Revert last save_excursion_save and save_excursion_restore changes.

* alloc.c, editfns.c, marker.c, lisp.h: Revert.
Lots of crashes reported by Chong Yidong <cyd@gnu.org>.

5 files changed, 123 insertions, 180 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index adcdfb7c056..93697303cbb 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,9 +1,15 @@
 2012-07-27  Dmitry Antipov  <dmantipov@yandex.ru>
 
+        Revert last save_excursion_save and save_excursion_restore changes.
+        * alloc.c, editfns.c, marker.c, lisp.h: Revert.
+        Lots of crashes reported by Chong Yidong <cyd@gnu.org>.
+
+2012-07-27  Dmitry Antipov  <dmantipov@yandex.ru>
+
         Fix recently-introduced typos in Windows port.
         Reported by Martin Rudalics <rudalics@gmx.at>.
         * w32.c (init_environment): Replace comma with semicolon.
-        * w32fns.c (syms_of_w32fns): Likewise.
+        * w32fns.c (syms_of_w32fns): Add missing parenthesis.
 
 2012-07-27  Paul Eggert  <eggert@cs.ucla.edu>
 
diff --git a/src/alloc.c b/src/alloc.c
index 948ce7b6f5c..c7936921a09 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -3685,10 +3685,17 @@ DEFUN ("make-marker", Fmake_marker, Smake_marker, 0, 0, 0,
        doc: /* Return a newly allocated marker which does not point at any place.  */)
   (void)
 {
-  register Lisp_Object marker = allocate_misc (Lisp_Misc_Marker);
+  register Lisp_Object val;
+  register struct Lisp_Marker *p;
 
-  init_marker (XMARKER (marker), NULL, 0, 0, 0);
-  return marker;
+  val = allocate_misc (Lisp_Misc_Marker);
+  p = XMARKER (val);
+  p->buffer = 0;
+  p->bytepos = 0;
+  p->charpos = 0;
+  p->next = NULL;
+  p->insertion_type = 0;
+  return val;
 }
 
 /* Return a newly allocated marker which points into BUF
@@ -3697,23 +3704,24 @@ DEFUN ("make-marker", Fmake_marker, Smake_marker, 0, 0, 0,
 Lisp_Object
 build_marker (struct buffer *buf, ptrdiff_t charpos, ptrdiff_t bytepos)
 {
-  register Lisp_Object marker = allocate_misc (Lisp_Misc_Marker);
-
-  /* Use Fmake_marker to create marker points to nowhere.  */
-  eassert (buf != NULL);
+  Lisp_Object obj;
+  struct Lisp_Marker *m;
 
   /* No dead buffers here.  */
   eassert (!NILP (BVAR (buf, name)));
 
-  /* In a single-byte buffer, two positions must be equal.
-     Otherwise, every character is at least one byte.  */
-  if (BUF_Z (buf) == BUF_Z_BYTE (buf))
-    eassert (charpos == bytepos);
-  else
-    eassert (charpos <= bytepos);
-
-  init_marker (XMARKER (marker), buf, charpos, bytepos, 0);
-  return marker;
+  /* Every character is at least one byte.  */
+  eassert (charpos <= bytepos);
+
+  obj = allocate_misc (Lisp_Misc_Marker);
+  m = XMARKER (obj);
+  m->buffer = buf;
+  m->charpos = charpos;
+  m->bytepos = bytepos;
+  m->insertion_type = 0;
+  m->next = BUF_MARKERS (buf);
+  BUF_MARKERS (buf) = m;
+  return obj;
 }
 
 /* Put MARKER back on the free list after using it temporarily.  */
@@ -6081,19 +6089,6 @@ mark_object (Lisp_Object arg)
           case PVEC_SUBR:
             break;
 
-          case PVEC_EXCURSION:
-            {
-              struct Lisp_Excursion *e = (struct Lisp_Excursion *) ptr;
-              /* No Lisp_Objects but two special pointers to mark here.  */
-              eassert (e->buffer != NULL);
-              eassert (e->window != NULL);
-              if (!VECTOR_MARKED_P (e->buffer))
-                mark_buffer (e->buffer);
-              if (!VECTOR_MARKED_P (e->window))
-                mark_vectorlike ((struct Lisp_Vector *) e->window);
-            }
-            break;
-
           case PVEC_FREE:
             abort ();
 
diff --git a/src/editfns.c b/src/editfns.c
index 8b6c29bc934..f174594dd97 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -821,104 +821,104 @@ This function does not move point.  */)
                               Qnil, Qt, Qnil);
 }
 
-/* Record buffer state before entering Fsave_excursion. */
-
+
 Lisp_Object
 save_excursion_save (void)
 {
-  Lisp_Object excursion;
-  struct buffer *b = current_buffer;
-  struct window *w = XWINDOW (selected_window);
-  struct Lisp_Excursion *ex = xmalloc (sizeof *ex);
-  struct Lisp_Marker *m = XMARKER (BVAR (b, mark));
-
-  ex->size = 0;
-  ex->buffer = b;
-  ex->window = w;
-  ex->visible = (XBUFFER (w->buffer) == b);
-  ex->active = !NILP (BVAR (b, mark_active));
-
-  /* We do not initialize type and gcmarkbit since this marker
-     is never referenced via Lisp_Object and invisible for GC.  */
-  init_marker (&ex->point, b, PT, PT_BYTE, 0);
-
-  /* Likewise.  Note that charpos and bytepos may be zero.  */
-  init_marker (&ex->mark, m->buffer, m->charpos, 
-               m->bytepos, m->insertion_type);
-
-  /* Make it a pseudovector and return excursion object.  */
-  XSETTYPED_PVECTYPE (ex, size, PVEC_EXCURSION);
-  XSETEXCURSION (excursion, ex);
-  return excursion;
+  int visible = (XBUFFER (XWINDOW (selected_window)->buffer)
+                 == current_buffer);
+
+  return Fcons (Fpoint_marker (),
+                Fcons (Fcopy_marker (BVAR (current_buffer, mark), Qnil),
+                       Fcons (visible ? Qt : Qnil,
+                              Fcons (BVAR (current_buffer, mark_active),
+                                     selected_window))));
 }
 
-/* Restore buffer state before leaving Fsave_excursion.  */
-
 Lisp_Object
-save_excursion_restore (Lisp_Object obj)
+save_excursion_restore (Lisp_Object info)
 {
-  struct Lisp_Excursion *ex = XEXCURSION (obj);
-  struct buffer *b = ex->buffer;
-
-  eassert (b != NULL);
-  eassert (ex->window != NULL);
-
-  /* Restore buffer state only if the buffer is live.
-     Otherwise, just cancel an excursion state.  */
+  Lisp_Object tem, tem1, omark, nmark;
+  struct gcpro gcpro1, gcpro2, gcpro3;
+  int visible_p;
+
+  tem = Fmarker_buffer (XCAR (info));
+  /* If buffer being returned to is now deleted, avoid error */
+  /* Otherwise could get error here while unwinding to top level
+     and crash */
+  /* In that case, Fmarker_buffer returns nil now.  */
+  if (NILP (tem))
+    return Qnil;
 
-  if (!NILP (BVAR (b, name)))
+  omark = nmark = Qnil;
+  GCPRO3 (info, omark, nmark);
+
+  Fset_buffer (tem);
+
+  /* Point marker.  */
+  tem = XCAR (info);
+  Fgoto_char (tem);
+  unchain_marker (XMARKER (tem));
+
+  /* Mark marker.  */
+  info = XCDR (info);
+  tem = XCAR (info);
+  omark = Fmarker_position (BVAR (current_buffer, mark));
+  Fset_marker (BVAR (current_buffer, mark), tem, Fcurrent_buffer ());
+  nmark = Fmarker_position (tem);
+  unchain_marker (XMARKER (tem));
+
+  /* visible */
+  info = XCDR (info);
+  visible_p = !NILP (XCAR (info));
+
+#if 0 /* We used to make the current buffer visible in the selected window
+         if that was true previously.  That avoids some anomalies.
+         But it creates others, and it wasn't documented, and it is simpler
+         and cleaner never to alter the window/buffer connections.  */
+  tem1 = Fcar (tem);
+  if (!NILP (tem1)
+      && current_buffer != XBUFFER (XWINDOW (selected_window)->buffer))
+    Fswitch_to_buffer (Fcurrent_buffer (), Qnil);
+#endif /* 0 */
+
+  /* Mark active */
+  info = XCDR (info);
+  tem = XCAR (info);
+  tem1 = BVAR (current_buffer, mark_active);
+  BVAR (current_buffer, mark_active) = tem;
+
+  /* If mark is active now, and either was not active
+     or was at a different place, run the activate hook.  */
+  if (! NILP (tem))
     {
-      int active;
-      struct Lisp_Marker *m;
-      ptrdiff_t oldpos, newpos;
-
-      /* Restore current buffer.  */
-      set_buffer_internal (b);
-
-      /* Restore buffer position.  */
-      SET_PT_BOTH (clip_to_bounds (BEGV, ex->point.charpos, ZV),
-                   clip_to_bounds (BEGV_BYTE, ex->point.bytepos, ZV_BYTE));
-      unchain_marker (&ex->point);
-
-      /* Restore mark if it was non-zero.  */
-      m = XMARKER (BVAR (b, mark));
-      oldpos = m->charpos;
-      if (BEGV <= ex->mark.charpos)
-        attach_marker (m, b, ex->mark.charpos, ex->mark.bytepos);
-      newpos = ex->mark.charpos;
-      unchain_marker (&ex->mark);
-
-      /* If mark and region was active, restore them.  */
-      active = !NILP (BVAR (b, mark_active));
-      BVAR (b, mark_active) = ex->active ? Qt : Qnil;
-
-      /* If mark is active now, and either was not active
-         or was at a different place, run the activate hook.  */
-      if (ex->active && oldpos != newpos)
-        {
-          obj = intern ("activate-mark-hook");
-          Frun_hooks (1, &obj);
-        }
-      /* If mark has ceased to be active, run deactivate hook.  */
-      else if (active)
-        {
-          obj = intern ("deactivate-mark-hook");
-          Frun_hooks (1, &obj);
-        }
-
-      /* If buffer was visible in a window, and a different window
-         was selected, and the old selected window is still showing
-         this buffer, restore point in that window.  */
-      if (ex->visible)
-        {
-          struct window *w = ex->window;
-
-          if (w != XWINDOW (selected_window) && XBUFFER (w->buffer) == b)
-            attach_marker (XMARKER (w->pointm), b, PT, PT_BYTE);
-        }
+      if (! EQ (omark, nmark))
+        {
+          tem = intern ("activate-mark-hook");
+          Frun_hooks (1, &tem);
+        }
+    }
+  /* If mark has ceased to be active, run deactivate hook.  */
+  else if (! NILP (tem1))
+    {
+      tem = intern ("deactivate-mark-hook");
+      Frun_hooks (1, &tem);
     }
 
-  xfree (ex);
+  /* If buffer was visible in a window, and a different window was
+     selected, and the old selected window is still showing this
+     buffer, restore point in that window.  */
+  tem = XCDR (info);
+  if (visible_p
+      && !EQ (tem, selected_window)
+      && (tem1 = XWINDOW (tem)->buffer,
+          (/* Window is live...  */
+           BUFFERP (tem1)
+           /* ...and it shows the current buffer.  */
+           && XBUFFER (tem1) == current_buffer)))
+    Fset_window_point (tem, make_number (PT));
+
+  UNGCPRO;
   return Qnil;
 }
 
diff --git a/src/lisp.h b/src/lisp.h
index dd03a130c7c..f0129f05efd 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -375,7 +375,6 @@ enum pvec_type
   PVEC_TERMINAL,
   PVEC_WINDOW_CONFIGURATION,
   PVEC_SUBR,
-  PVEC_EXCURSION,
   PVEC_OTHER,
   /* These last 4 are special because we OR them in fns.c:internal_equal,
      so they have to use a disjoint bit pattern:
@@ -545,8 +544,6 @@ clip_to_bounds (ptrdiff_t lower, EMACS_INT num, ptrdiff_t upper)
                       (struct terminal *) XUNTAG (a, Lisp_Vectorlike))
 #define XSUBR(a) (eassert (SUBRP (a)), \
                   (struct Lisp_Subr *) XUNTAG (a, Lisp_Vectorlike))
-#define XEXCURSION(a) (eassert (EXCURSIONP (a)), \
-                       (struct Lisp_Excursion *) XUNTAG (a, Lisp_Vectorlike))
 #define XBUFFER(a) (eassert (BUFFERP (a)), \
                     (struct buffer *) XUNTAG (a, Lisp_Vectorlike))
 #define XCHAR_TABLE(a) (eassert (CHAR_TABLE_P (a)), \
@@ -599,12 +596,9 @@ clip_to_bounds (ptrdiff_t lower, EMACS_INT num, ptrdiff_t upper)
 #define XSETPROCESS(a, b) (XSETPSEUDOVECTOR (a, b, PVEC_PROCESS))
 #define XSETWINDOW(a, b) (XSETPSEUDOVECTOR (a, b, PVEC_WINDOW))
 #define XSETTERMINAL(a, b) (XSETPSEUDOVECTOR (a, b, PVEC_TERMINAL))
-/* These are special because both Lisp_Subr and Lisp_Excursion lacks
-   struct vectorlike_header.  */
+/* XSETSUBR is special since Lisp_Subr lacks struct vectorlike_header.  */
 #define XSETSUBR(a, b) \
   XSETTYPED_PSEUDOVECTOR (a, b, XSUBR (a)->size, PVEC_SUBR)
-#define XSETEXCURSION(a, b) \
-  XSETTYPED_PSEUDOVECTOR (a, b, XEXCURSION (a)->size, PVEC_EXCURSION)
 #define XSETCOMPILED(a, b) (XSETPSEUDOVECTOR (a, b, PVEC_COMPILED))
 #define XSETBUFFER(a, b) (XSETPSEUDOVECTOR (a, b, PVEC_BUFFER))
 #define XSETCHAR_TABLE(a, b) (XSETPSEUDOVECTOR (a, b, PVEC_CHAR_TABLE))
@@ -1521,33 +1515,6 @@ struct Lisp_Float
 #define XFLOAT_INIT(f,n) (XFLOAT (f)->u.data = (n))
 #endif
 
-/* This structure is used to record buffer state for Fsave_excursion.
-   It's mostly treated as Lisp_Vector but allocated and freed explicitly
-   with xmalloc and xfree, so there is no vectorlike_header here.  */
-
-struct Lisp_Excursion
-{
-  ptrdiff_t size;
-
-  /* Saved value of XWINDOW (selected_window).  */
-  struct window *window;
-
-  /* Buffer where this excursion is in effect.  */
-  struct buffer *buffer;
-
-  /* Non-zero if the window above has displayed the buffer.  */
-  unsigned visible : 1;
-
-  /* Non-zero if this buffer has the mark active.  */
-  unsigned active : 1;
-
-  /* Saved point.  */
-  struct Lisp_Marker point;
-
-  /* Saved mark.  May point to nowhere.  */
-  struct Lisp_Marker mark;
-};
-
 /* A character, declared with the following typedef, is a member
    of some character set associated with the current buffer.  */
 #ifndef _UCHAR_T  /* Protect against something in ctab.h on AIX.  */
@@ -1730,10 +1697,8 @@ typedef struct {
 #define PROCESSP(x) PSEUDOVECTORP (x, PVEC_PROCESS)
 #define WINDOWP(x) PSEUDOVECTORP (x, PVEC_WINDOW)
 #define TERMINALP(x) PSEUDOVECTORP (x, PVEC_TERMINAL)
-/* These are special because both Lisp_Subr and Lisp_Excursion lacks
-   struct vectorlike_header.  */
+/* SUBRP is special since Lisp_Subr lacks struct vectorlike_header.  */
 #define SUBRP(x) TYPED_PSEUDOVECTORP (x, Lisp_Subr, PVEC_SUBR)
-#define EXCURSIONP(x) TYPED_PSEUDOVECTORP (x, Lisp_Excursion, PVEC_EXCURSION)
 #define COMPILEDP(x) PSEUDOVECTORP (x, PVEC_COMPILED)
 #define BUFFERP(x) PSEUDOVECTORP (x, PVEC_BUFFER)
 #define CHAR_TABLE_P(x) PSEUDOVECTORP (x, PVEC_CHAR_TABLE)
@@ -2949,15 +2914,11 @@ extern void clear_charpos_cache (struct buffer *);
 extern ptrdiff_t charpos_to_bytepos (ptrdiff_t);
 extern ptrdiff_t buf_charpos_to_bytepos (struct buffer *, ptrdiff_t);
 extern ptrdiff_t buf_bytepos_to_charpos (struct buffer *, ptrdiff_t);
-extern void unchain_marker (struct Lisp_Marker *);
+extern void unchain_marker (struct Lisp_Marker *marker);
 extern Lisp_Object set_marker_restricted (Lisp_Object, Lisp_Object, Lisp_Object);
 extern Lisp_Object set_marker_both (Lisp_Object, Lisp_Object, ptrdiff_t, ptrdiff_t);
 extern Lisp_Object set_marker_restricted_both (Lisp_Object, Lisp_Object,
-                                               ptrdiff_t, ptrdiff_t);
-extern void init_marker (struct Lisp_Marker *, struct buffer *,
-                         ptrdiff_t, ptrdiff_t, int);
-extern void attach_marker (struct Lisp_Marker *, struct buffer *,
-                           ptrdiff_t, ptrdiff_t);
+                                               ptrdiff_t, ptrdiff_t);
 extern Lisp_Object build_marker (struct buffer *, ptrdiff_t, ptrdiff_t);
 extern void syms_of_marker (void);
 
diff --git a/src/marker.c b/src/marker.c
index d63947d8c31..0a93f4c180f 100644
--- a/src/marker.c
+++ b/src/marker.c
@@ -425,28 +425,9 @@ Returns nil if MARKER points nowhere.  */)
   return Qnil;
 }
 
-/* Initialize just allocated Lisp_Marker.  */
-
-void
-init_marker (struct Lisp_Marker *m, struct buffer *b,
-             ptrdiff_t charpos, ptrdiff_t bytepos, int type)
-{
-  m->buffer = b;
-  m->charpos = charpos;
-  m->bytepos = bytepos;
-  m->insertion_type = type;
-  if (b)
-    {
-      m->next = BUF_MARKERS (b);
-      BUF_MARKERS (b) = m;
-    }
-  else
-    m->next = NULL;
-}
-
 /* Change M so it points to B at CHARPOS and BYTEPOS.  */
 
-void
+static inline void
 attach_marker (struct Lisp_Marker *m, struct buffer *b,
                ptrdiff_t charpos, ptrdiff_t bytepos)
 {