os: Implement support for NotifyFd X_NOTIFY_WRITE and removal of AddEnabledDevices/RemoveEnabledDevices

 Backported from X.org:

 commit be5a513fee6cbf29ef7570e57eb0436d70fbd88c
 Author: Keith Packard <keithp@keithp.com>
 Date:   Mon Dec 7 15:12:14 2015 -0800

    Remove AddEnabledDevice and AddGeneralSocket APIs

    All uses of these interfaces should instead be using the NotifyFd API
    instead.

    Signed-off-by: Keith Packard <keithp@keithp.com>
    Reviewed-by: Adam Jackson <ajax@redhat.com>

 commit 4020aacd1fc5b9c63369f011aeb9120af9c55218
 Author: Keith Packard <keithp@keithp.com>
 Date:   Wed Nov 11 22:02:03 2015 -0800

    os: Implement support for NotifyFd X_NOTIFY_WRITE

    This adds the ability to be notified when a file descriptor is
    available for writing.

    Reviewed-by: Adam Jackson <ajax@redhat.com>
    Signed-off-by: Keith Packard <keithp@keithp.com>

 Backported-to-NX-by: Mike Gabriel <mike.gabriel@das-netzwerkteam.de>

1 files changed, 39 insertions, 33 deletions

diff --git a/nx-X11/programs/Xserver/os/connection.c b/nx-X11/programs/Xserver/os/connection.c
index 23df49883..966fe208d 100644
--- a/nx-X11/programs/Xserver/os/connection.c
+++ b/nx-X11/programs/Xserver/os/connection.c
@@ -48,8 +48,8 @@ SOFTWARE.
  *  Stuff to create connections --- OS dependent
  *
  *      EstablishNewConnections, CreateWellKnownSockets, ResetWellKnownSockets,
- *      CloseDownConnection, CheckConnections, AddEnabledDevice,
- *	RemoveEnabledDevice, OnlyListToOneClient,
+ *      CloseDownConnection, CheckConnections,
+ *      OnlyListToOneClient,
  *      ListenToAllClients,
  *
  *      (WaitForSomething is in its own file)
@@ -123,18 +123,19 @@ SOFTWARE.
 int lastfdesc;			/* maximum file descriptor */
 
 fd_set WellKnownConnections;	/* Listener mask */
-fd_set EnabledDevices;		/* mask for input devices that are on */
 fd_set NotifyReadFds;           /* mask for other file descriptors */
+fd_set NotifyWriteFds;          /* mask for other write file descriptors */
 fd_set AllSockets;		/* select on this */
 fd_set AllClients;		/* available clients */
 fd_set LastSelectMask;		/* mask returned from last select call */
+fd_set LastSelectWriteMask;     /* mask returned from last select call */
 fd_set ClientsWithInput;	/* clients with FULL requests in buffer */
 fd_set ClientsWriteBlocked;	/* clients who cannot receive output */
 fd_set OutputPending;		/* clients with reply/event data ready to go */
 int MaxClients = 0;
+int NumNotifyWriteFd;           /* Number of NotifyFd members with write set */
 Bool NewOutputPending;		/* not yet attempted to write some new output */
-Bool AnyClientsWriteBlocked;	/* true if some client blocked on write */
-
+Bool AnyWritesPending;          /* true if some client blocked on write or NotifyFd with write */
 Bool RunFromSmartParent;	/* send SIGUSR1 to parent process */
 Bool PartialNetwork;		/* continue even if unable to bind all addrs */
 static Pid_t ParentProcess;
@@ -913,8 +914,8 @@ CloseDownFileDescriptor(OsCommPtr oc)
 	FD_CLR(connection, &SavedClientsWithInput);
     }
     FD_CLR(connection, &ClientsWriteBlocked);
-    if (!XFD_ANYSET(&ClientsWriteBlocked))
-    	AnyClientsWriteBlocked = FALSE;
+    if (!XFD_ANYSET(&ClientsWriteBlocked) && NumNotifyWriteFd == 0)
+	AnyWritesPending = FALSE;
     FD_CLR(connection, &OutputPending);
 }
 
@@ -997,24 +998,6 @@ CloseDownConnection(ClientPtr client)
 	AuditF("client %d disconnected\n", client->index);
 }
 
-void
-AddEnabledDevice(int fd)
-{
-    FD_SET(fd, &EnabledDevices);
-    FD_SET(fd, &AllSockets);
-    if (GrabInProgress)
-	FD_SET(fd, &SavedAllSockets);
-}
-
-void
-RemoveEnabledDevice(int fd)
-{
-    FD_CLR(fd, &EnabledDevices);
-    FD_CLR(fd, &AllSockets);
-    if (GrabInProgress)
-	FD_CLR(fd, &SavedAllSockets);
-}
-
 struct notify_fd {
     struct xorg_list list;
     int fd;
@@ -1036,6 +1019,7 @@ InitNotifyFds(void)
 	     RemoveNotifyFd(s->fd);
 
     xorg_list_init(&notify_fds);
+    NumNotifyWriteFd = 0;
     been_here = 1;
 }
 
@@ -1071,12 +1055,30 @@ SetNotifyFd(int fd, NotifyFdProcPtr notify, int mask, void *data)
     if (changes & X_NOTIFY_READ) {
 	if (mask & X_NOTIFY_READ) {
 	    FD_SET(fd, &NotifyReadFds);
-	    AddGeneralSocket(fd);
+	    FD_SET(fd, &AllSockets);
+	    if (GrabInProgress)
+		FD_SET(fd, &SavedAllSockets);
 	} else {
-	    RemoveGeneralSocket(fd);
+	    FD_CLR(fd, &AllSockets);
+	    if (GrabInProgress)
+		FD_CLR(fd, &SavedAllSockets);
 	     FD_CLR(fd, &NotifyReadFds);
 	}
     }
+
+    if (changes & X_NOTIFY_WRITE) {
+	if (mask & X_NOTIFY_WRITE) {
+	    FD_SET(fd, &NotifyWriteFds);
+	    if (!NumNotifyWriteFd++)
+		AnyWritesPending = TRUE;
+	} else {
+	    FD_CLR(fd, &NotifyWriteFds);
+	    if (!--NumNotifyWriteFd)
+		if (!XFD_ANYSET(&ClientsWriteBlocked))
+		    AnyWritesPending = FALSE;
+	}
+    }
+
     if (mask == 0) {
 	xorg_list_del(&n->list);
 	free(n);
@@ -1098,12 +1100,16 @@ SetNotifyFd(int fd, NotifyFdProcPtr notify, int mask, void *data)
 void
 HandleNotifyFds(void)
 {
-    struct notify_fd *s, *next;
-
-    xorg_list_for_each_entry_safe(s, next, &notify_fds, list) {
-	if (FD_ISSET(s->fd, &LastSelectMask)) {
-	    s->notify(s->fd, X_NOTIFY_READ, s->data);
-	}
+    struct notify_fd *n, *next;
+
+    xorg_list_for_each_entry_safe(n, next, &notify_fds, list) {
+	int ready = 0;
+	if ((n->mask & X_NOTIFY_READ) && FD_ISSET(n->fd, &LastSelectMask))
+	    ready |= X_NOTIFY_READ;
+	if ((n->mask & X_NOTIFY_WRITE) & FD_ISSET(n->fd, &LastSelectWriteMask))
+	    ready |= X_NOTIFY_WRITE;
+	if (ready != 0)
+	    n->notify(n->fd, ready, n->data);
     }
 }