after-delete-terminal-functions (was: 23.0.60; Emacs should survive a lost X connection)

[Stefan Monnier <monnier@iro.umontreal.ca>]

> emacs -Q -nw -f server-start

> emacsclient -c -d $DISPLAY&

> xkill 
> the emacsclient X11 frame

> then C-x C-c in the emacs -nw frame will warn about clients still being
> connected.

> Same thing when instead of using xkill, kill X11.

So I looked at the issue of letting know server.el when an X11
connection is abruptly closed as above.

I created a new event DELETE_TERMINAL_EVENT;
changed Fdelete_terminal to generate such an event;
changed x_connection_closed to call Fdelete_terminal

and ... it didn't work.  The problem is that x_connection_closed ends up
signalling an error, which flushes the input queue and hence throws away
the DELETE_TERMINAL_EVENT we just created.

So, I removed the `error' call, but this makes things worse, apparently:
Emacs then exits abruptly.  It seems that it's important to abort
execution at the end of x_connection_closed.  So I re[placed the `error'
call by a call to Fthrow.  This finally worked.

But now I wonder: is DELETE_TERMINAL_EVENT the right thing to do, or
should we use run-at-time instead?

Find attach my current attempt,


        Stefan


? src/.depend
cvs diff: Diffing src
Index: src/keyboard.c
===================================================================
RCS file: /sources/emacs/emacs/src/keyboard.c,v
retrieving revision 1.946
diff -u -r1.946 keyboard.c
--- src/keyboard.c	12 Feb 2008 04:05:29 -0000	1.946
+++ src/keyboard.c	13 Feb 2008 03:06:48 -0000
@@ -466,6 +466,7 @@
 Lisp_Object Qscroll_bar_movement;
 Lisp_Object Qswitch_frame;
 Lisp_Object Qdelete_frame;
+Lisp_Object Qdelete_terminal;
 Lisp_Object Qiconify_frame;
 Lisp_Object Qmake_frame_visible;
 Lisp_Object Qselect_window;
@@ -4195,6 +4196,11 @@
 	  kbd_fetch_ptr = event + 1;
 	}
 #endif
+      else if (event->kind == DELETE_TERMINAL_EVENT)
+	{
+	  obj = Fcons (Qdelete_terminal, Fcons (event->frame_or_window, Qnil));
+	  kbd_fetch_ptr = event + 1;
+	}
 #if defined (HAVE_X11) || defined (HAVE_NTGUI) || defined (MAC_OS)
       else if (event->kind == ICONIFY_EVENT)
 	{
@@ -11718,6 +11724,7 @@
   {&Qscroll_bar_movement, "scroll-bar-movement", &Qmouse_movement},
   {&Qswitch_frame,        "switch-frame",        &Qswitch_frame},
   {&Qdelete_frame,        "delete-frame",        &Qdelete_frame},
+  {&Qdelete_terminal,     "delete-terminal",     &Qdelete_terminal},
   {&Qiconify_frame,       "iconify-frame",       &Qiconify_frame},
   {&Qmake_frame_visible,  "make-frame-visible",  &Qmake_frame_visible},
   /* `select-window' should be handled just like `switch-frame'
Index: src/lisp.h
===================================================================
RCS file: /sources/emacs/emacs/src/lisp.h,v
retrieving revision 1.611
diff -u -r1.611 lisp.h
--- src/lisp.h	12 Feb 2008 21:35:14 -0000	1.611
+++ src/lisp.h	13 Feb 2008 03:06:49 -0000
@@ -3261,6 +3261,7 @@
 extern void fatal P_ ((const char *msgid, ...)) NO_RETURN;
 
 /* Defined in terminal.c */
+EXFUN (Fdelete_terminal, 2);
 extern void syms_of_terminal P_ ((void));
 
 #ifdef HAVE_WINDOW_SYSTEM
Index: src/puresize.h
===================================================================
RCS file: /sources/emacs/emacs/src/puresize.h,v
retrieving revision 1.104
diff -u -r1.104 puresize.h
--- src/puresize.h	1 Feb 2008 23:29:14 -0000	1.104
+++ src/puresize.h	13 Feb 2008 03:06:49 -0000
@@ -35,7 +35,7 @@
    amount of storage.  This is a lot more update-robust that defining
    BASE_PURESIZE or even PURESIZE directly.  */
 #ifndef SYSTEM_PURESIZE_EXTRA
-#define SYSTEM_PURESIZE_EXTRA 0
+#define SYSTEM_PURESIZE_EXTRA 1000000
 #endif
 
 #ifndef SITELOAD_PURESIZE_EXTRA
Index: src/termhooks.h
===================================================================
RCS file: /sources/emacs/emacs/src/termhooks.h,v
retrieving revision 1.91
diff -u -r1.91 termhooks.h
--- src/termhooks.h	8 Jan 2008 20:44:20 -0000	1.91
+++ src/termhooks.h	13 Feb 2008 03:06:49 -0000
@@ -137,6 +137,7 @@
   SELECTION_CLEAR_EVENT,	/* Another X client cleared our selection.  */
   BUFFER_SWITCH_EVENT,		/* A process filter has switched buffers.  */
   DELETE_WINDOW_EVENT,		/* An X client said "delete this window".  */
+  DELETE_TERMINAL_EVENT,        /* A terminal was deleted.  */
   MENU_BAR_EVENT,		/* An event generated by the menu bar.
 				   The frame_or_window field's cdr holds the
 				   Lisp-level event value.
Index: src/terminal.c
===================================================================
RCS file: /sources/emacs/emacs/src/terminal.c,v
retrieving revision 1.9
diff -u -r1.9 terminal.c
--- src/terminal.c	11 Feb 2008 03:51:39 -0000	1.9
+++ src/terminal.c	13 Feb 2008 03:06:49 -0000
@@ -320,6 +320,15 @@
 	error ("Attempt to delete the sole active display terminal");
     }
 
+  if (!NILP (Vrun_hooks))
+    {
+      struct input_event ie;
+      ie.kind = DELETE_TERMINAL_EVENT;
+      ie.arg = Qnil;
+      XSETTERMINAL (ie.frame_or_window, t);
+      kbd_buffer_store_event (&ie);
+    }
+
   if (t->delete_terminal_hook)
     (*t->delete_terminal_hook) (t);
   else
Index: src/xterm.c
===================================================================
RCS file: /sources/emacs/emacs/src/xterm.c,v
retrieving revision 1.975
diff -u -r1.975 xterm.c
--- src/xterm.c	10 Feb 2008 21:56:37 -0000	1.975
+++ src/xterm.c	13 Feb 2008 03:06:50 -0000
@@ -8093,10 +8093,11 @@
      OpenWindows in certain situations.  I suspect that is a bug
      in OpenWindows.  I don't know how to circumvent it here.  */
 
+  if (dpyinfo)
+    {
 #ifdef USE_X_TOOLKIT
   /* If DPYINFO is null, this means we didn't open the display
      in the first place, so don't try to close it.  */
-  if (dpyinfo)
     {
       extern void (*fatal_error_signal_hook) P_ ((void));
       fatal_error_signal_hook = x_fatal_error_signal;
@@ -8106,12 +8107,9 @@
 #endif
 
 #ifdef USE_GTK
-  if (dpyinfo)
     xg_display_close (dpyinfo->display);
 #endif
 
-  if (dpyinfo)
-    {
       /* Indicate that this display is dead.  */
       dpyinfo->display = 0;
 
@@ -8121,7 +8119,14 @@
         /* We have just closed all frames on this display. */
         abort ();
 
-      x_delete_display (dpyinfo);
+      {
+	struct terminal *t = terminal_list;
+	Lisp_Object tmp;
+	while (t && t->display_info.x != dpyinfo)
+	  t = t->next_terminal;
+	XSETTERMINAL (tmp, t);
+	Fdelete_terminal (tmp, Qnoelisp);
+      }
     }
 
   x_uncatch_errors ();
@@ -8146,7 +8151,10 @@
      error might not be the best thing to do.  I'd vote for creating an
      elisp event and stuffing it in the queue so people can bind to it via
      the global map.  --Stef  */
-  error ("%s", error_msg);
+  /* We used to throw an error, but this flushes the input_event queue,
+     on which we just put a DELETE_TERMINAL_EVENT :-(
+     error ("%s", error_msg) */
+  Fthrow (Qtop_level, Qnil);
 }
 
 /* We specifically use it before defining it, so that gcc doesn't inline it,
@@ -11812,6 +11812,10 @@
     return;
 
   BLOCK_INPUT;
+  /* When called from x_connection_closed, the display is already closed
+     and dpyinfo->display was set to 0 to indicate that.  */
+  if (dpyinfo->display)
+    {
 #ifdef USE_FONT_BACKEND
   if (! enable_font_backend)
 #endif
@@ -11834,6 +11838,7 @@
   XCloseDisplay (dpyinfo->display);
 #endif
 #endif /* ! USE_GTK */
+    }
 
   x_delete_display (dpyinfo);
   UNBLOCK_INPUT;
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