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

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

details:   https://anonhg.NetBSD.org/src/rev/b06765c0e742
branches:  trunk
changeset: 936855:b06765c0e742
user:      rillig <rillig%NetBSD.org@localhost>
date:      Thu Aug 06 17:32:40 2020 +0000

description:
make(1): clean up code for variable handling

The VarFlags type doesn't need an underscore.  The underscore is
typically only used for exported functions.

Document the memory allocation details for Var.name.

Use consistent names for Hash_Entry variables.  Quite possibly one of
them was a Lst_Node in ancient times, but that's not a reason to keep
this variable name forever.

diffstat:

 usr.bin/make/var.c |  37 ++++++++++++++++++++-----------------
 1 files changed, 20 insertions(+), 17 deletions(-)

diffs (98 lines):

diff -r 73ae2e59ce2c -r b06765c0e742 usr.bin/make/var.c
--- a/usr.bin/make/var.c        Thu Aug 06 17:22:15 2020 +0000
+++ b/usr.bin/make/var.c        Thu Aug 06 17:32:40 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: var.c,v 1.413 2020/08/03 21:44:43 rillig Exp $ */
+/*     $NetBSD: var.c,v 1.414 2020/08/06 17:32:40 rillig Exp $ */
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1993
@@ -69,14 +69,14 @@
  */
 
 #ifndef MAKE_NATIVE
-static char rcsid[] = "$NetBSD: var.c,v 1.413 2020/08/03 21:44:43 rillig Exp $";
+static char rcsid[] = "$NetBSD: var.c,v 1.414 2020/08/06 17:32:40 rillig Exp $";
 #else
 #include <sys/cdefs.h>
 #ifndef lint
 #if 0
 static char sccsid[] = "@(#)var.c      8.3 (Berkeley) 3/19/94";
 #else
-__RCSID("$NetBSD: var.c,v 1.413 2020/08/03 21:44:43 rillig Exp $");
+__RCSID("$NetBSD: var.c,v 1.414 2020/08/06 17:32:40 rillig Exp $");
 #endif
 #endif /* not lint */
 #endif
@@ -216,12 +216,15 @@
     VAR_REEXPORT       = 0x20, /* Indicate if var needs re-export.
                                 * This would be true if it contains $'s */
     VAR_FROM_CMD       = 0x40  /* Variable came from command line */
-} Var_Flags;
+} VarFlags;
 
 typedef struct Var {
-    char          *name;       /* the variable's name */
+    char          *name;       /* the variable's name; it is allocated for
+                                * environment variables and aliased to the
+                                * Hash_Entry name for all other variables,
+                                * and thus must not be modified */
     Buffer       val;          /* its value */
-    Var_Flags    flags;        /* miscellaneous status flags */
+    VarFlags     flags;        /* miscellaneous status flags */
 }  Var;
 
 /*
@@ -420,16 +423,16 @@
     Var *v = bmake_malloc(sizeof(Var));
 
     size_t len = val != NULL ? strlen(val) : 0;
-    Hash_Entry *h;
+    Hash_Entry *he;
 
     Buf_InitZ(&v->val, len + 1);
     Buf_AddBytesZ(&v->val, val, len);
 
     v->flags = 0;
 
-    h = Hash_CreateEntry(&ctxt->context, name, NULL);
-    Hash_SetValue(h, v);
-    v->name = h->name;
+    he = Hash_CreateEntry(&ctxt->context, name, NULL);
+    Hash_SetValue(he, v);
+    v->name = he->name;
     VAR_DEBUG_IF(!(ctxt->flags & INTERNAL),
                 "%s:%s = %s\n", ctxt->name, name, val);
 }
@@ -439,24 +442,24 @@
 Var_Delete(const char *name, GNode *ctxt)
 {
     char *name_freeIt = NULL;
-    Hash_Entry *ln;
+    Hash_Entry *he;
 
     if (strchr(name, '$') != NULL)
        name = name_freeIt = Var_Subst(name, VAR_GLOBAL, VARE_WANTRES);
-    ln = Hash_FindEntry(&ctxt->context, name);
+    he = Hash_FindEntry(&ctxt->context, name);
     VAR_DEBUG("%s:delete %s%s\n",
-             ctxt->name, name, ln != NULL ? "" : " (not found)");
+             ctxt->name, name, he != NULL ? "" : " (not found)");
     free(name_freeIt);
 
-    if (ln != NULL) {
-       Var *v = (Var *)Hash_GetValue(ln);
+    if (he != NULL) {
+       Var *v = (Var *)Hash_GetValue(he);
        if (v->flags & VAR_EXPORTED)
            unsetenv(v->name);
        if (strcmp(MAKE_EXPORTED, v->name) == 0)
            var_exportedVars = VAR_EXPORTED_NONE;
-       if (v->name != ln->name)
+       if (v->name != he->name)
            free(v->name);
-       Hash_DeleteEntry(&ctxt->context, ln);
+       Hash_DeleteEntry(&ctxt->context, he);
        Buf_Destroy(&v->val, TRUE);
        free(v);
     }