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git/upload-pack.c
Nicolas Pitre 6523078b96 make shallow repository deepening more network efficient
First of all, I can't find any reason why thin pack generation is
explicitly disabled when dealing with a shallow repository.  The
possible delta base objects are collected from the edge commits which
are always obtained through history walking with the same shallow refs
as the client, Therefore the client is always going to have those base
objects available. So let's remove that restriction.

Then we can make shallow repository deepening much more efficient by
using the remote's unshallowed commits as edge commits to get preferred
base objects for thin pack generation.  On git.git, this makes the data
transfer for the deepening of a shallow repository from depth 1 to depth 2
around 134 KB instead of 3.68 MB.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-09-05 22:25:26 -07:00

660 lines
16 KiB
C

#include "cache.h"
#include "refs.h"
#include "pkt-line.h"
#include "sideband.h"
#include "tag.h"
#include "object.h"
#include "commit.h"
#include "exec_cmd.h"
#include "diff.h"
#include "revision.h"
#include "list-objects.h"
#include "run-command.h"
static const char upload_pack_usage[] = "git upload-pack [--strict] [--timeout=nn] <dir>";
/* bits #0..7 in revision.h, #8..10 in commit.c */
#define THEY_HAVE (1u << 11)
#define OUR_REF (1u << 12)
#define WANTED (1u << 13)
#define COMMON_KNOWN (1u << 14)
#define REACHABLE (1u << 15)
#define SHALLOW (1u << 16)
#define NOT_SHALLOW (1u << 17)
#define CLIENT_SHALLOW (1u << 18)
static unsigned long oldest_have;
static int multi_ack, nr_our_refs;
static int use_thin_pack, use_ofs_delta, use_include_tag;
static int no_progress;
static struct object_array have_obj;
static struct object_array want_obj;
static struct object_array extra_edge_obj;
static unsigned int timeout;
/* 0 for no sideband,
* otherwise maximum packet size (up to 65520 bytes).
*/
static int use_sideband;
static int debug_fd;
static void reset_timeout(void)
{
alarm(timeout);
}
static int strip(char *line, int len)
{
if (len && line[len-1] == '\n')
line[--len] = 0;
return len;
}
static ssize_t send_client_data(int fd, const char *data, ssize_t sz)
{
if (use_sideband)
return send_sideband(1, fd, data, sz, use_sideband);
if (fd == 3)
/* emergency quit */
fd = 2;
if (fd == 2) {
/* XXX: are we happy to lose stuff here? */
xwrite(fd, data, sz);
return sz;
}
return safe_write(fd, data, sz);
}
static FILE *pack_pipe = NULL;
static void show_commit(struct commit *commit, void *data)
{
if (commit->object.flags & BOUNDARY)
fputc('-', pack_pipe);
if (fputs(sha1_to_hex(commit->object.sha1), pack_pipe) < 0)
die("broken output pipe");
fputc('\n', pack_pipe);
fflush(pack_pipe);
free(commit->buffer);
commit->buffer = NULL;
}
static void show_object(struct object *obj, const struct name_path *path, const char *component)
{
/* An object with name "foo\n0000000..." can be used to
* confuse downstream git-pack-objects very badly.
*/
const char *name = path_name(path, component);
const char *ep = strchr(name, '\n');
if (ep) {
fprintf(pack_pipe, "%s %.*s\n", sha1_to_hex(obj->sha1),
(int) (ep - name),
name);
}
else
fprintf(pack_pipe, "%s %s\n",
sha1_to_hex(obj->sha1), name);
free((char *)name);
}
static void show_edge(struct commit *commit)
{
fprintf(pack_pipe, "-%s\n", sha1_to_hex(commit->object.sha1));
}
static int do_rev_list(int fd, void *create_full_pack)
{
int i;
struct rev_info revs;
pack_pipe = fdopen(fd, "w");
if (create_full_pack)
use_thin_pack = 0; /* no point doing it */
init_revisions(&revs, NULL);
revs.tag_objects = 1;
revs.tree_objects = 1;
revs.blob_objects = 1;
if (use_thin_pack)
revs.edge_hint = 1;
if (create_full_pack) {
const char *args[] = {"rev-list", "--all", NULL};
setup_revisions(2, args, &revs, NULL);
} else {
for (i = 0; i < want_obj.nr; i++) {
struct object *o = want_obj.objects[i].item;
/* why??? */
o->flags &= ~UNINTERESTING;
add_pending_object(&revs, o, NULL);
}
for (i = 0; i < have_obj.nr; i++) {
struct object *o = have_obj.objects[i].item;
o->flags |= UNINTERESTING;
add_pending_object(&revs, o, NULL);
}
setup_revisions(0, NULL, &revs, NULL);
}
if (prepare_revision_walk(&revs))
die("revision walk setup failed");
mark_edges_uninteresting(revs.commits, &revs, show_edge);
if (use_thin_pack)
for (i = 0; i < extra_edge_obj.nr; i++)
fprintf(pack_pipe, "-%s\n", sha1_to_hex(
extra_edge_obj.objects[i].item->sha1));
traverse_commit_list(&revs, show_commit, show_object, NULL);
fflush(pack_pipe);
fclose(pack_pipe);
return 0;
}
static void create_pack_file(void)
{
struct async rev_list;
struct child_process pack_objects;
int create_full_pack = (nr_our_refs == want_obj.nr && !have_obj.nr);
char data[8193], progress[128];
char abort_msg[] = "aborting due to possible repository "
"corruption on the remote side.";
int buffered = -1;
ssize_t sz;
const char *argv[10];
int arg = 0;
rev_list.proc = do_rev_list;
/* .data is just a boolean: any non-NULL value will do */
rev_list.data = create_full_pack ? &rev_list : NULL;
if (start_async(&rev_list))
die("git upload-pack: unable to fork git-rev-list");
argv[arg++] = "pack-objects";
argv[arg++] = "--stdout";
if (!no_progress)
argv[arg++] = "--progress";
if (use_ofs_delta)
argv[arg++] = "--delta-base-offset";
if (use_include_tag)
argv[arg++] = "--include-tag";
argv[arg++] = NULL;
memset(&pack_objects, 0, sizeof(pack_objects));
pack_objects.in = rev_list.out; /* start_command closes it */
pack_objects.out = -1;
pack_objects.err = -1;
pack_objects.git_cmd = 1;
pack_objects.argv = argv;
if (start_command(&pack_objects))
die("git upload-pack: unable to fork git-pack-objects");
/* We read from pack_objects.err to capture stderr output for
* progress bar, and pack_objects.out to capture the pack data.
*/
while (1) {
struct pollfd pfd[2];
int pe, pu, pollsize;
reset_timeout();
pollsize = 0;
pe = pu = -1;
if (0 <= pack_objects.out) {
pfd[pollsize].fd = pack_objects.out;
pfd[pollsize].events = POLLIN;
pu = pollsize;
pollsize++;
}
if (0 <= pack_objects.err) {
pfd[pollsize].fd = pack_objects.err;
pfd[pollsize].events = POLLIN;
pe = pollsize;
pollsize++;
}
if (!pollsize)
break;
if (poll(pfd, pollsize, -1) < 0) {
if (errno != EINTR) {
error("poll failed, resuming: %s",
strerror(errno));
sleep(1);
}
continue;
}
if (0 <= pu && (pfd[pu].revents & (POLLIN|POLLHUP))) {
/* Data ready; we keep the last byte to ourselves
* in case we detect broken rev-list, so that we
* can leave the stream corrupted. This is
* unfortunate -- unpack-objects would happily
* accept a valid packdata with trailing garbage,
* so appending garbage after we pass all the
* pack data is not good enough to signal
* breakage to downstream.
*/
char *cp = data;
ssize_t outsz = 0;
if (0 <= buffered) {
*cp++ = buffered;
outsz++;
}
sz = xread(pack_objects.out, cp,
sizeof(data) - outsz);
if (0 < sz)
;
else if (sz == 0) {
close(pack_objects.out);
pack_objects.out = -1;
}
else
goto fail;
sz += outsz;
if (1 < sz) {
buffered = data[sz-1] & 0xFF;
sz--;
}
else
buffered = -1;
sz = send_client_data(1, data, sz);
if (sz < 0)
goto fail;
}
if (0 <= pe && (pfd[pe].revents & (POLLIN|POLLHUP))) {
/* Status ready; we ship that in the side-band
* or dump to the standard error.
*/
sz = xread(pack_objects.err, progress,
sizeof(progress));
if (0 < sz)
send_client_data(2, progress, sz);
else if (sz == 0) {
close(pack_objects.err);
pack_objects.err = -1;
}
else
goto fail;
}
}
if (finish_command(&pack_objects)) {
error("git upload-pack: git-pack-objects died with error.");
goto fail;
}
if (finish_async(&rev_list))
goto fail; /* error was already reported */
/* flush the data */
if (0 <= buffered) {
data[0] = buffered;
sz = send_client_data(1, data, 1);
if (sz < 0)
goto fail;
fprintf(stderr, "flushed.\n");
}
if (use_sideband)
packet_flush(1);
return;
fail:
send_client_data(3, abort_msg, sizeof(abort_msg));
die("git upload-pack: %s", abort_msg);
}
static int got_sha1(char *hex, unsigned char *sha1)
{
struct object *o;
int we_knew_they_have = 0;
if (get_sha1_hex(hex, sha1))
die("git upload-pack: expected SHA1 object, got '%s'", hex);
if (!has_sha1_file(sha1))
return -1;
o = lookup_object(sha1);
if (!(o && o->parsed))
o = parse_object(sha1);
if (!o)
die("oops (%s)", sha1_to_hex(sha1));
if (o->type == OBJ_COMMIT) {
struct commit_list *parents;
struct commit *commit = (struct commit *)o;
if (o->flags & THEY_HAVE)
we_knew_they_have = 1;
else
o->flags |= THEY_HAVE;
if (!oldest_have || (commit->date < oldest_have))
oldest_have = commit->date;
for (parents = commit->parents;
parents;
parents = parents->next)
parents->item->object.flags |= THEY_HAVE;
}
if (!we_knew_they_have) {
add_object_array(o, NULL, &have_obj);
return 1;
}
return 0;
}
static int reachable(struct commit *want)
{
struct commit_list *work = NULL;
insert_by_date(want, &work);
while (work) {
struct commit_list *list = work->next;
struct commit *commit = work->item;
free(work);
work = list;
if (commit->object.flags & THEY_HAVE) {
want->object.flags |= COMMON_KNOWN;
break;
}
if (!commit->object.parsed)
parse_object(commit->object.sha1);
if (commit->object.flags & REACHABLE)
continue;
commit->object.flags |= REACHABLE;
if (commit->date < oldest_have)
continue;
for (list = commit->parents; list; list = list->next) {
struct commit *parent = list->item;
if (!(parent->object.flags & REACHABLE))
insert_by_date(parent, &work);
}
}
want->object.flags |= REACHABLE;
clear_commit_marks(want, REACHABLE);
free_commit_list(work);
return (want->object.flags & COMMON_KNOWN);
}
static int ok_to_give_up(void)
{
int i;
if (!have_obj.nr)
return 0;
for (i = 0; i < want_obj.nr; i++) {
struct object *want = want_obj.objects[i].item;
if (want->flags & COMMON_KNOWN)
continue;
want = deref_tag(want, "a want line", 0);
if (!want || want->type != OBJ_COMMIT) {
/* no way to tell if this is reachable by
* looking at the ancestry chain alone, so
* leave a note to ourselves not to worry about
* this object anymore.
*/
want_obj.objects[i].item->flags |= COMMON_KNOWN;
continue;
}
if (!reachable((struct commit *)want))
return 0;
}
return 1;
}
static int get_common_commits(void)
{
static char line[1000];
unsigned char sha1[20];
char hex[41], last_hex[41];
save_commit_buffer = 0;
for(;;) {
int len = packet_read_line(0, line, sizeof(line));
reset_timeout();
if (!len) {
if (have_obj.nr == 0 || multi_ack)
packet_write(1, "NAK\n");
continue;
}
strip(line, len);
if (!prefixcmp(line, "have ")) {
switch (got_sha1(line+5, sha1)) {
case -1: /* they have what we do not */
if (multi_ack && ok_to_give_up())
packet_write(1, "ACK %s continue\n",
sha1_to_hex(sha1));
break;
default:
memcpy(hex, sha1_to_hex(sha1), 41);
if (multi_ack) {
const char *msg = "ACK %s continue\n";
packet_write(1, msg, hex);
memcpy(last_hex, hex, 41);
}
else if (have_obj.nr == 1)
packet_write(1, "ACK %s\n", hex);
break;
}
continue;
}
if (!strcmp(line, "done")) {
if (have_obj.nr > 0) {
if (multi_ack)
packet_write(1, "ACK %s\n", last_hex);
return 0;
}
packet_write(1, "NAK\n");
return -1;
}
die("git upload-pack: expected SHA1 list, got '%s'", line);
}
}
static void receive_needs(void)
{
struct object_array shallows = {0, 0, NULL};
static char line[1000];
int len, depth = 0;
if (debug_fd)
write_in_full(debug_fd, "#S\n", 3);
for (;;) {
struct object *o;
unsigned char sha1_buf[20];
len = packet_read_line(0, line, sizeof(line));
reset_timeout();
if (!len)
break;
if (debug_fd)
write_in_full(debug_fd, line, len);
if (!prefixcmp(line, "shallow ")) {
unsigned char sha1[20];
struct object *object;
if (get_sha1(line + 8, sha1))
die("invalid shallow line: %s", line);
object = parse_object(sha1);
if (!object)
die("did not find object for %s", line);
object->flags |= CLIENT_SHALLOW;
add_object_array(object, NULL, &shallows);
continue;
}
if (!prefixcmp(line, "deepen ")) {
char *end;
depth = strtol(line + 7, &end, 0);
if (end == line + 7 || depth <= 0)
die("Invalid deepen: %s", line);
continue;
}
if (prefixcmp(line, "want ") ||
get_sha1_hex(line+5, sha1_buf))
die("git upload-pack: protocol error, "
"expected to get sha, not '%s'", line);
if (strstr(line+45, "multi_ack"))
multi_ack = 1;
if (strstr(line+45, "thin-pack"))
use_thin_pack = 1;
if (strstr(line+45, "ofs-delta"))
use_ofs_delta = 1;
if (strstr(line+45, "side-band-64k"))
use_sideband = LARGE_PACKET_MAX;
else if (strstr(line+45, "side-band"))
use_sideband = DEFAULT_PACKET_MAX;
if (strstr(line+45, "no-progress"))
no_progress = 1;
if (strstr(line+45, "include-tag"))
use_include_tag = 1;
/* We have sent all our refs already, and the other end
* should have chosen out of them; otherwise they are
* asking for nonsense.
*
* Hmph. We may later want to allow "want" line that
* asks for something like "master~10" (symbolic)...
* would it make sense? I don't know.
*/
o = lookup_object(sha1_buf);
if (!o || !(o->flags & OUR_REF))
die("git upload-pack: not our ref %s", line+5);
if (!(o->flags & WANTED)) {
o->flags |= WANTED;
add_object_array(o, NULL, &want_obj);
}
}
if (debug_fd)
write_in_full(debug_fd, "#E\n", 3);
if (depth == 0 && shallows.nr == 0)
return;
if (depth > 0) {
struct commit_list *result, *backup;
int i;
backup = result = get_shallow_commits(&want_obj, depth,
SHALLOW, NOT_SHALLOW);
while (result) {
struct object *object = &result->item->object;
if (!(object->flags & (CLIENT_SHALLOW|NOT_SHALLOW))) {
packet_write(1, "shallow %s",
sha1_to_hex(object->sha1));
register_shallow(object->sha1);
}
result = result->next;
}
free_commit_list(backup);
for (i = 0; i < shallows.nr; i++) {
struct object *object = shallows.objects[i].item;
if (object->flags & NOT_SHALLOW) {
struct commit_list *parents;
packet_write(1, "unshallow %s",
sha1_to_hex(object->sha1));
object->flags &= ~CLIENT_SHALLOW;
/* make sure the real parents are parsed */
unregister_shallow(object->sha1);
object->parsed = 0;
if (parse_commit((struct commit *)object))
die("invalid commit");
parents = ((struct commit *)object)->parents;
while (parents) {
add_object_array(&parents->item->object,
NULL, &want_obj);
parents = parents->next;
}
add_object_array(object, NULL, &extra_edge_obj);
}
/* make sure commit traversal conforms to client */
register_shallow(object->sha1);
}
packet_flush(1);
} else
if (shallows.nr > 0) {
int i;
for (i = 0; i < shallows.nr; i++)
register_shallow(shallows.objects[i].item->sha1);
}
free(shallows.objects);
}
static int send_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
{
static const char *capabilities = "multi_ack thin-pack side-band"
" side-band-64k ofs-delta shallow no-progress"
" include-tag";
struct object *o = parse_object(sha1);
if (!o)
die("git upload-pack: cannot find object %s:", sha1_to_hex(sha1));
if (capabilities)
packet_write(1, "%s %s%c%s\n", sha1_to_hex(sha1), refname,
0, capabilities);
else
packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname);
capabilities = NULL;
if (!(o->flags & OUR_REF)) {
o->flags |= OUR_REF;
nr_our_refs++;
}
if (o->type == OBJ_TAG) {
o = deref_tag(o, refname, 0);
if (o)
packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname);
}
return 0;
}
static void upload_pack(void)
{
reset_timeout();
head_ref(send_ref, NULL);
for_each_ref(send_ref, NULL);
packet_flush(1);
receive_needs();
if (want_obj.nr) {
get_common_commits();
create_pack_file();
}
}
int main(int argc, char **argv)
{
char *dir;
int i;
int strict = 0;
git_extract_argv0_path(argv[0]);
for (i = 1; i < argc; i++) {
char *arg = argv[i];
if (arg[0] != '-')
break;
if (!strcmp(arg, "--strict")) {
strict = 1;
continue;
}
if (!prefixcmp(arg, "--timeout=")) {
timeout = atoi(arg+10);
continue;
}
if (!strcmp(arg, "--")) {
i++;
break;
}
}
if (i != argc-1)
usage(upload_pack_usage);
setup_path();
dir = argv[i];
if (!enter_repo(dir, strict))
die("'%s' does not appear to be a git repository", dir);
if (is_repository_shallow())
die("attempt to fetch/clone from a shallow repository");
if (getenv("GIT_DEBUG_SEND_PACK"))
debug_fd = atoi(getenv("GIT_DEBUG_SEND_PACK"));
upload_pack();
return 0;
}