index-pack: --verify

Given an existing .pack file and the .idx file that describes it,
this new mode of operation reads and re-index the packfile and makes
sure the existing .idx file matches the result byte-for-byte.

All the objects in the .pack file are validated during this operation as
well.  Unlike verify-pack, which visits each object described in the .idx
file in the SHA-1 order, index-pack efficiently exploits the delta-chain
to avoid rebuilding the objects that are used as the base of deltified
objects over and over again while validating the objects, resulting in
much quicker verification of the .pack file and its .idx file.

This version however cannot verify a .pack/.idx pair with a handcrafted v2
index that uses 64-bit offset representation for offsets that would fit
within 31-bit. You can create such an .idx file by giving a custom offset
to --index-version option to the command.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/csum-file.h b/csum-file.h
index 294add2..6a7967c 100644
--- a/csum-file.h
+++ b/csum-file.h
@@ -6,6 +6,7 @@ struct progress;
 /* A SHA1-protected file */
 struct sha1file {
 	int fd;
+	int check_fd;
 	unsigned int offset;
 	git_SHA_CTX ctx;
 	off_t total;
@@ -21,6 +22,7 @@ struct sha1file {
 #define CSUM_FSYNC	2
 
 extern struct sha1file *sha1fd(int fd, const char *name);
+extern struct sha1file *sha1fd_check(const char *name);
 extern struct sha1file *sha1fd_throughput(int fd, const char *name, struct progress *tp);
 extern int sha1close(struct sha1file *, unsigned char *, unsigned int);
 extern int sha1write(struct sha1file *, void *, unsigned int);