widget/nsAppShellSingleton.h

   1 /* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef nsAppShellSingleton_h__
   7 #define nsAppShellSingleton_h__
   8
   9 /**
  10  * This file is designed to be included into the file that provides the
  11  * nsIModule implementation for a particular widget toolkit.
  12  *
  13  * The following functions are defined:
  14  *   nsAppShellInit
  15  *   nsAppShellShutdown
  16  *   nsAppShellConstructor
  17  *
  18  * The nsAppShellInit function is designed to be used as a module constructor.
  19  * If you already have a module constructor, then call nsAppShellInit from your
  20  * module constructor.
  21  *
  22  * The nsAppShellShutdown function is designed to be used as a module
  23  * destructor.  If you already have a module destructor, then call
  24  * nsAppShellShutdown from your module destructor.
  25  *
  26  * The nsAppShellConstructor function is designed to be used as a factory
  27  * method for the nsAppShell class.
  28  */
  29
  30 #include "nsXULAppAPI.h"
  31
  32 static nsIAppShell* sAppShell;
  33
  34 static nsresult nsAppShellInit() {
  35   NS_ASSERTION(!sAppShell, "already initialized");
  36
  37   sAppShell = new nsAppShell();
  38   if (!sAppShell) return NS_ERROR_OUT_OF_MEMORY;
  39   NS_ADDREF(sAppShell);
  40
  41   nsresult rv = static_cast<nsAppShell*>(sAppShell)->Init();
  42   // If we somehow failed to initialize the appshell, it's extremely likely
  43   // that we are sufficiently hosed that continuing on is just going to lead
  44   // to bad things later.  By crashing early here, the crash report will
  45   // potentially contain a little more insight into what's going wrong than
  46   // if we waited for a crash further down the line.  See also bug 1545381.
  47   MOZ_RELEASE_ASSERT(NS_SUCCEEDED(rv));
  48
  49   return NS_OK;
  50 }
  51
  52 static void nsAppShellShutdown() { NS_RELEASE(sAppShell); }
  53
  54 nsresult nsAppShellConstructor(nsISupports* outer, const nsIID& iid,
  55                                void** result) {
  56   NS_ENSURE_TRUE(!outer, NS_ERROR_NO_AGGREGATION);
  57   NS_ENSURE_TRUE(sAppShell, NS_ERROR_NOT_INITIALIZED);
  58
  59   return sAppShell->QueryInterface(iid, result);
  60 }
  61
  62 #endif  // nsAppShellSingleton_h__