1
0
Fork 0
mirror of https://github.com/git/git.git synced 2024-05-25 04:16:09 +02:00
git/builtin-fetch-pack.c
Johannes Sixt 1f759eeede fetch-pack: Prepare for a side-band demultiplexer in a thread.
get_pack() receives a pair of file descriptors that communicate with
upload-pack at the remote end. In order to support the case where the
side-band demultiplexer runs in a thread, and, hence, in the same process
as the main routine, we must not close the readable file descriptor early.

The handling of the readable fd is changed in the case where upload-pack
supports side-band communication: The old code closed the fd after it was
inherited to the side-band demultiplexer process. Now we do not close it.
The caller (do_fetch_pack) will close it later anyway. The demultiplexer
is the only reader, it does not matter that the fd remains open in the
main process as well as in unpack-objects/index-pack, which inherits it.

The writable fd is not needed in get_pack(), hence, the old code closed
the fd. For symmetry with the readable fd, we now do not close it; the
caller (do_fetch_pack) will close it later anyway. Therefore, the new
behavior is that the channel now remains open during the entire
conversation, but this has no ill effects because upload-pack does not read
from it once it has begun to send the pack data. For the same reason it
does not matter that the writable fd is now inherited to the demultiplexer
and unpack-objects/index-pack processes.

Signed-off-by: Johannes Sixt <johannes.sixt@telecom.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-11-17 20:27:29 -08:00

796 lines
18 KiB
C

#include "cache.h"
#include "refs.h"
#include "pkt-line.h"
#include "commit.h"
#include "tag.h"
#include "exec_cmd.h"
#include "pack.h"
#include "sideband.h"
#include "fetch-pack.h"
#include "run-command.h"
static int transfer_unpack_limit = -1;
static int fetch_unpack_limit = -1;
static int unpack_limit = 100;
static struct fetch_pack_args args = {
/* .uploadpack = */ "git-upload-pack",
};
static const char fetch_pack_usage[] =
"git-fetch-pack [--all] [--quiet|-q] [--keep|-k] [--thin] [--upload-pack=<git-upload-pack>] [--depth=<n>] [--no-progress] [-v] [<host>:]<directory> [<refs>...]";
#define COMPLETE (1U << 0)
#define COMMON (1U << 1)
#define COMMON_REF (1U << 2)
#define SEEN (1U << 3)
#define POPPED (1U << 4)
/*
* After sending this many "have"s if we do not get any new ACK , we
* give up traversing our history.
*/
#define MAX_IN_VAIN 256
static struct commit_list *rev_list;
static int non_common_revs, multi_ack, use_sideband;
static void rev_list_push(struct commit *commit, int mark)
{
if (!(commit->object.flags & mark)) {
commit->object.flags |= mark;
if (!(commit->object.parsed))
parse_commit(commit);
insert_by_date(commit, &rev_list);
if (!(commit->object.flags & COMMON))
non_common_revs++;
}
}
static int rev_list_insert_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
{
struct object *o = deref_tag(parse_object(sha1), path, 0);
if (o && o->type == OBJ_COMMIT)
rev_list_push((struct commit *)o, SEEN);
return 0;
}
/*
This function marks a rev and its ancestors as common.
In some cases, it is desirable to mark only the ancestors (for example
when only the server does not yet know that they are common).
*/
static void mark_common(struct commit *commit,
int ancestors_only, int dont_parse)
{
if (commit != NULL && !(commit->object.flags & COMMON)) {
struct object *o = (struct object *)commit;
if (!ancestors_only)
o->flags |= COMMON;
if (!(o->flags & SEEN))
rev_list_push(commit, SEEN);
else {
struct commit_list *parents;
if (!ancestors_only && !(o->flags & POPPED))
non_common_revs--;
if (!o->parsed && !dont_parse)
parse_commit(commit);
for (parents = commit->parents;
parents;
parents = parents->next)
mark_common(parents->item, 0, dont_parse);
}
}
}
/*
Get the next rev to send, ignoring the common.
*/
static const unsigned char* get_rev(void)
{
struct commit *commit = NULL;
while (commit == NULL) {
unsigned int mark;
struct commit_list* parents;
if (rev_list == NULL || non_common_revs == 0)
return NULL;
commit = rev_list->item;
if (!(commit->object.parsed))
parse_commit(commit);
commit->object.flags |= POPPED;
if (!(commit->object.flags & COMMON))
non_common_revs--;
parents = commit->parents;
if (commit->object.flags & COMMON) {
/* do not send "have", and ignore ancestors */
commit = NULL;
mark = COMMON | SEEN;
} else if (commit->object.flags & COMMON_REF)
/* send "have", and ignore ancestors */
mark = COMMON | SEEN;
else
/* send "have", also for its ancestors */
mark = SEEN;
while (parents) {
if (!(parents->item->object.flags & SEEN))
rev_list_push(parents->item, mark);
if (mark & COMMON)
mark_common(parents->item, 1, 0);
parents = parents->next;
}
rev_list = rev_list->next;
}
return commit->object.sha1;
}
static int find_common(int fd[2], unsigned char *result_sha1,
struct ref *refs)
{
int fetching;
int count = 0, flushes = 0, retval;
const unsigned char *sha1;
unsigned in_vain = 0;
int got_continue = 0;
for_each_ref(rev_list_insert_ref, NULL);
fetching = 0;
for ( ; refs ; refs = refs->next) {
unsigned char *remote = refs->old_sha1;
struct object *o;
/*
* If that object is complete (i.e. it is an ancestor of a
* local ref), we tell them we have it but do not have to
* tell them about its ancestors, which they already know
* about.
*
* We use lookup_object here because we are only
* interested in the case we *know* the object is
* reachable and we have already scanned it.
*/
if (((o = lookup_object(remote)) != NULL) &&
(o->flags & COMPLETE)) {
continue;
}
if (!fetching)
packet_write(fd[1], "want %s%s%s%s%s%s%s\n",
sha1_to_hex(remote),
(multi_ack ? " multi_ack" : ""),
(use_sideband == 2 ? " side-band-64k" : ""),
(use_sideband == 1 ? " side-band" : ""),
(args.use_thin_pack ? " thin-pack" : ""),
(args.no_progress ? " no-progress" : ""),
" ofs-delta");
else
packet_write(fd[1], "want %s\n", sha1_to_hex(remote));
fetching++;
}
if (is_repository_shallow())
write_shallow_commits(fd[1], 1);
if (args.depth > 0)
packet_write(fd[1], "deepen %d", args.depth);
packet_flush(fd[1]);
if (!fetching)
return 1;
if (args.depth > 0) {
char line[1024];
unsigned char sha1[20];
int len;
while ((len = packet_read_line(fd[0], line, sizeof(line)))) {
if (!prefixcmp(line, "shallow ")) {
if (get_sha1_hex(line + 8, sha1))
die("invalid shallow line: %s", line);
register_shallow(sha1);
continue;
}
if (!prefixcmp(line, "unshallow ")) {
if (get_sha1_hex(line + 10, sha1))
die("invalid unshallow line: %s", line);
if (!lookup_object(sha1))
die("object not found: %s", line);
/* make sure that it is parsed as shallow */
parse_object(sha1);
if (unregister_shallow(sha1))
die("no shallow found: %s", line);
continue;
}
die("expected shallow/unshallow, got %s", line);
}
}
flushes = 0;
retval = -1;
while ((sha1 = get_rev())) {
packet_write(fd[1], "have %s\n", sha1_to_hex(sha1));
if (args.verbose)
fprintf(stderr, "have %s\n", sha1_to_hex(sha1));
in_vain++;
if (!(31 & ++count)) {
int ack;
packet_flush(fd[1]);
flushes++;
/*
* We keep one window "ahead" of the other side, and
* will wait for an ACK only on the next one
*/
if (count == 32)
continue;
do {
ack = get_ack(fd[0], result_sha1);
if (args.verbose && ack)
fprintf(stderr, "got ack %d %s\n", ack,
sha1_to_hex(result_sha1));
if (ack == 1) {
flushes = 0;
multi_ack = 0;
retval = 0;
goto done;
} else if (ack == 2) {
struct commit *commit =
lookup_commit(result_sha1);
mark_common(commit, 0, 1);
retval = 0;
in_vain = 0;
got_continue = 1;
}
} while (ack);
flushes--;
if (got_continue && MAX_IN_VAIN < in_vain) {
if (args.verbose)
fprintf(stderr, "giving up\n");
break; /* give up */
}
}
}
done:
packet_write(fd[1], "done\n");
if (args.verbose)
fprintf(stderr, "done\n");
if (retval != 0) {
multi_ack = 0;
flushes++;
}
while (flushes || multi_ack) {
int ack = get_ack(fd[0], result_sha1);
if (ack) {
if (args.verbose)
fprintf(stderr, "got ack (%d) %s\n", ack,
sha1_to_hex(result_sha1));
if (ack == 1)
return 0;
multi_ack = 1;
continue;
}
flushes--;
}
return retval;
}
static struct commit_list *complete;
static int mark_complete(const char *path, const unsigned char *sha1, int flag, void *cb_data)
{
struct object *o = parse_object(sha1);
while (o && o->type == OBJ_TAG) {
struct tag *t = (struct tag *) o;
if (!t->tagged)
break; /* broken repository */
o->flags |= COMPLETE;
o = parse_object(t->tagged->sha1);
}
if (o && o->type == OBJ_COMMIT) {
struct commit *commit = (struct commit *)o;
commit->object.flags |= COMPLETE;
insert_by_date(commit, &complete);
}
return 0;
}
static void mark_recent_complete_commits(unsigned long cutoff)
{
while (complete && cutoff <= complete->item->date) {
if (args.verbose)
fprintf(stderr, "Marking %s as complete\n",
sha1_to_hex(complete->item->object.sha1));
pop_most_recent_commit(&complete, COMPLETE);
}
}
static void filter_refs(struct ref **refs, int nr_match, char **match)
{
struct ref **return_refs;
struct ref *newlist = NULL;
struct ref **newtail = &newlist;
struct ref *ref, *next;
struct ref *fastarray[32];
if (nr_match && !args.fetch_all) {
if (ARRAY_SIZE(fastarray) < nr_match)
return_refs = xcalloc(nr_match, sizeof(struct ref *));
else {
return_refs = fastarray;
memset(return_refs, 0, sizeof(struct ref *) * nr_match);
}
}
else
return_refs = NULL;
for (ref = *refs; ref; ref = next) {
next = ref->next;
if (!memcmp(ref->name, "refs/", 5) &&
check_ref_format(ref->name + 5))
; /* trash */
else if (args.fetch_all &&
(!args.depth || prefixcmp(ref->name, "refs/tags/") )) {
*newtail = ref;
ref->next = NULL;
newtail = &ref->next;
continue;
}
else {
int order = path_match(ref->name, nr_match, match);
if (order) {
return_refs[order-1] = ref;
continue; /* we will link it later */
}
}
free(ref);
}
if (!args.fetch_all) {
int i;
for (i = 0; i < nr_match; i++) {
ref = return_refs[i];
if (ref) {
*newtail = ref;
ref->next = NULL;
newtail = &ref->next;
}
}
if (return_refs != fastarray)
free(return_refs);
}
*refs = newlist;
}
static int everything_local(struct ref **refs, int nr_match, char **match)
{
struct ref *ref;
int retval;
unsigned long cutoff = 0;
track_object_refs = 0;
save_commit_buffer = 0;
for (ref = *refs; ref; ref = ref->next) {
struct object *o;
o = parse_object(ref->old_sha1);
if (!o)
continue;
/* We already have it -- which may mean that we were
* in sync with the other side at some time after
* that (it is OK if we guess wrong here).
*/
if (o->type == OBJ_COMMIT) {
struct commit *commit = (struct commit *)o;
if (!cutoff || cutoff < commit->date)
cutoff = commit->date;
}
}
if (!args.depth) {
for_each_ref(mark_complete, NULL);
if (cutoff)
mark_recent_complete_commits(cutoff);
}
/*
* Mark all complete remote refs as common refs.
* Don't mark them common yet; the server has to be told so first.
*/
for (ref = *refs; ref; ref = ref->next) {
struct object *o = deref_tag(lookup_object(ref->old_sha1),
NULL, 0);
if (!o || o->type != OBJ_COMMIT || !(o->flags & COMPLETE))
continue;
if (!(o->flags & SEEN)) {
rev_list_push((struct commit *)o, COMMON_REF | SEEN);
mark_common((struct commit *)o, 1, 1);
}
}
filter_refs(refs, nr_match, match);
for (retval = 1, ref = *refs; ref ; ref = ref->next) {
const unsigned char *remote = ref->old_sha1;
unsigned char local[20];
struct object *o;
o = lookup_object(remote);
if (!o || !(o->flags & COMPLETE)) {
retval = 0;
if (!args.verbose)
continue;
fprintf(stderr,
"want %s (%s)\n", sha1_to_hex(remote),
ref->name);
continue;
}
hashcpy(ref->new_sha1, local);
if (!args.verbose)
continue;
fprintf(stderr,
"already have %s (%s)\n", sha1_to_hex(remote),
ref->name);
}
return retval;
}
static int sideband_demux(int fd, void *data)
{
int *xd = data;
return recv_sideband("fetch-pack", xd[0], fd, 2);
}
static int get_pack(int xd[2], char **pack_lockfile)
{
struct async demux;
const char *argv[20];
char keep_arg[256];
char hdr_arg[256];
const char **av;
int do_keep = args.keep_pack;
struct child_process cmd;
memset(&demux, 0, sizeof(demux));
if (use_sideband) {
/* xd[] is talking with upload-pack; subprocess reads from
* xd[0], spits out band#2 to stderr, and feeds us band#1
* through demux->out.
*/
demux.proc = sideband_demux;
demux.data = xd;
if (start_async(&demux))
die("fetch-pack: unable to fork off sideband"
" demultiplexer");
}
else
demux.out = xd[0];
memset(&cmd, 0, sizeof(cmd));
cmd.argv = argv;
av = argv;
*hdr_arg = 0;
if (!args.keep_pack && unpack_limit) {
struct pack_header header;
if (read_pack_header(demux.out, &header))
die("protocol error: bad pack header");
snprintf(hdr_arg, sizeof(hdr_arg), "--pack_header=%u,%u",
ntohl(header.hdr_version), ntohl(header.hdr_entries));
if (ntohl(header.hdr_entries) < unpack_limit)
do_keep = 0;
else
do_keep = 1;
}
if (do_keep) {
if (pack_lockfile)
cmd.out = -1;
*av++ = "index-pack";
*av++ = "--stdin";
if (!args.quiet && !args.no_progress)
*av++ = "-v";
if (args.use_thin_pack)
*av++ = "--fix-thin";
if (args.lock_pack || unpack_limit) {
int s = sprintf(keep_arg,
"--keep=fetch-pack %d on ", getpid());
if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
strcpy(keep_arg + s, "localhost");
*av++ = keep_arg;
}
}
else {
*av++ = "unpack-objects";
if (args.quiet)
*av++ = "-q";
}
if (*hdr_arg)
*av++ = hdr_arg;
*av++ = NULL;
cmd.in = demux.out;
cmd.git_cmd = 1;
if (start_command(&cmd))
die("fetch-pack: unable to fork off %s", argv[0]);
if (do_keep && pack_lockfile)
*pack_lockfile = index_pack_lockfile(cmd.out);
if (finish_command(&cmd))
die("%s failed", argv[0]);
if (use_sideband && finish_async(&demux))
die("error in sideband demultiplexer");
return 0;
}
static struct ref *do_fetch_pack(int fd[2],
int nr_match,
char **match,
char **pack_lockfile)
{
struct ref *ref;
unsigned char sha1[20];
get_remote_heads(fd[0], &ref, 0, NULL, 0);
if (is_repository_shallow() && !server_supports("shallow"))
die("Server does not support shallow clients");
if (server_supports("multi_ack")) {
if (args.verbose)
fprintf(stderr, "Server supports multi_ack\n");
multi_ack = 1;
}
if (server_supports("side-band-64k")) {
if (args.verbose)
fprintf(stderr, "Server supports side-band-64k\n");
use_sideband = 2;
}
else if (server_supports("side-band")) {
if (args.verbose)
fprintf(stderr, "Server supports side-band\n");
use_sideband = 1;
}
if (!ref) {
packet_flush(fd[1]);
die("no matching remote head");
}
if (everything_local(&ref, nr_match, match)) {
packet_flush(fd[1]);
goto all_done;
}
if (find_common(fd, sha1, ref) < 0)
if (!args.keep_pack)
/* When cloning, it is not unusual to have
* no common commit.
*/
fprintf(stderr, "warning: no common commits\n");
if (get_pack(fd, pack_lockfile))
die("git-fetch-pack: fetch failed.");
all_done:
return ref;
}
static int remove_duplicates(int nr_heads, char **heads)
{
int src, dst;
for (src = dst = 0; src < nr_heads; src++) {
/* If heads[src] is different from any of
* heads[0..dst], push it in.
*/
int i;
for (i = 0; i < dst; i++) {
if (!strcmp(heads[i], heads[src]))
break;
}
if (i < dst)
continue;
if (src != dst)
heads[dst] = heads[src];
dst++;
}
return dst;
}
static int fetch_pack_config(const char *var, const char *value)
{
if (strcmp(var, "fetch.unpacklimit") == 0) {
fetch_unpack_limit = git_config_int(var, value);
return 0;
}
if (strcmp(var, "transfer.unpacklimit") == 0) {
transfer_unpack_limit = git_config_int(var, value);
return 0;
}
return git_default_config(var, value);
}
static struct lock_file lock;
static void fetch_pack_setup(void)
{
static int did_setup;
if (did_setup)
return;
git_config(fetch_pack_config);
if (0 <= transfer_unpack_limit)
unpack_limit = transfer_unpack_limit;
else if (0 <= fetch_unpack_limit)
unpack_limit = fetch_unpack_limit;
did_setup = 1;
}
int cmd_fetch_pack(int argc, const char **argv, const char *prefix)
{
int i, ret, nr_heads;
struct ref *ref;
char *dest = NULL, **heads;
nr_heads = 0;
heads = NULL;
for (i = 1; i < argc; i++) {
const char *arg = argv[i];
if (*arg == '-') {
if (!prefixcmp(arg, "--upload-pack=")) {
args.uploadpack = arg + 14;
continue;
}
if (!prefixcmp(arg, "--exec=")) {
args.uploadpack = arg + 7;
continue;
}
if (!strcmp("--quiet", arg) || !strcmp("-q", arg)) {
args.quiet = 1;
continue;
}
if (!strcmp("--keep", arg) || !strcmp("-k", arg)) {
args.lock_pack = args.keep_pack;
args.keep_pack = 1;
continue;
}
if (!strcmp("--thin", arg)) {
args.use_thin_pack = 1;
continue;
}
if (!strcmp("--all", arg)) {
args.fetch_all = 1;
continue;
}
if (!strcmp("-v", arg)) {
args.verbose = 1;
continue;
}
if (!prefixcmp(arg, "--depth=")) {
args.depth = strtol(arg + 8, NULL, 0);
continue;
}
if (!strcmp("--no-progress", arg)) {
args.no_progress = 1;
continue;
}
usage(fetch_pack_usage);
}
dest = (char *)arg;
heads = (char **)(argv + i + 1);
nr_heads = argc - i - 1;
break;
}
if (!dest)
usage(fetch_pack_usage);
ref = fetch_pack(&args, dest, nr_heads, heads, NULL);
ret = !ref;
while (ref) {
printf("%s %s\n",
sha1_to_hex(ref->old_sha1), ref->name);
ref = ref->next;
}
return ret;
}
struct ref *fetch_pack(struct fetch_pack_args *my_args,
const char *dest,
int nr_heads,
char **heads,
char **pack_lockfile)
{
int i, ret;
int fd[2];
struct child_process *conn;
struct ref *ref;
struct stat st;
fetch_pack_setup();
memcpy(&args, my_args, sizeof(args));
if (args.depth > 0) {
if (stat(git_path("shallow"), &st))
st.st_mtime = 0;
}
conn = git_connect(fd, (char *)dest, args.uploadpack,
args.verbose ? CONNECT_VERBOSE : 0);
if (heads && nr_heads)
nr_heads = remove_duplicates(nr_heads, heads);
ref = do_fetch_pack(fd, nr_heads, heads, pack_lockfile);
close(fd[0]);
close(fd[1]);
ret = finish_connect(conn);
if (!ret && nr_heads) {
/* If the heads to pull were given, we should have
* consumed all of them by matching the remote.
* Otherwise, 'git-fetch remote no-such-ref' would
* silently succeed without issuing an error.
*/
for (i = 0; i < nr_heads; i++)
if (heads[i] && heads[i][0]) {
error("no such remote ref %s", heads[i]);
ret = 1;
}
}
if (!ret && args.depth > 0) {
struct cache_time mtime;
char *shallow = git_path("shallow");
int fd;
mtime.sec = st.st_mtime;
#ifdef USE_NSEC
mtime.usec = st.st_mtim.usec;
#endif
if (stat(shallow, &st)) {
if (mtime.sec)
die("shallow file was removed during fetch");
} else if (st.st_mtime != mtime.sec
#ifdef USE_NSEC
|| st.st_mtim.usec != mtime.usec
#endif
)
die("shallow file was changed during fetch");
fd = hold_lock_file_for_update(&lock, shallow, 1);
if (!write_shallow_commits(fd, 0)) {
unlink(shallow);
rollback_lock_file(&lock);
} else {
close(fd);
commit_lock_file(&lock);
}
}
if (ret)
ref = NULL;
return ref;
}