Initial community commit

Src/nprt_plugin/gecko/1.8/win/include/nsWeakReference.h

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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is the Mozilla browser.
+ *
+ * The Initial Developer of the Original Code is
+ * Netscape Communications, Inc.
+ * Portions created by the Initial Developer are Copyright (C) 1999
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *   Scott Collins <scc@netscape.com>
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either of the GNU General Public License Version 2 or later (the "GPL"),
+ * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+#ifndef nsWeakReference_h__
+#define nsWeakReference_h__
+
+// nsWeakReference.h
+
+#include "nsIWeakReference.h"
+#include "nsIWeakReferenceUtils.h"
+
+class nsWeakReference;
+
+#undef  IMETHOD_VISIBILITY
+#define IMETHOD_VISIBILITY NS_VISIBILITY_DEFAULT
+
+class NS_COM_GLUE nsSupportsWeakReference : public nsISupportsWeakReference
+  {
+    public:
+      nsSupportsWeakReference()
+          : mProxy(0)
+        {
+          // nothing else to do here
+        }
+
+      NS_DECL_NSISUPPORTSWEAKREFERENCE
+
+    protected:
+      inline ~nsSupportsWeakReference();
+
+    private:
+      friend class nsWeakReference;
+
+      void
+      NoticeProxyDestruction()
+          // ...called (only) by an |nsWeakReference| from _its_ dtor.
+        {
+          mProxy = 0;
+        }
+
+      nsWeakReference* mProxy;
+
+		protected:
+
+			inline void ClearWeakReferences();
+			PRBool HasWeakReferences() const {return mProxy != 0;}
+  };
+
+#undef  IMETHOD_VISIBILITY
+#define IMETHOD_VISIBILITY NS_VISIBILITY_HIDDEN
+
+class NS_COM_GLUE nsWeakReference : public nsIWeakReference
+  {
+    public:
+    // nsISupports...
+      NS_DECL_ISUPPORTS
+
+    // nsIWeakReference...
+      NS_DECL_NSIWEAKREFERENCE
+
+    private:
+      friend class nsSupportsWeakReference;
+
+      nsWeakReference( nsSupportsWeakReference* referent )
+          : mReferent(referent)
+          // ...I can only be constructed by an |nsSupportsWeakReference|
+        {
+          // nothing else to do here
+        }
+
+      ~nsWeakReference()
+           // ...I will only be destroyed by calling |delete| myself.
+        {
+          if ( mReferent )
+            mReferent->NoticeProxyDestruction();
+        }
+
+      void
+      NoticeReferentDestruction()
+          // ...called (only) by an |nsSupportsWeakReference| from _its_ dtor.
+        {
+          mReferent = 0;
+        }
+
+      nsSupportsWeakReference*  mReferent;
+  };
+
+inline
+void
+nsSupportsWeakReference::ClearWeakReferences()
+		/*
+			Usually being called from |nsSupportsWeakReference::~nsSupportsWeakReference|
+			will be good enough, but you may have a case where you need to call disconnect
+			your weak references in an outer destructor (to prevent some client holding a
+			weak reference from re-entering your destructor).
+		*/
+	{
+		if ( mProxy )
+			{
+				mProxy->NoticeReferentDestruction();
+				mProxy = 0;
+			}
+	}
+
+inline
+nsSupportsWeakReference::~nsSupportsWeakReference()
+  {
+  	ClearWeakReferences();
+  }
+
+#endif