connect: in ref advertisement, shallows are last
Currently, get_remote_heads() parses the ref advertisement in one loop, allowing refs and shallow lines to intersperse, despite this not being allowed by the specification. Refactor get_remote_heads() to use two loops instead, enforcing that refs come first, and then shallows. This also makes it easier to teach get_remote_heads() to interpret other lines in the ref advertisement, which will be done in a subsequent patch. As part of this change, this patch interprets capabilities only on the first line in the ref advertisement, printing a warning message when encountering capabilities on other lines. Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Brandon Williams <bmwill@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>maint
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							|  | @ -11,6 +11,7 @@ | |||
| #include "string-list.h" | ||||
| #include "sha1-array.h" | ||||
| #include "transport.h" | ||||
| #include "strbuf.h" | ||||
|  | ||||
| static char *server_capabilities; | ||||
| static const char *parse_feature_value(const char *, const char *, int *); | ||||
|  | @ -107,6 +108,104 @@ static void annotate_refs_with_symref_info(struct ref *ref) | |||
| 	string_list_clear(&symref, 0); | ||||
| } | ||||
|  | ||||
| /* | ||||
|  * Read one line of a server's ref advertisement into packet_buffer. | ||||
|  */ | ||||
| static int read_remote_ref(int in, char **src_buf, size_t *src_len, | ||||
| 			   int *responded) | ||||
| { | ||||
| 	int len = packet_read(in, src_buf, src_len, | ||||
| 			      packet_buffer, sizeof(packet_buffer), | ||||
| 			      PACKET_READ_GENTLE_ON_EOF | | ||||
| 			      PACKET_READ_CHOMP_NEWLINE); | ||||
| 	const char *arg; | ||||
| 	if (len < 0) | ||||
| 		die_initial_contact(*responded); | ||||
| 	if (len > 4 && skip_prefix(packet_buffer, "ERR ", &arg)) | ||||
| 		die("remote error: %s", arg); | ||||
|  | ||||
| 	*responded = 1; | ||||
|  | ||||
| 	return len; | ||||
| } | ||||
|  | ||||
| #define EXPECTING_FIRST_REF 0 | ||||
| #define EXPECTING_REF 1 | ||||
| #define EXPECTING_SHALLOW 2 | ||||
|  | ||||
| static void process_capabilities(int *len) | ||||
| { | ||||
| 	int nul_location = strlen(packet_buffer); | ||||
| 	if (nul_location == *len) | ||||
| 		return; | ||||
| 	server_capabilities = xstrdup(packet_buffer + nul_location + 1); | ||||
| 	*len = nul_location; | ||||
| } | ||||
|  | ||||
| static int process_dummy_ref(void) | ||||
| { | ||||
| 	struct object_id oid; | ||||
| 	const char *name; | ||||
|  | ||||
| 	if (parse_oid_hex(packet_buffer, &oid, &name)) | ||||
| 		return 0; | ||||
| 	if (*name != ' ') | ||||
| 		return 0; | ||||
| 	name++; | ||||
|  | ||||
| 	return !oidcmp(&null_oid, &oid) && !strcmp(name, "capabilities^{}"); | ||||
| } | ||||
|  | ||||
| static void check_no_capabilities(int len) | ||||
| { | ||||
| 	if (strlen(packet_buffer) != len) | ||||
| 		warning("Ignoring capabilities after first line '%s'", | ||||
| 			packet_buffer + strlen(packet_buffer)); | ||||
| } | ||||
|  | ||||
| static int process_ref(int len, struct ref ***list, unsigned int flags, | ||||
| 		       struct oid_array *extra_have) | ||||
| { | ||||
| 	struct object_id old_oid; | ||||
| 	const char *name; | ||||
|  | ||||
| 	if (parse_oid_hex(packet_buffer, &old_oid, &name)) | ||||
| 		return 0; | ||||
| 	if (*name != ' ') | ||||
| 		return 0; | ||||
| 	name++; | ||||
|  | ||||
| 	if (extra_have && !strcmp(name, ".have")) { | ||||
| 		oid_array_append(extra_have, &old_oid); | ||||
| 	} else if (!strcmp(name, "capabilities^{}")) { | ||||
| 		die("protocol error: unexpected capabilities^{}"); | ||||
| 	} else if (check_ref(name, flags)) { | ||||
| 		struct ref *ref = alloc_ref(name); | ||||
| 		oidcpy(&ref->old_oid, &old_oid); | ||||
| 		**list = ref; | ||||
| 		*list = &ref->next; | ||||
| 	} | ||||
| 	check_no_capabilities(len); | ||||
| 	return 1; | ||||
| } | ||||
|  | ||||
| static int process_shallow(int len, struct oid_array *shallow_points) | ||||
| { | ||||
| 	const char *arg; | ||||
| 	struct object_id old_oid; | ||||
|  | ||||
| 	if (!skip_prefix(packet_buffer, "shallow ", &arg)) | ||||
| 		return 0; | ||||
|  | ||||
| 	if (get_oid_hex(arg, &old_oid)) | ||||
| 		die("protocol error: expected shallow sha-1, got '%s'", arg); | ||||
| 	if (!shallow_points) | ||||
| 		die("repository on the other end cannot be shallow"); | ||||
| 	oid_array_append(shallow_points, &old_oid); | ||||
| 	check_no_capabilities(len); | ||||
| 	return 1; | ||||
| } | ||||
|  | ||||
| /* | ||||
|  * Read all the refs from the other end | ||||
|  */ | ||||
|  | @ -123,76 +222,34 @@ struct ref **get_remote_heads(int in, char *src_buf, size_t src_len, | |||
| 	 * willing to talk to us.  A hang-up before seeing any | ||||
| 	 * response does not necessarily mean an ACL problem, though. | ||||
| 	 */ | ||||
| 	int saw_response; | ||||
| 	int got_dummy_ref_with_capabilities_declaration = 0; | ||||
| 	int responded = 0; | ||||
| 	int len; | ||||
| 	int state = EXPECTING_FIRST_REF; | ||||
|  | ||||
| 	*list = NULL; | ||||
| 	for (saw_response = 0; ; saw_response = 1) { | ||||
| 		struct ref *ref; | ||||
| 		struct object_id old_oid; | ||||
| 		char *name; | ||||
| 		int len, name_len; | ||||
| 		char *buffer = packet_buffer; | ||||
| 		const char *arg; | ||||
|  | ||||
| 		len = packet_read(in, &src_buf, &src_len, | ||||
| 				  packet_buffer, sizeof(packet_buffer), | ||||
| 				  PACKET_READ_GENTLE_ON_EOF | | ||||
| 				  PACKET_READ_CHOMP_NEWLINE); | ||||
| 		if (len < 0) | ||||
| 			die_initial_contact(saw_response); | ||||
|  | ||||
| 		if (!len) | ||||
| 			break; | ||||
|  | ||||
| 		if (len > 4 && skip_prefix(buffer, "ERR ", &arg)) | ||||
| 			die("remote error: %s", arg); | ||||
|  | ||||
| 		if (len == GIT_SHA1_HEXSZ + strlen("shallow ") && | ||||
| 			skip_prefix(buffer, "shallow ", &arg)) { | ||||
| 			if (get_oid_hex(arg, &old_oid)) | ||||
| 				die("protocol error: expected shallow sha-1, got '%s'", arg); | ||||
| 			if (!shallow_points) | ||||
| 				die("repository on the other end cannot be shallow"); | ||||
| 			oid_array_append(shallow_points, &old_oid); | ||||
| 			continue; | ||||
| 	while ((len = read_remote_ref(in, &src_buf, &src_len, &responded))) { | ||||
| 		switch (state) { | ||||
| 		case EXPECTING_FIRST_REF: | ||||
| 			process_capabilities(&len); | ||||
| 			if (process_dummy_ref()) { | ||||
| 				state = EXPECTING_SHALLOW; | ||||
| 				break; | ||||
| 			} | ||||
| 			state = EXPECTING_REF; | ||||
| 			/* fallthrough */ | ||||
| 		case EXPECTING_REF: | ||||
| 			if (process_ref(len, &list, flags, extra_have)) | ||||
| 				break; | ||||
| 			state = EXPECTING_SHALLOW; | ||||
| 			/* fallthrough */ | ||||
| 		case EXPECTING_SHALLOW: | ||||
| 			if (process_shallow(len, shallow_points)) | ||||
| 				break; | ||||
| 			die("protocol error: unexpected '%s'", packet_buffer); | ||||
| 		default: | ||||
| 			die("unexpected state %d", state); | ||||
| 		} | ||||
|  | ||||
| 		if (len < GIT_SHA1_HEXSZ + 2 || get_oid_hex(buffer, &old_oid) || | ||||
| 			buffer[GIT_SHA1_HEXSZ] != ' ') | ||||
| 			die("protocol error: expected sha/ref, got '%s'", buffer); | ||||
| 		name = buffer + GIT_SHA1_HEXSZ + 1; | ||||
|  | ||||
| 		name_len = strlen(name); | ||||
| 		if (len != name_len + GIT_SHA1_HEXSZ + 1) { | ||||
| 			free(server_capabilities); | ||||
| 			server_capabilities = xstrdup(name + name_len + 1); | ||||
| 		} | ||||
|  | ||||
| 		if (extra_have && !strcmp(name, ".have")) { | ||||
| 			oid_array_append(extra_have, &old_oid); | ||||
| 			continue; | ||||
| 		} | ||||
|  | ||||
| 		if (!strcmp(name, "capabilities^{}")) { | ||||
| 			if (saw_response) | ||||
| 				die("protocol error: unexpected capabilities^{}"); | ||||
| 			if (got_dummy_ref_with_capabilities_declaration) | ||||
| 				die("protocol error: multiple capabilities^{}"); | ||||
| 			got_dummy_ref_with_capabilities_declaration = 1; | ||||
| 			continue; | ||||
| 		} | ||||
|  | ||||
| 		if (!check_ref(name, flags)) | ||||
| 			continue; | ||||
|  | ||||
| 		if (got_dummy_ref_with_capabilities_declaration) | ||||
| 			die("protocol error: unexpected ref after capabilities^{}"); | ||||
|  | ||||
| 		ref = alloc_ref(buffer + GIT_SHA1_HEXSZ + 1); | ||||
| 		oidcpy(&ref->old_oid, &old_oid); | ||||
| 		*list = ref; | ||||
| 		list = &ref->next; | ||||
| 	} | ||||
|  | ||||
| 	annotate_refs_with_symref_info(*orig_list); | ||||
|  |  | |||
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	 Jonathan Tan
						Jonathan Tan