Merge pull request #86 from vibe-d/lazy_init

Lazy driver initialization

dub.sdl

@@ -8,7 +8,7 @@ targetType "library"
 libs "anl" "resolv" platform="linux"
 libs "ws2_32" "user32" platform="windows-dmd"
 
-dependency "taggedalgebraic" version="~>0.10.4"
+dependency "taggedalgebraic" version="~>0.10.12"
 
 configuration "epoll" {
 	platforms "linux"

source/eventcore/core.d

@@ -7,6 +7,7 @@ import eventcore.drivers.posix.epoll;
 import eventcore.drivers.posix.kqueue;
 import eventcore.drivers.libasync;
 import eventcore.drivers.winapi.driver;
+import eventcore.internal.utils : mallocT, freeT;
 
 version (EventcoreEpollDriver) alias NativeEventDriver = EpollEventDriver;
 else version (EventcoreKqueueDriver) alias NativeEventDriver = KqueueEventDriver;
@@ -19,8 +20,11 @@ else alias NativeEventDriver = EventDriver;
 @safe @nogc nothrow {
 	static if (is(NativeEventDriver == EventDriver))
 		assert(s_driver !is null, "setupEventDriver() was not called for this thread.");
-	else
+	else {
-		assert(s_driver !is null, "eventcore.core static constructor didn't run!?");
+		if (!s_driver) {
+			s_driver = mallocT!NativeEventDriver();
+		}
+	}
 	return s_driver;
 }
 
@@ -30,7 +34,6 @@ static if (!is(NativeEventDriver == EventDriver)) {
 		if (!s_isMainThread) {
 			if (!s_initCount++) {
 				assert(s_driver is null);
-				s_driver = new NativeEventDriver;
 			}
 		}
 	}
@@ -38,15 +41,18 @@ static if (!is(NativeEventDriver == EventDriver)) {
 	static ~this()
 	{
 		if (!s_isMainThread) {
-			if (!--s_initCount)
+			if (!--s_initCount) {
-				s_driver.dispose();
+				if (s_driver) {
+					s_driver.dispose();
+					freeT(s_driver);
+				}
+			}
 		}
 	}
 
 	shared static this()
 	{
 		if (!s_initCount++) {
-			s_driver = new NativeEventDriver;
 			s_isMainThread = true;
 		}
 	}
@@ -54,7 +60,10 @@ static if (!is(NativeEventDriver == EventDriver)) {
 	shared static ~this()
 	{
 		if (!--s_initCount) {
-			s_driver.dispose();
+			if (s_driver) {
+				s_driver.dispose();
+				freeT(s_driver);
+			}
 		}
 	}
 } else {

source/eventcore/driver.d

@@ -352,20 +352,42 @@ interface EventDriverSockets {
 
 	/** Retrieves a reference to a user-defined value associated with a descriptor.
 	*/
-	@property final ref T userData(T, FD)(FD descriptor)
+	@property final ref T userData(T, FD)(FD descriptor) @trusted @nogc
-	@trusted {
+		if (hasNoGCLifetime!T)
+	{
+		import std.conv : emplace;
+		static void init(void* ptr) @nogc { emplace(cast(T*)ptr); }
+		static void destr(void* ptr) @nogc { destroy(*cast(T*)ptr); }
+		return *cast(T*)rawUserData(descriptor, T.sizeof, &init, &destr);
+	}
+	/// ditto
+	deprecated("Only @nogc constructible and destructible user data allowed.")
+	@property final ref T userData(T, FD)(FD descriptor) @trusted
+		if (!hasNoGCLifetime!T)
+	{
 		import std.conv : emplace;
 		static void init(void* ptr) { emplace(cast(T*)ptr); }
 		static void destr(void* ptr) { destroy(*cast(T*)ptr); }
-		return *cast(T*)rawUserData(descriptor, T.sizeof, &init, &destr);
+		static if (__traits(compiles, () nothrow { init(null); destr(null); }))
+			alias F = void function(void*) @nogc nothrow;
+		else alias F = void function(void*) @nogc;
+		return *cast(T*)rawUserData(descriptor, T.sizeof, cast(F)&init, cast(F)&destr);
 	}
 
 	/// Low-level user data access. Use `getUserData` instead.
-	protected void* rawUserData(StreamSocketFD descriptor, size_t size, DataInitializer initialize, DataInitializer destroy) @system;
+	protected void* rawUserData(StreamSocketFD descriptor, size_t size, DataInitializer initialize, DataInitializer destroy) @system @nogc;
 	/// ditto
-	protected void* rawUserData(StreamListenSocketFD descriptor, size_t size, DataInitializer initialize, DataInitializer destroy) @system;
+	protected void* rawUserData(StreamListenSocketFD descriptor, size_t size, DataInitializer initialize, DataInitializer destroy) @system @nogc;
 	/// ditto
-	protected void* rawUserData(DatagramSocketFD descriptor, size_t size, DataInitializer initialize, DataInitializer destroy) @system;
+	protected void* rawUserData(DatagramSocketFD descriptor, size_t size, DataInitializer initialize, DataInitializer destroy) @system @nogc;
+}
+
+enum hasNoGCLifetime(T) = __traits(compiles, () @nogc @trusted { import std.conv : emplace; T b = void; emplace!T(&b); destroy(b); });
+unittest {
+	static struct S1 {}
+	static struct S2 { ~this() { new int; } }
+	static assert(hasNoGCLifetime!S1);
+	static assert(!hasNoGCLifetime!S2);
 }
 
 
@@ -642,7 +664,7 @@ alias EventCallback = void delegate(EventID);
 alias SignalCallback = void delegate(SignalListenID, SignalStatus, int);
 alias TimerCallback = void delegate(TimerID);
 alias FileChangesCallback = void delegate(WatcherID, in ref FileChange change);
-@system alias DataInitializer = void function(void*);
+@system alias DataInitializer = void function(void*) @nogc;
 
 enum ExitReason {
 	timeout,

source/eventcore/drivers/posix/dns.d

@@ -43,7 +43,7 @@ final class EventDriverDNS_GAI(Events : EventDriverEvents, Signals : EventDriver
 	}
 
 	this(Events events, Signals signals)
-	{
+	@nogc {
 		m_events = events;
 		setupEvent();
 	}
@@ -139,7 +139,7 @@ final class EventDriverDNS_GAI(Events : EventDriverEvents, Signals : EventDriver
 	}
 
 	private void setupEvent()
-	{
+	@nogc {
 		if (m_event == EventID.invalid) {
 			m_event = m_events.createInternal();
 			m_events.wait(m_event, &onDNSSignal);

source/eventcore/drivers/posix/driver.d

@@ -64,16 +64,16 @@ final class PosixEventDriver(Loop : PosixEventLoop) : EventDriver {
 	}
 
 	this()
-	{
+	@nogc @trusted {
-		m_loop = new Loop;
+		m_loop = mallocT!Loop;
-		m_sockets = new SocketsDriver(m_loop);
+		m_sockets = mallocT!SocketsDriver(m_loop);
-		m_events = new EventsDriver(m_loop, m_sockets);
+		m_events = mallocT!EventsDriver(m_loop, m_sockets);
-		m_signals = new SignalsDriver(m_loop);
+		m_signals = mallocT!SignalsDriver(m_loop);
-		m_timers = new TimerDriver;
+		m_timers = mallocT!TimerDriver;
-		m_core = new CoreDriver(m_loop, m_timers, m_events);
+		m_core = mallocT!CoreDriver(m_loop, m_timers, m_events);
-		m_dns = new DNSDriver(m_events, m_signals);
+		m_dns = mallocT!DNSDriver(m_events, m_signals);
-		m_files = new FileDriver(m_events);
+		m_files = mallocT!FileDriver(m_events);
-		m_watchers = new WatcherDriver(m_events);
+		m_watchers = mallocT!WatcherDriver(m_events);
 	}
 
 	// force overriding these in the (final) sub classes to avoid virtual calls
@@ -95,7 +95,19 @@ final class PosixEventDriver(Loop : PosixEventLoop) : EventDriver {
 		m_dns.dispose();
 		m_core.dispose();
 		m_loop.dispose();
-		m_loop = null;
+
+		try () @trusted {
+				freeT(m_watchers);
+				freeT(m_files);
+				freeT(m_dns);
+				freeT(m_core);
+				freeT(m_timers);
+				freeT(m_signals);
+				freeT(m_events);
+				freeT(m_sockets);
+				freeT(m_loop);
+			} ();
+		catch (Exception e) assert(false, e.msg);
 	}
 }
 
@@ -121,29 +133,32 @@ final class PosixEventDriverCore(Loop : PosixEventLoop, Timers : EventDriverTime
 		ConsumableQueue!(Tuple!(ThreadCallback, intptr_t)) m_threadCallbacks;
 	}
 
-	protected this(Loop loop, Timers timers, Events events)
+	this(Loop loop, Timers timers, Events events)
-	{
+	@nogc {
 		m_loop = loop;
 		m_timers = timers;
 		m_events = events;
 		m_wakeupEvent = events.createInternal();
 
 		static if (__VERSION__ >= 2074)
-			m_threadCallbackMutex = new shared Mutex;
+			m_threadCallbackMutex = mallocT!(shared(Mutex));
 		else {
-			() @trusted { m_threadCallbackMutex = cast(shared)new Mutex; } ();
+			() @trusted { m_threadCallbackMutex = cast(shared)mallocT!Mutex; } ();
 		}
 
-		m_threadCallbacks = new ConsumableQueue!(Tuple!(ThreadCallback, intptr_t));
+		m_threadCallbacks = mallocT!(ConsumableQueue!(Tuple!(ThreadCallback, intptr_t)));
 		m_threadCallbacks.reserve(1000);
 	}
 
-	protected final void dispose()
+	final void dispose()
 	{
 		executeThreadCallbacks();
 		m_events.releaseRef(m_wakeupEvent);
-		atomicStore(m_threadCallbackMutex, null);
 		m_wakeupEvent = EventID.invalid; // FIXME: this needs to be synchronized!
+		try {
+			() @trusted { freeT(m_threadCallbackMutex); } ();
+			() @trusted { freeT(m_threadCallbacks); } ();
+		} catch (Exception e) assert(false, e.msg);
 	}
 
 	@property size_t waiterCount() const { return m_loop.m_waiterCount + m_timers.pendingCount; }
@@ -274,11 +289,11 @@ package class PosixEventLoop {
 	protected abstract bool doProcessEvents(Duration dur);
 
 	/// Registers the FD for general notification reception.
-	protected abstract void registerFD(FD fd, EventMask mask, bool edge_triggered = true);
+	protected abstract void registerFD(FD fd, EventMask mask, bool edge_triggered = true) @nogc;
 	/// Unregisters the FD for general notification reception.
-	protected abstract void unregisterFD(FD fd, EventMask mask);
+	protected abstract void unregisterFD(FD fd, EventMask mask) @nogc;
 	/// Updates the event mask to use for listening for notifications.
-	protected abstract void updateFD(FD fd, EventMask old_mask, EventMask new_mask, bool edge_triggered = true);
+	protected abstract void updateFD(FD fd, EventMask old_mask, EventMask new_mask, bool edge_triggered = true) @nogc;
 
 	final protected void notify(EventType evt)(FD fd)
 	{
@@ -342,7 +357,7 @@ package class PosixEventLoop {
 	}
 
 	package final void* rawUserDataImpl(size_t descriptor, size_t size, DataInitializer initialize, DataInitializer destroy)
-	@system {
+	@system @nogc {
 		FDSlot* fds = &m_fds[descriptor].common;
 		assert(fds.userDataDestructor is null || fds.userDataDestructor is destroy,
 			"Requesting user data with differing type (destructor).");

source/eventcore/drivers/posix/epoll.d

@@ -5,7 +5,7 @@
 	numbers of concurrently open sockets.
 */
 module eventcore.drivers.posix.epoll;
-@safe: /*@nogc:*/ nothrow:
+@safe @nogc nothrow:
 
 version (linux):
 
@@ -22,17 +22,18 @@ static if (!is(typeof(SOCK_CLOEXEC)))
 	enum SOCK_CLOEXEC = 0x80000;
 
 final class EpollEventLoop : PosixEventLoop {
-@safe: nothrow:
+@safe nothrow:
 
 	private {
 		int m_epoll;
-		epoll_event[] m_events;
+		epoll_event[100] m_events;
 	}
 
 	this()
-	{
+	@nogc {
-		m_epoll = () @trusted { return epoll_create1(SOCK_CLOEXEC); } ();
+		assumeSafeNoGC({
-		m_events.length = 100;
+			m_epoll = epoll_create1(SOCK_CLOEXEC);
+		});
 	}
 
 	override bool doProcessEvents(Duration timeout)
@@ -60,7 +61,7 @@ final class EpollEventLoop : PosixEventLoop {
 	}
 
 	override void dispose()
-	{
+	@nogc {
 		import core.sys.posix.unistd : close;
 		close(m_epoll);
 	}
@@ -74,13 +75,17 @@ final class EpollEventLoop : PosixEventLoop {
 		if (mask & EventMask.write) ev.events |= EPOLLOUT;
 		if (mask & EventMask.status) ev.events |= EPOLLERR|EPOLLHUP|EPOLLRDHUP;
 		ev.data.fd = cast(int)fd;
-		() @trusted { epoll_ctl(m_epoll, EPOLL_CTL_ADD, cast(int)fd, &ev); } ();
+		assumeSafeNoGC({
+			epoll_ctl(m_epoll, EPOLL_CTL_ADD, cast(int)fd, &ev);
+		});
 	}
 
 	override void unregisterFD(FD fd, EventMask mask)
 	{
 		debug (EventCoreEpollDebug) print("Epoll unregister FD %s", fd);
-		() @trusted { epoll_ctl(m_epoll, EPOLL_CTL_DEL, cast(int)fd, null); } ();
+		assumeSafeNoGC({
+			epoll_ctl(m_epoll, EPOLL_CTL_DEL, cast(int)fd, null);
+		});
 	}
 
 	override void updateFD(FD fd, EventMask old_mask, EventMask mask, bool edge_triggered = true)
@@ -93,7 +98,9 @@ final class EpollEventLoop : PosixEventLoop {
 		if (mask & EventMask.write) ev.events |= EPOLLOUT;
 		if (mask & EventMask.status) ev.events |= EPOLLERR|EPOLLHUP|EPOLLRDHUP;
 		ev.data.fd = cast(int)fd;
-		() @trusted { epoll_ctl(m_epoll, EPOLL_CTL_MOD, cast(int)fd, &ev); } ();
+		assumeSafeNoGC({
+			epoll_ctl(m_epoll, EPOLL_CTL_MOD, cast(int)fd, &ev);
+		});
 	}
 }
 
@@ -103,3 +110,8 @@ private timeval toTimeVal(Duration dur)
 	dur.split!("seconds", "usecs")(tvdur.tv_sec, tvdur.tv_usec);
 	return tvdur;
 }
+
+private void assumeSafeNoGC(scope void delegate() nothrow doit)
+@trusted {
+	(cast(void delegate() nothrow @nogc)doit)();
+}

source/eventcore/drivers/posix/events.d

@@ -4,7 +4,8 @@ module eventcore.drivers.posix.events;
 import eventcore.driver;
 import eventcore.drivers.posix.driver;
 import eventcore.internal.consumablequeue : ConsumableQueue;
-import eventcore.internal.utils : nogc_assert;
+import eventcore.internal.utils : nogc_assert, mallocT, freeT;
+
 
 version (linux) {
 	nothrow @nogc extern (C) int eventfd(uint initval, int flags);
@@ -25,21 +26,12 @@ final class PosixEventDriverEvents(Loop : PosixEventLoop, Sockets : EventDriverS
 		Loop m_loop;
 		Sockets m_sockets;
 		ubyte[ulong.sizeof] m_buf;
-		version (linux) {}
-		else {
-			// TODO: avoid the overhead of a mutex backed map here
-			import core.sync.mutex : Mutex;
-			Mutex m_eventsMutex;
-			EventID[DatagramSocketFD] m_events;
-		}
 	}
 
 	this(Loop loop, Sockets sockets)
-	{
+	@nogc {
 		m_loop = loop;
 		m_sockets = sockets;
-		version (linux) {}
-		else m_eventsMutex = new Mutex;
 	}
 
 	package @property Loop loop() { return m_loop; }
@@ -50,14 +42,14 @@ final class PosixEventDriverEvents(Loop : PosixEventLoop, Sockets : EventDriverS
 	}
 
 	package(eventcore) EventID createInternal(bool is_internal = true)
-	{
+	@nogc {
 		version (linux) {
 			auto eid = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
 			if (eid == -1) return EventID.invalid;
 			auto id = cast(EventID)eid;
 			// FIXME: avoid dynamic memory allocation for the queue
 			m_loop.initFD(id, FDFlags.internal,
-				EventSlot(new ConsumableQueue!EventCallback, false, is_internal));
+				EventSlot(mallocT!(ConsumableQueue!EventCallback), false, is_internal));
 			m_loop.registerFD(id, EventMask.read);
 			m_loop.setNotifyCallback!(EventType.read)(id, &onEvent);
 			releaseRef(id); // setNotifyCallback increments the reference count, but we need a value of 1 upon return
@@ -83,7 +75,7 @@ final class PosixEventDriverEvents(Loop : PosixEventLoop, Sockets : EventDriverS
 			} else {
 				// fake missing socketpair support on Windows
 				import std.socket : InternetAddress;
-				auto addr = new InternetAddress(0x7F000001, 0);
+				scope addr = new InternetAddress(0x7F000001, 0);
 				auto s = m_sockets.createDatagramSocketInternal(addr, null, true);
 				if (s == DatagramSocketFD.invalid) return EventID.invalid;
 				fd[0] = cast(sock_t)s;
@@ -106,18 +98,16 @@ final class PosixEventDriverEvents(Loop : PosixEventLoop, Sockets : EventDriverS
 				}
 			}
 
-			m_sockets.receive(s, m_buf, IOMode.once, &onSocketData);
+			m_sockets.receiveNoGC(s, m_buf, IOMode.once, &onSocketData);
 
 			// use the second socket as the event ID and as the sending end for
 			// other threads
 			auto id = cast(EventID)fd[1];
-			try {
+			try m_sockets.userData!EventID(s) = id;
-				synchronized (m_eventsMutex)
+			catch (Exception e) assert(false, e.msg);
-					m_events[s] = id;
-			} catch (Exception e) assert(false, e.msg);
 			// FIXME: avoid dynamic memory allocation for the queue
 			m_loop.initFD(id, FDFlags.internal,
-				EventSlot(new ConsumableQueue!EventCallback, false, is_internal, s));
+				EventSlot(mallocT!(ConsumableQueue!EventCallback), false, is_internal, s));
 			assert(getRC(id) == 1);
 			return id;
 		}
@@ -142,7 +132,7 @@ final class PosixEventDriverEvents(Loop : PosixEventLoop, Sockets : EventDriverS
 	}
 
 	final override void trigger(EventID event, bool notify_all)
-	shared @trusted {
+	shared @trusted @nogc {
 		import core.atomic : atomicStore;
 		auto thisus = cast(PosixEventDriverEvents)this;
 		assert(event < thisus.m_loop.m_fds.length, "Invalid event ID passed to shared triggerEvent.");
@@ -154,7 +144,7 @@ final class PosixEventDriverEvents(Loop : PosixEventLoop, Sockets : EventDriverS
 	}
 
 	final override void wait(EventID event, EventCallback on_event)
-	{
+	@nogc {
 		if (!isInternal(event)) m_loop.m_waiterCount++;
 		getSlot(event).waiters.put(on_event);
 	}
@@ -183,13 +173,12 @@ final class PosixEventDriverEvents(Loop : PosixEventLoop, Sockets : EventDriverS
 	version (linux) {}
 	else {
 		private void onSocketData(DatagramSocketFD s, IOStatus, size_t, scope RefAddress)
-		{
+		@nogc {
-			m_sockets.receive(s, m_buf, IOMode.once, &onSocketData);
+			m_sockets.receiveNoGC(s, m_buf, IOMode.once, &onSocketData);
-			EventID evt;
 			try {
-				synchronized (m_eventsMutex)
+				EventID evt = m_sockets.userData!EventID(s);
-					evt = m_events[s];
+				scope doit = { onEvent(evt); }; // cast to nogc
-				onEvent(evt);
+				() @trusted { (cast(void delegate() @nogc)doit)(); } ();
 			} catch (Exception e) assert(false, e.msg);
 		}
 	}
@@ -201,13 +190,13 @@ final class PosixEventDriverEvents(Loop : PosixEventLoop, Sockets : EventDriverS
 	}
 
 	final override bool releaseRef(EventID descriptor)
-	{
+	@nogc {
 		nogc_assert(getRC(descriptor) > 0, "Releasing reference to unreferenced event FD.");
 		if (--getRC(descriptor) == 0) {
 			if (!isInternal(descriptor))
 		 		m_loop.m_waiterCount -= getSlot(descriptor).waiters.length;
 			() @trusted nothrow {
-				try .destroy(getSlot(descriptor).waiters);
+				try freeT(getSlot(descriptor).waiters);
 				catch (Exception e) nogc_assert(false, e.msg);
 			} ();
 			version (linux) {
@@ -216,10 +205,6 @@ final class PosixEventDriverEvents(Loop : PosixEventLoop, Sockets : EventDriverS
 				auto rs = getSlot(descriptor).recvSocket;
 				m_sockets.cancelReceive(rs);
 				m_sockets.releaseRef(rs);
-				try {
-					synchronized (m_eventsMutex)
-						m_events.remove(rs);
-				} catch (Exception e) nogc_assert(false, e.msg);
 			}
 			m_loop.clearFD!EventSlot(descriptor);
 			version (Posix) close(cast(int)descriptor);
@@ -235,9 +220,9 @@ final class PosixEventDriverEvents(Loop : PosixEventLoop, Sockets : EventDriverS
 	}
 
 	private EventSlot* getSlot(EventID id)
-	{
+	@nogc {
 		nogc_assert(id < m_loop.m_fds.length, "Invalid event ID.");
-		return () @trusted { return &m_loop.m_fds[id].event(); } ();
+		return () @trusted @nogc { return &m_loop.m_fds[id].event(); } ();
 	}
 
 	private ref uint getRC(EventID id)
@@ -246,7 +231,7 @@ final class PosixEventDriverEvents(Loop : PosixEventLoop, Sockets : EventDriverS
 	}
 
 	private bool isInternal(EventID id)
-	{
+	@nogc {
 		return getSlot(id).isInternal;
 	}
 }

source/eventcore/drivers/posix/kqueue.d

@@ -34,14 +34,14 @@ alias KqueueEventDriver = PosixEventDriver!KqueueEventLoop;
 final class KqueueEventLoop : PosixEventLoop {
 	private {
 		int m_queue;
-		kevent_t[] m_changes;
+		size_t m_changeCount = 0;
-		kevent_t[] m_events;
+		kevent_t[100] m_changes;
+		kevent_t[100] m_events;
 	}
 
 	this()
-	@safe nothrow {
+	@safe nothrow @nogc {
 		m_queue = () @trusted { return kqueue(); } ();
-		m_events.length = 100;
 		assert(m_queue >= 0, "Failed to create kqueue.");
 	}
 
@@ -57,9 +57,8 @@ final class KqueueEventLoop : PosixEventLoop {
 		ts.tv_sec = cast(time_t)secs;
 		ts.tv_nsec = cast(uint)hnsecs * 100;
 
-		auto ret = kevent(m_queue, m_changes.ptr, cast(int)m_changes.length, m_events.ptr, cast(int)m_events.length, timeout == Duration.max ? null : &ts);
+		auto ret = kevent(m_queue, m_changes.ptr, cast(int)m_changeCount, m_events.ptr, cast(int)m_events.length, timeout == Duration.max ? null : &ts);
-		m_changes.length = 0;
+		m_changeCount = 0;
-		m_changes.assumeSafeAppend();
 
 		//print("kevent returned %s", ret);
 
@@ -97,11 +96,11 @@ final class KqueueEventLoop : PosixEventLoop {
 		if (edge_triggered) ev.flags |= EV_CLEAR;
 		if (mask & EventMask.read) {
 			ev.filter = EVFILT_READ;
-			m_changes ~= ev;
+			putChange(ev);
 		}
 		if (mask & EventMask.write) {
 			ev.filter = EVFILT_WRITE;
-			m_changes ~= ev;
+			putChange(ev);
 		}
 		//if (mask & EventMask.status) ev.events |= EPOLLERR|EPOLLRDHUP;
 	}
@@ -111,7 +110,7 @@ final class KqueueEventLoop : PosixEventLoop {
 		kevent_t ev;
 		ev.ident = fd;
 		ev.flags = EV_DELETE;
-		m_changes ~= ev;
+		putChange(ev);
 	}
 
 	override void updateFD(FD fd, EventMask old_mask, EventMask new_mask, bool edge_triggered = true)
@@ -124,16 +123,26 @@ final class KqueueEventLoop : PosixEventLoop {
 			ev.filter = EVFILT_READ;
 			ev.flags = new_mask & EventMask.read ? EV_ADD : EV_DELETE;
 			if (edge_triggered) ev.flags |= EV_CLEAR;
-			m_changes ~= ev;
+			putChange(ev);
 		}
 
 		if (changes & EventMask.write) {
 			ev.filter = EVFILT_WRITE;
 			ev.flags = new_mask & EventMask.write ? EV_ADD : EV_DELETE;
 			if (edge_triggered) ev.flags |= EV_CLEAR;
-			m_changes ~= ev;
+			putChange(ev);
 		}
 
 		//if (mask & EventMask.status) ev.events |= EPOLLERR|EPOLLRDHUP;
 	}
+
+	private void putChange(ref kevent_t ev)
+	@safe nothrow @nogc {
+		m_changes[m_changeCount++] = ev;
+		if (m_changeCount == m_changes.length) {
+			auto ret = (() @trusted => kevent(m_queue, &m_changes[0], cast(int)m_changes.length, null, 0, null)) ();
+			assert(ret == 0);
+			m_changeCount = 0;
+		}
+	}
 }

source/eventcore/drivers/posix/signals.d

@@ -17,7 +17,7 @@ final class SignalFDEventDriverSignals(Loop : PosixEventLoop) : EventDriverSigna
 
 	private Loop m_loop;
 
-	this(Loop loop) { m_loop = loop; }
+	this(Loop loop) @nogc { m_loop = loop; }
 
 	override SignalListenID listen(int sig, SignalCallback on_signal)
 	{

source/eventcore/drivers/posix/sockets.d

@@ -654,7 +654,7 @@ final class PosixEventDriverSockets(Loop : PosixEventLoop) : EventDriverSockets
 	}
 
 	package DatagramSocketFD adoptDatagramSocketInternal(int socket, bool is_internal = true, bool close_on_exec = false)
-	{
+	@nogc {
 		auto fd = DatagramSocketFD(socket);
 		if (m_loop.m_fds[fd].common.refCount) // FD already in use?
 			return DatagramSocketFD.init;
@@ -742,8 +742,16 @@ final class PosixEventDriverSockets(Loop : PosixEventLoop) : EventDriverSockets
 		on_receive_finish(socket, IOStatus.ok, ret, src_addrc);
 	}
 
+	package void receiveNoGC(DatagramSocketFD socket, ubyte[] buffer, IOMode mode, void delegate(DatagramSocketFD, IOStatus, size_t, scope RefAddress) @safe nothrow @nogc on_receive_finish)
+	@trusted @nogc {
+		scope void delegate() @safe nothrow do_it = {
+			receive(socket, buffer, mode, on_receive_finish);
+		};
+		(cast(void delegate() @safe nothrow @nogc)do_it)();
+	}
+
 	void cancelReceive(DatagramSocketFD socket)
-	{
+	@nogc {
 		assert(m_loop.m_fds[socket].datagramSocket.readCallback !is null, "Cancelling read when there is no read in progress.");
 		m_loop.setNotifyCallback!(EventType.read)(socket, null);
 		m_loop.m_fds[socket].datagramSocket.readBuffer = null;
@@ -855,7 +863,7 @@ final class PosixEventDriverSockets(Loop : PosixEventLoop) : EventDriverSockets
 	}
 
 	final override bool releaseRef(SocketFD fd)
-	{
+	@nogc {
 		import taggedalgebraic : hasType;
 		auto slot = () @trusted { return &m_loop.m_fds[fd]; } ();
 		nogc_assert(slot.common.refCount > 0, "Releasing reference to unreferenced socket FD.");

source/eventcore/drivers/posix/watchers.d

@@ -3,7 +3,7 @@ module eventcore.drivers.posix.watchers;
 
 import eventcore.driver;
 import eventcore.drivers.posix.driver;
-import eventcore.internal.utils : nogc_assert;
+import eventcore.internal.utils : mallocT, freeT, nogc_assert;
 
 
 final class InotifyEventDriverWatchers(Events : EventDriverEvents) : EventDriverWatchers
@@ -245,7 +245,7 @@ final class PollEventDriverWatchers(Events : EventDriverEvents) : EventDriverWat
 	}
 
 	this(Events events)
-	{
+	@nogc {
 		m_events = events;
 	}
 
@@ -313,42 +313,40 @@ final class PollEventDriverWatchers(Events : EventDriverEvents) : EventDriverWat
 
 	private void onEvent(EventID evt)
 	{
-		import std.algorithm.mutation : swap;
-
 		auto pt = evt in m_pollers;
 		if (!pt) return;
 
 		m_events.wait(evt, &onEvent);
 
-		FileChange[] changes;
+		foreach (ref ch; pt.readChanges())
-		try synchronized (pt.m_changesMutex)
-			swap(changes, pt.m_changes);
-		catch (Exception e) assert(false, "Failed to acquire mutex: "~e.msg);
-
-		foreach (ref ch; changes)
 			pt.m_callback(cast(WatcherID)evt, ch);
 	}
 
 
 	private final class PollingThread : Thread {
-		int refCount = 1;
-		EventID changesEvent;
-
 		private {
 			shared(Events) m_eventsDriver;
 			Mutex m_changesMutex;
-			/*shared*/ FileChange[] m_changes;
+			/*shared*/ FileChange[] m_changes; // protected by m_changesMutex
+			EventID m_changesEvent; // protected by m_changesMutex
 			immutable string m_basePath;
 			immutable bool m_recursive;
 			immutable FileChangesCallback m_callback;
-			size_t m_entryCount;
 
-			struct Entry {
+			final static class Entry {
-				Entry* parent;
+				Entry parent;
 				string name;
 				ulong size;
 				long lastChange;
 
+				this(Entry parent, string name, ulong size, long lastChange)
+				{
+					this.parent = parent;
+					this.name = name;
+					this.size = size;
+					this.lastChange = lastChange;
+				}
+
 				string path()
 				{
 					import std.path : buildPath;
@@ -361,11 +359,13 @@ final class PollEventDriverWatchers(Events : EventDriverEvents) : EventDriverWat
 			}
 
 			struct Key {
-				Entry* parent;
+				Entry parent;
 				string name;
 			}
 
-			Entry*[Key] m_entries;
+			// used only within the polling thread
+			Entry[Key] m_entries;
+			size_t m_entryCount;
 		}
 
 		this(shared(Events) event_driver, EventID event, string path, bool recursive, FileChangesCallback callback)
@@ -374,7 +374,7 @@ final class PollEventDriverWatchers(Events : EventDriverEvents) : EventDriverWat
 
 			m_changesMutex = new Mutex;
 			m_eventsDriver = event_driver;
-			changesEvent = event;
+			m_changesEvent = event;
 			m_basePath = path;
 			m_recursive = recursive;
 			m_callback = callback;
@@ -387,10 +387,21 @@ final class PollEventDriverWatchers(Events : EventDriverEvents) : EventDriverWat
 		void dispose()
 		nothrow {
 			try synchronized (m_changesMutex) {
-				changesEvent = EventID.invalid;
+				m_changesEvent = EventID.invalid;
 			} catch (Exception e) assert(false, e.msg);
 		}
 
+		FileChange[] readChanges()
+		nothrow {
+			import std.algorithm.mutation : swap;
+
+			FileChange[] changes;
+			try synchronized (m_changesMutex)
+				swap(changes, m_changes);
+			catch (Exception e) assert(false, "Failed to acquire mutex: "~e.msg);
+			return changes;
+		}
+
 		private void run()
 		nothrow @trusted {
 			import core.time : msecs;
@@ -401,7 +412,7 @@ final class PollEventDriverWatchers(Events : EventDriverEvents) : EventDriverWat
 				auto timeout = Clock.currTime(UTC()) + min(m_entryCount, 60000).msecs + 1000.msecs;
 				while (true) {
 					try synchronized (m_changesMutex) {
-						if (changesEvent == EventID.invalid) return;
+						if (m_changesEvent == EventID.invalid) return;
 					} catch (Exception e) assert(false, "Mutex lock failed: "~e.msg);
 					auto remaining = timeout - Clock.currTime(UTC());
 					if (remaining <= 0.msecs) break;
@@ -411,9 +422,9 @@ final class PollEventDriverWatchers(Events : EventDriverEvents) : EventDriverWat
 				scan(true);
 
 				try synchronized (m_changesMutex) {
-					if (changesEvent == EventID.invalid) return;
+					if (m_changesEvent == EventID.invalid) return;
 					if (m_changes.length)
-						m_eventsDriver.trigger(changesEvent, false);
+						m_eventsDriver.trigger(m_changesEvent, false);
 				} catch (Exception e) assert(false, "Mutex lock failed: "~e.msg);
 			} catch (Throwable th) {
 				import core.stdc.stdio : fprintf, stderr;
@@ -435,8 +446,8 @@ final class PollEventDriverWatchers(Events : EventDriverEvents) : EventDriverWat
 		@trusted nothrow {
 			import std.algorithm.mutation : swap;
 
-			Entry*[Key] new_entries;
+			Entry[Key] new_entries;
-			Entry*[] added;
+			Entry[] added;
 			size_t ec = 0;
 
 			scan(null, generate_changes, new_entries, added, ec);
@@ -445,12 +456,9 @@ final class PollEventDriverWatchers(Events : EventDriverEvents) : EventDriverWat
 				if (!e.key.parent || Key(e.key.parent.parent, e.key.parent.name) !in m_entries) {
 					if (generate_changes)
 						addChange(FileChangeKind.removed, e.key, e.value.isDir);
+					try freeT(e.value);
+					catch (Exception e) assert(false, e.msg);
 				}
-
-				static if (__VERSION__ >= 2079) {
-					import core.memory : __delete;
-					__delete(e.value);
-				} else mixin("delete e.value;");
 			}
 
 			foreach (e; added)
@@ -460,7 +468,7 @@ final class PollEventDriverWatchers(Events : EventDriverEvents) : EventDriverWat
 			m_entryCount = ec;
 		}
 
-		private void scan(Entry* parent, bool generate_changes, ref Entry*[Key] new_entries, ref Entry*[] added, ref size_t ec)
+		private void scan(Entry parent, bool generate_changes, ref Entry[Key] new_entries, ref Entry[] added, ref size_t ec)
 		@trusted nothrow {
 			import std.file : SpanMode, dirEntries;
 			import std.path : buildPath, baseName;
@@ -486,7 +494,7 @@ final class PollEventDriverWatchers(Events : EventDriverEvents) : EventDriverWat
 					ec++;
 					m_entries.remove(key);
 				} else {
-					auto e = new Entry(parent, key.name, de.isDir ? ulong.max : de.size, modified_time);
+					auto e = mallocT!Entry(parent, key.name, de.isDir ? ulong.max : de.size, modified_time);
 					new_entries[key] = e;
 					ec++;
 					if (generate_changes) added ~= e;

source/eventcore/drivers/threadedfile.d

@@ -421,10 +421,10 @@ private struct StaticTaskPool {
 
 		if (!m_refCount++) {
 			try {
-				m_pool = new TaskPool(4);
+				m_pool = mallocT!TaskPool(4);
 				m_pool.isDaemon = true;
 			} catch (Exception e) {
-				assert(false, "Failed to create file thread pool: "~e.msg);
+				assert(false, e.msg);
 			}
 		}
 
@@ -447,8 +447,10 @@ private struct StaticTaskPool {
 
 		if (fin_pool) {
 			log("finishing thread pool");
-			try fin_pool.finish();
+			try {
-			catch (Exception e) {
+				fin_pool.finish(true);
+				freeT(fin_pool);
+			} catch (Exception e) {
 				//log("Failed to shut down file I/O thread pool.");
 			}
 		}

source/eventcore/drivers/timer.d

@@ -4,8 +4,9 @@
 module eventcore.drivers.timer;
 
 import eventcore.driver;
+import eventcore.internal.consumablequeue;
 import eventcore.internal.dlist;
-import eventcore.internal.utils : nogc_assert;
+import eventcore.internal.utils : mallocT, freeT, nogc_assert;
 
 
 final class LoopTimeoutTimerDriver : EventDriverTimers {
@@ -24,7 +25,7 @@ final class LoopTimeoutTimerDriver : EventDriverTimers {
 		TimerSlot*[TimerID] m_timers;
 		StackDList!TimerSlot m_timerQueue;
 		TimerID m_lastTimerID;
-		TimerSlot*[] m_firedTimers;
+		ConsumableQueue!(TimerSlot*) m_firedTimers;
 	}
 
 	static this()
@@ -32,6 +33,17 @@ final class LoopTimeoutTimerDriver : EventDriverTimers {
 		ms_allocator.parent = Mallocator.instance;
 	}
 
+	this()
+	@nogc @safe nothrow {
+		m_firedTimers = mallocT!(ConsumableQueue!(TimerSlot*));
+	}
+
+	~this()
+	@nogc @trusted nothrow {
+		try freeT(m_firedTimers);
+		catch (Exception e) assert(false, e.msg);
+	}
+
 	package @property size_t pendingCount() const @safe nothrow { return m_timerQueue.length; }
 
 	final package Duration getNextTimeout(long stdtime)
@@ -53,27 +65,24 @@ final class LoopTimeoutTimerDriver : EventDriverTimers {
 				do tm.timeout += tm.repeatDuration;
 				while (tm.timeout <= stdtime);
 			} else tm.pending = false;
-			m_firedTimers ~= tm;
+			m_firedTimers.put(tm);
 		}
 
-		foreach (tm; m_firedTimers) {
+		auto processed_timers = m_firedTimers.consume();
+
+		foreach (tm; processed_timers) {
 			m_timerQueue.remove(tm);
 			if (tm.repeatDuration > 0)
 				enqueueTimer(tm);
 		}
 
-		foreach (tm; m_firedTimers) {
+		foreach (tm; processed_timers) {
 			auto cb = tm.callback;
 			tm.callback = null;
 			if (cb) cb(tm.id);
 		}
 
-		bool any_fired = m_firedTimers.length > 0;
+		return processed_timers.length > 0;
-
-		m_firedTimers.length = 0;
-		m_firedTimers.assumeSafeAppend();
-
-		return any_fired;
 	}
 
 	final override TimerID create()

source/eventcore/drivers/winapi/core.d

@@ -5,7 +5,7 @@ version (Windows):
 import eventcore.driver;
 import eventcore.drivers.timer;
 import eventcore.internal.consumablequeue;
-import eventcore.internal.utils : nogc_assert;
+import eventcore.internal.utils : mallocT, freeT, nogc_assert;
 import eventcore.internal.win32;
 import core.sync.mutex : Mutex;
 import core.time : Duration;
@@ -21,8 +21,9 @@ final class WinAPIEventDriverCore : EventDriverCore {
 		size_t m_waiterCount;
 		DWORD m_tid;
 		LoopTimeoutTimerDriver m_timers;
-		HANDLE[] m_registeredEvents;
+		HANDLE[MAXIMUM_WAIT_OBJECTS] m_registeredEvents;
-		void delegate() @safe nothrow[HANDLE] m_eventCallbacks;
+		void delegate() @safe nothrow[MAXIMUM_WAIT_OBJECTS] m_registeredEventCallbacks;
+		DWORD m_registeredEventCount = 0;
 		HANDLE m_fileCompletionEvent;
 		ConsumableQueue!IOEvent m_ioEvents;
 
@@ -35,27 +36,36 @@ final class WinAPIEventDriverCore : EventDriverCore {
 	}
 
 	this(LoopTimeoutTimerDriver timers)
-	{
+	@nogc {
 		m_timers = timers;
 		m_tid = () @trusted { return GetCurrentThreadId(); } ();
 		m_fileCompletionEvent = () @trusted { return CreateEventW(null, false, false, null); } ();
 		registerEvent(m_fileCompletionEvent);
-		m_ioEvents = new ConsumableQueue!IOEvent;
+		m_ioEvents = mallocT!(ConsumableQueue!IOEvent);
 
 		static if (__VERSION__ >= 2074)
-			m_threadCallbackMutex = new shared Mutex;
+			m_threadCallbackMutex = mallocT!(shared(Mutex));
 		else {
-			() @trusted { m_threadCallbackMutex = cast(shared)new Mutex; } ();
+			() @trusted { m_threadCallbackMutex = cast(shared)mallocT!Mutex; } ();
 		}
-		m_threadCallbacks = new ConsumableQueue!(Tuple!(ThreadCallback, intptr_t));
+		m_threadCallbacks = mallocT!(ConsumableQueue!(Tuple!(ThreadCallback, intptr_t)));
 		m_threadCallbacks.reserve(1000);
 	}
 
+	void dispose()
+	@trusted {
+		try {
+			freeT(m_threadCallbacks);
+			freeT(m_threadCallbackMutex);
+			freeT(m_ioEvents);
+		} catch (Exception e) assert(false, e.msg);
+	}
+
 	override size_t waiterCount() { return m_waiterCount + m_timers.pendingCount; }
 
-	package void addWaiter() { m_waiterCount++; }
+	package void addWaiter() @nogc { m_waiterCount++; }
 	package void removeWaiter()
-	{
+	@nogc {
 		assert(m_waiterCount > 0, "Decrementing waiter count below zero.");
 		m_waiterCount--;
 	}
@@ -159,7 +169,7 @@ final class WinAPIEventDriverCore : EventDriverCore {
 		bool got_event;
 
 		DWORD timeout_msecs = max_wait == Duration.max ? INFINITE : cast(DWORD)min(max(max_wait.total!"msecs", 0), DWORD.max);
-		auto ret = () @trusted { return MsgWaitForMultipleObjectsEx(cast(DWORD)m_registeredEvents.length, m_registeredEvents.ptr,
+		auto ret = () @trusted { return MsgWaitForMultipleObjectsEx(m_registeredEventCount, m_registeredEvents.ptr,
 			timeout_msecs, QS_ALLEVENTS, MWMO_ALERTABLE|MWMO_INPUTAVAILABLE); } ();
 
 		while (!m_ioEvents.empty) {
@@ -168,9 +178,9 @@ final class WinAPIEventDriverCore : EventDriverCore {
 		}
 
 		if (ret == WAIT_IO_COMPLETION) got_event = true;
-		else if (ret >= WAIT_OBJECT_0 && ret < WAIT_OBJECT_0 + m_registeredEvents.length) {
+		else if (ret >= WAIT_OBJECT_0 && ret < WAIT_OBJECT_0 + m_registeredEventCount) {
-			if (auto pc = m_registeredEvents[ret - WAIT_OBJECT_0] in m_eventCallbacks) {
+			if (auto cb = m_registeredEventCallbacks[ret - WAIT_OBJECT_0]) {
-				(*pc)();
+				cb();
 				got_event = true;
 			}
 		}
@@ -209,9 +219,11 @@ final class WinAPIEventDriverCore : EventDriverCore {
 
 
 	package void registerEvent(HANDLE event, void delegate() @safe nothrow callback = null)
-	{
+	@nogc {
-		m_registeredEvents ~= event;
+		assert(m_registeredEventCount < MAXIMUM_WAIT_OBJECTS, "Too many registered events.");
-		if (callback) m_eventCallbacks[event] = callback;
+		m_registeredEvents[m_registeredEventCount] = event;
+		if (callback) m_registeredEventCallbacks[m_registeredEventCount] = callback;
+		m_registeredEventCount++;
 	}
 
 	package SlotType* setupSlot(SlotType)(HANDLE h)
@@ -231,7 +243,7 @@ final class WinAPIEventDriverCore : EventDriverCore {
 	}
 
 	package void discardEvents(scope OVERLAPPED_CORE*[] overlapped...)
-	{
+@nogc	{
 		import std.algorithm.searching : canFind;
 		m_ioEvents.filterPending!(evt => !overlapped.canFind(evt.overlapped));
 	}

source/eventcore/drivers/winapi/driver.d

@@ -18,6 +18,7 @@ import eventcore.drivers.winapi.files;
 import eventcore.drivers.winapi.signals;
 import eventcore.drivers.winapi.sockets;
 import eventcore.drivers.winapi.watchers;
+import eventcore.internal.utils : mallocT, freeT;
 import core.sys.windows.windows;
 
 static assert(HANDLE.sizeof <= FD.BaseType.sizeof);
@@ -39,23 +40,25 @@ final class WinAPIEventDriver : EventDriver {
 	static WinAPIEventDriver threadInstance;
 
 	this()
-	@safe {
+	@safe nothrow @nogc {
 		assert(threadInstance is null);
 		threadInstance = this;
 
 		import std.exception : enforce;
 
 		WSADATA wd;
-		enforce(() @trusted { return WSAStartup(0x0202, &wd); } () == 0, "Failed to initialize WinSock");
 
-		m_signals = new WinAPIEventDriverSignals();
+		auto res = () @trusted { return WSAStartup(0x0202, &wd); } ();
-		m_timers = new LoopTimeoutTimerDriver();
+		assert(res == 0, "Failed to initialize WinSock");
-		m_core = new WinAPIEventDriverCore(m_timers);
+
-		m_events = new WinAPIEventDriverEvents(m_core);
+		m_signals = mallocT!WinAPIEventDriverSignals();
-		m_files = new WinAPIEventDriverFiles(m_core);
+		m_timers = mallocT!LoopTimeoutTimerDriver();
-		m_sockets = new WinAPIEventDriverSockets(m_core);
+		m_core = mallocT!WinAPIEventDriverCore(m_timers);
-		m_dns = new WinAPIEventDriverDNS();
+		m_events = mallocT!WinAPIEventDriverEvents(m_core);
-		m_watchers = new WinAPIEventDriverWatchers(m_core);
+		m_files = mallocT!WinAPIEventDriverFiles(m_core);
+		m_sockets = mallocT!WinAPIEventDriverSockets(m_core);
+		m_dns = mallocT!WinAPIEventDriverDNS();
+		m_watchers = mallocT!WinAPIEventDriverWatchers(m_core);
 	}
 
 @safe: /*@nogc:*/ nothrow:
@@ -75,8 +78,20 @@ final class WinAPIEventDriver : EventDriver {
 	{
 		if (!m_events) return;
 		m_events.dispose();
-		m_events = null;
+		m_core.dispose();
 		assert(threadInstance !is null);
 		threadInstance = null;
+
+		try () @trusted {
+			freeT(m_watchers);
+			freeT(m_dns);
+			freeT(m_sockets);
+			freeT(m_files);
+			freeT(m_events);
+			freeT(m_core);
+			freeT(m_timers);
+			freeT(m_signals);
+		} ();
+		catch (Exception e) assert(false, e.msg);
 	}
 }

source/eventcore/drivers/winapi/events.d

@@ -6,7 +6,7 @@ import eventcore.driver;
 import eventcore.drivers.winapi.core;
 import eventcore.internal.win32;
 import eventcore.internal.consumablequeue;
-import eventcore.internal.utils : nogc_assert;
+import eventcore.internal.utils : mallocT, freeT, nogc_assert;
 
 
 final class WinAPIEventDriverEvents : EventDriverEvents {
@@ -31,10 +31,10 @@ final class WinAPIEventDriverEvents : EventDriverEvents {
 	}
 
 	this(WinAPIEventDriverCore core)
-	{
+	@nogc {
 		m_core = core;
 		m_event = () @trusted { return CreateEvent(null, false, false, null); } ();
-		m_pending = new ConsumableQueue!Trigger; // FIXME: avoid GC allocation
+		m_pending = mallocT!(ConsumableQueue!Trigger); // FIXME: avoid GC allocation
 		InitializeCriticalSection(&m_mutex);
 		m_core.registerEvent(m_event, &triggerPending);
 	}
@@ -42,7 +42,7 @@ final class WinAPIEventDriverEvents : EventDriverEvents {
 	void dispose()
 	@trusted {
 		scope (failure) assert(false);
-		destroy(m_pending);
+		freeT(m_pending);
 	}
 
 	override EventID create()

source/eventcore/drivers/winapi/files.d

@@ -17,7 +17,7 @@ final class WinAPIEventDriverFiles : EventDriverFiles {
 	}
 
 	this(WinAPIEventDriverCore core)
-	{
+	@nogc {
 		m_core = core;
 	}
 

source/eventcore/drivers/winapi/sockets.d

@@ -25,7 +25,7 @@ final class WinAPIEventDriverSockets : EventDriverSockets {
 	}
 
 	this(WinAPIEventDriverCore core)
-	@trusted {
+	@trusted @nogc {
 		m_tid = GetCurrentThreadId();
 		m_core = core;
 
@@ -406,7 +406,7 @@ final class WinAPIEventDriverSockets : EventDriverSockets {
 	}
 
 	override void cancelRead(StreamSocketFD socket)
-	@trusted {
+	@trusted @nogc {
 		if (!m_sockets[socket].streamSocket.read.callback) return;
 		CancelIoEx(cast(HANDLE)cast(SOCKET)socket, cast(LPOVERLAPPED)&m_sockets[socket].streamSocket.read.overlapped);
 		m_sockets[socket].streamSocket.read.callback = null;
@@ -414,7 +414,7 @@ final class WinAPIEventDriverSockets : EventDriverSockets {
 	}
 
 	override void cancelWrite(StreamSocketFD socket)
-	@trusted {
+	@trusted @nogc {
 		if (!m_sockets[socket].streamSocket.write.callback) return;
 		CancelIoEx(cast(HANDLE)cast(SOCKET)socket, cast(LPOVERLAPPED)&m_sockets[socket].streamSocket.write.overlapped);
 		m_sockets[socket].streamSocket.write.callback = null;
@@ -549,7 +549,7 @@ final class WinAPIEventDriverSockets : EventDriverSockets {
 	}
 
 	override void cancelReceive(DatagramSocketFD socket)
-	@trusted {
+	@trusted @nogc {
 		if (!m_sockets[socket].datagramSocket.read.callback) return;
 		CancelIoEx(cast(HANDLE)cast(SOCKET)socket, cast(LPOVERLAPPED)&m_sockets[socket].datagramSocket.read.overlapped);
 		m_sockets[socket].datagramSocket.read.callback = null;
@@ -643,7 +643,7 @@ final class WinAPIEventDriverSockets : EventDriverSockets {
 	}
 
 	override void cancelSend(DatagramSocketFD socket)
-	@trusted {
+	@trusted @nogc {
 		if (!m_sockets[socket].datagramSocket.write.callback) return;
 		CancelIoEx(cast(HANDLE)cast(SOCKET)socket, cast(LPOVERLAPPED)&m_sockets[socket].datagramSocket.write.overlapped);
 		m_sockets[socket].datagramSocket.write.callback = null;
@@ -719,7 +719,7 @@ final class WinAPIEventDriverSockets : EventDriverSockets {
 	}
 
 	override bool releaseRef(SocketFD fd)
-	{
+	@nogc {
 		import taggedalgebraic : hasType;
 		auto slot = () @trusted { return &m_sockets[fd]; } ();
 		nogc_assert(slot.common.refCount > 0, "Releasing reference to unreferenced socket FD.");
@@ -787,7 +787,7 @@ final class WinAPIEventDriverSockets : EventDriverSockets {
 	}
 
 	private void* rawUserDataImpl(FD descriptor, size_t size, DataInitializer initialize, DataInitializer destroy)
-	@system {
+	@system @nogc {
 		SocketSlot* fds = &m_sockets[descriptor].common;
 		assert(fds.userDataDestructor is null || fds.userDataDestructor is destroy,
 			"Requesting user data with differing type (destructor).");
@@ -808,7 +808,7 @@ final class WinAPIEventDriverSockets : EventDriverSockets {
 	}
 
 	package void clearSocketSlot(FD fd)
-	{
+	@nogc {
 		auto slot = () @trusted { return &m_sockets[fd]; } ();
 		if (slot.common.userDataDestructor)
 			() @trusted { slot.common.userDataDestructor(slot.common.userData.ptr); } ();
@@ -889,8 +889,8 @@ final class WinAPIEventDriverSockets : EventDriverSockets {
 	}
 }
 
-void setupWindowClass() nothrow
+void setupWindowClass()
-@trusted {
+@trusted nothrow @nogc {
 	static __gshared registered = false;
 
 	if (registered) return;

source/eventcore/drivers/winapi/watchers.d

@@ -16,7 +16,7 @@ final class WinAPIEventDriverWatchers : EventDriverWatchers {
 	}
 
 	this(WinAPIEventDriverCore core)
-	{
+	@nogc {
 		m_core = core;
 	}
 

source/eventcore/internal/consumablequeue.d

@@ -1,5 +1,8 @@
 module eventcore.internal.consumablequeue;
 
+import eventcore.internal.utils : mallocNT, freeNT;
+
+
 /** FIFO queue with support for chunk-wise consumption.
 */
 final class ConsumableQueue(T)
@@ -18,6 +21,12 @@ final class ConsumableQueue(T)
 		size_t m_pendingCount;
 	}
 
+	~this()
+	@trusted @nogc nothrow {
+		if (m_storage !is null)
+			freeNT(m_storage);
+	}
+
 	@property size_t length() const { return m_pendingCount; }
 
 	@property bool empty() const { return length == 0; }
@@ -43,11 +52,15 @@ final class ConsumableQueue(T)
 		while (new_capacity < min_capacity) new_capacity *= 2;
 		auto new_capacity_mask = new_capacity - 1;
 
-		auto new_storage = new Slot[new_capacity];
+		auto new_storage = mallocNT!Slot(new_capacity);
 		foreach (i; 0 .. m_consumedCount + m_pendingCount)
 			new_storage[(m_first + i) & new_capacity_mask] = m_storage[(m_first + i) & m_capacityMask];
 
-		m_storage = new_storage;
+		() @trusted {
+			if (m_storage !is null)
+				freeNT(m_storage);
+			m_storage = new_storage;
+		} ();
 		m_capacityMask = new_capacity_mask;
 	}
 

source/eventcore/internal/utils.d

@@ -1,5 +1,7 @@
 module eventcore.internal.utils;
 
+import core.memory : GC;
+import std.traits : hasIndirections;
 import taggedalgebraic;
 
 
@@ -8,17 +10,83 @@ void print(ARGS...)(string str, ARGS args)
 	import std.format : formattedWrite;
 	StdoutRange r;
 	scope cb = () {
-		scope (failure) assert(false);
+		try (&r).formattedWrite(str, args);
-		(&r).formattedWrite(str, args);
+		catch (Exception e) assert(false, e.msg);
 	};
 	(cast(void delegate() @nogc @safe nothrow)cb)();
 	r.put('\n');
 }
 
+T mallocT(T, ARGS...)(ARGS args)
+@trusted @nogc {
+	import core.stdc.stdlib : malloc;
+	import std.conv : emplace;
+
+	enum size = __traits(classInstanceSize, T);
+	auto ret = cast(T)malloc(size);
+	static if (hasIndirections!T)
+		GC.addRange(cast(void*)ret, __traits(classInstanceSize, T));
+	scope doit = { emplace!T((cast(void*)ret)[0 .. size], args); };
+	static if (__traits(compiles, () nothrow { typeof(doit).init(); })) // NOTE: doing the typeof thing here, because LDC 1.7.0 otherwise thinks doit gets escaped here
+		(cast(void delegate() @nogc nothrow)doit)();
+	else
+		(cast(void delegate() @nogc)doit)();
+	return ret;
+}
+
+void freeT(T)(ref T inst) @nogc
+	if (is(T == class))
+{
+	import core.stdc.stdlib : free;
+
+	if (!inst) return;
+
+	noGCDestroy(inst);
+	static if (hasIndirections!T)
+		GC.removeRange(cast(void*)inst);
+	free(cast(void*)inst);
+	inst = null;
+}
+
+T[] mallocNT(T)(size_t cnt)
+@trusted {
+	import core.stdc.stdlib : malloc;
+	import std.conv : emplace;
+
+	auto ret = (cast(T*)malloc(T.sizeof * cnt))[0 .. cnt];
+	static if (hasIndirections!T)
+		GC.addRange(cast(void*)ret, T.sizeof * cnt);
+	foreach (ref v; ret)
+		static if (!is(T == class))
+			emplace!T(&v);
+		else v = null;
+	return ret;
+}
+
+void freeNT(T)(ref T[] arr)
+{
+	import core.stdc.stdlib : free;
+
+	foreach (ref v; arr)
+		static if (!is(T == class))
+			destroy(v);
+	static if (hasIndirections!T)
+		GC.removeRange(arr.ptr);
+	free(arr.ptr);
+	arr = null;
+}
+
+private void noGCDestroy(T)(ref T t)
+@trusted {
+	// FIXME: only do this if the destructor chain is actually nogc
+	scope doit = { destroy(t); };
+	(cast(void delegate() @nogc)doit)();
+}
+
 private extern(C) Throwable.TraceInfo _d_traceContext(void* ptr = null);
 
 void nogc_assert(bool cond, string message, string file = __FILE__, int line = __LINE__)
-@trusted nothrow {
+@trusted nothrow @nogc {
 	import core.stdc.stdlib : abort;
 	import std.stdio : stderr;
 
@@ -28,12 +96,15 @@ void nogc_assert(bool cond, string message, string file = __FILE__, int line = _
 			assert(false);
 		}
 
-		stderr.writefln("Assertion failure @%s(%s): %s", file, line, message);
+		scope doit = {
-		stderr.writeln("------------------------");
+			stderr.writefln("Assertion failure @%s(%s): %s", file, line, message);
-		if (auto info = _d_traceContext(null)) {
+			stderr.writeln("------------------------");
-			foreach (s; info)
+			if (auto info = _d_traceContext(null)) {
-				stderr.writeln(s);
+				foreach (s; info)
-		} else stderr.writeln("no stack trace available");
+					stderr.writeln(s);
+			} else stderr.writeln("no stack trace available");
+		};
+		(cast(void delegate() @nogc)doit)(); // write and _d_traceContext are not nogc
 	}
 }
 
@@ -53,14 +124,11 @@ struct StdoutRange {
 }
 
 struct ChoppedVector(T, size_t CHUNK_SIZE = 16*64*1024/nextPOT(T.sizeof)) {
-	import core.memory : GC;
-
 	static assert(nextPOT(CHUNK_SIZE) == CHUNK_SIZE,
 		"CHUNK_SIZE must be a power of two for performance reasons.");
 
 	@safe: nothrow:
 	import core.stdc.stdlib : calloc, free, malloc, realloc;
-	import std.traits : hasIndirections;
 
 	alias chunkSize = CHUNK_SIZE;
 
@@ -85,12 +153,13 @@ struct ChoppedVector(T, size_t CHUNK_SIZE = 16*64*1024/nextPOT(T.sizeof)) {
 	@nogc {
 		() @trusted {
 			foreach (i; 0 .. m_chunkCount) {
-				destroy(m_chunks[i]);
+				destroy(*m_chunks[i]);
 				static if (hasIndirections!T)
 					GC.removeRange(m_chunks[i]);
 				free(m_chunks[i]);
 			}
 			free(m_chunks.ptr);
+			m_chunks = null;
 		} ();
 		m_chunkCount = 0;
 		m_length = 0;
@@ -183,7 +252,7 @@ struct AlgebraicChoppedVector(TCommon, TSpecific...)
 		import std.format : format;
 		string ret;
 		foreach (i, U; TSpecific)
-			ret ~= "@property ref TSpecific[%s] %s() nothrow @safe { return this.specific.get!(TSpecific[%s]); }\n"
+			ret ~= "@property ref TSpecific[%s] %s() nothrow @safe @nogc { return this.specific.get!(TSpecific[%s]); }\n"
 				.format(i, U.Handle.name, i);
 		return ret;
 	}
@@ -207,10 +276,13 @@ struct SmallIntegerSet(V : size_t)
 		size_t m_count;
 	}
 
+	@disable this(this);
+
 	@property bool empty() const { return m_count == 0; }
 
 	void insert(V i)
 	{
+		assert(i >= 0);
 		foreach (j; 0 .. m_bits.length) {
 			uint b = 1u << (i%32);
 			i /= 32;
@@ -223,6 +295,9 @@ struct SmallIntegerSet(V : size_t)
 
 	void remove(V i)
 	{
+		assert(i >= 0);
+		if (i >= m_bits[0].length * 32) return;
+
 		foreach (j; 0 .. m_bits.length) {
 			uint b = 1u << (i%32);
 			i /= 32;