git-tar-tree: Simplify write_trailer()

We can write the trailer in one or at most two steps; it will always
fit within two blocks.  With the last caller of get_record() gone we
can get rid of it.

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <junkio@cox.net>

builtin-tar-tree.c

@@ -47,31 +47,6 @@ static void write_if_needed(void)
 	}
 }
 
-/* acquire the next record from the buffer; user must call write_if_needed() */
-static char *get_record(void)
-{
-	char *p = block + offset;
-	memset(p, 0, RECORDSIZE);
-	offset += RECORDSIZE;
-	return p;
-}
-
-/*
- * The end of tar archives is marked by 1024 nul bytes and after that
- * follows the rest of the block (if any).
- */
-static void write_trailer(void)
-{
-	get_record();
-	write_if_needed();
-	get_record();
-	write_if_needed();
-	while (offset) {
-		get_record();
-		write_if_needed();
-	}
-}
-
 /*
  * queues up writes, so that all our write(2) calls write exactly one
  * full block; pads writes to RECORDSIZE
@@ -107,6 +82,21 @@ static void write_blocked(void *buf, unsigned long size)
 	write_if_needed();
 }
 
+/*
+ * The end of tar archives is marked by 2*512 nul bytes and after that
+ * follows the rest of the block (if any).
+ */
+static void write_trailer(void)
+{
+	int tail = BLOCKSIZE - offset;
+	memset(block + offset, 0, tail);
+	reliable_write(block, BLOCKSIZE);
+	if (tail < 2 * RECORDSIZE) {
+		memset(block, 0, offset);
+		reliable_write(block, BLOCKSIZE);
+	}
+}
+
 static void strbuf_append_string(struct strbuf *sb, const char *s)
 {
 	int slen = strlen(s);