git/transport.c

#include "cache.h"
#include "transport.h"
#include "run-command.h"
#ifndef NO_CURL
#include "http.h"
#endif
#include "pkt-line.h"
#include "fetch-pack.h"
#include "send-pack.h"
#include "walker.h"
#include "bundle.h"
#include "dir.h"
#include "refs.h"

/* rsync support */

/*
 * We copy packed-refs and refs/ into a temporary file, then read the
 * loose refs recursively (sorting whenever possible), and then inserting
 * those packed refs that are not yet in the list (not validating, but
 * assuming that the file is sorted).
 *
 * Appears refactoring this from refs.c is too cumbersome.
 */

static int str_cmp(const void *a, const void *b)
{
	const char *s1 = a;
	const char *s2 = b;

	return strcmp(s1, s2);
}

/* path->buf + name_offset is expected to point to "refs/" */

static int read_loose_refs(struct strbuf *path, int name_offset,
		struct ref **tail)
{
	DIR *dir = opendir(path->buf);
	struct dirent *de;
	struct {
		char **entries;
		int nr, alloc;
	} list;
	int i, pathlen;

	if (!dir)
		return -1;

	memset (&list, 0, sizeof(list));

	while ((de = readdir(dir))) {
		if (is_dot_or_dotdot(de->d_name))
			continue;
		ALLOC_GROW(list.entries, list.nr + 1, list.alloc);
		list.entries[list.nr++] = xstrdup(de->d_name);
	}
	closedir(dir);

	/* sort the list */

	qsort(list.entries, list.nr, sizeof(char *), str_cmp);

	pathlen = path->len;
	strbuf_addch(path, '/');

	for (i = 0; i < list.nr; i++, strbuf_setlen(path, pathlen + 1)) {
		strbuf_addstr(path, list.entries[i]);
		if (read_loose_refs(path, name_offset, tail)) {
			int fd = open(path->buf, O_RDONLY);
			char buffer[40];
			struct ref *next;

			if (fd < 0)
				continue;
			next = alloc_ref(path->buf + name_offset);
			if (read_in_full(fd, buffer, 40) != 40 ||
					get_sha1_hex(buffer, next->old_sha1)) {
				close(fd);
				free(next);
				continue;
			}
			close(fd);
			(*tail)->next = next;
			*tail = next;
		}
	}
	strbuf_setlen(path, pathlen);

	for (i = 0; i < list.nr; i++)
		free(list.entries[i]);
	free(list.entries);

	return 0;
}

/* insert the packed refs for which no loose refs were found */

static void insert_packed_refs(const char *packed_refs, struct ref **list)
{
	FILE *f = fopen(packed_refs, "r");
	static char buffer[PATH_MAX];

	if (!f)
		return;

	for (;;) {
		int cmp = cmp, len;

		if (!fgets(buffer, sizeof(buffer), f)) {
			fclose(f);
			return;
		}

		if (hexval(buffer[0]) > 0xf)
			continue;
		len = strlen(buffer);
		if (len && buffer[len - 1] == '\n')
			buffer[--len] = '\0';
		if (len < 41)
			continue;
		while ((*list)->next &&
				(cmp = strcmp(buffer + 41,
				      (*list)->next->name)) > 0)
			list = &(*list)->next;
		if (!(*list)->next || cmp < 0) {
			struct ref *next = alloc_ref(buffer + 41);
			buffer[40] = '\0';
			if (get_sha1_hex(buffer, next->old_sha1)) {
				warning ("invalid SHA-1: %s", buffer);
				free(next);
				continue;
			}
			next->next = (*list)->next;
			(*list)->next = next;
			list = &(*list)->next;
		}
	}
}

static const char *rsync_url(const char *url)
{
	return prefixcmp(url, "rsync://") ? skip_prefix(url, "rsync:") : url;
}

static struct ref *get_refs_via_rsync(struct transport *transport, int for_push)
{
	struct strbuf buf = STRBUF_INIT, temp_dir = STRBUF_INIT;
	struct ref dummy, *tail = &dummy;
	struct child_process rsync;
	const char *args[5];
	int temp_dir_len;

	if (for_push)
		return NULL;

	/* copy the refs to the temporary directory */

	strbuf_addstr(&temp_dir, git_path("rsync-refs-XXXXXX"));
	if (!mkdtemp(temp_dir.buf))
		die ("Could not make temporary directory");
	temp_dir_len = temp_dir.len;

	strbuf_addstr(&buf, rsync_url(transport->url));
	strbuf_addstr(&buf, "/refs");

	memset(&rsync, 0, sizeof(rsync));
	rsync.argv = args;
	rsync.stdout_to_stderr = 1;
	args[0] = "rsync";
	args[1] = (transport->verbose > 0) ? "-rv" : "-r";
	args[2] = buf.buf;
	args[3] = temp_dir.buf;
	args[4] = NULL;

	if (run_command(&rsync))
		die ("Could not run rsync to get refs");

	strbuf_reset(&buf);
	strbuf_addstr(&buf, rsync_url(transport->url));
	strbuf_addstr(&buf, "/packed-refs");

	args[2] = buf.buf;

	if (run_command(&rsync))
		die ("Could not run rsync to get refs");

	/* read the copied refs */

	strbuf_addstr(&temp_dir, "/refs");
	read_loose_refs(&temp_dir, temp_dir_len + 1, &tail);
	strbuf_setlen(&temp_dir, temp_dir_len);

	tail = &dummy;
	strbuf_addstr(&temp_dir, "/packed-refs");
	insert_packed_refs(temp_dir.buf, &tail);
	strbuf_setlen(&temp_dir, temp_dir_len);

	if (remove_dir_recursively(&temp_dir, 0))
		warning ("Error removing temporary directory %s.",
				temp_dir.buf);

	strbuf_release(&buf);
	strbuf_release(&temp_dir);

	return dummy.next;
}

static int fetch_objs_via_rsync(struct transport *transport,
				int nr_objs, const struct ref **to_fetch)
{
	struct strbuf buf = STRBUF_INIT;
	struct child_process rsync;
	const char *args[8];
	int result;

	strbuf_addstr(&buf, rsync_url(transport->url));
	strbuf_addstr(&buf, "/objects/");

	memset(&rsync, 0, sizeof(rsync));
	rsync.argv = args;
	rsync.stdout_to_stderr = 1;
	args[0] = "rsync";
	args[1] = (transport->verbose > 0) ? "-rv" : "-r";
	args[2] = "--ignore-existing";
	args[3] = "--exclude";
	args[4] = "info";
	args[5] = buf.buf;
	args[6] = get_object_directory();
	args[7] = NULL;

	/* NEEDSWORK: handle one level of alternates */
	result = run_command(&rsync);

	strbuf_release(&buf);

	return result;
}

static int write_one_ref(const char *name, const unsigned char *sha1,
		int flags, void *data)
{
	struct strbuf *buf = data;
	int len = buf->len;
	FILE *f;

	/* when called via for_each_ref(), flags is non-zero */
	if (flags && prefixcmp(name, "refs/heads/") &&
			prefixcmp(name, "refs/tags/"))
		return 0;

	strbuf_addstr(buf, name);
	if (safe_create_leading_directories(buf->buf) ||
			!(f = fopen(buf->buf, "w")) ||
			fprintf(f, "%s\n", sha1_to_hex(sha1)) < 0 ||
			fclose(f))
		return error("problems writing temporary file %s", buf->buf);
	strbuf_setlen(buf, len);
	return 0;
}

static int write_refs_to_temp_dir(struct strbuf *temp_dir,
		int refspec_nr, const char **refspec)
{
	int i;

	for (i = 0; i < refspec_nr; i++) {
		unsigned char sha1[20];
		char *ref;

		if (dwim_ref(refspec[i], strlen(refspec[i]), sha1, &ref) != 1)
			return error("Could not get ref %s", refspec[i]);

		if (write_one_ref(ref, sha1, 0, temp_dir)) {
			free(ref);
			return -1;
		}
		free(ref);
	}
	return 0;
}

static int rsync_transport_push(struct transport *transport,
		int refspec_nr, const char **refspec, int flags)
{
	struct strbuf buf = STRBUF_INIT, temp_dir = STRBUF_INIT;
	int result = 0, i;
	struct child_process rsync;
	const char *args[10];

	if (flags & TRANSPORT_PUSH_MIRROR)
		return error("rsync transport does not support mirror mode");

	/* first push the objects */

	strbuf_addstr(&buf, rsync_url(transport->url));
	strbuf_addch(&buf, '/');

	memset(&rsync, 0, sizeof(rsync));
	rsync.argv = args;
	rsync.stdout_to_stderr = 1;
	i = 0;
	args[i++] = "rsync";
	args[i++] = "-a";
	if (flags & TRANSPORT_PUSH_DRY_RUN)
		args[i++] = "--dry-run";
	if (transport->verbose > 0)
		args[i++] = "-v";
	args[i++] = "--ignore-existing";
	args[i++] = "--exclude";
	args[i++] = "info";
	args[i++] = get_object_directory();
	args[i++] = buf.buf;
	args[i++] = NULL;

	if (run_command(&rsync))
		return error("Could not push objects to %s",
				rsync_url(transport->url));

	/* copy the refs to the temporary directory; they could be packed. */

	strbuf_addstr(&temp_dir, git_path("rsync-refs-XXXXXX"));
	if (!mkdtemp(temp_dir.buf))
		die ("Could not make temporary directory");
	strbuf_addch(&temp_dir, '/');

	if (flags & TRANSPORT_PUSH_ALL) {
		if (for_each_ref(write_one_ref, &temp_dir))
			return -1;
	} else if (write_refs_to_temp_dir(&temp_dir, refspec_nr, refspec))
		return -1;

	i = 2;
	if (flags & TRANSPORT_PUSH_DRY_RUN)
		args[i++] = "--dry-run";
	if (!(flags & TRANSPORT_PUSH_FORCE))
		args[i++] = "--ignore-existing";
	args[i++] = temp_dir.buf;
	args[i++] = rsync_url(transport->url);
	args[i++] = NULL;
	if (run_command(&rsync))
		result = error("Could not push to %s",
				rsync_url(transport->url));

	if (remove_dir_recursively(&temp_dir, 0))
		warning ("Could not remove temporary directory %s.",
				temp_dir.buf);

	strbuf_release(&buf);
	strbuf_release(&temp_dir);

	return result;
}

/* Generic functions for using commit walkers */

#ifndef NO_CURL /* http fetch is the only user */
static int fetch_objs_via_walker(struct transport *transport,
				 int nr_objs, const struct ref **to_fetch)
{
	char *dest = xstrdup(transport->url);
	struct walker *walker = transport->data;
	char **objs = xmalloc(nr_objs * sizeof(*objs));
	int i;

	walker->get_all = 1;
	walker->get_tree = 1;
	walker->get_history = 1;
	walker->get_verbosely = transport->verbose >= 0;
	walker->get_recover = 0;

	for (i = 0; i < nr_objs; i++)
		objs[i] = xstrdup(sha1_to_hex(to_fetch[i]->old_sha1));

	if (walker_fetch(walker, nr_objs, objs, NULL, NULL))
		die("Fetch failed.");

	for (i = 0; i < nr_objs; i++)
		free(objs[i]);
	free(objs);
	free(dest);
	return 0;
}
#endif /* NO_CURL */

static int disconnect_walker(struct transport *transport)
{
	struct walker *walker = transport->data;
	if (walker)
		walker_free(walker);
	return 0;
}

#ifndef NO_CURL
static int curl_transport_push(struct transport *transport, int refspec_nr, const char **refspec, int flags)
{
	const char **argv;
	int argc;
	int err;

	if (flags & TRANSPORT_PUSH_MIRROR)
		return error("http transport does not support mirror mode");

	argv = xmalloc((refspec_nr + 12) * sizeof(char *));
	argv[0] = "http-push";
	argc = 1;
	if (flags & TRANSPORT_PUSH_ALL)
		argv[argc++] = "--all";
	if (flags & TRANSPORT_PUSH_FORCE)
		argv[argc++] = "--force";
	if (flags & TRANSPORT_PUSH_DRY_RUN)
		argv[argc++] = "--dry-run";
	if (flags & TRANSPORT_PUSH_VERBOSE)
		argv[argc++] = "--verbose";
	argv[argc++] = transport->url;
	while (refspec_nr--)
		argv[argc++] = *refspec++;
	argv[argc] = NULL;
	err = run_command_v_opt(argv, RUN_GIT_CMD);
	switch (err) {
	case -ERR_RUN_COMMAND_FORK:
		error("unable to fork for %s", argv[0]);
	case -ERR_RUN_COMMAND_EXEC:
		error("unable to exec %s", argv[0]);
		break;
	case -ERR_RUN_COMMAND_WAITPID:
	case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
	case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
	case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
		error("%s died with strange error", argv[0]);
	}
	return !!err;
}

static struct ref *get_refs_via_curl(struct transport *transport, int for_push)
{
	struct strbuf buffer = STRBUF_INIT;
	char *data, *start, *mid;
	char *ref_name;
	char *refs_url;
	int i = 0;

	struct active_request_slot *slot;
	struct slot_results results;

	struct ref *refs = NULL;
	struct ref *ref = NULL;
	struct ref *last_ref = NULL;

	struct walker *walker;

	if (for_push)
		return NULL;

	if (!transport->data)
		transport->data = get_http_walker(transport->url,
						transport->remote);

	walker = transport->data;

	refs_url = xmalloc(strlen(transport->url) + 11);
	sprintf(refs_url, "%s/info/refs", transport->url);

	slot = get_active_slot();
	slot->results = &results;
	curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
	curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
	curl_easy_setopt(slot->curl, CURLOPT_URL, refs_url);
	curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);

	if (start_active_slot(slot)) {
		run_active_slot(slot);
		if (results.curl_result != CURLE_OK) {
			strbuf_release(&buffer);
			if (missing_target(&results))
				die("%s not found: did you run git update-server-info on the server?", refs_url);
			else
				die("%s download error - %s", refs_url, curl_errorstr);
		}
	} else {
		strbuf_release(&buffer);
		die("Unable to start HTTP request");
	}

	data = buffer.buf;
	start = NULL;
	mid = data;
	while (i < buffer.len) {
		if (!start)
			start = &data[i];
		if (data[i] == '\t')
			mid = &data[i];
		if (data[i] == '\n') {
			data[i] = 0;
			ref_name = mid + 1;
			ref = xmalloc(sizeof(struct ref) +
				      strlen(ref_name) + 1);
			memset(ref, 0, sizeof(struct ref));
			strcpy(ref->name, ref_name);
			get_sha1_hex(start, ref->old_sha1);
			if (!refs)
				refs = ref;
			if (last_ref)
				last_ref->next = ref;
			last_ref = ref;
			start = NULL;
		}
		i++;
	}

	strbuf_release(&buffer);

	ref = alloc_ref("HEAD");
	if (!walker->fetch_ref(walker, ref) &&
	    !resolve_remote_symref(ref, refs)) {
		ref->next = refs;
		refs = ref;
	} else {
		free(ref);
	}

	return refs;
}

static int fetch_objs_via_curl(struct transport *transport,
				 int nr_objs, const struct ref **to_fetch)
{
	if (!transport->data)
		transport->data = get_http_walker(transport->url,
						transport->remote);
	return fetch_objs_via_walker(transport, nr_objs, to_fetch);
}

#endif

struct bundle_transport_data {
	int fd;
	struct bundle_header header;
};

static struct ref *get_refs_from_bundle(struct transport *transport, int for_push)
{
	struct bundle_transport_data *data = transport->data;
	struct ref *result = NULL;
	int i;

	if (for_push)
		return NULL;

	if (data->fd > 0)
		close(data->fd);
	data->fd = read_bundle_header(transport->url, &data->header);
	if (data->fd < 0)
		die ("Could not read bundle '%s'.", transport->url);
	for (i = 0; i < data->header.references.nr; i++) {
		struct ref_list_entry *e = data->header.references.list + i;
		struct ref *ref = alloc_ref(e->name);
		hashcpy(ref->old_sha1, e->sha1);
		ref->next = result;
		result = ref;
	}
	return result;
}

static int fetch_refs_from_bundle(struct transport *transport,
			       int nr_heads, const struct ref **to_fetch)
{
	struct bundle_transport_data *data = transport->data;
	return unbundle(&data->header, data->fd);
}

static int close_bundle(struct transport *transport)
{
	struct bundle_transport_data *data = transport->data;
	if (data->fd > 0)
		close(data->fd);
	free(data);
	return 0;
}

struct git_transport_data {
	unsigned thin : 1;
	unsigned keep : 1;
	unsigned followtags : 1;
	int depth;
	struct child_process *conn;
	int fd[2];
	const char *uploadpack;
	const char *receivepack;
	struct extra_have_objects extra_have;
};

static int set_git_option(struct transport *connection,
			  const char *name, const char *value)
{
	struct git_transport_data *data = connection->data;
	if (!strcmp(name, TRANS_OPT_UPLOADPACK)) {
		data->uploadpack = value;
		return 0;
	} else if (!strcmp(name, TRANS_OPT_RECEIVEPACK)) {
		data->receivepack = value;
		return 0;
	} else if (!strcmp(name, TRANS_OPT_THIN)) {
		data->thin = !!value;
		return 0;
	} else if (!strcmp(name, TRANS_OPT_FOLLOWTAGS)) {
		data->followtags = !!value;
		return 0;
	} else if (!strcmp(name, TRANS_OPT_KEEP)) {
		data->keep = !!value;
		return 0;
	} else if (!strcmp(name, TRANS_OPT_DEPTH)) {
		if (!value)
			data->depth = 0;
		else
			data->depth = atoi(value);
		return 0;
	}
	return 1;
}

static int connect_setup(struct transport *transport, int for_push, int verbose)
{
	struct git_transport_data *data = transport->data;
	data->conn = git_connect(data->fd, transport->url,
				 for_push ? data->receivepack : data->uploadpack,
				 verbose ? CONNECT_VERBOSE : 0);
	return 0;
}

static struct ref *get_refs_via_connect(struct transport *transport, int for_push)
{
	struct git_transport_data *data = transport->data;
	struct ref *refs;

	connect_setup(transport, for_push, 0);
	get_remote_heads(data->fd[0], &refs, 0, NULL,
			 for_push ? REF_NORMAL : 0, &data->extra_have);

	return refs;
}

static int fetch_refs_via_pack(struct transport *transport,
			       int nr_heads, const struct ref **to_fetch)
{
	struct git_transport_data *data = transport->data;
	char **heads = xmalloc(nr_heads * sizeof(*heads));
	char **origh = xmalloc(nr_heads * sizeof(*origh));
	const struct ref *refs;
	char *dest = xstrdup(transport->url);
	struct fetch_pack_args args;
	int i;
	struct ref *refs_tmp = NULL;

	memset(&args, 0, sizeof(args));
	args.uploadpack = data->uploadpack;
	args.keep_pack = data->keep;
	args.lock_pack = 1;
	args.use_thin_pack = data->thin;
	args.include_tag = data->followtags;
	args.verbose = (transport->verbose > 0);
	args.quiet = (transport->verbose < 0);
	args.no_progress = args.quiet || (!transport->progress && !isatty(1));
	args.depth = data->depth;

	for (i = 0; i < nr_heads; i++)
		origh[i] = heads[i] = xstrdup(to_fetch[i]->name);

	if (!data->conn) {
		connect_setup(transport, 0, 0);
		get_remote_heads(data->fd[0], &refs_tmp, 0, NULL, 0, NULL);
	}

	refs = fetch_pack(&args, data->fd, data->conn,
			  refs_tmp ? refs_tmp : transport->remote_refs,
			  dest, nr_heads, heads, &transport->pack_lockfile);
	close(data->fd[0]);
	close(data->fd[1]);
	if (finish_connect(data->conn))
		refs = NULL;
	data->conn = NULL;

	free_refs(refs_tmp);

	for (i = 0; i < nr_heads; i++)
		free(origh[i]);
	free(origh);
	free(heads);
	free(dest);
	return (refs ? 0 : -1);
}

static int refs_pushed(struct ref *ref)
{
	for (; ref; ref = ref->next) {
		switch(ref->status) {
		case REF_STATUS_NONE:
		case REF_STATUS_UPTODATE:
			break;
		default:
			return 1;
		}
	}
	return 0;
}

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

	if (ref->status != REF_STATUS_OK && ref->status != REF_STATUS_UPTODATE)
		return;

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

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

#define SUMMARY_WIDTH (2 * DEFAULT_ABBREV + 3)

static void print_ref_status(char flag, const char *summary, struct ref *to, struct ref *from, const char *msg)
{
	fprintf(stderr, " %c %-*s ", flag, SUMMARY_WIDTH, summary);
	if (from)
		fprintf(stderr, "%s -> %s", prettify_ref(from), prettify_ref(to));
	else
		fputs(prettify_ref(to), stderr);
	if (msg) {
		fputs(" (", stderr);
		fputs(msg, stderr);
		fputc(')', stderr);
	}
	fputc('\n', stderr);
}

static const char *status_abbrev(unsigned char sha1[20])
{
	return find_unique_abbrev(sha1, DEFAULT_ABBREV);
}

static void print_ok_ref_status(struct ref *ref)
{
	if (ref->deletion)
		print_ref_status('-', "[deleted]", ref, NULL, NULL);
	else if (is_null_sha1(ref->old_sha1))
		print_ref_status('*',
			(!prefixcmp(ref->name, "refs/tags/") ? "[new tag]" :
			  "[new branch]"),
			ref, ref->peer_ref, NULL);
	else {
		char quickref[84];
		char type;
		const char *msg;

		strcpy(quickref, status_abbrev(ref->old_sha1));
		if (ref->nonfastforward) {
			strcat(quickref, "...");
			type = '+';
			msg = "forced update";
		} else {
			strcat(quickref, "..");
			type = ' ';
			msg = NULL;
		}
		strcat(quickref, status_abbrev(ref->new_sha1));

		print_ref_status(type, quickref, ref, ref->peer_ref, msg);
	}
}

static int print_one_push_status(struct ref *ref, const char *dest, int count)
{
	if (!count)
		fprintf(stderr, "To %s\n", dest);

	switch(ref->status) {
	case REF_STATUS_NONE:
		print_ref_status('X', "[no match]", ref, NULL, NULL);
		break;
	case REF_STATUS_REJECT_NODELETE:
		print_ref_status('!', "[rejected]", ref, NULL,
				"remote does not support deleting refs");
		break;
	case REF_STATUS_UPTODATE:
		print_ref_status('=', "[up to date]", ref,
				ref->peer_ref, NULL);
		break;
	case REF_STATUS_REJECT_NONFASTFORWARD:
		print_ref_status('!', "[rejected]", ref, ref->peer_ref,
				"non-fast forward");
		break;
	case REF_STATUS_REMOTE_REJECT:
		print_ref_status('!', "[remote rejected]", ref,
				ref->deletion ? NULL : ref->peer_ref,
				ref->remote_status);
		break;
	case REF_STATUS_EXPECTING_REPORT:
		print_ref_status('!', "[remote failure]", ref,
				ref->deletion ? NULL : ref->peer_ref,
				"remote failed to report status");
		break;
	case REF_STATUS_OK:
		print_ok_ref_status(ref);
		break;
	}

	return 1;
}

static void print_push_status(const char *dest, struct ref *refs, int verbose)
{
	struct ref *ref;
	int n = 0;

	if (verbose) {
		for (ref = refs; ref; ref = ref->next)
			if (ref->status == REF_STATUS_UPTODATE)
				n += print_one_push_status(ref, dest, n);
	}

	for (ref = refs; ref; ref = ref->next)
		if (ref->status == REF_STATUS_OK)
			n += print_one_push_status(ref, dest, n);

	for (ref = refs; ref; ref = ref->next) {
		if (ref->status != REF_STATUS_NONE &&
		    ref->status != REF_STATUS_UPTODATE &&
		    ref->status != REF_STATUS_OK)
			n += print_one_push_status(ref, dest, n);
	}
}

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

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

		if (*local == '+')
			local++;

		/* A matching refspec is okay.  */
		if (remote == local && remote[1] == '\0')
			continue;

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

static int git_transport_push(struct transport *transport, struct ref *remote_refs, int flags)
{
	struct git_transport_data *data = transport->data;
	struct send_pack_args args;
	int ret;

	if (!data->conn) {
		struct ref *tmp_refs;
		connect_setup(transport, 1, 0);

		get_remote_heads(data->fd[0], &tmp_refs, 0, NULL, REF_NORMAL,
				 NULL);
	}

	args.send_mirror = !!(flags & TRANSPORT_PUSH_MIRROR);
	args.force_update = !!(flags & TRANSPORT_PUSH_FORCE);
	args.use_thin_pack = data->thin;
	args.verbose = !!(flags & TRANSPORT_PUSH_VERBOSE);
	args.dry_run = !!(flags & TRANSPORT_PUSH_DRY_RUN);

	ret = send_pack(&args, data->fd, data->conn, remote_refs,
			&data->extra_have);

	close(data->fd[1]);
	close(data->fd[0]);
	ret |= finish_connect(data->conn);
	data->conn = NULL;

	return ret;
}

static int disconnect_git(struct transport *transport)
{
	struct git_transport_data *data = transport->data;
	if (data->conn) {
		packet_flush(data->fd[1]);
		close(data->fd[0]);
		close(data->fd[1]);
		finish_connect(data->conn);
	}

	free(data);
	return 0;
}

static int is_local(const char *url)
{
	const char *colon = strchr(url, ':');
	const char *slash = strchr(url, '/');
	return !colon || (slash && slash < colon) ||
		has_dos_drive_prefix(url);
}

static int is_file(const char *url)
{
	struct stat buf;
	if (stat(url, &buf))
		return 0;
	return S_ISREG(buf.st_mode);
}

struct transport *transport_get(struct remote *remote, const char *url)
{
	struct transport *ret = xcalloc(1, sizeof(*ret));

	ret->remote = remote;
	ret->url = url;

	if (!prefixcmp(url, "rsync:")) {
		ret->get_refs_list = get_refs_via_rsync;
		ret->fetch = fetch_objs_via_rsync;
		ret->push = rsync_transport_push;

	} else if (!prefixcmp(url, "http://")
	        || !prefixcmp(url, "https://")
	        || !prefixcmp(url, "ftp://")) {
#ifdef NO_CURL
		error("git was compiled without libcurl support.");
#else
		ret->get_refs_list = get_refs_via_curl;
		ret->fetch = fetch_objs_via_curl;
		ret->push = curl_transport_push;
#endif
		ret->disconnect = disconnect_walker;

	} else if (is_local(url) && is_file(url)) {
		struct bundle_transport_data *data = xcalloc(1, sizeof(*data));
		ret->data = data;
		ret->get_refs_list = get_refs_from_bundle;
		ret->fetch = fetch_refs_from_bundle;
		ret->disconnect = close_bundle;

	} else {
		struct git_transport_data *data = xcalloc(1, sizeof(*data));
		ret->data = data;
		ret->set_option = set_git_option;
		ret->get_refs_list = get_refs_via_connect;
		ret->fetch = fetch_refs_via_pack;
		ret->push_refs = git_transport_push;
		ret->disconnect = disconnect_git;

		data->thin = 1;
		data->conn = NULL;
		data->uploadpack = "git-upload-pack";
		if (remote && remote->uploadpack)
			data->uploadpack = remote->uploadpack;
		data->receivepack = "git-receive-pack";
		if (remote && remote->receivepack)
			data->receivepack = remote->receivepack;
	}

	return ret;
}

int transport_set_option(struct transport *transport,
			 const char *name, const char *value)
{
	if (transport->set_option)
		return transport->set_option(transport, name, value);
	return 1;
}

int transport_push(struct transport *transport,
		   int refspec_nr, const char **refspec, int flags)
{
	verify_remote_names(refspec_nr, refspec);

	if (transport->push)
		return transport->push(transport, refspec_nr, refspec, flags);
	if (transport->push_refs) {
		struct ref *remote_refs =
			transport->get_refs_list(transport, 1);
		struct ref **remote_tail;
		struct ref *local_refs = get_local_heads();
		int match_flags = MATCH_REFS_NONE;
		int verbose = flags & TRANSPORT_PUSH_VERBOSE;
		int ret;

		if (flags & TRANSPORT_PUSH_ALL)
			match_flags |= MATCH_REFS_ALL;
		if (flags & TRANSPORT_PUSH_MIRROR)
			match_flags |= MATCH_REFS_MIRROR;

		remote_tail = &remote_refs;
		while (*remote_tail)
			remote_tail = &((*remote_tail)->next);
		if (match_refs(local_refs, remote_refs, &remote_tail,
			       refspec_nr, refspec, match_flags)) {
			return -1;
		}

		ret = transport->push_refs(transport, remote_refs, flags);

		print_push_status(transport->url, remote_refs, verbose);

		if (!(flags & TRANSPORT_PUSH_DRY_RUN)) {
			struct ref *ref;
			for (ref = remote_refs; ref; ref = ref->next)
				update_tracking_ref(transport->remote, ref, verbose);
		}

		if (!ret && !refs_pushed(remote_refs))
			fprintf(stderr, "Everything up-to-date\n");
		return ret;
	}
	return 1;
}

const struct ref *transport_get_remote_refs(struct transport *transport)
{
	if (!transport->remote_refs)
		transport->remote_refs = transport->get_refs_list(transport, 0);
	return transport->remote_refs;
}

int transport_fetch_refs(struct transport *transport, const struct ref *refs)
{
	int rc;
	int nr_heads = 0, nr_alloc = 0, nr_refs = 0;
	const struct ref **heads = NULL;
	const struct ref *rm;

	for (rm = refs; rm; rm = rm->next) {
		nr_refs++;
		if (rm->peer_ref &&
		    !hashcmp(rm->peer_ref->old_sha1, rm->old_sha1))
			continue;
		ALLOC_GROW(heads, nr_heads + 1, nr_alloc);
		heads[nr_heads++] = rm;
	}

	if (!nr_heads) {
		/*
		 * When deepening of a shallow repository is requested,
		 * then local and remote refs are likely to still be equal.
		 * Just feed them all to the fetch method in that case.
		 * This condition shouldn't be met in a non-deepening fetch
		 * (see builtin-fetch.c:quickfetch()).
		 */
		heads = xmalloc(nr_refs * sizeof(*heads));
		for (rm = refs; rm; rm = rm->next)
			heads[nr_heads++] = rm;
	}

	rc = transport->fetch(transport, nr_heads, heads);
	free(heads);
	return rc;
}

void transport_unlock_pack(struct transport *transport)
{
	if (transport->pack_lockfile) {
		unlink_or_warn(transport->pack_lockfile);
		free(transport->pack_lockfile);
		transport->pack_lockfile = NULL;
	}
}

int transport_disconnect(struct transport *transport)
{
	int ret = 0;
	if (transport->disconnect)
		ret = transport->disconnect(transport);
	free(transport);
	return ret;
}