[src/trunk]: src/usr.bin/make make(1): clean up code for parsing ?= variable ...

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

details:   https://anonhg.NetBSD.org/src/rev/1376f5c7c046
branches:  trunk
changeset: 955601:1376f5c7c046
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sun Oct 04 20:37:11 2020 +0000

description:
make(1): clean up code for parsing ?= variable assignments

There is no need to handle the ?= operator in ParseVarassignOp already,
when all other operators are handled later.

diffstat:

 usr.bin/make/parse.c |  53 ++++++++++++++++++++-------------------------------
 1 files changed, 21 insertions(+), 32 deletions(-)

diffs (135 lines):

diff -r c96a9958a287 -r 1376f5c7c046 usr.bin/make/parse.c
--- a/usr.bin/make/parse.c      Sun Oct 04 20:36:32 2020 +0000
+++ b/usr.bin/make/parse.c      Sun Oct 04 20:37:11 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: parse.c,v 1.357 2020/10/04 20:23:32 rillig Exp $       */
+/*     $NetBSD: parse.c,v 1.358 2020/10/04 20:37:11 rillig Exp $       */
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1993
@@ -131,7 +131,7 @@
 #include "pathnames.h"
 
 /*     "@(#)parse.c    8.3 (Berkeley) 3/19/94" */
-MAKE_RCSID("$NetBSD: parse.c,v 1.357 2020/10/04 20:23:32 rillig Exp $");
+MAKE_RCSID("$NetBSD: parse.c,v 1.358 2020/10/04 20:37:11 rillig Exp $");
 
 /* types and constants */
 
@@ -1743,48 +1743,37 @@
 
 /* Determine the assignment operator and adjust the end of the variable
  * name accordingly. */
-static Boolean
+static void
 ParseVarassignOp(VarAssign *var, const char **out_op, GNode *ctxt)
 {
     const char *op = var->eq;
-    const char * const nameStart = var->nameStart;
+    const char * const name = var->nameStart;
     VarAssignOp type;
 
     var->varname = NULL;
-    if (op > nameStart && op[-1] == '+') {
+    if (op > name && op[-1] == '+') {
        type = VAR_APPEND;
        op--;
 
-    } else if (op > nameStart && op[-1] == '?') {
-       /* If the variable already has a value, we don't do anything. */
-       Boolean exists;
-       const char *nameEnd;
+    } else if (op > name && op[-1] == '?') {
+        op--;
+        type = VAR_DEFAULT;
 
-       op--;
-       nameEnd = var->nameEndDraft < op ? var->nameEndDraft : op;
-       var->varname = bmake_strsedup(nameStart, nameEnd);
-       exists = Var_Exists(var->varname, ctxt);
-       if (exists) {
-           free(var->varname);
-           return FALSE;
-       }
-       type = VAR_NORMAL;
-
-    } else if (op > nameStart && op[-1] == ':') {
+    } else if (op > name && op[-1] == ':') {
        op--;
        type = VAR_SUBST;
 
-    } else if (op > nameStart && op[-1] == '!') {
+    } else if (op > name && op[-1] == '!') {
        op--;
        type = VAR_SHELL;
 
     } else {
        type = VAR_NORMAL;
 #ifdef SUNSHCMD
-       while (op > nameStart && ch_isspace(op[-1]))
+       while (op > name && ch_isspace(op[-1]))
            op--;
 
-       if (op >= nameStart + 3 && op[-3] == ':' && op[-2] == 's' && op[-1] == 'h') {
+       if (op >= name + 3 && op[-3] == ':' && op[-2] == 's' && op[-1] == 'h') {
            type = VAR_SHELL;
            op -= 3;
        }
@@ -1793,7 +1782,6 @@
 
     *out_op = op;
     var->op = type;
-    return TRUE;
 }
 
 static void
@@ -1812,7 +1800,7 @@
     }
 }
 
-static void
+static Boolean
 VarAssign_Eval(VarAssign *var,
          const char *const uvalue, const char **out_avalue, char **out_evalue,
          GNode *ctxt)
@@ -1875,14 +1863,16 @@
        if (error)
            Parse_Error(PARSE_WARNING, error, avalue);
     } else {
-       /*
-        * Normal assignment -- just do it.
-        */
+       if (type == VAR_DEFAULT && Var_Exists(var->varname, ctxt))
+           return FALSE;
+
+       /* Normal assignment -- just do it. */
        Var_Set(name, uvalue, ctxt);
     }
 
     *out_avalue = avalue;
     *out_evalue = evalue;
+    return TRUE;
 }
 
 static void
@@ -1934,8 +1924,7 @@
      * actual end of the variable name. */
     const char *op;
 
-    if (!ParseVarassignOp(var, &op, ctxt))
-       return;
+    ParseVarassignOp(var, &op, ctxt);
 
     uvalue = var->value;
     avalue = uvalue;
@@ -1947,8 +1936,8 @@
        var->varname = bmake_strsedup(var->nameStart, nameEnd);
     }
 
-    VarAssign_Eval(var, uvalue, &avalue, &evalue, ctxt);
-    VarAssignSpecial(var->varname, avalue);
+    if (VarAssign_Eval(var, uvalue, &avalue, &evalue, ctxt))
+       VarAssignSpecial(var->varname, avalue);
 
     free(evalue);
     free(var->varname);