Clean up SocketEngine interface to allow edge-triggered I/O and sockets that do not force readability.

git-svn-id: http://svn.inspircd.org/repository/trunk/inspircd@11760 e03df62e-2008-0410-955e-edbf42e46eb7

1 files changed, 65 insertions, 63 deletions

diff --git a/src/socketengines/socketengine_epoll.cpp b/src/socketengines/socketengine_epoll.cpp
index 7fed6f250..672ff4a7b 100644
--- a/src/socketengines/socketengine_epoll.cpp
+++ b/src/socketengines/socketengine_epoll.cpp
@@ -18,7 +18,18 @@
 
 EPollEngine::EPollEngine()
 {
-	MAX_DESCRIPTORS = 0;
+	int max = ulimit(4, 0);
+	if (max > 0)
+	{
+		MAX_DESCRIPTORS = max;
+	}
+	else
+	{
+		ServerInstance->Logs->Log("SOCKET", DEFAULT, "ERROR: Can't determine maximum number of open sockets!");
+		printf("ERROR: Can't determine maximum number of open sockets!\n");
+		ServerInstance->Exit(EXIT_STATUS_SOCKETENGINE);
+	}
+
 	// This is not a maximum, just a hint at the eventual number of sockets that may be polled.
 	EngineHandle = epoll_create(GetMaxFds() / 4);
 
@@ -26,11 +37,10 @@ EPollEngine::EPollEngine()
 	{
 		ServerInstance->Logs->Log("SOCKET",DEFAULT, "ERROR: Could not initialize socket engine: %s", strerror(errno));
 		ServerInstance->Logs->Log("SOCKET",DEFAULT, "ERROR: Your kernel probably does not have the proper features. This is a fatal error, exiting now.");
-		printf("ERROR: Could not initialize socket engine: %s\n", strerror(errno));
+		printf("ERROR: Could not initialize epoll socket engine: %s\n", strerror(errno));
 		printf("ERROR: Your kernel probably does not have the proper features. This is a fatal error, exiting now.\n");
 		ServerInstance->Exit(EXIT_STATUS_SOCKETENGINE);
 	}
-	CurrentSetSize = 0;
 
 	ref = new EventHandler* [GetMaxFds()];
 	events = new struct epoll_event[GetMaxFds()];
@@ -45,18 +55,35 @@ EPollEngine::~EPollEngine()
 	delete[] events;
 }
 
-bool EPollEngine::AddFd(EventHandler* eh, bool writeFirst)
+static int mask_to_epoll(int event_mask)
 {
-	int fd = eh->GetFd();
-	if ((fd < 0) || (fd > GetMaxFds() - 1))
+	int rv = 0;
+	if (event_mask & (FD_WANT_POLL_READ | FD_WANT_POLL_WRITE))
 	{
-		ServerInstance->Logs->Log("SOCKET",DEBUG,"AddFd out of range: (fd: %d, max: %d)", fd, GetMaxFds());
-		return false;
+		// we need to use standard polling on this FD
+		if (event_mask & (FD_WANT_POLL_READ | FD_WANT_FAST_READ))
+			rv |= EPOLLIN;
+		if (event_mask & (FD_WANT_POLL_WRITE | FD_WANT_FAST_WRITE))
+			rv |= EPOLLOUT;
 	}
+	else
+	{
+		// we can use edge-triggered polling on this FD
+		rv = EPOLLET;
+		if (event_mask & (FD_WANT_FAST_READ | FD_WANT_EDGE_READ))
+			rv |= EPOLLIN;
+		if (event_mask & (FD_WANT_FAST_WRITE | FD_WANT_EDGE_WRITE))
+			rv |= EPOLLOUT;
+	}
+	return rv;
+}
 
-	if (GetRemainingFds() <= 1)
+bool EPollEngine::AddFd(EventHandler* eh, int event_mask)
+{
+	int fd = eh->GetFd();
+	if ((fd < 0) || (fd > GetMaxFds() - 1))
 	{
-		ServerInstance->Logs->Log("SOCKET",DEBUG,"No remaining FDs cannot add fd: %d", fd);
+		ServerInstance->Logs->Log("SOCKET",DEBUG,"AddFd out of range: (fd: %d, max: %d)", fd, GetMaxFds());
 		return false;
 	}
 
@@ -68,7 +95,7 @@ bool EPollEngine::AddFd(EventHandler* eh, bool writeFirst)
 
 	struct epoll_event ev;
 	memset(&ev,0,sizeof(ev));
-	ev.events = writeFirst ? EPOLLOUT : EPOLLIN;
+	ev.events = mask_to_epoll(event_mask);
 	ev.data.fd = fd;
 	int i = epoll_ctl(EngineHandle, EPOLL_CTL_ADD, fd, &ev);
 	if (i < 0)
@@ -80,20 +107,24 @@ bool EPollEngine::AddFd(EventHandler* eh, bool writeFirst)
 	ServerInstance->Logs->Log("SOCKET",DEBUG,"New file descriptor: %d", fd);
 
 	ref[fd] = eh;
+	SocketEngine::SetEventMask(eh, event_mask);
 	CurrentSetSize++;
 	return true;
 }
 
-void EPollEngine::WantWrite(EventHandler* eh)
+void EPollEngine::OnSetEvent(EventHandler* eh, int old_mask, int new_mask)
 {
-	/** Use oneshot so that the system removes the writeable
-	 * status for us and saves us a call.
-	 */
-	struct epoll_event ev;
-	memset(&ev,0,sizeof(ev));
-	ev.events = EPOLLIN | EPOLLOUT;
-	ev.data.fd = eh->GetFd();
-	epoll_ctl(EngineHandle, EPOLL_CTL_MOD, eh->GetFd(), &ev);
+	int old_events = mask_to_epoll(old_mask);
+	int new_events = mask_to_epoll(new_mask);
+	if (old_events != new_events)
+	{
+		// ok, we actually have something to tell the kernel about
+		struct epoll_event ev;
+		memset(&ev,0,sizeof(ev));
+		ev.events = new_events;
+		ev.data.fd = eh->GetFd();
+		epoll_ctl(EngineHandle, EPOLL_CTL_MOD, eh->GetFd(), &ev);
+	}
 }
 
 bool EPollEngine::DelFd(EventHandler* eh, bool force)
@@ -117,37 +148,12 @@ bool EPollEngine::DelFd(EventHandler* eh, bool force)
 	}
 
 	ref[fd] = NULL;
-	CurrentSetSize--;
 
 	ServerInstance->Logs->Log("SOCKET",DEBUG,"Remove file descriptor: %d", fd);
+	CurrentSetSize--;
 	return true;
 }
 
-int EPollEngine::GetMaxFds()
-{
-	if (MAX_DESCRIPTORS)
-		return MAX_DESCRIPTORS;
-
-	int max = ulimit(4, 0);
-	if (max > 0)
-	{
-		MAX_DESCRIPTORS = max;
-		return max;
-	}
-	else
-	{
-		ServerInstance->Logs->Log("SOCKET", DEFAULT, "ERROR: Can't determine maximum number of open sockets!");
-		printf("ERROR: Can't determine maximum number of open sockets!\n");
-		ServerInstance->Exit(EXIT_STATUS_SOCKETENGINE);
-	}
-	return 0;
-}
-
-int EPollEngine::GetRemainingFds()
-{
-	return GetMaxFds() - CurrentSetSize;
-}
-
 int EPollEngine::DispatchEvents()
 {
 	socklen_t codesize = sizeof(int);
@@ -158,11 +164,13 @@ int EPollEngine::DispatchEvents()
 
 	for (int j = 0; j < i; j++)
 	{
+		EventHandler* eh = ref[events[j].data.fd];
+		if (!eh)
+			continue;
 		if (events[j].events & EPOLLHUP)
 		{
 			ErrorEvents++;
-			if (ref[events[j].data.fd])
-				ref[events[j].data.fd]->HandleEvent(EVENT_ERROR, 0);
+			eh->HandleEvent(EVENT_ERROR, 0);
 			continue;
 		}
 		if (events[j].events & EPOLLERR)
@@ -171,26 +179,20 @@ int EPollEngine::DispatchEvents()
 			/* Get error number */
 			if (getsockopt(events[j].data.fd, SOL_SOCKET, SO_ERROR, &errcode, &codesize) < 0)
 				errcode = errno;
-			if (ref[events[j].data.fd])
-				ref[events[j].data.fd]->HandleEvent(EVENT_ERROR, errcode);
+			eh->HandleEvent(EVENT_ERROR, errcode);
 			continue;
 		}
-		if (events[j].events & EPOLLOUT)
+		if (events[j].events & EPOLLIN)
 		{
-			WriteEvents++;
-			struct epoll_event ev;
-			memset(&ev,0,sizeof(ev));
-			ev.events = EPOLLIN;
-			ev.data.fd = events[j].data.fd;
-			epoll_ctl(EngineHandle, EPOLL_CTL_MOD, events[j].data.fd, &ev);
-			if (ref[events[j].data.fd])
-				ref[events[j].data.fd]->HandleEvent(EVENT_WRITE);
+			ReadEvents++;
+			SetEventMask(eh, eh->GetEventMask() & ~FD_READ_WILL_BLOCK);
+			eh->HandleEvent(EVENT_READ);
 		}
-		else
+		if (events[j].events & EPOLLOUT)
 		{
-			ReadEvents++;
-			if (ref[events[j].data.fd])
-				ref[events[j].data.fd]->HandleEvent(EVENT_READ);
+			WriteEvents++;
+			SetEventMask(eh, eh->GetEventMask() & ~FD_WRITE_WILL_BLOCK);
+			eh->HandleEvent(EVENT_WRITE);
 		}
 	}