git/protocol-caps.c

#include "git-compat-util.h"
#include "protocol-caps.h"
#include "gettext.h"
#include "hex.h"
#include "pkt-line.h"
#include "hash.h"
#include "object.h"
#include "odb.h"
#include "repository.h"
#include "string-list.h"
#include "strbuf.h"

struct requested_info {
	unsigned size : 1;
};

/*
 * Parses oids from the given line and collects them in the given
 * oid_str_list. Returns 1 if parsing was successful and 0 otherwise.
 */
static int parse_oid(const char *line, struct string_list *oid_str_list)
{
	const char *arg;

	if (!skip_prefix(line, "oid ", &arg))
		return 0;

	string_list_append(oid_str_list, arg);

	return 1;
}

/*
 * odb_read_object_info_extended() wrapper. Similar to odb_read_object_info()
 * but uses the flags:
 *
 * - OBJECT_INFO_SKIP_FETCH_OBJECT so a server won't fetch an object when a
 *   object-info request asks for an OID that it doesn't have.
 *
 * - OBJECT_INFO_QUICK to avoid re-scanning packs when the object is not found.
 */
static enum object_type get_object_info(struct object_database *odb,
			   const struct object_id *oid,
			   size_t *sizep)
{
	enum object_type type;
	struct object_info oi = OBJECT_INFO_INIT;

	oi.typep = &type;
	oi.sizep = sizep;
	if (odb_read_object_info_extended(odb, oid, &oi,
					  OBJECT_INFO_LOOKUP_REPLACE |
					  OBJECT_INFO_SKIP_FETCH_OBJECT |
					  OBJECT_INFO_QUICK) < 0)
		return OBJ_BAD;
	return type;
}

/*
 * Validates and send requested info back to the client. Any errors detected
 * are returned as they are detected.
 */
static void send_info(struct repository *r, struct packet_writer *writer,
		      struct string_list *oid_str_list,
		      struct requested_info *info)
{
	struct string_list_item *item;
	struct strbuf send_buffer = STRBUF_INIT;

	if (!oid_str_list->nr)
		return;

	if (info->size)
		packet_writer_write(writer, "size");

	for_each_string_list_item (item, oid_str_list) {
		const char *oid_str = item->string;
		struct object_id oid;
		size_t object_size;

		if (get_oid_hex_algop(oid_str, &oid, r->hash_algo) < 0) {
			packet_writer_error(
				writer,
				"object-info: protocol error, expected to get oid, not '%s'",
				oid_str);
			continue;
		}

		strbuf_addstr(&send_buffer, oid_str);

		/*
		 * Check the existence of the object first.
		 * If an object is not recognized by the server append SP to
		 * the response.
		 */
		if (get_object_info(r->objects, &oid, &object_size) <= OBJ_NONE) {
			strbuf_addstr(&send_buffer, " ");
			goto write;
		}

		if (info->size) {
			strbuf_addf(&send_buffer, " %"PRIuMAX,
				    (uintmax_t)object_size);
		}

write:
		packet_writer_write(writer, "%s", send_buffer.buf);
		strbuf_reset(&send_buffer);
	}
	strbuf_release(&send_buffer);
}

int cap_object_info(struct repository *r, struct packet_reader *request)
{
	struct requested_info info = { 0 };
	struct packet_writer writer;
	struct string_list oid_str_list = STRING_LIST_INIT_DUP;

	packet_writer_init(&writer, 1);

	while (packet_reader_read(request) == PACKET_READ_NORMAL) {
		if (!strcmp("size", request->line)) {
			info.size = 1;
			continue;
		}

		if (parse_oid(request->line, &oid_str_list))
			continue;

		packet_writer_error(&writer,
				    "object-info: unexpected line: '%s'",
				    request->line);
	}

	if (request->status != PACKET_READ_FLUSH) {
		packet_writer_error(
			&writer, "object-info: expected flush after arguments");
		die(_("object-info: expected flush after arguments"));
	}

	send_info(r, &writer, &oid_str_list, &info);

	string_list_clear(&oid_str_list, 1);

	packet_flush(1);

	return 0;
}