LCOV - code coverage report
Current view: directory - objdir/dist/include - nsISupportsUtils.h (source / functions) Found Hit Coverage
Test: app.info Lines: 8 8 100.0 %
Date: 2012-06-02 Functions: 530 143 27.0 %

       1                 : /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
       2                 : /* ***** BEGIN LICENSE BLOCK *****
       3                 :  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
       4                 :  *
       5                 :  * The contents of this file are subject to the Mozilla Public License Version
       6                 :  * 1.1 (the "License"); you may not use this file except in compliance with
       7                 :  * the License. You may obtain a copy of the License at
       8                 :  * http://www.mozilla.org/MPL/
       9                 :  *
      10                 :  * Software distributed under the License is distributed on an "AS IS" basis,
      11                 :  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
      12                 :  * for the specific language governing rights and limitations under the
      13                 :  * License.
      14                 :  *
      15                 :  * The Original Code is mozilla.org code.
      16                 :  *
      17                 :  * The Initial Developer of the Original Code is
      18                 :  * Netscape Communications Corporation.
      19                 :  * Portions created by the Initial Developer are Copyright (C) 1998
      20                 :  * the Initial Developer. All Rights Reserved.
      21                 :  *
      22                 :  * Contributor(s):
      23                 :  *   Pierre Phaneuf <pp@ludusdesign.com>
      24                 :  *   Scott Collins <scc@ScottCollins.net>
      25                 :  *   Dan Mosedale <dmose@mozilla.org>
      26                 :  *
      27                 :  * Alternatively, the contents of this file may be used under the terms of
      28                 :  * either of the GNU General Public License Version 2 or later (the "GPL"),
      29                 :  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
      30                 :  * in which case the provisions of the GPL or the LGPL are applicable instead
      31                 :  * of those above. If you wish to allow use of your version of this file only
      32                 :  * under the terms of either the GPL or the LGPL, and not to allow others to
      33                 :  * use your version of this file under the terms of the MPL, indicate your
      34                 :  * decision by deleting the provisions above and replace them with the notice
      35                 :  * and other provisions required by the GPL or the LGPL. If you do not delete
      36                 :  * the provisions above, a recipient may use your version of this file under
      37                 :  * the terms of any one of the MPL, the GPL or the LGPL.
      38                 :  *
      39                 :  * ***** END LICENSE BLOCK ***** */
      40                 : 
      41                 : #ifndef nsISupportsUtils_h__
      42                 : #define nsISupportsUtils_h__
      43                 : 
      44                 : #ifndef nscore_h___
      45                 : #include "nscore.h"
      46                 : #endif
      47                 : 
      48                 : #ifndef nsISupportsBase_h__
      49                 : #include "nsISupportsBase.h"
      50                 : #endif
      51                 : 
      52                 : #ifndef nsError_h__
      53                 : #include "nsError.h"
      54                 : #endif
      55                 : 
      56                 : #ifndef nsDebug_h___
      57                 : #include "nsDebug.h"
      58                 : #endif
      59                 : 
      60                 : #ifndef nsISupportsImpl_h__
      61                 : #include "nsISupportsImpl.h"
      62                 : #endif
      63                 : 
      64                 : /**
      65                 :  * Macro for adding a reference to an interface.
      66                 :  * @param _ptr The interface pointer.
      67                 :  */
      68                 : #define NS_ADDREF(_ptr) \
      69                 :   (_ptr)->AddRef()
      70                 : 
      71                 : /**
      72                 :  * Macro for adding a reference to this. This macro should be used
      73                 :  * because NS_ADDREF (when tracing) may require an ambiguous cast
      74                 :  * from the pointers primary type to nsISupports. This macro sidesteps
      75                 :  * that entire problem.
      76                 :  */
      77                 : #define NS_ADDREF_THIS() \
      78                 :   AddRef()
      79                 : 
      80                 : 
      81                 : extern "C++" {
      82                 : // ...because some one is accidentally including this file inside
      83                 : // an |extern "C"|
      84                 : 
      85                 : 
      86                 : // Making this a |inline| |template| allows |expr| to be evaluated only once,
      87                 : // yet still denies you the ability to |AddRef()| an |nsCOMPtr|.
      88                 : template <class T>
      89                 : inline
      90                 : void
      91         4731314 : ns_if_addref( T expr )
      92                 : {
      93         4731314 :     if (expr) {
      94         2942755 :         expr->AddRef();
      95                 :     }
      96         4731315 : }
      97                 : 
      98                 : } /* extern "C++" */
      99                 : 
     100                 : /**
     101                 :  * Macro for adding a reference to an interface that checks for NULL.
     102                 :  * @param _expr The interface pointer.
     103                 :  */
     104                 : #define NS_IF_ADDREF(_expr) ns_if_addref(_expr)
     105                 : 
     106                 : /*
     107                 :  * Given these declarations, it explicitly OK and efficient to end a `getter' with:
     108                 :  *
     109                 :  *    NS_IF_ADDREF(*result = mThing);
     110                 :  *
     111                 :  * even if |mThing| is an |nsCOMPtr|.  If |mThing| is an |nsCOMPtr|, however, it is still
     112                 :  * _illegal_ to say |NS_IF_ADDREF(mThing)|.
     113                 :  */
     114                 : 
     115                 : /**
     116                 :  * Macro for releasing a reference to an interface.
     117                 :  * @param _ptr The interface pointer.
     118                 :  */
     119                 : #define NS_RELEASE(_ptr)                                                      \
     120                 :   PR_BEGIN_MACRO                                                              \
     121                 :     (_ptr)->Release();                                                        \
     122                 :     (_ptr) = 0;                                                               \
     123                 :   PR_END_MACRO
     124                 : 
     125                 : /**
     126                 :  * Macro for releasing a reference to an interface.
     127                 :  * @param _ptr The interface pointer.
     128                 :  */
     129                 : #define NS_RELEASE_THIS() \
     130                 :     Release()
     131                 : 
     132                 : /**
     133                 :  * Macro for releasing a reference to an interface, except that this
     134                 :  * macro preserves the return value from the underlying Release call.
     135                 :  * The interface pointer argument will only be NULLed if the reference count
     136                 :  * goes to zero.
     137                 :  *
     138                 :  * @param _ptr The interface pointer.
     139                 :  */
     140                 : #define NS_RELEASE2(_ptr,_rv)                                                 \
     141                 :   PR_BEGIN_MACRO                                                              \
     142                 :     _rv = (_ptr)->Release();                                                  \
     143                 :     if (0 == (_rv)) (_ptr) = 0;                                               \
     144                 :   PR_END_MACRO
     145                 : 
     146                 : /**
     147                 :  * Macro for releasing a reference to an interface that checks for NULL;
     148                 :  * @param _ptr The interface pointer.
     149                 :  */
     150                 : #define NS_IF_RELEASE(_ptr)                                                   \
     151                 :   PR_BEGIN_MACRO                                                              \
     152                 :     if (_ptr) {                                                               \
     153                 :       (_ptr)->Release();                                                      \
     154                 :       (_ptr) = 0;                                                             \
     155                 :     }                                                                         \
     156                 :   PR_END_MACRO
     157                 : 
     158                 : /*
     159                 :  * Often you have to cast an implementation pointer, e.g., |this|, to an
     160                 :  * |nsISupports*|, but because you have multiple inheritance, a simple cast
     161                 :  * is ambiguous.  One could simply say, e.g., (given a base |nsIBase|),
     162                 :  * |static_cast<nsIBase*>(this)|; but that disguises the fact that what
     163                 :  * you are really doing is disambiguating the |nsISupports|.  You could make
     164                 :  * that more obvious with a double cast, e.g., |static_cast<nsISupports*>
     165                 :                                                            (* static_cast<nsIBase*>(this))|, but that is bulky and harder to read...
     166                 :  *
     167                 :  * The following macro is clean, short, and obvious.  In the example above,
     168                 :  * you would use it like this: |NS_ISUPPORTS_CAST(nsIBase*, this)|.
     169                 :  */
     170                 : 
     171                 : #define NS_ISUPPORTS_CAST(__unambiguousBase, __expr) \
     172                 :   static_cast<nsISupports*>(static_cast<__unambiguousBase>(__expr))
     173                 : 
     174                 : // a type-safe shortcut for calling the |QueryInterface()| member function
     175                 : template <class T, class DestinationType>
     176                 : inline
     177                 : nsresult
     178         7074146 : CallQueryInterface( T* aSource, DestinationType** aDestination )
     179                 : {
     180         7074146 :     NS_PRECONDITION(aSource, "null parameter");
     181         7074146 :     NS_PRECONDITION(aDestination, "null parameter");
     182                 :     
     183                 :     return aSource->QueryInterface(NS_GET_TEMPLATE_IID(DestinationType),
     184         7074146 :                                    reinterpret_cast<void**>(aDestination));
     185                 : }
     186                 : 
     187                 : #endif /* __nsISupportsUtils_h */

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