Backport fix for Bug#8219 from trunk.

* buffer.h (BUF_BEGV, BUF_BEGV_BYTE, BUF_ZV, BUF_ZV_BYTE, BUF_PT)
(BUF_PT_BYTE): Rewrite to handle indirect buffers (Bug#8219).
These macros can no longer be used for assignment.

* buffer.c (Fget_buffer_create, Fmake_indirect_buffer): Assign
struct members directly, instead of using BUF_BEGV etc.
(record_buffer_markers, fetch_buffer_markers): New functions for
recording and fetching special buffer markers.
(set_buffer_internal_1, set_buffer_temp): Use them.

* lread.c (unreadchar): Use SET_BUF_PT_BOTH.

* insdel.c (adjust_point): Use SET_BUF_PT_BOTH.

* intervals.c (temp_set_point_both): Use SET_BUF_PT_BOTH.
(get_local_map): Use SET_BUF_BEGV_BOTH and SET_BUF_ZV_BOTH.

* xdisp.c (hscroll_window_tree):
(reconsider_clip_changes): Use PT instead of BUF_PT.

7 files changed, 148 insertions, 133 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 49b37a843b6..be81dd27584 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,25 @@
+2011-03-19  Chong Yidong  <cyd@stupidchicken.com>
+
+        * buffer.h (BUF_BEGV, BUF_BEGV_BYTE, BUF_ZV, BUF_ZV_BYTE, BUF_PT)
+        (BUF_PT_BYTE): Rewrite to handle indirect buffers (Bug#8219).
+        These macros can no longer be used for assignment.
+
+        * buffer.c (Fget_buffer_create, Fmake_indirect_buffer): Assign
+        struct members directly, instead of using BUF_BEGV etc.
+        (record_buffer_markers, fetch_buffer_markers): New functions for
+        recording and fetching special buffer markers.
+        (set_buffer_internal_1, set_buffer_temp): Use them.
+
+        * lread.c (unreadchar): Use SET_BUF_PT_BOTH.
+
+        * insdel.c (adjust_point): Use SET_BUF_PT_BOTH.
+
+        * intervals.c (temp_set_point_both): Use SET_BUF_PT_BOTH.
+        (get_local_map): Use SET_BUF_BEGV_BOTH and SET_BUF_ZV_BOTH.
+
+        * xdisp.c (hscroll_window_tree):
+        (reconsider_clip_changes): Use PT instead of BUF_PT.
+
 2011-03-17  Juanma Barranquero  <lekktu@gmail.com>
 
         * xfaces.c (Fx_load_color_file):
diff --git a/src/buffer.c b/src/buffer.c
index 9220527313d..e7759cb5255 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -371,15 +371,17 @@ even if it is dead.  The return value is never nil.  */)
   if (! BUF_BEG_ADDR (b))
     buffer_memory_full ();
 
-  BUF_PT (b) = BEG;
+  b->pt = BEG;
+  b->begv = BEG;
+  b->zv = BEG;
+  b->pt_byte = BEG_BYTE;
+  b->begv_byte = BEG_BYTE;
+  b->zv_byte = BEG_BYTE;
+
   BUF_GPT (b) = BEG;
-  BUF_BEGV (b) = BEG;
-  BUF_ZV (b) = BEG;
-  BUF_Z (b) = BEG;
-  BUF_PT_BYTE (b) = BEG_BYTE;
   BUF_GPT_BYTE (b) = BEG_BYTE;
-  BUF_BEGV_BYTE (b) = BEG_BYTE;
-  BUF_ZV_BYTE (b) = BEG_BYTE;
+
+  BUF_Z (b) = BEG;
   BUF_Z_BYTE (b) = BEG_BYTE;
   BUF_MODIFF (b) = 1;
   BUF_CHARS_MODIFF (b) = 1;
@@ -533,6 +535,53 @@ clone_per_buffer_values (from, to)
   to->local_var_alist = buffer_lisp_local_variables (from);
 }
 
+
+/* If buffer B has markers to record PT, BEGV and ZV when it is not
+   current, update these markers.  */
+
+static void
+record_buffer_markers (struct buffer *b)
+{
+  if (! NILP (b->pt_marker))
+    {
+      Lisp_Object buffer;
+
+      eassert (!NILP (b->begv_marker));
+      eassert (!NILP (b->zv_marker));
+
+      XSETBUFFER (buffer, b);
+      set_marker_both (b->pt_marker, buffer, b->pt, b->pt_byte);
+      set_marker_both (b->begv_marker, buffer, b->begv, b->begv_byte);
+      set_marker_both (b->zv_marker, buffer, b->zv, b->zv_byte);
+    }
+}
+
+
+/* If buffer B has markers to record PT, BEGV and ZV when it is not
+   current, fetch these values into B->begv etc.  */
+
+static void
+fetch_buffer_markers (struct buffer *b)
+{
+  if (! NILP (b->pt_marker))
+    {
+      Lisp_Object m;
+
+      eassert (!NILP (b->begv_marker));
+      eassert (!NILP (b->zv_marker));
+
+      m = b->pt_marker;
+      SET_BUF_PT_BOTH (b, marker_position (m), marker_byte_position (m));
+
+      m = b->begv_marker;
+      SET_BUF_BEGV_BOTH (b, marker_position (m), marker_byte_position (m));
+
+      m = b->zv_marker;
+      SET_BUF_ZV_BOTH (b, marker_position (m), marker_byte_position (m));
+    }
+}
+
+
 DEFUN ("make-indirect-buffer", Fmake_indirect_buffer, Smake_indirect_buffer,
        2, 3,
        "bMake indirect buffer (to buffer): \nBName of indirect buffer: ",
@@ -572,12 +621,12 @@ CLONE nil means the indirect buffer's state is reset to default values.  */)
   /* Use the base buffer's text object.  */
   b->text = b->base_buffer->text;
 
-  BUF_BEGV (b) = BUF_BEGV (b->base_buffer);
-  BUF_ZV (b) = BUF_ZV (b->base_buffer);
-  BUF_PT (b) = BUF_PT (b->base_buffer);
-  BUF_BEGV_BYTE (b) = BUF_BEGV_BYTE (b->base_buffer);
-  BUF_ZV_BYTE (b) = BUF_ZV_BYTE (b->base_buffer);
-  BUF_PT_BYTE (b) = BUF_PT_BYTE (b->base_buffer);
+  b->pt = b->base_buffer->pt;
+  b->begv = b->base_buffer->begv;
+  b->zv = b->base_buffer->zv;
+  b->pt_byte = b->base_buffer->pt_byte;
+  b->begv_byte = b->base_buffer->begv_byte;
+  b->zv_byte = b->base_buffer->zv_byte;
 
   b->newline_cache = 0;
   b->width_run_cache = 0;
@@ -607,24 +656,23 @@ CLONE nil means the indirect buffer's state is reset to default values.  */)
   /* Make sure the base buffer has markers for its narrowing.  */
   if (NILP (b->base_buffer->pt_marker))
     {
+      eassert (NILP (b->base_buffer->begv_marker));
+      eassert (NILP (b->base_buffer->zv_marker));
+
       b->base_buffer->pt_marker = Fmake_marker ();
       set_marker_both (b->base_buffer->pt_marker, base_buffer,
-                       BUF_PT (b->base_buffer),
-                       BUF_PT_BYTE (b->base_buffer));
-    }
-  if (NILP (b->base_buffer->begv_marker))
-    {
+                       b->base_buffer->pt,
+                       b->base_buffer->pt_byte);
+
       b->base_buffer->begv_marker = Fmake_marker ();
       set_marker_both (b->base_buffer->begv_marker, base_buffer,
-                       BUF_BEGV (b->base_buffer),
-                       BUF_BEGV_BYTE (b->base_buffer));
-    }
-  if (NILP (b->base_buffer->zv_marker))
-    {
+                       b->base_buffer->begv,
+                       b->base_buffer->begv_byte);
+
       b->base_buffer->zv_marker = Fmake_marker ();
       set_marker_both (b->base_buffer->zv_marker, base_buffer,
-                       BUF_ZV (b->base_buffer),
-                       BUF_ZV_BYTE (b->base_buffer));
+                       b->base_buffer->zv,
+                       b->base_buffer->zv_byte);
       XMARKER (b->base_buffer->zv_marker)->insertion_type = 1;
     }
 
@@ -632,11 +680,11 @@ CLONE nil means the indirect buffer's state is reset to default values.  */)
     {
       /* Give the indirect buffer markers for its narrowing.  */
       b->pt_marker = Fmake_marker ();
-      set_marker_both (b->pt_marker, buf, BUF_PT (b), BUF_PT_BYTE (b));
+      set_marker_both (b->pt_marker, buf, b->pt, b->pt_byte);
       b->begv_marker = Fmake_marker ();
-      set_marker_both (b->begv_marker, buf, BUF_BEGV (b), BUF_BEGV_BYTE (b));
+      set_marker_both (b->begv_marker, buf, b->begv, b->begv_byte);
       b->zv_marker = Fmake_marker ();
-      set_marker_both (b->zv_marker, buf, BUF_ZV (b), BUF_ZV_BYTE (b));
+      set_marker_both (b->zv_marker, buf, b->zv, b->zv_byte);
       XMARKER (b->zv_marker)->insertion_type = 1;
     }
   else
@@ -1890,27 +1938,7 @@ set_buffer_internal_1 (b)
 
       /* If the old current buffer has markers to record PT, BEGV and ZV
          when it is not current, update them now.  */
-      if (! NILP (old_buf->pt_marker))
-        {
-          Lisp_Object obuf;
-          XSETBUFFER (obuf, old_buf);
-          set_marker_both (old_buf->pt_marker, obuf,
-                           BUF_PT (old_buf), BUF_PT_BYTE (old_buf));
-        }
-      if (! NILP (old_buf->begv_marker))
-        {
-          Lisp_Object obuf;
-          XSETBUFFER (obuf, old_buf);
-          set_marker_both (old_buf->begv_marker, obuf,
-                           BUF_BEGV (old_buf), BUF_BEGV_BYTE (old_buf));
-        }
-      if (! NILP (old_buf->zv_marker))
-        {
-          Lisp_Object obuf;
-          XSETBUFFER (obuf, old_buf);
-          set_marker_both (old_buf->zv_marker, obuf,
-                           BUF_ZV (old_buf), BUF_ZV_BYTE (old_buf));
-        }
+      record_buffer_markers (old_buf);
     }
 
   /* Get the undo list from the base buffer, so that it appears
@@ -1920,21 +1948,7 @@ set_buffer_internal_1 (b)
 
   /* If the new current buffer has markers to record PT, BEGV and ZV
      when it is not current, fetch them now.  */
-  if (! NILP (b->pt_marker))
-    {
-      BUF_PT (b) = marker_position (b->pt_marker);
-      BUF_PT_BYTE (b) = marker_byte_position (b->pt_marker);
-    }
-  if (! NILP (b->begv_marker))
-    {
-      BUF_BEGV (b) = marker_position (b->begv_marker);
-      BUF_BEGV_BYTE (b) = marker_byte_position (b->begv_marker);
-    }
-  if (! NILP (b->zv_marker))
-    {
-      BUF_ZV (b) = marker_position (b->zv_marker);
-      BUF_ZV_BYTE (b) = marker_byte_position (b->zv_marker);
-    }
+  fetch_buffer_markers (b);
 
   /* Look down buffer's list of local Lisp variables
      to find and update any that forward into C variables. */
@@ -1984,50 +1998,13 @@ set_buffer_temp (b)
   old_buf = current_buffer;
   current_buffer = b;
 
-  if (old_buf)
-    {
-      /* If the old current buffer has markers to record PT, BEGV and ZV
-         when it is not current, update them now.  */
-      if (! NILP (old_buf->pt_marker))
-        {
-          Lisp_Object obuf;
-          XSETBUFFER (obuf, old_buf);
-          set_marker_both (old_buf->pt_marker, obuf,
-                           BUF_PT (old_buf), BUF_PT_BYTE (old_buf));
-        }
-      if (! NILP (old_buf->begv_marker))
-        {
-          Lisp_Object obuf;
-          XSETBUFFER (obuf, old_buf);
-          set_marker_both (old_buf->begv_marker, obuf,
-                           BUF_BEGV (old_buf), BUF_BEGV_BYTE (old_buf));
-        }
-      if (! NILP (old_buf->zv_marker))
-        {
-          Lisp_Object obuf;
-          XSETBUFFER (obuf, old_buf);
-          set_marker_both (old_buf->zv_marker, obuf,
-                           BUF_ZV (old_buf), BUF_ZV_BYTE (old_buf));
-        }
-    }
+  /* If the old current buffer has markers to record PT, BEGV and ZV
+     when it is not current, update them now.  */
+  record_buffer_markers (old_buf);
 
   /* If the new current buffer has markers to record PT, BEGV and ZV
      when it is not current, fetch them now.  */
-  if (! NILP (b->pt_marker))
-    {
-      BUF_PT (b) = marker_position (b->pt_marker);
-      BUF_PT_BYTE (b) = marker_byte_position (b->pt_marker);
-    }
-  if (! NILP (b->begv_marker))
-    {
-      BUF_BEGV (b) = marker_position (b->begv_marker);
-      BUF_BEGV_BYTE (b) = marker_byte_position (b->begv_marker);
-    }
-  if (! NILP (b->zv_marker))
-    {
-      BUF_ZV (b) = marker_position (b->zv_marker);
-      BUF_ZV_BYTE (b) = marker_byte_position (b->zv_marker);
-    }
+  fetch_buffer_markers (b);
 }
 
 DEFUN ("set-buffer", Fset_buffer, Sset_buffer, 1, 1, 0,
diff --git a/src/buffer.h b/src/buffer.h
index 21854571670..56d0422b7e3 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -107,22 +107,46 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #define BUF_BEG(buf) (BEG)
 #define BUF_BEG_BYTE(buf) (BEG_BYTE)
 
+/* The BUF_BEGV[_BYTE], BUF_ZV[_BYTE], and BUF_PT[_BYTE] macros cannot
+   be used for assignment; use SET_BUF_* macros below for that.  */
+
 /* Position of beginning of accessible range of buffer.  */
-#define BUF_BEGV(buf) ((buf)->begv)
-#define BUF_BEGV_BYTE(buf) ((buf)->begv_byte)
+#define BUF_BEGV(buf)                                   \
+   (buf == current_buffer ? BEGV                        \
+    : NILP (buf->begv_marker) ? buf->begv               \
+    : marker_position (buf->begv_marker))
+
+#define BUF_BEGV_BYTE(buf)                              \
+   (buf == current_buffer ? BEGV_BYTE                   \
+    : NILP (buf->begv_marker) ? buf->begv_byte          \
+    : marker_byte_position (buf->begv_marker))
 
 /* Position of point in buffer.  */
-#define BUF_PT(buf) ((buf)->pt)
-#define BUF_PT_BYTE(buf) ((buf)->pt_byte)
+#define BUF_PT(buf)                                     \
+   (buf == current_buffer ? PT                          \
+    : NILP (buf->pt_marker) ? buf->pt                   \
+    : marker_position (buf->pt_marker))
+
+#define BUF_PT_BYTE(buf)                                \
+   (buf == current_buffer ? PT_BYTE                     \
+    : NILP (buf->pt_marker) ? buf->pt_byte              \
+    : marker_byte_position (buf->pt_marker))
+
+/* Position of end of accessible range of buffer.  */
+#define BUF_ZV(buf)                                     \
+   (buf == current_buffer ? ZV                          \
+    : NILP (buf->zv_marker) ? buf->zv                   \
+    : marker_position (buf->zv_marker))
+
+#define BUF_ZV_BYTE(buf)                                \
+   (buf == current_buffer ? ZV_BYTE                     \
+    : NILP (buf->zv_marker) ? buf->zv_byte              \
+    : marker_byte_position (buf->zv_marker))
 
 /* Position of gap in buffer.  */
 #define BUF_GPT(buf) ((buf)->text->gpt)
 #define BUF_GPT_BYTE(buf) ((buf)->text->gpt_byte)
 
-/* Position of end of accessible range of buffer.  */
-#define BUF_ZV(buf) ((buf)->zv)
-#define BUF_ZV_BYTE(buf) ((buf)->zv_byte)
-
 /* Position of end of buffer.  */
 #define BUF_Z(buf) ((buf)->text->z)
 #define BUF_Z_BYTE(buf) ((buf)->text->z_byte)
@@ -230,8 +254,6 @@ extern void enlarge_buffer_text P_ ((struct buffer *, EMACS_INT));
 
 /* Macros for setting the BEGV, ZV or PT of a given buffer.
 
-   SET_BUF_PT* seet to be redundant.  Get rid of them?
-
    The ..._BOTH macros take both a charpos and a bytepos,
    which must correspond to each other.
 
diff --git a/src/insdel.c b/src/insdel.c
index 7e0ba797fa8..b76a2d2271a 100644
--- a/src/insdel.c
+++ b/src/insdel.c
@@ -459,9 +459,7 @@ adjust_markers_for_insert (EMACS_INT from, EMACS_INT from_byte,
 static void
 adjust_point (EMACS_INT nchars, EMACS_INT nbytes)
 {
-  BUF_PT (current_buffer) += nchars;
-  BUF_PT_BYTE (current_buffer) += nbytes;
-
+  SET_BUF_PT_BOTH (current_buffer, PT + nchars, PT_BYTE + nbytes);
   /* In a single-byte buffer, the two positions must be equal.  */
   eassert (PT_BYTE >= PT && PT_BYTE - PT <= ZV_BYTE - ZV);
 }
diff --git a/src/intervals.c b/src/intervals.c
index d47888b237c..fd8f3f55479 100644
--- a/src/intervals.c
+++ b/src/intervals.c
@@ -1949,8 +1949,7 @@ temp_set_point_both (struct buffer *buffer,
   if (charpos > BUF_ZV (buffer) || charpos < BUF_BEGV (buffer))
     abort ();
 
-  BUF_PT_BYTE (buffer) = bytepos;
-  BUF_PT (buffer) = charpos;
+  SET_BUF_PT_BOTH (buffer, charpos, bytepos);
 }
 
 /* Set point in BUFFER to CHARPOS.  If the target position is
@@ -2366,10 +2365,9 @@ get_local_map (position, buffer, type)
   old_zv = BUF_ZV (buffer);
   old_begv_byte = BUF_BEGV_BYTE (buffer);
   old_zv_byte = BUF_ZV_BYTE (buffer);
-  BUF_BEGV (buffer) = BUF_BEG (buffer);
-  BUF_ZV (buffer) = BUF_Z (buffer);
-  BUF_BEGV_BYTE (buffer) = BUF_BEG_BYTE (buffer);
-  BUF_ZV_BYTE (buffer) = BUF_Z_BYTE (buffer);
+
+  SET_BUF_BEGV_BOTH (buffer, BUF_BEG (buffer), BUF_BEG_BYTE (buffer));
+  SET_BUF_ZV_BOTH (buffer, BUF_Z (buffer), BUF_Z_BYTE (buffer));
 
   XSETFASTINT (lispy_position, position);
   XSETBUFFER (lispy_buffer, buffer);
@@ -2383,10 +2381,8 @@ get_local_map (position, buffer, type)
   if (NILP (prop))
     prop = get_pos_property (lispy_position, type, lispy_buffer);
 
-  BUF_BEGV (buffer) = old_begv;
-  BUF_ZV (buffer) = old_zv;
-  BUF_BEGV_BYTE (buffer) = old_begv_byte;
-  BUF_ZV_BYTE (buffer) = old_zv_byte;
+  SET_BUF_BEGV_BOTH (buffer, old_begv, old_begv_byte);
+  SET_BUF_ZV_BOTH (buffer, old_zv, old_zv_byte);
 
   /* Use the local map only if it is valid.  */
   prop = get_keymap (prop, 0, 0);
diff --git a/src/lread.c b/src/lread.c
index 8f1d4af8f36..2da64632417 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -458,15 +458,15 @@ unreadchar (readcharfun, c)
   else if (BUFFERP (readcharfun))
     {
       struct buffer *b = XBUFFER (readcharfun);
-      int bytepos = BUF_PT_BYTE (b);
+      EMACS_INT charpos = BUF_PT (b);
+      EMACS_INT bytepos = BUF_PT_BYTE (b);
 
-      BUF_PT (b)--;
       if (! NILP (b->enable_multibyte_characters))
         BUF_DEC_POS (b, bytepos);
       else
         bytepos--;
 
-      BUF_PT_BYTE (b) = bytepos;
+      SET_BUF_PT_BOTH (b, charpos - 1, bytepos);
     }
   else if (MARKERP (readcharfun))
     {
diff --git a/src/xdisp.c b/src/xdisp.c
index c2af4d68b6e..ade95cf3d62 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -10760,7 +10760,7 @@ hscroll_window_tree (window)
               current_buffer = XBUFFER (w->buffer);
 
               if (w == XWINDOW (selected_window))
-                pt = BUF_PT (current_buffer);
+                pt = PT;
               else
                 {
                   pt = marker_position (w->pointm);
@@ -11194,7 +11194,7 @@ reconsider_clip_changes (w, b)
       int pt;
 
       if (w == XWINDOW (selected_window))
-        pt = BUF_PT (current_buffer);
+        pt = PT;
       else
         pt = marker_position (w->pointm);