refactor(options): use schar_T representation for fillchars and listchars

A bit big, but practically it was a lot simpler to change over all
fillchars and all listchars at once, to not need to maintain two
parallel implementations.

This is mostly an internal refactor, but it also removes an arbitrary
limitation: that 'fillchars' and 'listchars' values can only be
single-codepoint characters. Now any character which fits into a single
screen cell can be used.

1 files changed, 8 insertions, 14 deletions

diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index 2bb3f0fac7..f683789945 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -2132,7 +2132,7 @@ Dictionary nvim_eval_statusline(String str, Dict(eval_statusline) *opts, Error *
   Dictionary result = ARRAY_DICT_INIT;
 
   int maxwidth;
-  int fillchar = 0;
+  schar_T fillchar = 0;
   int statuscol_lnum = 0;
   Window window = 0;
 
@@ -2148,11 +2148,13 @@ Dictionary nvim_eval_statusline(String str, Dict(eval_statusline) *opts, Error *
   }
   if (HAS_KEY(opts, eval_statusline, fillchar)) {
     VALIDATE_EXP((*opts->fillchar.data != 0
-                  && ((size_t)utf_ptr2len(opts->fillchar.data) == opts->fillchar.size)),
+                  && ((size_t)utfc_ptr2len(opts->fillchar.data) == opts->fillchar.size)),
                  "fillchar", "single character", NULL, {
       return result;
     });
-    fillchar = utf_ptr2char(opts->fillchar.data);
+    int c;
+    fillchar = utfc_ptr2schar(opts->fillchar.data, &c);
+    // TODO(bfredl): actually check c is single width
   }
 
   int use_bools = (int)opts->use_winbar + (int)opts->use_tabline;
@@ -2181,7 +2183,7 @@ Dictionary nvim_eval_statusline(String str, Dict(eval_statusline) *opts, Error *
   SignTextAttrs sattrs[SIGN_SHOW_MAX] = { 0 };
 
   if (opts->use_tabline) {
-    fillchar = ' ';
+    fillchar = schar_from_ascii(' ');
   } else {
     if (fillchar == 0) {
       if (opts->use_winbar) {
@@ -2242,16 +2244,8 @@ Dictionary nvim_eval_statusline(String str, Dict(eval_statusline) *opts, Error *
   int p_crb_save = wp->w_p_crb;
   wp->w_p_crb = false;
 
-  int width = build_stl_str_hl(wp,
-                               buf,
-                               sizeof(buf),
-                               str.data,
-                               -1,
-                               0,
-                               fillchar,
-                               maxwidth,
-                               opts->highlights ? &hltab : NULL,
-                               NULL,
+  int width = build_stl_str_hl(wp, buf, sizeof(buf), str.data, -1, 0, fillchar, maxwidth,
+                               opts->highlights ? &hltab : NULL, NULL,
                                statuscol_lnum ? &statuscol : NULL);
 
   PUT(result, "width", INTEGER_OBJ(width));