From c28cbf4a6169a5fd869df72bee9cae5156b61fbd Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Sat, 8 Dec 2018 11:09:27 +1030
Subject: [PATCH] jsonrpc: remove ok pointer.

We can use the 'destructor-canary' trick instead.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 lightningd/jsonrpc.c | 21 ++++++++++-----------
 lightningd/jsonrpc.h |  1 -
 2 files changed, 10 insertions(+), 12 deletions(-)

diff --git a/lightningd/jsonrpc.c b/lightningd/jsonrpc.c
index 36d424b4a..f7dff296c 100644
--- a/lightningd/jsonrpc.c
+++ b/lightningd/jsonrpc.c
@@ -403,8 +403,6 @@ void command_success(struct command *cmd, struct json_stream *result)
 	assert(cmd);
 	assert(cmd->have_json_stream);
 	json_stream_append(result, " }\n\n");
-	if (cmd->ok)
-		*(cmd->ok) = true;
 
 	command_raw_complete(cmd, result);
 }
@@ -414,8 +412,6 @@ void command_failed(struct command *cmd, struct json_stream *result)
 	assert(cmd->have_json_stream);
 	/* Have to close error */
 	json_stream_append(result, " } }\n\n");
-	if (cmd->ok)
-		*(cmd->ok) = false;
 
 	command_raw_complete(cmd, result);
 }
@@ -551,7 +547,6 @@ static void parse_request(struct json_connection *jcon, const jsmntok_t tok[])
 			    json_tok_contents(jcon->buffer, id),
 			    json_tok_len(id));
 	c->mode = CMD_NORMAL;
-	c->ok = NULL;
 	list_add_tail(&jcon->commands, &c->list);
 	tal_add_destructor(c, destroy_command);
 
@@ -981,6 +976,12 @@ static bool json_tok_command(struct command *cmd, const char *name,
 	return false;
 }
 
+/* We add this destructor as a canary to detect cmd failing. */
+static void destroy_command_canary(struct command *cmd, bool *failed)
+{
+	*failed = true;
+}
+
 static void json_check(struct command *cmd,
 		       const char *buffer,
 		       const jsmntok_t *obj UNNEEDED,
@@ -988,7 +989,7 @@ static void json_check(struct command *cmd,
 {
 	jsmntok_t *mod_params;
 	const jsmntok_t *name_tok;
-	bool ok;
+	bool failed;
 	struct json_stream *response;
 
 	if (cmd->mode == CMD_USAGE) {
@@ -1010,13 +1011,11 @@ static void json_check(struct command *cmd,
 	json_tok_remove(&mod_params, (jsmntok_t *)name_tok, 1);
 
 	cmd->mode = CMD_CHECK;
-	/* FIXME(wythe): Maybe change "ok" to "failed" since that's really what
-	 * we're after and would be more clear. */
-	ok = true;
-	cmd->ok = &ok;
+	failed = false;
+	tal_add_destructor2(cmd, destroy_command_canary, &failed);
 	cmd->json_cmd->dispatch(cmd, buffer, mod_params, mod_params);
 
-	if (!ok)
+	if (failed)
 		return;
 
 	response = json_stream_success(cmd);
diff --git a/lightningd/jsonrpc.h b/lightningd/jsonrpc.h
index c7c35634e..ce5ae71ba 100644
--- a/lightningd/jsonrpc.h
+++ b/lightningd/jsonrpc.h
@@ -37,7 +37,6 @@ struct command {
 	enum command_mode mode;
 	/* This is created if mode is CMD_USAGE */
 	const char *usage;
-	bool *ok;
 	/* Have we started a json stream already?  For debugging. */
 	bool have_json_stream;
 };