remove dead code from the csum-file interface

The provided name argument is always constant and valid in every
caller's context, so no need to have an array of PATH_MAX chars to copy
it into when a simple pointer will do.  Unfortunately that means getting
rid of wascally wabbits too.

The 'error' field is also unused.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

csum-file.c

@@ -88,22 +88,12 @@ struct sha1file *sha1fd(int fd, const char *name)
 
 struct sha1file *sha1fd_throughput(int fd, const char *name, struct progress *tp)
 {
-	struct sha1file *f;
-	unsigned len;
-
-	f = xmalloc(sizeof(*f));
-
-	len = strlen(name);
-	if (len >= PATH_MAX)
-		die("you wascally wabbit, you");
-	f->namelen = len;
-	memcpy(f->name, name, len+1);
-
+	struct sha1file *f = xmalloc(sizeof(*f));
 	f->fd = fd;
-	f->error = 0;
 	f->offset = 0;
 	f->total = 0;
 	f->tp = tp;
+	f->name = name;
 	f->do_crc = 0;
 	SHA1_Init(&f->ctx);
 	return f;

csum-file.h

@@ -5,12 +5,12 @@ struct progress;
 
 /* A SHA1-protected file */
 struct sha1file {
-	int fd, error;
-	unsigned int offset, namelen;
+	int fd;
+	unsigned int offset;
 	SHA_CTX ctx;
 	off_t total;
 	struct progress *tp;
-	char name[PATH_MAX];
+	const char *name;
 	int do_crc;
 	uint32_t crc32;
 	unsigned char buffer[8192];