/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
#include "nsISupports.idl"

/* nsINativeAppSupport
 *
 * This "pseudo" (in the XPCOM sense) interface provides for
 * platform-specific general application support:
 *  o It manages the details of the simple DDE communication 
 *    supported on the Win32 platform (it is the addition of this 
 *    item that prompted the creation of this interface.
 *
 * Due to the nature of the beast, this interface is not a full-blown
 * XPCOM component.  The primary reason is that objects that implement
 * this interface generally must be operational *before* XPCOM (or any
 * of the rest of Mozilla) are initialized.  As a result, this 
 * interface is instantiated by somewhat unconventional means.
 *
 * To create the implementor of this interface, you call the function
 * NS_CreateNativeAppSupport.  This is done in the startup code
 * in nsAppRunner.cpp
 *
 * The interface provides these functions:
 *  start - You call this to inform the native app support that the  
 *          application is starting.  In addition, it serves as a
 *          query as to whether the application should continue to
 *          run.
 *
 *          If the returned boolean result is PR_FALSE, then the
 *          application should exit without further processing.  In
 *          such cases, the returned nsresult indicates whether the
 *          reason to exit is due to an error or not.
 *
 *          Win32 Note: In the case of starting a second instance
 *                      of this executable, this function will return
 *                      PR_FALSE and nsresult==NS_OK.  This means that
 *                      the command line arguments have been
 *                      successfully passed to the instance of the
 *                      application acting as a DDE server.
 *
 *  stop - You call this to inform the native app support that the
 *         application *wishes* to terminate.  If the returned boolean
 *         value is PR_FALSE, then the application should continue
 *         (as if there were still additional top-level windows open).
 *         
 *         Win32 Note: If this is the instance of the application
 *                     acting as the DDE server, and there are current
 *                     DDE conversations active with other instances
 *                     acting as DDE clients, then this function will
 *                     return PR_FALSE.
 * 
 *  quit - Like Stop, but this method *forces* termination (or more 
 *         precisely, indicates that the application is about to be
 *         terminated regardless of what a call to Stop might have
 *         returned.
 *
 *         This method is intended to be called when the user selects
 *         the "Quit" option (close all windows and exit).
 *
 *         Win32 Note: Stop is problematic in the case of "Quit" (close
 *                     all windows and exit the application) because
 *                     either we don't Quit or (potentially) we lose
 *                     requests coming from other instances of the
 *                     application.  The strategy is to give preference
 *                     to the user's explicit Quit request.  In the
 *                     unlikely event that a request is pending from
 *                     another instance of the application, then such
 *                     requests are essentially ignored.  This is
 *                     roughly equivalent to handling that request by
 *                     opening a new window, followed by immediately
 *                     closing it.  Since this is the same as if the
 *                     request came in immediately before the Quit
 *                     call (versus immediately after it), no harm.
 *
 *                     There is an exposure here: Upon return from this
 *                     function, any DDE connect request (for Mozilla)
 *                     will fail and other instances of the application
 *                     will start up as a DDE server.  In that case,
 *                     those instances may do things that conflict with
 *                     the subsequent shutting down of the instance that
 *                     is quitting.  For this reason, the call to Quit
 *                     should be deferred as long as possible.
 *
 *  onLastWindowClosing -  Called when the last window is closed. Used as a
 *                         "soft" shutdown, passwords are flushed.
 */

interface nsIXULWindow;

[scriptable, uuid(5fdf8480-1f98-11d4-8077-00600811a9c3)]
interface nsINativeAppSupport : nsISupports {
    // Startup/shutdown.
    boolean start();
    void    enable();
    boolean stop();
    void    quit();

    void onLastWindowClosing();
    void ReOpen();
};
