xpcom/glue/nsProxyRelease.cpp

   1 /* vim:set ts=4 sw=4 sts=4 et cin: */
   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.
  16  *
  17  * The Initial Developer of the Original Code is
  18  * Netscape Communications Corporation.
  19  * Portions created by the Initial Developer are Copyright (C) 2003
  20  * the Initial Developer. All Rights Reserved.
  21  *
  22  * Contributor(s):
  23  *   Darin Fisher <darin@meer.net>
  24  *
  25  * Alternatively, the contents of this file may be used under the terms of
  26  * either the GNU General Public License Version 2 or later (the "GPL"), or
  27  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  28  * in which case the provisions of the GPL or the LGPL are applicable instead
  29  * of those above. If you wish to allow use of your version of this file only
  30  * under the terms of either the GPL or the LGPL, and not to allow others to
  31  * use your version of this file under the terms of the MPL, indicate your
  32  * decision by deleting the provisions above and replace them with the notice
  33  * and other provisions required by the GPL or the LGPL. If you do not delete
  34  * the provisions above, a recipient may use your version of this file under
  35  * the terms of any one of the MPL, the GPL or the LGPL.
  36  *
  37  * ***** END LICENSE BLOCK ***** */
  38
  39 #include "nsProxyRelease.h"
  40 #include "nsThreadUtils.h"
  41 #include "nsAutoPtr.h"
  42
  43 class nsProxyReleaseEvent : public nsRunnable
  44 {
  45 public:
  46     nsProxyReleaseEvent(nsISupports *doomed)
  47         : mDoomed(doomed) {
  48     }
  49
  50     NS_IMETHOD Run()
  51     {
  52         mDoomed->Release();
  53         return NS_OK;
  54     }
  55
  56 private:
  57     nsISupports *mDoomed;
  58 };
  59
  60 nsresult
  61 NS_ProxyRelease(nsIEventTarget *target, nsISupports *doomed,
  62                 PRBool alwaysProxy)
  63 {
  64     nsresult rv;
  65
  66     if (!target) {
  67         NS_RELEASE(doomed);
  68         return NS_OK;
  69     }
  70
  71     if (!alwaysProxy) {
  72         PRBool onCurrentThread = PR_FALSE;
  73         rv = target->IsOnCurrentThread(&onCurrentThread);
  74         if (NS_SUCCEEDED(rv) && onCurrentThread) {
  75             NS_RELEASE(doomed);
  76             return NS_OK;
  77         }
  78     }
  79
  80     nsRefPtr<nsIRunnable> ev = new nsProxyReleaseEvent(doomed);
  81     if (!ev) {
  82         // we do not release doomed here since it may cause a delete on the
  83         // wrong thread.  better to leak than crash.
  84         return NS_ERROR_OUT_OF_MEMORY;
  85     }
  86
  87     rv = target->Dispatch(ev, NS_DISPATCH_NORMAL);
  88     if (NS_FAILED(rv)) {
  89         NS_WARNING("failed to post proxy release event");
  90         // again, it is better to leak the doomed object than risk crashing as
  91         // a result of deleting it on the wrong thread.
  92     }
  93     return rv;
  94 }