git/fetch-pack.c

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8.9 KiB
C
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#include "cache.h"
#include "refs.h"
#include "pkt-line.h"
#include "commit.h"
#include "tag.h"
#include <time.h>
#include <sys/wait.h>
static int quiet;
static int verbose;
static const char fetch_pack_usage[] =
"git-fetch-pack [-q] [-v] [--exec=upload-pack] [host:]directory <refs>...";
static const char *exec = "git-upload-pack";
#define COMPLETE (1U << 0)
#define COMMON (1U << 1)
#define COMMON_REF (1U << 2 | COMMON)
#define SEEN (1U << 3)
#define POPPED (1U << 4)
static struct commit_list *rev_list = NULL;
static struct commit_list *rev_list_end = NULL;
static unsigned long non_common_revs = 0;
static void rev_list_append(struct commit *commit, int mark)
{
if (!(commit->object.flags & mark)) {
commit->object.flags |= mark;
if (rev_list == NULL) {
commit_list_insert(commit, &rev_list);
rev_list_end = rev_list;
} else {
commit_list_insert(commit, &(rev_list_end->next));
rev_list_end = rev_list_end->next;
}
if (!(commit->object.flags & COMMON))
non_common_revs++;
}
}
static int rev_list_append_sha1(const char *path, const unsigned char *sha1)
{
struct object *o = deref_tag(parse_object(sha1));
if (o->type == commit_type)
rev_list_append((struct commit *)o, SEEN);
return 0;
}
static void mark_common(struct commit *commit)
{
if (commit != NULL && !(commit->object.flags & COMMON)) {
struct object *o = (struct object *)commit;
o->flags |= COMMON;
if (!(o->flags & SEEN))
rev_list_append(commit, SEEN);
else {
struct commit_list *parents;
if (!(o->flags & POPPED))
non_common_revs--;
if (!o->parsed)
parse_commit(commit);
for (parents = commit->parents;
parents;
parents = parents->next)
mark_common(parents->item);
}
}
}
/*
Get the next rev to send, ignoring the common.
*/
static const unsigned char* get_rev()
{
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 (mark & COMMON)
mark_common(parents->item);
else
rev_list_append(parents->item, mark);
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, multi_ack = 0, retval;
const unsigned char *sha1;
for_each_ref(rev_list_append_sha1);
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)) {
o = deref_tag(o);
if (o->type == commit_type)
rev_list_append((struct commit *)o,
COMMON_REF | SEEN);
continue;
}
packet_write(fd[1], "want %s multi_ack\n", sha1_to_hex(remote));
fetching++;
}
packet_flush(fd[1]);
if (!fetching)
return 1;
flushes = 0;
retval = -1;
while ((sha1 = get_rev())) {
packet_write(fd[1], "have %s\n", sha1_to_hex(sha1));
if (verbose)
fprintf(stderr, "have %s\n", sha1_to_hex(sha1));
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 (verbose && ack)
fprintf(stderr, "got ack %d %s\n", ack,
sha1_to_hex(result_sha1));
if (ack == 1) {
if (!multi_ack)
flushes = 0;
retval = 0;
goto done;
} else if (ack == 2) {
multi_ack = 1;
mark_common((struct commit *)
lookup_object(result_sha1));
retval = 0;
}
} while(ack);
flushes--;
}
}
done:
if (multi_ack) {
packet_flush(fd[1]);
flushes++;
}
packet_write(fd[1], "done\n");
if (verbose)
fprintf(stderr, "done\n");
if (retval != 0)
flushes++;
while (flushes) {
if (get_ack(fd[0], result_sha1)) {
if (verbose)
fprintf(stderr, "got ack %s\n",
sha1_to_hex(result_sha1));
if (!multi_ack)
return 0;
retval = 0;
continue;
}
flushes--;
}
return retval;
}
static struct commit_list *complete = NULL;
static int mark_complete(const char *path, const unsigned char *sha1)
{
struct object *o = parse_object(sha1);
while (o && o->type == tag_type) {
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 == commit_type) {
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 (verbose)
fprintf(stderr, "Marking %s as complete\n",
sha1_to_hex(complete->item->object.sha1));
pop_most_recent_commit(&complete, COMPLETE);
}
}
static int everything_local(struct ref *refs)
{
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 == commit_type) {
struct commit *commit = (struct commit *)o;
if (!cutoff || cutoff < commit->date)
cutoff = commit->date;
}
}
for_each_ref(mark_complete);
if (cutoff)
mark_recent_complete_commits(cutoff);
for (retval = 1; refs ; refs = refs->next) {
const unsigned char *remote = refs->old_sha1;
unsigned char local[20];
struct object *o;
o = parse_object(remote);
if (!o || !(o->flags & COMPLETE)) {
retval = 0;
if (!verbose)
continue;
fprintf(stderr,
"want %s (%s)\n", sha1_to_hex(remote),
refs->name);
continue;
}
memcpy(refs->new_sha1, local, 20);
if (!verbose)
continue;
fprintf(stderr,
"already have %s (%s)\n", sha1_to_hex(remote),
refs->name);
}
return retval;
}
static int fetch_pack(int fd[2], int nr_match, char **match)
{
struct ref *ref;
unsigned char sha1[20];
int status;
pid_t pid;
get_remote_heads(fd[0], &ref, nr_match, match, 1);
if (!ref) {
packet_flush(fd[1]);
die("no matching remote head");
}
if (everything_local(ref)) {
packet_flush(fd[1]);
goto all_done;
}
if (find_common(fd, sha1, ref) < 0)
fprintf(stderr, "warning: no common commits\n");
pid = fork();
if (pid < 0)
die("git-fetch-pack: unable to fork off git-unpack-objects");
if (!pid) {
dup2(fd[0], 0);
close(fd[0]);
close(fd[1]);
execlp("git-unpack-objects", "git-unpack-objects",
quiet ? "-q" : NULL, NULL);
die("git-unpack-objects exec failed");
}
close(fd[0]);
close(fd[1]);
while (waitpid(pid, &status, 0) < 0) {
if (errno != EINTR)
die("waiting for git-unpack-objects: %s", strerror(errno));
}
if (WIFEXITED(status)) {
int code = WEXITSTATUS(status);
if (code)
die("git-unpack-objects died with error code %d", code);
all_done:
while (ref) {
printf("%s %s\n",
sha1_to_hex(ref->old_sha1), ref->name);
ref = ref->next;
}
return 0;
}
if (WIFSIGNALED(status)) {
int sig = WTERMSIG(status);
die("git-unpack-objects died of signal %d", sig);
}
die("Sherlock Holmes! git-unpack-objects died of unnatural causes %d!", status);
}
int main(int argc, char **argv)
{
int i, ret, nr_heads;
char *dest = NULL, **heads;
int fd[2];
pid_t pid;
nr_heads = 0;
heads = NULL;
for (i = 1; i < argc; i++) {
char *arg = argv[i];
if (*arg == '-') {
if (!strncmp("--exec=", arg, 7)) {
exec = arg + 7;
continue;
}
if (!strcmp("-q", arg)) {
quiet = 1;
continue;
}
if (!strcmp("-v", arg)) {
verbose = 1;
continue;
}
usage(fetch_pack_usage);
}
dest = arg;
heads = argv + i + 1;
nr_heads = argc - i - 1;
break;
}
if (!dest)
usage(fetch_pack_usage);
pid = git_connect(fd, dest, exec);
if (pid < 0)
return 1;
ret = fetch_pack(fd, nr_heads, heads);
close(fd[0]);
close(fd[1]);
finish_connect(pid);
return ret;
}