(reset_var_on_error): New fun.

(signal_before_change, signal_after_change):
Use it to reset (after|before)-change-functions to nil in case of error.
Bind inhibit-modification-hooks to t.
Don't bind (after|before)-change-functions to nil while they run.

2 files changed, 46 insertions, 62 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index add0663a648..bf015d6959f 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,11 @@
+2007-08-21  Stefan Monnier  <monnier@iro.umontreal.ca>
+
+        * insdel.c (reset_var_on_error): New fun.
+        (signal_before_change, signal_after_change):
+        Use it to reset (after|before)-change-functions to nil in case of error.
+        Bind inhibit-modification-hooks to t.
+        Don't bind (after|before)-change-functions to nil while they run.
+
 2007-08-19  Andreas Schwab  <schwab@suse.de>
 
         * alloc.c (pure): Round PURESIZE up.
diff --git a/src/insdel.c b/src/insdel.c
index 14e7478e69a..cd8e2738f9a 100644
--- a/src/insdel.c
+++ b/src/insdel.c
@@ -2137,6 +2137,21 @@ prepare_to_modify_buffer (start, end, preserve_ptr)
 #define FETCH_END                               \
   (! NILP (end_marker) ? Fmarker_position (end_marker) : end)
 
+/* Set a variable to nil if an error occurred.
+   Don't change the variable if there was no error.
+   VAL is a cons-cell (VARIABLE . NO-ERROR-FLAG).
+   VARIABLE is the variable to maybe set to nil.
+   NO-ERROR-FLAG is nil if there was an error,
+   anything else meaning no error (so this function does nothing).  */
+Lisp_Object
+reset_var_on_error (val)
+     Lisp_Object val;
+{
+  if (NILP (XCDR (val)))
+    Fset (XCAR (val), Qnil);
+  return Qnil;
+}
+
 /* Signal a change to the buffer immediately before it happens.
    START_INT and END_INT are the bounds of the text to be changed.
 
@@ -2152,6 +2167,7 @@ signal_before_change (start_int, end_int, preserve_ptr)
   Lisp_Object start_marker, end_marker;
   Lisp_Object preserve_marker;
   struct gcpro gcpro1, gcpro2, gcpro3;
+  int count = SPECPDL_INDEX ();
 
   if (inhibit_modification_hooks)
     return;
@@ -2163,6 +2179,8 @@ signal_before_change (start_int, end_int, preserve_ptr)
   end_marker = Qnil;
   GCPRO3 (preserve_marker, start_marker, end_marker);
 
+  specbind (Qinhibit_modification_hooks, Qt);
+
   /* If buffer is unmodified, run a special hook for that case.  */
   if (SAVE_MODIFF >= MODIFF
       && !NILP (Vfirst_change_hook)
@@ -2177,46 +2195,22 @@ signal_before_change (start_int, end_int, preserve_ptr)
   if (!NILP (Vbefore_change_functions))
     {
       Lisp_Object args[3];
-      Lisp_Object before_change_functions;
-      Lisp_Object after_change_functions;
-      struct gcpro gcpro1, gcpro2;
-      struct buffer *old = current_buffer;
-      struct buffer *new;
+      Lisp_Object rvoe_arg = Fcons (Qbefore_change_functions, Qnil);
 
       PRESERVE_VALUE;
       PRESERVE_START_END;
 
-      /* "Bind" before-change-functions and after-change-functions
-         to nil--but in a way that errors don't know about.
-         That way, if there's an error in them, they will stay nil.  */
-      before_change_functions = Vbefore_change_functions;
-      after_change_functions = Vafter_change_functions;
-      Vbefore_change_functions = Qnil;
-      Vafter_change_functions = Qnil;
-      GCPRO2 (before_change_functions, after_change_functions);
+      /* Mark before-change-functions to be reset to nil in case of error.  */
+      record_unwind_protect (reset_var_on_error, rvoe_arg);
 
       /* Actually run the hook functions.  */
       args[0] = Qbefore_change_functions;
       args[1] = FETCH_START;
       args[2] = FETCH_END;
-      run_hook_list_with_args (before_change_functions, 3, args);
+      Frun_hook_with_args (3, args);
 
-      /* "Unbind" the variables we "bound" to nil.  Beware a
-         buffer-local hook which changes the buffer when run (e.g. W3).  */
-      if (old != current_buffer)
-        {
-          new = current_buffer;
-          set_buffer_internal (old);
-          Vbefore_change_functions = before_change_functions;
-          Vafter_change_functions = after_change_functions;
-          set_buffer_internal (new);
-        }
-      else
-        {
-          Vbefore_change_functions = before_change_functions;
-          Vafter_change_functions = after_change_functions;
-        }
-      UNGCPRO;
+      /* There was no error: unarm the reset_on_error.  */
+      XSETCDR (rvoe_arg, Qt);
     }
 
   if (current_buffer->overlays_before || current_buffer->overlays_after)
@@ -2232,6 +2226,8 @@ signal_before_change (start_int, end_int, preserve_ptr)
     free_marker (end_marker);
   RESTORE_VALUE;
   UNGCPRO;
+
+  unbind_to (count, Qnil);
 }
 
 /* Signal a change immediately after it happens.
@@ -2245,6 +2241,7 @@ void
 signal_after_change (charpos, lendel, lenins)
      int charpos, lendel, lenins;
 {
+  int count = SPECPDL_INDEX ();
   if (inhibit_modification_hooks)
     return;
 
@@ -2275,48 +2272,25 @@ signal_after_change (charpos, lendel, lenins)
   if (!NILP (combine_after_change_list))
     Fcombine_after_change_execute ();
 
+  specbind (Qinhibit_modification_hooks, Qt);
+
   if (!NILP (Vafter_change_functions))
     {
       Lisp_Object args[4];
-      Lisp_Object before_change_functions;
-      Lisp_Object after_change_functions;
-      struct buffer *old = current_buffer;
-      struct buffer *new;
-      struct gcpro gcpro1, gcpro2;
-
-      /* "Bind" before-change-functions and after-change-functions
-         to nil--but in a way that errors don't know about.
-         That way, if there's an error in them, they will stay nil.  */
-      before_change_functions = Vbefore_change_functions;
-      after_change_functions = Vafter_change_functions;
-      Vbefore_change_functions = Qnil;
-      Vafter_change_functions = Qnil;
-      GCPRO2 (before_change_functions, after_change_functions);
+      Lisp_Object rvoe_arg = Fcons (Qafter_change_functions, Qnil);
+
+      /* Mark after-change-functions to be reset to nil in case of error.  */
+      record_unwind_protect (reset_var_on_error, rvoe_arg);
 
       /* Actually run the hook functions.  */
       args[0] = Qafter_change_functions;
       XSETFASTINT (args[1], charpos);
       XSETFASTINT (args[2], charpos + lenins);
       XSETFASTINT (args[3], lendel);
-      run_hook_list_with_args (after_change_functions,
-                               4, args);
+      Frun_hook_with_args (4, args);
 
-      /* "Unbind" the variables we "bound" to nil.  Beware a
-         buffer-local hook which changes the buffer when run (e.g. W3).  */
-      if (old != current_buffer)
-        {
-          new = current_buffer;
-          set_buffer_internal (old);
-          Vbefore_change_functions = before_change_functions;
-          Vafter_change_functions = after_change_functions;
-          set_buffer_internal (new);
-        }
-      else
-        {
-          Vbefore_change_functions = before_change_functions;
-          Vafter_change_functions = after_change_functions;
-        }
-      UNGCPRO;
+      /* There was no error: unarm the reset_on_error.  */
+      XSETCDR (rvoe_arg, Qt);
     }
 
   if (current_buffer->overlays_before || current_buffer->overlays_after)
@@ -2332,6 +2306,8 @@ signal_after_change (charpos, lendel, lenins)
   if (lendel == 0)
     report_interval_modification (make_number (charpos),
                                   make_number (charpos + lenins));
+
+  unbind_to (count, Qnil);
 }
 
 Lisp_Object