make index-pack able to complete thin packs.

A new flag, --fix-thin, instructs git-index-pack to append any missing
objects to a thin pack to make it self contained and indexable. Of course
objects missing from the pack must be present elsewhere in the local
repository.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
This commit is contained in:
Nicolas Pitre
2006-10-25 23:28:17 -04:00
committed by Junio C Hamano
parent e42797f5b6
commit 636171cb80
2 changed files with 225 additions and 45 deletions

View File

@ -8,7 +8,7 @@
#include "tree.h"
static const char index_pack_usage[] =
"git-index-pack [-o <index-file>] { <pack-file> | --stdin [<pack-file>] }";
"git-index-pack [-o <index-file>] { <pack-file> | --stdin [--fix-thin] [<pack-file>] }";
struct object_entry
{
@ -33,14 +33,15 @@ union delta_base {
struct delta_entry
{
struct object_entry *obj;
union delta_base base;
int obj_no;
};
static struct object_entry *objects;
static struct delta_entry *deltas;
static int nr_objects;
static int nr_deltas;
static int nr_resolved_deltas;
static int from_stdin;
@ -50,6 +51,18 @@ static unsigned long input_offset, input_len, consumed_bytes;
static SHA_CTX input_ctx;
static int input_fd, output_fd, mmap_fd;
/* Discard current buffer used content. */
static void flush()
{
if (input_offset) {
if (output_fd >= 0)
write_or_die(output_fd, input_buffer, input_offset);
SHA1_Update(&input_ctx, input_buffer, input_offset);
memcpy(input_buffer, input_buffer + input_offset, input_len);
input_offset = 0;
}
}
/*
* Make sure at least "min" bytes are available in the buffer, and
* return the pointer to the buffer.
@ -60,13 +73,7 @@ static void * fill(int min)
return input_buffer + input_offset;
if (min > sizeof(input_buffer))
die("cannot fill %d bytes", min);
if (input_offset) {
if (output_fd >= 0)
write_or_die(output_fd, input_buffer, input_offset);
SHA1_Update(&input_ctx, input_buffer, input_offset);
memcpy(input_buffer, input_buffer + input_offset, input_len);
input_offset = 0;
}
flush();
do {
int ret = xread(input_fd, input_buffer + input_len,
sizeof(input_buffer) - input_len);
@ -323,10 +330,9 @@ static void sha1_object(const void *data, unsigned long size,
SHA1_Final(sha1, &ctx);
}
static void resolve_delta(struct delta_entry *delta, void *base_data,
static void resolve_delta(struct object_entry *delta_obj, void *base_data,
unsigned long base_size, enum object_type type)
{
struct object_entry *obj = delta->obj;
void *delta_data;
unsigned long delta_size;
void *result;
@ -334,29 +340,34 @@ static void resolve_delta(struct delta_entry *delta, void *base_data,
union delta_base delta_base;
int j, first, last;
obj->real_type = type;
delta_data = get_data_from_pack(obj);
delta_size = obj->size;
delta_obj->real_type = type;
delta_data = get_data_from_pack(delta_obj);
delta_size = delta_obj->size;
result = patch_delta(base_data, base_size, delta_data, delta_size,
&result_size);
free(delta_data);
if (!result)
bad_object(obj->offset, "failed to apply delta");
sha1_object(result, result_size, type, obj->sha1);
bad_object(delta_obj->offset, "failed to apply delta");
sha1_object(result, result_size, type, delta_obj->sha1);
nr_resolved_deltas++;
hashcpy(delta_base.sha1, obj->sha1);
hashcpy(delta_base.sha1, delta_obj->sha1);
if (!find_delta_childs(&delta_base, &first, &last)) {
for (j = first; j <= last; j++)
if (deltas[j].obj->type == OBJ_REF_DELTA)
resolve_delta(&deltas[j], result, result_size, type);
for (j = first; j <= last; j++) {
struct object_entry *child = objects + deltas[j].obj_no;
if (child->real_type == OBJ_REF_DELTA)
resolve_delta(child, result, result_size, type);
}
}
memset(&delta_base, 0, sizeof(delta_base));
delta_base.offset = obj->offset;
delta_base.offset = delta_obj->offset;
if (!find_delta_childs(&delta_base, &first, &last)) {
for (j = first; j <= last; j++)
if (deltas[j].obj->type == OBJ_OFS_DELTA)
resolve_delta(&deltas[j], result, result_size, type);
for (j = first; j <= last; j++) {
struct object_entry *child = objects + deltas[j].obj_no;
if (child->real_type == OBJ_OFS_DELTA)
resolve_delta(child, result, result_size, type);
}
}
free(result);
@ -389,7 +400,7 @@ static void parse_pack_objects(unsigned char *sha1)
obj->real_type = obj->type;
if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA) {
nr_deltas++;
delta->obj = obj;
delta->obj_no = i;
delta++;
} else
sha1_object(data, obj->size, obj->type, obj->sha1);
@ -398,18 +409,15 @@ static void parse_pack_objects(unsigned char *sha1)
objects[i].offset = consumed_bytes;
/* Check pack integrity */
SHA1_Update(&input_ctx, input_buffer, input_offset);
flush();
SHA1_Final(sha1, &input_ctx);
if (hashcmp(fill(20), sha1))
die("pack is corrupted (SHA1 mismatch)");
use(20);
if (output_fd >= 0)
write_or_die(output_fd, input_buffer, input_offset);
/* If input_fd is a file, we should have reached its end now. */
if (fstat(input_fd, &st))
die("cannot fstat packfile: %s", strerror(errno));
if (S_ISREG(st.st_mode) && st.st_size != consumed_bytes)
if (S_ISREG(st.st_mode) && st.st_size != consumed_bytes + 20)
die("pack has junk at the end");
/* Sort deltas by base SHA1/offset for fast searching */
@ -440,24 +448,161 @@ static void parse_pack_objects(unsigned char *sha1)
continue;
data = get_data_from_pack(obj);
if (ref)
for (j = ref_first; j <= ref_last; j++)
if (deltas[j].obj->type == OBJ_REF_DELTA)
resolve_delta(&deltas[j], data,
for (j = ref_first; j <= ref_last; j++) {
struct object_entry *child = objects + deltas[j].obj_no;
if (child->real_type == OBJ_REF_DELTA)
resolve_delta(child, data,
obj->size, obj->type);
}
if (ofs)
for (j = ofs_first; j <= ofs_last; j++)
if (deltas[j].obj->type == OBJ_OFS_DELTA)
resolve_delta(&deltas[j], data,
for (j = ofs_first; j <= ofs_last; j++) {
struct object_entry *child = objects + deltas[j].obj_no;
if (child->real_type == OBJ_OFS_DELTA)
resolve_delta(child, data,
obj->size, obj->type);
}
free(data);
}
}
/* Check for unresolved deltas */
for (i = 0; i < nr_deltas; i++) {
if (deltas[i].obj->real_type == OBJ_REF_DELTA ||
deltas[i].obj->real_type == OBJ_OFS_DELTA)
die("pack has unresolved deltas");
static int write_compressed(int fd, void *in, unsigned int size)
{
z_stream stream;
unsigned long maxsize;
void *out;
memset(&stream, 0, sizeof(stream));
deflateInit(&stream, zlib_compression_level);
maxsize = deflateBound(&stream, size);
out = xmalloc(maxsize);
/* Compress it */
stream.next_in = in;
stream.avail_in = size;
stream.next_out = out;
stream.avail_out = maxsize;
while (deflate(&stream, Z_FINISH) == Z_OK);
deflateEnd(&stream);
size = stream.total_out;
write_or_die(fd, out, size);
free(out);
return size;
}
static void append_obj_to_pack(void *buf,
unsigned long size, enum object_type type)
{
struct object_entry *obj = &objects[nr_objects++];
unsigned char header[10];
unsigned long s = size;
int n = 0;
unsigned char c = (type << 4) | (s & 15);
s >>= 4;
while (s) {
header[n++] = c | 0x80;
c = s & 0x7f;
s >>= 7;
}
header[n++] = c;
write_or_die(output_fd, header, n);
obj[1].offset = obj[0].offset + n;
obj[1].offset += write_compressed(output_fd, buf, size);
sha1_object(buf, size, type, obj->sha1);
}
static int delta_pos_compare(const void *_a, const void *_b)
{
struct delta_entry *a = *(struct delta_entry **)_a;
struct delta_entry *b = *(struct delta_entry **)_b;
return a->obj_no - b->obj_no;
}
static void fix_unresolved_deltas(int nr_unresolved)
{
struct delta_entry **sorted_by_pos;
int i, n = 0;
/*
* Since many unresolved deltas may well be themselves base objects
* for more unresolved deltas, we really want to include the
* smallest number of base objects that would cover as much delta
* as possible by picking the
* trunc deltas first, allowing for other deltas to resolve without
* additional base objects. Since most base objects are to be found
* before deltas depending on them, a good heuristic is to start
* resolving deltas in the same order as their position in the pack.
*/
sorted_by_pos = xmalloc(nr_unresolved * sizeof(*sorted_by_pos));
for (i = 0; i < nr_deltas; i++) {
if (objects[deltas[i].obj_no].real_type != OBJ_REF_DELTA)
continue;
sorted_by_pos[n++] = &deltas[i];
}
qsort(sorted_by_pos, n, sizeof(*sorted_by_pos), delta_pos_compare);
for (i = 0; i < n; i++) {
struct delta_entry *d = sorted_by_pos[i];
void *data;
unsigned long size;
char type[10];
enum object_type obj_type;
int j, first, last;
if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
continue;
data = read_sha1_file(d->base.sha1, type, &size);
if (!data)
continue;
if (!strcmp(type, blob_type)) obj_type = OBJ_BLOB;
else if (!strcmp(type, tree_type)) obj_type = OBJ_TREE;
else if (!strcmp(type, commit_type)) obj_type = OBJ_COMMIT;
else if (!strcmp(type, tag_type)) obj_type = OBJ_TAG;
else die("base object %s is of type '%s'",
sha1_to_hex(d->base.sha1), type);
find_delta_childs(&d->base, &first, &last);
for (j = first; j <= last; j++) {
struct object_entry *child = objects + deltas[j].obj_no;
if (child->real_type == OBJ_REF_DELTA)
resolve_delta(child, data, size, obj_type);
}
append_obj_to_pack(data, size, obj_type);
free(data);
}
free(sorted_by_pos);
}
static void readjust_pack_header_and_sha1(unsigned char *sha1)
{
struct pack_header hdr;
SHA_CTX ctx;
int size;
/* Rewrite pack header with updated object number */
if (lseek(output_fd, 0, SEEK_SET) != 0)
die("cannot seek back: %s", strerror(errno));
if (xread(output_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
die("cannot read pack header back: %s", strerror(errno));
hdr.hdr_entries = htonl(nr_objects);
if (lseek(output_fd, 0, SEEK_SET) != 0)
die("cannot seek back: %s", strerror(errno));
write_or_die(output_fd, &hdr, sizeof(hdr));
if (lseek(output_fd, 0, SEEK_SET) != 0)
die("cannot seek back: %s", strerror(errno));
/* Recompute and store the new pack's SHA1 */
SHA1_Init(&ctx);
do {
unsigned char *buf[4096];
size = xread(output_fd, buf, sizeof(buf));
if (size < 0)
die("cannot read pack data back: %s", strerror(errno));
SHA1_Update(&ctx, buf, size);
} while (size > 0);
SHA1_Final(sha1, &ctx);
write_or_die(output_fd, sha1, 20);
}
static int sha1_compare(const void *_a, const void *_b)
@ -588,7 +733,7 @@ static void final(const char *final_pack_name, const char *curr_pack_name,
int main(int argc, char **argv)
{
int i;
int i, fix_thin_pack = 0;
const char *curr_pack, *pack_name = NULL;
const char *curr_index, *index_name = NULL;
char *index_name_buf = NULL;
@ -600,6 +745,8 @@ int main(int argc, char **argv)
if (*arg == '-') {
if (!strcmp(arg, "--stdin")) {
from_stdin = 1;
} else if (!strcmp(arg, "--fix-thin")) {
fix_thin_pack = 1;
} else if (!strcmp(arg, "-o")) {
if (index_name || (i+1) >= argc)
usage(index_pack_usage);
@ -616,6 +763,8 @@ int main(int argc, char **argv)
if (!pack_name && !from_stdin)
usage(index_pack_usage);
if (fix_thin_pack && !from_stdin)
die("--fix-thin cannot be used without --stdin");
if (!index_name && pack_name) {
int len = strlen(pack_name);
if (!has_extension(pack_name, ".pack"))
@ -629,9 +778,28 @@ int main(int argc, char **argv)
curr_pack = open_pack_file(pack_name);
parse_pack_header();
objects = xcalloc(nr_objects + 1, sizeof(struct object_entry));
deltas = xcalloc(nr_objects, sizeof(struct delta_entry));
objects = xmalloc((nr_objects + 1) * sizeof(struct object_entry));
deltas = xmalloc(nr_objects * sizeof(struct delta_entry));
parse_pack_objects(sha1);
if (nr_deltas != nr_resolved_deltas) {
if (fix_thin_pack) {
int nr_unresolved = nr_deltas - nr_resolved_deltas;
if (nr_unresolved <= 0)
die("confusion beyond insanity");
objects = xrealloc(objects,
(nr_objects + nr_unresolved + 1)
* sizeof(*objects));
fix_unresolved_deltas(nr_unresolved);
readjust_pack_header_and_sha1(sha1);
}
if (nr_deltas != nr_resolved_deltas)
die("pack has %d unresolved deltas",
nr_deltas - nr_resolved_deltas);
} else {
/* Flush remaining pack final 20-byte SHA1. */
use(20);
flush();
}
free(deltas);
curr_index = write_index_file(index_name, sha1);
final(pack_name, curr_pack, index_name, curr_index, sha1);