loadfile: clip long track titles

When a track title is taken from its filename and is very long, clip it
to not make track information too verbose.

term_disp_width() is convenient even for ASS output because it avoids
cutting in the middle of UTF-8 characters.

Fixes #10975 along with #17021.

Author: guidocella

player/loadfile.c

@@ -25,6 +25,7 @@
 
 #include "mpv_talloc.h"
 
+#include "misc/codepoint_width.h"
 #include "misc/thread_pool.h"
 #include "misc/thread_tools.h"
 #include "osdep/io.h"
@@ -909,8 +910,16 @@ int mp_add_external_file(struct MPContext *mpctx, char *filename,
             bstr title = bstr0(mp_basename(disp_filename));
             bstr_eatstart(&title, parent);
             bstr_eatstart(&title, bstr0("."));
-            if (title.len)
+
+            const unsigned char *cut_pos = NULL;
+            if (mp_is_url(bstr0(disp_filename)))
+                term_disp_width(title, 90, &cut_pos);
+            if (cut_pos) {
+                title.len = cut_pos - title.start;
+                t->title = talloc_asprintf(t, "%.*s\u2026", BSTR_P(title));
+            } else if (title.len) {
                 t->title = bstrdup0(t, title);
+            }
         }
         t->external_filename = mp_normalize_user_path(t, mpctx->global, filename);
         t->no_default = sh->type != filter;