[PATCHv4 3/4] Support ref namespaces for remote repositories via upload-pack and receive-pack

[Jamey Sharp <jamey@minilop.net>]

From: Josh Triplett <josh@joshtriplett.org>

Change upload-pack and receive-pack to use the namespace-prefixed refs
when working with the repository, and use the unprefixed refs when
talking to the client, maintaining the masquerade.  This allows
clone, pull, fetch, and push to work with a suitably configured
GIT_NAMESPACE.

With appropriate configuration, this also allows http-backend to expose
namespaces as multiple repositories with different paths.  This only
requires setting GIT_NAMESPACE, which http-backend passes through to
upload-pack and receive-pack.

Commit by Josh Triplett and Jamey Sharp.

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Jamey Sharp <jamey@minilop.net>
---
This patch is not that different from v3, but now uses general
infrastructure from refs.c introduced in patch 2/4.

 builtin/receive-pack.c |   32 +++++++++++++++++++++++++-------
 upload-pack.c          |   15 ++++++++-------
 2 files changed, 33 insertions(+), 14 deletions(-)

diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index e1a687a..9bb268a 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -109,6 +109,7 @@ static int receive_pack_config(const char *var, const char *value, void *cb)
 
 static int show_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 {
+	path = path ? strip_namespace(path) : "capabilities^{}";
 	if (sent_capabilities)
 		packet_write(1, "%s %s\n", sha1_to_hex(sha1), path);
 	else
@@ -122,9 +123,9 @@ static int show_ref(const char *path, const unsigned char *sha1, int flag, void
 
 static void write_head_info(void)
 {
-	for_each_ref(show_ref, NULL);
+	for_each_namespaced_ref(show_ref, NULL);
 	if (!sent_capabilities)
-		show_ref("capabilities^{}", null_sha1, 0, NULL);
+		show_ref(NULL, null_sha1, 0, NULL);
 
 }
 
@@ -333,6 +334,8 @@ static void refuse_unconfigured_deny_delete_current(void)
 static const char *update(struct command *cmd)
 {
 	const char *name = cmd->ref_name;
+	struct strbuf namespaced_name_buf = STRBUF_INIT;
+	const char *namespaced_name;
 	unsigned char *old_sha1 = cmd->old_sha1;
 	unsigned char *new_sha1 = cmd->new_sha1;
 	struct ref_lock *lock;
@@ -343,7 +346,10 @@ static const char *update(struct command *cmd)
 		return "funny refname";
 	}
 
-	if (is_ref_checked_out(name)) {
+	strbuf_addf(&namespaced_name_buf, "%s%s", get_git_namespace(), name);
+	namespaced_name = strbuf_detach(&namespaced_name_buf, NULL);
+
+	if (is_ref_checked_out(namespaced_name)) {
 		switch (deny_current_branch) {
 		case DENY_IGNORE:
 			break;
@@ -371,7 +377,7 @@ static const char *update(struct command *cmd)
 			return "deletion prohibited";
 		}
 
-		if (!strcmp(name, head_name)) {
+		if (!strcmp(namespaced_name, head_name)) {
 			switch (deny_delete_current) {
 			case DENY_IGNORE:
 				break;
@@ -427,14 +433,14 @@ static const char *update(struct command *cmd)
 			rp_warning("Allowing deletion of corrupt ref.");
 			old_sha1 = NULL;
 		}
-		if (delete_ref(name, old_sha1, 0)) {
+		if (delete_ref(namespaced_name, old_sha1, 0)) {
 			rp_error("failed to delete %s", name);
 			return "failed to delete";
 		}
 		return NULL; /* good */
 	}
 	else {
-		lock = lock_any_ref_for_update(name, old_sha1, 0);
+		lock = lock_any_ref_for_update(namespaced_name, old_sha1, 0);
 		if (!lock) {
 			rp_error("failed to lock %s", name);
 			return "failed to lock";
@@ -491,17 +497,29 @@ static void run_update_post_hook(struct command *commands)
 
 static void check_aliased_update(struct command *cmd, struct string_list *list)
 {
+	struct strbuf buf = STRBUF_INIT;
+	const char *dst_name;
 	struct string_list_item *item;
 	struct command *dst_cmd;
 	unsigned char sha1[20];
 	char cmd_oldh[41], cmd_newh[41], dst_oldh[41], dst_newh[41];
 	int flag;
 
-	const char *dst_name = resolve_ref(cmd->ref_name, sha1, 0, &flag);
+	strbuf_addf(&buf, "%s%s", get_git_namespace(), cmd->ref_name);
+	dst_name = resolve_ref(buf.buf, sha1, 0, &flag);
+	strbuf_release(&buf);
 
 	if (!(flag & REF_ISSYMREF))
 		return;
 
+	dst_name = strip_namespace(dst_name);
+	if (!dst_name) {
+		rp_error("refusing update to broken symref '%s'", cmd->ref_name);
+		cmd->skip_update = 1;
+		cmd->error_string = "broken symref";
+		return;
+	}
+
 	if ((item = string_list_lookup(list, dst_name)) == NULL)
 		return;
 
diff --git a/upload-pack.c b/upload-pack.c
index ce5cbbe..267e5b1 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -641,16 +641,17 @@ static int send_ref(const char *refname, const unsigned char *sha1, int flag, vo
 		" side-band-64k ofs-delta shallow no-progress"
 		" include-tag multi_ack_detailed";
 	struct object *o = parse_object(sha1);
+	const char *refname_nons = strip_namespace(refname);
 
 	if (!o)
 		die("git upload-pack: cannot find object %s:", sha1_to_hex(sha1));
 
 	if (capabilities)
-		packet_write(1, "%s %s%c%s%s\n", sha1_to_hex(sha1), refname,
+		packet_write(1, "%s %s%c%s%s\n", sha1_to_hex(sha1), refname_nons,
 			     0, capabilities,
 			     stateless_rpc ? " no-done" : "");
 	else
-		packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname);
+		packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname_nons);
 	capabilities = NULL;
 	if (!(o->flags & OUR_REF)) {
 		o->flags |= OUR_REF;
@@ -659,7 +660,7 @@ static int send_ref(const char *refname, const unsigned char *sha1, int flag, vo
 	if (o->type == OBJ_TAG) {
 		o = deref_tag(o, refname, 0);
 		if (o)
-			packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname);
+			packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname_nons);
 	}
 	return 0;
 }
@@ -680,12 +681,12 @@ static void upload_pack(void)
 {
 	if (advertise_refs || !stateless_rpc) {
 		reset_timeout();
-		head_ref(send_ref, NULL);
-		for_each_ref(send_ref, NULL);
+		head_ref_namespaced(send_ref, NULL);
+		for_each_namespaced_ref(send_ref, NULL);
 		packet_flush(1);
 	} else {
-		head_ref(mark_our_ref, NULL);
-		for_each_ref(mark_our_ref, NULL);
+		head_ref_namespaced(mark_our_ref, NULL);
+		for_each_namespaced_ref(mark_our_ref, NULL);
 	}
 	if (advertise_refs)
 		return;
-- 
1.7.5.3