module libasync.posix;

version (Posix):

import libasync.types;
import std.string : toStringz;
import std.conv : to;
import std.datetime : Duration, msecs, seconds, SysTime;
import std.traits : isIntegral;
import std.typecons : Tuple, tuple;
import std.container : Array;

import core.stdc.errno;
import libasync.events;
import libasync.internals.memory : FreeListObjectAlloc;
import libasync.internals.hashmap;
import libasync.internals.path;
import core.sys.posix.signal;
import libasync.posix2;
import core.sync.mutex;
enum SOCKET_ERROR = -1;
alias fd_t = int;


version(linux) {
	import libasync.internals.epoll;
	const EPOLL = true;
	extern(C) nothrow @nogc {
		int __libc_current_sigrtmin();
		int __libc_current_sigrtmax();
	}
	bool g_signalsBlocked;
	package nothrow void blockSignals() {
		try {
			/// Block signals to reserve SIGRTMIN .. " +30 for AsyncSignal
			sigset_t mask;
			// todo: use more signals for more event loops per thread.. (is this necessary?)
			//foreach (j; __libc_current_sigrtmin() .. __libc_current_sigrtmax() + 1) {
				//import std.stdio : writeln; 
				//try writeln("Blocked signal " ~ (__libc_current_sigrtmin() + j).to!string ~ " in instance " ~ m_instanceId.to!string); catch {}
			sigemptyset(&mask);
			sigaddset(&mask, cast(int) __libc_current_sigrtmin());
			pthread_sigmask(SIG_BLOCK, &mask, null);
			//}
		} catch {}
	}
	static this() {
		blockSignals();
		g_signalsBlocked = true;
	}
}
version(OSX) {
	import libasync.internals.kqueue;
	const EPOLL = false;
}
version(FreeBSD) {
	import libasync.internals.kqueue;
	const EPOLL = false;
}

__gshared Mutex g_mutex;

static if (!EPOLL) {
	private struct DWFileInfo {
		fd_t folder;
		Path path;
		SysTime lastModified;
		bool is_dir;
	}
}

private struct DWFolderInfo {
	WatchInfo wi;
	fd_t fd;
}

package struct EventLoopImpl {
	static if (EPOLL) {
		pragma(msg, "Using Linux EPOLL for events");
	}
	else /* if KQUEUE */
	{
		pragma(msg, "Using FreeBSD KQueue for events");
	}

package:
	alias error_t = EPosix;

nothrow:
private:

	/// members
	EventLoop m_evLoop;
	ushort m_instanceId;
	bool m_started;
	StatusInfo m_status;
	error_t m_error = EPosix.EOK;
	EventInfo* m_evSignal;
	static if (EPOLL){
		fd_t m_epollfd;
		HashMap!(Tuple!(fd_t, uint), DWFolderInfo) m_dwFolders; // uint = inotify_add_watch(Path)
	}
	else /* if KQUEUE */
	{
		fd_t m_kqueuefd;
		HashMap!(fd_t, EventInfo*) m_watchers; // fd_t = id++ per AsyncDirectoryWatcher
		HashMap!(fd_t, DWFolderInfo) m_dwFolders; // fd_t = open(folder)
		HashMap!(fd_t, DWFileInfo) m_dwFiles; // fd_t = open(file)
		HashMap!(fd_t, Array!(DWChangeInfo)*) m_changes; // fd_t = id++ per AsyncDirectoryWatcher

	}

package:
	
	/// workaround for IDE indent bug on too big files
	mixin RunKill!();

	@property bool started() const {
		return m_started;
	}

	bool init(EventLoop evl)
	in { assert(!m_started); }
	body
	{

		import core.atomic;
		shared static ushort i;
		string* failer = null;


		m_instanceId = i;
		static if (!EPOLL) g_threadId = new size_t(cast(size_t)m_instanceId);

		core.atomic.atomicOp!"+="(i, cast(ushort) 1);
		m_evLoop = evl;

		import core.thread;
		try Thread.getThis().priority = Thread.PRIORITY_MAX;
		catch (Exception e) { assert(false, "Could not set thread priority"); }

		try
			if (!g_mutex)
				g_mutex = new Mutex;
		catch {}

		static if (EPOLL)
		{

			if (!g_signalsBlocked)
				blockSignals();
			assert(m_instanceId <= __libc_current_sigrtmax(), "An additional event loop is unsupported due to SIGRTMAX restrictions in Linux Kernel");
			m_epollfd = epoll_create1(0);

			if (catchError!"epoll_create1"(m_epollfd))
				return false;
				
			import core.sys.linux.sys.signalfd;
			import core.thread : getpid;

			fd_t err;
			fd_t sfd;

			sigset_t mask;

			try {
				sigemptyset(&mask);
				sigaddset(&mask, __libc_current_sigrtmin());
				err = pthread_sigmask(SIG_BLOCK, &mask, null);
				if (catchError!"sigprocmask"(err))
				{
					m_status.code = Status.EVLOOP_FAILURE;
					return false;
				}
			} catch { }



			sfd = signalfd(-1, &mask, SFD_NONBLOCK);
			assert(sfd > 0, "Failed to setup signalfd in epoll");

			EventType evtype;

			epoll_event _event;
			_event.events = EPOLLIN;
			evtype = EventType.Signal;
			try 
				m_evSignal = FreeListObjectAlloc!EventInfo.alloc(sfd, evtype, EventObject.init, m_instanceId);
			catch (Exception e){ 
				assert(false, "Allocation error"); 
			}
			_event.data.ptr = cast(void*) m_evSignal;

			err = epoll_ctl(m_epollfd, EPOLL_CTL_ADD, sfd, &_event);
			if (catchError!"EPOLL_CTL_ADD(sfd)"(err))
			{
				return false;
			}

		}
		else /* if KQUEUE */ 
		{
			try {
				if (!gs_queueMutex) {
					gs_queueMutex = FreeListObjectAlloc!ReadWriteMutex.alloc();
					gs_signalQueue = Array!(Array!AsyncSignal)();
					gs_idxQueue = Array!(Array!size_t)();
				}
				if (g_evIdxAvailable.empty) {
					g_evIdxAvailable.reserve(32);
					
					foreach (k; g_evIdxAvailable.length .. g_evIdxAvailable.capacity) {
						g_evIdxAvailable.insertBack(k + 1);
					}
					g_evIdxCapacity = 32;
					g_idxCapacity = 32;
				}
			} catch { assert(false, "Initialization failed"); }
			m_kqueuefd = kqueue();
			int err;
			try {
				sigset_t mask;
				sigemptyset(&mask);
				sigaddset(&mask, SIGXCPU);
				
				err = sigprocmask(SIG_BLOCK, &mask, null);
			} catch {}

			EventType evtype = EventType.Signal;

			// use GC because FreeListObjectAlloc fails at emplace for shared objects
			try 
				m_evSignal = FreeListObjectAlloc!EventInfo.alloc(SIGXCPU, evtype, EventObject.init, m_instanceId);
			catch (Exception e) {
				assert(false, "Failed to allocate resources");
			}

			if (catchError!"siprocmask"(err))
				return 0;

			kevent_t _event;
			EV_SET(&_event, SIGXCPU, EVFILT_SIGNAL, EV_ADD | EV_ENABLE, 0, 0, m_evSignal);
			err = kevent(m_kqueuefd, &_event, 1, null, 0, null);
			if (catchError!"kevent_add(SIGXCPU)"(err))
				assert(false, "Add SIGXCPU failed at kevent call");
		}

		try log("init in thread " ~ Thread.getThis().name); catch {}

		return true;
	}

	void exit() {
		import core.sys.posix.unistd : close;
		static if (EPOLL) {
			close(m_epollfd); // not necessary?

			// not necessary:
			//try FreeListObjectAlloc!EventInfo.free(m_evSignal);
			//catch (Exception e) { assert(false, "Failed to free resources"); }

		}
		else
			close(m_kqueuefd);
	}

	@property const(StatusInfo) status() const {
		return m_status;
	}

	@property string error() const {
		string* ptr;
		return ((ptr = (m_error in EPosixMessages)) !is null) ? *ptr : string.init;
	}

	bool loop(Duration timeout = 0.seconds)
	//in { assert(Fiber.getThis() is null); }
	{

		import libasync.internals.memory;
		bool success = true;
		int num;

		static if (EPOLL) {

			static align(1) epoll_event[] events;
			if (events is null)
			{
				try events = new epoll_event[128];
				catch (Exception e) {
					assert(false, "Could not allocate events array: " ~ e.msg);
				}
			}
			int timeout_ms;
			if (timeout == 0.seconds)
				timeout_ms = -1;
			else timeout_ms = cast(int)timeout.total!"msecs";

			/// Retrieve pending events
			num = epoll_wait(m_epollfd, cast(epoll_event*)&events[0], 128, timeout_ms);

			assert(events !is null && events.length <= 128);

			
		}
		else /* if KQUEUE */ {
			import core.sys.posix.time : time_t;
			import core.sys.posix.config : c_long;
			static kevent_t[] events;
			if (events.length == 0) {
				try events = allocArray!kevent_t(manualAllocator(), 128); 
				catch (Exception e) { assert(false, "Could not allocate events array"); }				
			}
			time_t secs = timeout.split!("seconds", "nsecs")().seconds;
			c_long ns = timeout.split!("seconds", "nsecs")().nsecs;
			auto tspec = libasync.internals.kqueue.timespec(secs, ns);

			num = kevent(m_kqueuefd, null, 0, cast(kevent_t*) events, cast(int) events.length, &tspec);

		}

		auto errors = [	tuple(EINTR, Status.EVLOOP_TIMEOUT) ];
		
		if (catchEvLoopErrors!"event_poll'ing"(num, errors)) 
			return false;

		if (num > 0)
			log("Got " ~ num.to!string ~ " event(s)");

		foreach(i; 0 .. num) {
			success = false;
			m_status = StatusInfo.init;
			static if (EPOLL) 
			{
				epoll_event _event = events[i];
				try log("Event " ~ i.to!string ~ " of: " ~ events.length.to!string); catch {}
				EventInfo* info = cast(EventInfo*) _event.data.ptr;
				int event_flags = cast(int) _event.events;
			}
			else /* if KQUEUE */
			{
				kevent_t _event = events[i];
				EventInfo* info = cast(EventInfo*) _event.udata;
				//log("Got info");
				int event_flags = (_event.filter << 16) | (_event.flags & 0xffff);
				//log("event flags");
			}

			//if (info.owner != m_instanceId)
			//	try log("Event " ~ (cast(int)(info.evType)).to!string ~ " is invalid: supposidly created in instance #" ~ info.owner.to!string ~ ", received in " ~ m_instanceId.to!string ~ " event: " ~ event_flags.to!string);
			//	catch{}
			//log("owner");
			final switch (info.evType) {
				case EventType.TCPAccept:
					if (info.fd == 0)
						break;
					success = onTCPAccept(info.fd, info.evObj.tcpAcceptHandler, event_flags);
					break;

				case EventType.Notifier:

					log("Got notifier!");
					try info.evObj.notifierHandler();
					catch (Exception e) {
						setInternalError!"notifierHandler"(Status.ERROR);
					}
					break;

				case EventType.DirectoryWatcher:
					log("Got DirectoryWatcher event!");
					static if (!EPOLL) {
						// in KQUEUE all events will be consumed here, because they must be pre-processed
						try {
							DWFileEvent fevent;
							if (_event.fflags & (NOTE_LINK | NOTE_WRITE))
								fevent = DWFileEvent.CREATED;
							else if (_event.fflags & NOTE_DELETE)
								fevent = DWFileEvent.DELETED;
							else if (_event.fflags & (NOTE_ATTRIB | NOTE_EXTEND | NOTE_WRITE))
								fevent = DWFileEvent.MODIFIED;
							else if (_event.fflags & NOTE_RENAME)
								fevent = DWFileEvent.MOVED_FROM;
							else if (_event.fflags & NOTE_RENAME)
								fevent = DWFileEvent.MOVED_TO;
							else
								assert(false, "No event found?");

							DWFolderInfo fi = m_dwFolders.get(cast(fd_t)_event.ident, DWFolderInfo.init);

							if (fi == DWFolderInfo.init) {
								DWFileInfo tmp = m_dwFiles.get(cast(fd_t)_event.ident, DWFileInfo.init);
								assert(tmp != DWFileInfo.init, "The event loop returned an invalid file's file descriptor for the directory watcher");
								fi = m_dwFolders.get(cast(fd_t) tmp.folder, DWFolderInfo.init);
								assert(fi != DWFolderInfo.init, "The event loop returned an invalid folder file descriptor for the directory watcher");
							}

							// all recursive events will be generated here
							if (!compareFolderFiles(fi, fevent)) {
								continue;
							}

						} catch (Exception e) {
							log("Could not process DirectoryWatcher event: " ~ e.msg);
							break;
						}

					}

					try info.evObj.dwHandler();
					catch (Exception e) {
						setInternalError!"dwHandler"(Status.ERROR);
					}
					break;

				case EventType.Timer:
					try log("Got timer! " ~ info.fd.to!string); catch {}
					static if (EPOLL) {
						static long val;
						import core.sys.posix.unistd : read;
						read(info.evObj.timerHandler.ctxt.id, &val, long.sizeof);
					}
					try info.evObj.timerHandler();
					catch (Exception e) {
						setInternalError!"timerHandler"(Status.ERROR);
					}
					static if (!EPOLL) {
						if (info.evObj.timerHandler.ctxt.oneShot && !info.evObj.timerHandler.ctxt.rearmed) {
							destroyIndex(info.evObj.timerHandler.ctxt);
							info.evObj.timerHandler.ctxt.id = 0;
						}
					}
					break;

				case EventType.Signal:
					try log("Got signal!"); catch {}

					static if (EPOLL) {
						
						try log("Got signal: " ~ info.fd.to!string ~ " of type: " ~ info.evType.to!string); catch {}
						import core.sys.linux.sys.signalfd : signalfd_siginfo;
						import core.sys.posix.unistd : read;
						signalfd_siginfo fdsi;
						fd_t err = cast(fd_t)read(info.fd, &fdsi, fdsi.sizeof);
						shared AsyncSignal sig = cast(shared AsyncSignal) cast(void*) fdsi.ssi_ptr;

						try sig.handler();
						catch (Exception e) {
							setInternalError!"signal handler"(Status.ERROR);
						}


					}
					else /* if KQUEUE */
					{
						static AsyncSignal[] sigarr;
						
						if (sigarr.length == 0) {
							try sigarr = new AsyncSignal[32]; 
							catch (Exception e) { assert(false, "Could not allocate signals array"); }		
						}

						bool more = popSignals(sigarr);
						foreach (AsyncSignal sig; sigarr)
						{
							shared AsyncSignal ptr = cast(shared AsyncSignal) sig;
							if (ptr is null)
								break;
							try (cast(shared AsyncSignal)sig).handler();
							catch (Exception e) {
								setInternalError!"signal handler"(Status.ERROR);
							}
						}
					}
					break;

				case EventType.UDPSocket:
					import core.sys.posix.unistd : close;
					success = onUDPTraffic(info.fd, info.evObj.udpHandler, event_flags);

					nothrow void abortHandler(bool graceful) {

						close(info.fd);
						info.evObj.udpHandler.conn.socket = 0;
						try info.evObj.udpHandler(UDPEvent.ERROR);
						catch (Exception e) { }
						try FreeListObjectAlloc!EventInfo.free(info);
						catch (Exception e){ assert(false, "Error freeing resources"); }
					}
					
					if (!success && m_status.code == Status.ABORT) {
						abortHandler(true);
						
					}
					else if (!success && m_status.code == Status.ERROR) {
						abortHandler(false); 
					}
					break;
				case EventType.TCPTraffic:
					assert(info.evObj.tcpEvHandler.conn !is null, "TCP Connection invalid");

					success = onTCPTraffic(info.fd, info.evObj.tcpEvHandler, event_flags, info.evObj.tcpEvHandler.conn);

					nothrow void abortTCPHandler(bool graceful) {

						nothrow void closeAll() {
							try log("closeAll()"); catch {}
							if (info.evObj.tcpEvHandler.conn.connected)
								closeSocket(info.fd, true, true);
							
							info.evObj.tcpEvHandler.conn.socket = 0;
						}

						/// Close the connection after an unexpected socket error
						if (graceful) {
							try info.evObj.tcpEvHandler(TCPEvent.CLOSE);
							catch (Exception e) { }
							closeAll();
						}

						/// Kill the connection after an internal error
						else {
							try info.evObj.tcpEvHandler(TCPEvent.ERROR);
							catch (Exception e) { }
							closeAll();
						}

						if (info.evObj.tcpEvHandler.conn.inbound) {
							log("Freeing inbound connection FD#" ~ info.fd.to!string);
							try FreeListObjectAlloc!AsyncTCPConnection.free(info.evObj.tcpEvHandler.conn);
							catch (Exception e){ assert(false, "Error freeing resources"); }
						}
						try FreeListObjectAlloc!EventInfo.free(info);
						catch (Exception e){ assert(false, "Error freeing resources"); }
					}

					if (!success && m_status.code == Status.ABORT) {
						abortTCPHandler(true);
					}
					else if (!success && m_status.code == Status.ERROR) {
						abortTCPHandler(false);
					}

					break;
			}

		}
		return success;
	}

	bool setOption(T)(fd_t fd, TCPOption option, in T value) {
		m_status = StatusInfo.init;
		import std.traits : isIntegral;

		import libasync.internals.socket_compat : socklen_t, setsockopt, SO_REUSEADDR, SO_KEEPALIVE, SO_RCVBUF, SO_SNDBUF, SO_RCVTIMEO, SO_SNDTIMEO, SO_LINGER, SOL_SOCKET, IPPROTO_TCP, TCP_NODELAY, TCP_QUICKACK, TCP_KEEPCNT, TCP_KEEPINTVL, TCP_KEEPIDLE, TCP_CONGESTION, TCP_CORK, TCP_DEFER_ACCEPT;
		int err;
		nothrow bool errorHandler() {
			if (catchError!"setOption:"(err)) {
				try m_status.text ~= option.to!string;
				catch (Exception e){ assert(false, "to!string conversion failure"); }
				return false;
			}

			return true;
		}
		final switch (option) {
			case TCPOption.NODELAY: // true/false
				static if (!is(T == bool))
					assert(false, "NODELAY value type must be bool, not " ~ T.stringof);
				else {
					int val = value?1:0;
					socklen_t len = val.sizeof;
					err = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &val, len);
					return errorHandler();
				}
			case TCPOption.REUSEADDR: // true/false
				static if (!is(T == bool))
					assert(false, "REUSEADDR value type must be bool, not " ~ T.stringof);
				else {
					int val = value?1:0;
					socklen_t len = val.sizeof;
					err = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, len);
					if (!errorHandler())
						return false;

					// BSD systems have SO_REUSEPORT
					import libasync.internals.socket_compat : SO_REUSEPORT;
					err = setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &val, len);
					
					// Not all linux kernels support SO_REUSEPORT
					version(linux) {
						// ignore invalid and not supported errors on linux
						if (errno == EINVAL || errno == ENOPROTOOPT) {
							return true;
						}						
					} 

					return errorHandler();
				}
			case TCPOption.QUICK_ACK:
				static if (!is(T == bool))
					assert(false, "QUICK_ACK value type must be bool, not " ~ T.stringof);
				else {
					static if (EPOLL) {
						int val = value?1:0;
						socklen_t len = val.sizeof;
						err = setsockopt(fd, IPPROTO_TCP, TCP_QUICKACK, &val, len);
						return errorHandler();
					}
					else /* not linux */ {
						return false;
					}
				}
			case TCPOption.KEEPALIVE_ENABLE: // true/false
				static if (!is(T == bool))
					assert(false, "KEEPALIVE_ENABLE value type must be bool, not " ~ T.stringof);
				else
				{
					int val = value?1:0;
					socklen_t len = val.sizeof;
					err = setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, &val, len);
					return errorHandler();
				}
			case TCPOption.KEEPALIVE_COUNT: // ##
				static if (!isIntegral!T)
					assert(false, "KEEPALIVE_COUNT value type must be integral, not " ~ T.stringof);
				else {
					int val = value.total!"msecs".to!uint;
					socklen_t len = val.sizeof;
					err = setsockopt(fd, IPPROTO_TCP, TCP_KEEPCNT, &val, len);
					return errorHandler();
				}
			case TCPOption.KEEPALIVE_INTERVAL: // wait ## seconds
				static if (!is(T == Duration))
					assert(false, "KEEPALIVE_INTERVAL value type must be Duration, not " ~ T.stringof);
				else {
					int val;
					try val = value.total!"seconds".to!uint; catch { return false; }
					socklen_t len = val.sizeof;
					err = setsockopt(fd, IPPROTO_TCP, TCP_KEEPINTVL, &val, len);
					return errorHandler();
				}
			case TCPOption.KEEPALIVE_DEFER: // wait ## seconds until start
				static if (!is(T == Duration))
					assert(false, "KEEPALIVE_DEFER value type must be Duration, not " ~ T.stringof);
				else {
					int val;
					try val = value.total!"seconds".to!uint; catch { return false; }
					socklen_t len = val.sizeof;
					err = setsockopt(fd, IPPROTO_TCP, TCP_KEEPIDLE, &val, len);
					return errorHandler();
				}
			case TCPOption.BUFFER_RECV: // bytes
				static if (!isIntegral!T)
					assert(false, "BUFFER_RECV value type must be integral, not " ~ T.stringof);
				else {
					int val = value.to!int;
					socklen_t len = val.sizeof;
					err = setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &val, len);
					return errorHandler();
				}
			case TCPOption.BUFFER_SEND: // bytes
				static if (!isIntegral!T)
					assert(false, "BUFFER_SEND value type must be integral, not " ~ T.stringof);
				else {
					int val = value.to!int;
					socklen_t len = val.sizeof;
					err = setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &val, len);
					return errorHandler();
				}
			case TCPOption.TIMEOUT_RECV:
				static if (!is(T == Duration))
					assert(false, "TIMEOUT_RECV value type must be Duration, not " ~ T.stringof);
				else {
					import core.sys.posix.sys.time : timeval;
					time_t secs = cast(time_t) value.split!("seconds", "usecs")().seconds;
					suseconds_t us;
					try us = value.split!("seconds", "usecs")().usecs.to!suseconds_t; catch {}
					timeval t = timeval(secs, us);
					socklen_t len = t.sizeof;
					err = setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &t, len);
					return errorHandler();
				}
			case TCPOption.TIMEOUT_SEND:
				static if (!is(T == Duration))
					assert(false, "TIMEOUT_SEND value type must be Duration, not " ~ T.stringof);
				else {
					import core.sys.posix.sys.time : timeval;
					time_t secs = value.split!("seconds", "usecs")().seconds;
					suseconds_t us;
					try us = value.split!("seconds", "usecs")().usecs.to!suseconds_t; catch {}
					timeval t = timeval(secs, us);
					socklen_t len = t.sizeof;
					err = setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, &t, len);
					return errorHandler();
				}
			case TCPOption.TIMEOUT_HALFOPEN:
				static if (!is(T == Duration))
					assert(false, "TIMEOUT_SEND value type must be Duration, not " ~ T.stringof);
				else {
					uint val;
					try val = value.total!"msecs".to!uint; catch {
						return false;
					}
					socklen_t len = val.sizeof;
					err = setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, &val, len);
					return errorHandler();
				}
			case TCPOption.LINGER: // bool onOff, int seconds
				static if (!is(T == Tuple!(bool, int)))
					assert(false, "LINGER value type must be Tuple!(bool, int), not " ~ T.stringof);
				else {
					linger l = linger(val[0]?1:0, val[1]);
					socklen_t llen = l.sizeof;
					err = setsockopt(fd, SOL_SOCKET, SO_LINGER, &l, llen);
					return errorHandler();
				}
			case TCPOption.CONGESTION:
				static if (!isIntegral!T)
					assert(false, "CONGESTION value type must be integral, not " ~ T.stringof);
				else {
					int val = value.to!int;
					len = int.sizeof;
					err = setsockopt(fd, IPPROTO_TCP, TCP_CONGESTION, &val, len);
					return errorHandler();
				}
			case TCPOption.CORK:
				static if (!isIntegral!T)
					assert(false, "CORK value type must be int, not " ~ T.stringof);
				else {
					static if (EPOLL) {
						int val = value.to!int;
						socklen_t len = val.sizeof;
						err = setsockopt(fd, IPPROTO_TCP, TCP_CORK, &val, len);
						return errorHandler();
					}
					else /* if KQUEUE */ {
						int val = value.to!int;
						socklen_t len = val.sizeof;
						err = setsockopt(fd, IPPROTO_TCP, TCP_NOPUSH, &val, len);
						return errorHandler();

					}
				}
			case TCPOption.DEFER_ACCEPT: // seconds
				static if (!isIntegral!T)
					assert(false, "DEFER_ACCEPT value type must be integral, not " ~ T.stringof);
				else {
					static if (EPOLL) {
						int val = value.to!int;
						socklen_t len = val.sizeof;
						err = setsockopt(fd, IPPROTO_TCP, TCP_DEFER_ACCEPT, &val, len);
						return errorHandler();
					}
					else /* if KQUEUE */ {
						// todo: Emulate DEFER_ACCEPT with ACCEPT_FILTER(9)
						/*int val = value.to!int;
						socklen_t len = val.sizeof;
						err = setsockopt(fd, SOL_SOCKET, SO_ACCEPTFILTER, &val, len);
						return errorHandler();
						*/
						assert(false, "TCPOption.DEFER_ACCEPT is not implemented");
					}
				}
		}

	}

	uint recv(in fd_t fd, ref ubyte[] data)
	{
		try log("Recv from FD: " ~ fd.to!string); catch {}
		m_status = StatusInfo.init;
		import libasync.internals.socket_compat : recv;
		int ret = cast(int) recv(fd, cast(void*) data.ptr, data.length, cast(int)0);
		
		static if (LOG) log(".recv " ~ ret.to!string ~ " bytes of " ~ data.length.to!string ~ " @ " ~ fd.to!string);
		if (catchError!".recv"(ret)){ // ret == SOCKET_ERROR == -1 ?
			if (m_error == EPosix.EWOULDBLOCK || m_error == EPosix.EAGAIN)
				m_status.code = Status.ASYNC;

			return 0; // TODO: handle some errors more specifically
		}

		m_status.code = Status.OK;
		
		return cast(uint) ret < 0 ? 0 : ret;
	}
	
	uint send(in fd_t fd, in ubyte[] data)
	{
		try log("Send to FD: " ~ fd.to!string); catch {}
		m_status = StatusInfo.init;
		import libasync.internals.socket_compat : send;
		int ret = cast(int) send(fd, cast(const(void)*) data.ptr, data.length, cast(int)0);

		if (catchError!"send"(ret)) { // ret == -1
			if (m_error == EPosix.EWOULDBLOCK || m_error == EPosix.EAGAIN) {
				m_status.code = Status.ASYNC;
				return 0;
			}
		}
		m_status.code = Status.OK;
		return cast(uint) ret < 0 ? 0 : ret;
	}

	uint recvFrom(in fd_t fd, ref ubyte[] data, ref NetworkAddress addr)
	{
		import libasync.internals.socket_compat : recvfrom, AF_INET6, AF_INET, socklen_t;

		m_status = StatusInfo.init;

		addr.family = AF_INET6;
		socklen_t addrLen = addr.sockAddrLen;
		long ret = recvfrom(fd, cast(void*) data.ptr, data.length, 0, addr.sockAddr, &addrLen);
		
		if (addrLen < addr.sockAddrLen) {
			addr.family = AF_INET;
		}
		
		try log("RECVFROM " ~ ret.to!string ~ "B"); catch {}
		if (catchError!".recvfrom"(ret)) { // ret == -1
			if (m_error == EPosix.EWOULDBLOCK || m_error == EPosix.EAGAIN)
				m_status.code = Status.ASYNC;
			return 0;
		}

		m_status.code = Status.OK;
		
		return cast(uint) ret;
	}
	
	uint sendTo(in fd_t fd, in ubyte[] data, in NetworkAddress addr)
	{
		import libasync.internals.socket_compat : sendto;

		m_status = StatusInfo.init;

		try log("SENDTO " ~ data.length.to!string ~ "B");
		catch{}
		long ret = sendto(fd, cast(void*) data.ptr, data.length, 0, addr.sockAddr, addr.sockAddrLen);
		
		if (catchError!".sendto"(ret)) { // ret == -1
			if (m_error == EPosix.EWOULDBLOCK || m_error == EPosix.EAGAIN)
				m_status.code = Status.ASYNC;
			return 0;
		}

		m_status.code = Status.OK;
		return cast(uint) ret;
	}

	NetworkAddress localAddr(in fd_t fd, bool ipv6) {
		NetworkAddress ret;
		import libasync.internals.socket_compat : getsockname, AF_INET, AF_INET6, socklen_t, sockaddr;

		if (ipv6)
			ret.family = AF_INET6;
		else
			ret.family = AF_INET;

		socklen_t len = ret.sockAddrLen;
		int err = getsockname(fd, ret.sockAddr, &len);
		if (catchError!"getsockname"(err))
			return NetworkAddress.init;
		if (len > ret.sockAddrLen)
			ret.family = AF_INET6;

		return ret;
	}

	bool notify(in fd_t fd, AsyncNotifier ctxt)
	{
		static if (EPOLL)
		{
			import core.sys.posix.unistd : write;

			long val = 1;
			fd_t err = cast(fd_t) write(fd, &val, long.sizeof);
			
			if (catchError!"write(notify)"(err)) {
				return false;
			}
			return true;
		}
		else /* if KQUEUE */
		{			
			kevent_t _event;
			EV_SET(&_event, fd, EVFILT_USER, EV_ENABLE | EV_CLEAR, NOTE_TRIGGER | 0x1, 0, ctxt.evInfo);
			int err = kevent(m_kqueuefd, &_event, 1, null, 0, null);
			
			if (catchError!"kevent_notify"(err)) {
				return false;
			}
			return true;
		}
	}

	bool notify(in fd_t fd, shared AsyncSignal ctxt)
	{
		static if (EPOLL) 
		{

			sigval sigvl;
			fd_t err;
			sigvl.sival_ptr = cast(void*) ctxt;
			try err = pthread_sigqueue(ctxt.pthreadId, fd, sigvl); catch {}
			if (catchError!"sigqueue"(err)) {
				return false;
			}
		}
		else /* if KQUEUE */ 
		{

			import core.thread : getpid;

			addSignal(ctxt);

			try {
				log("Notified fd: " ~ fd.to!string ~ " of PID " ~ getpid().to!string); 
				int err = core.sys.posix.signal.kill(getpid(), SIGXCPU);
				if (catchError!"notify(signal)"(err))
					assert(false, "Signal could not be raised");
			} catch {}
		}

		return true;
	}

	// no known uses
	uint read(in fd_t fd, ref ubyte[] data)
	{
		m_status = StatusInfo.init;
		return 0;
	}

	// no known uses
	uint write(in fd_t fd, in ubyte[] data)
	{
		m_status = StatusInfo.init;
		return 0;
	}

	uint watch(in fd_t fd, in WatchInfo info) {
		// note: info.wd is still 0 at this point.
		m_status = StatusInfo.init;
		import core.sys.linux.sys.inotify;
		import std.file : dirEntries, isDir, SpanMode;

		static if (EPOLL) {
			// Manually handle recursivity... All events show up under the same inotify
			uint events = info.events; // values for this API were pulled from inotify
			if (events & IN_DELETE)
				events |= IN_DELETE_SELF;
			if (events & IN_MOVED_FROM)
				events |= IN_MOVE_SELF;

			nothrow fd_t addFolderRecursive(Path path) {
				fd_t ret;
				try {
					ret = inotify_add_watch(fd, path.toNativeString().toStringz, events);
					if (catchError!"inotify_add_watch"(ret))
						return fd_t.init;
					try log("inotify_add_watch(" ~ DWFolderInfo(WatchInfo(info.events, path, info.recursive, ret), fd).to!string ~ ")"); catch {}
					assert(m_dwFolders.get(tuple(cast(fd_t) fd, cast(uint)ret), DWFolderInfo.init) == DWFolderInfo.init, "Could not get a unique watch descriptor for path, got: " ~ m_dwFolders[tuple(cast(fd_t)fd, cast(uint)ret)].to!string);
					m_dwFolders[tuple(cast(fd_t)fd, cast(uint)ret)] = DWFolderInfo(WatchInfo(info.events, path, info.recursive, ret), fd);
					if (info.recursive) {
						foreach (de; path.toNativeString().dirEntries(SpanMode.shallow))
						{
							Path de_path = Path(de.name);
							if (!de_path.absolute)
								de_path = path ~ Path(de.name);
							if (isDir(de_path.toNativeString()))
								if (addFolderRecursive(de_path) == 0)
									return 0;
						}
					}

				} catch (Exception e) { 
					try setInternalError!"inotify_add_watch"(Status.ERROR, "Could not add directory " ~ path.toNativeString() ~ ": " ~ e.toString() ); catch {}
					return 0; 
				}

				return ret;
			}

			return addFolderRecursive(info.path);

		} else /* if KQUEUE */ {
			/// Manually handle recursivity & file tracking. Each folder is an event! 
			/// E.g. file creation shows up as a folder change, we must be prepared to seek the file.
			import core.sys.posix.fcntl;
			import libasync.internals.kqueue;

			uint events;
			if (info.events & DWFileEvent.CREATED)
				events |= NOTE_LINK | NOTE_WRITE;
			if (info.events & DWFileEvent.DELETED)
				events |= NOTE_DELETE;
			if (info.events & DWFileEvent.MODIFIED)
				events |= NOTE_ATTRIB | NOTE_EXTEND | NOTE_WRITE;
			if (info.events & DWFileEvent.MOVED_FROM)
				events |= NOTE_RENAME;
			if (info.events & DWFileEvent.MOVED_TO)
				events |= NOTE_RENAME;

			EventInfo* evinfo;
			try evinfo = m_watchers[fd]; catch { assert(false, "Could retrieve event info, directory watcher was not initialized properly, or you are operating on a closed directory watcher."); }

			/// we need a file descriptor for the containers, so we open files but we don't monitor them
			/// todo: track indexes internally?
			nothrow fd_t addRecursive(Path path, bool is_dir) {
				int ret;
				try {
					log("Adding path: " ~ path.toNativeString());

					ret = open(path.toNativeString().toStringz, O_EVTONLY);
					if (catchError!"open(watch)"(ret))
						return 0;

					if (is_dir)
						m_dwFolders[ret] = DWFolderInfo(WatchInfo(info.events, path, info.recursive, ret), fd);

					kevent_t _event;
					
					EV_SET(&_event, ret, EVFILT_VNODE, EV_ADD | EV_CLEAR, events, 0, cast(void*) evinfo);
					
					int err = kevent(m_kqueuefd, &_event, 1, null, 0, null);
					
					if (catchError!"kevent_timer_add"(err))
						return 0;


					if (is_dir) foreach (de; dirEntries(path.toNativeString(), SpanMode.shallow)) {
						Path filePath = Path(de.name);
						if (!filePath.absolute)
							filePath = path ~ filePath;
						fd_t fwd;
						if (info.recursive && isDir(filePath.toNativeString()))
							fwd = addRecursive(filePath, true);
						else {
							fwd = addRecursive(filePath, false); // gets an ID but will not scan
							m_dwFiles[fwd] = DWFileInfo(ret, filePath, de.timeLastModified, isDir(filePath.toNativeString()));
						}
						
					}

				} catch (Exception e) { 
					try setInternalError!"inotify_add_watch"(Status.ERROR, "Could not add directory " ~ path.toNativeString() ~ ": " ~ e.msg);  catch {}
					return 0; 
				}
				return ret;
			}

			fd_t wd;

			try {
				wd = addRecursive(info.path, isDir(info.path.toNativeString()));

				if (wd == 0)
					return 0;

			}
			catch (Exception e) {
				setInternalError!"dw.watch"(Status.ERROR, "Failed to watch directory: " ~ e.msg); 
			}

			return cast(uint) wd;
		}
	}

	bool unwatch(in fd_t fd, in uint wd) {
		// the wd can be used with m_dwFolders to find the DWFolderInfo
		// and unwatch everything recursively.

		m_status = StatusInfo.init;
		static if (EPOLL) {
			/// If recursive, all subfolders must also be unwatched recursively by removing them
			/// from containers and from inotify
			import core.sys.linux.sys.inotify;

			nothrow bool removeAll(DWFolderInfo fi) {
				int err;
				try {

					bool inotify_unwatch(uint wd) {
						err = inotify_rm_watch(fd, wd);

						if (catchError!"inotify_rm_watch"(err))
							return false;
						return true;
					}

					if (!inotify_unwatch(fi.wi.wd))
						return false;

					/*foreach (ref const fd_t id, ref const DWFileInfo file; m_dwFiles)
					{
						if (file.folder == fi.wi.wd) {
							inotify_unwatch(id);
							m_dwFiles.remove(id);
						}
					}*/
					m_dwFolders.remove(tuple(cast(fd_t)fd, fi.wi.wd)); 

					if (fi.wi.recursive) {
						// find all subdirectories by comparing the path
						Array!uint remove_list;
						foreach (ref const DWFolderInfo folder; m_dwFolders) {
							if (folder.fd == fi.fd && folder.wi.path.startsWith(fi.wi.path)) {

								if (!inotify_unwatch(folder.wi.wd))
									return false;

								remove_list.insertBack(fi.wi.wd);
							}
						}
						foreach (rm_wd; remove_list[])
							m_dwFolders.remove(tuple(cast(fd_t) fd, rm_wd));

					}
					return true;
				} catch (Exception e) { 
					try setInternalError!"inotify_rm_watch"(Status.ERROR, "Could not unwatch directory: " ~ e.toString()); catch {}
					return false; 
				}
			}

			DWFolderInfo info;

			try {
				info = m_dwFolders.get(tuple(cast(fd_t) fd, cast(uint) wd), DWFolderInfo.init);
				if (info == DWFolderInfo.init) {
					setInternalError!"dwFolders.get(wd)"(Status.ERROR, "Could not find watch info for wd " ~ wd.to!string);
					return false;
				}
			} catch { }

			return removeAll(info);
		}
		else /* if KQUEUE */ {

			/// Recursivity must be handled manually, so we must unwatch subfiles and subfolders
			/// recursively, remove the container entries, close the file descriptor, and disable the vnode events.

			nothrow bool removeAll(DWFolderInfo fi) {
				import core.sys.posix.unistd : close;


				bool event_unset(uint id) {
					kevent_t _event;
					EV_SET(&_event, cast(int) id, EVFILT_VNODE, EV_DELETE, 0, 0, null);
					int err = kevent(m_kqueuefd, &_event, 1, null, 0, null);
					if (catchError!"kevent_unwatch"(err))
						return false;
					return true;
				}

				bool removeFolder(uint wd) {
					if (!event_unset(fi.wi.wd))
						return false;
					m_dwFolders.remove(fi.wi.wd);
					int err = close(fi.wi.wd);
					if (catchError!"close dir"(err))
						return false;
					return true;
				}

				try {
					removeFolder(fi.wi.wd);

					if (fi.wi.recursive) {
						import std.container.array;
						Array!fd_t remove_list; // keep track of unwatched folders recursively
						Array!fd_t remove_file_list;
						// search for subfolders and unset them / close their wd
						foreach (ref const DWFolderInfo folder; m_dwFolders) {
							if (folder.fd == fi.fd && folder.wi.path.startsWith(fi.wi.path)) {
								 
								if (!event_unset(folder.wi.wd))
									return false;

								// search for subfiles, close their descriptors and remove them from the file list
								foreach (ref const fd_t fwd, ref const DWFileInfo file; m_dwFiles) {
									if (file.folder == folder.wi.wd) {
										close(fwd);
										remove_file_list.insertBack(fwd); // to be removed from m_dwFiles without affecting the loop
									}
								}

								remove_list.insertBack(folder.wi.wd); // to be removed from m_dwFolders without affecting the loop
							}
						}

						foreach (wd; remove_file_list[])
							m_dwFiles.remove(wd);

						foreach (rm_wd; remove_list[])
							removeFolder(rm_wd);


					}
				} catch (Exception e) {
					try setInternalError!"dwFolders.get(wd)"(Status.ERROR, "Could not close the folder " ~ fi.to!string ~ ": " ~ e.toString()); catch {}
					return false;
				}

				return true;
			}

			DWFolderInfo info;
			try info = m_dwFolders.get(wd, DWFolderInfo.init); catch {}

			if (!removeAll(info))
				return false;
			return true;
		}
	}

	// returns the amount of changes
	uint readChanges(in fd_t fd, ref DWChangeInfo[] dst) {
		m_status = StatusInfo.init;

		static if (EPOLL) {
			assert(dst.length > 0, "DirectoryWatcher called with 0 length DWChangeInfo array");
			import core.sys.linux.sys.inotify;
			import core.sys.posix.unistd : read;
			import core.stdc.stdio : FILENAME_MAX;
			import core.stdc.string : strlen;
			ubyte[inotify_event.sizeof + FILENAME_MAX + 1] buf = void;
			ssize_t nread = read(fd, buf.ptr, cast(uint)buf.sizeof);
			if (catchError!"read()"(nread))
			{
				if (m_error == EPosix.EWOULDBLOCK || m_error == EPosix.EAGAIN) 
					m_status.code = Status.ASYNC;
				return 0;
			}
			assert(nread > 0);
		

			/// starts (recursively) watching all newly created folders in a recursive entry,
			/// creates events for additional files/folders founds, and unwatches all deleted folders
			void recurseInto(DWFolderInfo fi, DWFileEvent ev, ref Array!DWChangeInfo changes) {
				import std.file : dirEntries, SpanMode, isDir;
				assert(fi.wi.recursive);
				// get a list of stuff in the created/moved folder
				if (ev == DWFileEvent.CREATED || ev == DWFileEvent.MOVED_TO) {
					foreach (de; dirEntries(fi.wi.path.toNativeString(), SpanMode.shallow)) {
						Path entryPath = fi.wi.path ~ Path(de.name);
						
						if (fi.wi.recursive && isDir(entryPath.toNativeString())) {
							
							watch(fd, WatchInfo(fi.wi.events, entryPath, fi.wi.recursive, 0) );
							void genEvents(Path subpath) {
								foreach (de; dirEntries(subpath.toNativeString(), SpanMode.shallow)) {
									auto subsubpath = subpath ~ Path(de.name);
									changes.insertBack(DWChangeInfo(DWFileEvent.CREATED, subsubpath));
									if (isDir(subsubpath.toNativeString()))
										genEvents(subsubpath);
								}
							}
							
							genEvents(entryPath);
							
						}
					}
				}
			}

			size_t i;
			do
			{
				for (auto p = buf.ptr; p < buf.ptr + nread; )
				{
					inotify_event* ev = cast(inotify_event*)p;
					p += inotify_event.sizeof + ev.len;

					DWFileEvent evtype;
					evtype = DWFileEvent.CREATED;
					if (ev.mask & IN_CREATE)
						evtype = DWFileEvent.CREATED;
					if (ev.mask & IN_DELETE || ev.mask & IN_DELETE_SELF)
						evtype = DWFileEvent.DELETED;
					if (ev.mask & IN_MOVED_FROM || ev.mask & IN_MOVE_SELF)
						evtype = DWFileEvent.MOVED_FROM;
					if (ev.mask & (IN_MOVED_TO))
						evtype = DWFileEvent.MOVED_TO;
					if (ev.mask & IN_MODIFY)
						evtype = DWFileEvent.MODIFIED;

					import std.path : buildPath;
					import core.stdc.string : strlen;
					string name = cast(string) ev.name.ptr[0 .. cast(size_t) ev.name.ptr.strlen].idup;
					DWFolderInfo fi;
					Path path;
					try {
						fi = m_dwFolders.get(tuple(cast(fd_t)fd,cast(uint)ev.wd), DWFolderInfo.init);
						if (fi == DWFolderInfo.init) {
							setInternalError!"m_dwFolders[ev.wd]"(Status.ERROR, "Could not retrieve wd index in folders: " ~ ev.wd.to!string); 
							continue;
						}
						path = fi.wi.path ~ Path(name); 
					}
					catch (Exception e) { 
						setInternalError!"m_dwFolders[ev.wd]"(Status.ERROR, "Could not retrieve wd index in folders"); 
						return 0; 
					}

					dst[i] = DWChangeInfo(evtype, path);
					import std.file : isDir;
					bool is_dir;
					try is_dir = isDir(path.toNativeString()); catch {}
					if (fi.wi.recursive && is_dir) {

						try {
							Array!DWChangeInfo changes;
							recurseInto(fi, evtype, changes);
							// stop watching if the folder was deleted
							if (evtype == DWFileEvent.DELETED || evtype == DWFileEvent.MOVED_FROM) {
								unwatch(fi.fd, fi.wi.wd);
							}
							foreach (change; changes[]) {
								i++;
								if (dst.length <= i)
									dst ~= change;
								else dst[i] = change;
							}
						}
						catch (Exception e) {
							setInternalError!"recurseInto"(Status.ERROR, "Failed to watch/unwatch contents of folder recursively."); 
							return 0; 
						}

					}


					i++;
					if (i >= dst.length)
						return cast(uint) i;
				}
				static if (LOG) foreach (j; 0 .. i) {
					try log("Change occured for FD#" ~ fd.to!string ~ ": " ~ dst[j].to!string); catch {}
				}
				nread = read(fd, buf.ptr, buf.sizeof);
				if (catchError!"read()"(nread)) {
					if (m_error == EPosix.EWOULDBLOCK || m_error == EPosix.EAGAIN)
						m_status.code = Status.ASYNC;
					return cast(uint) i;
				}
			} while (nread > 0);

			return cast(uint) i;
		}
		else /* if KQUEUE */ {
			Array!(DWChangeInfo)* changes;
			size_t i;
			try {
				changes = m_changes[fd];
				import std.algorithm : min;
				size_t cnt = min(dst.length, changes.length);
				foreach (DWChangeInfo change; (*changes)[0 .. cnt]) {
					dst[i] = (*changes)[i];
					i++;
				}
				changes.linearRemove((*changes)[0 .. cnt]);
			}
			catch (Exception e) {
				setInternalError!"watcher.readChanges"(Status.ERROR, "Could not read directory changes: " ~ e.msg);
				return false;
			}
			return cast(uint) i;
		}
	}

	bool broadcast(in fd_t fd, bool b) {
		m_status = StatusInfo.init;

		import libasync.internals.socket_compat : socklen_t, setsockopt, SO_BROADCAST, SOL_SOCKET;

		int val = b?1:0;
		socklen_t len = val.sizeof;
		int err = setsockopt(fd, SOL_SOCKET, SO_BROADCAST, &val, len);
		if (catchError!"setsockopt"(err))
			return false;

		return true;
	}

	private bool closeRemoteSocket(fd_t fd, bool forced) {
		
		int err;
		log("shutdown");
		import libasync.internals.socket_compat : shutdown, SHUT_WR, SHUT_RDWR, SHUT_RD;
		if (forced) 
			err = shutdown(fd, SHUT_RDWR);
		else
			err = shutdown(fd, SHUT_WR);

		static if (!EPOLL) {
			kevent_t[2] events;
			try log("!!DISC delete events"); catch {}
			EV_SET(&(events[0]), fd, EVFILT_READ, EV_DELETE | EV_DISABLE, 0, 0, null);
			EV_SET(&(events[1]), fd, EVFILT_WRITE, EV_DELETE | EV_DISABLE, 0, 0, null);
			kevent(m_kqueuefd, &(events[0]), 2, null, 0, null);

		}

		if (catchError!"shutdown"(err))
			return false;

		return true;
	}

	// for connected sockets
	bool closeSocket(fd_t fd, bool connected, bool forced = false)
	{
		log("closeSocket");
		if (connected && !closeRemoteSocket(fd, forced) && !forced)
			return false;
		
		if (!connected || forced) {
			// todo: flush the socket here?

			import core.sys.posix.unistd : close;
			log("close");
			int err = close(fd);
			if (catchError!"closesocket"(err)) 
				return false;
		}
		return true;
	}

	
	NetworkAddress getAddressFromIP(in string ipAddr, in ushort port = 0, in bool ipv6 = false, in bool tcp = true) 
	in {
		debug import libasync.internals.validator : validateIPv4, validateIPv6;
		debug assert(validateIPv4(ipAddr) || validateIPv6(ipAddr), "Trying to connect to an invalid IP address");
	}
	body {
		import libasync.internals.socket_compat : addrinfo, AI_NUMERICHOST, AI_NUMERICSERV;
		addrinfo hints;
		hints.ai_flags |= AI_NUMERICHOST | AI_NUMERICSERV; // Specific to an IP resolver!

		return getAddressInfo(ipAddr, port, ipv6, tcp, hints);
	}


	NetworkAddress getAddressFromDNS(in string host, in ushort port = 0, in bool ipv6 = true, in bool tcp = true)
	/*in { 
		debug import libasync.internals.validator : validateHost;
		debug assert(validateHost(host), "Trying to connect to an invalid domain"); 
	}
	body */{
		import libasync.internals.socket_compat : addrinfo;
		addrinfo hints;
		return getAddressInfo(host, port, ipv6, tcp, hints);
	}
	
	void setInternalError(string TRACE)(in Status s, in string details = "", in error_t error = EPosix.EACCES)
	{
		if (details.length > 0)
			m_status.text = TRACE ~ ": " ~ details;
		else m_status.text = TRACE;
		m_error = error;
		m_status.code = s;
		static if(LOG) log(m_status);
	}
private:	

	/// For DirectoryWatcher
	/// In kqueue/vnode, all we get is the folder in which changes occured.
	/// We have to figure out what changed exactly and put the results in a container 
	/// for the readChanges call.
	static if (!EPOLL) bool compareFolderFiles(DWFolderInfo fi, DWFileEvent events) {
		import std.file;
		import std.path : buildPath;
		try {
			Array!Path currFiles;
			auto wd = fi.wi.wd;
			auto path = fi.wi.path;
			auto fd = fi.fd;
			Array!(DWChangeInfo)* changes = m_changes.get(fd, null);
			assert(changes !is null, "Invalid wd, could not find changes array.");
			//import std.stdio : writeln;
			//writeln("Scanning path: ", path.toNativeString());
			//writeln("m_dwFiles length: ", m_dwFiles.length);
		
			// get a list of the folder
			foreach (de; dirEntries(path.toNativeString(), SpanMode.shallow)) {
				//writeln(de.name);
				Path entryPath = Path(de.name);
				if (!entryPath.absolute)
					entryPath = path ~ entryPath;
				bool found;

				// compare it to the cached list fixme: make it faster using another container?
				foreach (ref const fd_t id, ref const DWFileInfo file; m_dwFiles) {
					if (file.folder != wd) continue; // this file isn't in the evented folder
					if (file.path == entryPath) {
						found = true;
						log("File modified? " ~ entryPath.toNativeString() ~ " at: " ~ de.timeLastModified.to!string ~ " vs: " ~ file.lastModified.to!string);
						// Check if it was modified
						if (!isDir(entryPath.toNativeString()) && de.timeLastModified > file.lastModified)
						{
							DWFileInfo dwf = file;
							dwf.lastModified = de.timeLastModified;
							m_dwFiles[id] = dwf;
							changes.insertBack(DWChangeInfo(DWFileEvent.MODIFIED, file.path));
						}
						break;
					}
				}

				// This file/folder is new in the folder
				if (!found) {
					changes.insertBack(DWChangeInfo(DWFileEvent.CREATED, entryPath));

					if (fi.wi.recursive && isDir(entryPath.toNativeString())) {
						/// This is the complicated part. The folder needs to be watched, and all the events
						/// generated for every file/folder found recursively inside it,
						/// Useful e.g. when mkdir -p is used.
						watch(fd, WatchInfo(fi.wi.events, entryPath, fi.wi.recursive, wd) );
						void genEvents(Path subpath) {
							foreach (de; dirEntries(subpath.toNativeString(), SpanMode.shallow)) {
								auto subsubpath = Path(de.name);
								if (!subsubpath.absolute())
									subsubpath = subpath ~ subsubpath;
								changes.insertBack(DWChangeInfo(DWFileEvent.CREATED, subsubpath));
								if (isDir(subsubpath.toNativeString()))
									genEvents(subsubpath);
							}
						}

						genEvents(entryPath);

					}
					else {
						EventInfo* evinfo;
						try evinfo = m_watchers[fd]; catch { assert(false, "Could retrieve event info, directory watcher was not initialized properly, or you are operating on a closed directory watcher."); }

						log("Adding path: " ~ path.toNativeString());

						import core.sys.posix.fcntl : open;
						fd_t fwd = open(entryPath.toNativeString().toStringz, O_EVTONLY);
						if (catchError!"open(watch)"(fwd))
							return 0;

						kevent_t _event;
						
						EV_SET(&_event, fwd, EVFILT_VNODE, EV_ADD | EV_CLEAR, fi.wi.events, 0, cast(void*) evinfo);
						
						int err = kevent(m_kqueuefd, &_event, 1, null, 0, null);

						if (catchError!"kevent_timer_add"(err))
							return 0;

						m_dwFiles[fwd] = DWFileInfo(fi.wi.wd, entryPath, de.timeLastModified, false);
						
					}
				}

				// This file/folder is now current. This avoids a deletion event.
				currFiles.insert(entryPath);
			}

			/// Now search for files/folders that were deleted in this directory (no recursivity needed). 
			/// Unwatch this directory and generate delete event only for the root dir
			foreach (ref const fd_t id, ref const DWFileInfo file; m_dwFiles) {
				if (file.folder != wd) continue; // skip those files in another folder than the evented one
				bool found;
				foreach (Path curr; currFiles) {
					if (file.path == curr){
						found = true;
						break;
					}
				}
				// this file/folder was in the folder but it's not there anymore
				if (!found) {
					// writeln("Deleting: ", file.path.toNativeString());
					kevent_t _event;
					EV_SET(&_event, cast(int) id, EVFILT_VNODE, EV_DELETE, 0, 0, null);
					int err = kevent(m_kqueuefd, &_event, 1, null, 0, null);
					if (catchError!"kevent_unwatch"(err))
						return false;
					import core.sys.posix.unistd : close;
					err = close(id);
					if (catchError!"close(dwFile)"(err))
						return false;
					changes.insert(DWChangeInfo(DWFileEvent.DELETED, file.path));

					if (fi.wi.recursive && file.is_dir) 
						unwatch(fd, id);

					m_dwFiles.remove(id);

				}
				
			}
			if(changes.empty)
				return false; // unhandled event, skip the callback

			// fixme: how to implement moved_from moved_to for rename?
		}
		catch (Exception e) 
		{
			try setInternalError!"compareFiles"(Status.ERROR, "Fatal error in file comparison: " ~ e.toString()); catch {}
			return false;
		}
		return true;
	}

	// socket must not be connected
	bool setNonBlock(fd_t fd) {
		import core.sys.posix.fcntl : fcntl, F_GETFL, F_SETFL, O_NONBLOCK;
		int flags = fcntl(fd, F_GETFL);
		flags |= O_NONBLOCK;
		int err = fcntl(fd, F_SETFL, flags);
		if (catchError!"F_SETFL O_NONBLOCK"(err)) {
			closeSocket(fd, false);
			return false;
		}
		return true;
	}
	
	bool onTCPAccept(fd_t fd, TCPAcceptHandler del, int events)
	{
		import libasync.internals.socket_compat : AF_INET, AF_INET6, socklen_t, accept4, accept;
		enum O_NONBLOCK     = 0x800;    // octal    04000

		static if (EPOLL) 
		{
			const uint epoll_events = cast(uint) events;
			const bool incoming = cast(bool) (epoll_events & EPOLLIN);
			const bool error = cast(bool) (epoll_events & EPOLLERR);
		}
		else 
		{
			const short kqueue_events = cast(short) (events >> 16);
			const ushort kqueue_flags = cast(ushort) (events & 0xffff);
			const bool incoming = cast(bool)(kqueue_events & EVFILT_READ);
			const bool error = cast(bool)(kqueue_flags & EV_ERROR);
		}
		
		if (incoming) { // accept incoming connection
			do {
				NetworkAddress addr;
				addr.family = AF_INET;
				socklen_t addrlen = addr.sockAddrLen;

				bool ret;
				static if (EPOLL) {
					/// Accept the connection and create a client socket
					fd_t csock = accept4(fd, addr.sockAddr, &addrlen, O_NONBLOCK);

					if (catchError!".accept"(csock)) {
						ret = false;
						return ret;
					}
				} else /* if KQUEUE */ {
					fd_t csock = accept(fd, addr.sockAddr, &addrlen);
					
					if (catchError!".accept"(csock)) {
						ret = false;
						return ret;
					}
					
					// Make non-blocking so subsequent calls to recv/send return immediately
					if (!setNonBlock(csock)) {
						ret = false;
						return ret;
					}
				}

				// Set client address family based on address length
				if (addrlen > addr.sockAddrLen)
					addr.family = AF_INET6;
				if (addrlen == socklen_t.init) {
					setInternalError!"addrlen"(Status.ABORT);
					import core.sys.posix.unistd : close;
					close(csock);
					{
						ret = false;
						return ret;
					}
				}

				// Allocate a new connection handler object
				AsyncTCPConnection conn;
				try conn = FreeListObjectAlloc!AsyncTCPConnection.alloc(m_evLoop);
				catch (Exception e){ assert(false, "Allocation failure"); }
				conn.peer = addr;
				conn.socket = csock;
				conn.inbound = true;

				nothrow bool closeClient() {
					try FreeListObjectAlloc!AsyncTCPConnection.free(conn);
					catch (Exception e){ assert(false, "Free failure"); }
					closeSocket(csock, true, true);
					{
						ret = false;
						return ret;
					}
				}

				// Get the connection handler from the callback
				TCPEventHandler evh;
				try {
					evh = del(conn);
					if (evh == TCPEventHandler.init || !initTCPConnection(csock, conn, evh, true)) {
						try log("Failed to connect"); catch {}
						return closeClient();
					}
					try log("Connection Started with " ~ csock.to!string); catch {}
				}
				catch (Exception e) {
					log("Close socket");
					return closeClient();
				}

				// Announce connection state to the connection handler
				try {
					log("Connected to: " ~ addr.toString());
					evh.conn.connected = true;
					evh(TCPEvent.CONNECT);
				}
				catch (Exception e) {
					setInternalError!"del@TCPEvent.CONNECT"(Status.ABORT);
					{
						ret = false;
						return ret;
					}
				}
			} while(true);

		}
		
		if (error) { // socket failure
			m_status.text = "listen socket error";
			int err;
			import libasync.internals.socket_compat : getsockopt, socklen_t, SOL_SOCKET, SO_ERROR;
			socklen_t len = int.sizeof;
			getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &len);
			m_error = cast(error_t) err;
			m_status.code = Status.ABORT;
			static if(LOG) log(m_status);

			// call with null to announce a failure
			try del(null);
			catch(Exception e){ assert(false, "Failure calling TCPAcceptHandler(null)"); }

			/// close the listener?
			// closeSocket(fd, false);
		}
		return true;
	}

	bool onUDPTraffic(fd_t fd, UDPHandler del, int events) 
	{
		static if (EPOLL) 
		{
			const uint epoll_events = cast(uint) events;
			const bool read = cast(bool) (epoll_events & EPOLLIN);
			const bool write = cast(bool) (epoll_events & EPOLLOUT);
			const bool error = cast(bool) (epoll_events & EPOLLERR);
		}
		else 
		{
			const short kqueue_events = cast(short) (events >> 16);
			const ushort kqueue_flags = cast(ushort) (events & 0xffff);
			const bool read = cast(bool) (kqueue_events & EVFILT_READ);
			const bool write = cast(bool) (kqueue_events & EVFILT_WRITE);
			const bool error = cast(bool) (kqueue_flags & EV_ERROR);
		}

		if (read) {
			try {
				del(UDPEvent.READ);
			}
			catch (Exception e) {
				setInternalError!"del@UDPEvent.READ"(Status.ABORT);
				return false;
			}
		}

		if (write) { 

			try {
				del(UDPEvent.WRITE);
			}
			catch (Exception e) {
				setInternalError!"del@UDPEvent.WRITE"(Status.ABORT);
				return false;
			}
		}

		if (error) // socket failure
		{ 

			import libasync.internals.socket_compat : socklen_t, getsockopt, SOL_SOCKET, SO_ERROR;
			import core.sys.posix.unistd : close;
			int err;
			socklen_t errlen = err.sizeof;
			getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &errlen);
			setInternalError!"EPOLLERR"(Status.ABORT, null, cast(error_t)err);
			close(fd);
		}
		
		return true;
	}

	bool onTCPTraffic(fd_t fd, TCPEventHandler del, int events, AsyncTCPConnection conn) 
	{
		log("TCP Traffic at FD#" ~ fd.to!string);

		static if (EPOLL) 
		{
			const uint epoll_events = cast(uint) events;
			const bool connect = ((cast(bool) (epoll_events & EPOLLIN)) || (cast(bool) (epoll_events & EPOLLOUT))) && !conn.disconnecting && !conn.connected;
			bool read = cast(bool) (epoll_events & EPOLLIN);
			const bool write = cast(bool) (epoll_events & EPOLLOUT);
			const bool error = cast(bool) (epoll_events & EPOLLERR);
			const bool close = (cast(bool) (epoll_events & EPOLLRDHUP)) || (cast(bool) (events & EPOLLHUP));
		}
		else /* if KQUEUE */
		{
			const short kqueue_events = cast(short) (events >> 16);
			const ushort kqueue_flags = cast(ushort) (events & 0xffff);
			const bool connect = cast(bool) ((kqueue_events & EVFILT_READ || kqueue_events & EVFILT_WRITE) && !conn.disconnecting && !conn.connected);
			bool read = cast(bool) (kqueue_events & EVFILT_READ) && !connect;
			const bool write = cast(bool) (kqueue_events & EVFILT_WRITE);
			const bool error = cast(bool) (kqueue_flags & EV_ERROR);
			const bool close = cast(bool) (kqueue_flags & EV_EOF);
		}

		if (error) 
		{
			import libasync.internals.socket_compat : socklen_t, getsockopt, SOL_SOCKET, SO_ERROR;
			int err;
			try log("Also got events: " ~ connect.to!string ~ " c " ~ read.to!string ~ " r " ~ write.to!string ~ " write"); catch {}
			socklen_t errlen = err.sizeof;
			getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &errlen);
			setInternalError!"EPOLLERR"(Status.ABORT, null, cast(error_t)err);
			try 
				del(TCPEvent.ERROR);
			catch (Exception e)
			{ 
				setInternalError!"del@TCPEvent.ERROR"(Status.ABORT);
				// ignore failure...
			}
			return false;
		}

		
		if (connect) 
		{
			try log("!connect"); catch {}
			conn.connected = true;
			try del(TCPEvent.CONNECT);
			catch (Exception e) {
				setInternalError!"del@TCPEvent.CONNECT"(Status.ABORT);
				return false;
			}
			return true;
		}


		if (write && conn.connected && !conn.disconnecting && conn.writeBlocked) 
		{
			conn.writeBlocked = false;
			try log("!write"); catch {}
			try del(TCPEvent.WRITE);
			catch (Exception e) {
				setInternalError!"del@TCPEvent.WRITE"(Status.ABORT);
				return false;
			}
		}
		else {
			read = true;
		}

		if (read && conn.connected && !conn.disconnecting)
		{
			try log("!read"); catch {}
			try del(TCPEvent.READ);
			catch (Exception e) {
				setInternalError!"del@TCPEvent.READ"(Status.ABORT);
				return false;
			}
		}

		if (close && conn.connected && !conn.disconnecting) 
		{
			try log("!close"); catch {}
			// todo: See if this hack is still necessary
			if (!conn.connected && conn.disconnecting)
				return true;
			
			try del(TCPEvent.CLOSE);
			catch (Exception e) {
				setInternalError!"del@TCPEvent.CLOSE"(Status.ABORT);
				return false;
			}
			closeSocket(fd, !conn.disconnecting, conn.connected);
			
			m_status.code = Status.ABORT;
			conn.disconnecting = true;
			conn.connected = false;
			conn.writeBlocked = true;
			del.conn.socket = 0;
			
			try FreeListObjectAlloc!EventInfo.free(del.conn.evInfo);
			catch (Exception e){ assert(false, "Error freeing resources"); }
			
			if (del.conn.inbound) {
				log("Freeing inbound connection");
				try FreeListObjectAlloc!AsyncTCPConnection.free(del.conn);
				catch (Exception e){ assert(false, "Error freeing resources"); }
			}
		}
		return true;
	}
	
	bool initUDPSocket(fd_t fd, AsyncUDPSocket ctxt, UDPHandler del)
	{
		import libasync.internals.socket_compat : bind;
		import core.sys.posix.unistd;

		fd_t err;

		EventObject eo;
		eo.udpHandler = del;
		EventInfo* ev;
		try ev = FreeListObjectAlloc!EventInfo.alloc(fd, EventType.UDPSocket, eo, m_instanceId);
		catch (Exception e){ assert(false, "Allocation error"); }
		ctxt.evInfo = ev;
		nothrow bool closeAll() {
			try FreeListObjectAlloc!EventInfo.free(ev);
			catch(Exception e){ assert(false, "Failed to free resources"); }
			ctxt.evInfo = null;
			// socket will be closed by caller if return false
			return false;
		}

		static if (EPOLL)
		{
			epoll_event _event;
			_event.data.ptr = ev;
			_event.events = EPOLLIN | EPOLLOUT | EPOLLET;
			err = epoll_ctl(m_epollfd, EPOLL_CTL_ADD, fd, &_event);
			if (catchError!"epoll_ctl"(err)) {
				return closeAll();
			}
			nothrow void deregisterEvent() {}
		}
		else /* if KQUEUE */
		{
			kevent_t[2] _event;
			EV_SET(&(_event[0]), fd, EVFILT_READ, EV_ADD | EV_ENABLE, 0, 0, ev);
			EV_SET(&(_event[1]), fd, EVFILT_WRITE, EV_ADD | EV_ENABLE, 0, 0, ev);
			err = kevent(m_kqueuefd, &(_event[0]), 2, null, 0, null);
			if (catchError!"kevent_add_udp"(err))
				return closeAll();
			
			nothrow void deregisterEvent() {
				EV_SET(&(_event[0]), fd, EVFILT_READ, EV_DELETE | EV_DISABLE, 0, 0, null);
				EV_SET(&(_event[1]), fd, EVFILT_WRITE, EV_DELETE | EV_DISABLE, 0, 0, null);
				kevent(m_kqueuefd, &(_event[0]), 2, null, 0, cast(libasync.internals.kqueue.timespec*) null);
			}

		}

		/// Start accepting packets
		err = bind(fd, ctxt.local.sockAddr, ctxt.local.sockAddrLen);
		if (catchError!"bind"(err)) {
			deregisterEvent();
			return closeAll();
		}

		return true;
	}


	bool initTCPListener(fd_t fd, AsyncTCPListener ctxt, TCPAcceptHandler del, bool reusing = false)
	in {
		assert(ctxt.local !is NetworkAddress.init);
	}
	body {
		import libasync.internals.socket_compat : bind, listen, SOMAXCONN;
		fd_t err;

		/// Create callback object
		EventObject eo;
		eo.tcpAcceptHandler = del;
		EventInfo* ev;

		try ev = FreeListObjectAlloc!EventInfo.alloc(fd, EventType.TCPAccept, eo, m_instanceId);
		catch (Exception e){ assert(false, "Allocation error"); }
		ctxt.evInfo = ev;
		nothrow bool closeAll() {
			try FreeListObjectAlloc!EventInfo.free(ev);
			catch(Exception e){ assert(false, "Failed free"); }
			ctxt.evInfo = null;
			// Socket is closed by run()
			//closeSocket(fd, false);
			return false;
		}

		/// Add socket to event loop
		static if (EPOLL)
		{
			epoll_event _event;
			_event.data.ptr = ev;
			_event.events = EPOLLIN | EPOLLET;
			err = epoll_ctl(m_epollfd, EPOLL_CTL_ADD, fd, &_event);
			if (catchError!"epoll_ctl_add"(err))
				return closeAll();

			nothrow void deregisterEvent() {
				// epoll cleans itself when closing the socket
			}
		}
		else /* if KQUEUE */
		{
			kevent_t _event;
			EV_SET(&_event, fd, EVFILT_READ, EV_ADD | EV_ENABLE, 0, 0, ev);
			err = kevent(m_kqueuefd, &_event, 1, null, 0, null);
			if (catchError!"kevent_add_listener"(err))
				return closeAll();

			nothrow void deregisterEvent() {
				EV_SET(&_event, fd, EVFILT_READ, EV_CLEAR | EV_DISABLE, 0, 0, null);
				kevent(m_kqueuefd, &_event, 1, null, 0, null);
				// wouldn't know how to deal with errors here...
			}
		}

		/// Bind and listen to socket
		if (!reusing) {
			err = bind(fd, ctxt.local.sockAddr, ctxt.local.sockAddrLen);
			if (catchError!"bind"(err)) {
				deregisterEvent();
				return closeAll();
			}

			err = listen(fd, SOMAXCONN);
			if (catchError!"listen"(err)) {
				deregisterEvent();
				return closeAll();
			}

		}
		return true;
	}

	bool initTCPConnection(fd_t fd, AsyncTCPConnection ctxt, TCPEventHandler del, bool inbound = false)
	in { 
		assert(ctxt.peer.port != 0, "Connecting to an invalid port");
	}
	body {

		fd_t err;

		/// Create callback object
		import libasync.internals.socket_compat : connect;
		EventObject eo;
		eo.tcpEvHandler = del;
		EventInfo* ev;

		try ev = FreeListObjectAlloc!EventInfo.alloc(fd, EventType.TCPTraffic, eo, m_instanceId);
		catch (Exception e){ assert(false, "Allocation error"); }
		assert(ev !is null);
		ctxt.evInfo = ev;
		nothrow bool destroyEvInfo() {
			try FreeListObjectAlloc!EventInfo.free(ev);
			catch(Exception e){ assert(false, "Failed to free resources"); }
			ctxt.evInfo = null;

			// Socket will be closed by run()
			// closeSocket(fd, false);
			return false;
		}

		/// Add socket and callback object to event loop
		static if (EPOLL)
		{
			epoll_event _event = void;
			_event.data.ptr = ev;
			_event.events = 0 | EPOLLIN | EPOLLOUT | EPOLLERR | EPOLLHUP | EPOLLRDHUP | EPOLLET;
			err = epoll_ctl(m_epollfd, EPOLL_CTL_ADD, fd, &_event);
			log("Connection FD#" ~ fd.to!string ~ " added to " ~ m_epollfd.to!string);
			if (catchError!"epoll_ctl_add"(err))
				return destroyEvInfo();

			nothrow void deregisterEvent() {
				// will be handled automatically when socket is closed
			}
		}
		else /* if KQUEUE */
		{
			kevent_t[2] events = void;
			try log("Register event ptr " ~ ev.to!string); catch {}
			assert(ev.evType == EventType.TCPTraffic, "Bad event type for TCP Connection");
			EV_SET(&(events[0]), fd, EVFILT_READ, EV_ADD | EV_ENABLE | EV_CLEAR, 0, 0, cast(void*) ev);
			EV_SET(&(events[1]), fd, EVFILT_WRITE, EV_ADD | EV_ENABLE | EV_CLEAR, 0, 0, cast(void*) ev);
			assert((cast(EventInfo*)events[0].udata) == ev && (cast(EventInfo*)events[1].udata) == ev);
			assert((cast(EventInfo*)events[0].udata).owner == m_instanceId && (cast(EventInfo*)events[1].udata).owner == m_instanceId);
			err = kevent(m_kqueuefd, &(events[0]), 2, null, 0, null);
			if (catchError!"kevent_add_tcp"(err))
				return destroyEvInfo();

			// todo: verify if this allocates on the GC?
			nothrow void deregisterEvent() {
				EV_SET(&(events[0]), fd, EVFILT_READ, EV_DELETE | EV_DISABLE, 0, 0, null);
				EV_SET(&(events[1]), fd, EVFILT_WRITE, EV_DELETE | EV_DISABLE, 0, 0, null);
				kevent(m_kqueuefd, &(events[0]), 2, null, 0, null);
				// wouldn't know how to deal with errors here...
			}
		}

		// Inbound objects are already connected
		if (inbound) return true;

		// Connect is blocking, but this makes the socket non-blocking for send/recv
		if (!setNonBlock(fd)) {
			deregisterEvent();
			return destroyEvInfo();
		}

		/// Start the connection
		err = connect(fd, ctxt.peer.sockAddr, ctxt.peer.sockAddrLen);
		if (catchErrorsEq!"connect"(err, [ tuple(cast(fd_t)SOCKET_ERROR, EPosix.EINPROGRESS, Status.ASYNC) ]))
			return true;
		if (catchError!"connect"(err)) {
			deregisterEvent();
			return destroyEvInfo();
		}

		return true;
	}

	bool catchError(string TRACE, T)(T val, T cmp = SOCKET_ERROR)
		if (isIntegral!T)
	{
		if (val == cmp) {
			m_status.text = TRACE;
			m_error = lastError();
			m_status.code = Status.ABORT;
			static if(LOG) log(m_status);
			return true;
		}
		return false;
	}

	bool catchSocketError(string TRACE)(fd_t fd)
	{
		m_status.text = TRACE;
		int err;
		import libasync.internals.socket_compat : getsockopt, socklen_t, SOL_SOCKET, SO_ERROR;
		socklen_t len = int.sizeof;
		getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &len);
		m_error = cast(error_t) err;
		if (m_error != EPosix.EOK) {
			m_status.code = Status.ABORT;
			static if(LOG) log(m_status);
			return true;
		}

		return false;
	}

	bool catchEvLoopErrors(string TRACE, T)(T val, Tuple!(T, Status)[] cmp ...)
		if (isIntegral!T)
	{
		if (val == SOCKET_ERROR) {
			int err = errno;
			foreach (validator ; cmp) {
				if (errno == validator[0]) {
					m_status.text = TRACE;
					m_error = lastError();
					m_status.code = validator[1];
					static if(LOG) log(m_status);
					return true;
				}
			}

			m_status.text = TRACE;
			m_status.code = Status.EVLOOP_FAILURE;
			m_error = lastError();
			log(m_status);
			return true;
		}
		return false;
	}

	/**
	 * If the value at val matches the tuple first argument T, get the last error,
	 * and if the last error matches tuple second argument error_t, set the Status as
	 * tuple third argument Status.
	 * 
	 * Repeats for each comparison tuple until a match in which case returns true.
	*/
	bool catchErrorsEq(string TRACE, T)(T val, Tuple!(T, error_t, Status)[] cmp ...)
		if (isIntegral!T)
	{
		error_t err;
		foreach (validator ; cmp) {
			if (val == validator[0]) {
				if (err is EPosix.init) err = lastError();
				if (err == validator[1]) {
					m_status.text = TRACE;
					m_status.code = validator[2];
					if (m_status.code == Status.EVLOOP_TIMEOUT) {
						log(m_status);
						break;
					}
					m_error = lastError();
					static if(LOG) log(m_status);
					return true;
				}
			}
		}
		return false;
	}


	error_t lastError() {
		try {
			return cast(error_t) errno;
		} catch(Exception e) {
			return EPosix.EACCES;
		}

	}
	
	void log(StatusInfo val)
	{
		static if (LOG) {
			import std.stdio;
			try {
				writeln("Backtrace: ", m_status.text);
				writeln(" | Status:  ", m_status.code);
				writeln(" | Error: " , m_error);
				if ((m_error in EPosixMessages) !is null)
					writeln(" | Message: ", EPosixMessages[m_error]);
			} catch(Exception e) {
				return;
			}
		}
	}

	void log(T)(T val)
	{
		static if (LOG) {
			import std.stdio;
			try {
				writeln(val);
			} catch(Exception e) {
				return;
			}
		}
	}

	NetworkAddress getAddressInfo(addrinfo)(in string host, ushort port, bool ipv6, bool tcp, ref addrinfo hints) 
	{
		m_status = StatusInfo.init;
		import libasync.internals.socket_compat : AF_INET, AF_INET6, SOCK_DGRAM, SOCK_STREAM, IPPROTO_TCP, IPPROTO_UDP, freeaddrinfo, getaddrinfo;

		NetworkAddress addr;
		addrinfo* infos;
		error_t err;
		if (ipv6) {
			addr.family = AF_INET6;
			hints.ai_family = AF_INET6;
		}
		else {
			addr.family = AF_INET;
			hints.ai_family = AF_INET;
		}
		if (tcp) {
			hints.ai_socktype = SOCK_STREAM;
			hints.ai_protocol = IPPROTO_TCP;
		}
		else {
			hints.ai_socktype = SOCK_DGRAM;
			hints.ai_protocol = IPPROTO_UDP;
		}

		static if (LOG) {
			log("Resolving " ~ host ~ ":" ~ port.to!string);
		}

		auto chost = host.toStringz();

		if (port != 0) {
			addr.port = port;
			const(char)* cPort = cast(const(char)*) port.to!string.toStringz;
			err = cast(error_t) getaddrinfo(chost, cPort, &hints, &infos);
		}
		else {
			err = cast(error_t) getaddrinfo(chost, null, &hints, &infos);
		}

		if (err != EPosix.EOK) {
			setInternalError!"getAddressInfo"(Status.ERROR, string.init, err);
			return NetworkAddress.init;
		}
		ubyte* pAddr = cast(ubyte*) infos.ai_addr;
		ubyte* data = cast(ubyte*) addr.sockAddr;
		data[0 .. infos.ai_addrlen] = pAddr[0 .. infos.ai_addrlen]; // perform bit copy
		freeaddrinfo(infos);
		return addr;
	}


	
}


static if (!EPOLL)
{
	import std.container : Array;
	import core.sync.mutex : Mutex;
	import core.sync.rwmutex : ReadWriteMutex;
	size_t g_evIdxCapacity;
	Array!size_t g_evIdxAvailable;

	// called on run
	nothrow size_t createIndex() {
		size_t idx;
		import std.algorithm : max;
		try {
			
			size_t getIdx() {
				
				if (!g_evIdxAvailable.empty) {
					immutable size_t ret = g_evIdxAvailable.back;
					g_evIdxAvailable.removeBack();
					return ret;
				}
				return 0;
			}
			
			idx = getIdx();
			if (idx == 0) {
				import std.range : iota;
				g_evIdxAvailable.insert( iota(g_evIdxCapacity, max(32, g_evIdxCapacity * 2), 1) );
				g_evIdxCapacity = max(32, g_evIdxCapacity * 2);
				idx = getIdx();
			}
			
		} catch (Throwable e) {

			import std.stdio;
			
			try writeln(e.toString()); catch {}

		}
		return idx;
	}

	nothrow void destroyIndex(AsyncNotifier ctxt) {
		try {
			g_evIdxAvailable.insert(ctxt.id);		
		}
		catch (Exception e) {
			assert(false, "Error destroying index: " ~ e.msg);
		}
	}

	nothrow void destroyIndex(AsyncTimer ctxt) {
		try {
			g_evIdxAvailable.insert(ctxt.id);		
		}
		catch (Exception e) {
			assert(false, "Error destroying index: " ~ e.msg);
		}
	}

	size_t* g_threadId;
	size_t g_idxCapacity;
	Array!size_t g_idxAvailable;

	__gshared ReadWriteMutex gs_queueMutex;
	__gshared Array!(Array!AsyncSignal) gs_signalQueue;
	__gshared Array!(Array!size_t) gs_idxQueue; // signals notified


	// loop
	nothrow bool popSignals(ref AsyncSignal[] sigarr) {
		bool more;
		try {
			foreach (ref AsyncSignal sig; sigarr) {
				if (!sig)
					break;
				sig = null;
			}
			size_t len;
			synchronized(gs_queueMutex.reader) {

				if (gs_idxQueue.length <= *g_threadId || gs_idxQueue[*g_threadId].empty)
					return false;

				len = gs_idxQueue[*g_threadId].length;
				import std.stdio;
				if (sigarr.length < len) {
					more = true;
					len = sigarr.length;
				}

				size_t i;
				foreach (size_t idx; gs_idxQueue[*g_threadId][0 .. len]){
					sigarr[i] = gs_signalQueue[*g_threadId][idx];
					i++;
				}
			}

			synchronized (gs_queueMutex.writer) {
				gs_idxQueue[*g_threadId].linearRemove(gs_idxQueue[*g_threadId][0 .. len]);
			}
		}
		catch (Exception e) {
			assert(false, "Could not get pending signals: " ~ e.msg);
		}
		return more;
	}

	// notify
	nothrow void addSignal(shared AsyncSignal ctxt) {
		try {
			size_t thread_id = ctxt.threadId;
			bool must_resize;
			import std.stdio;
			synchronized (gs_queueMutex.writer) {
				if (gs_idxQueue.empty || gs_idxQueue.length < thread_id + 1) {
					gs_idxQueue.reserve(thread_id + 1);
					foreach (i; gs_idxQueue.length .. gs_idxQueue.capacity) {
						gs_idxQueue.insertBack(Array!size_t.init);
					}
				}
				if (gs_idxQueue[thread_id].empty)
				{
					gs_idxQueue[thread_id].reserve(32);
				}

				gs_idxQueue[thread_id].insertBack(ctxt.id);

			}

		}
		catch (Exception e) {
			assert(false, "Array error: " ~ e.msg);
		}
	}

	// called on run
	nothrow size_t createIndex(shared AsyncSignal ctxt) {
		size_t idx;
		import std.algorithm : max;
		try {
			bool must_resize;

			synchronized (gs_queueMutex.reader) {
				if (gs_signalQueue.length < *g_threadId)
					must_resize = true;
			}

			/// make sure the signal queue is big enough for this thread ID
			if (must_resize) {
				synchronized (gs_queueMutex.writer) {
					while (gs_signalQueue.length <= *g_threadId) 
						gs_signalQueue.insertBack(Array!AsyncSignal.init);
				}
			}

			size_t getIdx() {

				if (!g_idxAvailable.empty) {
					immutable size_t ret = g_idxAvailable.back;
					g_idxAvailable.removeBack();
					return ret;
				}
				return 0;
			}

			idx = getIdx();
			if (idx == 0) {
				import std.range : iota;
				g_idxAvailable.insert( iota(g_idxCapacity,  max(32, g_idxCapacity * 2), 1) );
				g_idxCapacity = max(32, g_idxCapacity * 2);
				idx = getIdx();
			}

			synchronized (gs_queueMutex.writer) {
				if (gs_signalQueue.empty || gs_signalQueue.length < *g_threadId + 1) {
					
					gs_signalQueue.reserve(*g_threadId + 1);
					foreach (i; gs_signalQueue.length .. gs_signalQueue.capacity) {
						gs_signalQueue.insertBack(Array!AsyncSignal.init);
					}
					
				}

				if (gs_signalQueue[*g_threadId].empty || gs_signalQueue[*g_threadId].length < idx + 1) {
					
					gs_signalQueue[*g_threadId].reserve(idx + 1);
					foreach (i; gs_signalQueue[*g_threadId].length .. gs_signalQueue[*g_threadId].capacity) {
						gs_signalQueue[*g_threadId].insertBack(cast(AsyncSignal)null);
					}
					
				}

				gs_signalQueue[*g_threadId][idx] = cast(AsyncSignal) ctxt;
			}
		} catch {}

		return idx;
	}

	// called on kill
	nothrow void destroyIndex(shared AsyncSignal ctxt) {
		try {
			g_idxAvailable.insert(ctxt.id);
			synchronized (gs_queueMutex.writer) {
				gs_signalQueue[*g_threadId][ctxt.id] = null;
			}
		}
		catch (Exception e) {
			assert(false, "Error destroying index: " ~ e.msg);
		}
	}
}

mixin template TCPConnectionMixins() {
	
	private CleanupData m_impl;
	
	struct CleanupData {
		EventInfo* evInfo;
		bool connected;
		bool disconnecting;
		bool writeBlocked;
	}
	
	@property bool disconnecting() const {
		return m_impl.disconnecting;
	}

	@property void disconnecting(bool b) {
		m_impl.disconnecting = b;
	}
	
	@property bool connected() const {
		return m_impl.connected;
	}

	@property void connected(bool b) {
		m_impl.connected = b;
	}

	@property bool writeBlocked() const {
		return m_impl.writeBlocked;
	}

	@property void writeBlocked(bool b) {
		m_impl.writeBlocked = b;
	}

	@property EventInfo* evInfo() {
		return m_impl.evInfo;
	}
	
	@property void evInfo(EventInfo* info) {
		m_impl.evInfo = info;
	}
	
}

mixin template EvInfoMixinsShared() {

	private CleanupData m_impl;
	
	shared struct CleanupData {
		EventInfo* evInfo;
	}

	static if (EPOLL) {
		import core.sys.posix.pthread : pthread_t;
		private pthread_t m_pthreadId;
		synchronized @property pthread_t pthreadId() {
			return cast(pthread_t) m_pthreadId;
		}
		/* todo: support multiple event loops per thread?
		private ushort m_sigId;
		synchronized @property ushort sigId() {
			return cast(ushort)m_loopId;
		}
		synchronized @property void sigId(ushort id) {
			m_loopId = cast(shared)id;
		}
		*/
	} 
	else /* if KQUEUE */
	{
		private shared(size_t)* m_owner_id;
		synchronized @property size_t threadId() {
			return cast(size_t) *m_owner_id;
		}
	}

	@property shared(EventInfo*) evInfo() {
		return m_impl.evInfo;
	}
	
	@property void evInfo(shared(EventInfo*) info) {
		m_impl.evInfo = info;
	}

}

mixin template EvInfoMixins() {
	
	private CleanupData m_impl;
	
	struct CleanupData {
		EventInfo* evInfo;
	}
	
	@property EventInfo* evInfo() {
		return m_impl.evInfo;
	}
	
	@property void evInfo(EventInfo* info) {
		m_impl.evInfo = info;
	}
}



union EventObject {
	TCPAcceptHandler tcpAcceptHandler;
	TCPEventHandler tcpEvHandler;
	TimerHandler timerHandler;
	DWHandler dwHandler;
	UDPHandler udpHandler;
	NotifierHandler notifierHandler;
}

enum EventType : char {
	TCPAccept,
	TCPTraffic,
	UDPSocket,
	Notifier,
	Signal,
	Timer,
	DirectoryWatcher
}

struct EventInfo {
	fd_t fd;
	EventType evType;
	EventObject evObj;
	ushort owner;
}



/**
		Represents a network/socket address. (taken from vibe.core.net)
*/
public struct NetworkAddress {
	import libasync.internals.socket_compat : sockaddr, sockaddr_in, sockaddr_in6, AF_INET, AF_INET6;
	private union {
		sockaddr addr;
		sockaddr_in addr_ip4;
		sockaddr_in6 addr_ip6;
	}

	@property bool ipv6() const pure nothrow { return this.family == AF_INET6; }

	/** Family (AF_) of the socket address.
		*/
	@property ushort family() const pure nothrow { return addr.sa_family; }
	/// ditto
	@property void family(ushort val) pure nothrow { addr.sa_family = cast(ubyte)val; }
	
	/** The port in host byte order.
		*/
	@property ushort port()
	const pure nothrow {
		switch (this.family) {
			default: assert(false, "port() called for invalid address family.");
			case AF_INET: return ntoh(addr_ip4.sin_port);
			case AF_INET6: return ntoh(addr_ip6.sin6_port);
		}
	}
	/// ditto
	@property void port(ushort val)
	pure nothrow {
		switch (this.family) {
			default: assert(false, "port() called for invalid address family.");
			case AF_INET: addr_ip4.sin_port = hton(val); break;
			case AF_INET6: addr_ip6.sin6_port = hton(val); break;
		}
	}
	
	/** A pointer to a sockaddr struct suitable for passing to socket functions.
		*/
	@property inout(sockaddr)* sockAddr() inout pure nothrow { return &addr; }
	
	/** Size of the sockaddr struct that is returned by sockAddr().
		*/
	@property uint sockAddrLen()
	const pure nothrow {
		switch (this.family) {
			default: assert(false, "sockAddrLen() called for invalid address family.");
			case AF_INET: return addr_ip4.sizeof;
			case AF_INET6: return addr_ip6.sizeof;
		}
	}
	
	@property inout(sockaddr_in)* sockAddrInet4() inout pure nothrow
	in { assert (family == AF_INET); }
	body { return &addr_ip4; }
	
	@property inout(sockaddr_in6)* sockAddrInet6() inout pure nothrow
	in { assert (family == AF_INET6); }
	body { return &addr_ip6; }
	
	/** Returns a string representation of the IP address
		*/
	string toAddressString()
	const {
		import std.array : appender;
		import std.string : format;
		import std.format : formattedWrite;
		
		switch (this.family) {
			default: assert(false, "toAddressString() called for invalid address family.");
			case AF_INET:
				ubyte[4] ip = (cast(ubyte*)&addr_ip4.sin_addr.s_addr)[0 .. 4];
				return format("%d.%d.%d.%d", ip[0], ip[1], ip[2], ip[3]);
			case AF_INET6:
				ubyte[16] ip = addr_ip6.sin6_addr.s6_addr;
				auto ret = appender!string();
				ret.reserve(40);
				foreach (i; 0 .. 8) {
					if (i > 0) ret.put(':');
					ret.formattedWrite("%x", bigEndianToNative!ushort(cast(ubyte[2])ip[i*2 .. i*2+2].ptr[0 .. 2]));
				}
				return ret.data;
		}
	}
	
	/** Returns a full string representation of the address, including the port number.
		*/
	string toString()
	const {
		
		import std.string : format;
		
		auto ret = toAddressString();
		switch (this.family) {
			default: assert(false, "toString() called for invalid address family.");
			case AF_INET: return ret ~ format(":%s", port);
			case AF_INET6: return format("[%s]:%s", ret, port);
		}
	}
	
}

private pure nothrow {
	import std.bitmanip;
	
	ushort ntoh(ushort val)
	{
		version (LittleEndian) return swapEndian(val);
		else version (BigEndian) return val;
		else static assert(false, "Unknown endianness.");
	}
	
	ushort hton(ushort val)
	{
		version (LittleEndian) return swapEndian(val);
		else version (BigEndian) return val;
		else static assert(false, "Unknown endianness.");
	}
}