composite.c (composition_reseat_it): Handle the case that a grapheme cluster is not covered by a single font (Bug#12352).

2 files changed, 25 insertions, 31 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index be734134adf..8a05f19985f 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2012-09-22  Kenichi Handa  <handa@gnu.org>
+
+        * composite.c (composition_reseat_it): Handle the case that a
+        grapheme cluster is not covered by a single font (Bug#12352).
+
 2012-09-17  Kenichi Handa  <handa@gnu.org>
 
         * font.c (Ffont_shape_gstring): Fix previous change; GLYPHs may
diff --git a/src/composite.c b/src/composite.c
index ae46df0a573..6c603fab3fc 100644
--- a/src/composite.c
+++ b/src/composite.c
@@ -1219,9 +1219,6 @@ composition_reseat_it (struct composition_it *cmp_it, ptrdiff_t charpos,
                        ptrdiff_t bytepos, ptrdiff_t endpos, struct window *w,
                        struct face *face, Lisp_Object string)
 {
-  if (endpos < 0)
-    endpos = NILP (string) ? BEGV : 0;
-
   if (cmp_it->ch == -2)
     {
       composition_compute_stop_pos (cmp_it, charpos, bytepos, endpos, string);
@@ -1230,6 +1227,9 @@ composition_reseat_it (struct composition_it *cmp_it, ptrdiff_t charpos,
         return 0;
     }
 
+  if (endpos < 0)
+    endpos = NILP (string) ? BEGV : 0;
+
   if (cmp_it->ch < 0)
     {
       /* We are looking at a static composition.  */
@@ -1277,36 +1277,23 @@ composition_reseat_it (struct composition_it *cmp_it, ptrdiff_t charpos,
         {
           ptrdiff_t cpos = charpos, bpos = bytepos;
 
-          while (1)
+          cmp_it->reversed_p = 1;
+          elt = XCAR (val);
+          if (cmp_it->lookback > 0)
             {
-              elt = XCAR (val);
-              if (cmp_it->lookback > 0)
-                {
-                  cpos = charpos - cmp_it->lookback;
-                  if (STRINGP (string))
-                    bpos = string_char_to_byte (string, cpos);
-                  else
-                    bpos = CHAR_TO_BYTE (cpos);
-                }
-              lgstring = autocmp_chars (elt, cpos, bpos, charpos + 1, w, face,
-                                        string);
-              if (composition_gstring_p (lgstring)
-                  && cpos + LGSTRING_CHAR_LEN (lgstring) - 1 == charpos)
-                break;
-              /* Composition failed or didn't cover the current
-                 character.  */
-              if (cmp_it->lookback == 0)
-                goto no_composition;
-              lgstring = Qnil;
-              /* Try to find a shorter composition that starts after CPOS.  */
-              composition_compute_stop_pos (cmp_it, charpos, bytepos, cpos,
-                                            string);
-              if (cmp_it->ch == -2 || cmp_it->stop_pos < charpos)
-                goto no_composition;
-              val = CHAR_TABLE_REF (Vcomposition_function_table, cmp_it->ch);
-              for (i = 0; i < cmp_it->rule_idx; i++, val = XCDR (val));
+              cpos = charpos - cmp_it->lookback;
+              if (STRINGP (string))
+                bpos = string_char_to_byte (string, cpos);
+              else
+                bpos = CHAR_TO_BYTE (cpos);
             }
-          cmp_it->reversed_p = 1;
+          lgstring = autocmp_chars (elt, cpos, bpos, charpos + 1, w, face,
+                                    string);
+          if (! composition_gstring_p (lgstring)
+              || cpos + LGSTRING_CHAR_LEN (lgstring) - 1 != charpos)
+            /* Composition failed or didn't cover the current
+               character.  */
+            goto no_composition;
         }
       if (NILP (lgstring))
         goto no_composition;
@@ -1341,6 +1328,8 @@ composition_reseat_it (struct composition_it *cmp_it, ptrdiff_t charpos,
       /* BYTEPOS is calculated in composition_compute_stop_pos */
       bytepos = -1;
     }
+  if (cmp_it->reversed_p)
+    endpos = -1;
   composition_compute_stop_pos (cmp_it, charpos, bytepos, endpos, string);
   return 0;
 }