lightningd: have json_stream_success start the "result" object.

"result" should always be an object (so that we can add new fields),
so make that implicit in json_stream_success.

This makes our primitives well-formed: we previously used NULL as our
fieldname when calling the first json_object_start, which is a hack
since we're actually in an object and the fieldname is 'result' (which
was already written by json_object_start).

There were only two cases which didn't do this:
1. dev-memdump returned an array.  No API guarantees on this.
2. shutdown returned a string.

I temporarily made shutdown return an empty object, which shouldn't
break anything, but I want to fix that later anyway.

Signed-off-by: Rusty Russell <[email protected]>

lightningd/chaintopology.c

@@ -143,7 +143,7 @@ static void broadcast_remainder(struct bitcoind *bitcoind,
 	if (txs->cursor == tal_count(txs->txs)) {
 		if (txs->cmd)
 			was_pending(command_success(txs->cmd,
-						    null_response(txs->cmd)));
+						    json_stream_success(txs->cmd)));
 		tal_free(txs);
 		return;
 	}
@@ -491,7 +491,6 @@ static struct command_result *json_feerates(struct command *cmd,
 	}
 
 	response = json_stream_success(cmd);
-	json_object_start(response, NULL);
 	json_object_start(response, json_feerate_style_name(*style));
 	for (size_t i = 0; i < ARRAY_SIZE(feerates); i++) {
 		if (!feerates[i])
@@ -522,8 +521,6 @@ static struct command_result *json_feerates(struct command *cmd,
 		json_object_end(response);
 	}
 
-	json_object_end(response);
-
 	return command_success(cmd, response);
 }
 

lightningd/connect_control.c

@@ -70,9 +70,7 @@ static struct command_result *connect_cmd_succeed(struct command *cmd,
 						  const struct node_id *id)
 {
 	struct json_stream *response = json_stream_success(cmd);
-	json_object_start(response, NULL);
 	json_add_node_id(response, "id", id);
-	json_object_end(response);
 	return command_success(cmd, response);
 }
 

lightningd/gossip_control.c

@@ -198,7 +198,6 @@ static void json_getnodes_reply(struct subd *gossip UNUSED, const u8 *reply,
 	}
 
 	response = json_stream_success(cmd);
-	json_object_start(response, NULL);
 	json_array_start(response, "nodes");
 
 	for (i = 0; i < tal_count(nodes); i++) {
@@ -229,7 +228,6 @@ static void json_getnodes_reply(struct subd *gossip UNUSED, const u8 *reply,
 		json_object_end(response);
 	}
 	json_array_end(response);
-	json_object_end(response);
 	was_pending(command_success(cmd, response));
 }
 
@@ -274,9 +272,7 @@ static void json_getroute_reply(struct subd *gossip UNUSED, const u8 *reply, con
 	}
 
 	response = json_stream_success(cmd);
-	json_object_start(response, NULL);
 	json_add_route(response, "route", hops, tal_count(hops));
-	json_object_end(response);
 	was_pending(command_success(cmd, response));
 }
 
@@ -436,7 +432,6 @@ static void json_listchannels_reply(struct subd *gossip UNUSED, const u8 *reply,
 			 req, -1, 0, json_listchannels_reply, linfo);
 	} else {
 		json_array_end(linfo->response);
-		json_object_end(linfo->response);
 		was_pending(command_success(linfo->cmd, linfo->response));
 	}
 }
@@ -462,7 +457,6 @@ static struct command_result *json_listchannels(struct command *cmd,
 
 	/* Start JSON response, then we stream. */
 	linfo->response = json_stream_success(cmd);
-	json_object_start(linfo->response, NULL);
 	json_array_start(linfo->response, "channels");
 
 	req = towire_gossip_getchannels_request(cmd, linfo->id, linfo->source,
@@ -501,9 +495,7 @@ static void json_scids_reply(struct subd *gossip UNUSED, const u8 *reply,
 	}
 
 	response = json_stream_success(cmd);
-	json_object_start(response, NULL);
 	json_add_bool(response, "complete", complete);
-	json_object_end(response);
 	was_pending(command_success(cmd, response));
 }
 
@@ -573,7 +565,7 @@ json_dev_send_timestamp_filter(struct command *cmd,
 	msg = towire_gossip_send_timestamp_filter(NULL, id, *first, *range);
 	subd_send_msg(cmd->ld->gossip, take(msg));
 
-	return command_success(cmd, null_response(cmd));
+	return command_success(cmd, json_stream_success(cmd));
 }
 
 static const struct json_command dev_send_timestamp_filter = {
@@ -609,7 +601,6 @@ static void json_channel_range_reply(struct subd *gossip UNUSED, const u8 *reply
 	}
 
 	response = json_stream_success(cmd);
-	json_object_start(response, NULL);
 	/* As this is a dev interface, we don't bother saving and
 	 * returning all the replies, just the final one. */
 	json_add_num(response, "final_first_block", final_first_block);
@@ -619,7 +610,6 @@ static void json_channel_range_reply(struct subd *gossip UNUSED, const u8 *reply
 	for (size_t i = 0; i < tal_count(scids); i++)
 		json_add_short_channel_id(response, NULL, &scids[i]);
 	json_array_end(response);
-	json_object_end(response);
 	was_pending(command_success(cmd, response));
 }
 
@@ -671,7 +661,7 @@ json_dev_set_max_scids_encode_size(struct command *cmd,
 	msg = towire_gossip_dev_set_max_scids_encode_size(NULL, *max);
 	subd_send_msg(cmd->ld->gossip, take(msg));
 
-	return command_success(cmd, null_response(cmd));
+	return command_success(cmd, json_stream_success(cmd));
 }
 
 static const struct json_command dev_set_max_scids_encode_size = {
@@ -692,7 +682,7 @@ static struct command_result *json_dev_suppress_gossip(struct command *cmd,
 
 	subd_send_msg(cmd->ld->gossip, take(towire_gossip_dev_suppress(NULL)));
 
-	return command_success(cmd, null_response(cmd));
+	return command_success(cmd, json_stream_success(cmd));
 }
 
 static const struct json_command dev_suppress_gossip = {
@@ -720,7 +710,7 @@ static void dev_compact_gossip_store_reply(struct subd *gossip UNUSED,
 		was_pending(command_fail(cmd, LIGHTNINGD,
 					 "gossip_compact_store failed"));
 	else
-		was_pending(command_success(cmd, null_response(cmd)));
+		was_pending(command_success(cmd, json_stream_success(cmd)));
 }
 
 static struct command_result *json_dev_compact_gossip_store(struct command *cmd,

lightningd/invoice.c

@@ -46,7 +46,6 @@ static const char *invoice_status_str(const struct invoice_details *inv)
 static void json_add_invoice(struct json_stream *response,
 			     const struct invoice_details *inv)
 {
-	json_object_start(response, NULL);
 	json_add_escaped_string(response, "label", inv->label);
 	json_add_string(response, "bolt11", inv->bolt11);
 	json_add_hex(response, "payment_hash", &inv->rhash, sizeof(inv->rhash));
@@ -66,8 +65,6 @@ static void json_add_invoice(struct json_stream *response,
 		json_add_string(response, "description", inv->description);
 
 	json_add_u64(response, "expires_at", inv->expiry_time);
-
-	json_object_end(response);
 }
 
 static struct command_result *tell_waiter(struct command *cmd,
@@ -86,6 +83,7 @@ static struct command_result *tell_waiter(struct command *cmd,
 		response = json_stream_fail(cmd, -2,
 					    "invoice expired during wait");
 		json_add_invoice(response, details);
+		json_object_end(response);
 		return command_failed(cmd, response);
 	}
 }
@@ -512,7 +510,6 @@ static void gossipd_incoming_channels_reply(struct subd *gossipd,
 	details = wallet_invoice_details(info, wallet, invoice);
 
 	response = json_stream_success(info->cmd);
-	json_object_start(response, NULL);
 	json_add_hex(response, "payment_hash", details->rhash.u.u8,
 		     sizeof(details->rhash));
 	json_add_u64(response, "expires_at", details->expiry_time);
@@ -538,7 +535,6 @@ static void gossipd_incoming_channels_reply(struct subd *gossipd,
 					"No channels have sufficient"
 					" incoming capacity");
 	}
-	json_object_end(response);
 
 	was_pending(command_success(info->cmd, response));
 }
@@ -809,15 +805,19 @@ static void json_add_invoices(struct json_stream *response,
 		struct invoice invoice;
 		if (wallet_invoice_find_by_label(wallet, &invoice, label)) {
 			details = wallet_invoice_details(response, wallet, invoice);
+			json_object_start(response, NULL);
 			json_add_invoice(response, details);
+			json_object_end(response);
 		}
 		return;
 	}
 
 	memset(&it, 0, sizeof(it));
 	while (wallet_invoice_iterate(wallet, &it)) {
 		details = wallet_invoice_iterator_deref(response, wallet, &it);
+		json_object_start(response, NULL);
 		json_add_invoice(response, details);
+		json_object_end(response);
 	}
 }
 
@@ -834,11 +834,9 @@ static struct command_result *json_listinvoices(struct command *cmd,
 		   NULL))
 		return command_param_failed();
 	response = json_stream_success(cmd);
-	json_object_start(response, NULL);
 	json_array_start(response, "invoices");
 	json_add_invoices(response, wallet, label);
 	json_array_end(response);
-	json_object_end(response);
 	return command_success(cmd, response);
 }
 
@@ -918,7 +916,7 @@ static struct command_result *json_delexpiredinvoice(struct command *cmd,
 
 	wallet_invoice_delete_expired(cmd->ld->wallet, *maxexpirytime);
 
-	return command_success(cmd, null_response(cmd));
+	return command_success(cmd, json_stream_success(cmd));
 }
 static const struct json_command delexpiredinvoice_command = {
 	"delexpiredinvoice",
@@ -1069,8 +1067,6 @@ static struct command_result *json_decodepay(struct command *cmd,
 	}
 
 	response = json_stream_success(cmd);
-	json_object_start(response, NULL);
-
 	json_add_string(response, "currency", b11->chain->bip173_name);
 	json_add_u64(response, "created_at", b11->timestamp);
 	json_add_u64(response, "expiry", b11->expiry);
@@ -1151,7 +1147,6 @@ static struct command_result *json_decodepay(struct command *cmd,
 	json_add_string(response, "signature",
                         type_to_string(cmd, secp256k1_ecdsa_signature,
                                        &b11->sig));
-	json_object_end(response);
 	return command_success(cmd, response);
 }
 

lightningd/jsonrpc.c

@@ -182,16 +182,12 @@ static struct command_result *json_stop(struct command *cmd,
 					const jsmntok_t *obj UNNEEDED,
 					const jsmntok_t *params)
 {
-	struct json_stream *response;
-
 	if (!param(cmd, buffer, params, NULL))
 		return command_param_failed();
 
 	/* This can't have closed yet! */
 	cmd->jcon->stop = true;
-	response = json_stream_success(cmd);
-	json_add_string(response, NULL, "Shutting down");
-	return command_success(cmd, response);
+	return command_success(cmd, json_stream_success(cmd));
 }
 
 static const struct json_command stop_command = {
@@ -219,9 +215,7 @@ static struct command_result *json_rhash(struct command *cmd,
 	/* Hash in place. */
 	sha256(secret, secret, sizeof(*secret));
 	response = json_stream_success(cmd);
-	json_object_start(response, NULL);
 	json_add_hex(response, "rhash", secret, sizeof(*secret));
-	json_object_end(response);
 	return command_success(cmd, response);
 }
 
@@ -241,9 +235,7 @@ struct slowcmd {
 
 static void slowcmd_finish(struct slowcmd *sc)
 {
-	json_object_start(sc->js, NULL);
 	json_add_num(sc->js, "msec", *sc->msec);
-	json_object_end(sc->js);
 	was_pending(command_success(sc->cmd, sc->js));
 }
 
@@ -388,14 +380,12 @@ static struct command_result *json_help(struct command *cmd,
 	asort(commands, tal_count(commands), compare_commands_name, NULL);
 
 	response = json_stream_success(cmd);
-	json_object_start(response, NULL);
 	json_array_start(response, "help");
 	for (size_t i = 0; i < tal_count(commands); i++) {
 		if (!one_cmd || one_cmd == commands[i])
 			json_add_help_command(cmd, response, commands[i]);
 	}
 	json_array_end(response);
-	json_object_end(response);
 
 	return command_success(cmd, response);
 }
@@ -412,16 +402,6 @@ static const struct json_command *find_cmd(const struct jsonrpc *rpc,
 	return NULL;
 }
 
-struct json_stream *null_response(struct command *cmd)
-{
-	struct json_stream *response;
-
-	response = json_stream_success(cmd);
-	json_object_start(response, NULL);
-	json_object_end(response);
-	return response;
-}
-
 /* This can be called directly on shutdown, even with unfinished cmd */
 static void destroy_command(struct command *cmd)
 {
@@ -451,7 +431,7 @@ struct command_result *command_success(struct command *cmd,
 {
 	assert(cmd);
 	assert(cmd->have_json_stream);
-	json_stream_append(result, " }\n\n");
+	json_stream_append(result, " } }\n\n");
 
 	return command_raw_complete(cmd, result);
 }
@@ -543,6 +523,7 @@ struct json_stream *json_stream_success(struct command *cmd)
 {
 	struct json_stream *r = json_start(cmd);
 	json_stream_append(r, "\"result\" : ");
+	json_object_start(r, NULL);
 	return r;
 }
 
@@ -568,6 +549,7 @@ struct json_stream *json_stream_fail(struct command *cmd,
 	struct json_stream *r = json_stream_fail_nodata(cmd, code, errmsg);
 
 	json_stream_append(r, ", \"data\" : ");
+	json_object_start(r, NULL);
 	return r;
 }
 
@@ -1169,9 +1151,7 @@ static struct command_result *json_check(struct command *cmd,
 		return res;
 
 	response = json_stream_success(cmd);
-	json_object_start(response, NULL);
 	json_add_string(response, "command_to_check", cmd->json_cmd->name);
-	json_object_end(response);
 	return command_success(cmd, response);
 }
 

lightningd/jsonrpc.h

@@ -77,7 +77,7 @@ struct jsonrpc_request {
 };
 
 /**
- * json_stream_success - start streaming a successful json result.
+ * json_stream_success - start streaming a successful json result object.
  * @cmd: the command we're running.
  *
  * The returned value should go to command_success() when done.
@@ -86,13 +86,14 @@ struct jsonrpc_request {
 struct json_stream *json_stream_success(struct command *cmd);
 
 /**
- * json_stream_fail - start streaming a failed json result.
+ * json_stream_fail - start streaming a failed json result, with data object.
  * @cmd: the command we're running.
  * @code: the error code from common/jsonrpc_errors.h
  * @errmsg: the error string.
  *
  * The returned value should go to command_failed() when done;
  * json_add_* will be placed into the 'data' field of the 'error' JSON reply.
+ * You need to json_object_end() once you're done!
  */
 struct json_stream *json_stream_fail(struct command *cmd,
 				     int code,
@@ -110,12 +111,11 @@ struct json_stream *json_stream_fail_nodata(struct command *cmd,
 					    int code,
 					    const char *errmsg);
 
-struct json_stream *null_response(struct command *cmd);
-
 /* These returned values are never NULL. */
 struct command_result *command_success(struct command *cmd,
 				       struct json_stream *response)
 	 WARN_UNUSED_RESULT;
+
 struct command_result *command_failed(struct command *cmd,
 				      struct json_stream *result)
 	 WARN_UNUSED_RESULT;

lightningd/log.c

@@ -732,12 +732,10 @@ static struct command_result *json_getlog(struct command *cmd,
 	response = json_stream_success(cmd);
 	/* Suppress logging for this stream, to not bloat io logs */
 	json_stream_log_suppress_for_cmd(response, cmd);
-	json_object_start(response, NULL);
 	json_add_time(response, "created_at", log_init_time(lr)->ts);
 	json_add_num(response, "bytes_used", (unsigned int) log_used(lr));
 	json_add_num(response, "bytes_max", (unsigned int) log_max_mem(lr));
 	json_add_log(response, lr, *minlevel);
-	json_object_end(response);
 	return command_success(cmd, response);
 }