Add termpastefilter option

Change to specify a character to be filtered as an option when pasting on
the terminal.

runtime/doc/options.txt

@@ -6289,6 +6289,29 @@ A jump table for the options with a short description can be found at |Q_op|.
 	attributes instead of "cterm" attributes. |highlight-guifg|
 	Requires an ISO-8613-3 compatible terminal.
 
+						*'termpastefilter'* *'tpf'*
+'termpastefilter' 'tpf'	string	(default: "")
+			global
+	A comma separated list of options for specifying control characters
+	to be removed from the text pasted into the terminal window. The
+	supported values are:
+
+	   BS	    Backspace
+
+	   HT	    TAB
+
+	   FF	    Form feed
+
+	   ESC	    Escape
+
+	   DEL	    DEL
+
+	   C0	    Other control characters, excluding Line feed and
+		    Carriage return < ' '
+
+	   C1	    Control characters 0x80...0x9F
+
+
 						*'terse'* *'noterse'*
 'terse'			boolean	(default off)
 			global

src/nvim/option.c

@@ -1942,6 +1942,7 @@ static void didset_options(void)
   (void)opt_strings_flags(p_dy, p_dy_values, &dy_flags, true);
   (void)opt_strings_flags(p_rdb, p_rdb_values, &rdb_flags, true);
   (void)opt_strings_flags(p_tc, p_tc_values, &tc_flags, false);
+  (void)opt_strings_flags(p_tpf, p_tpf_values, &tpf_flags, true);
   (void)opt_strings_flags(p_ve, p_ve_values, &ve_flags, true);
   (void)opt_strings_flags(p_wop, p_wop_values, &wop_flags, true);
   (void)opt_strings_flags(p_jop, p_jop_values, &jop_flags, true);
@@ -3077,6 +3078,10 @@ ambw_end:
     if (!parse_winhl_opt(curwin)) {
       errmsg = e_invarg;
     }
+  } else if (varp == &p_tpf) {
+    if (opt_strings_flags(p_tpf, p_tpf_values, &tpf_flags, true) != OK) {
+      errmsg = e_invarg;
+    }
   } else {
     // Options that are a list of flags.
     p = NULL;

src/nvim/option_defs.h

@@ -621,6 +621,19 @@ EXTERN int p_sta;               // 'smarttab'
 EXTERN int p_sb;                // 'splitbelow'
 EXTERN long p_tpm;              // 'tabpagemax'
 EXTERN char_u   *p_tal;         // 'tabline'
+EXTERN char_u   *p_tpf;         // 'termpastefilter'
+EXTERN unsigned int tpf_flags;  ///< flags from 'termpastefilter'
+#ifdef IN_OPTION_C
+static char *(p_tpf_values[]) =
+  { "BS", "HT", "FF", "ESC", "DEL", "C0", "C1", NULL };
+#endif
+# define TPF_BS                 0x001
+# define TPF_HT                 0x002
+# define TPF_FF                 0x004
+# define TPF_ESC                0x008
+# define TPF_DEL                0x010
+# define TPF_C0                 0x020
+# define TPF_C1                 0x040
 EXTERN char_u   *p_sps;         // 'spellsuggest'
 EXTERN int p_spr;               // 'splitright'
 EXTERN int p_sol;               // 'startofline'

src/nvim/options.lua

@@ -2820,6 +2820,14 @@ return {
       varname='p_tgc',
       defaults={if_true={vi=false}}
     },
+    {
+      full_name='termpastefilter', abbreviation='tpf',
+      type='string', list='onecomma', scope={'global'},
+      deny_duplicates=true,
+      vim=true,
+      varname='p_tpf',
+      defaults={if_true={vi="", vim=""}}
+    },
     {
       full_name='terse',
       short_desc=N_("hides notification of search wrap"),

src/nvim/terminal.c

@@ -535,6 +535,38 @@ void terminal_send(Terminal *term, char *data, size_t size)
   term->opts.write_cb(data, size, term->opts.data);
 }
 
+static bool is_filter_char(int c)
+{
+  unsigned int flag = 0;
+  switch (c) {
+    case 0x08:
+      flag = TPF_BS;
+      break;
+    case 0x09:
+      flag = TPF_HT;
+      break;
+    case 0x0A:
+    case 0x0D:
+      break;
+    case 0x0C:
+      flag = TPF_FF;
+      break;
+    case 0x1b:
+      flag = TPF_ESC;
+      break;
+    case 0x7F:
+      flag = TPF_DEL;
+      break;
+    default:
+      if (c < ' ') {
+        flag = TPF_C0;
+      } else if (c >= 0x80 && c <= 0x9F) {
+        flag = TPF_C1;
+      }
+  }
+  return !!(tpf_flags & flag);
+}
+
 void terminal_paste(long count, char_u **y_array, size_t y_size)
 {
   vterm_keyboard_start_paste(curbuf->terminal->vt);
@@ -553,16 +585,18 @@ void terminal_paste(long count, char_u **y_array, size_t y_size)
         buff = xrealloc(buff, len);
         buff_len = len;
       }
-      char_u *p = buff;
-      char_u *q = y_array[j];
-      while (*q != '\0') {
-        if ((*q > '\x07' && *q < '\x0e' && *q != '\x0b' && *q != '\x0c')
-            || *q > '\x1f') {
-          *(p++) = *q;
+      char_u *dst = buff;
+      char_u *src = y_array[j];
+      while (*src != '\0') {
+        len = (size_t)utf_ptr2len(src);
+        int c = utf_ptr2char(src);
+        if (!is_filter_char(c)) {
+          memcpy(dst, src, len);
+          dst += len;
         }
-        q++;
+        src += len;
       }
-      terminal_send(curbuf->terminal, (char *)buff, (size_t)(p - buff));
+      terminal_send(curbuf->terminal, (char *)buff, (size_t)(dst - buff));
     }
   }
   xfree(buff);