Wed Jan 3 20:24:16 2024 UTC (151d)

make: do not add newline to an empty buffer

When LoadFile reads from /dev/null the buffer will be empty,
appending "\n" just results in an unnecessary extra call
to ParseRawLine.

Reviewed by: rillig


(sjg)

diff -r1.713 -r1.714 src/usr.bin/make/parse.c

--- src/usr.bin/make/parse.c 2023/12/29 20:43:58	1.713
+++ src/usr.bin/make/parse.c 2024/01/03 20:24:16	1.714

 @@ -1,14 +1,14 @@
-/*	$NetBSD: parse.c,v 1.713 2023/12/29 20:43:58 rillig Exp $	*/
+/*	$NetBSD: parse.c,v 1.714 2024/01/03 20:24:16 sjg Exp $	*/
 /*
  * Copyright (c) 1988, 1989, 1990, 1993
  *	The Regents of the University of California.  All rights reserved.
+ *
  * This code is derived from software contributed to Berkeley by
  * Adam de Boor.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
 @@ -95,27 +95,27 @@
  */
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <errno.h>
 #include <stdarg.h>
 #include "make.h"
 #include "dir.h"
 #include "job.h"
 #include "pathnames.h"
 /*	"@(#)parse.c	8.3 (Berkeley) 3/19/94"	*/
-MAKE_RCSID("$NetBSD: parse.c,v 1.713 2023/12/29 20:43:58 rillig Exp $");
+MAKE_RCSID("$NetBSD: parse.c,v 1.714 2024/01/03 20:24:16 sjg Exp $");
 /* Detects a multiple-inclusion guard in a makefile. */
 typedef enum {
 	GS_START,		/* at the beginning of the file */
 	GS_COND,		/* after the guard condition */
 	GS_DONE,		/* after the closing .endif */
 	GS_NO			/* the file is not guarded */
 } GuardState;
 /*
  * A file being read.
  */
 typedef struct IncludedFile {
 @@ -373,27 +373,27 @@ LoadFile(const char *path, int fd)
 		assert(buf.len < buf.cap);
 		n = read(fd, buf.data + buf.len, buf.cap - buf.len);
 		if (n < 0) {
 			Error("%s: read error: %s", path, strerror(errno));
 			exit(2);	/* Not 1 so -q can distinguish error */
+		}
 		if (n == 0)
 			break;
 		buf.len += (size_t)n;
+	}
 	assert(buf.len <= buf.cap);
-	if (!Buf_EndsWith(&buf, '\n'))
+	if (buf.len > 0 && !Buf_EndsWith(&buf, '\n'))
 		Buf_AddByte(&buf, '\n');
 	return buf;		/* may not be null-terminated */
+}
 /*
  * Print the current chain of .include and .for directives.  In Parse_Fatal
  * or other functions that already print the location, includingInnermost
  * would be redundant, but in other cases like Error or Fatal it needs to be
  * included.
  */
 void
 PrintStackTrace(bool includingInnermost)