common: add simple json parse wrapper for the complete cases.

We're going to change the API on the more complete JSON parser, so
make and use a simple API for the easy cases.

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

common/json.c

@@ -585,6 +585,17 @@ again:
 	return toks;
 }
 
+jsmntok_t *json_parse_simple(const tal_t *ctx, const char *input, int len)
+{
+	bool valid;
+	jsmntok_t *toks;
+
+	toks = json_parse_input(ctx, input, len, &valid);
+	if (toks && !valid)
+		toks = tal_free(toks);
+	return toks;
+}
+
 const char *jsmntype_to_string(jsmntype_t t)
 {
 	switch (t) {

common/json.h

@@ -89,6 +89,10 @@ const jsmntok_t *json_get_arr(const jsmntok_t tok[], size_t index);
 jsmntok_t *json_parse_input(const tal_t *ctx,
 			    const char *input, int len, bool *valid);
 
+/* Simplified version of above which parses only a complete, valid
+ * JSON string */
+jsmntok_t *json_parse_simple(const tal_t *ctx, const char *input, int len);
+
 /* Convert a jsmntype_t enum to a human readable string. */
 const char *jsmntype_to_string(jsmntype_t t);
 

common/test/run-json.c

@@ -144,19 +144,18 @@ static void test_json_tok_size(void)
 
 	/* This should *not* parse! (used to give toks[0]->size == 2!) */
 	buf = "{ 'satoshi', '546' }";
-	toks = json_parse_input(tmpctx, buf, strlen(buf), &ok);
+	toks = json_parse_simple(tmpctx, buf, strlen(buf));
-	assert(!ok);
+	assert(!toks);
 }
 
 static void test_json_delve(void)
 {
 	const jsmntok_t *toks, *t;
 	char *buf;
-	bool ok;
 
 	buf = "{\"1\":\"one\", \"2\":\"two\", \"3\":[\"three\", {\"deeper\": 17}]}";
-	toks = json_parse_input(tmpctx, buf, strlen(buf), &ok);
+	toks = json_parse_simple(tmpctx, buf, strlen(buf));
-	assert(ok);
+	assert(toks);
 	assert(toks->size == 3);
 
 	t = json_delve(buf, toks, ".1");
@@ -227,8 +226,8 @@ static void test_json_delve(void)
 		"  }\n"
 		"}\n"
 		"\n";
-	toks = json_parse_input(tmpctx, buf, strlen(buf), &ok);
+	toks = json_parse_simple(tmpctx, buf, strlen(buf));
-	assert(ok);
+	assert(toks);
 	assert(toks->size == 4);
 
 	t = json_delve(buf, toks, ".rpcfile");

common/test/run-json_remove.c

@@ -148,9 +148,8 @@ static struct json *json_parse(const tal_t * ctx, const char *str)
 	struct json *j = tal(ctx, struct json);
 	j->buffer = tal_strdup(j, str);
 	convert_quotes(j->buffer);
-	bool ok;
+	j->toks = json_parse_simple(j, j->buffer, strlen(j->buffer));
-	j->toks = json_parse_input(j, j->buffer, strlen(j->buffer), &ok);
+	assert(j->toks);
-	assert(ok);
 	j->toks = json_tok_copy(j, j->toks);
 	return j;
 }

devtools/onion.c

@@ -204,7 +204,6 @@ static char *opt_set_node_id(const char *arg, struct node_id *node_id)
 static void runtest(const char *filename)
 {
 	const tal_t *ctx = tal(NULL, u8);
-	bool valid;
 	char *buffer = grab_file(ctx, filename);
 	const jsmntok_t *toks, *session_key_tok, *associated_data_tok, *gentok,
 		*hopstok, *hop, *payloadtok, *pubkeytok, *typetok, *oniontok, *decodetok;
@@ -217,8 +216,8 @@ static void runtest(const char *filename)
 	struct route_step *step;
 	char *hexprivkey;
 
-	toks = json_parse_input(ctx, buffer, strlen(buffer), &valid);
+	toks = json_parse_simple(ctx, buffer, strlen(buffer));
-	if (!valid)
+	if (!toks)
 		errx(1, "File is not a valid JSON file.");
 
 	gentok = json_get_member(buffer, toks, "generate");

plugins/libplugin.c

@@ -442,12 +442,12 @@ static const jsmntok_t *read_rpc_reply(const tal_t *ctx,
 				       int *reqlen)
 {
 	const jsmntok_t *toks;
-	bool valid;
 
 	*reqlen = read_json_from_rpc(plugin);
 
-	toks = json_parse_input(ctx, membuf_elems(&plugin->rpc_conn->mb), *reqlen, &valid);
+	toks = json_parse_simple(ctx,
-	if (!valid)
+				 membuf_elems(&plugin->rpc_conn->mb), *reqlen);
+	if (!toks)
 		plugin_err(plugin, "Malformed JSON reply '%.*s'",
 			   *reqlen, membuf_elems(&plugin->rpc_conn->mb));
 
@@ -648,7 +648,6 @@ static void rpc_conn_finished(struct io_conn *conn,
 
 static bool rpc_read_response_one(struct plugin *plugin)
 {
-	bool valid;
 	const jsmntok_t *toks, *jrtok;
 
 	/* For our convenience, lightningd always ends JSON requests with
@@ -656,15 +655,10 @@ static bool rpc_read_response_one(struct plugin *plugin)
 	if (!memmem(plugin->rpc_buffer, plugin->rpc_used, "\n\n", 2))
 		return false;
 
-	toks = json_parse_input(NULL, plugin->rpc_buffer, plugin->rpc_used,
+	toks = json_parse_simple(NULL, plugin->rpc_buffer, plugin->rpc_used);
-				&valid);
 	if (!toks) {
-		if (!valid) {
+		plugin_err(plugin, "Failed to parse RPC JSON response '%.*s'",
-			plugin_err(plugin, "Failed to parse RPC JSON response '%.*s'",
+			   (int)plugin->rpc_used, plugin->rpc_buffer);
-				   (int)plugin->rpc_used, plugin->rpc_buffer);
-			return false;
-		}
-		/* We need more. */
 		return false;
 	}