From 33ba190bec97f30a8509d731d163e51e710f8518 Mon Sep 17 00:00:00 2001
From: Max Kellermann <mk@cm4all.com>
Date: Mon, 12 Nov 2018 22:01:47 +0100
Subject: [PATCH] event/TimerEvent: add ScheduleEarlier()

---
 src/event/TimerEvent.cxx | 7 +++++++
 src/event/TimerEvent.hxx | 9 +++++++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/event/TimerEvent.cxx b/src/event/TimerEvent.cxx
index e2fc384e2..52bf2cd5a 100644
--- a/src/event/TimerEvent.cxx
+++ b/src/event/TimerEvent.cxx
@@ -27,3 +27,10 @@ TimerEvent::Schedule(Event::Duration d) noexcept
 
 	loop.AddTimer(*this, d);
 }
+
+void
+TimerEvent::ScheduleEarlier(Event::Duration d) noexcept
+{
+	if (!IsPending() || loop.SteadyNow() + d < due)
+		Schedule(d);
+}
diff --git a/src/event/TimerEvent.hxx b/src/event/TimerEvent.hxx
index baadcdb4e..0fe775fac 100644
--- a/src/event/TimerEvent.hxx
+++ b/src/event/TimerEvent.hxx
@@ -53,8 +53,7 @@ class TimerEvent final
 
 public:
 	TimerEvent(EventLoop &_loop, Callback _callback) noexcept
-		:loop(_loop), callback(_callback) {
-	}
+		:loop(_loop), callback(_callback) {}
 
 	auto &GetEventLoop() const noexcept {
 		return loop;
@@ -66,6 +65,12 @@ public:
 
 	void Schedule(Event::Duration d) noexcept;
 
+	/**
+	 * Like Schedule(), but is a no-op if there is a due time
+	 * earlier than the given one.
+	 */
+	void ScheduleEarlier(Event::Duration d) noexcept;
+
 	void Cancel() noexcept {
 		unlink();
 	}