Merge pull request #9586 from bfredl/screencleanup

screen: cleanup allocation and scrolling

src/nvim/main.c

@@ -300,7 +300,7 @@ int main(int argc, char **argv)
   assert(p_ch >= 0 && Rows >= p_ch && Rows - p_ch <= INT_MAX);
   cmdline_row = (int)(Rows - p_ch);
   msg_row = cmdline_row;
-  screenalloc(false);  // allocate screen buffers
+  screenalloc();  // allocate screen buffers
   set_init_2(headless_mode);
   TIME_MSG("inits 2");
 

src/nvim/message.c

@@ -946,9 +946,9 @@ void wait_return(int redraw)
     c = CAR;                    /* no need for a return in ex mode */
     got_int = FALSE;
   } else {
-    /* Make sure the hit-return prompt is on screen when 'guioptions' was
+    // Make sure the hit-return prompt is on screen when 'guioptions' was
-     * just changed. */
+    // just changed.
-    screenalloc(false);
+    screenalloc();
 
     State = HITRETURN;
     setmouse();
@@ -2392,9 +2392,8 @@ static int do_more_prompt(int typed_char)
               mp_last = msg_sb_start(mp_last->sb_prev);
           }
 
-          if (toscroll == -1
+          if (toscroll == -1) {
-              && grid_ins_lines(&default_grid, 0, 1, (int)Rows,
+            grid_ins_lines(&default_grid, 0, 1, (int)Rows, 0, (int)Columns);
-                                0, (int)Columns) == OK) {
             grid_fill(&default_grid, 0, 1, 0, (int)Columns, ' ', ' ', 0);
             // display line at top
             (void)disp_sb_line(0, mp);

src/nvim/move.c

@@ -152,7 +152,7 @@ void update_topline(void)
 
   // If there is no valid screen and when the window height is zero just use
   // the cursor line.
-  if (!screen_valid(true) || curwin->w_height_inner == 0) {
+  if (!default_grid.chars || curwin->w_height_inner == 0) {
     curwin->w_topline = curwin->w_cursor.lnum;
     curwin->w_botline = curwin->w_topline;
     curwin->w_valid |= VALID_BOTLINE|VALID_BOTLINE_AP;
@@ -925,12 +925,9 @@ void curs_columns(
       curwin->w_wrow -= extra;
     }
 
+    // extra could be either positive or negative
     extra = ((int)prev_skipcol - (int)curwin->w_skipcol) / width;
-    if (extra > 0) {
+    win_scroll_lines(curwin, 0, extra);
-      win_ins_lines(curwin, 0, extra);
-    } else if (extra < 0) {
-      win_del_lines(curwin, 0, -extra);
-    }
   } else {
     curwin->w_skipcol = 0;
   }

src/nvim/screen.c

@@ -274,9 +274,10 @@ void update_screen(int type)
   static int did_intro = FALSE;
   int did_one;
 
-  /* Don't do anything if the screen structures are (not yet) valid. */
+  // Don't do anything if the screen structures are (not yet) valid.
-  if (!screen_valid(TRUE))
+  if (!default_grid.chars) {
     return;
+  }
 
   if (must_redraw) {
     if (type < must_redraw)         /* use maximal type */
@@ -335,10 +336,8 @@ void update_screen(int type)
       type = CLEAR;
     } else if (type != CLEAR) {
       check_for_delay(false);
-      if (grid_ins_lines(&default_grid, 0, msg_scrolled, (int)Rows,
+      grid_ins_lines(&default_grid, 0, msg_scrolled, (int)Rows,
-                         0, (int)Columns) == FAIL) {
+                     0, (int)Columns);
-        type = CLEAR;
-      }
       FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
         if (wp->w_winrow < msg_scrolled) {
           if (W_ENDROW(wp) > msg_scrolled
@@ -828,15 +827,15 @@ static void win_update(win_T *wp)
           // Try to insert the correct number of lines.
           // If not the last window, delete the lines at the bottom.
           // win_ins_lines may fail when the terminal can't do it.
-          if (win_ins_lines(wp, 0, i) == OK) {
+          win_scroll_lines(wp, 0, i);
           if (wp->w_lines_valid != 0) {
-              /* Need to update rows that are new, stop at the
+            // Need to update rows that are new, stop at the
-               * first one that scrolled down. */
+            // first one that scrolled down.
             top_end = i;
-              scrolled_down = TRUE;
+            scrolled_down = true;
 
-              /* Move the entries that were scrolled, disable
+            // Move the entries that were scrolled, disable
-               * the entries for the lines to be redrawn. */
+            // the entries for the lines to be redrawn.
             if ((wp->w_lines_valid += j) > wp->w_grid.Rows) {
               wp->w_lines_valid = wp->w_grid.Rows;
             }
@@ -847,12 +846,12 @@ static void win_update(win_T *wp)
               wp->w_lines[idx--].wl_valid = false;
             }
           }
-          } else
+        } else {
-            mid_start = 0;                      /* redraw all lines */
+          mid_start = 0;  // redraw all lines
-        } else
+        }
-          mid_start = 0;                        /* redraw all lines */
+      } else {
-      } else
+        mid_start = 0;  // redraw all lines
-        mid_start = 0;                  /* redraw all lines */
+      }
     } else {
       /*
        * New topline is at or below old topline: May scroll up.
@@ -889,11 +888,8 @@ static void win_update(win_T *wp)
         /* ... but don't delete new filler lines. */
         row -= wp->w_topfill;
         if (row > 0) {
-          if (win_del_lines(wp, 0, row) == OK) {
+          win_scroll_lines(wp, 0, -row);
           bot_start = wp->w_grid.Rows - row;
-          } else {
-            mid_start = 0;                      // redraw all lines
-          }
         }
         if ((row == 0 || bot_start < 999) && wp->w_lines_valid != 0) {
           /*
@@ -1148,7 +1144,7 @@ static void win_update(win_T *wp)
     // Update a line when it is in an area that needs updating, when it
     // has changes or w_lines[idx] is invalid.
     // "bot_start" may be halfway a wrapped line after using
-    // win_del_lines(), check if the current line includes it.
+    // win_scroll_lines(), check if the current line includes it.
     // When syntax folding is being used, the saved syntax states will
     // already have been updated, we can't see where the syntax state is
     // the same again, just update until the end of the window.
@@ -1244,12 +1240,9 @@ static void win_update(win_T *wp)
             if (row - xtra_rows >= wp->w_grid.Rows - 2) {
               mod_bot = MAXLNUM;
             } else {
-              if (win_del_lines(wp, row, -xtra_rows) == FAIL) {
+              win_scroll_lines(wp, row, xtra_rows);
-                mod_bot = MAXLNUM;
-              } else {
               bot_start = wp->w_grid.Rows + xtra_rows;
             }
-            }
           } else if (xtra_rows > 0) {
             /* May scroll text down.  If there is not enough
              * remaining text of scrolling fails, must redraw the
@@ -1257,9 +1250,8 @@ static void win_update(win_T *wp)
             if (row + xtra_rows >= wp->w_grid.Rows - 2) {
               mod_bot = MAXLNUM;
             } else {
-              if (win_ins_lines(wp, row + old_rows, xtra_rows) == FAIL) {
+              win_scroll_lines(wp, row + old_rows, xtra_rows);
-                mod_bot = MAXLNUM;
+              if (top_end > row + old_rows) {
-              } else if (top_end > row + old_rows) {
                 // Scrolled the part at the top that requires
                 // updating down.
                 top_end += xtra_rows;
@@ -5813,7 +5805,7 @@ void grid_fill(ScreenGrid *grid, int start_row, int end_row, int start_col,
   }
 
   // nothing to do
-  if (grid->chars == NULL || start_row >= end_row || start_col >= end_col) {
+  if (start_row >= end_row || start_col >= end_col) {
     return;
   }
 
@@ -5902,18 +5894,6 @@ void check_for_delay(int check_msg_scroll)
   }
 }
 
-/*
- * screen_valid -  allocate screen buffers if size changed
- *   If "doclear" is TRUE: clear screen if it has been resized.
- *	Returns TRUE if there is a valid screen to write to.
- *	Returns FALSE when starting up and screen not initialized yet.
- */
-int screen_valid(int doclear)
-{
-  screenalloc(doclear);  // allocate screen buffers if size changed
-  return default_grid.chars != NULL;
-}
-
 /// (Re)allocates a window grid if size changed while in ext_multigrid mode.
 /// Updates size, offsets and handle for the grid regardless.
 ///
@@ -5989,7 +5969,7 @@ void grid_assign_handle(ScreenGrid *grid)
 /// default_grid.Columns to access items in default_grid.chars[].  Use Rows
 /// and Columns for positioning text etc. where the final size of the shell is
 /// needed.
-void screenalloc(bool doclear)
+void screenalloc(void)
 {
   static bool entered = false;  // avoid recursiveness
   int retry_count = 0;
@@ -6041,7 +6021,7 @@ retry:
   // Continuing with the old arrays may result in a crash, because the
   // size is wrong.
 
-  grid_alloc(&default_grid, Rows, Columns, !doclear, true);
+  grid_alloc(&default_grid, Rows, Columns, true, true);
   StlClickDefinition *new_tab_page_click_defs = xcalloc(
       (size_t)Columns, sizeof(*new_tab_page_click_defs));
 
@@ -6055,10 +6035,7 @@ retry:
   default_grid.col_offset = 0;
   default_grid.handle = DEFAULT_GRID_HANDLE;
 
-  must_redraw = CLEAR;          /* need to clear the screen later */
+  must_redraw = CLEAR;  // need to clear the screen later
-  if (doclear)
-    screenclear2();
-
 
   entered = FALSE;
   --RedrawingDisabled;
@@ -6165,13 +6142,9 @@ void clear_tab_page_click_defs(StlClickDefinition *const tpcd,
 
 void screenclear(void)
 {
-  check_for_delay(FALSE);
+  check_for_delay(false);
-  screenalloc(false);       /* allocate screen buffers if size changed */
+  screenalloc();  // allocate screen buffers if size changed
-  screenclear2();           /* clear the screen */
-}
 
-static void screenclear2(void)
-{
   int i;
 
   if (starting == NO_SCREEN || default_grid.chars == NULL) {
@@ -6265,42 +6238,28 @@ void setcursor(void)
   }
 }
 
-/// Insert 'line_count' lines at 'row' in window 'wp'.
+/// Scroll 'line_count' lines at 'row' in window 'wp'.
-/// Returns FAIL if the lines are not inserted, OK for success.
+///
-int win_ins_lines(win_T *wp, int row, int line_count)
+/// Positive `line_count' means scrolling down, so that more space is available
+/// at 'row'. Negative `line_count` implies deleting lines at `row`.
+void win_scroll_lines(win_T *wp, int row, int line_count)
 {
-  return win_do_lines(wp, row, line_count, false);
+  if (!redrawing() || line_count == 0) {
-}
+    return;
-
-/// Delete "line_count" window lines at "row" in window "wp".
-/// Return OK for success, FAIL if the lines are not deleted.
-int win_del_lines(win_T *wp, int row, int line_count)
-{
-  return win_do_lines(wp, row, line_count, true);
-}
-
-// Common code for win_ins_lines() and win_del_lines().
-// Returns OK or FAIL when the work has been done.
-static int win_do_lines(win_T *wp, int row, int line_count, int del)
-{
-  if (!redrawing() || line_count <= 0) {
-    return FAIL;
   }
 
   // No lines are being moved, just draw over the entire area
-  if (row + line_count >= wp->w_grid.Rows) {
+  if (row + abs(line_count) >= wp->w_grid.Rows) {
-    return OK;
+    return;
   }
 
-  int retval;
+  if (line_count < 0) {
-  if (del) {
+    grid_del_lines(&wp->w_grid, row, -line_count,
-    retval = grid_del_lines(&wp->w_grid, row, line_count,
                    wp->w_grid.Rows, 0, wp->w_grid.Columns);
   } else {
-    retval = grid_ins_lines(&wp->w_grid, row, line_count,
+    grid_ins_lines(&wp->w_grid, row, line_count,
                    wp->w_grid.Rows, 0, wp->w_grid.Columns);
   }
-  return retval;
 }
 
 /*
@@ -6320,9 +6279,7 @@ static int win_do_lines(win_T *wp, int row, int line_count, int del)
 /// 'col' is the column from with we start inserting.
 //
 /// 'row', 'col' and 'end' are relative to the start of the region.
-///
+void grid_ins_lines(ScreenGrid *grid, int row, int line_count, int end, int col,
-/// @return FAIL for failure, OK for success.
-int grid_ins_lines(ScreenGrid *grid, int row, int line_count, int end, int col,
                     int width)
 {
   int i;
@@ -6334,8 +6291,8 @@ int grid_ins_lines(ScreenGrid *grid, int row, int line_count, int end, int col,
   row += row_off;
   end += row_off;
 
-  if (!screen_valid(TRUE) || line_count <= 0) {
+  if (line_count <= 0) {
-    return FAIL;
+    return;
   }
 
   // Shift line_offset[] line_count down to reflect the inserted lines.
@@ -6365,16 +6322,14 @@ int grid_ins_lines(ScreenGrid *grid, int row, int line_count, int end, int col,
 
   ui_call_grid_scroll(grid->handle, row, end, col, col+width, -line_count, 0);
 
-  return OK;
+  return;
 }
 
 /// delete lines on the screen and move lines up.
 /// 'end' is the line after the scrolled part. Normally it is Rows.
 /// When scrolling region used 'off' is the offset from the top for the region.
 /// 'row' and 'end' are relative to the start of the region.
-///
+void grid_del_lines(ScreenGrid *grid, int row, int line_count, int end, int col,
-/// Return OK for success, FAIL if the lines are not deleted.
-int grid_del_lines(ScreenGrid *grid, int row, int line_count, int end, int col,
                     int width)
 {
   int j;
@@ -6386,8 +6341,8 @@ int grid_del_lines(ScreenGrid *grid, int row, int line_count, int end, int col,
   row += row_off;
   end += row_off;
 
-  if (!screen_valid(TRUE) || line_count <= 0) {
+  if (line_count <= 0) {
-    return FAIL;
+    return;
   }
 
   // Now shift line_offset[] line_count up to reflect the deleted lines.
@@ -6418,7 +6373,7 @@ int grid_del_lines(ScreenGrid *grid, int row, int line_count, int end, int col,
 
   ui_call_grid_scroll(grid->handle, row, end, col, col+width, line_count, 0);
 
-  return OK;
+  return;
 }
 
 
@@ -7186,7 +7141,7 @@ void screen_resize(int width, int height)
      */
     if (State == ASKMORE || State == EXTERNCMD || State == CONFIRM
         || exmode_active) {
-      screenalloc(false);
+      screenalloc();
       repeat_message();
     } else {
       if (curwin->w_p_scb)