Refactor getting the first element into a separate function.

 src/xdisp.c (get_visually_first_element): New function, refactored
 from common parts of next_element_from_buffer, next_element_from_string,
 and next_element_from_c_string.

2 files changed, 108 insertions, 141 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 315ac040d41..ba829af4026 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -3,6 +3,9 @@
         * xdisp.c (face_before_or_after_it_pos): Support bidi iteration.
         (next_element_from_c_string): Handle the case of the first string
         character that is not the first one in the visual order.
+        (get_visually_first_element): New function, refactored from common
+        parts of next_element_from_buffer, next_element_from_string, and
+        next_element_from_c_string.
 
 2011-06-16  Eli Zaretskii  <eliz@gnu.org>
 
diff --git a/src/xdisp.c b/src/xdisp.c
index 998076b30bb..ea55cdcc3d2 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -6658,6 +6658,107 @@ next_element_from_display_vector (struct it *it)
   return 1;
 }
 
+/* Get the first element of string/buffer in the visual order, after
+   being reseated to a new position in a string or a buffer.  */
+static void
+get_visually_first_element (struct it *it)
+{
+  int string_p = STRINGP (it->string) || it->s;
+  EMACS_INT eob = (string_p ? it->string_nchars : ZV);
+  EMACS_INT bob = (string_p ? 0 : BEGV);
+
+  if (STRINGP (it->string))
+    {
+      it->bidi_it.charpos = IT_STRING_CHARPOS (*it);
+      it->bidi_it.bytepos = IT_STRING_BYTEPOS (*it);
+    }
+  else
+    {
+      it->bidi_it.charpos = IT_CHARPOS (*it);
+      it->bidi_it.bytepos = IT_BYTEPOS (*it);
+    }
+
+  if (it->bidi_it.charpos == eob)
+    {
+      /* Nothing to do, but reset the FIRST_ELT flag, like
+         bidi_paragraph_init does, because we are not going to
+         call it.  */
+      it->bidi_it.first_elt = 0;
+    }
+  else if (it->bidi_it.charpos == bob
+           || (!string_p
+               /* FIXME: Should support all Unicode line separators.  */
+               && (FETCH_CHAR (it->bidi_it.bytepos - 1) == '\n'
+                   || FETCH_CHAR (it->bidi_it.bytepos) == '\n')))
+    {
+      /* If we are at the beginning of a line/string, we can produce
+         the next element right away.  */
+      bidi_paragraph_init (it->paragraph_embedding, &it->bidi_it, 1);
+      bidi_move_to_visually_next (&it->bidi_it);
+    }
+  else
+    {
+      EMACS_INT orig_bytepos = it->bidi_it.bytepos;
+
+      /* We need to prime the bidi iterator starting at the line's or
+         string's beginning, before we will be able to produce the
+         next element.  */
+      if (string_p)
+        it->bidi_it.charpos = it->bidi_it.bytepos = 0;
+      else
+        {
+          it->bidi_it.charpos = find_next_newline_no_quit (IT_CHARPOS (*it),
+                                                           -1);
+          it->bidi_it.bytepos = CHAR_TO_BYTE (it->bidi_it.charpos);
+        }
+      bidi_paragraph_init (it->paragraph_embedding, &it->bidi_it, 1);
+      do
+        {
+          /* Now return to buffer/string position where we were asked
+             to get the next display element, and produce that.  */
+          bidi_move_to_visually_next (&it->bidi_it);
+        }
+      while (it->bidi_it.bytepos != orig_bytepos
+             && it->bidi_it.charpos < eob);
+    }
+
+  /*  Adjust IT's position information to where we ended up.  */
+  if (STRINGP (it->string))
+    {
+      IT_STRING_CHARPOS (*it) = it->bidi_it.charpos;
+      IT_STRING_BYTEPOS (*it) = it->bidi_it.bytepos;
+    }
+  else
+    {
+      IT_CHARPOS (*it) = it->bidi_it.charpos;
+      IT_BYTEPOS (*it) = it->bidi_it.bytepos;
+    }
+
+  if (STRINGP (it->string) || !it->s)
+    {
+      EMACS_INT stop, charpos, bytepos;
+
+      if (STRINGP (it->string))
+        {
+          xassert (!it->s);
+          stop = SCHARS (it->string);
+          if (stop > it->end_charpos)
+            stop = it->end_charpos;
+          charpos = IT_STRING_CHARPOS (*it);
+          bytepos = IT_STRING_BYTEPOS (*it);
+        }
+      else
+        {
+          stop = it->end_charpos;
+          charpos = IT_CHARPOS (*it);
+          bytepos = IT_BYTEPOS (*it);
+        }
+      if (it->bidi_it.scan_dir < 0)
+        stop = -1;
+      composition_compute_stop_pos (&it->cmp_it, charpos, bytepos, stop,
+                                    it->string);
+    }
+}
 
 /* Load IT with the next display element from Lisp string IT->string.
    IT->current.string_pos is the current position within the string.
@@ -6680,56 +6781,8 @@ next_element_from_string (struct it *it)
      direction is not known.  */
   if (it->bidi_p && it->bidi_it.first_elt)
     {
-      it->bidi_it.charpos = CHARPOS (position);
-      it->bidi_it.bytepos = BYTEPOS (position);
-      if (it->bidi_it.charpos >= it->string_nchars)
-        {
-          /* Nothing to do, but reset the FIRST_ELT flag, like
-             bidi_paragraph_init does, because we are not going to
-             call it.  */
-          it->bidi_it.first_elt = 0;
-        }
-      else if (it->bidi_it.charpos <= 0)
-        {
-          /* If we are at the beginning of the string, we can produce
-             the next element right away.  */
-          bidi_paragraph_init (it->paragraph_embedding, &it->bidi_it, 1);
-          bidi_move_to_visually_next (&it->bidi_it);
-        }
-      else
-        {
-          EMACS_INT orig_bytepos = BYTEPOS (position);
-
-          /* We need to prime the bidi iterator starting at the string
-             beginning, before we will be able to produce the next
-             element.  */
-          it->bidi_it.charpos = it->bidi_it.bytepos = 0;
-          bidi_paragraph_init (it->paragraph_embedding, &it->bidi_it, 1);
-          do
-            {
-              /* Now return to buffer position where we were asked to
-                 get the next display element, and produce that.  */
-              bidi_move_to_visually_next (&it->bidi_it);
-            }
-          while (it->bidi_it.bytepos != orig_bytepos
-                 && it->bidi_it.charpos < it->string_nchars);
-        }
-
-      /*  Adjust IT's position information to where we ended up.  */
-      IT_STRING_CHARPOS (*it) = it->bidi_it.charpos;
-      IT_STRING_BYTEPOS (*it) = it->bidi_it.bytepos;
+      get_visually_first_element (it);
       SET_TEXT_POS (position, IT_STRING_CHARPOS (*it), IT_STRING_BYTEPOS (*it));
-      {
-        EMACS_INT stop = SCHARS (it->string);
-
-        if (it->bidi_it.scan_dir < 0)
-          stop = -1;
-        else if (stop > it->end_charpos)
-          stop = it->end_charpos;
-        composition_compute_stop_pos (&it->cmp_it, IT_STRING_CHARPOS (*it),
-                                      IT_STRING_BYTEPOS (*it), stop,
-                                      it->string);
-      }
     }
 
   /* Time to check for invisible text?  */
@@ -6894,46 +6947,7 @@ next_element_from_c_string (struct it *it)
      we were reseated to a new string, whose paragraph direction is
      not known.  */
   if (it->bidi_p && it->bidi_it.first_elt)
-    {
-      it->bidi_it.charpos = IT_CHARPOS (*it);
-      it->bidi_it.bytepos = IT_BYTEPOS (*it);
-      if (it->bidi_it.charpos >= it->string_nchars)
-        {
-          /* Nothing to do, but reset the FIRST_ELT flag, like
-             bidi_paragraph_init does, because we are not going to
-             call it.  */
-          it->bidi_it.first_elt = 0;
-        }
-      else if (it->bidi_it.charpos <= 0)
-        {
-          /* If we are at the beginning of the string, we can produce
-             the next element right away.  */
-          bidi_paragraph_init (it->paragraph_embedding, &it->bidi_it, 1);
-          bidi_move_to_visually_next (&it->bidi_it);
-        }
-      else
-        {
-          EMACS_INT orig_bytepos = IT_BYTEPOS (*it);
-
-          /* We need to prime the bidi iterator starting at the string
-             beginning, before we will be able to produce the next
-             element.  */
-          it->bidi_it.charpos = it->bidi_it.bytepos = 0;
-          bidi_paragraph_init (it->paragraph_embedding, &it->bidi_it, 1);
-          do
-            {
-              /* Now return to buffer position where we were asked to
-                 get the next display element, and produce that.  */
-              bidi_move_to_visually_next (&it->bidi_it);
-            }
-          while (it->bidi_it.bytepos != orig_bytepos
-                 && it->bidi_it.charpos < it->string_nchars);
-        }
-
-      /*  Adjust IT's position information to where we ended up.  */
-      IT_CHARPOS (*it) = it->bidi_it.charpos;
-      IT_BYTEPOS (*it) = it->bidi_it.bytepos;
-    }
+    get_visually_first_element (it);
 
   /* IT's position can be greater than IT->string_nchars in case a
      field width or precision has been specified when the iterator was
@@ -7069,6 +7083,7 @@ next_element_from_buffer (struct it *it)
   int success_p = 1;
 
   xassert (IT_CHARPOS (*it) >= BEGV);
+  xassert (NILP (it->string) && !it->s);
   xassert (!it->bidi_p
            || (it->bidi_it.string.lstring == Qnil
                && it->bidi_it.string.s == NULL));
@@ -7079,59 +7094,8 @@ next_element_from_buffer (struct it *it)
      a different paragraph.  */
   if (it->bidi_p && it->bidi_it.first_elt)
     {
-      it->bidi_it.charpos = IT_CHARPOS (*it);
-      it->bidi_it.bytepos = IT_BYTEPOS (*it);
-      if (it->bidi_it.bytepos == ZV_BYTE)
-        {
-          /* Nothing to do, but reset the FIRST_ELT flag, like
-             bidi_paragraph_init does, because we are not going to
-             call it.  */
-          it->bidi_it.first_elt = 0;
-        }
-      else if (it->bidi_it.bytepos == BEGV_BYTE
-          /* FIXME: Should support all Unicode line separators.  */
-          || FETCH_CHAR (it->bidi_it.bytepos - 1) == '\n'
-          || FETCH_CHAR (it->bidi_it.bytepos) == '\n')
-        {
-          /* If we are at the beginning of a line, we can produce the
-             next element right away.  */
-          bidi_paragraph_init (it->paragraph_embedding, &it->bidi_it, 1);
-          bidi_move_to_visually_next (&it->bidi_it);
-        }
-      else
-        {
-          EMACS_INT orig_bytepos = IT_BYTEPOS (*it);
-
-          /* We need to prime the bidi iterator starting at the line's
-             beginning, before we will be able to produce the next
-             element.  */
-          IT_CHARPOS (*it) = find_next_newline_no_quit (IT_CHARPOS (*it), -1);
-          IT_BYTEPOS (*it) = CHAR_TO_BYTE (IT_CHARPOS (*it));
-          it->bidi_it.charpos = IT_CHARPOS (*it);
-          it->bidi_it.bytepos = IT_BYTEPOS (*it);
-          bidi_paragraph_init (it->paragraph_embedding, &it->bidi_it, 1);
-          do
-            {
-              /* Now return to buffer position where we were asked to
-                 get the next display element, and produce that.  */
-              bidi_move_to_visually_next (&it->bidi_it);
-            }
-          while (it->bidi_it.bytepos != orig_bytepos
-                 && it->bidi_it.bytepos < ZV_BYTE);
-        }
-
-      it->bidi_it.first_elt = 0; /* paranoia: bidi.c does this */
-      /*  Adjust IT's position information to where we ended up.  */
-      IT_CHARPOS (*it) = it->bidi_it.charpos;
-      IT_BYTEPOS (*it) = it->bidi_it.bytepos;
+      get_visually_first_element (it);
       SET_TEXT_POS (it->position, IT_CHARPOS (*it), IT_BYTEPOS (*it));
-      {
-        EMACS_INT stop = it->end_charpos;
-        if (it->bidi_it.scan_dir < 0)
-          stop = -1;
-        composition_compute_stop_pos (&it->cmp_it, IT_CHARPOS (*it),
-                                      IT_BYTEPOS (*it), stop, Qnil);
-      }
     }
 
   if (IT_CHARPOS (*it) >= it->stop_charpos)