view src/main/win32/SDL_win32_main.c @ 4139:568c9b3c0167 SDL-1.2

* Added configure option --enable-screensaver, to allow enabling the screensaver by default. * Use XResetScreenSaver() instead of disabling screensaver entirely. Full discussion summary from Erik on the SDL mailing list: Current behaviour ================= SDL changes the user's display power management settings without permission from the user and without telling the user. The interface that it uses to do so is DPMSDisable/DPMSEnable, which should only ever be used by configuration utilities like KControl, never by normal application programs, let alone by the libraries that they use. Using an interface that is not at all intended for what SDL tries to achieve means that it will not work as it should. Firstly, the power management is completely disabled during the whole lifetime of the SDL program, not only when it should be. Secondly, it makes SDL non-reentrant, meaning that things will break when multiple SDL programs are clients of the same X server simultaneously. Thirdly, no cleanup mechanism ensures that the setting is restored if the client does not do that (for example if it crashes). In addition to that, this interface is broken on xorg, [http://bugs.freedesktop.org/show_bug.cgi?id=13962], so what SDL tries to do does not work at all on that implementation of the X Window System. (The reason that the DPMSEnable works in KControl is that it calls DPMSSetTimeout immediately after, [http://websvn.kde.org/tags/KDE/3.5.9/kdebase/kcontrol/energy/energy.cpp?annotate=774532#l343]). The problems that the current behaviour causes ============================================== 1. Information leak. When the user is away, someone might see what the user has on the display when the user counts on the screensaver preventing this. This does not even require physical access to the workstation, it is enough to see it from a distance. 2. Draining battery. An SDL program that runs on a laptop will quickly drain the battery while the user is away. The system will soon shut down and require recharging before being usable again, while it should in fact have consumed very little energy if the user's settings would have been obeyed. 3. Wasting energy. Even if battery issues are not considered, energy as such is wasted. 4. Display wear. The display may be worn out. The problems that the current behaviour tries to solve ====================================================== 1. Preventing screensaver while playing movies. Many SDL applications are media players. They have reasons to prevent screensavers from being activated while a movie is being played. When a user clicks on the play button it can be interpreted as saying "play this movie, but do not turn off the display while playing it, because I will watch it even though I do not interact with the system". 2. Preventing screensaver when some input bypasses X. Sometimes SDL uses input from another source than the X server, so that the X server is bypassed. This obviously breaks the screensaver handling. SDL tries to work around that. 3. Preventing screensaver when all input bypasses X. There is something called Direct Graphics Access mode, where a program takes control of both the display and the input devices from the X server. This obviously means that the X server can not handle the screensaver alone, since screensaver handling depends on input handling. SDL does not do what it should to help the X server to handle the screensaver. Nor does SDL take care of screeensaver handling itself. SDL simply disables the screensaver completely. How the problems should be solved ================================= The correct way for an application program to prevent the screensaver under X is to call XResetScreenSaver. This was recently discovered and implemented by the mplayer developers, [http://svn.mplayerhq.hu/mplayer?view=rev&revision=25637]. SDL needs to wrap this in an API call (SDL_ResetScreenSaver) and implement it for the other video targets (if they do not have a corresponding call, SDL should do what it takes on that particular target, for example sending fake key events). 1. When a movie is played, the player should reset the screensaver when the animation is advanced to a new frame. The same applies to anything similar, like slideshows. 2. When the X server is handling input, it must handle all input (keyboards, mice, gamepads, ...). This is necessary, not only to be able to handle the screensaver, but also so that it can send the events to the correct (the currently active) client. If there is an input device that the X server can not handle for some reason (such as lack of Plug and Play capability), the program that handles the device as a workaround must simulate what would happen if the X server would have handled the device, by calling XResetScreenSaver when input is received from the device. 3. When the X server is not handling the input, it depends on the program that does to call XResetScreenSaver whenever an input event occurs. Alternatively the program must handle the screensaver countdown internally and call XActivateScreenSaver.
author Sam Lantinga <slouken@libsdl.org>
date Fri, 29 Feb 2008 13:55:44 +0000
parents 3c068a8c016f
children 8b8314cc34a6
line wrap: on
line source

/*
    SDL_main.c, placed in the public domain by Sam Lantinga  4/13/98

    The WinMain function -- calls your program's main() function
*/

#include <stdio.h>
#include <stdlib.h>

#define WIN32_LEAN_AND_MEAN
#include <windows.h>

#ifdef _WIN32_WCE
# define DIR_SEPERATOR TEXT("\\")
# undef _getcwd
# define _getcwd(str,len)	wcscpy(str,TEXT(""))
# define setbuf(f,b)
# define setvbuf(w,x,y,z)
# define fopen		_wfopen
# define freopen	_wfreopen
# define remove(x)	DeleteFile(x)
#else
# define DIR_SEPERATOR TEXT("/")
# include <direct.h>
#endif

/* Include the SDL main definition header */
#include "SDL.h"
#include "SDL_main.h"

#ifdef main
# ifndef _WIN32_WCE_EMULATION
#  undef main
# endif /* _WIN32_WCE_EMULATION */
#endif /* main */

/* The standard output files */
#define STDOUT_FILE	TEXT("stdout.txt")
#define STDERR_FILE	TEXT("stderr.txt")

#ifndef NO_STDIO_REDIRECT
# ifdef _WIN32_WCE
  static wchar_t stdoutPath[MAX_PATH];
  static wchar_t stderrPath[MAX_PATH];
# else
  static char stdoutPath[MAX_PATH];
  static char stderrPath[MAX_PATH];
# endif
#endif

#if defined(_WIN32_WCE) && _WIN32_WCE < 300
/* seems to be undefined in Win CE although in online help */
#define isspace(a) (((CHAR)a == ' ') || ((CHAR)a == '\t'))
#endif /* _WIN32_WCE < 300 */

static void UnEscapeQuotes( char *arg )
{
	char *last = NULL;

	while( *arg ) {
		if( *arg == '"' && *last == '\\' ) {
			char *c_curr = arg;
			char *c_last = last;

			while( *c_curr ) {
				*c_last = *c_curr;
				c_last = c_curr;
				c_curr++;
			}
			*c_last = '\0';
		}
		last = arg;
		arg++;
	}
}

/* Parse a command line buffer into arguments */
static int ParseCommandLine(char *cmdline, char **argv)
{
	char *bufp;
	char *lastp = NULL;
	int argc, last_argc;

	argc = last_argc = 0;
	for ( bufp = cmdline; *bufp; ) {
		/* Skip leading whitespace */
		while ( isspace(*bufp) ) {
			++bufp;
		}
		/* Skip over argument */
		if ( *bufp == '"' ) {
			++bufp;
			if ( *bufp ) {
				if ( argv ) {
					argv[argc] = bufp;
				}
				++argc;
			}
			/* Skip over word */
			while ( *bufp && ( *bufp != '"' || *lastp == '\\' ) ) {
				lastp = bufp;
				++bufp;
			}
		} else {
			if ( *bufp ) {
				if ( argv ) {
					argv[argc] = bufp;
				}
				++argc;
			}
			/* Skip over word */
			while ( *bufp && ! isspace(*bufp) ) {
				++bufp;
			}
		}
		if ( *bufp ) {
			if ( argv ) {
				*bufp = '\0';
			}
			++bufp;
		}

		/* Strip out \ from \" sequences */
		if( argv && last_argc != argc ) {
			UnEscapeQuotes( argv[last_argc] );	
		}
		last_argc = argc;	
	}
	if ( argv ) {
		argv[argc] = NULL;
	}
	return(argc);
}

/* Show an error message */
static void ShowError(const char *title, const char *message)
{
/* If USE_MESSAGEBOX is defined, you need to link with user32.lib */
#ifdef USE_MESSAGEBOX
	MessageBox(NULL, message, title, MB_ICONEXCLAMATION|MB_OK);
#else
	fprintf(stderr, "%s: %s\n", title, message);
#endif
}

/* Pop up an out of memory message, returns to Windows */
static BOOL OutOfMemory(void)
{
	ShowError("Fatal Error", "Out of memory - aborting");
	return FALSE;
}

/* SDL_Quit() shouldn't be used with atexit() directly because
   calling conventions may differ... */
static void cleanup(void)
{
	SDL_Quit();
}

/* Remove the output files if there was no output written */
static void cleanup_output(void)
{
#ifndef NO_STDIO_REDIRECT
	FILE *file;
	int empty;
#endif

	/* Flush the output in case anything is queued */
	fclose(stdout);
	fclose(stderr);

#ifndef NO_STDIO_REDIRECT
	/* See if the files have any output in them */
	if ( stdoutPath[0] ) {
		file = fopen(stdoutPath, TEXT("rb"));
		if ( file ) {
			empty = (fgetc(file) == EOF) ? 1 : 0;
			fclose(file);
			if ( empty ) {
				remove(stdoutPath);
			}
		}
	}
	if ( stderrPath[0] ) {
		file = fopen(stderrPath, TEXT("rb"));
		if ( file ) {
			empty = (fgetc(file) == EOF) ? 1 : 0;
			fclose(file);
			if ( empty ) {
				remove(stderrPath);
			}
		}
	}
#endif
}

#if defined(_MSC_VER) && !defined(_WIN32_WCE)
/* The VC++ compiler needs main defined */
#define console_main main
#endif

/* This is where execution begins [console apps] */
int console_main(int argc, char *argv[])
{
	size_t n;
	char *bufp, *appname;
	int status;

	/* Get the class name from argv[0] */
	appname = argv[0];
	if ( (bufp=SDL_strrchr(argv[0], '\\')) != NULL ) {
		appname = bufp+1;
	} else
	if ( (bufp=SDL_strrchr(argv[0], '/')) != NULL ) {
		appname = bufp+1;
	}

	if ( (bufp=SDL_strrchr(appname, '.')) == NULL )
		n = SDL_strlen(appname);
	else
		n = (bufp-appname);

	bufp = SDL_stack_alloc(char, n+1);
	if ( bufp == NULL ) {
		return OutOfMemory();
	}
	SDL_strlcpy(bufp, appname, n+1);
	appname = bufp;

	/* Load SDL dynamic link library */
	if ( SDL_Init(SDL_INIT_NOPARACHUTE) < 0 ) {
		ShowError("WinMain() error", SDL_GetError());
		return(FALSE);
	}
	atexit(cleanup_output);
	atexit(cleanup);

	/* Sam:
	   We still need to pass in the application handle so that
	   DirectInput will initialize properly when SDL_RegisterApp()
	   is called later in the video initialization.
	 */
	SDL_SetModuleHandle(GetModuleHandle(NULL));

	/* Run the application main() code */
	status = SDL_main(argc, argv);

	/* Exit cleanly, calling atexit() functions */
	exit(status);

	/* Hush little compiler, don't you cry... */
	return 0;
}

/* This is where execution begins [windowed apps] */
#ifdef _WIN32_WCE
int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrev, LPWSTR szCmdLine, int sw)
#else
int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrev, LPSTR szCmdLine, int sw)
#endif
{
	HINSTANCE handle;
	char **argv;
	int argc;
	char *cmdline;
#ifdef _WIN32_WCE
	wchar_t *bufp;
	int nLen;
#else
	char *bufp;
	size_t nLen;
#endif
#ifndef NO_STDIO_REDIRECT
	DWORD pathlen;
#ifdef _WIN32_WCE
	wchar_t path[MAX_PATH];
#else
	char path[MAX_PATH];
#endif
	FILE *newfp;
#endif

	/* Start up DDHELP.EXE before opening any files, so DDHELP doesn't
	   keep them open.  This is a hack.. hopefully it will be fixed 
	   someday.  DDHELP.EXE starts up the first time DDRAW.DLL is loaded.
	 */
	handle = LoadLibrary(TEXT("DDRAW.DLL"));
	if ( handle != NULL ) {
		FreeLibrary(handle);
	}

#ifndef NO_STDIO_REDIRECT
	pathlen = GetModuleFileName(NULL, path, SDL_arraysize(path));
	while ( pathlen > 0 && path[pathlen] != '\\' ) {
		--pathlen;
	}
	path[pathlen] = '\0';

#ifdef _WIN32_WCE
	wcsncpy( stdoutPath, path, SDL_arraysize(stdoutPath) );
	wcsncat( stdoutPath, DIR_SEPERATOR STDOUT_FILE, SDL_arraysize(stdoutPath) );
#else
	SDL_strlcpy( stdoutPath, path, SDL_arraysize(stdoutPath) );
	SDL_strlcat( stdoutPath, DIR_SEPERATOR STDOUT_FILE, SDL_arraysize(stdoutPath) );
#endif
    
	/* Redirect standard input and standard output */
	newfp = freopen(stdoutPath, TEXT("w"), stdout);

#ifndef _WIN32_WCE
	if ( newfp == NULL ) {	/* This happens on NT */
#if !defined(stdout)
		stdout = fopen(stdoutPath, TEXT("w"));
#else
		newfp = fopen(stdoutPath, TEXT("w"));
		if ( newfp ) {
			*stdout = *newfp;
		}
#endif
	}
#endif /* _WIN32_WCE */

#ifdef _WIN32_WCE
	wcsncpy( stderrPath, path, SDL_arraysize(stdoutPath) );
	wcsncat( stderrPath, DIR_SEPERATOR STDOUT_FILE, SDL_arraysize(stdoutPath) );
#else
	SDL_strlcpy( stderrPath, path, SDL_arraysize(stderrPath) );
	SDL_strlcat( stderrPath, DIR_SEPERATOR STDERR_FILE, SDL_arraysize(stderrPath) );
#endif

	newfp = freopen(stderrPath, TEXT("w"), stderr);
#ifndef _WIN32_WCE
	if ( newfp == NULL ) {	/* This happens on NT */
#if !defined(stderr)
		stderr = fopen(stderrPath, TEXT("w"));
#else
		newfp = fopen(stderrPath, TEXT("w"));
		if ( newfp ) {
			*stderr = *newfp;
		}
#endif
	}
#endif /* _WIN32_WCE */

	setvbuf(stdout, NULL, _IOLBF, BUFSIZ);	/* Line buffered */
	setbuf(stderr, NULL);			/* No buffering */
#endif /* !NO_STDIO_REDIRECT */

#ifdef _WIN32_WCE
	nLen = wcslen(szCmdLine)+128+1;
	bufp = SDL_stack_alloc(wchar_t, nLen*2);
	wcscpy (bufp, TEXT("\""));
	GetModuleFileName(NULL, bufp+1, 128-3);
	wcscpy (bufp+wcslen(bufp), TEXT("\" "));
	wcsncpy(bufp+wcslen(bufp), szCmdLine,nLen-wcslen(bufp));
	nLen = wcslen(bufp)+1;
	cmdline = SDL_stack_alloc(char, nLen);
	if ( cmdline == NULL ) {
		return OutOfMemory();
	}
	WideCharToMultiByte(CP_ACP, 0, bufp, -1, cmdline, nLen, NULL, NULL);
#else
	/* Grab the command line */
	bufp = GetCommandLine();
	nLen = SDL_strlen(bufp)+1;
	cmdline = SDL_stack_alloc(char, nLen);
	if ( cmdline == NULL ) {
		return OutOfMemory();
	}
	SDL_strlcpy(cmdline, bufp, nLen);
#endif

	/* Parse it into argv and argc */
	argc = ParseCommandLine(cmdline, NULL);
	argv = SDL_stack_alloc(char*, argc+1);
	if ( argv == NULL ) {
		return OutOfMemory();
	}
	ParseCommandLine(cmdline, argv);

	/* Run the main program (after a little SDL initialization) */
	console_main(argc, argv);

	/* Hush little compiler, don't you cry... */
	return 0;
}