[src/trunk]: src/usr.bin/make make: make ParseWord in condition parser simpler

[rillig <rillig%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/e4ad3fc96194
branches:  trunk
changeset: 1029283:e4ad3fc96194
user:      rillig <rillig%NetBSD.org@localhost>
date:      Thu Dec 30 01:06:43 2021 +0000

description:
make: make ParseWord in condition parser simpler

Merge the two return values (bool, string) into a single return value.
As before, the caller cannot observe the difference between a parse
error and an empty word, both are handled in the same way.

In CondParser_ComparisonOrLeaf, the word cannot be empty since the
calling function CondParser_Token already handles all cases that could
lead to an empty word.

No functional change.

diffstat:

 usr.bin/make/cond.c |  39 ++++++++++++++++++++++-----------------
 1 files changed, 22 insertions(+), 17 deletions(-)

diffs (104 lines):

diff -r deba321e0d54 -r e4ad3fc96194 usr.bin/make/cond.c
--- a/usr.bin/make/cond.c       Thu Dec 30 00:22:20 2021 +0000
+++ b/usr.bin/make/cond.c       Thu Dec 30 01:06:43 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: cond.c,v 1.317 2021/12/30 00:22:20 rillig Exp $        */
+/*     $NetBSD: cond.c,v 1.318 2021/12/30 01:06:43 rillig Exp $        */
 
 /*
  * Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
@@ -95,7 +95,7 @@
 #include "dir.h"
 
 /*     "@(#)cond.c     8.2 (Berkeley) 1/2/94"  */
-MAKE_RCSID("$NetBSD: cond.c,v 1.317 2021/12/30 00:22:20 rillig Exp $");
+MAKE_RCSID("$NetBSD: cond.c,v 1.318 2021/12/30 01:06:43 rillig Exp $");
 
 /*
  * The parsing of conditional expressions is based on this grammar:
@@ -218,16 +218,15 @@
  *     func says whether the argument belongs to an actual function, or
  *     NULL when parsing a bare word.
  *
- * Return false if there was a parse error or the argument was empty.
+ * Return NULL if there was a parse error or the argument was empty.
  */
-static bool
-ParseWord(CondParser *par, const char **pp, bool doEval, const char *func,
-            char **out_arg)
+static char *
+ParseWord(CondParser *par, const char **pp, bool doEval, const char *func)
 {
        const char *p = *pp;
        Buffer argBuf;
        int paren_depth;
-       bool ok;
+       char *res;
 
        if (func != NULL)
                p++;            /* Skip opening '(' - verified by caller */
@@ -270,8 +269,7 @@
                p++;
        }
 
-       ok = argBuf.len > 0;
-       *out_arg = Buf_DoneData(&argBuf);
+       res = Buf_DoneData(&argBuf);
 
        cpp_skip_hspace(&p);
 
@@ -283,11 +281,17 @@
                Parse_Error(PARSE_FATAL,
                    "Missing closing parenthesis for %.*s()", len, func);
                par->printedError = true;
-               return false;
+               free(res);
+               return NULL;
        }
 
        *pp = p;
-       return ok;
+
+       if (res[0] == '\0') {
+               free(res);
+               res = NULL;
+       }
+       return res;
 }
 
 /* Test whether the given variable is defined. */
@@ -738,8 +742,7 @@
 static bool
 CondParser_FuncCall(CondParser *par, bool doEval, Token *out_token)
 {
-       char *arg = NULL;
-       bool ok;
+       char *arg;
        const char *p = par->p;
        bool (*fn)(const char *);
        const char *fn_name = p;
@@ -761,10 +764,10 @@
        if (*p != '(')
                return false;
 
-       ok = ParseWord(par, &p, doEval, fn_name, &arg);
-       *out_token = ToToken(ok && doEval && fn(arg));
+       arg = ParseWord(par, &p, doEval, fn_name);
+       *out_token = ToToken(doEval && arg != NULL && fn(arg));
+       free(arg);
 
-       free(arg);
        par->p = p;
        return true;
 }
@@ -801,7 +804,9 @@
         * XXX: Is it possible to have a variable expression evaluated twice
         *  at this point?
         */
-       (void)ParseWord(par, &cp, doEval, NULL, &arg);
+       arg = ParseWord(par, &cp, doEval, NULL);
+       assert(arg != NULL);
+
        cp1 = cp;
        cpp_skip_whitespace(&cp1);
        if (*cp1 == '=' || *cp1 == '!' || *cp1 == '<' || *cp1 == '>')