refactor(grid): properly namespace and separate stateful grid functions

This is a step in an ongoing refactor where the "grid_puts" and
"grid_put_linebuf" code paths will share more of the implementation (in
particular for delta calculation, doublewidth and 'arabicshape'
handling). But it also makes sense by its own as a cleanup, and is thus
committed separately.

Before this change many of the low level grid functions grid_puts,
grid_fill etc could both be used in a standalone fashion but also as
part of a batched line update which would be finally transmitted as a
single grid_line call (via ui_line() ). This was initially useful to
quickly refactor pre-existing vim code to use batched logic safely.

However, this pattern is not really helpful for maintainable and newly
written code, where the "grid" and "row" arguments are just needlessly
repeated. This simplifies these calls to just use grid and row as
specified in the initial grid_line_start(grid, row) call.

This also makes the intent clear whether any grid_puts() call is actually
part of a batch or not, which is better in the long run when more things
get refactored to use effective (properly batched) updates.

1 files changed, 40 insertions, 42 deletions

diff --git a/src/nvim/drawscreen.c b/src/nvim/drawscreen.c
index 1d22b67d40..ee1f03e296 100644
--- a/src/nvim/drawscreen.c
+++ b/src/nvim/drawscreen.c
@@ -709,7 +709,7 @@ void end_search_hl(void)
   screen_search_hl.rm.regprog = NULL;
 }
 
-static void win_redr_bordertext(win_T *wp, ScreenGrid *grid, VirtText vt, int row, int col)
+static void win_redr_bordertext(win_T *wp, VirtText vt, int col)
 {
   for (size_t i = 0; i < kv_size(vt);) {
     int attr = 0;
@@ -717,9 +717,7 @@ static void win_redr_bordertext(win_T *wp, ScreenGrid *grid, VirtText vt, int ro
     if (text == NULL) {
       break;
     }
-    int cell = (int)mb_string2cells(text);
-    grid_puts(grid, text, row, col, attr);
-    col += cell;
+    col += grid_line_puts(col, text, -1, attr);
   }
 }
 
@@ -756,60 +754,60 @@ static void win_redr_border(win_T *wp)
   int irow = wp->w_height_inner + wp->w_winbar_height, icol = wp->w_width_inner;
 
   if (adj[0]) {
-    grid_puts_line_start(grid, 0);
+    grid_line_start(grid, 0);
     if (adj[3]) {
-      grid_put_schar(grid, 0, 0, chars[0], attrs[0]);
+      grid_line_put_schar(0, chars[0], attrs[0]);
     }
 
     for (int i = 0; i < icol; i++) {
-      grid_put_schar(grid, 0, i + adj[3], chars[1], attrs[1]);
+      grid_line_put_schar(i + adj[3], chars[1], attrs[1]);
     }
 
     if (wp->w_float_config.title) {
       int title_col = win_get_bordertext_col(icol, wp->w_float_config.title_width,
                                              wp->w_float_config.title_pos);
-      win_redr_bordertext(wp, grid, wp->w_float_config.title_chunks, 0, title_col);
+      win_redr_bordertext(wp, wp->w_float_config.title_chunks, title_col);
     }
     if (adj[1]) {
-      grid_put_schar(grid, 0, icol + adj[3], chars[2], attrs[2]);
+      grid_line_put_schar(icol + adj[3], chars[2], attrs[2]);
     }
-    grid_puts_line_flush(false);
+    grid_line_flush(false);
   }
 
   for (int i = 0; i < irow; i++) {
     if (adj[3]) {
-      grid_puts_line_start(grid, i + adj[0]);
-      grid_put_schar(grid, i + adj[0], 0, chars[7], attrs[7]);
-      grid_puts_line_flush(false);
+      grid_line_start(grid, i + adj[0]);
+      grid_line_put_schar(0, chars[7], attrs[7]);
+      grid_line_flush(false);
     }
     if (adj[1]) {
       int ic = (i == 0 && !adj[0] && chars[2]) ? 2 : 3;
-      grid_puts_line_start(grid, i + adj[0]);
-      grid_put_schar(grid, i + adj[0], icol + adj[3], chars[ic], attrs[ic]);
-      grid_puts_line_flush(false);
+      grid_line_start(grid, i + adj[0]);
+      grid_line_put_schar(icol + adj[3], chars[ic], attrs[ic]);
+      grid_line_flush(false);
     }
   }
 
   if (adj[2]) {
-    grid_puts_line_start(grid, irow + adj[0]);
+    grid_line_start(grid, irow + adj[0]);
     if (adj[3]) {
-      grid_put_schar(grid, irow + adj[0], 0, chars[6], attrs[6]);
+      grid_line_put_schar(0, chars[6], attrs[6]);
     }
 
     for (int i = 0; i < icol; i++) {
       int ic = (i == 0 && !adj[3] && chars[6]) ? 6 : 5;
-      grid_put_schar(grid, irow + adj[0], i + adj[3], chars[ic], attrs[ic]);
+      grid_line_put_schar(i + adj[3], chars[ic], attrs[ic]);
     }
 
     if (wp->w_float_config.footer) {
       int footer_col = win_get_bordertext_col(icol, wp->w_float_config.footer_width,
                                               wp->w_float_config.footer_pos);
-      win_redr_bordertext(wp, grid, wp->w_float_config.footer_chunks, grid->rows - 1, footer_col);
+      win_redr_bordertext(wp, wp->w_float_config.footer_chunks, footer_col);
     }
     if (adj[1]) {
-      grid_put_schar(grid, irow + adj[0], icol + adj[3], chars[4], attrs[4]);
+      grid_line_put_schar(icol + adj[3], chars[4], attrs[4]);
     }
-    grid_puts_line_flush(false);
+    grid_line_flush(false);
   }
 }
 
@@ -932,7 +930,9 @@ int showmode(void)
                      || (State & MODE_INSERT)
                      || restart_edit != NUL
                      || VIsual_active));
-  if (do_mode || reg_recording != 0) {
+
+  bool can_show_mode = (p_ch != 0 || ui_has(kUIMessages));
+  if ((do_mode || reg_recording != 0) && can_show_mode) {
     int sub_attr;
     if (skip_showmode()) {
       return 0;  // show mode later
@@ -1307,23 +1307,25 @@ static void draw_hsep_win(win_T *wp)
 }
 
 /// Get the separator connector for specified window corner of window "wp"
-static int get_corner_sep_connector(win_T *wp, WindowCorner corner)
+static schar_T get_corner_sep_connector(win_T *wp, WindowCorner corner)
 {
   // It's impossible for windows to be connected neither vertically nor horizontally
   // So if they're not vertically connected, assume they're horizontally connected
+  int c;
   if (vsep_connected(wp, corner)) {
     if (hsep_connected(wp, corner)) {
-      return wp->w_p_fcs_chars.verthoriz;
+      c = wp->w_p_fcs_chars.verthoriz;
     } else if (corner == WC_TOP_LEFT || corner == WC_BOTTOM_LEFT) {
-      return wp->w_p_fcs_chars.vertright;
+      c = wp->w_p_fcs_chars.vertright;
     } else {
-      return wp->w_p_fcs_chars.vertleft;
+      c = wp->w_p_fcs_chars.vertleft;
     }
   } else if (corner == WC_TOP_LEFT || corner == WC_TOP_RIGHT) {
-    return wp->w_p_fcs_chars.horizdown;
+    c = wp->w_p_fcs_chars.horizdown;
   } else {
-    return wp->w_p_fcs_chars.horizup;
+    c = wp->w_p_fcs_chars.horizup;
   }
+  return schar_from_char(c);
 }
 
 /// Draw separator connecting characters on the corners of window "wp"
@@ -1366,28 +1368,24 @@ static void draw_sep_connectors_win(win_T *wp)
   bool bot_right = !(win_at_bottom || win_at_right);
 
   if (top_left || top_right) {
-    grid_puts_line_start(&default_grid, wp->w_winrow - 1);
+    grid_line_start(&default_grid, wp->w_winrow - 1);
     if (top_left) {
-      grid_putchar(&default_grid, get_corner_sep_connector(wp, WC_TOP_LEFT),
-                   wp->w_winrow - 1, wp->w_wincol - 1, hl);
+      grid_line_put_schar(wp->w_wincol - 1, get_corner_sep_connector(wp, WC_TOP_LEFT), hl);
     }
     if (top_right) {
-      grid_putchar(&default_grid, get_corner_sep_connector(wp, WC_TOP_RIGHT),
-                   wp->w_winrow - 1, W_ENDCOL(wp), hl);
+      grid_line_put_schar(W_ENDCOL(wp), get_corner_sep_connector(wp, WC_TOP_RIGHT), hl);
     }
-    grid_puts_line_flush(false);
+    grid_line_flush(false);
   }
   if (bot_left || bot_right) {
-    grid_puts_line_start(&default_grid, W_ENDROW(wp));
+    grid_line_start(&default_grid, W_ENDROW(wp));
     if (bot_left) {
-      grid_putchar(&default_grid, get_corner_sep_connector(wp, WC_BOTTOM_LEFT),
-                   W_ENDROW(wp), wp->w_wincol - 1, hl);
+      grid_line_put_schar(wp->w_wincol - 1, get_corner_sep_connector(wp, WC_BOTTOM_LEFT), hl);
     }
     if (bot_right) {
-      grid_putchar(&default_grid, get_corner_sep_connector(wp, WC_BOTTOM_RIGHT),
-                   W_ENDROW(wp), W_ENDCOL(wp), hl);
+      grid_line_put_schar(W_ENDCOL(wp), get_corner_sep_connector(wp, WC_BOTTOM_RIGHT), hl);
     }
-    grid_puts_line_flush(false);
+    grid_line_flush(false);
   }
 }
 
@@ -2384,7 +2382,7 @@ static void win_update(win_T *wp, DecorProviders *providers)
       utf_char2bytes(symbol, &fillbuf[charlen]);
 
       // Last line isn't finished: Display "@@@" in the last screen line.
-      grid_puts_len(&wp->w_grid, fillbuf, MIN(wp->w_grid.cols, 2) * charlen, scr_row, 0, at_attr);
+      grid_puts(&wp->w_grid, fillbuf, MIN(wp->w_grid.cols, 2) * charlen, scr_row, 0, at_attr);
       grid_fill(&wp->w_grid, scr_row, scr_row + 1, 2, wp->w_grid.cols, symbol, ' ', at_attr);
       set_empty_rows(wp, srow);
       wp->w_botline = lnum;