[PATCH] Finish initial cut of git-pack-object/git-unpack-object pair.

This finishes the initial round of git-pack-object /
git-unpack-object pair.  They are now good enough to be used as
a transport medium:

 - Fix delta direction in pack-objects; the original was
   computing delta to create the base object from the object to
   be squashed, which was quite unfriendly for unpacker ;-).

 - Add a script to test the very basics.

 - Implement unpacker for both regular and deltified objects.

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Junio C Hamano 2005-06-26 04:29:18 -07:00 committed by Linus Torvalds
parent d116a45a9a
commit 8ee378a0f0
3 changed files with 261 additions and 18 deletions

View file

@ -82,7 +82,8 @@ static void *delta_against(void *buf, unsigned long size, struct object_entry *e
if (!otherbuf) if (!otherbuf)
die("unable to read %s", sha1_to_hex(entry->delta->sha1)); die("unable to read %s", sha1_to_hex(entry->delta->sha1));
delta_buf = diff_delta(buf, size, otherbuf, othersize, &delta_size, ~0UL); delta_buf = diff_delta(otherbuf, othersize,
buf, size, &delta_size, ~0UL);
if (!delta_buf || delta_size != entry->delta_size) if (!delta_buf || delta_size != entry->delta_size)
die("delta size changed"); die("delta size changed");
free(buf); free(buf);
@ -318,7 +319,8 @@ static int try_delta(struct unpacked *cur, struct unpacked *old, unsigned max_de
max_size = size / 2 - 20; max_size = size / 2 - 20;
if (cur_entry->delta) if (cur_entry->delta)
max_size = cur_entry->delta_size-1; max_size = cur_entry->delta_size-1;
delta_buf = diff_delta(cur->data, size, old->data, oldsize, &delta_size, max_size); delta_buf = diff_delta(old->data, oldsize,
cur->data, size, &delta_size, max_size);
if (!delta_buf) if (!delta_buf)
return 0; return 0;
cur_entry->delta = old_entry; cur_entry->delta = old_entry;

85
t/t5300-pack-object.sh Executable file
View file

@ -0,0 +1,85 @@
#!/bin/sh
#
# Copyright (c) 2005 Junio C Hamano
#
test_description='git-pack-object
'
. ./test-lib.sh
TRASH=`pwd`
test_expect_success \
'setup' \
'rm -f .git/index*
for i in a b c
do
dd if=/dev/zero bs=4k count=1 | tr "\\0" $i >$i &&
git-update-cache --add $i || exit
done &&
cat c >d && echo foo >>d && git-update-cache --add d &&
tree=`git-write-tree` && {
echo $tree &&
git-ls-tree $tree | sed -e "s/.* \\([0-9a-f]*\\) .*/\\1/"
} >obj-list'
test_expect_success \
'pack without delta' \
'git-pack-objects --window=0 test-1 <obj-list'
rm -fr .git2
mkdir .git2
test_expect_success \
'unpack without delta' \
'GIT_OBJECT_DIRECTORY=.git2/objects &&
export GIT_OBJECT_DIRECTORY &&
git-init-db &&
git-unpack-objects test-1'
unset GIT_OBJECT_DIRECTORY
cd $TRASH/.git2
test_expect_success \
'check unpack without delta' \
'(cd ../.git && find objects -type f -print) |
while read path
do
cmp $path ../.git/$path || {
echo $path differs.
exit 1
}
done'
cd $TRASH
test_expect_success \
'pack with delta' \
'pwd &&
git-pack-objects test-2 <obj-list'
rm -fr .git2
mkdir .git2
test_expect_success \
'unpack with delta' \
'GIT_OBJECT_DIRECTORY=.git2/objects &&
export GIT_OBJECT_DIRECTORY &&
git-init-db &&
git-unpack-objects test-2'
unset GIT_OBJECT_DIRECTORY
cd $TRASH/.git2
test_expect_success \
'check unpack with delta' \
'(cd ../.git && find objects -type f -print) |
while read path
do
cmp $path ../.git/$path || {
echo $path differs.
exit 1
}
done'
cd $TRASH
test_done

View file

@ -1,5 +1,6 @@
#include "cache.h" #include "cache.h"
#include "object.h" #include "object.h"
#include "delta.h"
static int dry_run; static int dry_run;
static int nr_entries; static int nr_entries;
@ -7,12 +8,14 @@ static const char *base_name;
static const char unpack_usage[] = "git-unpack-objects basename"; static const char unpack_usage[] = "git-unpack-objects basename";
struct pack_entry { struct pack_entry {
unsigned int offset; unsigned int offset; /* network byte order */
unsigned char sha1[20]; unsigned char sha1[20];
}; };
static void *pack_base; static void *pack_base;
static unsigned long pack_size; static unsigned long pack_size;
static void *index_base;
static unsigned long index_size;
static struct pack_entry **pack_list; static struct pack_entry **pack_list;
@ -52,13 +55,13 @@ static int sort_by_offset(const void *_a, const void *_b)
return o1 < o2 ? -1 : 1; return o1 < o2 ? -1 : 1;
} }
static int check_index(void *index, unsigned long idx_size) static int check_index(void)
{ {
unsigned int *array = index; unsigned int *array = index_base;
unsigned int nr; unsigned int nr;
int i; int i;
if (idx_size < 4*256) if (index_size < 4*256)
return error("index file too small"); return error("index file too small");
nr = 0; nr = 0;
for (i = 0; i < 256; i++) { for (i = 0; i < 256; i++) {
@ -67,15 +70,16 @@ static int check_index(void *index, unsigned long idx_size)
return error("non-monotonic index"); return error("non-monotonic index");
nr = n; nr = n;
} }
if (idx_size != 4*256 + nr * 24) { if (index_size != 4*256 + nr * 24) {
printf("idx_size=%lu, expected %u (%u)\n", idx_size, 4*256 + nr * 24, nr); printf("index_size=%lu, expected %u (%u)\n",
index_size, 4*256 + nr * 24, nr);
return error("wrong index file size"); return error("wrong index file size");
} }
nr_entries = nr; nr_entries = nr;
pack_list = xmalloc(nr * sizeof(struct pack_entry *)); pack_list = xmalloc(nr * sizeof(struct pack_entry *));
for (i = 0; i < nr; i++) for (i = 0; i < nr; i++)
pack_list[i] = index + 4*256 + i*24; pack_list[i] = index_base + 4*256 + i*24;
qsort(pack_list, nr, sizeof(*pack_list), sort_by_offset); qsort(pack_list, nr, sizeof(*pack_list), sort_by_offset);
@ -83,9 +87,165 @@ static int check_index(void *index, unsigned long idx_size)
return 0; return 0;
} }
static int unpack_non_delta_entry(struct pack_entry *entry,
unsigned char *pack)
{
int st, kind;
unsigned long size;
z_stream stream;
char *buffer;
unsigned char sha1[20];
char *type_s;
unsigned long offset = ntohl(entry->offset);
kind = pack[0];
size = (pack[1] << 24) + (pack[2] << 16) + (pack[3] << 8) + pack[4];
printf("%s %c %lu\n", sha1_to_hex(entry->sha1), kind, size);
pack += 5;
buffer = xmalloc(size + 1);
buffer[size] = 0;
memset(&stream, 0, sizeof(stream));
stream.next_in = pack;
stream.avail_in = pack_size - offset; /* sheesh. */
stream.next_out = buffer;
stream.avail_out = size;
inflateInit(&stream);
st = inflate(&stream, Z_FINISH);
inflateEnd(&stream);
if ((st != Z_STREAM_END) || stream.total_out != size)
goto err_finish;
switch (kind) {
case 'C': type_s = "commit"; break;
case 'T': type_s = "tree"; break;
case 'B': type_s = "blob"; break;
default: goto err_finish;
}
if (write_sha1_file(buffer, size, type_s, sha1) < 0)
die("failed to write %s (%s)",
sha1_to_hex(entry->sha1), type_s);
printf("%s %s\n", sha1_to_hex(sha1), type_s);
if (memcmp(sha1, entry->sha1, 20))
die("resulting %s have wrong SHA1", type_s);
finish:
st = 0;
free(buffer);
return st;
err_finish:
st = -1;
goto finish;
}
static int find_pack_entry(unsigned char *sha1, struct pack_entry **ent)
{
int *level1_ofs = index_base;
int hi = ntohl(level1_ofs[*sha1]);
int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
void *index = index_base + 4*256;
do {
int mi = (lo + hi) / 2;
int cmp = memcmp(index + 24 * mi + 4, sha1, 20);
if (!cmp) {
*ent = index + 24 * mi;
return 1;
}
if (cmp < 0)
hi = mi;
else
lo = mi;
} while (lo < hi);
return 0;
}
/* forward declaration for a mutually recursive function */
static void unpack_entry(struct pack_entry *);
static int unpack_delta_entry(struct pack_entry *entry, unsigned char *pack)
{
void *delta_data, *result, *base;
unsigned long delta_alloc, delta_size, result_size, base_size;
z_stream stream;
int st;
char type[20];
unsigned char sha1[20];
printf("%s D", sha1_to_hex(entry->sha1));
printf(" %s\n", sha1_to_hex(pack+1));
/* pack+1 is the base sha1, unless we have it, we need to
* unpack it first.
*/
if (!has_sha1_file(pack+1)) {
struct pack_entry *base;
if (!find_pack_entry(pack+1, &base))
die("cannot find delta-pack base object");
unpack_entry(base);
}
/* pack+1 thru pack+20 is the base sha1 and
* pack+21 thru unknown number is the delta data.
* we do not even have size of the delta data uncompressed.
* sheesh!
*/
delta_alloc = 1024;
delta_data = xmalloc(delta_alloc);
memset(&stream, 0, sizeof(stream));
stream.next_in = pack + 21;
stream.avail_in = pack_size - ntohl(entry->offset); /* sheesh. */
stream.next_out = delta_data;
stream.avail_out = delta_alloc;
delta_size = 0;
inflateInit(&stream);
while (1) {
st = inflate(&stream, Z_FINISH);
if (st == Z_STREAM_END) {
delta_size = stream.total_out;
break;
}
if (st < 0)
break;
if (delta_alloc <= stream.total_out) {
delta_alloc = (delta_alloc +1024) * 3 / 2;
delta_data = xrealloc(delta_data, delta_alloc);
stream.next_out = delta_data + stream.total_out;
stream.avail_out = delta_alloc - stream.total_out;
}
}
inflateEnd(&stream);
if (st != Z_STREAM_END) {
free(delta_data);
return -1;
}
base = read_sha1_file(pack+1, type, &base_size);
if (!base)
die("failed to read delta-pack base object");
result = patch_delta(base, base_size,
delta_data, delta_size,
&result_size);
if (!result)
die("failed to apply delta");
free(delta_data);
if (write_sha1_file(result, result_size, type, sha1) < 0)
die("failed to write %s (%s)",
sha1_to_hex(entry->sha1), type);
free(result);
printf("%s %s\n", sha1_to_hex(sha1), type);
if (memcmp(sha1, entry->sha1, 20))
die("resulting %s have wrong SHA1", type);
return 0;
}
static void unpack_entry(struct pack_entry *entry) static void unpack_entry(struct pack_entry *entry)
{ {
unsigned long size;
unsigned long offset; unsigned long offset;
unsigned char *pack; unsigned char *pack;
@ -100,12 +260,10 @@ static void unpack_entry(struct pack_entry *entry)
offset = pack_size - offset; offset = pack_size - offset;
switch (*pack) { switch (*pack) {
case 'C': case 'T': case 'B': case 'C': case 'T': case 'B':
size = (pack[1] << 24) + (pack[2] << 16) + (pack[3] << 8) + pack[4]; unpack_non_delta_entry(entry, pack);
printf("%s %c %lu\n", sha1_to_hex(entry->sha1), *pack, size);
break; break;
case 'D': case 'D':
printf("%s D", sha1_to_hex(entry->sha1)); unpack_delta_entry(entry, pack);
printf(" %s\n", sha1_to_hex(pack+1));
break; break;
default: default:
die("corrupted pack file"); die("corrupted pack file");
@ -130,8 +288,6 @@ static void unpack_all(void)
int main(int argc, char **argv) int main(int argc, char **argv)
{ {
int i; int i;
unsigned long idx_size;
void *index;
for (i = 1 ; i < argc; i++) { for (i = 1 ; i < argc; i++) {
const char *arg = argv[i]; const char *arg = argv[i];
@ -149,9 +305,9 @@ int main(int argc, char **argv)
} }
if (!base_name) if (!base_name)
usage(unpack_usage); usage(unpack_usage);
index = map_file("idx", &idx_size); index_base = map_file("idx", &index_size);
pack_base = map_file("pack", &pack_size); pack_base = map_file("pack", &pack_size);
if (check_index(index, idx_size) < 0) if (check_index() < 0)
die("bad index file"); die("bad index file");
unpack_all(); unpack_all();
return 0; return 0;