cond.c

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/*
 * Copyright (c) 1988, 1989, 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 * Copyright (c) 1989 by Berkeley Softworks
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Adam de Boor.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
static char sccsid[] = "@(#)cond.c	8.2 (Berkeley) 1/2/94";
#endif /* not lint */

/*-
 * cond.c --
 *	Functions to handle conditionals in a makefile.
 *
 * Interface:
 *	Cond_Eval 	Evaluate the conditional in the passed line.
 *
 */

#include    <ctype.h>
#include    <math.h>
#include    "make.h"
#include    "hash.h"
#include    "dir.h"
#include    "buf.h"

/*
 * The parsing of conditional expressions is based on this grammar:
 *	E -> F || E
 *	E -> F
 *	F -> T && F
 *	F -> T
 *	T -> defined(variable)
 *	T -> make(target)
 *	T -> exists(file)
 *	T -> empty(varspec)
 *	T -> target(name)
 *	T -> symbol
 *	T -> $(varspec) op value
 *	T -> $(varspec) == "string"
 *	T -> $(varspec) != "string"
 *	T -> ( E )
 *	T -> ! T
 *	op -> == | != | > | < | >= | <=
 *
 * 'symbol' is some other symbol to which the default function (condDefProc)
 * is applied.
 *
 * Tokens are scanned from the 'condExpr' string. The scanner (CondToken)
 * will return And for '&' and '&&', Or for '|' and '||', Not for '!',
 * LParen for '(', RParen for ')' and will evaluate the other terminal
 * symbols, using either the default function or the function given in the
 * terminal, and return the result as either True or False.
 *
 * All Non-Terminal functions (CondE, CondF and CondT) return Err on error.
 */
typedef enum {
    And, Or, Not, True, False, LParen, RParen, EndOfFile, None, Err
} Token;

/*-
 * Structures to handle elegantly the different forms of #if's. The
 * last two fields are stored in condInvert and condDefProc, respectively.
 */
static int CondGetArg __P((char **, char **, char *, Boolean));
static Boolean CondDoDefined __P((int, char *));
static int CondStrMatch __P((char *, char *));
static Boolean CondDoMake __P((int, char *));
static Boolean CondDoExists __P((int, char *));
static Boolean CondDoTarget __P((int, char *));
static Boolean CondCvtArg __P((char *, double *));
static Token CondToken __P((Boolean));
static Token CondT __P((Boolean));
static Token CondF __P((Boolean));
static Token CondE __P((Boolean));

static struct If {
    char	*form;	      /* Form of if */
    int		formlen;      /* Length of form */
    Boolean	doNot;	      /* TRUE if default function should be negated */
    Boolean	(*defProc)(); /* Default function to apply */
} ifs[] = {
    { "ifdef",	  5,	  FALSE,  CondDoDefined },
    { "ifndef",	  6,	  TRUE,	  CondDoDefined },
    { "ifmake",	  6,	  FALSE,  CondDoMake },
    { "ifnmake",  7,	  TRUE,	  CondDoMake },
    { "if",	  2,	  FALSE,  CondDoDefined },
    { (char *)0,  0,	  FALSE,  (Boolean (*)())0 }
};

static Boolean	  condInvert;	    	/* Invert the default function */
static Boolean	  (*condDefProc)(); 	/* Default function to apply */
static char 	  *condExpr;	    	/* The expression to parse */
static Token	  condPushBack=None;	/* Single push-back token used in
					 * parsing */

#define	MAXIF		30	  /* greatest depth of #if'ing */

static Boolean	  condStack[MAXIF]; 	/* Stack of conditionals's values */
static int  	  condTop = MAXIF;  	/* Top-most conditional */
static int  	  skipIfLevel=0;    	/* Depth of skipped conditionals */
static Boolean	  skipLine = FALSE; 	/* Whether the parse module is skipping
					 * lines */

/*-
 *-----------------------------------------------------------------------
 * CondPushBack --
 *	Push back the most recent token read. We only need one level of
 *	this, so the thing is just stored in 'condPushback'.
 *
 * Results:
 *	None.
 *
 * Side Effects:
 *	condPushback is overwritten.
 *
 *-----------------------------------------------------------------------
 */
static void
CondPushBack (t)
    Token   	  t;	/* Token to push back into the "stream" */
{
    condPushBack = t;
}

/*-
 *-----------------------------------------------------------------------
 * CondGetArg --
 *	Find the argument of a built-in function.
 *
 * Results:
 *	The length of the argument and the address of the argument.
 *
 * Side Effects:
 *	The pointer is set to point to the closing parenthesis of the
 *	function call.
 *
 *-----------------------------------------------------------------------
 */
static int
CondGetArg (linePtr, argPtr, func, parens)
    char    	  **linePtr;
    char    	  **argPtr;
    char    	  *func;
    Boolean 	  parens;   	/* TRUE if arg should be bounded by parens */
{
    register char *cp;
    int	    	  argLen;
    register Buffer buf;

    cp = *linePtr;
    if (parens) {
	while (*cp != '(' && *cp != '\0') {
	    cp++;
	}
	if (*cp == '(') {
	    cp++;
	}
    }

    if (*cp == '\0') {
	/*
	 * No arguments whatsoever. Because 'make' and 'defined' aren't really
	 * "reserved words", we don't print a message. I think this is better
	 * than hitting the user with a warning message every time s/he uses
	 * the word 'make' or 'defined' at the beginning of a symbol...
	 */
	*argPtr = cp;
	return (0);
    }

    while (*cp == ' ' || *cp == '\t') {
	cp++;
    }

    /*
     * Create a buffer for the argument and start it out at 16 characters
     * long. Why 16? Why not?
     */
    buf = Buf_Init(16);
    
    while ((strchr(" \t)&|", *cp) == (char *)NULL) && (*cp != '\0')) {
	if (*cp == '$') {
	    /*
	     * Parse the variable spec and install it as part of the argument
	     * if it's valid. We tell Var_Parse to complain on an undefined
	     * variable, so we don't do it too. Nor do we return an error,
	     * though perhaps we should...
	     */
	    char  	*cp2;
	    int		len;
	    Boolean	doFree;

	    cp2 = Var_Parse(cp, VAR_CMD, TRUE, &len, &doFree);

	    Buf_AddBytes(buf, strlen(cp2), (Byte *)cp2);
	    if (doFree) {
		free(cp2);
	    }
	    cp += len;
	} else {
	    Buf_AddByte(buf, (Byte)*cp);
	    cp++;
	}
    }

    Buf_AddByte(buf, (Byte)'\0');
    *argPtr = (char *)Buf_GetAll(buf, &argLen);
    Buf_Destroy(buf, FALSE);

    while (*cp == ' ' || *cp == '\t') {
	cp++;
    }
    if (parens && *cp != ')') {
	Parse_Error (PARSE_WARNING, "Missing closing parenthesis for %s()",
		     func);
	return (0);
    } else if (parens) {
	/*
	 * Advance pointer past close parenthesis.
	 */
	cp++;
    }
    
    *linePtr = cp;
    return (argLen);
}

/*-
 *-----------------------------------------------------------------------
 * CondDoDefined --
 *	Handle the 'defined' function for conditionals.
 *
 * Results:
 *	TRUE if the given variable is defined.
 *
 * Side Effects:
 *	None.
 *
 *-----------------------------------------------------------------------
 */
static Boolean
CondDoDefined (argLen, arg)
    int	    argLen;
    char    *arg;
{
    char    savec = arg[argLen];
    Boolean result;

    arg[argLen] = '\0';
    if (Var_Value (arg, VAR_CMD) != (char *)NULL) {
	result = TRUE;
    } else {
	result = FALSE;
    }
    arg[argLen] = savec;
    return (result);
}

/*-
 *-----------------------------------------------------------------------
 * CondStrMatch --
 *	Front-end for Str_Match so it returns 0 on match and non-zero
 *	on mismatch. Callback function for CondDoMake via Lst_Find
 *
 * Results:
 *	0 if string matches pattern
 *
 * Side Effects:
 *	None
 *
 *-----------------------------------------------------------------------
 */
static int
CondStrMatch(string, pattern)
    char    *string;
    char    *pattern;
{
    return(!Str_Match(string,pattern));
}

/*-
 *-----------------------------------------------------------------------
 * CondDoMake --
 *	Handle the 'make' function for conditionals.
 *
 * Results:
 *	TRUE if the given target is being made.
 *
 * Side Effects:
 *	None.
 *
 *-----------------------------------------------------------------------
 */
static Boolean
CondDoMake (argLen, arg)
    int	    argLen;
    char    *arg;
{
    char    savec = arg[argLen];
    Boolean result;

    arg[argLen] = '\0';
    if (Lst_Find (create, (ClientData)arg, CondStrMatch) == NILLNODE) {
	result = FALSE;
    } else {
	result = TRUE;
    }
    arg[argLen] = savec;
    return (result);
}

/*-
 *-----------------------------------------------------------------------
 * CondDoExists --
 *	See if the given file exists.
 *
 * Results:
 *	TRUE if the file exists and FALSE if it does not.
 *
 * Side Effects:
 *	None.
 *
 *-----------------------------------------------------------------------
 */
static Boolean
CondDoExists (argLen, arg)
    int	    argLen;
    char    *arg;
{
    char    savec = arg[argLen];
    Boolean result;
    char    *path;

    arg[argLen] = '\0';
    path = Dir_FindFile(arg, dirSearchPath);
    if (path != (char *)NULL) {
	result = TRUE;
	free(path);
    } else {
	result = FALSE;
    }
    arg[argLen] = savec;
    return (result);
}

/*-
 *-----------------------------------------------------------------------
 * CondDoTarget --
 *	See if the given node exists and is an actual target.
 *
 * Results:
 *	TRUE if the node exists as a target and FALSE if it does not.
 *
 * Side Effects:
 *	None.
 *
 *-----------------------------------------------------------------------
 */
static Boolean
CondDoTarget (argLen, arg)
    int	    argLen;
    char    *arg;
{
    char    savec = arg[argLen];
    Boolean result;
    GNode   *gn;

    arg[argLen] = '\0';
    gn = Targ_FindNode(arg, TARG_NOCREATE);
    if ((gn != NILGNODE) && !OP_NOP(gn->type)) {
	result = TRUE;
    } else {
	result = FALSE;
    }
    arg[argLen] = savec;
    return (result);
}


/*-
 *-----------------------------------------------------------------------
 * CondCvtArg --
 *	Convert the given number into a double. If the number begins
 *	with 0x, it is interpreted as a hexadecimal integer
 *	and converted to a double from there. All other strings just have
 *	strtod called on them.
 *
 * Results:
 *	Sets 'value' to double value of string.
 *	Returns true if the string was a valid number, false o.w.
 *
 * Side Effects:
 *	Can change 'value' even if string is not a valid number.
 *	
 *
 *-----------------------------------------------------------------------
 */
static Boolean
CondCvtArg(str, value)
    register char    	*str;
    double		*value;
{
    if ((*str == '0') && (str[1] == 'x')) {
	register long i;

	for (str += 2, i = 0; *str; str++) {
	    int x;
	    if (isdigit((unsigned char) *str))
		x  = *str - '0';
	    else if (isxdigit((unsigned char) *str))
		x = 10 + *str - isupper((unsigned char) *str) ? 'A' : 'a';
	    else
		return FALSE;
	    i = (i << 4) + x;
	}
	*value = (double) i;
	return TRUE;
    }
    else {
	char *eptr;
	*value = strtod(str, &eptr);
	return *eptr == '\0';
    }
}

/*-
 *-----------------------------------------------------------------------
 * CondToken --
 *	Return the next token from the input.
 *
 * Results:
 *	A Token for the next lexical token in the stream.
 *
 * Side Effects:
 *	condPushback will be set back to None if it is used.
 *
 *-----------------------------------------------------------------------
 */
static Token
CondToken(doEval)
    Boolean doEval;
{
    Token	  t;

    if (condPushBack == None) {
	while (*condExpr == ' ' || *condExpr == '\t') {
	    condExpr++;
	}
	switch (*condExpr) {
	    case '(':
		t = LParen;
		condExpr++;
		break;
	    case ')':
		t = RParen;
		condExpr++;
		break;
	    case '|':
		if (condExpr[1] == '|') {
		    condExpr++;
		}
		condExpr++;
		t = Or;
		break;
	    case '&':
		if (condExpr[1] == '&') {
		    condExpr++;
		}
		condExpr++;
		t = And;
		break;
	    case '!':
		t = Not;
		condExpr++;
		break;
	    case '\n':
	    case '\0':
		t = EndOfFile;
		break;
	    case '$': {
		char	*lhs;
		char	*rhs;
		char	*op;
		int	varSpecLen;
		Boolean	doFree;

		/*
		 * Parse the variable spec and skip over it, saving its
		 * value in lhs.
		 */
		t = Err;
		lhs = Var_Parse(condExpr, VAR_CMD, doEval,&varSpecLen,&doFree);
		if (lhs == var_Error) {
		    /*
		     * Even if !doEval, we still report syntax errors, which
		     * is what getting var_Error back with !doEval means.
		     */
		    return(Err);
		}
		condExpr += varSpecLen;

		if (!isspace(*condExpr) && strchr("!=><", *condExpr) == NULL) {
		    Buffer buf;
		    char *cp;

		    buf = Buf_Init(0);

		    for (cp = lhs; *cp; cp++)
			Buf_AddByte(buf, (Byte)*cp);

		    if (doFree)
			free(lhs);

		    for (;*condExpr && !isspace(*condExpr); condExpr++)
			Buf_AddByte(buf, (Byte)*condExpr);

		    Buf_AddByte(buf, (Byte)'\0');
		    lhs = (char *)Buf_GetAll(buf, &varSpecLen);
		    Buf_Destroy(buf, FALSE);

		    doFree = TRUE;
		}

		/*
		 * Skip whitespace to get to the operator
		 */
		while (isspace(*condExpr))
		    condExpr++;

		/*
		 * Make sure the operator is a valid one. If it isn't a
		 * known relational operator, pretend we got a
		 * != 0 comparison.
		 */
		op = condExpr;
		switch (*condExpr) {
		    case '!':
		    case '=':
		    case '<':
		    case '>':
			if (condExpr[1] == '=') {
			    condExpr += 2;
			} else {
			    condExpr += 1;
			}
			break;
		    default:
			op = "!=";
			rhs = "0";

			goto do_compare;
		}
		while (isspace(*condExpr)) {
		    condExpr++;
		}
		if (*condExpr == '\0') {
		    Parse_Error(PARSE_WARNING,
				"Missing right-hand-side of operator");
		    goto error;
		}
		rhs = condExpr;
do_compare:
		if (*rhs == '"') {
		    /*
		     * Doing a string comparison. Only allow == and != for
		     * operators.
		     */
		    char    *string;
		    char    *cp, *cp2;
		    int	    qt;
		    Buffer  buf;

do_string_compare:
		    if (((*op != '!') && (*op != '=')) || (op[1] != '=')) {
			Parse_Error(PARSE_WARNING,
		"String comparison operator should be either == or !=");
			goto error;
		    }

		    buf = Buf_Init(0);
		    qt = *rhs == '"' ? 1 : 0;
		    
		    for (cp = &rhs[qt]; 
			 ((qt && (*cp != '"')) || 
			  (!qt && strchr(" \t)", *cp) == NULL)) && 
			 (*cp != '\0'); cp++) {
			if ((*cp == '\\') && (cp[1] != '\0')) {
			    /*
			     * Backslash escapes things -- skip over next
			     * character, if it exists.
			     */