reader: transform get_bidder into register_bidder

There's a notable duplication across all the read bidder code.

Check the archive magic/state, set the bidder private data (to NULL in
all but one case), name and vtable.

Change the helper to do the actual registration, keeping things simpler
in the dozen+ filters. This also allows us to enforce the bidder ::bid
and ::init dispatch are non NULL. The final one ::free is optional.

NOTE: some of the bidders do _not_ set a name, which I suspect is a
pre-existing bug. I've left them as-is, but we might want to fix and
enforce that somehow.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>

1 files changed, 2 insertions, 8 deletions

diff --git a/libarchive/archive_read_support_filter_lrzip.c b/libarchive/archive_read_support_filter_lrzip.c
index 77dae4b3..a2389894 100644
--- a/libarchive/archive_read_support_filter_lrzip.c
+++ b/libarchive/archive_read_support_filter_lrzip.c
@@ -63,17 +63,11 @@ int
 archive_read_support_filter_lrzip(struct archive *_a)
 {
 	struct archive_read *a = (struct archive_read *)_a;
-	struct archive_read_filter_bidder *reader;
 
-	archive_check_magic(_a, ARCHIVE_READ_MAGIC,
-	    ARCHIVE_STATE_NEW, "archive_read_support_filter_lrzip");
-
-	if (__archive_read_get_bidder(a, &reader) != ARCHIVE_OK)
+	if (__archive_read_register_bidder(a, NULL, "lrzip",
+				&lrzip_bidder_vtable) != ARCHIVE_OK)
 		return (ARCHIVE_FATAL);
 
-	reader->data = NULL;
-	reader->name = "lrzip";
-	reader->vtable = &lrzip_bidder_vtable;
 	/* This filter always uses an external program. */
 	archive_set_error(_a, ARCHIVE_ERRNO_MISC,
 	    "Using external lrzip program for lrzip decompression");