[src/trunk]: src/usr.bin/make make(1): clean up and document VarAssign_Eval

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

details:   https://anonhg.NetBSD.org/src/rev/0bae1e753ad7
branches:  trunk
changeset: 977238:0bae1e753ad7
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sun Oct 18 20:46:42 2020 +0000

description:
make(1): clean up and document VarAssign_Eval

In the previous commit, out_avalue_freeIt had been passed to
VarAssign_EvalSubst, which created a memory leak.  Other than that, the
code changes are purely cosmetic.

diffstat:

 usr.bin/make/parse.c |  43 +++++++++++++++++++++++--------------------
 1 files changed, 23 insertions(+), 20 deletions(-)

diffs (103 lines):

diff -r ecdf2306de7a -r 0bae1e753ad7 usr.bin/make/parse.c
--- a/usr.bin/make/parse.c      Sun Oct 18 20:29:50 2020 +0000
+++ b/usr.bin/make/parse.c      Sun Oct 18 20:46:42 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: parse.c,v 1.390 2020/10/18 20:29:50 rillig Exp $       */
+/*     $NetBSD: parse.c,v 1.391 2020/10/18 20:46:42 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 1.390 2020/10/18 20:29:50 rillig Exp $");
+MAKE_RCSID("$NetBSD: parse.c,v 1.391 2020/10/18 20:46:42 rillig Exp $");
 
 /* types and constants */
 
@@ -1898,11 +1898,9 @@
 }
 
 static void
-VarAssign_EvalSubst(const VarAssign *var, GNode *ctxt,
+VarAssign_EvalSubst(const char *name, const char *uvalue, GNode *ctxt,
                    const char **out_avalue, void **out_avalue_freeIt)
 {
-    const char *name = var->varname;
-    const char *uvalue = var->value;
     const char *avalue = uvalue;
     char *evalue;
     /*
@@ -1938,10 +1936,9 @@
 }
 
 static void
-VarAssign_EvalShell(const VarAssign *var, GNode *ctxt,
+VarAssign_EvalShell(const char *name, const char *uvalue, GNode *ctxt,
                    const char **out_avalue, void **out_avalue_freeIt)
 {
-    const char *uvalue = var->value;
     const char *cmd, *errfmt;
     char *cmdOut;
     void *cmd_freeIt = NULL;
@@ -1955,7 +1952,7 @@
     }
 
     cmdOut = Cmd_Exec(cmd, &errfmt);
-    Var_Set(var->varname, cmdOut, ctxt);
+    Var_Set(name, cmdOut, ctxt);
     *out_avalue = *out_avalue_freeIt = cmdOut;
 
     if (errfmt)
@@ -1964,24 +1961,29 @@
     free(cmd_freeIt);
 }
 
+/* Perform a variable assignment.
+ *
+ * The actual value of the variable is returned in *out_avalue and
+ * *out_avalue_freeIt.  Especially for VAR_SUBST and VAR_SHELL this can differ
+ * from the literal value.
+ *
+ * Return whether the assignment was actually done.  The assignment is only
+ * skipped if the operator is '?=' and the variable already exists. */
 static Boolean
-VarAssign_Eval(VarAssign *var, GNode *ctxt,
-              const char **out_avalue, void **out_avalue_freeIt)
+VarAssign_Eval(const char *name, VarAssignOp op, const char *uvalue,
+              GNode *ctxt, const char **out_avalue, void **out_avalue_freeIt)
 {
-    const char *uvalue = var->value;
-    const char *name = var->varname;
-    const VarAssignOp type = var->op;
     const char *avalue = uvalue;
     void *avalue_freeIt = NULL;
 
-    if (type == VAR_APPEND) {
+    if (op == VAR_APPEND) {
        Var_Append(name, uvalue, ctxt);
-    } else if (type == VAR_SUBST) {
-        VarAssign_EvalSubst(var, ctxt, &avalue, out_avalue_freeIt);
-    } else if (type == VAR_SHELL) {
-        VarAssign_EvalShell(var, ctxt, &avalue, &avalue_freeIt);
+    } else if (op == VAR_SUBST) {
+        VarAssign_EvalSubst(name, uvalue, ctxt, &avalue, &avalue_freeIt);
+    } else if (op == VAR_SHELL) {
+        VarAssign_EvalShell(name, uvalue, ctxt, &avalue, &avalue_freeIt);
     } else {
-       if (type == VAR_DEFAULT && Var_Exists(name, ctxt)) {
+       if (op == VAR_DEFAULT && Var_Exists(name, ctxt)) {
            *out_avalue_freeIt = NULL;
            return FALSE;
        }
@@ -2035,7 +2037,8 @@
     void *avalue_freeIt;
 
     VarCheckSyntax(var->op, var->value, ctxt);
-    if (VarAssign_Eval(var, ctxt, &avalue, &avalue_freeIt))
+    if (VarAssign_Eval(var->varname, var->op, var->value, ctxt,
+                      &avalue, &avalue_freeIt))
        VarAssignSpecial(var->varname, avalue);
 
     free(avalue_freeIt);