added wxApp::Yield()

[wxWidgets.git] / include / wx / app.h

/////////////////////////////////////////////////////////////////////////////
// Name:        app.h
// Purpose:     wxAppBase class and macros used for declaration of wxApp
//              derived class in the user code
// Author:      Julian Smart
// Modified by:
// Created:     01/02/97
// RCS-ID:      $Id$
// Copyright:   (c) Julian Smart and Markus Holzem
// Licence:     wxWindows licence
/////////////////////////////////////////////////////////////////////////////

#ifndef _WX_APP_H_BASE_
#define _WX_APP_H_BASE_

#ifdef __GNUG__
    #pragma interface "appbase.h"
#endif

// ----------------------------------------------------------------------------
// typedefs
// ----------------------------------------------------------------------------

#if (defined(__WXMSW__) && !defined(__WXMICROWIN__)) || defined (__WXPM__)
    class WXDLLEXPORT wxApp;
    typedef wxApp* (*wxAppInitializerFunction)();
#else
    // returning wxApp* won't work with gcc
    #include "wx/object.h"

    typedef wxObject* (*wxAppInitializerFunction)();
#endif

class WXDLLEXPORT wxCmdLineParser;

// ----------------------------------------------------------------------------
// headers we have to include here
// ----------------------------------------------------------------------------

#include "wx/event.h"       // for the base class

#if wxUSE_GUI
    #include "wx/window.h"  // for wxTopLevelWindows
#endif // wxUSE_GUI

#if wxUSE_LOG
    #include "wx/log.h"
#endif

// ----------------------------------------------------------------------------
// constants
// ----------------------------------------------------------------------------

static const int wxPRINT_WINDOWS = 1;
static const int wxPRINT_POSTSCRIPT = 2;

// ----------------------------------------------------------------------------
// the common part of wxApp implementations for all platforms
// ----------------------------------------------------------------------------

class WXDLLEXPORT wxAppBase : public wxEvtHandler
{
public:
    wxAppBase();

    // the virtual functions which may/must be overridden in the derived class
    // -----------------------------------------------------------------------

        // called during the program initialization, returning FALSE from here
        // prevents the program from continuing - it's a good place to create
        // the top level program window and return TRUE.
        //
        // Override: always in GUI application, rarely in console ones.
    virtual bool OnInit();

#if wxUSE_GUI
        // a platform-dependent version of OnInit(): the code here is likely to
        // depend on the toolkit. default version does nothing.
        //
        // Override: rarely.
    virtual bool OnInitGui();
#endif // wxUSE_GUI

        // called to start program execution - the default version just enters
        // the main GUI loop in which events are received and processed until
        // the last window is not deleted (if GetExitOnFrameDelete) or
        // ExitMainLoop() is called. In console mode programs, the execution
        // of the program really starts here
        //
        // Override: rarely in GUI applications, always in console ones.
#if wxUSE_GUI
    virtual int OnRun() { return MainLoop(); };
#else // !GUI
    virtual int OnRun() = 0;
#endif // wxUSE_GUI

        // called after the main loop termination. This is a good place for
        // cleaning up (it may be too late in dtor) and is also useful if you
        // want to return some non-default exit code - this is just the return
        // value of this method.
        //
        // Override: often.
    virtual int OnExit();

        // called when a fatal exception occurs, this function should take care
        // not to do anything which might provoke a nested exception! It may be
        // overridden if you wish to react somehow in non-default way (core
        // dump under Unix, application crash under Windows) to fatal program
        // errors, however extreme care should be taken if you don't want this
        // function to crash.
        //
        // Override: rarely.
    virtual void OnFatalException() { }

    // the worker functions - usually not used directly by the user code
    // -----------------------------------------------------------------

#if wxUSE_GUI
        // execute the main GUI loop, the function returns when the loop ends
    virtual int MainLoop() = 0;

        // exit the main GUI loop during the next iteration (i.e. it does not
        // stop the program immediately!)
    virtual void ExitMainLoop() = 0;

        // returns TRUE if the program is initialized
    virtual bool Initialized() = 0;

        // returns TRUE if there are unprocessed events in the event queue
    virtual bool Pending() = 0;

        // process the first event in the event queue (blocks until an event
        // apperas if there are none currently)
    virtual void Dispatch() = 0;

        // process all currently pending events right now
        //
        // it is an error to call Yield() recursively unless the value of
        // onlyIfNeeded is TRUE
        //
        // WARNING: this function is dangerous as it can lead to unexpected
        //          reentrancies (i.e. when called from an event handler it
        //          may result in calling the same event handler again), use
        //          with _extreme_ care or, better, don't use at all!
    virtual bool Yield(bool onlyIfNeeded = FALSE) = 0;
#endif // wxUSE_GUI

    // application info: name, description, vendor
    // -------------------------------------------

    // NB: all these should be set by the application itself, there are no
    //     reasonable default except for the application name which is taken to
    //     be argv[0]

        // set/get the application name
    wxString GetAppName() const
    {
        if ( !m_appName )
            return m_className;
        else
            return m_appName;
    }
    void SetAppName(const wxString& name) { m_appName = name; }

        // set/get the app class name
    wxString GetClassName() const { return m_className; }
    void SetClassName(const wxString& name) { m_className = name; }

        // set/get the vendor name
    const wxString& GetVendorName() const { return m_vendorName; }
    void SetVendorName(const wxString& name) { m_vendorName = name; }

#if wxUSE_GUI
    // top level window functions
    // --------------------------

        // return TRUE if our app has focus
    virtual bool IsActive() const { return m_isActive; }

        // set the "main" top level window
    void SetTopWindow(wxWindow *win) { m_topWindow = win; }

        // return the "main" top level window (if it hadn't been set previously
        // with SetTopWindow(), will return just some top level window and, if
        // there are none, will return NULL)
    virtual wxWindow *GetTopWindow() const
    {
        if (m_topWindow)
            return m_topWindow;
        else if (wxTopLevelWindows.GetCount() > 0)
            return wxTopLevelWindows.GetFirst()->GetData();
        else
            return (wxWindow *)NULL;
    }

        // control the exit behaviour: by default, the program will exit the
        // main loop (and so, usually, terminate) when the last top-level
        // program window is deleted. Beware that if you disabel this (with
        // SetExitOnFrameDelete(FALSE)), you'll have to call ExitMainLoop()
        // explicitly from somewhere.
    void SetExitOnFrameDelete(bool flag) { m_exitOnFrameDelete = flag; }
    bool GetExitOnFrameDelete() const { return m_exitOnFrameDelete; }

#endif // wxUSE_GUI

    // cmd line parsing stuff
    // ----------------------

    // all of these methods may be overridden in the derived class to
    // customize the command line parsing (by default only a few standard
    // options are handled)
    //
    // you also need to call wxApp::OnInit() from YourApp::OnInit() for all
    // this to work

#if wxUSE_CMDLINE_PARSER
    // this one is called from OnInit() to add all supported options
    // to the given parser
    virtual void OnInitCmdLine(wxCmdLineParser& parser);

    // called after successfully parsing the command line, return TRUE
    // to continue and FALSE to exit
    virtual bool OnCmdLineParsed(wxCmdLineParser& parser);

    // called if "--help" option was specified, return TRUE to continue
    // and FALSE to exit
    virtual bool OnCmdLineHelp(wxCmdLineParser& parser);

    // called if incorrect command line options were given, return
    // FALSE to abort and TRUE to continue
    virtual bool OnCmdLineError(wxCmdLineParser& parser);
#endif // wxUSE_CMDLINE_PARSER

    // miscellaneous customization functions
    // -------------------------------------

#if wxUSE_LOG
        // override this function to create default log target of arbitrary
        // user-defined class (default implementation creates a wxLogGui
        // object) - this log object is used by default by all wxLogXXX()
        // functions.
    virtual wxLog *CreateLogTarget()
        #if wxUSE_GUI && wxUSE_LOGGUI && !defined(__WXMICROWIN__)
            { return new wxLogGui; }
        #else // !GUI
            { return new wxLogStderr; }
        #endif // wxUSE_GUI
#endif // wxUSE_LOG

#if wxUSE_GUI
        // get the standard icon used by wxWin dialogs - this allows the user
        // to customize the standard dialogs. The 'which' parameter is one of
        // wxICON_XXX values
    virtual wxIcon GetStdIcon(int which) const = 0;

        // VZ: what does this do exactly?
    void SetWantDebugOutput( bool flag ) { m_wantDebugOutput = flag; }
    bool GetWantDebugOutput() const { return m_wantDebugOutput; }

        // set use of best visual flag (see below)
    void SetUseBestVisual( bool flag ) { m_useBestVisual = flag; }
    bool GetUseBestVisual() const { return m_useBestVisual; }

        // set/get printing mode: see wxPRINT_XXX constants.
        //
        // default behaviour is the normal one for Unix: always use PostScript
        // printing.
    virtual void SetPrintMode(int WXUNUSED(mode)) { }
    int GetPrintMode() const { return wxPRINT_POSTSCRIPT; }

    // called by toolkit-specific code to set the app status: active (we have
    // focus) or not and also the last window which had focus before we were
    // deactivated
    virtual void SetActive(bool isActive, wxWindow *lastFocus);
#endif // wxUSE_GUI

    // debugging support
    // -----------------

    // this function is called when an assert failure occurs, the base class
    // version does the normal processing (i.e. shows the usual assert failure
    // dialog box)
#ifdef __WXDEBUG__
    virtual void OnAssert(const wxChar *file, int line, const wxChar *msg);
#endif // __WXDEBUG__

    // implementation only from now on
    // -------------------------------

    // helpers for dynamic wxApp construction
    static void SetInitializerFunction(wxAppInitializerFunction fn)
        { m_appInitFn = fn; }
    static wxAppInitializerFunction GetInitializerFunction()
        { return m_appInitFn; }

    // needed to avoid link errors
#ifdef __DARWIN__
    virtual ~wxAppBase() { }
#endif

    // process all events in the wxPendingEvents list
    virtual void ProcessPendingEvents();

    // access to the command line arguments
    int      argc;
    wxChar **argv;

protected:
    // function used for dynamic wxApp creation
    static wxAppInitializerFunction m_appInitFn;

    // application info (must be set from the user code)
    wxString m_vendorName,      // vendor name (ACME Inc)
             m_appName,         // app name
             m_className;       // class name

    // TRUE if the application wants to get debug output
    bool m_wantDebugOutput;

#if wxUSE_GUI
    // the main top level window - may be NULL
    wxWindow *m_topWindow;

    // if TRUE, exit the main loop when the last top level window is deleted
    bool m_exitOnFrameDelete;

    // TRUE if the apps whats to use the best visual on systems where
    // more than one are available (Sun, SGI, XFree86 4.0 ?)
    bool m_useBestVisual;

    // does any of our windows has focus?
    bool m_isActive;
#endif // wxUSE_GUI
};

// ----------------------------------------------------------------------------
// now include the declaration of the real class
// ----------------------------------------------------------------------------

#if wxUSE_GUI
    #if defined(__WXMSW__)
        #include "wx/msw/app.h"
    #elif defined(__WXMOTIF__)
        #include "wx/motif/app.h"
    #elif defined(__WXMGL__)
        #include "wx/mgl/app.h"
    #elif defined(__WXGTK__)
        #include "wx/gtk/app.h"
    #elif defined(__WXMAC__)
        #include "wx/mac/app.h"
    #elif defined(__WXPM__)
        #include "wx/os2/app.h"
    #elif defined(__WXSTUBS__)
        #include "wx/stubs/app.h"
    #endif
#else // !GUI
    // can't use typedef because wxApp forward declared as a class
    class WXDLLEXPORT wxApp : public wxAppBase
    {
    };
#endif // GUI/!GUI

// ----------------------------------------------------------------------------
// the global data
// ----------------------------------------------------------------------------

// the one and only application object - use of wxTheApp in application code
// is discouraged, consider using DECLARE_APP() after which you may call
// wxGetApp() which will return the object of the correct type (i.e. MyApp and
// not wxApp)
WXDLLEXPORT_DATA(extern wxApp*) wxTheApp;

// ----------------------------------------------------------------------------
// global functions
// ----------------------------------------------------------------------------

// event loop related functions only work in GUI programs
// ------------------------------------------------------

// Force an exit from main loop
extern void WXDLLEXPORT wxExit();

// Yield to other apps/messages
extern bool WXDLLEXPORT wxYield();

// Yield to other apps/messages
extern void WXDLLEXPORT wxWakeUpIdle();

// Post a message to the given eventhandler which will be processed during the
// next event loop iteration
inline void wxPostEvent(wxEvtHandler *dest, wxEvent& event)
{
    wxCHECK_RET( dest, wxT("need an object to post event to in wxPostEvent") );

#if wxUSE_GUI
    dest->AddPendingEvent(event);
#else
    dest->ProcessEvent(event);
#endif // wxUSE_GUI
}

// console applications may avoid using DECLARE_APP and IMPLEMENT_APP macros
// and call these functions instead at the program startup and termination
// -------------------------------------------------------------------------

#if !wxUSE_GUI

// initialize the library (may be called as many times as needed, but each
// call to wxInitialize() must be matched by wxUninitialize())
extern bool WXDLLEXPORT wxInitialize();

// clean up - the library can't be used any more after the last call to
// wxUninitialize()
extern void WXDLLEXPORT wxUninitialize();

// create an object of this class on stack to initialize/cleanup thel ibrary
// automatically
class WXDLLEXPORT wxInitializer
{
public:
    // initialize the library
    wxInitializer() { m_ok = wxInitialize(); }

    // has the initialization been successful? (explicit test)
    bool IsOk() const { return m_ok; }

    // has the initialization been successful? (implicit test)
    operator bool() const { return m_ok; }

    // dtor only does clean up if we initialized the library properly
    ~wxInitializer() { if ( m_ok ) wxUninitialize(); }

private:
    bool m_ok;
};

#endif // !wxUSE_GUI

// ----------------------------------------------------------------------------
// macros for dynamic creation of the application object
// ----------------------------------------------------------------------------

// Having a global instance of this class allows wxApp to be aware of the app
// creator function. wxApp can then call this function to create a new app
// object. Convoluted, but necessary.

class WXDLLEXPORT wxAppInitializer
{
public:
    wxAppInitializer(wxAppInitializerFunction fn)
        { wxApp::SetInitializerFunction(fn); }
};

// Here's a macro you can use if your compiler really, really wants main() to
// be in your main program (e.g. hello.cpp). Now IMPLEMENT_APP should add this
// code if required.

#if !wxUSE_GUI || defined(__WXMOTIF__) || defined(__WXGTK__) || defined(__WXPM__) || defined(__WXMGL__)
    #define IMPLEMENT_WXWIN_MAIN \
        extern int wxEntry( int argc, char *argv[] ); \
        int main(int argc, char *argv[]) { return wxEntry(argc, argv); }
#elif defined(__WXMAC__) && defined(__UNIX__)
    // wxMac seems to have a specific wxEntry prototype
    #define IMPLEMENT_WXWIN_MAIN \
        extern int wxEntry( int argc, char *argv[], bool enterLoop = 1 ); \
        int main(int argc, char *argv[]) { return wxEntry(argc, argv); }
#elif defined(__WXMSW__) && defined(WXUSINGDLL)
    // NT defines APIENTRY, 3.x not
    #if !defined(WXAPIENTRY)
        #define WXAPIENTRY WXFAR wxSTDCALL
    #endif

    #include <windows.h>
    #include "wx/msw/winundef.h"

    #define IMPLEMENT_WXWIN_MAIN \
        extern "C" int WXAPIENTRY WinMain(HINSTANCE hInstance,\
                                          HINSTANCE hPrevInstance,\
                                          LPSTR m_lpCmdLine, int nCmdShow)\
        {\
            return wxEntry((WXHINSTANCE) hInstance,\
                           (WXHINSTANCE) hPrevInstance,\
                           m_lpCmdLine, nCmdShow);\
        }
#else
    #define IMPLEMENT_WXWIN_MAIN
#endif

#ifdef __WXUNIVERSAL__
    #include "wx/univ/theme.h"

    #define IMPLEMENT_WX_THEME_SUPPORT \
        WX_USE_THEME(win32); \
        WX_USE_THEME(gtk);
#else
    #define IMPLEMENT_WX_THEME_SUPPORT
#endif

// Use this macro if you want to define your own main() or WinMain() function
// and call wxEntry() from there.
#define IMPLEMENT_APP_NO_MAIN(appname)                   \
    wxApp *wxCreateApp() { return new appname; }         \
    wxAppInitializer wxTheAppInitializer((wxAppInitializerFunction) wxCreateApp); \
    appname& wxGetApp() { return *(appname *)wxTheApp; }

// Same as IMPLEMENT_APP() normally but doesn't include themes support in
// wxUniversal builds
#define IMPLEMENT_APP_NO_THEMES(appname)    \
    IMPLEMENT_APP_NO_MAIN(appname)          \
    IMPLEMENT_WXWIN_MAIN

// Use this macro exactly once, the argument is the name of the wxApp-derived
// class which is the class of your application.
#define IMPLEMENT_APP(appname)              \
    IMPLEMENT_APP_NO_THEMES(appname)        \
    IMPLEMENT_WX_THEME_SUPPORT

// this macro can be used multiple times and just allows you to use wxGetApp()
// function
#define DECLARE_APP(appname) extern appname& wxGetApp();

#endif
    // _WX_APP_H_BASE_