common: add json_dup_contents() to duplicate toks and buffer.

We do this in several places, might as well make it common code.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Author: rustyrussell

common/json_parse.c

@@ -667,3 +667,13 @@ json_tok_channel_id(const char *buffer, const jsmntok_t *tok,
 	return hex_decode(buffer + tok->start, tok->end - tok->start,
 			  cid, sizeof(*cid));
 }
+
+void json_dup_contents(const tal_t *ctx,
+		       const char *buffer,
+		       const jsmntok_t *tok,
+		       const char **new_buffer,
+		       const jsmntok_t **new_toks)
+{
+	*new_buffer = tal_dup_arr(ctx, char, buffer, tok->end, 0);
+	*new_toks = tal_dup_arr(ctx, jsmntok_t, tok, json_next(tok) - tok, 0);
+}

common/json_parse.h

@@ -135,6 +135,13 @@ const char *json_scan(const tal_t *ctx,
 		      const char *guide,
 		      ...);
 
+/* Duplicate the tok(s) and buffer required (don't assume they're tal objects!) */
+void json_dup_contents(const tal_t *ctx,
+		       const char *buffer,
+		       const jsmntok_t *tok,
+		       const char **new_buffer,
+		       const jsmntok_t **new_toks);
+
 /* eg. JSON_SCAN(json_to_bool, &boolvar) */
 #define JSON_SCAN(fmt, var)						\
 	json_scan,							\

common/test/run-features.c

@@ -1,6 +1,7 @@
 #include "config.h"
 #include "../features.c"
 #include "../memleak.c"
+#include <bitcoin/script.h>
 #include <ccan/mem/mem.h>
 #include <common/setup.h>
 

lightningd/jsonrpc.c

@@ -991,8 +991,8 @@ rpc_command_hook_callback(struct rpc_command_hook_payload *p,
 	if (tok) {
 		/* We need to make copies here, as buffer and tokens
 		 * can be reused. */
-		p->custom_replace = json_tok_copy(p, tok);
-		p->custom_buffer = tal_dup_talarr(p, char, buffer);
+		json_dup_contents(p, buffer, tok,
+				  &p->custom_buffer, &p->custom_replace);
 		return true;
 	}
 
@@ -1139,8 +1139,9 @@ parse_request(struct json_connection *jcon, const jsmntok_t tok[])
 	rpc_hook = tal(c, struct rpc_command_hook_payload);
 	rpc_hook->cmd = c;
 	/* Duplicate since we might outlive the connection */
-	rpc_hook->buffer = tal_dup_talarr(rpc_hook, char, jcon->buffer);
-	rpc_hook->request = tal_dup_talarr(rpc_hook, jsmntok_t, tok);
+	json_dup_contents(rpc_hook, jcon->buffer, tok,
+			  &rpc_hook->buffer,
+			  &rpc_hook->request);
 
 	/* NULL the custom_ values for the hooks */
 	rpc_hook->custom_result = NULL;