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git/pack-check.c
Nicolas Pitre d60fc1c864 remove delta-against-self bit
After experimenting with code to add the ability to encode a delta
against part of the deltified file, it turns out that resulting packs
are _bigger_ than when this ability is not used.  The raw delta output
might be smaller, but it doesn't compress as well using gzip with a
negative net saving on average.

Said bit would in fact be more useful to allow for encoding the copying
of chunks larger than 64KB providing more savings with large files.
This will correspond to packs version 3.

While the current code still produces packs version 2, it is made future
proof so pack versions 2 and 3 are accepted.  Any pack version 2 are
compatible with version 3 since the redefined bit was never used before.
When enough time has passed, code to use that bit to produce version 3
packs could be added.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-02-09 21:06:38 -08:00

143 lines
3.7 KiB
C

#include "cache.h"
#include "pack.h"
static int verify_packfile(struct packed_git *p)
{
unsigned long index_size = p->index_size;
void *index_base = p->index_base;
SHA_CTX ctx;
unsigned char sha1[20];
unsigned long pack_size = p->pack_size;
void *pack_base;
struct pack_header *hdr;
int nr_objects, err, i;
/* Header consistency check */
hdr = p->pack_base;
if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
return error("Packfile %s signature mismatch", p->pack_name);
if (!pack_version_ok(hdr->hdr_version))
return error("Packfile version %d unsupported",
ntohl(hdr->hdr_version));
nr_objects = ntohl(hdr->hdr_entries);
if (num_packed_objects(p) != nr_objects)
return error("Packfile claims to have %d objects, "
"while idx size expects %d", nr_objects,
num_packed_objects(p));
SHA1_Init(&ctx);
pack_base = p->pack_base;
SHA1_Update(&ctx, pack_base, pack_size - 20);
SHA1_Final(sha1, &ctx);
if (memcmp(sha1, index_base + index_size - 40, 20))
return error("Packfile %s SHA1 mismatch with idx",
p->pack_name);
if (memcmp(sha1, pack_base + pack_size - 20, 20))
return error("Packfile %s SHA1 mismatch with itself",
p->pack_name);
/* Make sure everything reachable from idx is valid. Since we
* have verified that nr_objects matches between idx and pack,
* we do not do scan-streaming check on the pack file.
*/
for (i = err = 0; i < nr_objects; i++) {
unsigned char sha1[20];
struct pack_entry e;
void *data;
char type[20];
unsigned long size;
if (nth_packed_object_sha1(p, i, sha1))
die("internal error pack-check nth-packed-object");
if (!find_pack_entry_one(sha1, &e, p))
die("internal error pack-check find-pack-entry-one");
data = unpack_entry_gently(&e, type, &size);
if (!data) {
err = error("cannot unpack %s from %s",
sha1_to_hex(sha1), p->pack_name);
continue;
}
if (check_sha1_signature(sha1, data, size, type)) {
err = error("packed %s from %s is corrupt",
sha1_to_hex(sha1), p->pack_name);
free(data);
continue;
}
free(data);
}
return err;
}
static void show_pack_info(struct packed_git *p)
{
struct pack_header *hdr;
int nr_objects, i;
hdr = p->pack_base;
nr_objects = ntohl(hdr->hdr_entries);
for (i = 0; i < nr_objects; i++) {
unsigned char sha1[20], base_sha1[20];
struct pack_entry e;
char type[20];
unsigned long size;
unsigned long store_size;
int delta_chain_length;
if (nth_packed_object_sha1(p, i, sha1))
die("internal error pack-check nth-packed-object");
if (!find_pack_entry_one(sha1, &e, p))
die("internal error pack-check find-pack-entry-one");
packed_object_info_detail(&e, type, &size, &store_size,
&delta_chain_length,
base_sha1);
printf("%s ", sha1_to_hex(sha1));
if (!delta_chain_length)
printf("%-6s %lu %u\n", type, size, e.offset);
else
printf("%-6s %lu %u %d %s\n", type, size, e.offset,
delta_chain_length, sha1_to_hex(base_sha1));
}
}
int verify_pack(struct packed_git *p, int verbose)
{
unsigned long index_size = p->index_size;
void *index_base = p->index_base;
SHA_CTX ctx;
unsigned char sha1[20];
int ret;
ret = 0;
/* Verify SHA1 sum of the index file */
SHA1_Init(&ctx);
SHA1_Update(&ctx, index_base, index_size - 20);
SHA1_Final(sha1, &ctx);
if (memcmp(sha1, index_base + index_size - 20, 20))
ret = error("Packfile index for %s SHA1 mismatch",
p->pack_name);
if (!ret) {
/* Verify pack file */
use_packed_git(p);
ret = verify_packfile(p);
unuse_packed_git(p);
}
if (verbose) {
if (ret)
printf("%s: bad\n", p->pack_name);
else {
use_packed_git(p);
show_pack_info(p);
unuse_packed_git(p);
printf("%s: ok\n", p->pack_name);
}
}
return ret;
}