dom/base/GlobalTeardownObserver.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef DOM_BASE_GLOBALTEARDOWNOBSERVER_H_
   8 #define DOM_BASE_GLOBALTEARDOWNOBSERVER_H_
   9
  10 #include "mozilla/Attributes.h"
  11 #include "nsIGlobalObject.h"
  12 #include "nsIScriptGlobalObject.h"
  13
  14 namespace mozilla {
  15
  16 class GlobalTeardownObserver
  17
  18     : public nsISupports,
  19       public LinkedListElement<GlobalTeardownObserver> {
  20  public:
  21   GlobalTeardownObserver();
  22   explicit GlobalTeardownObserver(nsIGlobalObject* aGlobalObject,
  23                                   bool aHasOrHasHadOwnerWindow = false);
  24
  25   nsGlobalWindowInner* GetOwnerWindow() const;
  26   nsIGlobalObject* GetOwnerGlobal() const { return mParentObject; }
  27   bool HasOrHasHadOwnerWindow() const { return mHasOrHasHadOwnerWindow; }
  28
  29   void GetParentObject(nsIScriptGlobalObject** aParentObject) {
  30     if (mParentObject) {
  31       CallQueryInterface(mParentObject, aParentObject);
  32     } else {
  33       *aParentObject = nullptr;
  34     }
  35   }
  36
  37   virtual void DisconnectFromOwner();
  38
  39   // A global permanently becomes invalid when DisconnectEventTargetObjects() is
  40   // called.  Normally this means:
  41   // - For the main thread, when nsGlobalWindowInner::FreeInnerObjects is
  42   //   called.
  43   // - For a worker thread, when clearing the main event queue.  (Which we do
  44   //   slightly later than when the spec notionally calls for it to be done.)
  45   //
  46   // A global may also become temporarily invalid when:
  47   // - For the main thread, if the window is no longer the WindowProxy's current
  48   //   inner window due to being placed in the bfcache.
  49   nsresult CheckCurrentGlobalCorrectness() const;
  50
  51  protected:
  52   virtual ~GlobalTeardownObserver();
  53
  54   void BindToOwner(nsIGlobalObject* aOwner);
  55
  56  private:
  57   // The parent global object.  The global will clear this when
  58   // it is destroyed by calling DisconnectFromOwner().
  59   nsIGlobalObject* MOZ_NON_OWNING_REF mParentObject = nullptr;
  60   // If mParentObject is or has been an inner window, then this is true. It is
  61   // obtained in BindToOwner.
  62   bool mHasOrHasHadOwnerWindow = false;
  63 };
  64
  65 }  // namespace mozilla
  66
  67 #endif