Merge pull request #8546 from bfredl/eob

Add fillchar for EndOfBuffer and check for invalid UTF-8

6 files changed, 83 insertions, 8 deletions

diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index 3bc248c795..f924003e1f 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -2393,6 +2393,7 @@ A jump table for the options with a short description can be found at |Q_op|.
 	  fold:c	'·' or '-'	filling 'foldtext'
 	  diff:c	'-'		deleted lines of the 'diff' option
 	  msgsep:c	' '		message separator 'display'
+	  eob:c		'~'		empty lines at the end of a buffer
 
 	Any one that is omitted will fall back to the default.  For "stl" and
 	"stlnc" the space will be used when there is highlighting, '^' or '='
@@ -2415,6 +2416,7 @@ A jump table for the options with a short description can be found at |Q_op|.
 	  vert:c	VertSplit		|hl-VertSplit|
 	  fold:c	Folded			|hl-Folded|
 	  diff:c	DiffDelete		|hl-DiffDelete|
+	  eob:c		EndOfBuffer		|hl-EndOfBuffer|
 
 		*'fixendofline'* *'fixeol'* *'nofixendofline'* *'nofixeol'*
 'fixendofline' 'fixeol'	boolean	(default on)
diff --git a/runtime/doc/vim_diff.txt b/runtime/doc/vim_diff.txt
index 9dd03079fe..5394414947 100644
--- a/runtime/doc/vim_diff.txt
+++ b/runtime/doc/vim_diff.txt
@@ -180,7 +180,8 @@ Options:
   'cpoptions' flags: |cpo-_|
   'display' flag `msgsep` to minimize scrolling when showing messages
   'guicursor' works in the terminal
-  'fillchars' flag `msgsep` (see 'display' above)
+  'fillchars' flags: `msgsep` (see 'display' above)
+	      and `eob` for |EndOfBuffer| marker
   'inccommand' shows interactive results for |:substitute|-like commands
   'scrollback'
   'statusline' supports unlimited alignment sections
diff --git a/src/nvim/globals.h b/src/nvim/globals.h
index 20e5353b51..f5ebaa9753 100644
--- a/src/nvim/globals.h
+++ b/src/nvim/globals.h
@@ -908,6 +908,7 @@ EXTERN int fill_vert INIT(= 9474);  // │
 EXTERN int fill_fold INIT(= 183);   // ·
 EXTERN int fill_diff INIT(= '-');
 EXTERN int fill_msgsep INIT(= ' ');
+EXTERN int fill_eob INIT(= '~');
 
 /* Whether 'keymodel' contains "stopsel" and "startsel". */
 EXTERN int km_stopsel INIT(= FALSE);
diff --git a/src/nvim/option.c b/src/nvim/option.c
index a7ee0ef28b..e65798e57a 100644
--- a/src/nvim/option.c
+++ b/src/nvim/option.c
@@ -3386,6 +3386,7 @@ static char_u *set_chars_option(char_u **varp)
     { &fill_fold,    "fold" , 183  },  // ·
     { &fill_diff,    "diff" , '-'  },
     { &fill_msgsep,  "msgsep", ' ' },
+    { &fill_eob,     "eob",   '~' },
   };
   static struct charstab lcstab[] = {
     { &lcs_eol,      "eol",      NUL },
@@ -3437,16 +3438,20 @@ static char_u *set_chars_option(char_u **varp)
             && p[len] == ':'
             && p[len + 1] != NUL) {
           s = p + len + 1;
-          c1 = mb_ptr2char_adv((const char_u **)&s);
-          if (mb_char2cells(c1) > 1) {
+
+          // TODO(bfredl): use schar_T representation and utfc_ptr2len
+          int c1len = utf_ptr2len(s);
+          c1 = mb_cptr2char_adv((const char_u **)&s);
+          if (mb_char2cells(c1) > 1 || (c1len == 1 && c1 > 127)) {
             continue;
           }
           if (tab[i].cp == &lcs_tab2) {
             if (*s == NUL) {
               continue;
             }
-            c2 = mb_ptr2char_adv((const char_u **)&s);
-            if (mb_char2cells(c2) > 1) {
+            int c2len = utf_ptr2len(s);
+            c2 = mb_cptr2char_adv((const char_u **)&s);
+            if (mb_char2cells(c2) > 1 || (c2len == 1 && c2 > 127)) {
               continue;
             }
           }
diff --git a/src/nvim/screen.c b/src/nvim/screen.c
index cf9a72715b..80f7a32c07 100644
--- a/src/nvim/screen.c
+++ b/src/nvim/screen.c
@@ -1532,9 +1532,9 @@ static void win_update(win_T *wp)
     } else if (dollar_vcol == -1)
       wp->w_botline = lnum;
 
-    /* make sure the rest of the screen is blank */
-    /* put '~'s on rows that aren't part of the file. */
-    win_draw_end(wp, '~', ' ', row, wp->w_height, HLF_EOB);
+    // make sure the rest of the screen is blank
+    // write the 'fill_eob' character to rows that aren't part of the file.
+    win_draw_end(wp, fill_eob, ' ', row, wp->w_height, HLF_EOB);
   }
 
   /* Reset the type of redrawing required, the window has been updated. */
diff --git a/test/functional/options/fillchars_spec.lua b/test/functional/options/fillchars_spec.lua
new file mode 100644
index 0000000000..ab61935d4c
--- /dev/null
+++ b/test/functional/options/fillchars_spec.lua
@@ -0,0 +1,66 @@
+local helpers = require('test.functional.helpers')(after_each)
+local Screen = require('test.functional.ui.screen')
+local clear, command = helpers.clear, helpers.command
+local eval = helpers.eval
+local eq = helpers.eq
+local exc_exec = helpers.exc_exec
+
+describe("'fillchars'", function()
+  local screen
+
+  before_each(function()
+    clear()
+    screen = Screen.new(25, 5)
+    screen:attach()
+  end)
+
+  after_each(function()
+    screen:detach()
+  end)
+
+  local function shouldfail(val,errval)
+    errval = errval or val
+    eq('Vim(set):E474: Invalid argument: fillchars='..errval,
+       exc_exec('set fillchars='..val))
+  end
+
+  describe('"eob" flag', function()
+    it("uses '~' by default", function()
+      eq('', eval('&fillchars'))
+      screen:expect([[
+        ^                         |
+        ~                        |
+        ~                        |
+        ~                        |
+                                 |
+      ]])
+    end)
+    it('supports whitespace', function()
+      command('set fillchars=eob:\\ ')
+      screen:expect([[
+        ^                         |
+                                 |
+                                 |
+                                 |
+                                 |
+      ]])
+    end)
+    it('supports multibyte char', function()
+      command('set fillchars=eob:ñ')
+      screen:expect([[
+        ^                         |
+        ñ                        |
+        ñ                        |
+        ñ                        |
+                                 |
+      ]])
+    end)
+    it('handles invalid values', function()
+      shouldfail('eob:') -- empty string
+      shouldfail('eob:馬') -- doublewidth char
+      shouldfail('eob:å̲') -- composing chars
+      shouldfail('eob:xy') -- two ascii chars
+      shouldfail('eob:\255', 'eob:<ff>') -- invalid UTF-8
+    end)
+  end)
+end)