michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef nsLayoutStatics_h__
michael@0: #define nsLayoutStatics_h__
michael@0: 
michael@0: #include "nscore.h"
michael@0: #include "MainThreadUtils.h"
michael@0: #include "nsISupportsImpl.h"
michael@0: #include "nsDebug.h"
michael@0: 
michael@0: // This isn't really a class, it's a namespace for static methods.
michael@0: // Documents and other objects can hold a reference to the layout static
michael@0: // objects so that they last past the xpcom-shutdown notification.
michael@0: 
michael@0: class nsLayoutStatics
michael@0: {
michael@0: public:
michael@0:   // Called by the layout module constructor. This call performs an AddRef()
michael@0:   // internally.
michael@0:   static nsresult Initialize();
michael@0: 
michael@0:   static void AddRef()
michael@0:   {
michael@0:     NS_ASSERTION(NS_IsMainThread(),
michael@0:                  "nsLayoutStatics reference counting must be on main thread");
michael@0: 
michael@0:     NS_ASSERTION(sLayoutStaticRefcnt,
michael@0:                  "nsLayoutStatics already dropped to zero!");
michael@0: 
michael@0:     ++sLayoutStaticRefcnt;
michael@0:     NS_LOG_ADDREF(&sLayoutStaticRefcnt, sLayoutStaticRefcnt,
michael@0:                   "nsLayoutStatics", 1);
michael@0:   }
michael@0:   static void Release()
michael@0:   {
michael@0:     NS_ASSERTION(NS_IsMainThread(),
michael@0:                  "nsLayoutStatics reference counting must be on main thread");
michael@0: 
michael@0:     --sLayoutStaticRefcnt;
michael@0:     NS_LOG_RELEASE(&sLayoutStaticRefcnt, sLayoutStaticRefcnt,
michael@0:                    "nsLayoutStatics");
michael@0: 
michael@0:     if (!sLayoutStaticRefcnt)
michael@0:       Shutdown();
michael@0:   }
michael@0: 
michael@0: private:
michael@0:   // not to be called!
michael@0:   nsLayoutStatics();
michael@0: 
michael@0:   static void Shutdown();
michael@0: 
michael@0:   static nsrefcnt sLayoutStaticRefcnt;
michael@0: };
michael@0: 
michael@0: class nsLayoutStaticsRef
michael@0: {
michael@0: public:
michael@0:   nsLayoutStaticsRef()
michael@0:   {
michael@0:     nsLayoutStatics::AddRef();
michael@0:   }
michael@0:   ~nsLayoutStaticsRef()
michael@0:   {
michael@0:     nsLayoutStatics::Release();
michael@0:   }
michael@0: };
michael@0: 
michael@0: #endif // nsLayoutStatics_h__