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, 109 insertions, 73 deletions

diff --git a/src/nvim/plines.c b/src/nvim/plines.c
index 70bdbd8b1d..f13e83ca9b 100644
--- a/src/nvim/plines.c
+++ b/src/nvim/plines.c
@@ -98,15 +98,15 @@ int plines_win_nofill(win_T *wp, linenr_T lnum, bool winheight)
 /// "wp".  Does not care about folding, 'wrap' or 'diff'.
 int plines_win_nofold(win_T *wp, linenr_T lnum)
 {
-  char_u *s;
+  char *s;
   unsigned int col;
   int width;
 
-  s = ml_get_buf(wp->w_buffer, lnum, false);
+  s = (char *)ml_get_buf(wp->w_buffer, lnum, false);
   if (*s == NUL) {  // empty line
     return 1;
   }
-  col = win_linetabsize(wp, s, MAXCOL);
+  col = win_linetabsize(wp, lnum, (char_u *)s, MAXCOL);
 
   // If list mode is on, then the '$' at the end of the line may take up one
   // extra column.
@@ -145,23 +145,27 @@ int plines_win_col(win_T *wp, linenr_T lnum, long column)
   }
 
   char_u *line = ml_get_buf(wp->w_buffer, lnum, false);
-  char_u *s = line;
 
   colnr_T col = 0;
-  while (*s != NUL && --column >= 0) {
-    col += win_lbr_chartabsize(wp, line, s, col, NULL);
-    MB_PTR_ADV(s);
+  chartabsize_T cts;
+
+  init_chartabsize_arg(&cts, wp, lnum, 0, line, line);
+  while (*cts.cts_ptr != NUL && --column >= 0) {
+    cts.cts_vcol += win_lbr_chartabsize(&cts, NULL);
+    MB_PTR_ADV(cts.cts_ptr);
   }
 
-  // If *s is a TAB, and the TAB is not displayed as ^I, and we're not in
-  // MODE_INSERT state, then col must be adjusted so that it represents the
+  // If *cts.cts_ptr is a TAB, and the TAB is not displayed as ^I, and we're not
+  // in MODE_INSERT state, then col must be adjusted so that it represents the
   // last screen position of the TAB.  This only fixes an error when the TAB
   // wraps from one screen line to the next (when 'columns' is not a multiple
   // of 'ts') -- webb.
-  if (*s == TAB && (State & MODE_NORMAL)
+  col = cts.cts_vcol;
+  if (*cts.cts_ptr == TAB && (State & MODE_NORMAL)
       && (!wp->w_p_list || wp->w_p_lcs_chars.tab1)) {
-    col += win_lbr_chartabsize(wp, line, s, col, NULL) - 1;
+    col += win_lbr_chartabsize(&cts, NULL) - 1;
   }
+  clear_chartabsize_arg(&cts);
 
   // Add column offset for 'number', 'relativenumber', 'foldcolumn', etc.
   int width = wp->w_width_inner - win_col_off(wp);
@@ -223,7 +227,7 @@ int plines_m_win(win_T *wp, linenr_T first, linenr_T last)
 /// @param col
 ///
 /// @return Number of characters.
-int win_chartabsize(win_T *wp, char_u *p, colnr_T col)
+int win_chartabsize(win_T *wp, char *p, colnr_T col)
 {
   buf_T *buf = wp->w_buffer;
   if (*p == TAB && (!wp->w_p_list || wp->w_p_lcs_chars.tab1)) {
@@ -241,24 +245,24 @@ int win_chartabsize(win_T *wp, char_u *p, colnr_T col)
 /// @return Number of characters the string will take on the screen.
 int linetabsize(char_u *s)
 {
-  return linetabsize_col(0, s);
+  return linetabsize_col(0, (char *)s);
 }
 
-/// Like linetabsize(), but starting at column "startcol".
+/// Like linetabsize(), but "s" starts at column "startcol".
 ///
 /// @param startcol
 /// @param s
 ///
 /// @return Number of characters the string will take on the screen.
-int linetabsize_col(int startcol, char_u *s)
+int linetabsize_col(int startcol, char *s)
 {
-  colnr_T col = startcol;
-  char_u *line = s;  // pointer to start of line, for breakindent
-
-  while (*s != NUL) {
-    col += lbr_chartabsize_adv(line, &s, col);
+  chartabsize_T cts;
+  init_chartabsize_arg(&cts, curwin, 0, startcol, (char_u *)s, (char_u *)s);
+  while (*cts.cts_ptr != NUL) {
+    cts.cts_vcol += lbr_chartabsize_adv(&cts);
   }
-  return (int)col;
+  clear_chartabsize_arg(&cts);
+  return (int)cts.cts_vcol;
 }
 
 /// Like linetabsize(), but for a given window instead of the current one.
@@ -268,19 +272,39 @@ int linetabsize_col(int startcol, char_u *s)
 /// @param len
 ///
 /// @return Number of characters the string will take on the screen.
-unsigned int win_linetabsize(win_T *wp, char_u *line, colnr_T len)
+unsigned int win_linetabsize(win_T *wp, linenr_T lnum, char_u *line, colnr_T len)
 {
-  colnr_T col = 0;
-
-  for (char_u *s = line;
-       *s != NUL && (len == MAXCOL || s < line + len);
-       MB_PTR_ADV(s)) {
-    col += win_lbr_chartabsize(wp, line, s, col, NULL);
+  chartabsize_T cts;
+  init_chartabsize_arg(&cts, wp, lnum, 0, line, line);
+  for (; *cts.cts_ptr != NUL && (len == MAXCOL || cts.cts_ptr < (char *)line + len);
+       MB_PTR_ADV(cts.cts_ptr)) {
+    cts.cts_vcol += win_lbr_chartabsize(&cts, NULL);
   }
+  clear_chartabsize_arg(&cts);
+  return (unsigned int)cts.cts_vcol;
+}
 
-  return (unsigned int)col;
+/// Prepare the structure passed to chartabsize functions.
+///
+/// "line" is the start of the line, "ptr" is the first relevant character.
+/// When "lnum" is zero do not use text properties that insert text.
+void init_chartabsize_arg(chartabsize_T *cts, win_T *wp, linenr_T lnum, colnr_T col, char_u *line,
+                          char_u *ptr)
+{
+  cts->cts_win = wp;
+  cts->cts_lnum = lnum;
+  cts->cts_vcol = col;
+  cts->cts_line = (char *)line;
+  cts->cts_ptr = (char *)ptr;
+  cts->cts_cur_text_width = 0;
+  // TODO(bfredl): actually lookup inline virtual text here
+  cts->cts_has_virt_text = false;
 }
 
+/// Free any allocated item in "cts".
+void clear_chartabsize_arg(chartabsize_T *cts)
+{}
+
 /// like win_chartabsize(), but also check for line breaks on the screen
 ///
 /// @param line
@@ -288,16 +312,16 @@ unsigned int win_linetabsize(win_T *wp, char_u *line, colnr_T len)
 /// @param col
 ///
 /// @return The number of characters taken up on the screen.
-int lbr_chartabsize(char_u *line, unsigned char *s, colnr_T col)
+int lbr_chartabsize(chartabsize_T *cts)
 {
   if (!curwin->w_p_lbr && *get_showbreak_value(curwin) == NUL
-      && !curwin->w_p_bri) {
+      && !curwin->w_p_bri && !cts->cts_has_virt_text) {
     if (curwin->w_p_wrap) {
-      return win_nolbr_chartabsize(curwin, s, col, NULL);
+      return win_nolbr_chartabsize(cts, NULL);
     }
-    return win_chartabsize(curwin, s, col);
+    return win_chartabsize(curwin, cts->cts_ptr, cts->cts_vcol);
   }
-  return win_lbr_chartabsize(curwin, line == NULL ? s: line, s, col, NULL);
+  return win_lbr_chartabsize(cts, NULL);
 }
 
 /// Call lbr_chartabsize() and advance the pointer.
@@ -307,12 +331,12 @@ int lbr_chartabsize(char_u *line, unsigned char *s, colnr_T col)
 /// @param col
 ///
 /// @return The number of characters take up on the screen.
-int lbr_chartabsize_adv(char_u *line, char_u **s, colnr_T col)
+int lbr_chartabsize_adv(chartabsize_T *cts)
 {
   int retval;
 
-  retval = lbr_chartabsize(line, *s, col);
-  MB_PTR_ADV(*s);
+  retval = lbr_chartabsize(cts);
+  MB_PTR_ADV(cts->cts_ptr);
   return retval;
 }
 
@@ -322,17 +346,19 @@ int lbr_chartabsize_adv(char_u *line, char_u **s, colnr_T col)
 /// string at start of line.  Warning: *headp is only set if it's a non-zero
 /// value, init to 0 before calling.
 ///
-/// @param wp
-/// @param line
-/// @param s
-/// @param col
+/// @param cts
 /// @param headp
 ///
 /// @return The number of characters taken up on the screen.
-int win_lbr_chartabsize(win_T *wp, char_u *line, char_u *s, colnr_T col, int *headp)
+int win_lbr_chartabsize(chartabsize_T *cts, int *headp)
 {
+  win_T *wp = cts->cts_win;
+  char *line = cts->cts_line;  // start of the line
+  char_u *s = (char_u *)cts->cts_ptr;
+  colnr_T vcol = cts->cts_vcol;
+
   colnr_T col2;
-  colnr_T col_adj = 0;  // col + screen size of tab
+  colnr_T col_adj = 0;  // vcol + screen size of tab
   colnr_T colmax;
   int added;
   int mb_added = 0;
@@ -340,16 +366,23 @@ int win_lbr_chartabsize(win_T *wp, char_u *line, char_u *s, colnr_T col, int *he
   char_u *ps;
   int n;
 
+  cts->cts_cur_text_width = 0;
+
   // No 'linebreak', 'showbreak' and 'breakindent': return quickly.
-  if (!wp->w_p_lbr && !wp->w_p_bri && *get_showbreak_value(wp) == NUL) {
+  if (!wp->w_p_lbr && !wp->w_p_bri && *get_showbreak_value(wp) == NUL
+      && !cts->cts_has_virt_text) {
     if (wp->w_p_wrap) {
-      return win_nolbr_chartabsize(wp, s, col, headp);
+      return win_nolbr_chartabsize(cts, headp);
     }
-    return win_chartabsize(wp, s, col);
+    return win_chartabsize(wp, (char *)s, vcol);
+  }
+
+  // First get normal size, without 'linebreak' or virtual text
+  int size = win_chartabsize(wp, (char *)s, vcol);
+  if (cts->cts_has_virt_text) {
+    // TODO(bfredl): inline virtual text
   }
 
-  // First get normal size, without 'linebreak'
-  int size = win_chartabsize(wp, s, col);
   int c = *s;
   if (*s == TAB) {
     col_adj = size - 1;
@@ -365,15 +398,15 @@ int win_lbr_chartabsize(win_T *wp, char_u *line, char_u *s, colnr_T col, int *he
     // Count all characters from first non-blank after a blank up to next
     // non-blank after a blank.
     numberextra = win_col_off(wp);
-    col2 = col;
+    col2 = vcol;
     colmax = (colnr_T)(wp->w_width_inner - numberextra - col_adj);
 
-    if (col >= colmax) {
+    if (vcol >= colmax) {
       colmax += col_adj;
       n = colmax + win_col_off2(wp);
 
       if (n > 0) {
-        colmax += (((col - colmax) / n) + 1) * n - col_adj;
+        colmax += (((vcol - colmax) / n) + 1) * n - col_adj;
       }
     }
 
@@ -383,21 +416,21 @@ int win_lbr_chartabsize(win_T *wp, char_u *line, char_u *s, colnr_T col, int *he
       c = *s;
 
       if (!(c != NUL
-            && (vim_isbreak(c) || col2 == col || !vim_isbreak((int)(*ps))))) {
+            && (vim_isbreak(c) || col2 == vcol || !vim_isbreak((int)(*ps))))) {
         break;
       }
 
-      col2 += win_chartabsize(wp, s, col2);
+      col2 += win_chartabsize(wp, (char *)s, col2);
 
       if (col2 >= colmax) {  // doesn't fit
-        size = colmax - col + col_adj;
+        size = colmax - vcol + col_adj;
         break;
       }
     }
   } else if ((size == 2)
              && (MB_BYTE2LEN(*s) > 1)
              && wp->w_p_wrap
-             && in_win_border(wp, col)) {
+             && in_win_border(wp, vcol)) {
     // Count the ">" in the last column.
     size++;
     mb_added = 1;
@@ -409,40 +442,40 @@ int win_lbr_chartabsize(win_T *wp, char_u *line, char_u *s, colnr_T col, int *he
   added = 0;
 
   char *const sbr = (char *)get_showbreak_value(wp);
-  if ((*sbr != NUL || wp->w_p_bri) && wp->w_p_wrap && col != 0) {
+  if ((*sbr != NUL || wp->w_p_bri) && wp->w_p_wrap && vcol != 0) {
     colnr_T sbrlen = 0;
     int numberwidth = win_col_off(wp);
 
     numberextra = numberwidth;
-    col += numberextra + mb_added;
+    vcol += numberextra + mb_added;
 
-    if (col >= (colnr_T)wp->w_width_inner) {
-      col -= wp->w_width_inner;
+    if (vcol >= (colnr_T)wp->w_width_inner) {
+      vcol -= wp->w_width_inner;
       numberextra = wp->w_width_inner - (numberextra - win_col_off2(wp));
-      if (col >= numberextra && numberextra > 0) {
-        col %= numberextra;
+      if (vcol >= numberextra && numberextra > 0) {
+        vcol %= numberextra;
       }
       if (*sbr != NUL) {
         sbrlen = (colnr_T)mb_charlen((char_u *)sbr);
-        if (col >= sbrlen) {
-          col -= sbrlen;
+        if (vcol >= sbrlen) {
+          vcol -= sbrlen;
         }
       }
-      if (col >= numberextra && numberextra > 0) {
-        col %= numberextra;
-      } else if (col > 0 && numberextra > 0) {
-        col += numberwidth - win_col_off2(wp);
+      if (vcol >= numberextra && numberextra > 0) {
+        vcol %= numberextra;
+      } else if (vcol > 0 && numberextra > 0) {
+        vcol += numberwidth - win_col_off2(wp);
       }
 
       numberwidth -= win_col_off2(wp);
     }
 
-    if (col == 0 || (col + size + sbrlen > (colnr_T)wp->w_width_inner)) {
+    if (vcol == 0 || (vcol + size + sbrlen > (colnr_T)wp->w_width_inner)) {
       if (*sbr != NUL) {
         if (size + sbrlen + numberwidth > (colnr_T)wp->w_width_inner) {
           // Calculate effective window width.
           int width = (colnr_T)wp->w_width_inner - sbrlen - numberwidth;
-          int prev_width = col ? ((colnr_T)wp->w_width_inner - (sbrlen + col))
+          int prev_width = vcol ? ((colnr_T)wp->w_width_inner - (sbrlen + vcol))
                                : 0;
 
           if (width <= 0) {
@@ -459,11 +492,11 @@ int win_lbr_chartabsize(win_T *wp, char_u *line, char_u *s, colnr_T col, int *he
       }
 
       if (wp->w_p_bri) {
-        added += get_breakindent_win(wp, line);
+        added += get_breakindent_win(wp, (char_u *)line);
       }
 
       size += added;
-      if (col != 0) {
+      if (vcol != 0) {
         added = 0;
       }
     }
@@ -485,8 +518,11 @@ int win_lbr_chartabsize(win_T *wp, char_u *line, char_u *s, colnr_T col, int *he
 /// @param headp
 ///
 /// @return The number of characters take up on the screen.
-static int win_nolbr_chartabsize(win_T *wp, char_u *s, colnr_T col, int *headp)
+static int win_nolbr_chartabsize(chartabsize_T *cts, int *headp)
 {
+  win_T *wp = cts->cts_win;
+  char *s = cts->cts_ptr;
+  colnr_T col = cts->cts_vcol;
   int n;
 
   if ((*s == TAB) && (!wp->w_p_list || wp->w_p_lcs_chars.tab1)) {
@@ -498,7 +534,7 @@ static int win_nolbr_chartabsize(win_T *wp, char_u *s, colnr_T col, int *headp)
 
   // Add one cell for a double-width character in the last column of the
   // window, displayed with a ">".
-  if ((n == 2) && (MB_BYTE2LEN(*s) > 1) && in_win_border(wp, col)) {
+  if ((n == 2) && (MB_BYTE2LEN((uint8_t)(*s)) > 1) && in_win_border(wp, col)) {
     if (headp != NULL) {
       *headp = 1;
     }