lightningd: simplify and optimize plugin escape handling.

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

Author: rustyrussell

lightningd/plugin.c

@@ -514,49 +514,30 @@ static const char *plugin_log_handle(struct plugin *plugin,
 
 	call_notifier = (level == LOG_BROKEN || level == LOG_UNUSUAL)? true : false;
 
-	/* Unescape log message. */
-	tal_t *ctx = tal(NULL, char);
-	const char *log_escaped = plugin->buffer + msgtok->start;
-	const size_t log_escaped_len = msgtok->end - msgtok->start;
-	struct json_escape *esc = json_escape_string_(ctx, log_escaped, log_escaped_len);
-	const char *log_msg = json_escape_unescape(ctx, esc);
-
-	/* Find last line. */
-	const char *log_msg2 = log_msg;
-	const char *last_msg;
-	while (true) {
-		const char *msg_end = strchr(log_msg2, '\n');
-		if (!msg_end) {
-			break;
-		}
-		int msg_len = msg_end - log_msg2;
-		if (msg_len > 0) {
-			last_msg = log_msg2;
-		}
-		log_msg2 = msg_end + 1;
-	}
+	/* Only bother unescaping and splitting if it has \ */
+	if (memchr(plugin->buffer + msgtok->start, '\\', msgtok->end - msgtok->start)) {
+		const char *log_escaped = plugin->buffer + msgtok->start;
+		const size_t log_escaped_len = msgtok->end - msgtok->start;
+		struct json_escape *esc = json_escape_string_(tmpctx, log_escaped, log_escaped_len);
+		const char *log_msg = json_escape_unescape(tmpctx, esc);
+		char **lines;
 
-	/* Split to lines and log them separately. */
-	while (true) {
-		const char *msg_end = strchr(log_msg, '\n');
-		if (!msg_end) {
-			break;
-		}
-		int msg_len = msg_end - log_msg;
-		if (msg_len > 0) {
-			/* Call notifier only for the last message to avoid Python errors. */
+		lines = tal_strsplit(tmpctx, log_msg, "\n", STR_EMPTY_OK);
+
+		for (size_t i = 0; lines[i]; i++) {
 			bool call_notifier2 = call_notifier;
-			if (log_msg != last_msg) {
+			/* Call notifier only for the last message to avoid Python errors. */
+			if (lines[i+1] != NULL)
 				call_notifier2 = false;
-			}
 			/* FIXME: Let plugin specify node_id? */
-			log_(plugin->log, level, NULL, call_notifier2, "%.*s", msg_len, log_msg);
+			log_(plugin->log, level, NULL, call_notifier2, "%s", lines[i]);
 		}
-		log_msg = msg_end + 1;
+	} else {
+		log_(plugin->log, level, NULL, call_notifier, "%.*s",
+		     msgtok->end - msgtok->start,
+		     plugin->buffer + msgtok->start);
 	}
 
-	tal_free(ctx);
-
 	return NULL;
 }