Merge branch 'master' of https://github.com/neovim/neovim into rahmtmp

1 files changed, 2706 insertions, 0 deletions

diff --git a/src/nvim/drawline.c b/src/nvim/drawline.c
new file mode 100644
index 0000000000..95026ff8ed
--- /dev/null
+++ b/src/nvim/drawline.c
@@ -0,0 +1,2706 @@
+// This is an open source non-commercial project. Dear PVS-Studio, please check
+// it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+
+// drawline.c: Functions for drawing window lines on the screen.
+// This is the middle level, drawscreen.c is the top and grid.c/screen.c the lower level.
+
+#include <assert.h>
+#include <inttypes.h>
+#include <stdbool.h>
+#include <string.h>
+
+#include "nvim/arabic.h"
+#include "nvim/buffer.h"
+#include "nvim/charset.h"
+#include "nvim/cursor.h"
+#include "nvim/cursor_shape.h"
+#include "nvim/diff.h"
+#include "nvim/drawline.h"
+#include "nvim/fold.h"
+#include "nvim/grid.h"
+#include "nvim/highlight.h"
+#include "nvim/highlight_group.h"
+#include "nvim/indent.h"
+#include "nvim/match.h"
+#include "nvim/move.h"
+#include "nvim/option.h"
+#include "nvim/plines.h"
+#include "nvim/quickfix.h"
+#include "nvim/search.h"
+#include "nvim/sign.h"
+#include "nvim/spell.h"
+#include "nvim/state.h"
+#include "nvim/syntax.h"
+#include "nvim/undo.h"
+#include "nvim/window.h"
+
+#define MB_FILLER_CHAR '<'  // character used when a double-width character
+                            // doesn't fit.
+
+/// for line_putchar. Contains the state that needs to be remembered from
+/// putting one character to the next.
+typedef struct {
+  const char *p;
+  int prev_c;   ///< previous Arabic character
+  int prev_c1;  ///< first composing char for prev_c
+} LineState;
+#define LINE_STATE(p) { p, 0, 0 }
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "drawline.c.generated.h"
+#endif
+
+/// Advance **color_cols
+///
+/// @return  true when there are columns to draw.
+static bool advance_color_col(int vcol, int **color_cols)
+{
+  while (**color_cols >= 0 && vcol > **color_cols) {
+    (*color_cols)++;
+  }
+  return **color_cols >= 0;
+}
+
+/// Used when 'cursorlineopt' contains "screenline": compute the margins between
+/// which the highlighting is used.
+static void margin_columns_win(win_T *wp, int *left_col, int *right_col)
+{
+  // cache previous calculations depending on w_virtcol
+  static int saved_w_virtcol;
+  static win_T *prev_wp;
+  static int prev_left_col;
+  static int prev_right_col;
+  static int prev_col_off;
+
+  int cur_col_off = win_col_off(wp);
+  int width1;
+  int width2;
+
+  if (saved_w_virtcol == wp->w_virtcol && prev_wp == wp
+      && prev_col_off == cur_col_off) {
+    *right_col = prev_right_col;
+    *left_col = prev_left_col;
+    return;
+  }
+
+  width1 = wp->w_width - cur_col_off;
+  width2 = width1 + win_col_off2(wp);
+
+  *left_col = 0;
+  *right_col = width1;
+
+  if (wp->w_virtcol >= (colnr_T)width1) {
+    *right_col = width1 + ((wp->w_virtcol - width1) / width2 + 1) * width2;
+  }
+  if (wp->w_virtcol >= (colnr_T)width1 && width2 > 0) {
+    *left_col = (wp->w_virtcol - width1) / width2 * width2 + width1;
+  }
+
+  // cache values
+  prev_left_col = *left_col;
+  prev_right_col = *right_col;
+  prev_wp = wp;
+  saved_w_virtcol = wp->w_virtcol;
+  prev_col_off = cur_col_off;
+}
+
+/// Put a single char from an UTF-8 buffer into a line buffer.
+///
+/// Handles composing chars and arabic shaping state.
+static int line_putchar(buf_T *buf, LineState *s, schar_T *dest, int maxcells, bool rl, int vcol)
+{
+  const char_u *p = (char_u *)s->p;
+  int cells = utf_ptr2cells((char *)p);
+  int c_len = utfc_ptr2len((char *)p);
+  int u8c, u8cc[MAX_MCO];
+  if (cells > maxcells) {
+    return -1;
+  }
+  u8c = utfc_ptr2char(p, u8cc);
+  if (*p == TAB) {
+    cells = MIN(tabstop_padding(vcol, buf->b_p_ts, buf->b_p_vts_array), maxcells);
+    for (int c = 0; c < cells; c++) {
+      schar_from_ascii(dest[c], ' ');
+    }
+    goto done;
+  } else if (*p < 0x80 && u8cc[0] == 0) {
+    schar_from_ascii(dest[0], (char)(*p));
+    s->prev_c = u8c;
+  } else {
+    if (p_arshape && !p_tbidi && ARABIC_CHAR(u8c)) {
+      // Do Arabic shaping.
+      int pc, pc1, nc;
+      int pcc[MAX_MCO];
+      int firstbyte = *p;
+
+      // The idea of what is the previous and next
+      // character depends on 'rightleft'.
+      if (rl) {
+        pc = s->prev_c;
+        pc1 = s->prev_c1;
+        nc = utf_ptr2char((char *)p + c_len);
+        s->prev_c1 = u8cc[0];
+      } else {
+        pc = utfc_ptr2char(p + c_len, pcc);
+        nc = s->prev_c;
+        pc1 = pcc[0];
+      }
+      s->prev_c = u8c;
+
+      u8c = arabic_shape(u8c, &firstbyte, &u8cc[0], pc, pc1, nc);
+    } else {
+      s->prev_c = u8c;
+    }
+    schar_from_cc(dest[0], u8c, u8cc);
+  }
+  if (cells > 1) {
+    dest[1][0] = 0;
+  }
+done:
+  s->p += c_len;
+  return cells;
+}
+
+static inline void provider_err_virt_text(linenr_T lnum, char *err)
+{
+  Decoration err_decor = DECORATION_INIT;
+  int hl_err = syn_check_group(S_LEN("ErrorMsg"));
+  kv_push(err_decor.virt_text,
+          ((VirtTextChunk){ .text = err,
+                            .hl_id = hl_err }));
+  err_decor.virt_text_width = (int)mb_string2cells(err);
+  decor_add_ephemeral(lnum - 1, 0, lnum - 1, 0, &err_decor, 0, 0);
+}
+
+static void draw_virt_text(win_T *wp, buf_T *buf, int col_off, int *end_col, int max_col,
+                           int win_row)
+{
+  DecorState *state = &decor_state;
+  int right_pos = max_col;
+  bool do_eol = state->eol_col > -1;
+  for (size_t i = 0; i < kv_size(state->active); i++) {
+    DecorRange *item = &kv_A(state->active, i);
+    if (!(item->start_row == state->row
+          && (kv_size(item->decor.virt_text) || item->decor.ui_watched))) {
+      continue;
+    }
+    if (item->win_col == -1) {
+      if (item->decor.virt_text_pos == kVTRightAlign) {
+        right_pos -= item->decor.virt_text_width;
+        item->win_col = right_pos;
+      } else if (item->decor.virt_text_pos == kVTEndOfLine && do_eol) {
+        item->win_col = state->eol_col;
+      } else if (item->decor.virt_text_pos == kVTWinCol) {
+        item->win_col = MAX(item->decor.col + col_off, 0);
+      }
+    }
+    if (item->win_col < 0) {
+      continue;
+    }
+    int col;
+    if (item->decor.ui_watched) {
+      // send mark position to UI
+      col = item->win_col;
+      WinExtmark m = { (NS)item->ns_id, item->mark_id, win_row, col };
+      kv_push(win_extmark_arr, m);
+    }
+    if (kv_size(item->decor.virt_text)) {
+      col = draw_virt_text_item(buf, item->win_col, item->decor.virt_text,
+                                item->decor.hl_mode, max_col, item->win_col - col_off);
+    }
+    item->win_col = -2;  // deactivate
+    if (item->decor.virt_text_pos == kVTEndOfLine && do_eol) {
+      state->eol_col = col + 1;
+    }
+
+    *end_col = MAX(*end_col, col);
+  }
+}
+
+static int draw_virt_text_item(buf_T *buf, int col, VirtText vt, HlMode hl_mode, int max_col,
+                               int vcol)
+{
+  LineState s = LINE_STATE("");
+  int virt_attr = 0;
+  size_t virt_pos = 0;
+
+  while (col < max_col) {
+    if (!*s.p) {
+      if (virt_pos >= kv_size(vt)) {
+        break;
+      }
+      virt_attr = 0;
+      do {
+        s.p = kv_A(vt, virt_pos).text;
+        int hl_id = kv_A(vt, virt_pos).hl_id;
+        virt_attr = hl_combine_attr(virt_attr,
+                                    hl_id > 0 ? syn_id2attr(hl_id) : 0);
+        virt_pos++;
+      } while (!s.p && virt_pos < kv_size(vt));
+      if (!s.p) {
+        break;
+      }
+    }
+    if (!*s.p) {
+      continue;
+    }
+    int attr;
+    bool through = false;
+    if (hl_mode == kHlModeCombine) {
+      attr = hl_combine_attr(linebuf_attr[col], virt_attr);
+    } else if (hl_mode == kHlModeBlend) {
+      through = (*s.p == ' ');
+      attr = hl_blend_attrs(linebuf_attr[col], virt_attr, &through);
+    } else {
+      attr = virt_attr;
+    }
+    schar_T dummy[2];
+    int cells = line_putchar(buf, &s, through ? dummy : &linebuf_char[col],
+                             max_col - col, false, vcol);
+    // if we failed to emit a char, we still need to advance
+    cells = MAX(cells, 1);
+
+    for (int c = 0; c < cells; c++) {
+      linebuf_attr[col++] = attr;
+    }
+    vcol += cells;
+  }
+  return col;
+}
+
+/// Return true if CursorLineSign highlight is to be used.
+static bool use_cursor_line_sign(win_T *wp, linenr_T lnum)
+{
+  return wp->w_p_cul
+         && lnum == wp->w_cursor.lnum
+         && (wp->w_p_culopt_flags & CULOPT_NBR);
+}
+
+// Get information needed to display the sign in line 'lnum' in window 'wp'.
+// If 'nrcol' is TRUE, the sign is going to be displayed in the number column.
+// Otherwise the sign is going to be displayed in the sign column.
+//
+// @param count max number of signs
+// @param[out] n_extrap number of characters from pp_extra to display
+// @param sign_idxp Index of the displayed sign
+static void get_sign_display_info(bool nrcol, win_T *wp, linenr_T lnum, SignTextAttrs sattrs[],
+                                  int row, int startrow, int filler_lines, int filler_todo,
+                                  int *c_extrap, int *c_finalp, char_u *extra, size_t extra_size,
+                                  char_u **pp_extra, int *n_extrap, int *char_attrp, int sign_idx,
+                                  int cul_attr)
+{
+  // Draw cells with the sign value or blank.
+  *c_extrap = ' ';
+  *c_finalp = NUL;
+  if (nrcol) {
+    *n_extrap = number_width(wp) + 1;
+  } else {
+    if (use_cursor_line_sign(wp, lnum)) {
+      *char_attrp = win_hl_attr(wp, HLF_CLS);
+    } else {
+      *char_attrp = win_hl_attr(wp, HLF_SC);
+    }
+    *n_extrap = win_signcol_width(wp);
+  }
+
+  if (row == startrow + filler_lines && filler_todo <= 0) {
+    SignTextAttrs *sattr = sign_get_attr(sign_idx, sattrs, wp->w_scwidth);
+    if (sattr != NULL) {
+      *pp_extra = sattr->text;
+      if (*pp_extra != NULL) {
+        *c_extrap = NUL;
+        *c_finalp = NUL;
+
+        if (nrcol) {
+          int n, width = number_width(wp) - 2;
+          for (n = 0; n < width; n++) {
+            extra[n] = ' ';
+          }
+          extra[n] = NUL;
+          STRCAT(extra, *pp_extra);
+          STRCAT(extra, " ");
+          *pp_extra = extra;
+          *n_extrap = (int)STRLEN(*pp_extra);
+        } else {
+          size_t symbol_blen = STRLEN(*pp_extra);
+
+          // TODO(oni-link): Is sign text already extended to
+          // full cell width?
+          assert((size_t)win_signcol_width(wp) >= mb_string2cells((char *)(*pp_extra)));
+          // symbol(s) bytes + (filling spaces) (one byte each)
+          *n_extrap = (int)symbol_blen + win_signcol_width(wp) -
+                      (int)mb_string2cells((char *)(*pp_extra));
+
+          assert(extra_size > symbol_blen);
+          memset(extra, ' ', extra_size);
+          memcpy(extra, *pp_extra, symbol_blen);
+
+          *pp_extra = extra;
+          (*pp_extra)[*n_extrap] = NUL;
+        }
+      }
+
+      if (use_cursor_line_sign(wp, lnum) && cul_attr > 0) {
+        *char_attrp = cul_attr;
+      } else {
+        *char_attrp = sattr->hl_attr_id;
+      }
+    }
+  }
+}
+
+static int get_sign_attrs(buf_T *buf, linenr_T lnum, SignTextAttrs *sattrs, int *line_attr,
+                          int *num_attr, int *cul_attr)
+{
+  HlPriAttr line_attrs = { *line_attr, 0 };
+  HlPriAttr num_attrs  = { *num_attr,  0 };
+  HlPriAttr cul_attrs  = { *cul_attr,  0 };
+
+  // TODO(bfredl, vigoux): line_attr should not take priority over decoration!
+  int num_signs = buf_get_signattrs(buf, lnum, sattrs, &num_attrs, &line_attrs, &cul_attrs);
+  decor_redraw_signs(buf, lnum - 1, &num_signs, sattrs, &num_attrs, &line_attrs, &cul_attrs);
+
+  *line_attr = line_attrs.attr_id;
+  *num_attr = num_attrs.attr_id;
+  *cul_attr = cul_attrs.attr_id;
+
+  return num_signs;
+}
+
+/// Return true if CursorLineNr highlight is to be used for the number column.
+///
+/// - 'cursorline' must be set
+/// - lnum must be the cursor line
+/// - 'cursorlineopt' has "number"
+/// - don't highlight filler lines (when in diff mode)
+/// - When line is wrapped and 'cursorlineopt' does not have "line", only highlight the line number
+///   itself on the first screenline of the wrapped line, otherwise highlight the number column of
+///   all screenlines of the wrapped line.
+static bool use_cursor_line_nr(win_T *wp, linenr_T lnum, int row, int startrow, int filler_lines)
+{
+  return wp->w_p_cul
+         && lnum == wp->w_cursor.lnum
+         && (wp->w_p_culopt_flags & CULOPT_NBR)
+         && (row == startrow + filler_lines
+             || (row > startrow + filler_lines
+                 && (wp->w_p_culopt_flags & CULOPT_LINE)));
+}
+
+static inline void get_line_number_str(win_T *wp, linenr_T lnum, char_u *buf, size_t buf_len)
+{
+  long num;
+  char *fmt = "%*ld ";
+
+  if (wp->w_p_nu && !wp->w_p_rnu) {
+    // 'number' + 'norelativenumber'
+    num = (long)lnum;
+  } else {
+    // 'relativenumber', don't use negative numbers
+    num = labs((long)get_cursor_rel_lnum(wp, lnum));
+    if (num == 0 && wp->w_p_nu && wp->w_p_rnu) {
+      // 'number' + 'relativenumber'
+      num = lnum;
+      fmt = "%-*ld ";
+    }
+  }
+
+  snprintf((char *)buf, buf_len, fmt, number_width(wp), num);
+}
+
+static int get_line_number_attr(win_T *wp, linenr_T lnum, int row, int startrow, int filler_lines)
+{
+  if (wp->w_p_rnu) {
+    if (lnum < wp->w_cursor.lnum) {
+      // Use LineNrAbove
+      return win_hl_attr(wp, HLF_LNA);
+    }
+    if (lnum > wp->w_cursor.lnum) {
+      // Use LineNrBelow
+      return win_hl_attr(wp, HLF_LNB);
+    }
+  }
+
+  if (use_cursor_line_nr(wp, lnum, row, startrow, filler_lines)) {
+    // TODO(vim): Can we use CursorLine instead of CursorLineNr
+    // when CursorLineNr isn't set?
+    return win_hl_attr(wp, HLF_CLN);
+  }
+
+  return win_hl_attr(wp, HLF_N);
+}
+
+static void apply_cursorline_highlight(win_T *wp, linenr_T lnum, int *line_attr, int *cul_attr,
+                                       int *line_attr_lowprio)
+{
+  *cul_attr = win_hl_attr(wp, HLF_CUL);
+  HlAttrs ae = syn_attr2entry(*cul_attr);
+  // We make a compromise here (#7383):
+  //  * low-priority CursorLine if fg is not set
+  //  * high-priority ("same as Vim" priority) CursorLine if fg is set
+  if (ae.rgb_fg_color == -1 && ae.cterm_fg_color == 0) {
+    *line_attr_lowprio = *cul_attr;
+  } else {
+    if (!(State & MODE_INSERT) && bt_quickfix(wp->w_buffer)
+        && qf_current_entry(wp) == lnum) {
+      *line_attr = hl_combine_attr(*cul_attr, *line_attr);
+    } else {
+      *line_attr = *cul_attr;
+    }
+  }
+}
+
+/// Display line "lnum" of window 'wp' on the screen.
+/// wp->w_virtcol needs to be valid.
+///
+/// @param lnum         line to display
+/// @param startrow     first row relative to window grid
+/// @param endrow       last grid row to be redrawn
+/// @param nochange     not updating for changed text
+/// @param number_only  only update the number column
+/// @param foldinfo     fold info for this line
+/// @param[in, out] providers  decoration providers active this line
+///                            items will be disables if they cause errors
+///                            or explicitly return `false`.
+///
+/// @return             the number of last row the line occupies.
+int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange, bool number_only,
+             foldinfo_T foldinfo, DecorProviders *providers, char **provider_err)
+{
+  int c = 0;                          // init for GCC
+  long vcol = 0;                      // virtual column (for tabs)
+  long vcol_sbr = -1;                 // virtual column after showbreak
+  long vcol_prev = -1;                // "vcol" of previous character
+  char_u *line;                  // current line
+  char_u *ptr;                   // current position in "line"
+  int row;                            // row in the window, excl w_winrow
+  ScreenGrid *grid = &wp->w_grid;     // grid specific to the window
+
+  char_u extra[57];                   // sign, line number and 'fdc' must
+                                      // fit in here
+  int n_extra = 0;                    // number of extra chars
+  char_u *p_extra = NULL;        // string of extra chars, plus NUL
+  char_u *p_extra_free = NULL;   // p_extra needs to be freed
+  int c_extra = NUL;                  // extra chars, all the same
+  int c_final = NUL;                  // final char, mandatory if set
+  int extra_attr = 0;                 // attributes when n_extra != 0
+  static char_u *at_end_str = (char_u *)"";  // used for p_extra when displaying
+                                             // curwin->w_p_lcs_chars.eol at
+                                             // end-of-line
+  int lcs_eol_one = wp->w_p_lcs_chars.eol;     // 'eol'  until it's been used
+  int lcs_prec_todo = wp->w_p_lcs_chars.prec;  // 'prec' until it's been used
+  bool has_fold = foldinfo.fi_level != 0 && foldinfo.fi_lines > 0;
+
+  // saved "extra" items for when draw_state becomes WL_LINE (again)
+  int saved_n_extra = 0;
+  char_u *saved_p_extra = NULL;
+  int saved_c_extra = 0;
+  int saved_c_final = 0;
+  int saved_char_attr = 0;
+
+  int n_attr = 0;                       // chars with special attr
+  int saved_attr2 = 0;                  // char_attr saved for n_attr
+  int n_attr3 = 0;                      // chars with overruling special attr
+  int saved_attr3 = 0;                  // char_attr saved for n_attr3
+
+  int n_skip = 0;                       // nr of chars to skip for 'nowrap'
+
+  int fromcol = -10;                    // start of inverting
+  int tocol = MAXCOL;                   // end of inverting
+  int fromcol_prev = -2;                // start of inverting after cursor
+  bool noinvcur = false;                // don't invert the cursor
+  bool lnum_in_visual_area = false;
+  pos_T pos;
+  long v;
+
+  int char_attr = 0;                    // attributes for next character
+  bool attr_pri = false;                // char_attr has priority
+  bool area_highlighting = false;       // Visual or incsearch highlighting in this line
+  int attr = 0;                         // attributes for area highlighting
+  int area_attr = 0;                    // attributes desired by highlighting
+  int search_attr = 0;                  // attributes desired by 'hlsearch'
+  int vcol_save_attr = 0;               // saved attr for 'cursorcolumn'
+  int syntax_attr = 0;                  // attributes desired by syntax
+  bool has_syntax = false;              // this buffer has syntax highl.
+  int save_did_emsg;
+  int eol_hl_off = 0;                   // 1 if highlighted char after EOL
+  bool draw_color_col = false;          // highlight colorcolumn
+  int *color_cols = NULL;               // pointer to according columns array
+  bool has_spell = false;               // this buffer has spell checking
+#define SPWORDLEN 150
+  char_u nextline[SPWORDLEN * 2];       // text with start of the next line
+  int nextlinecol = 0;                  // column where nextline[] starts
+  int nextline_idx = 0;                 // index in nextline[] where next line
+                                        // starts
+  int spell_attr = 0;                   // attributes desired by spelling
+  int word_end = 0;                     // last byte with same spell_attr
+  static linenr_T checked_lnum = 0;     // line number for "checked_col"
+  static int checked_col = 0;           // column in "checked_lnum" up to which
+                                        // there are no spell errors
+  static int cap_col = -1;              // column to check for Cap word
+  static linenr_T capcol_lnum = 0;      // line number where "cap_col"
+  int cur_checked_col = 0;              // checked column for current line
+  int extra_check = 0;                  // has syntax or linebreak
+  int multi_attr = 0;                   // attributes desired by multibyte
+  int mb_l = 1;                         // multi-byte byte length
+  int mb_c = 0;                         // decoded multi-byte character
+  bool mb_utf8 = false;                 // screen char is UTF-8 char
+  int u8cc[MAX_MCO];                    // composing UTF-8 chars
+  int filler_lines;                     // nr of filler lines to be drawn
+  int filler_todo;                      // nr of filler lines still to do + 1
+  hlf_T diff_hlf = (hlf_T)0;            // type of diff highlighting
+  int change_start = MAXCOL;            // first col of changed area
+  int change_end = -1;                  // last col of changed area
+  colnr_T trailcol = MAXCOL;            // start of trailing spaces
+  colnr_T leadcol = 0;                  // start of leading spaces
+  bool in_multispace = false;           // in multiple consecutive spaces
+  int multispace_pos = 0;               // position in lcs-multispace string
+  bool need_showbreak = false;          // overlong line, skip first x chars
+  int line_attr = 0;                    // attribute for the whole line
+  int line_attr_save;
+  int line_attr_lowprio = 0;            // low-priority attribute for the line
+  int line_attr_lowprio_save;
+  int prev_c = 0;                       // previous Arabic character
+  int prev_c1 = 0;                      // first composing char for prev_c
+
+  bool search_attr_from_match = false;  // if search_attr is from :match
+  bool has_decor = false;               // this buffer has decoration
+  int win_col_offset = 0;               // offset for window columns
+
+  char_u buf_fold[FOLD_TEXT_LEN];       // Hold value returned by get_foldtext
+
+  bool area_active = false;
+
+  int cul_attr = 0;                     // set when 'cursorline' active
+  // 'cursorlineopt' has "screenline" and cursor is in this line
+  bool cul_screenline = false;
+  // margin columns for the screen line, needed for when 'cursorlineopt'
+  // contains "screenline"
+  int left_curline_col = 0;
+  int right_curline_col = 0;
+
+  // draw_state: items that are drawn in sequence:
+#define WL_START        0               // nothing done yet
+#define WL_CMDLINE      (WL_START + 1)    // cmdline window column
+#define WL_FOLD         (WL_CMDLINE + 1)  // 'foldcolumn'
+#define WL_SIGN         (WL_FOLD + 1)     // column for signs
+#define WL_NR           (WL_SIGN + 1)     // line number
+#define WL_BRI          (WL_NR + 1)       // 'breakindent'
+#define WL_SBR          (WL_BRI + 1)      // 'showbreak' or 'diff'
+#define WL_LINE         (WL_SBR + 1)      // text in the line
+  int draw_state = WL_START;            // what to draw next
+
+  int syntax_flags    = 0;
+  int syntax_seqnr    = 0;
+  int prev_syntax_id  = 0;
+  int conceal_attr    = win_hl_attr(wp, HLF_CONCEAL);
+  bool is_concealing  = false;
+  int boguscols       = 0;              ///< nonexistent columns added to
+                                        ///< force wrapping
+  int vcol_off        = 0;              ///< offset for concealed characters
+  int did_wcol        = false;
+  int match_conc      = 0;              ///< cchar for match functions
+  int old_boguscols = 0;
+#define VCOL_HLC (vcol - vcol_off)
+#define FIX_FOR_BOGUSCOLS \
+  { \
+    n_extra += vcol_off; \
+    vcol -= vcol_off; \
+    vcol_off = 0; \
+    col -= boguscols; \
+    old_boguscols = boguscols; \
+    boguscols = 0; \
+  }
+
+  if (startrow > endrow) {              // past the end already!
+    return startrow;
+  }
+
+  row = startrow;
+
+  buf_T *buf = wp->w_buffer;
+  bool end_fill = (lnum == buf->b_ml.ml_line_count + 1);
+
+  if (!number_only) {
+    // To speed up the loop below, set extra_check when there is linebreak,
+    // trailing white space and/or syntax processing to be done.
+    extra_check = wp->w_p_lbr;
+    if (syntax_present(wp) && !wp->w_s->b_syn_error && !wp->w_s->b_syn_slow
+        && !has_fold && !end_fill) {
+      // Prepare for syntax highlighting in this line.  When there is an
+      // error, stop syntax highlighting.
+      save_did_emsg = did_emsg;
+      did_emsg = false;
+      syntax_start(wp, lnum);
+      if (did_emsg) {
+        wp->w_s->b_syn_error = true;
+      } else {
+        did_emsg = save_did_emsg;
+        if (!wp->w_s->b_syn_slow) {
+          has_syntax = true;
+          extra_check = true;
+        }
+      }
+    }
+
+    has_decor = decor_redraw_line(buf, lnum - 1, &decor_state);
+
+    providers_invoke_line(wp, providers, lnum - 1, &has_decor, provider_err);
+
+    if (*provider_err) {
+      provider_err_virt_text(lnum, *provider_err);
+      has_decor = true;
+      *provider_err = NULL;
+    }
+
+    if (has_decor) {
+      extra_check = true;
+    }
+
+    // Check for columns to display for 'colorcolumn'.
+    color_cols = wp->w_buffer->terminal ? NULL : wp->w_p_cc_cols;
+    if (color_cols != NULL) {
+      draw_color_col = advance_color_col((int)VCOL_HLC, &color_cols);
+    }
+
+    if (wp->w_p_spell
+        && !has_fold
+        && !end_fill
+        && *wp->w_s->b_p_spl != NUL
+        && !GA_EMPTY(&wp->w_s->b_langp)
+        && *(char **)(wp->w_s->b_langp.ga_data) != NULL) {
+      // Prepare for spell checking.
+      has_spell = true;
+      extra_check = true;
+
+      // Get the start of the next line, so that words that wrap to the next
+      // line are found too: "et<line-break>al.".
+      // Trick: skip a few chars for C/shell/Vim comments
+      nextline[SPWORDLEN] = NUL;
+      if (lnum < wp->w_buffer->b_ml.ml_line_count) {
+        line = ml_get_buf(wp->w_buffer, lnum + 1, false);
+        spell_cat_line(nextline + SPWORDLEN, line, SPWORDLEN);
+      }
+
+      // When a word wrapped from the previous line the start of the current
+      // line is valid.
+      if (lnum == checked_lnum) {
+        cur_checked_col = checked_col;
+      }
+      checked_lnum = 0;
+
+      // When there was a sentence end in the previous line may require a
+      // word starting with capital in this line.  In line 1 always check
+      // the first word.
+      if (lnum != capcol_lnum) {
+        cap_col = -1;
+      }
+      if (lnum == 1) {
+        cap_col = 0;
+      }
+      capcol_lnum = 0;
+    }
+
+    // handle Visual active in this window
+    if (VIsual_active && wp->w_buffer == curwin->w_buffer) {
+      pos_T *top, *bot;
+
+      if (ltoreq(curwin->w_cursor, VIsual)) {
+        // Visual is after curwin->w_cursor
+        top = &curwin->w_cursor;
+        bot = &VIsual;
+      } else {
+        // Visual is before curwin->w_cursor
+        top = &VIsual;
+        bot = &curwin->w_cursor;
+      }
+      lnum_in_visual_area = (lnum >= top->lnum && lnum <= bot->lnum);
+      if (VIsual_mode == Ctrl_V) {
+        // block mode
+        if (lnum_in_visual_area) {
+          fromcol = wp->w_old_cursor_fcol;
+          tocol = wp->w_old_cursor_lcol;
+        }
+      } else {
+        // non-block mode
+        if (lnum > top->lnum && lnum <= bot->lnum) {
+          fromcol = 0;
+        } else if (lnum == top->lnum) {
+          if (VIsual_mode == 'V') {       // linewise
+            fromcol = 0;
+          } else {
+            getvvcol(wp, top, (colnr_T *)&fromcol, NULL, NULL);
+            if (gchar_pos(top) == NUL) {
+              tocol = fromcol + 1;
+            }
+          }
+        }
+        if (VIsual_mode != 'V' && lnum == bot->lnum) {
+          if (*p_sel == 'e' && bot->col == 0
+              && bot->coladd == 0) {
+            fromcol = -10;
+            tocol = MAXCOL;
+          } else if (bot->col == MAXCOL) {
+            tocol = MAXCOL;
+          } else {
+            pos = *bot;
+            if (*p_sel == 'e') {
+              getvvcol(wp, &pos, (colnr_T *)&tocol, NULL, NULL);
+            } else {
+              getvvcol(wp, &pos, NULL, NULL, (colnr_T *)&tocol);
+              tocol++;
+            }
+          }
+        }
+      }
+
+      // Check if the char under the cursor should be inverted (highlighted).
+      if (!highlight_match && lnum == curwin->w_cursor.lnum && wp == curwin
+          && cursor_is_block_during_visual(*p_sel == 'e')) {
+        noinvcur = true;
+      }
+
+      // if inverting in this line set area_highlighting
+      if (fromcol >= 0) {
+        area_highlighting = true;
+        attr = win_hl_attr(wp, HLF_V);
+      }
+      // handle 'incsearch' and ":s///c" highlighting
+    } else if (highlight_match
+               && wp == curwin
+               && !has_fold
+               && lnum >= curwin->w_cursor.lnum
+               && lnum <= curwin->w_cursor.lnum + search_match_lines) {
+      if (lnum == curwin->w_cursor.lnum) {
+        getvcol(curwin, &(curwin->w_cursor),
+                (colnr_T *)&fromcol, NULL, NULL);
+      } else {
+        fromcol = 0;
+      }
+      if (lnum == curwin->w_cursor.lnum + search_match_lines) {
+        pos.lnum = lnum;
+        pos.col = search_match_endcol;
+        getvcol(curwin, &pos, (colnr_T *)&tocol, NULL, NULL);
+      }
+      // do at least one character; happens when past end of line
+      if (fromcol == tocol && search_match_endcol) {
+        tocol = fromcol + 1;
+      }
+      area_highlighting = true;
+      attr = win_hl_attr(wp, HLF_I);
+    }
+  }
+
+  int bg_attr = win_bg_attr(wp);
+
+  filler_lines = diff_check(wp, lnum);
+  if (filler_lines < 0) {
+    if (filler_lines == -1) {
+      if (diff_find_change(wp, lnum, &change_start, &change_end)) {
+        diff_hlf = HLF_ADD;             // added line
+      } else if (change_start == 0) {
+        diff_hlf = HLF_TXD;             // changed text
+      } else {
+        diff_hlf = HLF_CHD;             // changed line
+      }
+    } else {
+      diff_hlf = HLF_ADD;               // added line
+    }
+    filler_lines = 0;
+    area_highlighting = true;
+  }
+  VirtLines virt_lines = KV_INITIAL_VALUE;
+  int n_virt_lines = decor_virt_lines(wp, lnum, &virt_lines);
+  filler_lines += n_virt_lines;
+  if (lnum == wp->w_topline) {
+    filler_lines = wp->w_topfill;
+    n_virt_lines = MIN(n_virt_lines, filler_lines);
+  }
+  filler_todo = filler_lines;
+
+  // Cursor line highlighting for 'cursorline' in the current window.
+  if (lnum == wp->w_cursor.lnum) {
+    // Do not show the cursor line in the text when Visual mode is active,
+    // because it's not clear what is selected then.
+    if (wp->w_p_cul && !(wp == curwin && VIsual_active)
+        && wp->w_p_culopt_flags != CULOPT_NBR) {
+      cul_screenline = (wp->w_p_wrap
+                        && (wp->w_p_culopt_flags & CULOPT_SCRLINE));
+      if (!cul_screenline) {
+        apply_cursorline_highlight(wp, lnum, &line_attr, &cul_attr, &line_attr_lowprio);
+      } else {
+        margin_columns_win(wp, &left_curline_col, &right_curline_col);
+      }
+      area_highlighting = true;
+    }
+  }
+
+  SignTextAttrs sattrs[SIGN_SHOW_MAX];  // sign attributes for the sign column
+  int sign_num_attr = 0;                // sign attribute for the number column
+  int sign_cul_attr = 0;                // sign attribute for cursorline
+  CLEAR_FIELD(sattrs);
+  int num_signs = get_sign_attrs(buf, lnum, sattrs, &line_attr, &sign_num_attr, &sign_cul_attr);
+
+  // Highlight the current line in the quickfix window.
+  if (bt_quickfix(wp->w_buffer) && qf_current_entry(wp) == lnum) {
+    line_attr = win_hl_attr(wp, HLF_QFL);
+  }
+
+  if (line_attr_lowprio || line_attr) {
+    area_highlighting = true;
+  }
+
+  if (cul_screenline) {
+    line_attr_save = line_attr;
+    line_attr_lowprio_save = line_attr_lowprio;
+  }
+
+  line = end_fill ? (char_u *)"" : ml_get_buf(wp->w_buffer, lnum, false);
+  ptr = line;
+
+  if (has_spell && !number_only) {
+    // For checking first word with a capital skip white space.
+    if (cap_col == 0) {
+      cap_col = (int)getwhitecols(line);
+    }
+
+    // To be able to spell-check over line boundaries copy the end of the
+    // current line into nextline[].  Above the start of the next line was
+    // copied to nextline[SPWORDLEN].
+    if (nextline[SPWORDLEN] == NUL) {
+      // No next line or it is empty.
+      nextlinecol = MAXCOL;
+      nextline_idx = 0;
+    } else {
+      v = (long)STRLEN(line);
+      if (v < SPWORDLEN) {
+        // Short line, use it completely and append the start of the
+        // next line.
+        nextlinecol = 0;
+        memmove(nextline, line, (size_t)v);
+        STRMOVE(nextline + v, nextline + SPWORDLEN);
+        nextline_idx = (int)v + 1;
+      } else {
+        // Long line, use only the last SPWORDLEN bytes.
+        nextlinecol = (int)v - SPWORDLEN;
+        memmove(nextline, line + nextlinecol, SPWORDLEN);  // -V512
+        nextline_idx = SPWORDLEN + 1;
+      }
+    }
+  }
+
+  if (wp->w_p_list && !has_fold && !end_fill) {
+    if (wp->w_p_lcs_chars.space
+        || wp->w_p_lcs_chars.multispace != NULL
+        || wp->w_p_lcs_chars.leadmultispace != NULL
+        || wp->w_p_lcs_chars.trail
+        || wp->w_p_lcs_chars.lead
+        || wp->w_p_lcs_chars.nbsp) {
+      extra_check = true;
+    }
+    // find start of trailing whitespace
+    if (wp->w_p_lcs_chars.trail) {
+      trailcol = (colnr_T)STRLEN(ptr);
+      while (trailcol > (colnr_T)0 && ascii_iswhite(ptr[trailcol - 1])) {
+        trailcol--;
+      }
+      trailcol += (colnr_T)(ptr - line);
+    }
+    // find end of leading whitespace
+    if (wp->w_p_lcs_chars.lead || wp->w_p_lcs_chars.leadmultispace != NULL) {
+      leadcol = 0;
+      while (ascii_iswhite(ptr[leadcol])) {
+        leadcol++;
+      }
+      if (ptr[leadcol] == NUL) {
+        // in a line full of spaces all of them are treated as trailing
+        leadcol = (colnr_T)0;
+      } else {
+        // keep track of the first column not filled with spaces
+        leadcol += (colnr_T)(ptr - line) + 1;
+      }
+    }
+  }
+
+  // 'nowrap' or 'wrap' and a single line that doesn't fit: Advance to the
+  // first character to be displayed.
+  if (wp->w_p_wrap) {
+    v = wp->w_skipcol;
+  } else {
+    v = wp->w_leftcol;
+  }
+  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);
+    }
+
+    // When:
+    // - 'cuc' is set, or
+    // - 'colorcolumn' is set, or
+    // - 'virtualedit' is set, or
+    // - the visual mode is active,
+    // the end of the line may be before the start of the displayed part.
+    if (vcol < v && (wp->w_p_cuc
+                     || draw_color_col
+                     || virtual_active()
+                     || (VIsual_active && wp->w_buffer == curwin->w_buffer))) {
+      vcol = v;
+    }
+
+    // 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;
+      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) {
+        n_skip = (int)(v - vcol);
+      }
+    }
+
+    // Adjust for when the inverted text is before the screen,
+    // and when the start of the inverted text is before the screen.
+    if (tocol <= vcol) {
+      fromcol = 0;
+    } else if (fromcol >= 0 && fromcol < vcol) {