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, 12 insertions, 4 deletions

diff --git a/src/w32term.h b/src/w32term.h
index d809be3c03d..8585c8190db 100644
--- a/src/w32term.h
+++ b/src/w32term.h
@@ -727,10 +727,18 @@ extern void x_delete_display (struct w32_display_info *dpyinfo);
 
 extern void x_query_color (struct frame *, XColor *);
 
-extern volatile int notification_buffer_in_use;
-extern BYTE file_notifications[16384];
-extern DWORD notifications_size;
-extern void *notifications_desc;
+#define FILE_NOTIFICATIONS_SIZE 16384
+/* Notifications come in sets.  We use a doubly linked list with a
+   sentinel to communicate those sets from the watching threads to the
+   main thread.  */
+struct notifications_set {
+  LPBYTE notifications;
+  DWORD size;
+  void *desc;
+  struct notifications_set *next;
+  struct notifications_set *prev;
+};
+extern struct notifications_set *notifications_set_head;
 extern Lisp_Object w32_get_watch_object (void *);
 extern Lisp_Object lispy_file_action (DWORD);
 extern int handle_file_notifications (struct input_event *);