refactor(plines): use a struct for chartabsize state

This is a refactor extracted from vim-patch 9.0.0067: cannot show virtual text

The logic for inline virtual text is going to be different in nvim than
text property based text in vim, but this refactor is still useful,
as calculation of displayed linesize is going to be stateful in a
similar way.

1 files changed, 19 insertions, 9 deletions

diff --git a/src/nvim/drawline.c b/src/nvim/drawline.c
index 9132d6666e..4b5f6c6c06 100644
--- a/src/nvim/drawline.c
+++ b/src/nvim/drawline.c
@@ -940,12 +940,19 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange,
   }
   if (v > 0 && !number_only) {
     char_u *prev_ptr = ptr;
-    while (vcol < v && *ptr != NUL) {
-      c = win_lbr_chartabsize(wp, line, ptr, (colnr_T)vcol, NULL);
-      vcol += c;
-      prev_ptr = ptr;
-      MB_PTR_ADV(ptr);
+    chartabsize_T cts;
+    int charsize;
+
+    init_chartabsize_arg(&cts, wp, lnum, (colnr_T)vcol, line, ptr);
+    while (cts.cts_vcol < v && *cts.cts_ptr != NUL) {
+      charsize = win_lbr_chartabsize(&cts, NULL);
+      cts.cts_vcol += charsize;
+      prev_ptr = (char_u *)cts.cts_ptr;
+      MB_PTR_ADV(cts.cts_ptr);
     }
+    vcol = cts.cts_vcol;
+    ptr = (char_u *)cts.cts_ptr;
+    clear_chartabsize_arg(&cts);
 
     // When:
     // - 'cuc' is set, or
@@ -963,11 +970,11 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange,
     // Handle a character that's not completely on the screen: Put ptr at
     // that character but skip the first few screen characters.
     if (vcol > v) {
-      vcol -= c;
+      vcol -= charsize;
       ptr = prev_ptr;
       // If the character fits on the screen, don't need to skip it.
       // Except for a TAB.
-      if (utf_ptr2cells((char *)ptr) >= c || *ptr == TAB) {
+      if (utf_ptr2cells((char *)ptr) >= charsize || *ptr == TAB) {
         n_skip = (int)(v - vcol);
       }
     }
@@ -1798,8 +1805,10 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange,
             && !vim_isbreak((int)(*ptr))) {
           int mb_off = utf_head_off(line, ptr - 1);
           char_u *p = ptr - (mb_off + 1);
-          // TODO(neovim): is passing p for start of the line OK?
-          n_extra = win_lbr_chartabsize(wp, line, p, (colnr_T)vcol, NULL) - 1;
+          chartabsize_T cts;
+
+          init_chartabsize_arg(&cts, wp, lnum, (colnr_T)vcol, line, p);
+          n_extra = win_lbr_chartabsize(&cts, NULL) - 1;
 
           // We have just drawn the showbreak value, no need to add
           // space for it again.
@@ -1825,6 +1834,7 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange,
               c = ' ';
             }
           }
+          clear_chartabsize_arg(&cts);
         }
 
         in_multispace = c == ' ' && ((ptr > line + 1 && ptr[-2] == ' ') || *ptr == ' ');