[src/trunk]: src/usr.bin/make make: restructure code in ParseVarname to targe...

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

details:   https://anonhg.NetBSD.org/src/rev/9a6f5b2e1dd7
branches:  trunk
changeset: 980981:9a6f5b2e1dd7
user:      rillig <rillig%NetBSD.org@localhost>
date:      Tue Feb 23 16:14:11 2021 +0000

description:
make: restructure code in ParseVarname to target human readers

Breaking the loop once for depth == 0 and once for depth == 1 was
unnecessarily confusing, as was the nested 'if'.  Start counting with 0
since there is no reason to start at 1.

Evaluating the common subexpression '*p == endc' is left as an exercise
to the compiler.

No functional change.

diffstat:

 usr.bin/make/var.c |  17 +++++++----------
 1 files changed, 7 insertions(+), 10 deletions(-)

diffs (44 lines):

diff -r cefcc6091544 -r 9a6f5b2e1dd7 usr.bin/make/var.c
--- a/usr.bin/make/var.c        Tue Feb 23 16:07:14 2021 +0000
+++ b/usr.bin/make/var.c        Tue Feb 23 16:14:11 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: var.c,v 1.853 2021/02/23 16:07:14 rillig Exp $ */
+/*     $NetBSD: var.c,v 1.854 2021/02/23 16:14:11 rillig Exp $ */
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1993
@@ -140,7 +140,7 @@
 #include "metachar.h"
 
 /*     "@(#)var.c      8.3 (Berkeley) 3/19/94" */
-MAKE_RCSID("$NetBSD: var.c,v 1.853 2021/02/23 16:07:14 rillig Exp $");
+MAKE_RCSID("$NetBSD: var.c,v 1.854 2021/02/23 16:14:11 rillig Exp $");
 
 typedef enum VarFlags {
        VFL_NONE        = 0,
@@ -3900,20 +3900,17 @@
 {
        Buffer buf;
        const char *p = *pp;
-       int depth = 1;
+       int depth = 0;          /* Track depth so we can spot parse errors. */
 
        Buf_Init(&buf);
 
        while (*p != '\0') {
-               /* Track depth so we can spot parse errors. */
+               if ((*p == endc || *p == ':') && depth == 0)
+                       break;
                if (*p == startc)
                        depth++;
-               if (*p == endc) {
-                       if (--depth == 0)
-                               break;
-               }
-               if (*p == ':' && depth == 1)
-                       break;
+               if (*p == endc)
+                       depth--;
 
                /* A variable inside a variable, expand. */
                if (*p == '$') {