Renaming push.

This allows git-send-pack to push local refs to a destination
repository under different names.

Here is the name mapping rules for refs.

* If there is no ref mapping on the command line:

 - if '--all' is specified, it is equivalent to specifying
   <local> ":" <local> for all the existing local refs on the
   command line
 - otherwise, it is equivalent to specifying <ref> ":" <ref> for
   all the refs that exist on both sides.

* <name> is just a shorthand for <name> ":" <name>

* <src> ":" <dst>

  push ref that matches <src> to ref that matches <dst>.

  - It is an error if <src> does not match exactly one of local
    refs.

  - It is an error if <dst> matches more than one remote refs.

  - If <dst> does not match any remote refs, either

    - it has to start with "refs/"; <dst> is used as the
      destination literally in this case.

    - <src> == <dst> and the ref that matched the <src> must not
      exist in the set of remote refs; the ref matched <src>
      locally is used as the name of the destination.

For example,

  - "git-send-pack --all <remote>" works exactly as before;

  - "git-send-pack <remote> master:upstream" pushes local master
    to remote ref that matches "upstream".  If there is no such
    ref, it is an error.

  - "git-send-pack <remote> master:refs/heads/upstream" pushes
    local master to remote refs/heads/upstream, even when
    refs/heads/upstream does not exist.

  - "git-send-pack <remote> master" into an empty remote
    repository pushes the local ref/heads/master to the remote
    ref/heads/master.

Signed-off-by: Junio C Hamano <junkio@cox.net>

cache.h

@@ -302,12 +302,15 @@ struct ref {
 	struct ref *next;
 	unsigned char old_sha1[20];
 	unsigned char new_sha1[20];
+	struct ref *peer_ref; /* when renaming */
 	char name[0];
 };
 
 extern int git_connect(int fd[2], char *url, const char *prog);
 extern int finish_connect(pid_t pid);
 extern int path_match(const char *path, int nr, char **match);
+extern int match_refs(struct ref *src, struct ref *dst, struct ref ***dst_tail,
+		      int nr_refspec, char **refspec, int all);
 extern int get_ack(int fd, unsigned char *result_sha1);
 extern struct ref **get_remote_heads(int in, struct ref **list, int nr_match, char **match);
 

connect.c

@@ -31,11 +31,9 @@ struct ref **get_remote_heads(int in, struct ref **list, int nr_match, char **ma
 		name = buffer + 41;
 		if (nr_match && !path_match(name, nr_match, match))
 			continue;
-		ref = xmalloc(sizeof(*ref) + len - 40);
+		ref = xcalloc(1, sizeof(*ref) + len - 40);
 		memcpy(ref->old_sha1, old_sha1, 20);
-		memset(ref->new_sha1, 0, 20);
 		memcpy(ref->name, buffer + 41, len - 40);
-		ref->next = NULL;
 		*list = ref;
 		list = &ref->next;
 	}
@@ -81,6 +79,174 @@ int path_match(const char *path, int nr, char **match)
 	return 0;
 }
 
+struct refspec {
+	char *src;
+	char *dst;
+};
+
+static struct refspec *parse_ref_spec(int nr_refspec, char **refspec)
+{
+	int i;
+	struct refspec *rs = xmalloc(sizeof(*rs) * (nr_refspec + 1));
+	for (i = 0; i < nr_refspec; i++) {
+		char *sp, *dp, *ep;
+		sp = refspec[i];
+		ep = strchr(sp, ':');
+		if (ep) {
+			dp = ep + 1;
+			*ep = 0;
+		}
+		else
+			dp = sp;
+		rs[i].src = sp;
+		rs[i].dst = dp;
+	}
+	rs[nr_refspec].src = rs[nr_refspec].dst = NULL;
+	return rs;
+}
+
+static int count_refspec_match(const char *pattern,
+			       struct ref *refs,
+			       struct ref **matched_ref)
+{
+	int match;
+	int patlen = strlen(pattern);
+
+	for (match = 0; refs; refs = refs->next) {
+		char *name = refs->name;
+		int namelen = strlen(name);
+		if (namelen < patlen ||
+		    memcmp(name + namelen - patlen, pattern, patlen))
+			continue;
+		if (namelen != patlen && name[namelen - patlen - 1] != '/')
+			continue;
+		match++;
+		*matched_ref = refs;
+	}
+	return match;
+}
+
+static void link_dst_tail(struct ref *ref, struct ref ***tail)
+{
+	**tail = ref;
+	*tail = &ref->next;
+	**tail = NULL;
+}
+
+static int match_explicit_refs(struct ref *src, struct ref *dst,
+			       struct ref ***dst_tail, struct refspec *rs)
+{
+	int i, errs;
+	for (i = errs = 0; rs[i].src; i++) {
+		struct ref *matched_src, *matched_dst;
+
+		matched_src = matched_dst = NULL;
+		switch (count_refspec_match(rs[i].src, src, &matched_src)) {
+		case 1:
+			break;
+		case 0:
+			errs = 1;
+			error("src refspec %s does not match any.");
+			break;
+		default:
+			errs = 1;
+			error("src refspec %s matches more than one.",
+			      rs[i].src);
+			break;
+		}
+		switch (count_refspec_match(rs[i].dst, dst, &matched_dst)) {
+		case 1:
+			break;
+		case 0:
+			if (!memcmp(rs[i].dst, "refs/", 5)) {
+				int len = strlen(rs[i].dst) + 1;
+				matched_dst = xcalloc(1, sizeof(*dst) + len);
+				memcpy(matched_dst->name, rs[i].dst, len);
+				link_dst_tail(matched_dst, dst_tail);
+			}
+			else if (!strcmp(rs[i].src, rs[i].dst) &&
+				 matched_src) {
+				/* pushing "master:master" when
+				 * remote does not have master yet.
+				 */
+				int len = strlen(matched_src->name);
+				matched_dst = xcalloc(1, sizeof(*dst) + len);
+				memcpy(matched_dst->name, matched_src->name,
+				       len);
+				link_dst_tail(matched_dst, dst_tail);
+			}
+			else {
+				errs = 1;
+				error("dst refspec %s does not match any "
+				      "existing ref on the remote and does "
+				      "not start with refs/.", rs[i].dst);
+			}
+			break;
+		default:
+			errs = 1;
+			error("dst refspec %s matches more than one.",
+			      rs[i].dst);
+			break;
+		}
+		if (errs)
+			continue;
+		if (matched_src->peer_ref) {
+			errs = 1;
+			error("src ref %s is sent to more than one dst.",
+			      matched_src->name);
+		}
+		else
+			matched_src->peer_ref = matched_dst;
+		if (matched_dst->peer_ref) {
+			errs = 1;
+			error("dst ref %s receives from more than one src.",
+			      matched_dst->name);
+		}
+		else
+			matched_dst->peer_ref = matched_src;
+	}
+	return -errs;
+}
+
+static struct ref *find_ref_by_name(struct ref *list, const char *name)
+{
+	for ( ; list; list = list->next)
+		if (!strcmp(list->name, name))
+			return list;
+	return NULL;
+}
+
+int match_refs(struct ref *src, struct ref *dst, struct ref ***dst_tail,
+	       int nr_refspec, char **refspec, int all)
+{
+	struct refspec *rs = parse_ref_spec(nr_refspec, refspec);
+
+	if (nr_refspec)
+		return match_explicit_refs(src, dst, dst_tail, rs);
+
+	/* pick the remainder */
+	for ( ; src; src = src->next) {
+		struct ref *dst_peer;
+		if (src->peer_ref)
+			continue;
+		dst_peer = find_ref_by_name(dst, src->name);
+		if (dst_peer && dst_peer->peer_ref)
+			continue;
+		if (!dst_peer) {
+			if (!all)
+				continue;
+			/* Create a new one and link it */
+			int len = strlen(src->name) + 1;
+			dst_peer = xcalloc(1, sizeof(*dst_peer) + len);
+			memcpy(dst_peer->name, src->name, len);
+			memcpy(dst_peer->new_sha1, src->new_sha1, 20);
+			link_dst_tail(dst_peer, dst_tail);
+		}
+		dst_peer->peer_ref = src;
+	}
+	return 0;
+}
+
 enum protocol {
 	PROTO_LOCAL = 1,
 	PROTO_SSH,

send-pack.c

@@ -104,21 +104,6 @@ static int pack_objects(int fd, struct ref *refs)
 	return 0;
 }
 
-static int read_ref(const char *ref, unsigned char *sha1)
-{
-	int fd, ret;
-	char buffer[60];
-
-	fd = open(git_path("%s", ref), O_RDONLY);
-	if (fd < 0)
-		return -1;
-	ret = -1;
-	if (read(fd, buffer, sizeof(buffer)) >= 40)
-		ret = get_sha1_hex(buffer, sha1);
-	close(fd);
-	return ret;
-}
-
 static int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
 {
 	struct commit *new, *old;
@@ -144,114 +129,92 @@ static int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha
 	return 0;
 }
 
-static int local_ref_nr_match;
+static struct ref *local_refs, **local_tail;
-static char **local_ref_match;
+static struct ref *remote_refs, **remote_tail;
-static struct ref *local_ref_list;
-static struct ref **local_last_ref;
 
-static int try_to_match(const char *refname, const unsigned char *sha1)
+static int one_local_ref(const char *refname, const unsigned char *sha1)
 {
 	struct ref *ref;
-	int len;
+	int len = strlen(refname) + 1;
-
+	ref = xcalloc(1, sizeof(*ref) + len);
-	if (!path_match(refname, local_ref_nr_match, local_ref_match)) {
-		if (!send_all)
-			return 0;
-
-		/* If we have it listed already, skip it */
-		for (ref = local_ref_list ; ref ; ref = ref->next) {
-			if (!strcmp(ref->name, refname))
-				return 0;
-		}
-	}
-
-	len = strlen(refname)+1;
-	ref = xmalloc(sizeof(*ref) + len);
-	memset(ref->old_sha1, 0, 20);
 	memcpy(ref->new_sha1, sha1, 20);
 	memcpy(ref->name, refname, len);
-	ref->next = NULL;
+	*local_tail = ref;
-	*local_last_ref = ref;
+	local_tail = &ref->next;
-	local_last_ref = &ref->next;
 	return 0;
 }
 
-static int send_pack(int in, int out, int nr_match, char **match)
+static void get_local_heads(void)
+{
+	local_tail = &local_refs;
+	for_each_ref(one_local_ref);
+}
+
+static int send_pack(int in, int out, int nr_refspec, char **refspec)
 {
-	struct ref *ref_list, **last_ref;
 	struct ref *ref;
 	int new_refs;
 
-	/* First we get all heads, whether matching or not.. */
+	/* No funny business with the matcher */
-	last_ref = get_remote_heads(in, &ref_list, 0, NULL);
+	remote_tail = get_remote_heads(in, &remote_refs, 0, NULL);
-
+	get_local_heads();
-	/*
-	 * Go through the refs, see if we want to update
-	 * any of them..
-	 */
-	for (ref = ref_list; ref; ref = ref->next) {
-		unsigned char new_sha1[20];
-		char *name = ref->name;
-
-		if (nr_match && !path_match(name, nr_match, match))
-			continue;
-
-		if (read_ref(name, new_sha1) < 0)
-			continue;
-
-		if (!memcmp(ref->old_sha1, new_sha1, 20)) {
-			fprintf(stderr, "'%s' unchanged\n", name);
-			continue;
-		}
-
-		if (!has_sha1_file(ref->old_sha1)) {
-			error("remote '%s' object %s does not exist on local",
-			      name, sha1_to_hex(ref->old_sha1));
-			continue;
-		}
-
-		if (!ref_newer(new_sha1, ref->old_sha1)) {
-			error("remote '%s' isn't a strict parent of local", name);
-			continue;
-		}
-
-		/* Ok, mark it for update */
-		memcpy(ref->new_sha1, new_sha1, 20);
-	}
-
-	/*
-	 * See if we have any refs that the other end didn't have
-	 */
-	if (nr_match || send_all) {
-		local_ref_nr_match = nr_match;
-		local_ref_match = match;
-		local_ref_list = ref_list;
-		local_last_ref = last_ref;
-		for_each_ref(try_to_match);
-	}
 
+	/* match them up */
+	if (!remote_tail)
+		remote_tail = &remote_refs;
+	if (match_refs(local_refs, remote_refs, &remote_tail,
+		       nr_refspec, refspec, send_all))
+		return -1;
 	/*
 	 * Finally, tell the other end!
 	 */
 	new_refs = 0;
-	for (ref = ref_list; ref; ref = ref->next) {
+	for (ref = remote_refs; ref; ref = ref->next) {
 		char old_hex[60], *new_hex;
-		if (is_zero_sha1(ref->new_sha1))
+		if (!ref->peer_ref)
 			continue;
+		if (!is_zero_sha1(ref->old_sha1)) {
+			if (!has_sha1_file(ref->old_sha1)) {
+				error("remote '%s' object %s does not "
+				      "exist on local",
+				      ref->name, sha1_to_hex(ref->old_sha1));
+				continue;
+			}
+			if (!ref_newer(ref->peer_ref->new_sha1,
+				       ref->old_sha1)) {
+				error("remote ref '%s' is not a strict "
+				      "subset of local ref '%s'.", ref->name,
+				      ref->peer_ref->name);
+				continue;
+			}
+		}
+		if (!memcmp(ref->old_sha1, ref->peer_ref->new_sha1, 20)) {
+			fprintf(stderr, "'%s': up-to-date\n", ref->name);
+			continue;
+		}
+		memcpy(ref->new_sha1, ref->peer_ref->new_sha1, 20);
+		if (is_zero_sha1(ref->new_sha1)) {
+			error("cannot happen anymore");
+			continue;
+		}
 		new_refs++;
 		strcpy(old_hex, sha1_to_hex(ref->old_sha1));
 		new_hex = sha1_to_hex(ref->new_sha1);
 		packet_write(out, "%s %s %s", old_hex, new_hex, ref->name);
-		fprintf(stderr, "'%s': updating from %s to %s\n", ref->name, old_hex, new_hex);
+		fprintf(stderr, "updating '%s'", ref->name);
+		if (strcmp(ref->name, ref->peer_ref->name))
+			fprintf(stderr, " using '%s'", ref->peer_ref->name);
+		fprintf(stderr, "\n  from %s\n  to   %s\n", old_hex, new_hex);
 	}
-	
+
 	packet_flush(out);
 	if (new_refs)
-		pack_objects(out, ref_list);
+		pack_objects(out, remote_refs);
 	close(out);
 	return 0;
 }
 
+
 int main(int argc, char **argv)
 {
 	int i, nr_heads = 0;