Permit XLFD names to exceed 255 characters

* doc/lispref/display.texi (Low-Level Font)
<font-xlfd-name>: Document new argument `long-xlfds'.

* etc/NEWS: Mention removal of XLFD length restrictions.

* src/font.c (font_build_object): Dynamically allocate XLFD,
permitting them to surpass 255 characters in length.
(font_parse_xlfd_1): Cease rejecting XLFDs more than 255
characters in length.
(font_dynamic_unparse_xlfd): New function.  Like
font_unparse_xlfd, but allocate the XLFD dynamically.
(font_delete_unmatched): Dynamically allocate XLFD if necessary.
(Ffont_xlfd_name): New arg LONG_XLFDs.  If t, return a
dynamically allocated XLFD.  All callers changed.

* src/font.h: Update prototypes.

* src/fontset.c (Fnew_fontset): Dynamically allocate XLFD when
establishing fontset name.

1 files changed, 26 insertions, 13 deletions

diff --git a/src/fontset.c b/src/fontset.c
index 139dcb6eb89..347763cd77e 100644
--- a/src/fontset.c
+++ b/src/fontset.c
@@ -1546,7 +1546,7 @@ overwrites the previous settings.  */)
 
       font_parse_family_registry (XCAR (font_spec), XCDR (font_spec), spec);
       font_spec = spec;
-      fontname = Ffont_xlfd_name (font_spec, Qnil);
+      fontname = Ffont_xlfd_name (font_spec, Qnil, Qt);
     }
   else if (STRINGP (font_spec))
     {
@@ -1554,7 +1554,7 @@ overwrites the previous settings.  */)
       font_spec = CALLN (Ffont_spec, QCname, fontname);
     }
   else if (FONT_SPEC_P (font_spec))
-    fontname = Ffont_xlfd_name (font_spec, Qnil);
+    fontname = Ffont_xlfd_name (font_spec, Qnil, Qt);
   else if (! NILP (font_spec))
     Fsignal (Qfont, list2 (build_string ("Invalid font-spec"), font_spec));
 
@@ -1740,6 +1740,7 @@ FONT-SPEC is a vector, a cons, or a string.  See the documentation of
 {
   Lisp_Object fontset, tail;
   int id;
+  char *string;
 
   CHECK_STRING (name);
 
@@ -1749,8 +1750,6 @@ FONT-SPEC is a vector, a cons, or a string.  See the documentation of
     {
       Lisp_Object font_spec = Ffont_spec (0, NULL);
       Lisp_Object short_name;
-      char xlfd[256];
-      int len;
 
       if (font_parse_xlfd (SSDATA (name), SBYTES (name), font_spec) < 0)
 	error ("Fontset name must be in XLFD format");
@@ -1762,10 +1761,11 @@ FONT-SPEC is a vector, a cons, or a string.  See the documentation of
 				    Vfontset_alias_alist);
       ASET (font_spec, FONT_REGISTRY_INDEX, Qiso8859_1);
       fontset = make_fontset (Qnil, name, Qnil);
-      len = font_unparse_xlfd (font_spec, 0, xlfd, 256);
-      if (len < 0)
+      string = font_dynamic_unparse_xlfd (font_spec, 0);
+      if (!string)
 	error ("Invalid fontset name (perhaps too long): %s", SDATA (name));
-      set_fontset_ascii (fontset, make_unibyte_string (xlfd, len));
+      set_fontset_ascii (fontset, build_unibyte_string (string));
+      xfree (string);
     }
   else
     {
@@ -1816,7 +1816,7 @@ fontset_from_font (Lisp_Object font_object)
   Lisp_Object font_spec = copy_font_spec (font_object);
   Lisp_Object registry = AREF (font_spec, FONT_REGISTRY_INDEX);
   Lisp_Object fontset_spec, alias, name, fontset;
-  Lisp_Object val;
+  Lisp_Object val, xlfd;
 
   val = assoc_no_quit (font_spec, auto_fontset_alist);
   if (CONSP (val))
@@ -1832,14 +1832,27 @@ fontset_from_font (Lisp_Object font_object)
     }
   fontset_spec = copy_font_spec (font_spec);
   ASET (fontset_spec, FONT_REGISTRY_INDEX, alias);
-  name = Ffont_xlfd_name (fontset_spec, Qnil);
+  name = Ffont_xlfd_name (fontset_spec, Qnil, Qt);
   eassert (!NILP (name));
   fontset = make_fontset (Qnil, name, Qnil);
   Vfontset_alias_alist = Fcons (Fcons (name, SYMBOL_NAME (alias)),
 				Vfontset_alias_alist);
-  alias = Fdowncase (AREF (font_object, FONT_NAME_INDEX));
-  Vfontset_alias_alist = Fcons (Fcons (name, alias), Vfontset_alias_alist);
-  auto_fontset_alist = Fcons (Fcons (font_spec, fontset), auto_fontset_alist);
+
+  xlfd = AREF (font_object, FONT_NAME_INDEX);
+
+  /* XLFD can be nil if the font's registry or family name gives rise
+     to an XLFD name that cannot be represented within 255
+     characters.  (bug#65800) */
+
+  if (!NILP (xlfd))
+    {
+      alias = Fdowncase (xlfd);
+      Vfontset_alias_alist
+	= Fcons (Fcons (name, alias), Vfontset_alias_alist);
+      auto_fontset_alist
+	= Fcons (Fcons (font_spec, fontset), auto_fontset_alist);
+    }
+
   font_spec = Ffont_spec (0, NULL);
   ASET (font_spec, FONT_REGISTRY_INDEX, registry);
   {
@@ -2006,7 +2019,7 @@ format is the same as above.  */)
 	      for (; CONSP (alist); alist = XCDR (alist))
 		{
 		  elt = XCAR (alist);
-		  XSETCAR (elt, Ffont_xlfd_name (XCAR (elt), Qnil));
+		  XSETCAR (elt, Ffont_xlfd_name (XCAR (elt), Qnil, Qt));
 		}
 	    }
 	  c = to + 1;