refactor: adopt termkey and eliminate duplicate code

Termkey is abandoned and it's now our code, so there's no reason not to
treat it as such. An alternative approach could be to have a proper repo
that we maintain such as with unibilium, although with this approach we
can make a few assumptions that will allow us to remove more code.

Also eliminate duplicate code from both termkey and libvterm.

4 files changed, 5 insertions, 44 deletions

diff --git a/src/vterm/keyboard.c b/src/vterm/keyboard.c
index d31c8be12d..7e062c8c02 100644
--- a/src/vterm/keyboard.c
+++ b/src/vterm/keyboard.c
@@ -1,8 +1,7 @@
 #include "vterm_internal.h"
-
 #include <stdio.h>
 
-#include "utf8.h"
+#include "nvim/tui/termkey/termkey.h"
 
 void vterm_keyboard_unichar(VTerm *vt, uint32_t c, VTermModifier mod)
 {
diff --git a/src/vterm/mouse.c b/src/vterm/mouse.c
index f74abc3d9d..a9d3fe4ca9 100644
--- a/src/vterm/mouse.c
+++ b/src/vterm/mouse.c
@@ -1,6 +1,6 @@
 #include "vterm_internal.h"
 
-#include "utf8.h"
+#include "nvim/tui/termkey/termkey.h"
 
 static void output_mouse(VTermState *state, int code, int pressed, int modifiers, int col, int row)
 {
diff --git a/src/vterm/screen.c b/src/vterm/screen.c
index bd3cbd6bd0..e63db483f9 100644
--- a/src/vterm/screen.c
+++ b/src/vterm/screen.c
@@ -2,9 +2,10 @@
 
 #include <stdio.h>
 #include <string.h>
+#include "nvim/mbyte.h"
+#include "nvim/tui/termkey/termkey.h"
 
 #include "rect.h"
-#include "utf8.h"
 
 #define UNICODE_SPACE 0x20
 #define UNICODE_LINEFEED 0x0a
@@ -922,7 +923,7 @@ static size_t _get_chars(const VTermScreen *screen, const int utf8, void *buffer
 
 #define PUT(c)                                             \
   if(utf8) {                                               \
-    size_t thislen = utf8_seqlen(c);                       \
+    size_t thislen = utf_char2len(c);                      \
     if(buffer && outpos + thislen <= len)                  \
       outpos += fill_utf8((c), (char *)buffer + outpos);   \
     else                                                   \
diff --git a/src/vterm/utf8.h b/src/vterm/utf8.h
deleted file mode 100644
index 9a336d357f..0000000000
--- a/src/vterm/utf8.h
+++ /dev/null
@@ -1,39 +0,0 @@
-/* The following functions copied and adapted from libtermkey
- *
- * http://www.leonerd.org.uk/code/libtermkey/
- */
-static inline unsigned int utf8_seqlen(long codepoint)
-{
-  if(codepoint < 0x0000080) return 1;
-  if(codepoint < 0x0000800) return 2;
-  if(codepoint < 0x0010000) return 3;
-  if(codepoint < 0x0200000) return 4;
-  if(codepoint < 0x4000000) return 5;
-  return 6;
-}
-
-/* Does NOT NUL-terminate the buffer */
-static int fill_utf8(long codepoint, char *str)
-{
-  int nbytes = utf8_seqlen(codepoint);
-
-  // This is easier done backwards
-  int b = nbytes;
-  while(b > 1) {
-    b--;
-    str[b] = 0x80 | (codepoint & 0x3f);
-    codepoint >>= 6;
-  }
-
-  switch(nbytes) {
-    case 1: str[0] =        (codepoint & 0x7f); break;
-    case 2: str[0] = 0xc0 | (codepoint & 0x1f); break;
-    case 3: str[0] = 0xe0 | (codepoint & 0x0f); break;
-    case 4: str[0] = 0xf0 | (codepoint & 0x07); break;
-    case 5: str[0] = 0xf8 | (codepoint & 0x03); break;
-    case 6: str[0] = 0xfc | (codepoint & 0x01); break;
-  }
-
-  return nbytes;
-}
-/* end copy */