if.c

ReactOS是一些高手根据Windows XP的内核编写出的类XP。内核实现机理和API函数调用几乎相同。甚至可以兼容XP的程序。喜欢研究系统内核的人可以看一看。

/*
 *  IF.C - if internal batch command.
 *
 *
 *  History:
 *
 *    16 Jul 1998 (Hans B Pufal)
 *        started.
 *
 *    16 Jul 1998 (John P Price)
 *        Seperated commands into individual files.
 *
 *    27-Jul-1998 (John P Price <[e-mail]>)
 *        added config.h include
 *
 *    07-Jan-1999 (Eric Kohl)
 *        Added help text ("if /?") and cleaned up.
 *
 *    21-Jan-1999 (Eric Kohl)
 *        Unicode and redirection ready!
 *
 *    01-Sep-1999 (Eric Kohl)
 *        Fixed help text.
 *
 *    17-Feb-2001 (ea)
 *        IF DEFINED variable command
 *
 *    28-Apr-2005 (Magnus Olsen) <[e-mail]>)
 *        Remove all hardcode string to En.rc
 *
 */

#include <precomp.h>


#define X_EXEC 1
#define X_EMPTY 0x80

INT cmd_if (LPTSTR cmd, LPTSTR param)
{
	INT x_flag = 0; /* when set cause 'then' clause to be executed */
	LPTSTR pp;

#ifdef _DEBUG
	DebugPrintf (_T("cmd_if: (\'%s\', \'%s\')\n"), cmd, param);
#endif

	if (!_tcsncmp (param, _T("/?"), 2))
	{
		ConOutResPaging(TRUE,STRING_IF_HELP1);
		return 0;
	}

	/* First check if param string begins with 'not' */
	if (!_tcsnicmp (param, _T("not"), 3) && _istspace (*(param + 3)))
	{
		x_flag = X_EXEC;            /* Remember 'NOT' */
		param += 3;                 /* Step over 'NOT' */
		while (_istspace (*param))  /* And subsequent spaces */
			param++;
	}

	/* Check for 'exist' form */
	if (!_tcsnicmp (param, _T("exist"), 5) && _istspace (*(param + 5)))
	{
		UINT i;
		BOOL bInside = FALSE;

		param += 5;
		while (_istspace (*param))
			param++;

		pp = param;

		/* find the whole path to the file */
		for(i = 0; i < _tcslen(param); i++)
		{
			if(param[i] == _T('\"')) 
				bInside = !bInside;
			if((param[i] == _T(' ')) && !bInside)
			{					
				break;
			}
			pp++;
		}
		*pp++ = _T('\0');
		i = 0;
		/* remove quotes */
		while(i < _tcslen(param))
		{
			if(param[i] == _T('\"'))
				memmove(&param[i],&param[i + 1], _tcslen(&param[i]) * sizeof(TCHAR));
			else
				i++;
		}

		if (*pp)
		{			
			WIN32_FIND_DATA f;
			HANDLE hFind;
			
			hFind = FindFirstFile (param, &f);
			x_flag ^= (hFind == INVALID_HANDLE_VALUE) ? 0 : X_EXEC;
			if (hFind != INVALID_HANDLE_VALUE)
			{
				FindClose (hFind);
			}
		}
		else
			return 0;
	}
	else if (!_tcsnicmp (param, _T("defined"), 7) && _istspace (*(param + 7)))
	{
		/* Check for 'defined' form */
		TCHAR Value [1];
		INT   ValueSize = 0;

		param += 7;
		/* IF [NOT] DEFINED var COMMAND */
		/*                 ^            */
		while (_istspace (*param))
			param++;
		/* IF [NOT] DEFINED var COMMAND */
		/*                  ^           */
		pp = param;
		while (*pp && !_istspace (*pp))
			pp++;
		/* IF [NOT] DEFINED var COMMAND */
		/*                     ^        */
		if (*pp)
		{
			*pp++ = _T('\0');
			ValueSize = GetEnvironmentVariable(param, Value, sizeof(Value) / sizeof(Value[0]));
			x_flag ^= (0 == ValueSize)
					? 0
					: X_EXEC;
			x_flag |= X_EMPTY;
		}
		else
			return 0;
	}
	else if (!_tcsnicmp (param, _T("errorlevel"), 10) && _istspace (*(param + 10)))
	{
		/* Check for 'errorlevel' form */
		INT n = 0;

		pp = param + 10;
		while (_istspace (*pp))
			pp++;

		while (_istdigit (*pp))
			n = n * 10 + (*pp++ - _T('0'));

		x_flag ^= (nErrorLevel != n) ? 0 : X_EXEC;

		x_flag |= X_EMPTY;          /* Syntax error if comd empty */
	}
	else
	{
		BOOL bInQuote = FALSE;
		INT p1len;
		pp = param;
		while ( *pp && ( bInQuote || *pp != _T('=') ) )
		{
			if ( *pp == _T('\"') )
				bInQuote = !bInQuote;
			++pp;
		}
		p1len = pp-param;
		/* check for "==" */
		if ( *pp++ != _T('=') || *pp++ != _T('=') )
		{
			error_syntax ( NULL );
			return 1;
		}
		while (_istspace (*pp)) /* Skip subsequent spaces */
			pp++;

		/* are the two sides equal*/
		if ( !_tcsncmp(param,pp,p1len))
			x_flag ^= X_EXEC;
		pp += p1len;

		if ( x_flag )
		{
			x_flag |= X_EMPTY;
		}
	}

	if (x_flag & X_EMPTY)
	{
		while (_istspace (*pp)) /* Then skip spaces */
			pp++;

		if (*pp == _T('\0'))    /* If nothing left then syntax err */
		{
			error_syntax (NULL);
			return 1;
		}
	}

	if (x_flag & X_EXEC)
	{
		ParseCommandLine (pp);
	}

	return 0;
}

/* EOF */