New macro to iterate over all buffers, miscellaneous cleanups.

* lisp.h (all_buffers): Remove declaration.
* buffer.h (all_buffers): Add declaration, with comment.
(for_each_buffer): New macro.
* alloc.c (Fgarbage_collect, mark_object): Use it.
* buffer.c (Fkill_buffer, Fbuffer_swap_text, Fset_buffer_multibyte)
(init_buffer): Likewise.
* data.c (Fset_default): Likewise.
* coding.c (code_conversion_restore): Remove redundant check
for dead buffer.
* buffer.c (Fkill_buffer): Likewise.  Remove obsolete comment.

7 files changed, 98 insertions, 89 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 5a7a981926b..73632c26bff 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,17 @@
+2012-07-19  Dmitry Antipov  <dmantipov@yandex.ru>
+
+        New macro to iterate over all buffers, miscellaneous cleanups.
+        * lisp.h (all_buffers): Remove declaration.
+        * buffer.h (all_buffers): Add declaration, with comment.
+        (for_each_buffer): New macro.
+        * alloc.c (Fgarbage_collect, mark_object): Use it.
+        * buffer.c (Fkill_buffer, Fbuffer_swap_text, Fset_buffer_multibyte)
+        (init_buffer): Likewise.
+        * data.c (Fset_default): Likewise.
+        * coding.c (code_conversion_restore): Remove redundant check
+        for dead buffer.
+        * buffer.c (Fkill_buffer): Likewise.  Remove obsolete comment.
+
 2012-07-18  Andreas Schwab  <schwab@linux-m68k.org>
 
         Fix bug that created negative-length intervals.
@@ -110,7 +124,6 @@
         * gnutls.c (emacs_gnutls_handshake): Only retry if
         GNUTLS_E_INTERRUPTED.
 
-2012-07-17  Eli Zaretskii  <eliz@gnu.org>
 2012-07-17  Dmitry Antipov  <dmantipov@yandex.ru>
 
         Cleanup and convert miscellaneous checks to eassert.
diff --git a/src/alloc.c b/src/alloc.c
index a6980e867a7..166f5b72449 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -5392,6 +5392,7 @@ See Info node `(elisp)Garbage Collection'.  */)
   (void)
 {
   register struct specbinding *bind;
+  register struct buffer *nextb;
   char stack_top_variable;
   ptrdiff_t i;
   int message_p;
@@ -5411,40 +5412,34 @@ See Info node `(elisp)Garbage Collection'.  */)
 
   /* Don't keep undo information around forever.
      Do this early on, so it is no problem if the user quits.  */
-  {
-    register struct buffer *nextb = all_buffers;
-
-    while (nextb)
-      {
-        /* If a buffer's undo list is Qt, that means that undo is
-           turned off in that buffer.  Calling truncate_undo_list on
-           Qt tends to return NULL, which effectively turns undo back on.
-           So don't call truncate_undo_list if undo_list is Qt.  */
-        if (! NILP (nextb->BUFFER_INTERNAL_FIELD (name))
-            && ! EQ (nextb->BUFFER_INTERNAL_FIELD (undo_list), Qt))
-          truncate_undo_list (nextb);
-
-        /* Shrink buffer gaps, but skip indirect and dead buffers.  */
-        if (nextb->base_buffer == 0 && !NILP (nextb->BUFFER_INTERNAL_FIELD (name))
-            && ! nextb->text->inhibit_shrinking)
-          {
-            /* If a buffer's gap size is more than 10% of the buffer
-               size, or larger than 2000 bytes, then shrink it
-               accordingly.  Keep a minimum size of 20 bytes.  */
-            int size = min (2000, max (20, (nextb->text->z_byte / 10)));
-
-            if (nextb->text->gap_size > size)
-              {
-                struct buffer *save_current = current_buffer;
-                current_buffer = nextb;
-                make_gap (-(nextb->text->gap_size - size));
-                current_buffer = save_current;
-              }
-          }
+  for_each_buffer (nextb)
+    {
+      /* If a buffer's undo list is Qt, that means that undo is
+         turned off in that buffer.  Calling truncate_undo_list on
+         Qt tends to return NULL, which effectively turns undo back on.
+         So don't call truncate_undo_list if undo_list is Qt.  */
+      if (! NILP (nextb->BUFFER_INTERNAL_FIELD (name))
+          && ! EQ (nextb->BUFFER_INTERNAL_FIELD (undo_list), Qt))
+        truncate_undo_list (nextb);
+
+      /* Shrink buffer gaps, but skip indirect and dead buffers.  */
+      if (nextb->base_buffer == 0 && !NILP (nextb->BUFFER_INTERNAL_FIELD (name))
+          && ! nextb->text->inhibit_shrinking)
+        {
+          /* If a buffer's gap size is more than 10% of the buffer
+             size, or larger than 2000 bytes, then shrink it
+             accordingly.  Keep a minimum size of 20 bytes.  */
+          int size = min (2000, max (20, (nextb->text->z_byte / 10)));
 
-        nextb = nextb->header.next.buffer;
-      }
-  }
+          if (nextb->text->gap_size > size)
+            {
+              struct buffer *save_current = current_buffer;
+              current_buffer = nextb;
+              make_gap (-(nextb->text->gap_size - size));
+              current_buffer = save_current;
+            }
+        }
+    }
 
   t1 = current_emacs_time ();
 
@@ -5558,48 +5553,42 @@ See Info node `(elisp)Garbage Collection'.  */)
      Look thru every buffer's undo list
      for elements that update markers that were not marked,
      and delete them.  */
-  {
-    register struct buffer *nextb = all_buffers;
-
-    while (nextb)
-      {
-        /* If a buffer's undo list is Qt, that means that undo is
-           turned off in that buffer.  Calling truncate_undo_list on
-           Qt tends to return NULL, which effectively turns undo back on.
-           So don't call truncate_undo_list if undo_list is Qt.  */
-        if (! EQ (nextb->BUFFER_INTERNAL_FIELD (undo_list), Qt))
-          {
-            Lisp_Object tail, prev;
-            tail = nextb->BUFFER_INTERNAL_FIELD (undo_list);
-            prev = Qnil;
-            while (CONSP (tail))
-              {
-                if (CONSP (XCAR (tail))
-                    && MARKERP (XCAR (XCAR (tail)))
-                    && !XMARKER (XCAR (XCAR (tail)))->gcmarkbit)
-                  {
-                    if (NILP (prev))
-                      nextb->BUFFER_INTERNAL_FIELD (undo_list) = tail = XCDR (tail);
-                    else
-                      {
-                        tail = XCDR (tail);
-                        XSETCDR (prev, tail);
-                      }
-                  }
-                else
-                  {
-                    prev = tail;
-                    tail = XCDR (tail);
-                  }
-              }
-          }
-        /* Now that we have stripped the elements that need not be in the
-           undo_list any more, we can finally mark the list.  */
-        mark_object (nextb->BUFFER_INTERNAL_FIELD (undo_list));
-
-        nextb = nextb->header.next.buffer;
-      }
-  }
+  for_each_buffer (nextb)
+    {
+      /* If a buffer's undo list is Qt, that means that undo is
+         turned off in that buffer.  Calling truncate_undo_list on
+         Qt tends to return NULL, which effectively turns undo back on.
+         So don't call truncate_undo_list if undo_list is Qt.  */
+      if (! EQ (nextb->BUFFER_INTERNAL_FIELD (undo_list), Qt))
+        {
+          Lisp_Object tail, prev;
+          tail = nextb->BUFFER_INTERNAL_FIELD (undo_list);
+          prev = Qnil;
+          while (CONSP (tail))
+            {
+              if (CONSP (XCAR (tail))
+                  && MARKERP (XCAR (XCAR (tail)))
+                  && !XMARKER (XCAR (XCAR (tail)))->gcmarkbit)
+                {
+                  if (NILP (prev))
+                    nextb->BUFFER_INTERNAL_FIELD (undo_list) = tail = XCDR (tail);
+                  else
+                    {
+                      tail = XCDR (tail);
+                      XSETCDR (prev, tail);
+                    }
+                }
+              else
+                {
+                  prev = tail;
+                  tail = XCDR (tail);
+                }
+            }
+        }
+      /* Now that we have stripped the elements that need not be in the
+         undo_list any more, we can finally mark the list.  */
+      mark_object (nextb->BUFFER_INTERNAL_FIELD (undo_list));
+    }
 
   gc_sweep ();
 
@@ -5987,9 +5976,10 @@ mark_object (Lisp_Object arg)
 #ifdef GC_CHECK_MARKED_OBJECTS
             if (po != &buffer_defaults && po != &buffer_local_symbols)
               {
-                struct buffer *b = all_buffers;
-                for (; b && b != po; b = b->header.next.buffer)
-                  ;
+                struct buffer *b;
+                for_each_buffer (b)
+                  if (b == po)
+                    break;
                 if (b == NULL)
                   abort ();
               }
diff --git a/src/buffer.c b/src/buffer.c
index 1e1bd933f93..40370460b9f 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -1532,10 +1532,8 @@ cleaning up all windows currently displaying the buffer to be killed. */)
 
       GCPRO1 (buffer);
 
-      for (other = all_buffers; other; other = other->header.next.buffer)
-        /* all_buffers contains dead buffers too;
-           don't re-kill them.  */
-        if (other->base_buffer == b && !NILP (BVAR (other, name)))
+      for_each_buffer (other)
+        if (other->base_buffer == b)
           {
             Lisp_Object buf;
             XSETBUFFER (buf, other);
@@ -2052,7 +2050,7 @@ DEFUN ("buffer-swap-text", Fbuffer_swap_text, Sbuffer_swap_text,
 
   { /* This is probably harder to make work.  */
     struct buffer *other;
-    for (other = all_buffers; other; other = other->header.next.buffer)
+    for_each_buffer (other)
       if (other->base_buffer == other_buffer
           || other->base_buffer == current_buffer)
         error ("One of the buffers to swap has indirect buffers");
@@ -2429,7 +2427,7 @@ current buffer is cleared.  */)
 
   /* Copy this buffer's new multibyte status
      into all of its indirect buffers.  */
-  for (other = all_buffers; other; other = other->header.next.buffer)
+  for_each_buffer (other)
     if (other->base_buffer == current_buffer && !NILP (BVAR (other, name)))
       {
         BVAR (other, enable_multibyte_characters)
@@ -5035,7 +5033,7 @@ init_buffer (void)
       Map new memory.  */
    struct buffer *b;
 
-   for (b = all_buffers; b; b = b->header.next.buffer)
+   for_each_buffer (b)
      if (b->text->beg == NULL)
        enlarge_buffer_text (b, 0);
  }
diff --git a/src/buffer.h b/src/buffer.h
index 4003be5c8c4..8c596835fcc 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -857,6 +857,15 @@ struct buffer
 };
 
 
+/* Chain of all buffers, including killed ones.  */
+
+extern struct buffer *all_buffers;
+
+/* Used to iterate over the chain above.  */
+
+#define for_each_buffer(b) \
+  for ((b) = all_buffers; (b); (b) = (b)->header.next.buffer)
+
 /* This points to the current buffer.  */
 
 extern struct buffer *current_buffer;
diff --git a/src/coding.c b/src/coding.c
index d9fcc634b77..212eb8275fe 100644
--- a/src/coding.c
+++ b/src/coding.c
@@ -7588,7 +7588,7 @@ code_conversion_restore (Lisp_Object arg)
     {
       if (EQ (workbuf, Vcode_conversion_reused_workbuf))
         reused_workbuf_in_use = 0;
-      else if (! NILP (Fbuffer_live_p (workbuf)))
+      else
         Fkill_buffer (workbuf);
     }
   set_buffer_internal (XBUFFER (current));
diff --git a/src/data.c b/src/data.c
index 22546349677..84bd347b136 100644
--- a/src/data.c
+++ b/src/data.c
@@ -1401,7 +1401,7 @@ for this variable.  */)
               {
                 struct buffer *b;
 
-                for (b = all_buffers; b; b = b->header.next.buffer)
+                for_each_buffer (b)
                   if (!PER_BUFFER_VALUE_P (b, idx))
                     PER_BUFFER_VALUE (b, offset) = value;
               }
diff --git a/src/lisp.h b/src/lisp.h
index 4dd9f37ca66..bfdc4ea4c07 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -2858,7 +2858,6 @@ extern Lisp_Object set_buffer_if_live (Lisp_Object);
 extern Lisp_Object other_buffer_safely (Lisp_Object);
 extern Lisp_Object Qpriority, Qwindow, Qbefore_string, Qafter_string;
 extern Lisp_Object get_truename_buffer (Lisp_Object);
-extern struct buffer *all_buffers;
 extern void init_buffer_once (void);
 extern void init_buffer (void);
 extern void syms_of_buffer (void);