transport: drop remote object-info fields from transport struct

A remote object-info request needs three things: the transport for
contacting the remote, the list of oids to request, and a place to store
the output.

Rather than take these as function parameters, we take only the
transport object, and expect the caller to have placed the other two
into special fields in the transport struct. But this doesn't make much
sense. The set of oids and results are really only valid for one
request. There is no reason the transport would need to hang on to them
outside of the single function call.

Even though we save a few lines passing the parameters around through
the various vtable functions, the result is harder to understand (for
example, who is responsible for cleaning up results, and when should it
happen?). It also opens up the possibility of a subtle bug. A caller is
likely to point those fields to stack variables which could go out of
scope, and the transport struct would be left holding invalid pointers.

This is mostly harmless now, as we disconnect the transport immediately
after the sole caller of transport_fetch_object_info(). But conceptually
we could keep the transport open and make multiple fetch calls (and
reuse the same connection to the helper, to a remote HTTP server, and so
on).

So let's pull these out of the struct and pass them as function
parameters. It's a little more verbose, but I think more clearly
illustrates the intent. I've also tweaked a few function signatures to
mark the input oid array as const, since it is purely an input to the
function.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Pablo Sabater <pabloosabaterr@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/cat-file.c

@@ -724,10 +724,8 @@ static int get_remote_info(int argc,
 		goto cleanup;
 	}
 
-	gtransport->smart_options->object_info_oids = object_info_oids;
-
-	gtransport->smart_options->object_info_results = results;
-	retval = transport_fetch_object_info(gtransport);
+	retval = transport_fetch_object_info(gtransport, object_info_oids,
+					     results);
 cleanup:
 	transport_disconnect(gtransport);
 	return retval;

fetch-object-info.c

@@ -11,7 +11,7 @@
 /* Sends object-info command and its arguments into the request buffer. */
 static void send_object_info_request(const int fd_out,
 				     const struct string_list *server_options,
-				     struct oid_array *oids,
+				     const struct oid_array *oids,
 				     unsigned ask_size)
 {
 	struct strbuf req_buf = STRBUF_INIT;
@@ -49,7 +49,7 @@ static int parse_object_size(const char *s, size_t *res)
 
 void fetch_object_info(const enum protocol_version version,
 		       const struct string_list *server_options,
-		       struct oid_array *oids,
+		       const struct oid_array *oids,
 		       struct packet_reader *reader,
 		       struct fetch_object_info_results *results,
 		       const int stateless_rpc,

fetch-object-info.h

@@ -26,7 +26,7 @@ struct oid_array;
  */
 void fetch_object_info(enum protocol_version version,
 		       const struct string_list *server_options,
-		       struct oid_array *oids,
+		       const struct oid_array *oids,
 		       struct packet_reader *reader,
 		       struct fetch_object_info_results *results,
 		       int stateless_rpc,

transport-helper.c

@@ -784,11 +784,14 @@ static int fetch_refs(struct transport *transport,
 	return -1;
 }
 
-static int fetch_object_info_helper(struct transport *transport)
+static int fetch_object_info_helper(struct transport *transport,
+				    const struct oid_array *oids,
+				    struct fetch_object_info_results *results)
 {
 	get_helper(transport);
 	if (process_connect(transport, 0))
-		return transport->vtable->fetch_object_info(transport);
+		return transport->vtable->fetch_object_info(transport, oids,
+							    results);
 
 	die(_("object-info requires protocol v2"));
 }

transport-internal.h

@@ -7,6 +7,8 @@ struct ref;
 struct transport;
 struct strvec;
 struct transport_ls_refs_options;
+struct oid_array;
+struct fetch_object_info_results;
 
 struct transport_vtable {
 	/**
@@ -51,7 +53,9 @@ struct transport_vtable {
 	 *
 	 * Uses object-info capability of v2 protocol.
 	 */
-	int (*fetch_object_info)(struct transport *transport);
+	int (*fetch_object_info)(struct transport *transport,
+				 const struct oid_array *oids,
+				 struct fetch_object_info_results *results);
 
 	/**
 	 * Push the objects and refs. Send the necessary objects, and

transport.c

@@ -433,7 +433,9 @@ static int get_bundle_uri(struct transport *transport)
 				     transport->bundles, stateless_rpc);
 }
 
-static int fetch_object_info_via_pack(struct transport *transport)
+static int fetch_object_info_via_pack(struct transport *transport,
+				      const struct oid_array *oids,
+				      struct fetch_object_info_results *results)
 {
 	int ret = 0;
 	struct git_transport_data *data = transport->data;
@@ -450,9 +452,9 @@ static int fetch_object_info_via_pack(struct transport *transport)
 
 	fetch_object_info(data->version,
 			  transport->server_options,
-			  transport->smart_options->object_info_oids,
+			  oids,
 			  &reader,
-			  data->options.object_info_results,
+			  results,
 			  transport->stateless_rpc, data->fd[1]);
 
 	close(data->fd[0]);
@@ -465,11 +467,13 @@ static int fetch_object_info_via_pack(struct transport *transport)
 	return ret;
 }
 
-int transport_fetch_object_info(struct transport *transport)
+int transport_fetch_object_info(struct transport *transport,
+				const struct oid_array *oids,
+				struct fetch_object_info_results *results)
 {
 	if (!transport->vtable->fetch_object_info)
 		die(_("remote does not support object-info"));
-	return transport->vtable->fetch_object_info(transport);
+	return transport->vtable->fetch_object_info(transport, oids, results);
 }
 
 static int fetch_refs_via_pack(struct transport *transport,

transport.h

@@ -57,9 +57,6 @@ struct git_transport_options {
 	 * common commits to this oidset instead of fetching any packfiles.
 	 */
 	struct oidset *acked_commits;
-
-	struct oid_array *object_info_oids;
-	struct fetch_object_info_results *object_info_results;
 };
 
 enum transport_family {
@@ -317,7 +314,9 @@ int transport_fetch_refs(struct transport *transport, struct ref *refs);
 /*
  * Fetch the object info from remote
  */
-int transport_fetch_object_info(struct transport *transport);
+int transport_fetch_object_info(struct transport *transport,
+				const struct oid_array *oids,
+				struct fetch_object_info_results *results);
 
 /*
  * If this flag is set, unlocking will avoid to call non-async-signal-safe