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 "mozilla/dom/EventTarget.h"
  12 #include "mozilla/RefPtr.h"
  13 #include "nsCycleCollectionParticipant.h"
  14 #include "nsID.h"
  15 #include "nsIGlobalObject.h"
  16 #include "nsIScriptGlobalObject.h"
  17 #include "nsISupports.h"
  18 #include "nsISupportsUtils.h"
  19 #include "nsPIDOMWindow.h"
  20
  21 #define NS_GLOBALTEARDOWNOBSERVER_IID                \
  22   {                                                  \
  23     0xc31fddb9, 0xec49, 0x4f24, {                    \
  24       0x90, 0x16, 0xb5, 0x2b, 0x26, 0x6c, 0xb6, 0x29 \
  25     }                                                \
  26   }
  27
  28 namespace mozilla {
  29
  30 class GlobalTeardownObserver
  31     : public nsISupports,
  32       public LinkedListElement<GlobalTeardownObserver> {
  33  public:
  34   NS_DECLARE_STATIC_IID_ACCESSOR(NS_GLOBALTEARDOWNOBSERVER_IID)
  35
  36   GlobalTeardownObserver();
  37   explicit GlobalTeardownObserver(nsIGlobalObject* aGlobalObject,
  38                                   bool aHasOrHasHadOwnerWindow = false);
  39
  40   nsPIDOMWindowInner* GetOwner() const { return mOwnerWindow; }
  41   nsIGlobalObject* GetOwnerGlobal() const { return mParentObject; }
  42   bool HasOrHasHadOwner() { return mHasOrHasHadOwnerWindow; }
  43
  44   void GetParentObject(nsIScriptGlobalObject** aParentObject) {
  45     if (mParentObject) {
  46       CallQueryInterface(mParentObject, aParentObject);
  47     } else {
  48       *aParentObject = nullptr;
  49     }
  50   }
  51
  52   virtual void DisconnectFromOwner();
  53
  54   // A global permanently becomes invalid when DisconnectEventTargetObjects() is
  55   // called.  Normally this means:
  56   // - For the main thread, when nsGlobalWindowInner::FreeInnerObjects is
  57   //   called.
  58   // - For a worker thread, when clearing the main event queue.  (Which we do
  59   //   slightly later than when the spec notionally calls for it to be done.)
  60   //
  61   // A global may also become temporarily invalid when:
  62   // - For the main thread, if the window is no longer the WindowProxy's current
  63   //   inner window due to being placed in the bfcache.
  64   nsresult CheckCurrentGlobalCorrectness() const;
  65
  66  protected:
  67   virtual ~GlobalTeardownObserver();
  68
  69   void BindToOwner(nsIGlobalObject* aOwner);
  70
  71  private:
  72   // The parent global object.  The global will clear this when
  73   // it is destroyed by calling DisconnectFromOwner().
  74   nsIGlobalObject* MOZ_NON_OWNING_REF mParentObject = nullptr;
  75   // mParentObject pre QI-ed and cached (inner window)
  76   // (it is needed for off main thread access)
  77   // It is obtained in BindToOwner and reset in DisconnectFromOwner.
  78   nsPIDOMWindowInner* MOZ_NON_OWNING_REF mOwnerWindow = nullptr;
  79   bool mHasOrHasHadOwnerWindow = false;
  80 };
  81
  82 NS_DEFINE_STATIC_IID_ACCESSOR(GlobalTeardownObserver,
  83                               NS_GLOBALTEARDOWNOBSERVER_IID)
  84
  85 }  // namespace mozilla
  86
  87 #endif