new Debugger();
+  EventEmitter.decorate(dbg);
+
+  dbg.allowUnobservedAsmJS = true;
+  dbg.uncaughtExceptionHook = reportDebuggerHookException;
+
+  dbg.onNewGlobalObject = function (global) {
+    if (shouldAddNewGlobalAsDebuggee(global)) {
+      safeAddDebuggee(this, global);
+    }
+  };
+
+  dbg.addDebuggees = function () {
+    for (let global of findDebuggees(this)) {
+      safeAddDebuggee(this, global);
+    }
+  };
+
+  return dbg;
+};
+
+const reportDebuggerHookException = e => reportException("Debugger Hook", e);
+
+/**
+ * Add |global| as a debuggee to |dbg|, handling error cases.
+ */
+function safeAddDebuggee(dbg, global) {
+  try {
+    let wrappedGlobal = dbg.addDebuggee(global);
+    if (wrappedGlobal) {
+      dbg.emit("newGlobal", wrappedGlobal);
+    }
+  } catch (e) {
+    // Ignoring attempt to add the debugger's compartment as a debuggee.
+  }
+}