From 990f2dc1cf2039e8df080bca51af6f6a5c981619 Mon Sep 17 00:00:00 2001
From: Max Kellermann <max@musicpd.org>
Date: Tue, 1 Dec 2020 16:56:58 +0100
Subject: [PATCH] event/DeferEvent: use class IntrusiveList instead of
 boost::intrusive::list

---
 src/event/DeferEvent.cxx | 11 ++++-------
 src/event/DeferEvent.hxx | 27 +++++++++++++--------------
 src/event/Loop.cxx       | 22 +++++-----------------
 src/event/Loop.hxx       | 14 +++-----------
 4 files changed, 25 insertions(+), 49 deletions(-)

diff --git a/src/event/DeferEvent.cxx b/src/event/DeferEvent.cxx
index 7e50c660d..f8bfacb28 100644
--- a/src/event/DeferEvent.cxx
+++ b/src/event/DeferEvent.cxx
@@ -20,14 +20,11 @@
 #include "DeferEvent.hxx"
 #include "Loop.hxx"
 
-void
-DeferEvent::Cancel() noexcept
-{
-	loop.RemoveDeferred(*this);
-}
-
 void
 DeferEvent::Schedule() noexcept
 {
-	loop.AddDeferred(*this);
+	if (!IsPending())
+		loop.AddDeferred(*this);
+
+	assert(IsPending());
 }
diff --git a/src/event/DeferEvent.hxx b/src/event/DeferEvent.hxx
index 3f5804e5b..f1914fe08 100644
--- a/src/event/DeferEvent.hxx
+++ b/src/event/DeferEvent.hxx
@@ -21,8 +21,7 @@
 #define MPD_DEFER_EVENT_HXX
 
 #include "util/BindMethod.hxx"
-
-#include <boost/intrusive/list_hook.hpp>
+#include "util/IntrusiveList.hxx"
 
 class EventLoop;
 
@@ -34,10 +33,10 @@ class EventLoop;
  * This class is not thread-safe, all methods must be called from the
  * thread that runs the #EventLoop.
  */
-class DeferEvent final
-	: public boost::intrusive::list_base_hook<>
+class DeferEvent final : AutoUnlinkIntrusiveListHook
 {
 	friend class EventLoop;
+	friend class IntrusiveList<DeferEvent>;
 
 	EventLoop &loop;
 
@@ -51,23 +50,23 @@ public:
 	DeferEvent(const DeferEvent &) = delete;
 	DeferEvent &operator=(const DeferEvent &) = delete;
 
-	~DeferEvent() noexcept {
-		Cancel();
-	}
-
-	EventLoop &GetEventLoop() const noexcept {
+	auto &GetEventLoop() const noexcept {
 		return loop;
 	}
 
-	void Schedule() noexcept;
-	void Cancel() noexcept;
-
-private:
 	bool IsPending() const noexcept {
 		return is_linked();
 	}
 
-	void RunDeferred() noexcept {
+	void Schedule() noexcept;
+
+	void Cancel() noexcept {
+		if (IsPending())
+			unlink();
+	}
+
+private:
+	void Run() noexcept {
 		callback();
 	}
 };
diff --git a/src/event/Loop.cxx b/src/event/Loop.cxx
index de8b4445d..2a304f950 100644
--- a/src/event/Loop.cxx
+++ b/src/event/Loop.cxx
@@ -198,29 +198,17 @@ EventLoop::HandleTimers() noexcept
 void
 EventLoop::AddDeferred(DeferEvent &d) noexcept
 {
-	if (d.IsPending())
-		return;
-
-	deferred.push_back(d);
+	defer.push_back(d);
 	again = true;
 }
 
-void
-EventLoop::RemoveDeferred(DeferEvent &d) noexcept
-{
-	if (d.IsPending())
-		deferred.erase(deferred.iterator_to(d));
-}
-
 void
 EventLoop::RunDeferred() noexcept
 {
-	while (!deferred.empty() && !quit) {
-		auto &m = deferred.front();
-		assert(m.IsPending());
-
-		deferred.pop_front();
-		m.RunDeferred();
+	while (!defer.empty() && !quit) {
+		defer.pop_front_and_dispose([](DeferEvent *e){
+			e->Run();
+		});
 	}
 }
 
diff --git a/src/event/Loop.hxx b/src/event/Loop.hxx
index 59e4487b2..0d9868f10 100644
--- a/src/event/Loop.hxx
+++ b/src/event/Loop.hxx
@@ -79,11 +79,9 @@ class EventLoop final
 					   boost::intrusive::constant_time_size<false>>;
 	TimerSet timers;
 
-	using DeferList =
-		boost::intrusive::list<DeferEvent,
-				       boost::intrusive::base_hook<boost::intrusive::list_base_hook<>>,
-				       boost::intrusive::constant_time_size<false>>;
-	DeferList deferred;
+	using DeferList = IntrusiveList<DeferEvent>;
+
+	DeferList defer;
 
 	using IdleList = IntrusiveList<IdleEvent>;
 	IdleList idle;
@@ -214,12 +212,6 @@ public:
 	 */
 	void AddDeferred(DeferEvent &d) noexcept;
 
-	/**
-	 * Cancel a pending call to DeferEvent::RunDeferred().
-	 * However after returning, the call may still be running.
-	 */
-	void RemoveDeferred(DeferEvent &d) noexcept;
-
 #ifdef HAVE_THREADED_EVENT_LOOP
 	/**
 	 * Schedule a call to the InjectEvent.