Fixed select()ing 0 sockets on Windows

src/socketengines/socketengine_select.cpp

@@ -1,12 +1,14 @@
 #include "module.h"
 
 static int MaxFD;
+static unsigned FDCount;
 static fd_set ReadFDs;
 static fd_set WriteFDs;
 
 void SocketEngine::Init()
 {
 	MaxFD = 0;
+	FDCount = 0;
 	FD_ZERO(&ReadFDs);
 	FD_ZERO(&WriteFDs);
 }
@@ -22,10 +24,6 @@ void SocketEngine::Shutdown()
 		delete s;
 	}
 	Sockets.clear();
-
-	MaxFD = 0;
-	FD_ZERO(&ReadFDs);
-	FD_ZERO(&WriteFDs);
 }
 
 void SocketEngine::AddSocket(Socket *s)
@@ -34,6 +32,7 @@ void SocketEngine::AddSocket(Socket *s)
 		MaxFD = s->GetFD();
 	FD_SET(s->GetFD(), &ReadFDs);
 	Sockets.insert(std::make_pair(s->GetFD(), s));
+	++FDCount;
 }
 
 void SocketEngine::DelSocket(Socket *s)
@@ -43,6 +42,7 @@ void SocketEngine::DelSocket(Socket *s)
 	FD_CLR(s->GetFD(), &ReadFDs);
 	FD_CLR(s->GetFD(), &WriteFDs);
 	Sockets.erase(s->GetFD());
+	--FDCount;
 }
 
 void SocketEngine::MarkWritable(Socket *s)
@@ -68,6 +68,20 @@ void SocketEngine::Process()
 	tval.tv_sec = Config->ReadTimeout;
 	tval.tv_usec = 0;
 
+#ifdef _WIN32
+	/* We can use the socket engine to "sleep" services for a period of
+	 * time between connections to the uplink, which allows modules,
+	 * timers, etc to function properly. Windows, being as useful as it is,
+	 * does not allow to select() on 0 sockets and will immediately return error.
+	 * Thus:
+	 */
+	if (FDCount == 0)
+	{
+		sleep(Config->ReadTimeout);
+		return;
+	}
+#endif
+
 	int sresult = select(MaxFD + 1, &rfdset, &wfdset, &efdset, &tval);
 	Anope::CurTime = time(NULL);