Improve w32notify notifications

* src/w32notify.c (DIRWATCH_BUFFER_SIZE): New macro.
(struct notification): 'terminate' is now a HANDLE.
(send_notifications): Argument is now a pointer to a
notification.  Don't loop waiting for the notification to be
acknowledged by the main thread; instead, just add the
notification to the linked list of notifications waiting to be
acknowledged.
(watch_end): Don't close the directory handle.
(watch_completion): Allocate a new notification structure to be
added to the notifications set.  Call ReadDirectoryChangesW
immediately after adding the new notification, and before sending
a message to the main thread about them.
(watch_worker): Don't loop calling ReadDirectoryChangesW; instead,
call it just once -- it will be called again in watch_completion.
Loop waiting for the main thread's indication to terminate.
(start_watching): Create the event to be used to indicate to the
worker thread that its should terminate.
(remove_watch): Indicate to the worker thread that it should
terminate.
* src/w32term.c (queue_notifications): Loop over all the
notifications in the linked list, processing all of them in one
go.
* src/w32inevt.c (handle_file_notifications): Loop over all the
notifications in the linked list.
* src/w32xfns.c (init_crit): Initialize the linked list of file
notifications.
(delete_crit): Free the linked list of file notifications,
including any unprocessed notifications left in it.
* src/w32term.h (struct notifications_se): New struct.

* test/lisp/filenotify-tests.el (file-notify-test02-events)
(file-notify-test05-dir-validity): Add read-event calls to
facilitate event recognition by the main thread in batch mode.

1 files changed, 67 insertions, 48 deletions

diff --git a/src/w32inevt.c b/src/w32inevt.c
index a33f82dc7db..2269d318051 100644
--- a/src/w32inevt.c
+++ b/src/w32inevt.c
@@ -620,70 +620,89 @@ maybe_generate_resize_event (void)
 int
 handle_file_notifications (struct input_event *hold_quit)
 {
-  BYTE *p = file_notifications;
-  FILE_NOTIFY_INFORMATION *fni = (PFILE_NOTIFY_INFORMATION)p;
-  const DWORD min_size
-    = offsetof (FILE_NOTIFY_INFORMATION, FileName) + sizeof(wchar_t);
-  struct input_event inev;
+  struct notifications_set *ns = NULL;
   int nevents = 0;
+  int done = 0;
 
   /* We cannot process notification before Emacs is fully initialized,
      since we need the UTF-16LE coding-system to be set up.  */
   if (!initialized)
     {
-      notification_buffer_in_use = 0;
       return nevents;
     }
 
-  enter_crit ();
-  if (notification_buffer_in_use)
+  while (!done)
     {
-      DWORD info_size = notifications_size;
-      Lisp_Object cs = Qutf_16le;
-      Lisp_Object obj = w32_get_watch_object (notifications_desc);
-
-      /* notifications_size could be zero when the buffer of
-	 notifications overflowed on the OS level, or when the
-	 directory being watched was itself deleted.  Do nothing in
-	 that case.  */
-      if (info_size
-	  && !NILP (obj) && CONSP (obj))
-	{
-	  Lisp_Object callback = XCDR (obj);
+      ns = NULL;
 
-	  EVENT_INIT (inev);
+      /* Find out if there is a record available in the linked list of
+	 notifications sets.  If so, unlink te set from the linked list.
+	 Use the critical section.  */
+      enter_crit ();
+      if (notifications_set_head->next != notifications_set_head)
+	{
+	  ns = notifications_set_head->next;
+	  ns->prev->next = ns->next;
+	  ns->next->prev = ns->prev;
+	}
+      else
+	done = 1;
+      leave_crit();
 
-	  while (info_size >= min_size)
+      if (ns)
+	{
+	  BYTE *p = ns->notifications;
+	  FILE_NOTIFY_INFORMATION *fni = (PFILE_NOTIFY_INFORMATION)p;
+	  const DWORD min_size
+	    = offsetof (FILE_NOTIFY_INFORMATION, FileName) + sizeof(wchar_t);
+	  struct input_event inev;
+	  DWORD info_size = ns->size;
+	  Lisp_Object cs = Qutf_16le;
+	  Lisp_Object obj = w32_get_watch_object (ns->desc);
+
+	  /* notifications size could be zero when the buffer of
+	     notifications overflowed on the OS level, or when the
+	     directory being watched was itself deleted.  Do nothing in
+	     that case.  */
+	  if (info_size
+	      && !NILP (obj) && CONSP (obj))
 	    {
-	      Lisp_Object utf_16_fn
-		= make_unibyte_string ((char *)fni->FileName,
-				       fni->FileNameLength);
-	      /* Note: mule-conf is preloaded, so utf-16le must
-		 already be defined at this point.  */
-	      Lisp_Object fname
-		= code_convert_string_norecord (utf_16_fn, cs, 0);
-	      Lisp_Object action = lispy_file_action (fni->Action);
-
-	      inev.kind = FILE_NOTIFY_EVENT;
-	      inev.timestamp = GetTickCount ();
-	      inev.modifiers = 0;
-	      inev.frame_or_window = callback;
-	      inev.arg = Fcons (action, fname);
-	      inev.arg = list3 (make_pointer_integer (notifications_desc),
-				action, fname);
-	      kbd_buffer_store_event_hold (&inev, hold_quit);
-	      nevents++;
-
-	      if (!fni->NextEntryOffset)
-		break;
-	      p += fni->NextEntryOffset;
-	      fni = (PFILE_NOTIFY_INFORMATION)p;
-	      info_size -= fni->NextEntryOffset;
+	      Lisp_Object callback = XCDR (obj);
+
+	      EVENT_INIT (inev);
+
+	      while (info_size >= min_size)
+		{
+		  Lisp_Object utf_16_fn
+		    = make_unibyte_string ((char *)fni->FileName,
+					   fni->FileNameLength);
+		  /* Note: mule-conf is preloaded, so utf-16le must
+		     already be defined at this point.  */
+		  Lisp_Object fname
+		    = code_convert_string_norecord (utf_16_fn, cs, 0);
+		  Lisp_Object action = lispy_file_action (fni->Action);
+
+		  inev.kind = FILE_NOTIFY_EVENT;
+		  inev.timestamp = GetTickCount ();
+		  inev.modifiers = 0;
+		  inev.frame_or_window = callback;
+		  inev.arg = Fcons (action, fname);
+		  inev.arg = list3 (make_pointer_integer (ns->desc),
+				    action, fname);
+		  kbd_buffer_store_event_hold (&inev, hold_quit);
+		  nevents++;
+		  if (!fni->NextEntryOffset)
+		    break;
+		  p += fni->NextEntryOffset;
+		  fni = (PFILE_NOTIFY_INFORMATION)p;
+		  info_size -= fni->NextEntryOffset;
+		}
 	    }
+	  /* Free this notification set.  */
+	  free (ns->notifications);
+	  free (ns);
 	}
-      notification_buffer_in_use = 0;
     }
-  leave_crit ();
   return nevents;
 }
 #else  /* !HAVE_W32NOTIFY */