layout/build/nsLayoutStatics.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 nsLayoutStatics_h__
   8 #define nsLayoutStatics_h__
   9
  10 #include "nscore.h"
  11 #include "MainThreadUtils.h"
  12 #include "nsISupportsImpl.h"
  13 #include "nsDebug.h"
  14
  15 // This isn't really a class, it's a namespace for static methods.
  16 // Documents and other objects can hold a reference to the layout static
  17 // objects so that they last past the xpcom-shutdown notification.
  18
  19 class nsLayoutStatics {
  20  public:
  21   // Called by the layout module constructor. This call performs an AddRef()
  22   // internally.
  23   static nsresult Initialize();
  24
  25   static void AddRef() {
  26     NS_ASSERTION(NS_IsMainThread(),
  27                  "nsLayoutStatics reference counting must be on main thread");
  28
  29     NS_ASSERTION(sLayoutStaticRefcnt,
  30                  "nsLayoutStatics already dropped to zero!");
  31
  32     ++sLayoutStaticRefcnt;
  33     NS_LOG_ADDREF(&sLayoutStaticRefcnt, sLayoutStaticRefcnt, "nsLayoutStatics",
  34                   1);
  35   }
  36   static void Release() {
  37     NS_ASSERTION(NS_IsMainThread(),
  38                  "nsLayoutStatics reference counting must be on main thread");
  39
  40     --sLayoutStaticRefcnt;
  41     NS_LOG_RELEASE(&sLayoutStaticRefcnt, sLayoutStaticRefcnt,
  42                    "nsLayoutStatics");
  43
  44     if (!sLayoutStaticRefcnt) Shutdown();
  45   }
  46
  47  private:
  48   // not to be called!
  49   nsLayoutStatics();
  50
  51   static void Shutdown();
  52
  53   static nsrefcnt sLayoutStaticRefcnt;
  54 };
  55
  56 #endif  // nsLayoutStatics_h__