libplugin: use NULL to imply "take prefix from cmd".

This avoids jsonrpc_request_start() double-evaluating its cmd arg.

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

Author: rustyrussell

plugins/commando.c

@@ -728,8 +728,7 @@ static struct command_result *forward_command(struct command *cmd,
 	/* params could be an array, so use low-level helper */
 	struct out_req *req;
 
-	req = jsonrpc_request_whole_object_start(cmd, method,
-						 json_id_prefix(tmpctx, cmd),
+	req = jsonrpc_request_whole_object_start(cmd, method, NULL,
 						 forward_reply, NULL);
 	json_add_tok(req->js, "params", params, buffer);
 	return send_outreq(req);

plugins/libplugin.c

@@ -273,25 +273,26 @@ static void disable_request_cb(struct command *cmd, struct out_req *out)
 	out->cmd = NULL;
 }
 
-const char *json_id_prefix(const tal_t *ctx, const struct command *cmd)
+/* Prefix is usually a cmd->id */
+static const char *json_id(const tal_t *ctx, struct plugin *plugin,
+			   const char *method, const char *prefix)
 {
+	const char *rawid;
+	int rawidlen;
+
 	/* Strip quotes! */
-	if (strstarts(cmd->id, "\"")) {
-		assert(strlen(cmd->id) >= 2);
-		assert(strends(cmd->id, "\""));
-		return tal_fmt(ctx, "%.*s/",
-			       (int)strlen(cmd->id) - 2, cmd->id + 1);
+	if (strstarts(prefix, "\"")) {
+		assert(strlen(prefix) >= 2);
+		assert(strends(prefix, "\""));
+		rawid = prefix + 1;
+		rawidlen = strlen(prefix) - 2;
+	} else {
+		rawid = prefix;
+		rawidlen = strlen(prefix);
 	}
-	return tal_fmt(ctx, "%s/", cmd->id);
-}
 
-static const char *append_json_id(const tal_t *ctx,
-				  struct plugin *plugin,
-				  const char *method,
-				  const char *prefix)
-{
-	return tal_fmt(ctx, "\"%s%s:%s#%"PRIu64"\"",
-		       prefix, plugin->id, method, plugin->next_outreq_id++);
+	return tal_fmt(ctx, "\"%.*s%s:%s#%"PRIu64"\"",
+		       rawidlen, rawid, plugin->id, method, plugin->next_outreq_id++);
 }
 
 static void destroy_out_req(struct out_req *out_req, struct plugin *plugin)
@@ -320,7 +321,7 @@ jsonrpc_request_start_(struct command *cmd,
 
 	assert(cmd);
 	out = tal(cmd, struct out_req);
-	out->id = append_json_id(out, cmd->plugin, method, id_prefix);
+	out->id = json_id(out, cmd->plugin, method, id_prefix ? id_prefix : cmd->id);
 	out->cmd = cmd;
 	out->cb = cb;
 	out->errcb = errcb;
@@ -704,7 +705,7 @@ static const jsmntok_t *sync_req(const tal_t *ctx,
 	const jsmntok_t *contents;
 	int reqlen;
 	struct json_out *jout = json_out_new(tmpctx);
-	const char *id = append_json_id(tmpctx, plugin, method, "init/");
+	const char *id = json_id(tmpctx, plugin, "init/", method);
 
 	json_out_start(jout, NULL, '{');
 	json_out_addstr(jout, "jsonrpc", "2.0");

plugins/libplugin.h

@@ -123,13 +123,10 @@ struct out_req *jsonrpc_request_start_(struct command *cmd,
 								       const jsmntok_t *result,
 								       void *arg),
 				       void *arg)
-	NON_NULL_ARGS(1, 2, 3, 5);
+	NON_NULL_ARGS(1, 2, 5);
 
-/* This variant has callbacks received whole obj, not "result" or
- * "error" members. */
-#define jsonrpc_request_start(cmd, method, cb, errcb, arg)	\
-	jsonrpc_request_start_((cmd), (method),		\
-		     json_id_prefix(tmpctx, (cmd)), NULL,		\
+#define jsonrpc_request_start(cmd, method, cb, errcb, arg)		\
+	jsonrpc_request_start_((cmd), (method), NULL, NULL,		\
 		     typesafe_cb_preargs(struct command_result *, void *, \
 					 (cb), (arg),			\
 					 struct command *command,	\
@@ -143,8 +140,7 @@ struct out_req *jsonrpc_request_start_(struct command *cmd,
 		     (arg))
 
 #define jsonrpc_request_with_filter_start(cmd, method, filter, cb, errcb, arg) \
-	jsonrpc_request_start_((cmd), (method),		\
-		     json_id_prefix(tmpctx, (cmd)), (filter),		\
+	jsonrpc_request_start_((cmd), (method),	NULL, (filter),		\
 		     typesafe_cb_preargs(struct command_result *, void *, \
 					 (cb), (arg),			\
 					 struct command *command,	\
@@ -160,7 +156,7 @@ struct out_req *jsonrpc_request_start_(struct command *cmd,
 /* This variant has callbacks received whole obj, not "result" or
  * "error" members.  It also doesn't start params{}. */
 #define jsonrpc_request_whole_object_start(cmd, method, id_prefix, cb, arg) \
-	jsonrpc_request_start_((cmd), (method), (id_prefix), NULL, \
+	jsonrpc_request_start_((cmd), (method), (id_prefix), NULL,	\
 			       typesafe_cb_preargs(struct command_result *, void *, \
 						   (cb), (arg),		\
 						   struct command *command, \
@@ -641,9 +637,6 @@ struct createonion_response *json_to_createonion_response(const tal_t *ctx,
 struct route_hop *json_to_route(const tal_t *ctx, const char *buffer,
 				const jsmntok_t *toks);
 
-/* Create a prefix (ending in /) for this cmd_id, if any. */
-const char *json_id_prefix(const tal_t *ctx, const struct command *cmd);
-
 void plugin_set_memleak_handler(struct plugin *plugin,
 				void (*mark_mem)(struct plugin *plugin,
 						 struct htable *memtable));

plugins/test/run-route-calc.c

@@ -161,9 +161,6 @@ void json_array_start(struct json_stream *js UNNEEDED, const char *fieldname UNN
 const jsmntok_t *json_get_member(const char *buffer UNNEEDED, const jsmntok_t tok[] UNNEEDED,
 				 const char *label UNNEEDED)
 { fprintf(stderr, "json_get_member called!\n"); abort(); }
-/* Generated stub for json_id_prefix */
-const char *json_id_prefix(const tal_t *ctx UNNEEDED, const struct command *cmd UNNEEDED)
-{ fprintf(stderr, "json_id_prefix called!\n"); abort(); }
 /* Generated stub for json_next */
 const jsmntok_t *json_next(const jsmntok_t *tok UNNEEDED)
 { fprintf(stderr, "json_next called!\n"); abort(); }

plugins/test/run-route-overlong.c

@@ -158,9 +158,6 @@ void json_array_start(struct json_stream *js UNNEEDED, const char *fieldname UNN
 const jsmntok_t *json_get_member(const char *buffer UNNEEDED, const jsmntok_t tok[] UNNEEDED,
 				 const char *label UNNEEDED)
 { fprintf(stderr, "json_get_member called!\n"); abort(); }
-/* Generated stub for json_id_prefix */
-const char *json_id_prefix(const tal_t *ctx UNNEEDED, const struct command *cmd UNNEEDED)
-{ fprintf(stderr, "json_id_prefix called!\n"); abort(); }
 /* Generated stub for json_next */
 const jsmntok_t *json_next(const jsmntok_t *tok UNNEEDED)
 { fprintf(stderr, "json_next called!\n"); abort(); }