Teach send-pack a mirror mode

[thirdparty/git.git] / builtin-send-pack.c

#include "cache.h"
#include "commit.h"
#include "tag.h"
#include "refs.h"
#include "pkt-line.h"
#include "run-command.h"
#include "remote.h"
#include "send-pack.h"

static const char send_pack_usage[] =
"git-send-pack [--all | --mirror] [--dry-run] [--force] [--receive-pack=<git-receive-pack>] [--verbose] [--thin] [<host>:]<directory> [<ref>...]\n"
"  --all and explicit <ref> specification are mutually exclusive.";

static struct send_pack_args args = {
	/* .receivepack = */ "git-receive-pack",
};

/*
 * Make a pack stream and spit it out into file descriptor fd
 */
static int pack_objects(int fd, struct ref *refs)
{
	/*
	 * The child becomes pack-objects --revs; we feed
	 * the revision parameters to it via its stdin and
	 * let its stdout go back to the other end.
	 */
	const char *argv[] = {
		"pack-objects",
		"--all-progress",
		"--revs",
		"--stdout",
		NULL,
		NULL,
	};
	struct child_process po;

	if (args.use_thin_pack)
		argv[4] = "--thin";
	memset(&po, 0, sizeof(po));
	po.argv = argv;
	po.in = -1;
	po.out = fd;
	po.git_cmd = 1;
	if (start_command(&po))
		die("git-pack-objects failed (%s)", strerror(errno));

	/*
	 * We feed the pack-objects we just spawned with revision
	 * parameters by writing to the pipe.
	 */
	while (refs) {
		char buf[42];

		if (!is_null_sha1(refs->old_sha1) &&
		    has_sha1_file(refs->old_sha1)) {
			memcpy(buf + 1, sha1_to_hex(refs->old_sha1), 40);
			buf[0] = '^';
			buf[41] = '\n';
			if (!write_or_whine(po.in, buf, 42,
						"send-pack: send refs"))
				break;
		}
		if (!is_null_sha1(refs->new_sha1)) {
			memcpy(buf, sha1_to_hex(refs->new_sha1), 40);
			buf[40] = '\n';
			if (!write_or_whine(po.in, buf, 41,
						"send-pack: send refs"))
				break;
		}
		refs = refs->next;
	}

	if (finish_command(&po))
		return error("pack-objects died with strange error");
	return 0;
}

static void unmark_and_free(struct commit_list *list, unsigned int mark)
{
	while (list) {
		struct commit_list *temp = list;
		temp->item->object.flags &= ~mark;
		list = temp->next;
		free(temp);
	}
}

static int ref_newer(const unsigned char *new_sha1,
		     const unsigned char *old_sha1)
{
	struct object *o;
	struct commit *old, *new;
	struct commit_list *list, *used;
	int found = 0;

	/* Both new and old must be commit-ish and new is descendant of
	 * old.  Otherwise we require --force.
	 */
	o = deref_tag(parse_object(old_sha1), NULL, 0);
	if (!o || o->type != OBJ_COMMIT)
		return 0;
	old = (struct commit *) o;

	o = deref_tag(parse_object(new_sha1), NULL, 0);
	if (!o || o->type != OBJ_COMMIT)
		return 0;
	new = (struct commit *) o;

	if (parse_commit(new) < 0)
		return 0;

	used = list = NULL;
	commit_list_insert(new, &list);
	while (list) {
		new = pop_most_recent_commit(&list, 1);
		commit_list_insert(new, &used);
		if (new == old) {
			found = 1;
			break;
		}
	}
	unmark_and_free(list, 1);
	unmark_and_free(used, 1);
	return found;
}

static struct ref *local_refs, **local_tail;
static struct ref *remote_refs, **remote_tail;

static int one_local_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
{
	struct ref *ref;
	int len = strlen(refname) + 1;
	ref = xcalloc(1, sizeof(*ref) + len);
	hashcpy(ref->new_sha1, sha1);
	memcpy(ref->name, refname, len);
	*local_tail = ref;
	local_tail = &ref->next;
	return 0;
}

static void get_local_heads(void)
{
	local_tail = &local_refs;
	for_each_ref(one_local_ref, NULL);
}

static int receive_status(int in)
{
	char line[1000];
	int ret = 0;
	int len = packet_read_line(in, line, sizeof(line));
	if (len < 10 || memcmp(line, "unpack ", 7)) {
		fprintf(stderr, "did not receive status back\n");
		return -1;
	}
	if (memcmp(line, "unpack ok\n", 10)) {
		fputs(line, stderr);
		ret = -1;
	}
	while (1) {
		len = packet_read_line(in, line, sizeof(line));
		if (!len)
			break;
		if (len < 3 ||
		    (memcmp(line, "ok", 2) && memcmp(line, "ng", 2))) {
			fprintf(stderr, "protocol error: %s\n", line);
			ret = -1;
			break;
		}
		if (!memcmp(line, "ok", 2))
			continue;
		fputs(line, stderr);
		ret = -1;
	}
	return ret;
}

static void update_tracking_ref(struct remote *remote, struct ref *ref)
{
	struct refspec rs;
	int will_delete_ref;

	rs.src = ref->name;
	rs.dst = NULL;

	if (!ref->peer_ref)
		return;

	will_delete_ref = is_null_sha1(ref->peer_ref->new_sha1);

	if (!will_delete_ref &&
			!hashcmp(ref->old_sha1, ref->peer_ref->new_sha1))
		return;

	if (!remote_find_tracking(remote, &rs)) {
		if (args.verbose)
			fprintf(stderr, "updating local tracking ref '%s'\n", rs.dst);
		if (is_null_sha1(ref->peer_ref->new_sha1)) {
			if (delete_ref(rs.dst, NULL))
				error("Failed to delete");
		} else
			update_ref("update by push", rs.dst,
					ref->new_sha1, NULL, 0, 0);
		free(rs.dst);
	}
}

static const char *prettify_ref(const char *name)
{
	return name + (
		!prefixcmp(name, "refs/heads/") ? 11 :
		!prefixcmp(name, "refs/tags/") ? 10 :
		!prefixcmp(name, "refs/remotes/") ? 13 :
		0);
}

#define SUMMARY_WIDTH (2 * DEFAULT_ABBREV + 3)

static int do_send_pack(int in, int out, struct remote *remote, const char *dest, int nr_refspec, const char **refspec)
{
	struct ref *ref;
	int new_refs;
	int ret = 0;
	int ask_for_status_report = 0;
	int allow_deleting_refs = 0;
	int expect_status_report = 0;
	int shown_dest = 0;
	int flags = MATCH_REFS_NONE;

	if (args.send_all)
		flags |= MATCH_REFS_ALL;
	if (args.send_mirror)
		flags |= MATCH_REFS_MIRROR;

	/* No funny business with the matcher */
	remote_tail = get_remote_heads(in, &remote_refs, 0, NULL, REF_NORMAL);
	get_local_heads();

	/* Does the other end support the reporting? */
	if (server_supports("report-status"))
		ask_for_status_report = 1;
	if (server_supports("delete-refs"))
		allow_deleting_refs = 1;

	/* match them up */
	if (!remote_tail)
		remote_tail = &remote_refs;
	if (match_refs(local_refs, remote_refs, &remote_tail,
					       nr_refspec, refspec, flags))
		return -1;

	if (!remote_refs) {
		fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
			"Perhaps you should specify a branch such as 'master'.\n");
		return 0;
	}

	/*
	 * Finally, tell the other end!
	 */
	new_refs = 0;
	for (ref = remote_refs; ref; ref = ref->next) {
		char old_hex[60], *new_hex;
		int will_delete_ref;
		const char *pretty_ref;
		const char *pretty_peer = NULL; /* only used when not deleting */
		const unsigned char *new_sha1;

		if (!ref->peer_ref) {
			if (!args.send_mirror)
				continue;
			new_sha1 = null_sha1;
		}
		else
			new_sha1 = ref->peer_ref->new_sha1;

		if (!shown_dest) {
			fprintf(stderr, "To %s\n", dest);
			shown_dest = 1;
		}

		will_delete_ref = is_null_sha1(new_sha1);

		pretty_ref = prettify_ref(ref->name);
		if (!will_delete_ref)
			pretty_peer = prettify_ref(ref->peer_ref->name);

		if (will_delete_ref && !allow_deleting_refs) {
			fprintf(stderr, " ! %-*s %s (remote does not support deleting refs)\n",
					SUMMARY_WIDTH, "[rejected]", pretty_ref);
			ret = -2;
			continue;
		}
		if (!will_delete_ref &&
		    !hashcmp(ref->old_sha1, new_sha1)) {
			if (args.verbose)
				fprintf(stderr, " = %-*s %s -> %s\n",
					SUMMARY_WIDTH, "[up to date]",
					pretty_peer, pretty_ref);
			continue;
		}

		/* This part determines what can overwrite what.
		 * The rules are:
		 *
		 * (0) you can always use --force or +A:B notation to
		 *     selectively force individual ref pairs.
		 *
		 * (1) if the old thing does not exist, it is OK.
		 *
		 * (2) if you do not have the old thing, you are not allowed
		 *     to overwrite it; you would not know what you are losing
		 *     otherwise.
		 *
		 * (3) if both new and old are commit-ish, and new is a
		 *     descendant of old, it is OK.
		 *
		 * (4) regardless of all of the above, removing :B is
		 *     always allowed.
		 */

		if (!args.force_update &&
		    !will_delete_ref &&
		    !is_null_sha1(ref->old_sha1) &&
		    !ref->force) {
			if (!has_sha1_file(ref->old_sha1) ||
			    !ref_newer(new_sha1, ref->old_sha1)) {
				/* We do not have the remote ref, or
				 * we know that the remote ref is not
				 * an ancestor of what we are trying to
				 * push.  Either way this can be losing
				 * commits at the remote end and likely
				 * we were not up to date to begin with.
				 */
				fprintf(stderr, " ! %-*s %s -> %s (non-fast forward)\n",
						SUMMARY_WIDTH, "[rejected]",
						pretty_peer, pretty_ref);
				ret = -2;
				continue;
			}
		}
		hashcpy(ref->new_sha1, new_sha1);
		if (!will_delete_ref)
			new_refs++;
		strcpy(old_hex, sha1_to_hex(ref->old_sha1));
		new_hex = sha1_to_hex(ref->new_sha1);

		if (!args.dry_run) {
			if (ask_for_status_report) {
				packet_write(out, "%s %s %s%c%s",
					old_hex, new_hex, ref->name, 0,
					"report-status");
				ask_for_status_report = 0;
				expect_status_report = 1;
			}
			else
				packet_write(out, "%s %s %s",
					old_hex, new_hex, ref->name);
		}
		if (will_delete_ref)
			fprintf(stderr, " - %-*s %s\n",
				SUMMARY_WIDTH, "[deleting]",
				pretty_ref);
		else if (is_null_sha1(ref->old_sha1)) {
			const char *msg;

			if (!prefixcmp(ref->name, "refs/tags/"))
				msg = "[new tag]";
			else
				msg = "[new branch]";
			fprintf(stderr, " * %-*s %s -> %s\n",
				SUMMARY_WIDTH, msg,
				pretty_peer, pretty_ref);
		}
		else {
			char quickref[83];
			char type = ' ';
			const char *msg = "";
			const char *old_abb;
			old_abb = find_unique_abbrev(ref->old_sha1, DEFAULT_ABBREV);
			strcpy(quickref, old_abb ? old_abb : old_hex);
			if (ref_newer(ref->peer_ref->new_sha1, ref->old_sha1))
				strcat(quickref, "..");
			else {
				strcat(quickref, "...");
				type = '+';
				msg = " (forced update)";
			}
			strcat(quickref, find_unique_abbrev(ref->new_sha1, DEFAULT_ABBREV));

			fprintf(stderr, " %c %-*s %s -> %s%s\n",
				type,
				SUMMARY_WIDTH, quickref,
				pretty_peer, pretty_ref,
				msg);
		}
	}

	packet_flush(out);
	if (new_refs && !args.dry_run)
		ret = pack_objects(out, remote_refs);
	close(out);

	if (expect_status_report) {
		if (receive_status(in))
			ret = -4;
	}

	if (!args.dry_run && remote && ret == 0) {
		for (ref = remote_refs; ref; ref = ref->next)
			update_tracking_ref(remote, ref);
	}

	if (!new_refs && ret == 0)
		fprintf(stderr, "Everything up-to-date\n");
	return ret;
}

static void verify_remote_names(int nr_heads, const char **heads)
{
	int i;

	for (i = 0; i < nr_heads; i++) {
		const char *remote = strchr(heads[i], ':');

		remote = remote ? (remote + 1) : heads[i];
		switch (check_ref_format(remote)) {
		case 0: /* ok */
		case -2: /* ok but a single level -- that is fine for
			  * a match pattern.
			  */
		case -3: /* ok but ends with a pattern-match character */
			continue;
		}
		die("remote part of refspec is not a valid name in %s",
		    heads[i]);
	}
}

int cmd_send_pack(int argc, const char **argv, const char *prefix)
{
	int i, nr_heads = 0;
	const char **heads = NULL;
	const char *remote_name = NULL;
	struct remote *remote = NULL;
	const char *dest = NULL;

	argv++;
	for (i = 1; i < argc; i++, argv++) {
		const char *arg = *argv;

		if (*arg == '-') {
			if (!prefixcmp(arg, "--receive-pack=")) {
				args.receivepack = arg + 15;
				continue;
			}
			if (!prefixcmp(arg, "--exec=")) {
				args.receivepack = arg + 7;
				continue;
			}
			if (!prefixcmp(arg, "--remote=")) {
				remote_name = arg + 9;
				continue;
			}
			if (!strcmp(arg, "--all")) {
				args.send_all = 1;
				continue;
			}
			if (!strcmp(arg, "--dry-run")) {
				args.dry_run = 1;
				continue;
			}
			if (!strcmp(arg, "--mirror")) {
				args.send_mirror = 1;
				continue;
			}
			if (!strcmp(arg, "--force")) {
				args.force_update = 1;
				continue;
			}
			if (!strcmp(arg, "--verbose")) {
				args.verbose = 1;
				continue;
			}
			if (!strcmp(arg, "--thin")) {
				args.use_thin_pack = 1;
				continue;
			}
			usage(send_pack_usage);
		}
		if (!dest) {
			dest = arg;
			continue;
		}
		heads = (const char **) argv;
		nr_heads = argc - i;
		break;
	}
	if (!dest)
		usage(send_pack_usage);
	/*
	 * --all and --mirror are incompatible; neither makes sense
	 * with any refspecs.
	 */
	if ((heads && (args.send_all || args.send_mirror)) ||
					(args.send_all && args.send_mirror))
		usage(send_pack_usage);

	if (remote_name) {
		remote = remote_get(remote_name);
		if (!remote_has_url(remote, dest)) {
			die("Destination %s is not a uri for %s",
			    dest, remote_name);
		}
	}

	return send_pack(&args, dest, remote, nr_heads, heads);
}

int send_pack(struct send_pack_args *my_args,
	      const char *dest, struct remote *remote,
	      int nr_heads, const char **heads)
{
	int fd[2], ret;
	struct child_process *conn;

	memcpy(&args, my_args, sizeof(args));

	verify_remote_names(nr_heads, heads);

	conn = git_connect(fd, dest, args.receivepack, args.verbose ? CONNECT_VERBOSE : 0);
	ret = do_send_pack(fd[0], fd[1], remote, dest, nr_heads, heads);
	close(fd[0]);
	close(fd[1]);
	ret |= finish_connect(conn);
	return !!ret;
}