[src/trunk]: src/usr.bin/make make(1): extract ArchiveMember_HasName from Arc...

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

details:   https://anonhg.NetBSD.org/src/rev/461731e4a127
branches:  trunk
changeset: 977976:461731e4a127
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sat Nov 07 12:34:49 2020 +0000

description:
make(1): extract ArchiveMember_HasName from ArchFindMember

Comparing a string to a space-padded string is complicated enough to be
extracted to a separate function.

The behavior changes a little bit.  Before, when searching for an archive
member with a short name (one that is space-padded in the archive), that
member was not searched using the AR_EFMT1 archive format.  This doesn't
matter in practice though since no regular archive member has a name
starting with "#1/".

diffstat:

 usr.bin/make/arch.c |  44 +++++++++++++++++++++++---------------------
 1 files changed, 23 insertions(+), 21 deletions(-)

diffs (90 lines):

diff -r 802440cd7aef -r 461731e4a127 usr.bin/make/arch.c
--- a/usr.bin/make/arch.c       Sat Nov 07 11:36:49 2020 +0000
+++ b/usr.bin/make/arch.c       Sat Nov 07 12:34:49 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: arch.c,v 1.157 2020/11/07 11:36:49 rillig Exp $        */
+/*     $NetBSD: arch.c,v 1.158 2020/11/07 12:34:49 rillig Exp $        */
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1993
@@ -125,7 +125,7 @@
 #include "config.h"
 
 /*     "@(#)arch.c     8.2 (Berkeley) 1/2/94"  */
-MAKE_RCSID("$NetBSD: arch.c,v 1.157 2020/11/07 11:36:49 rillig Exp $");
+MAKE_RCSID("$NetBSD: arch.c,v 1.158 2020/11/07 12:34:49 rillig Exp $");
 
 #ifdef TARGET_MACHINE
 #undef MAKE_MACHINE
@@ -675,6 +675,23 @@
 #endif
 
 
+static Boolean
+ArchiveMember_HasName(const struct ar_hdr *hdr,
+                     const char *name, size_t namelen)
+{
+    const size_t ar_name_len = sizeof hdr->ar_name;
+    const char *ar_name = hdr->ar_name;
+
+    if (strncmp(ar_name, name, namelen) != 0)
+       return FALSE;
+
+    if (namelen >= ar_name_len)
+       return namelen == ar_name_len;
+
+    /* hdr->ar_name is space-padded to the right. */
+    return ar_name[namelen] == ' ';
+}
+
 /* Locate a member of an archive, given the path of the archive and the path
  * of the desired member.
  *
@@ -739,24 +756,14 @@
            return NULL;
        }
 
-       if (strncmp(member, out_arh->ar_name, tlen) == 0) {
+       if (ArchiveMember_HasName(out_arh, member, len)) {
            /*
-            * If the member's name doesn't take up the entire 'name' field,
-            * we have to be careful of matching prefixes. Names are space-
-            * padded to the right, so if the character in 'name' at the end
-            * of the matched string is anything but a space, this isn't the
-            * member we sought.
-            */
-           if (tlen != sizeof out_arh->ar_name &&
-               out_arh->ar_name[tlen] != ' ')
-               goto skip;
-
-           /*
-            * To make life easier, we reposition the file at the start
+            * To make life easier for callers that want to update the
+            * archive, we reposition the file at the start
             * of the header we just read before we return the stream.
             * In a more general situation, it might be better to leave
             * the file at the actual member, rather than its header, but
-            * not here...
+            * not here.
             */
            if (fseek(arch, -(long)sizeof *out_arh, SEEK_CUR) != 0) {
                fclose(arch);
@@ -804,7 +811,6 @@
        }
 #endif
 
-skip:
        /*
         * This isn't the member we're after, so we need to advance the
         * stream's pointer to the start of the next header. Files are
@@ -820,10 +826,6 @@
        }
     }
 
-    /*
-     * We've looked everywhere, but the member is not to be found. Close the
-     * archive and return NULL -- an error.
-     */
     fclose(arch);
     return NULL;
 }