Version 1.8 of gecko-sdk. Downloaded from here:...

gecko-sdk/include/nsIWeakReferenceUtils.h

+/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* ***** 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 mozilla.org code.
+ *
+ * The Initial Developer of the Original Code is
+ * Netscape Communications Corporation.
+ * Portions created by the Initial Developer are Copyright (C) 1998
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *   Scott Collins <scc@mozilla.org> (Original Author)
+ *
+ * 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 nsIWeakReferenceUtils_h__
+#define nsIWeakReferenceUtils_h__
+
+#ifndef nsCOMPtr_h__
+#include "nsCOMPtr.h"
+#endif
+
+typedef nsCOMPtr<nsIWeakReference> nsWeakPtr;
+
+/**
+ *
+ */
+
+// a type-safe shortcut for calling the |QueryReferent()| member function
+// T must inherit from nsIWeakReference, but the cast may be ambiguous.
+template <class T, class DestinationType>
+inline
+nsresult
+CallQueryReferent( T* aSource, DestinationType** aDestination )
+  {
+    NS_PRECONDITION(aSource, "null parameter");
+    NS_PRECONDITION(aDestination, "null parameter");
+
+    return aSource->QueryReferent(NS_GET_IID(DestinationType),
+                                  NS_REINTERPRET_CAST(void**, aDestination));
+  }
+
+
+class NS_COM_GLUE nsQueryReferent : public nsCOMPtr_helper
+  {
+    public:
+      nsQueryReferent( nsIWeakReference* aWeakPtr, nsresult* error )
+          : mWeakPtr(aWeakPtr),
+            mErrorPtr(error)
+        {
+          // nothing else to do here
+        }
+
+      virtual nsresult NS_FASTCALL operator()( const nsIID& aIID, void** ) const;
+
+    private:
+      nsIWeakReference*  mWeakPtr;
+      nsresult*          mErrorPtr;
+  };
+
+inline
+const nsQueryReferent
+do_QueryReferent( nsIWeakReference* aRawPtr, nsresult* error = 0 )
+  {
+    return nsQueryReferent(aRawPtr, error);
+  }
+
+
+  /**
+   * Deprecated, use |do_GetWeakReference| instead.
+   */
+extern NS_COM_GLUE
+nsIWeakReference*
+NS_GetWeakReference( nsISupports* , nsresult* aResult=0 );
+
+  /**
+   * |do_GetWeakReference| is a convenience function that bundles up all the work needed
+   * to get a weak reference to an arbitrary object, i.e., the |QueryInterface|, test, and
+   * call through to |GetWeakReference|, and put it into your |nsCOMPtr|.
+   * It is specifically designed to cooperate with |nsCOMPtr| (or |nsWeakPtr|) like so:
+   * |nsWeakPtr myWeakPtr = do_GetWeakReference(aPtr);|.
+   */
+inline
+already_AddRefed<nsIWeakReference>
+do_GetWeakReference( nsISupports* aRawPtr, nsresult* error = 0 )
+  {
+    return NS_GetWeakReference(aRawPtr, error);
+  }
+
+inline
+void
+do_GetWeakReference( nsIWeakReference* aRawPtr, nsresult* error = 0 )
+  {
+    // This signature exists soley to _stop_ you from doing a bad thing.
+    //  Saying |do_GetWeakReference()| on a weak reference itself,
+    //  is very likely to be a programmer error.
+  }
+
+template <class T>
+inline
+void
+do_GetWeakReference( already_AddRefed<T>& )
+  {
+    // This signature exists soley to _stop_ you from doing the bad thing.
+    //  Saying |do_GetWeakReference()| on a pointer that is not otherwise owned by
+    //  someone else is an automatic leak.  See <http://bugzilla.mozilla.org/show_bug.cgi?id=8221>.
+  }
+
+template <class T>
+inline
+void
+do_GetWeakReference( already_AddRefed<T>&, nsresult* )
+  {
+    // This signature exists soley to _stop_ you from doing the bad thing.
+    //  Saying |do_GetWeakReference()| on a pointer that is not otherwise owned by
+    //  someone else is an automatic leak.  See <http://bugzilla.mozilla.org/show_bug.cgi?id=8221>.
+  }
+
+#endif