lightningd: allow a more general wait_index increase.

We're not going to increment one at a time for bulk deletion of htlcs
when a channel closes.  There could be millions of HTLCs!

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

Author: rustyrussell

lightningd/wait.c

@@ -119,17 +119,17 @@ static void json_add_index(struct command *cmd,
 	json_object_end(response);
 }
 
-u64 wait_index_increment(struct lightningd *ld,
-			 enum wait_subsystem subsystem,
-			 enum wait_index index,
-			 ...)
+static u64 wait_index_bump(struct lightningd *ld,
+			   enum wait_subsystem subsystem,
+			   enum wait_index index,
+			   u64 num,
+			   va_list ap_master)
 {
 	struct waiter *i, *n;
-	va_list ap;
 	u64 *idxval = wait_index_ptr(ld, subsystem, index);
 
-	assert(!add_overflows_u64(*idxval, 1));
-	(*idxval)++;
+	assert(!add_overflows_u64(*idxval, num));
+	(*idxval) += num;
 
 	/* FIXME: We can optimize this!  It's always the max of the fields in
 	 * the table, *unless* we delete one.  So we can lazily write this on
@@ -142,6 +142,7 @@ u64 wait_index_increment(struct lightningd *ld,
 
 	list_for_each_safe(&ld->wait_commands, i, n, list) {
 		struct json_stream *response;
+		va_list ap;
 
 		if (*i->subsystem != subsystem)
 			continue;
@@ -151,7 +152,7 @@ u64 wait_index_increment(struct lightningd *ld,
 			continue;
 
 		response = json_stream_success(i->cmd);
-		va_start(ap, index);
+		va_copy(ap, ap_master);
 		json_add_index(i->cmd, response, subsystem, index, *idxval, &ap);
 		va_end(ap);
 		/* Delete before freeing */
@@ -162,6 +163,37 @@ u64 wait_index_increment(struct lightningd *ld,
 	return *idxval;
 }
 
+u64 wait_index_increment(struct lightningd *ld,
+			 enum wait_subsystem subsystem,
+			 enum wait_index index,
+			 ...)
+{
+	va_list ap;
+	u64 ret;
+
+	va_start(ap, index);
+	ret = wait_index_bump(ld, subsystem, index, 1, ap);
+	va_end(ap);
+
+	return ret;
+}
+
+void wait_index_increase(struct lightningd *ld,
+			 enum wait_subsystem subsystem,
+			 enum wait_index index,
+			 u64 num,
+			 ...)
+{
+	va_list ap;
+
+	if (num == 0)
+		return;
+
+	va_start(ap, num);
+	wait_index_bump(ld, subsystem, index, num, ap);
+	va_end(ap);
+}
+
 static struct command_result *param_subsystem(struct command *cmd,
 					      const char *name,
 					      const char *buffer,

lightningd/wait.h

@@ -49,6 +49,22 @@ u64 LAST_ARG_NULL wait_index_increment(struct lightningd *ld,
 				       enum wait_index index,
 				       ...);
 
+/**
+ * wait_index_increase - increase an index, tell waiters.
+ * @ld: the lightningd
+ * @subsystem: subsystem for index
+ * @index: which index
+ * @num: number to add (if > 0).
+ * ...: name/value pairs, followed by NULL.
+ *
+ * A more generic version if wait_index_increment: if num is 0 it's a noop.
+ */
+void LAST_ARG_NULL wait_index_increase(struct lightningd *ld,
+				       enum wait_subsystem subsystem,
+				       enum wait_index index,
+				       u64 num,
+				       ...);
+
 /* For passing in index parameters. */
 struct command_result *param_index(struct command *cmd, const char *name,
 				   const char *buffer,