timeout: oneshot timer support.

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

daemon/timeout.c

@@ -16,3 +16,39 @@ void refresh_timeout(struct lightningd_state *dstate, struct timeout *t)
 	timer_add(&dstate->timers, &t->timer,
 		  timeabs_add(time_now(), t->interval));
 }
+
+/* FIXME: Make all timers one-shot! */
+struct oneshot {
+	struct timeout timeout;
+	struct lightningd_state *dstate;
+	void (*cb)(void *);
+	void *arg;
+};
+
+static void remove_timer(struct oneshot *o)
+{
+	timer_del(&o->dstate->timers, &o->timeout.timer);
+}
+
+static void oneshot_done(struct oneshot *o)
+{
+	o->cb(o->arg);
+	tal_free(o);
+}
+
+struct oneshot *oneshot_timeout_(struct lightningd_state *dstate,
+				 const tal_t *ctx, unsigned int seconds,
+				 void (*cb)(void *), void *arg)
+{
+	struct oneshot *o = tal(ctx, struct oneshot);
+
+	o->dstate = dstate;
+	o->cb = cb;
+	o->arg = arg;
+
+	init_timeout(&o->timeout, seconds, oneshot_done, o);
+	refresh_timeout(dstate, &o->timeout);
+	tal_add_destructor(o, remove_timer);
+
+	return o;
+}

daemon/timeout.h

@@ -24,4 +24,13 @@ void refresh_timeout(struct lightningd_state *dstate, struct timeout *t);
 	init_timeout_((t), (interval),					\
 		     typesafe_cb(void, void *, (func), (arg)), (arg))
 
+/* tal_free this to disable timer. */
+struct oneshot *oneshot_timeout_(struct lightningd_state *dstate,
+				 const tal_t *ctx, unsigned int seconds,
+				 void (*cb)(void *), void *arg);
+
+#define oneshot_timeout(dstate, ctx, interval, func, arg)		\
+	oneshot_timeout_((dstate), (ctx), (interval),			\
+			 typesafe_cb(void, void *, (func), (arg)), (arg))
+
 #endif /* LIGHTNING_DAEMON_TIMEOUT_H */