neovim

ex_cmds.c (161731B)

---

// ex_cmds.c: some functions for command line commands

#include <assert.h>
#include <ctype.h>
#include <float.h>
#include <inttypes.h>
#include <limits.h>
#include <math.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include "auto/config.h"
#include "klib/kvec.h"
#include "nvim/api/private/helpers.h"
#include "nvim/arglist.h"
#include "nvim/ascii_defs.h"
#include "nvim/autocmd.h"
#include "nvim/autocmd_defs.h"
#include "nvim/buffer.h"
#include "nvim/buffer_defs.h"
#include "nvim/buffer_updates.h"
#include "nvim/bufwrite.h"
#include "nvim/change.h"
#include "nvim/channel.h"
#include "nvim/charset.h"
#include "nvim/cmdexpand_defs.h"
#include "nvim/cmdhist.h"
#include "nvim/cursor.h"
#include "nvim/decoration.h"
#include "nvim/diff.h"
#include "nvim/digraph.h"
#include "nvim/drawscreen.h"
#include "nvim/edit.h"
#include "nvim/errors.h"
#include "nvim/eval/typval.h"
#include "nvim/eval/typval_defs.h"
#include "nvim/eval/vars.h"
#include "nvim/ex_cmds.h"
#include "nvim/ex_cmds2.h"
#include "nvim/ex_cmds_defs.h"
#include "nvim/ex_docmd.h"
#include "nvim/ex_eval.h"
#include "nvim/ex_getln.h"
#include "nvim/extmark.h"
#include "nvim/extmark_defs.h"
#include "nvim/fileio.h"
#include "nvim/fold.h"
#include "nvim/getchar.h"
#include "nvim/gettext_defs.h"
#include "nvim/globals.h"
#include "nvim/help.h"
#include "nvim/highlight_defs.h"
#include "nvim/highlight_group.h"
#include "nvim/indent.h"
#include "nvim/input.h"
#include "nvim/macros_defs.h"
#include "nvim/main.h"
#include "nvim/mark.h"
#include "nvim/mark_defs.h"
#include "nvim/mbyte.h"
#include "nvim/memline.h"
#include "nvim/memline_defs.h"
#include "nvim/memory.h"
#include "nvim/message.h"
#include "nvim/mouse.h"
#include "nvim/move.h"
#include "nvim/normal.h"
#include "nvim/ops.h"
#include "nvim/option.h"
#include "nvim/option_defs.h"
#include "nvim/option_vars.h"
#include "nvim/os/fs.h"
#include "nvim/os/fs_defs.h"
#include "nvim/os/input.h"
#include "nvim/os/os.h"
#include "nvim/os/os_defs.h"
#include "nvim/os/shell.h"
#include "nvim/os/time.h"
#include "nvim/path.h"
#include "nvim/plines.h"
#include "nvim/pos_defs.h"
#include "nvim/profile.h"
#include "nvim/quickfix.h"
#include "nvim/regexp.h"
#include "nvim/regexp_defs.h"
#include "nvim/search.h"
#include "nvim/spell.h"
#include "nvim/state_defs.h"
#include "nvim/strings.h"
#include "nvim/terminal.h"
#include "nvim/types_defs.h"
#include "nvim/ui.h"
#include "nvim/ui_defs.h"
#include "nvim/undo.h"
#include "nvim/vim_defs.h"
#include "nvim/window.h"

/// Case matching style to use for :substitute
typedef enum {
 kSubHonorOptions = 0,  ///< Honor the user's 'ignorecase'/'smartcase' options
 kSubIgnoreCase,        ///< Ignore case of the search
 kSubMatchCase,         ///< Match case of the search
} SubIgnoreType;

/// Flags kept between calls to :substitute.
typedef struct {
 bool do_all;          ///< do multiple substitutions per line
 bool do_ask;          ///< ask for confirmation
 bool do_count;        ///< count only
 bool do_error;        ///< if false, ignore errors
 bool do_print;        ///< print last line with subs
 bool do_list;         ///< list last line with subs
 bool do_number;       ///< list last line with line nr
 SubIgnoreType do_ic;  ///< ignore case flag
} subflags_T;

/// Partial result of a substitution during :substitute.
/// Numbers refer to the buffer _after_ substitution
typedef struct {
 lpos_T start;  // start of the match
 lpos_T end;    // end of the match
 linenr_T pre_match;  // where to begin showing lines before the match
} SubResult;

// Collected results of a substitution for showing them in
// the preview window
typedef struct {
 kvec_t(SubResult) subresults;
 linenr_T lines_needed;  // lines needed in the preview window
} PreviewLines;

#include "ex_cmds.c.generated.h"

static const char e_non_numeric_argument_to_z[]
 = N_("E144: Non-numeric argument to :z");

/// ":ascii" and "ga" implementation
void do_ascii(exarg_T *eap)
{
 char *data = get_cursor_pos_ptr();
 size_t len = (size_t)utfc_ptr2len(data);

 if (len == 0) {
   msg("NUL", 0);
   return;
 }

 bool need_clear = true;
 msg_sb_eol();
 msg_start();

 int c = utf_ptr2char(data);
 size_t off = 0;

 // TODO(bfredl): merge this with the main loop
 if (c < 0x80) {
   if (c == NL) {  // NUL is stored as NL.
     c = NUL;
   }
   const int cval = (c == CAR && get_fileformat(curbuf) == EOL_MAC
                     ? NL  // NL is stored as CR.
                     : c);
   char buf1[20];
   if (vim_isprintc(c) && (c < ' ' || c > '~')) {
     char buf3[7];
     transchar_nonprint(curbuf, buf3, c);
     vim_snprintf(buf1, sizeof(buf1), "  <%s>", buf3);
   } else {
     buf1[0] = NUL;
   }
   char buf2[20];
   buf2[0] = NUL;

   char *dig = get_digraph_for_char(cval);
   if (dig != NULL) {
     vim_snprintf(IObuff, sizeof(IObuff),
                  _("<%s>%s%s  %d,  Hex %02x,  Oct %03o, Digr %s"),
                  transchar(c), buf1, buf2, cval, cval, cval, dig);
   } else {
     vim_snprintf(IObuff, sizeof(IObuff),
                  _("<%s>%s%s  %d,  Hex %02x,  Octal %03o"),
                  transchar(c), buf1, buf2, cval, cval, cval);
   }

   msg_multiline(cstr_as_string(IObuff), 0, true, false, &need_clear);

   off += (size_t)utf_ptr2len(data);  // needed for overlong ascii?
 }

 // Repeat for combining characters, also handle multiby here.
 while (off < len) {
   c = utf_ptr2char(data + off);

   size_t iobuff_len = 0;
   // This assumes every multi-byte char is printable...
   if (off > 0) {
     IObuff[iobuff_len++] = ' ';
   }
   IObuff[iobuff_len++] = '<';
   if (utf_iscomposing_first(c)) {
     IObuff[iobuff_len++] = ' ';  // Draw composing char on top of a space.
   }
   iobuff_len += (size_t)utf_char2bytes(c, IObuff + iobuff_len);

   char *dig = get_digraph_for_char(c);
   if (dig != NULL) {
     vim_snprintf(IObuff + iobuff_len, sizeof(IObuff) - iobuff_len,
                  (c < 0x10000
                   ? _("> %d, Hex %04x, Oct %o, Digr %s")
                   : _("> %d, Hex %08x, Oct %o, Digr %s")),
                  c, c, c, dig);
   } else {
     vim_snprintf(IObuff + iobuff_len, sizeof(IObuff) - iobuff_len,
                  (c < 0x10000
                   ? _("> %d, Hex %04x, Octal %o")
                   : _("> %d, Hex %08x, Octal %o")),
                  c, c, c);
   }

   msg_multiline(cstr_as_string(IObuff), 0, true, false, &need_clear);

   off += (size_t)utf_ptr2len(data + off);  // needed for overlong ascii?
 }

 if (need_clear) {
   msg_clr_eos();
 }
 msg_end();
}

/// ":left", ":center" and ":right": align text.
void ex_align(exarg_T *eap)
{
 int indent = 0;
 int new_indent;

 if (curwin->w_p_rl) {
   // switch left and right aligning
   if (eap->cmdidx == CMD_right) {
     eap->cmdidx = CMD_left;
   } else if (eap->cmdidx == CMD_left) {
     eap->cmdidx = CMD_right;
   }
 }

 int width = atoi(eap->arg);
 pos_T save_curpos = curwin->w_cursor;
 if (eap->cmdidx == CMD_left) {    // width is used for new indent
   if (width >= 0) {
     indent = width;
   }
 } else {
   // if 'textwidth' set, use it
   // else if 'wrapmargin' set, use it
   // if invalid value, use 80
   if (width <= 0) {
     width = (int)curbuf->b_p_tw;
   }
   if (width == 0 && curbuf->b_p_wm > 0) {
     width = curwin->w_view_width - (int)curbuf->b_p_wm;
   }
   if (width <= 0) {
     width = 80;
   }
 }

 if (u_save((linenr_T)(eap->line1 - 1), (linenr_T)(eap->line2 + 1)) == FAIL) {
   return;
 }

 for (curwin->w_cursor.lnum = eap->line1;
      curwin->w_cursor.lnum <= eap->line2; curwin->w_cursor.lnum++) {
   if (eap->cmdidx == CMD_left) {              // left align
     new_indent = indent;
   } else {
     int has_tab = false;          // avoid uninit warnings
     int len = linelen(eap->cmdidx == CMD_right ? &has_tab : NULL) - get_indent();

     if (len <= 0) {                           // skip blank lines
       continue;
     }

     if (eap->cmdidx == CMD_center) {
       new_indent = (width - len) / 2;
     } else {
       new_indent = width - len;               // right align

       // Make sure that embedded TABs don't make the text go too far
       // to the right.
       if (has_tab) {
         while (new_indent > 0) {
           set_indent(new_indent, 0);
           if (linelen(NULL) <= width) {
             // Now try to move the line as much as possible to
             // the right.  Stop when it moves too far.
             do {
               set_indent(++new_indent, 0);
             } while (linelen(NULL) <= width);
             new_indent--;
             break;
           }
           new_indent--;
         }
       }
     }
   }
   new_indent = MAX(new_indent, 0);
   set_indent(new_indent, 0);                    // set indent
 }
 changed_lines(curbuf, eap->line1, 0, eap->line2 + 1, 0, true);
 curwin->w_cursor = save_curpos;
 beginline(BL_WHITE | BL_FIX);
}

/// @return  the length of the current line, excluding trailing white space.
static int linelen(int *has_tab)
{
 char *last;

 // Get the line.  If it's empty bail out early (could be the empty string
 // for an unloaded buffer).
 char *line = get_cursor_line_ptr();
 if (*line == NUL) {
   return 0;
 }
 // find the first non-blank character
 char *first = skipwhite(line);

 // find the character after the last non-blank character
 for (last = first + strlen(first);
      last > first && ascii_iswhite(last[-1]); last--) {}
 char save = *last;
 *last = NUL;
 int len = linetabsize_str(line);  // Get line length.
 if (has_tab != NULL) {        // Check for embedded TAB.
   *has_tab = vim_strchr(first, TAB) != NULL;
 }
 *last = save;

 return len;
}

// Buffer for two lines used during sorting.  They are allocated to
// contain the longest line being sorted.
static char *sortbuf1;
static char *sortbuf2;

static bool sort_lc;      ///< sort using locale
static bool sort_ic;      ///< ignore case
static bool sort_nr;      ///< sort on number
static bool sort_rx;      ///< sort on regex instead of skipping it
static bool sort_flt;     ///< sort on floating number

static bool sort_abort;   ///< flag to indicate if sorting has been interrupted

/// Struct to store info to be sorted.
typedef struct {
 linenr_T lnum;          ///< line number
 union {
   struct {
     varnumber_T start_col_nr;  ///< starting column number
     varnumber_T end_col_nr;    ///< ending column number
   } line;
   struct {
     varnumber_T value;         ///< value if sorting by integer
     bool is_number;            ///< true when line contains a number
   } num;
   float_T value_flt;    ///< value if sorting by float
 } st_u;
} sorti_T;

static int string_compare(const void *s1, const void *s2) FUNC_ATTR_NONNULL_ALL
{
 if (sort_lc) {
   return strcoll((const char *)s1, (const char *)s2);
 }
 return sort_ic ? STRICMP(s1, s2) : strcmp(s1, s2);
}

static int sort_compare(const void *s1, const void *s2)
{
 sorti_T l1 = *(sorti_T *)s1;
 sorti_T l2 = *(sorti_T *)s2;
 int result = 0;

 // If the user interrupts, there's no way to stop qsort() immediately, but
 // if we return 0 every time, qsort will assume it's done sorting and
 // exit.
 if (sort_abort) {
   return 0;
 }
 fast_breakcheck();
 if (got_int) {
   sort_abort = true;
 }

 // When sorting numbers "start_col_nr" is the number, not the column
 // number.
 if (sort_nr) {
   if (l1.st_u.num.is_number != l2.st_u.num.is_number) {
     result = l1.st_u.num.is_number > l2.st_u.num.is_number ? 1 : -1;
   } else {
     result = l1.st_u.num.value == l2.st_u.num.value
              ? 0
              : l1.st_u.num.value > l2.st_u.num.value ? 1 : -1;
   }
 } else if (sort_flt) {
   result = l1.st_u.value_flt == l2.st_u.value_flt
            ? 0
            : l1.st_u.value_flt > l2.st_u.value_flt ? 1 : -1;
 } else {
   // We need to copy one line into "sortbuf1", because there is no
   // guarantee that the first pointer becomes invalid when obtaining the
   // second one.
   memcpy(sortbuf1, ml_get(l1.lnum) + l1.st_u.line.start_col_nr,
          (size_t)(l1.st_u.line.end_col_nr - l1.st_u.line.start_col_nr + 1));
   sortbuf1[l1.st_u.line.end_col_nr - l1.st_u.line.start_col_nr] = NUL;
   memcpy(sortbuf2, ml_get(l2.lnum) + l2.st_u.line.start_col_nr,
          (size_t)(l2.st_u.line.end_col_nr - l2.st_u.line.start_col_nr + 1));
   sortbuf2[l2.st_u.line.end_col_nr - l2.st_u.line.start_col_nr] = NUL;

   result = string_compare(sortbuf1, sortbuf2);
 }

 // If two lines have the same value, preserve the original line order.
 if (result == 0) {
   return l1.lnum - l2.lnum;
 }
 return result;
}

/// ":sort".
void ex_sort(exarg_T *eap)
{
 regmatch_T regmatch;
 int maxlen = 0;
 size_t count = (size_t)(eap->line2 - eap->line1) + 1;
 size_t i;
 bool unique = false;
 int sort_what = 0;

 // Sorting one line is really quick!
 if (count <= 1) {
   return;
 }

 if (u_save((linenr_T)(eap->line1 - 1), (linenr_T)(eap->line2 + 1)) == FAIL) {
   return;
 }
 sortbuf1 = NULL;
 sortbuf2 = NULL;
 regmatch.regprog = NULL;
 sorti_T *nrs = xmalloc(count * sizeof(sorti_T));

 sort_abort = sort_ic = sort_lc = sort_rx = sort_nr = sort_flt = false;
 size_t format_found = 0;
 bool change_occurred = false;   // Buffer contents changed.

 for (char *p = eap->arg; *p != NUL; p++) {
   if (ascii_iswhite(*p)) {
     // Skip
   } else if (*p == 'i') {
     sort_ic = true;
   } else if (*p == 'l') {
     sort_lc = true;
   } else if (*p == 'r') {
     sort_rx = true;
   } else if (*p == 'n') {
     sort_nr = true;
     format_found++;
   } else if (*p == 'f') {
     sort_flt = true;
     format_found++;
   } else if (*p == 'b') {
     sort_what = STR2NR_BIN + STR2NR_FORCE;
     format_found++;
   } else if (*p == 'o') {
     sort_what = STR2NR_OCT + STR2NR_FORCE;
     format_found++;
   } else if (*p == 'x') {
     sort_what = STR2NR_HEX + STR2NR_FORCE;
     format_found++;
   } else if (*p == 'u') {
     unique = true;
   } else if (*p == '"') {  // comment start
     break;
   } else if (check_nextcmd(p) != NULL) {
     eap->nextcmd = check_nextcmd(p);
     break;
   } else if (!ASCII_ISALPHA(*p) && regmatch.regprog == NULL) {
     char *s = skip_regexp_err(p + 1, *p, true);
     if (s == NULL) {
       goto sortend;
     }
     *s = NUL;
     // Use last search pattern if sort pattern is empty.
     if (s == p + 1) {
       if (last_search_pat() == NULL) {
         emsg(_(e_noprevre));
         goto sortend;
       }
       regmatch.regprog = vim_regcomp(last_search_pat(), RE_MAGIC);
     } else {
       regmatch.regprog = vim_regcomp(p + 1, RE_MAGIC);
     }
     if (regmatch.regprog == NULL) {
       goto sortend;
     }
     p = s;                    // continue after the regexp
     regmatch.rm_ic = p_ic;
   } else {
     semsg(_(e_invarg2), p);
     goto sortend;
   }
 }

 // Can only have one of 'n', 'b', 'o' and 'x'.
 if (format_found > 1) {
   emsg(_(e_invarg));
   goto sortend;
 }

 // From here on "sort_nr" is used as a flag for any integer number
 // sorting.
 sort_nr |= sort_what;

 // Make an array with all line numbers.  This avoids having to copy all
 // the lines into allocated memory.
 // When sorting on strings "start_col_nr" is the offset in the line, for
 // numbers sorting it's the number to sort on.  This means the pattern
 // matching and number conversion only has to be done once per line.
 // Also get the longest line length for allocating "sortbuf".
 for (linenr_T lnum = eap->line1; lnum <= eap->line2; lnum++) {
   char *s = ml_get(lnum);
   int len = ml_get_len(lnum);
   maxlen = MAX(maxlen, len);

   colnr_T start_col = 0;
   colnr_T end_col = len;
   if (regmatch.regprog != NULL && vim_regexec(&regmatch, s, 0)) {
     if (sort_rx) {
       start_col = (colnr_T)(regmatch.startp[0] - s);
       end_col = (colnr_T)(regmatch.endp[0] - s);
     } else {
       start_col = (colnr_T)(regmatch.endp[0] - s);
     }
   } else if (regmatch.regprog != NULL) {
     end_col = 0;
   }

   if (sort_nr || sort_flt) {
     // Make sure vim_str2nr() doesn't read any digits past the end
     // of the match, by temporarily terminating the string there
     char *s2 = s + end_col;
     char c = *s2;  // temporary character storage
     *s2 = NUL;
     // Sorting on number: Store the number itself.
     char *p = s + start_col;
     if (sort_nr) {
       if (sort_what & STR2NR_HEX) {
         s = skiptohex(p);
       } else if (sort_what & STR2NR_BIN) {
         s = (char *)skiptobin(p);
       } else {
         s = skiptodigit(p);
       }
       if (s > p && s[-1] == '-') {
         s--;  // include preceding negative sign
       }
       if (*s == NUL) {
         // line without number should sort before any number
         nrs[lnum - eap->line1].st_u.num.is_number = false;
         nrs[lnum - eap->line1].st_u.num.value = 0;
       } else {
         nrs[lnum - eap->line1].st_u.num.is_number = true;
         vim_str2nr(s, NULL, NULL, sort_what,
                    &nrs[lnum - eap->line1].st_u.num.value, NULL, 0, false, NULL);
       }
     } else {
       s = skipwhite(p);
       if (*s == '+') {
         s = skipwhite(s + 1);
       }

       if (*s == NUL) {
         // empty line should sort before any number
         nrs[lnum - eap->line1].st_u.value_flt = -DBL_MAX;
       } else {
         nrs[lnum - eap->line1].st_u.value_flt = strtod(s, NULL);
       }
     }
     *s2 = c;
   } else {
     // Store the column to sort at.
     nrs[lnum - eap->line1].st_u.line.start_col_nr = start_col;
     nrs[lnum - eap->line1].st_u.line.end_col_nr = end_col;
   }

   nrs[lnum - eap->line1].lnum = lnum;

   if (regmatch.regprog != NULL) {
     fast_breakcheck();
   }
   if (got_int) {
     goto sortend;
   }
 }

 // Allocate a buffer that can hold the longest line.
 sortbuf1 = xmalloc((size_t)maxlen + 1);
 sortbuf2 = xmalloc((size_t)maxlen + 1);

 // Sort the array of line numbers.  Note: can't be interrupted!
 qsort((void *)nrs, count, sizeof(sorti_T), sort_compare);

 if (sort_abort) {
   goto sortend;
 }

 bcount_t old_count = 0;
 bcount_t new_count = 0;

 // Insert the lines in the sorted order below the last one.
 linenr_T lnum = eap->line2;
 for (i = 0; i < count; i++) {
   const linenr_T get_lnum = nrs[eap->forceit ? count - i - 1 : i].lnum;

   // If the original line number of the line being placed is not the same
   // as "lnum" (accounting for offset), we know that the buffer changed.
   if (get_lnum + ((linenr_T)count - 1) != lnum) {
     change_occurred = true;
   }

   char *s = ml_get(get_lnum);
   colnr_T bytelen = ml_get_len(get_lnum) + 1;  // include EOL in bytelen
   old_count += bytelen;
   if (!unique || i == 0 || string_compare(s, sortbuf1) != 0) {
     // Copy the line into a buffer, it may become invalid in
     // ml_append(). And it's needed for "unique".
     STRCPY(sortbuf1, s);
     if (ml_append(lnum++, sortbuf1, 0, false) == FAIL) {
       break;
     }
     new_count += bytelen;
   }
   fast_breakcheck();
   if (got_int) {
     goto sortend;
   }
 }

 // delete the original lines if appending worked
 if (i == count) {
   for (i = 0; i < count; i++) {
     ml_delete(eap->line1);
   }
 } else {
   count = 0;
 }

 // Adjust marks for deleted (or added) lines and prepare for displaying.
 linenr_T deleted = (linenr_T)count - (lnum - eap->line2);
 if (deleted > 0) {
   mark_adjust(eap->line2 - deleted, eap->line2, MAXLNUM, -deleted, kExtmarkNOOP);
   msgmore(-deleted);
 } else if (deleted < 0) {
   mark_adjust(eap->line2, MAXLNUM, -deleted, 0, kExtmarkNOOP);
 }

 if (change_occurred || deleted != 0) {
   extmark_splice(curbuf, eap->line1 - 1, 0,
                  (int)count, 0, old_count,
                  lnum - eap->line2, 0, new_count, kExtmarkUndo);
   changed_lines(curbuf, eap->line1, 0, eap->line2 + 1, -deleted, true);
 }

 curwin->w_cursor.lnum = eap->line1;
 beginline(BL_WHITE | BL_FIX);

sortend:
 xfree(nrs);
 xfree(sortbuf1);
 xfree(sortbuf2);
 vim_regfree(regmatch.regprog);
 if (got_int) {
   emsg(_(e_interr));
 }
}

/// ":uniq".
void ex_uniq(exarg_T *eap)
{
 regmatch_T regmatch;
 int maxlen = 0;
 linenr_T count = eap->line2 - eap->line1 + 1;
 bool keep_only_unique = false;
 bool keep_only_not_unique = eap->forceit;
 linenr_T deleted = 0;

 // Uniq one line is really quick!
 if (count <= 1) {
   return;
 }

 if (u_save((linenr_T)(eap->line1 - 1), (linenr_T)(eap->line2 + 1)) == FAIL) {
   return;
 }
 sortbuf1 = NULL;
 regmatch.regprog = NULL;

 sort_abort = sort_ic = sort_lc = sort_rx = sort_nr = sort_flt = false;
 bool change_occurred = false;    // Buffer contents changed.

 for (char *p = eap->arg; *p != NUL; p++) {
   if (ascii_iswhite(*p)) {
     // Skip
   } else if (*p == 'i') {
     sort_ic = true;
   } else if (*p == 'l') {
     sort_lc = true;
   } else if (*p == 'r') {
     sort_rx = true;
   } else if (*p == 'u') {
     // 'u' is only valid when '!' is not given.
     if (!keep_only_not_unique) {
       keep_only_unique = true;
     }
   } else if (*p == '"') {  // comment start
     break;
   } else if (eap->nextcmd == NULL && check_nextcmd(p) != NULL) {
     eap->nextcmd = check_nextcmd(p);
     break;
   } else if (!ASCII_ISALPHA(*p) && regmatch.regprog == NULL) {
     char *s = skip_regexp_err(p + 1, *p, true);
     if (s == NULL) {
       goto uniqend;
     }
     *s = NUL;
     // Use last search pattern if uniq pattern is empty.
     if (s == p + 1) {
       if (last_search_pat() == NULL) {
         emsg(_(e_noprevre));
         goto uniqend;
       }
       regmatch.regprog = vim_regcomp(last_search_pat(), RE_MAGIC);
     } else {
       regmatch.regprog = vim_regcomp(p + 1, RE_MAGIC);
     }
     if (regmatch.regprog == NULL) {
       goto uniqend;
     }
     p = s;              // continue after the regexp
     regmatch.rm_ic = p_ic;
   } else {
     semsg(_(e_invarg2), p);
     goto uniqend;
   }
 }

 // Find the length of the longest line.
 for (linenr_T lnum = eap->line1; lnum <= eap->line2; lnum++) {
   int len = ml_get_len(lnum);
   if (maxlen < len) {
     maxlen = len;
   }

   if (got_int) {
     goto uniqend;
   }
 }

 // Allocate a buffer that can hold the longest line.
 sortbuf1 = xmalloc((size_t)maxlen + 1);

 // Delete lines according to options.
 bool match_continue = false;
 bool next_is_unmatch = false;
 linenr_T done_lnum = eap->line1 - 1;
 linenr_T delete_lnum = 0;
 for (linenr_T i = 0; i < count; i++) {
   linenr_T get_lnum = eap->line1 + i;

   char *s = ml_get(get_lnum);
   int len = ml_get_len(get_lnum);

   colnr_T start_col = 0;
   colnr_T end_col = len;
   if (regmatch.regprog != NULL && vim_regexec(&regmatch, s, 0)) {
     if (sort_rx) {
       start_col = (colnr_T)(regmatch.startp[0] - s);
       end_col = (colnr_T)(regmatch.endp[0] - s);
     } else {
       start_col = (colnr_T)(regmatch.endp[0] - s);
     }
   } else if (regmatch.regprog != NULL) {
     end_col = 0;
   }
   char save_c = NUL;  // temporary character storage
   if (end_col > 0) {
     save_c = s[end_col];
     s[end_col] = NUL;
   }

   bool is_match = i > 0 ? !string_compare(&s[start_col], sortbuf1) : false;
   delete_lnum = 0;
   if (next_is_unmatch) {
     is_match = false;
     next_is_unmatch = false;
   }

   if (!keep_only_unique && !keep_only_not_unique) {
     if (is_match) {
       delete_lnum = get_lnum;
     } else {
       STRCPY(sortbuf1, &s[start_col]);
     }
   } else if (keep_only_not_unique) {
     if (is_match) {
       done_lnum = get_lnum - 1;
       delete_lnum = get_lnum;
       match_continue = true;
     } else {
       if (i > 0 && !match_continue && get_lnum - 1 > done_lnum) {
         delete_lnum = get_lnum - 1;
         next_is_unmatch = true;
       } else if (i >= count - 1) {
         delete_lnum = get_lnum;
       }
       match_continue = false;
       STRCPY(sortbuf1, &s[start_col]);
     }
   } else {  // keep_only_unique
     if (is_match) {
       if (!match_continue) {
         delete_lnum = get_lnum - 1;
       } else {
         delete_lnum = get_lnum;
       }
       match_continue = true;
     } else {
       if (i == 0 && match_continue) {
         delete_lnum = get_lnum;
       }
       match_continue = false;
       STRCPY(sortbuf1, &s[start_col]);
     }
   }

   if (end_col > 0) {
     s[end_col] = save_c;
   }

   if (delete_lnum > 0) {
     ml_delete(delete_lnum);
     i -= get_lnum - delete_lnum + 1;
     count--;
     deleted++;
     change_occurred = true;
   }

   fast_breakcheck();
   if (got_int) {
     goto uniqend;
   }
 }

 // Adjust marks for deleted lines and prepare for displaying.
 mark_adjust(eap->line2 - deleted, eap->line2, MAXLNUM, -deleted,
             change_occurred ? kExtmarkUndo : kExtmarkNOOP);
 msgmore(-deleted);

 if (change_occurred) {
   changed_lines(curbuf, eap->line1, 0, eap->line2 + 1, -deleted, true);
 }

 curwin->w_cursor.lnum = eap->line1;
 beginline(BL_WHITE | BL_FIX);

uniqend:
 xfree(sortbuf1);
 vim_regfree(regmatch.regprog);
 if (got_int) {
   emsg(_(e_interr));
 }
}

/// :move command - move lines line1-line2 to line dest
///
/// @return  FAIL for failure, OK otherwise
int do_move(linenr_T line1, linenr_T line2, linenr_T dest)
{
 if (dest >= line1 && dest < line2) {
   emsg(_("E134: Cannot move a range of lines into itself"));
   return FAIL;
 }

 // Do nothing if we are not actually moving any lines.  This will prevent
 // the 'modified' flag from being set without cause.
 if (dest == line1 - 1 || dest == line2) {
   // Move the cursor as if lines were moved (see below) to be backwards
   // compatible.
   curwin->w_cursor.lnum = dest >= line1
                           ? dest
                           : dest + (line2 - line1) + 1;
   return OK;
 }

 bcount_t start_byte = ml_find_line_or_offset(curbuf, line1, NULL, true);
 bcount_t end_byte = ml_find_line_or_offset(curbuf, line2 + 1, NULL, true);
 bcount_t extent_byte = end_byte - start_byte;
 bcount_t dest_byte = ml_find_line_or_offset(curbuf, dest + 1, NULL, true);

 linenr_T num_lines = line2 - line1 + 1;  // Num lines moved

 // First we copy the old text to its new location -- webb
 // Also copy the flag that ":global" command uses.
 if (u_save(dest, dest + 1) == FAIL) {
   return FAIL;
 }

 linenr_T l;
 linenr_T extra;      // Num lines added before line1
 for (extra = 0, l = line1; l <= line2; l++) {
   char *str = xstrnsave(ml_get(l + extra), (size_t)ml_get_len(l + extra));
   ml_append(dest + l - line1, str, 0, false);
   xfree(str);
   if (dest < line1) {
     extra++;
   }
 }

 // Now we must be careful adjusting our marks so that we don't overlap our
 // mark_adjust() calls.
 //
 // We adjust the marks within the old text so that they refer to the
 // last lines of the file (temporarily), because we know no other marks
 // will be set there since these line numbers did not exist until we added
 // our new lines.
 //
 // Then we adjust the marks on lines between the old and new text positions
 // (either forwards or backwards).
 //
 // And Finally we adjust the marks we put at the end of the file back to
 // their final destination at the new text position -- webb
 linenr_T last_line = curbuf->b_ml.ml_line_count;  // Last line in file after adding new text
 mark_adjust_nofold(line1, line2, last_line - line2, 0, kExtmarkNOOP);

 disable_fold_update++;
 changed_lines(curbuf, last_line - num_lines + 1, 0, last_line + 1, num_lines, false);
 disable_fold_update--;

 int line_off = 0;
 bcount_t byte_off = 0;
 if (dest >= line2) {
   mark_adjust_nofold(line2 + 1, dest, -num_lines, 0, kExtmarkNOOP);
   FOR_ALL_TAB_WINDOWS(tab, win) {
     if (win->w_buffer == curbuf) {
       foldMoveRange(win, &win->w_folds, line1, line2, dest);
     }
   }
   if ((cmdmod.cmod_flags & CMOD_LOCKMARKS) == 0) {
     curbuf->b_op_start.lnum = dest - num_lines + 1;
     curbuf->b_op_end.lnum = dest;
   }
   line_off = -num_lines;
   byte_off = -extent_byte;
 } else {
   mark_adjust_nofold(dest + 1, line1 - 1, num_lines, 0, kExtmarkNOOP);
   FOR_ALL_TAB_WINDOWS(tab, win) {
     if (win->w_buffer == curbuf) {
       foldMoveRange(win, &win->w_folds, dest + 1, line1 - 1, line2);
     }
   }
   if ((cmdmod.cmod_flags & CMOD_LOCKMARKS) == 0) {
     curbuf->b_op_start.lnum = dest + 1;
     curbuf->b_op_end.lnum = dest + num_lines;
   }
 }
 if ((cmdmod.cmod_flags & CMOD_LOCKMARKS) == 0) {
   curbuf->b_op_start.col = curbuf->b_op_end.col = 0;
 }
 mark_adjust_nofold(last_line - num_lines + 1, last_line,
                    -(last_line - dest - extra), 0, kExtmarkNOOP);

 disable_fold_update++;
 changed_lines(curbuf, last_line - num_lines + 1, 0, last_line + 1, -extra, false);
 disable_fold_update--;

 // send update regarding the new lines that were added
 buf_updates_send_changes(curbuf, dest + 1, num_lines, 0);

 // Now we delete the original text -- webb
 if (u_save(line1 + extra - 1, line2 + extra + 1) == FAIL) {
   return FAIL;
 }

 for (l = line1; l <= line2; l++) {
   ml_delete_flags(line1 + extra, ML_DEL_MESSAGE);
 }
 if (!global_busy && num_lines > p_report) {
   smsg(0, NGETTEXT("%" PRId64 " line moved",
                    "%" PRId64 " lines moved", num_lines),
        (int64_t)num_lines);
 }

 extmark_move_region(curbuf, line1 - 1, 0, start_byte,
                     line2 - line1 + 1, 0, extent_byte,
                     dest + line_off, 0, dest_byte + byte_off,
                     kExtmarkUndo);

 // Leave the cursor on the last of the moved lines.
 if (dest >= line1) {
   curwin->w_cursor.lnum = dest;
 } else {
   curwin->w_cursor.lnum = dest + (line2 - line1) + 1;
 }

 if (line1 < dest) {
   dest += num_lines + 1;
   last_line = curbuf->b_ml.ml_line_count;
   dest = MIN(dest, last_line + 1);
   changed_lines(curbuf, line1, 0, dest, 0, false);
 } else {
   changed_lines(curbuf, dest + 1, 0, line1 + num_lines, 0, false);
 }

 // send nvim_buf_lines_event regarding lines that were deleted
 buf_updates_send_changes(curbuf, line1 + extra, 0, num_lines);

 return OK;
}

/// ":copy"
void ex_copy(linenr_T line1, linenr_T line2, linenr_T n)
{
 linenr_T count = line2 - line1 + 1;
 if ((cmdmod.cmod_flags & CMOD_LOCKMARKS) == 0) {
   curbuf->b_op_start.lnum = n + 1;
   curbuf->b_op_end.lnum = n + count;
   curbuf->b_op_start.col = curbuf->b_op_end.col = 0;
 }

 // there are three situations:
 // 1. destination is above line1
 // 2. destination is between line1 and line2
 // 3. destination is below line2
 //
 // n = destination (when starting)
 // curwin->w_cursor.lnum = destination (while copying)
 // line1 = start of source (while copying)
 // line2 = end of source (while copying)
 if (u_save(n, n + 1) == FAIL) {
   return;
 }

 curwin->w_cursor.lnum = n;
 while (line1 <= line2) {
   // need to make a copy because the line will be unlocked within ml_append()
   char *p = xstrnsave(ml_get(line1), (size_t)ml_get_len(line1));
   ml_append(curwin->w_cursor.lnum, p, 0, false);
   xfree(p);

   // situation 2: skip already copied lines
   if (line1 == n) {
     line1 = curwin->w_cursor.lnum;
   }
   line1++;
   if (curwin->w_cursor.lnum < line1) {
     line1++;
   }
   if (curwin->w_cursor.lnum < line2) {
     line2++;
   }
   curwin->w_cursor.lnum++;
 }

 appended_lines_mark(n, count);
 if (VIsual_active) {
   check_pos(curbuf, &VIsual);
 }

 msgmore(count);
}

static char *prevcmd = NULL;        // the previous command

#if defined(EXITFREE)
void free_prev_shellcmd(void)
{
 xfree(prevcmd);
}

#endif

/// Check that "prevcmd" is not NULL.  If it is NULL then give an error message
/// and return false.
static int prevcmd_is_set(void)
{
 if (prevcmd == NULL) {
   emsg(_(e_noprev));
   return false;
 }
 return true;
}

/// Handle the ":!cmd" command.  Also for ":r !cmd" and ":w !cmd"
/// Bangs in the argument are replaced with the previously entered command.
/// Remember the argument.
void do_bang(int addr_count, exarg_T *eap, bool forceit, bool do_in, bool do_out)
 FUNC_ATTR_NONNULL_ALL
{
 char *arg = eap->arg;             // command
 linenr_T line1 = eap->line1;        // start of range
 linenr_T line2 = eap->line2;        // end of range
 char *newcmd = NULL;              // the new command
 bool free_newcmd = false;           // need to free() newcmd
 int scroll_save = msg_scroll;

 // Disallow shell commands in secure mode
 if (check_secure()) {
   return;
 }

 if (addr_count == 0) {                // :!
   msg_scroll = false;             // don't scroll here
   autowrite_all();
   msg_scroll = scroll_save;
 }

 // Try to find an embedded bang, like in ":!<cmd> ! [args]"
 // ":!!" is indicated by the 'forceit' variable.
 bool ins_prevcmd = forceit;

 // Skip leading white space to avoid a strange error with some shells.
 char *trailarg = skipwhite(arg);
 do {
   size_t len = strlen(trailarg) + 1;
   if (newcmd != NULL) {
     len += strlen(newcmd);
   }
   if (ins_prevcmd) {
     if (!prevcmd_is_set()) {
       xfree(newcmd);
       return;
     }
     len += strlen(prevcmd);
   }
   char *t = xmalloc(len);
   *t = NUL;
   if (newcmd != NULL) {
     strcat(t, newcmd);
   }
   if (ins_prevcmd) {
     strcat(t, prevcmd);
   }
   char *p = t + strlen(t);
   strcat(t, trailarg);
   xfree(newcmd);
   newcmd = t;

   // Scan the rest of the argument for '!', which is replaced by the
   // previous command.  "\!" is replaced by "!" (this is vi compatible).
   trailarg = NULL;
   while (*p) {
     if (*p == '!') {
       if (p > newcmd && p[-1] == '\\') {
         STRMOVE(p - 1, p);
       } else {
         trailarg = p;
         *trailarg++ = NUL;
         ins_prevcmd = true;
         break;
       }
     }
     p++;
   }
 } while (trailarg != NULL);

 // Only set "prevcmd" if there is a command to run, otherwise keep te one
 // we have.
 if (strlen(newcmd) > 0) {
   xfree(prevcmd);
   prevcmd = newcmd;
 } else {
   free_newcmd = true;
 }

 if (bangredo) {  // put cmd in redo buffer for ! command
   if (!prevcmd_is_set()) {
     goto theend;
   }

   // If % or # appears in the command, it must have been escaped.
   // Reescape them, so that redoing them does not substitute them by the
   // buffername.
   char *cmd = vim_strsave_escaped(prevcmd, "%#");

   AppendToRedobuffLit(cmd, -1);
   xfree(cmd);
   AppendToRedobuff("\n");
   bangredo = false;
 }
 // Add quotes around the command, for shells that need them.
 if (*p_shq != NUL) {
   if (free_newcmd) {
     xfree(newcmd);
   }
   newcmd = xmalloc(strlen(prevcmd) + 2 * strlen(p_shq) + 1);
   STRCPY(newcmd, p_shq);
   strcat(newcmd, prevcmd);
   strcat(newcmd, p_shq);
   free_newcmd = true;
 }
 if (addr_count == 0) {                // :!
   // echo the command
   msg_start();
   msg_ext_set_kind("shell_cmd");
   msg_putchar(':');
   msg_putchar('!');
   msg_outtrans(newcmd, 0, false);
   msg_clr_eos();
   ui_cursor_goto(msg_row, msg_col);

   do_shell(newcmd, 0);
 } else {                            // :range!
   // Careful: This may recursively call do_bang() again! (because of
   // autocommands)
   do_filter(line1, line2, eap, newcmd, do_in, do_out);
   apply_autocmds(EVENT_SHELLFILTERPOST, NULL, NULL, false, curbuf);
 }

theend:
 if (free_newcmd) {
   xfree(newcmd);
 }
}

/// do_filter: filter lines through a command given by the user
///
/// We mostly use temp files and the call_shell() routine here. This would
/// normally be done using pipes on a Unix system, but this is more portable
/// to non-Unix systems. The call_shell() routine needs to be able
/// to deal with redirection somehow, and should handle things like looking
/// at the PATH env. variable, and adding reasonable extensions to the
/// command name given by the user. All reasonable versions of call_shell()
/// do this.
/// Alternatively, if on Unix and redirecting input or output, but not both,
/// and the 'shelltemp' option isn't set, use pipes.
/// We use input redirection if do_in is true.
/// We use output redirection if do_out is true.
///
/// @param eap  for forced 'ff' and 'fenc'
static void do_filter(linenr_T line1, linenr_T line2, exarg_T *eap, char *cmd, bool do_in,
                     bool do_out)
{
 char *itmp = NULL;
 char *otmp = NULL;
 buf_T *old_curbuf = curbuf;
 int shell_flags = 0;
 const pos_T orig_start = curbuf->b_op_start;
 const pos_T orig_end = curbuf->b_op_end;
 const int stmp = p_stmp;

 if (*cmd == NUL) {        // no filter command
   return;
 }

 const int save_cmod_flags = cmdmod.cmod_flags;
 // Temporarily disable lockmarks since that's needed to propagate changed
 // regions of the buffer for foldUpdate(), linecount, etc.
 cmdmod.cmod_flags &= ~CMOD_LOCKMARKS;

 pos_T cursor_save = curwin->w_cursor;
 linenr_T linecount = line2 - line1 + 1;
 curwin->w_cursor.lnum = line1;
 curwin->w_cursor.col = 0;
 changed_line_abv_curs();
 invalidate_botline_win(curwin);

 // When using temp files:
 // 1. * Form temp file names
 // 2. * Write the lines to a temp file
 // 3.   Run the filter command on the temp file
 // 4. * Read the output of the command into the buffer
 // 5. * Delete the original lines to be filtered
 // 6. * Remove the temp files
 //
 // When writing the input with a pipe or when catching the output with a
 // pipe only need to do 3.

 if (do_out) {
   shell_flags |= kShellOptDoOut;
 }

 if (!do_in && do_out && !stmp) {
   // Use a pipe to fetch stdout of the command, do not use a temp file.
   shell_flags |= kShellOptRead;
   curwin->w_cursor.lnum = line2;
 } else if (do_in && !do_out && !stmp) {
   // Use a pipe to write stdin of the command, do not use a temp file.
   shell_flags |= kShellOptWrite;
   curbuf->b_op_start.lnum = line1;
   curbuf->b_op_end.lnum = line2;
 } else if (do_in && do_out && !stmp) {
   // Use a pipe to write stdin and fetch stdout of the command, do not
   // use a temp file.
   shell_flags |= kShellOptRead | kShellOptWrite;
   curbuf->b_op_start.lnum = line1;
   curbuf->b_op_end.lnum = line2;
   curwin->w_cursor.lnum = line2;
 } else if ((do_in && (itmp = vim_tempname()) == NULL)
            || (do_out && (otmp = vim_tempname()) == NULL)) {
   emsg(_(e_notmp));
   goto filterend;
 }

 // The writing and reading of temp files will not be shown.
 // Vi also doesn't do this and the messages are not very informative.
 no_wait_return++;             // don't call wait_return() while busy
 if (itmp != NULL && buf_write(curbuf, itmp, NULL, line1, line2, eap,
                               false, false, false, true) == FAIL) {
   if (!ui_has(kUIMessages)) {
     msg_putchar('\n');  // Keep message from buf_write().
   }
   no_wait_return--;
   if (!aborting()) {
     // will call wait_return()
     semsg(_("E482: Can't create file %s"), itmp);
   }
   goto filterend;
 }
 if (curbuf != old_curbuf) {
   goto filterend;
 }

 if (!do_out) {
   msg_putchar('\n');
 }

 // Create the shell command in allocated memory.
 char *cmd_buf = make_filter_cmd(cmd, itmp, otmp, do_in);
 ui_cursor_goto(Rows - 1, 0);

 if (do_out) {
   if (u_save(line2, (linenr_T)(line2 + 1)) == FAIL) {
     xfree(cmd_buf);
     goto error;
   }
   redraw_curbuf_later(UPD_VALID);
 }
 linenr_T read_linecount = curbuf->b_ml.ml_line_count;

 // Pass on the kShellOptDoOut flag when the output is being redirected.
 call_shell(cmd_buf, kShellOptFilter | shell_flags, NULL);
 xfree(cmd_buf);

 did_check_timestamps = false;
 need_check_timestamps = true;

 // When interrupting the shell command, it may still have produced some
 // useful output.  Reset got_int here, so that readfile() won't cancel
 // reading.
 os_breakcheck();
 got_int = false;

 if (do_out) {
   if (otmp != NULL) {
     if (readfile(otmp, NULL, line2, 0, (linenr_T)MAXLNUM, eap,
                  READ_FILTER, false) != OK) {
       if (!aborting()) {
         msg_putchar('\n');
         semsg(_(e_cant_read_file_str), otmp);
       }
       goto error;
     }
     if (curbuf != old_curbuf) {
       goto filterend;
     }
   }

   read_linecount = curbuf->b_ml.ml_line_count - read_linecount;

   if (shell_flags & kShellOptRead) {
     curbuf->b_op_start.lnum = line2 + 1;
     curbuf->b_op_end.lnum = curwin->w_cursor.lnum;
     appended_lines_mark(line2, read_linecount);
   }

   if (do_in) {
     if ((cmdmod.cmod_flags & CMOD_KEEPMARKS)
         || vim_strchr(p_cpo, CPO_REMMARK) == NULL) {
       // TODO(bfredl): Currently not active for extmarks. What would we
       // do if columns don't match, assume added/deleted bytes at the
       // end of each line?
       if (read_linecount >= linecount) {
         // move all marks from old lines to new lines
         mark_adjust(line1, line2, linecount, 0, kExtmarkNOOP);
       } else {
         // move marks from old lines to new lines, delete marks
         // that are in deleted lines
         mark_adjust(line1, line1 + read_linecount - 1, linecount, 0,
                     kExtmarkNOOP);
         mark_adjust(line1 + read_linecount, line2, MAXLNUM, 0,
                     kExtmarkNOOP);
       }
     }

     // Put cursor on first filtered line for ":range!cmd".
     // Adjust '[ and '] (set by buf_write()).
     curwin->w_cursor.lnum = line1;
     del_lines(linecount, true);
     curbuf->b_op_start.lnum -= linecount;             // adjust '[
     curbuf->b_op_end.lnum -= linecount;               // adjust ']
     write_lnum_adjust(-linecount);                    // adjust last line
                                                       // for next write
     foldUpdate(curwin, curbuf->b_op_start.lnum, curbuf->b_op_end.lnum);
   } else {
     // Put cursor on last new line for ":r !cmd".
     linecount = curbuf->b_op_end.lnum - curbuf->b_op_start.lnum + 1;
     curwin->w_cursor.lnum = curbuf->b_op_end.lnum;
   }

   beginline(BL_WHITE | BL_FIX);           // cursor on first non-blank
   no_wait_return--;

   if (linecount > p_report) {
     if (do_in) {
       vim_snprintf(msg_buf, sizeof(msg_buf),
                    _("%" PRId64 " lines filtered"), (int64_t)linecount);
       if (msg(msg_buf, 0) && !msg_scroll) {
         // save message to display it after redraw
         set_keep_msg(msg_buf, 0);
       }
     } else {
       msgmore(linecount);
     }
   }
 } else {
error:
   // put cursor back in same position for ":w !cmd"
   curwin->w_cursor = cursor_save;
   no_wait_return--;
   wait_return(false);
 }

filterend:

 cmdmod.cmod_flags = save_cmod_flags;
 if (curbuf != old_curbuf) {
   no_wait_return--;
   emsg(_("E135: *Filter* Autocommands must not change current buffer"));
 } else if (cmdmod.cmod_flags & CMOD_LOCKMARKS) {
   curbuf->b_op_start = orig_start;
   curbuf->b_op_end = orig_end;
 }

 if (itmp != NULL) {
   os_remove(itmp);
 }
 if (otmp != NULL) {
   os_remove(otmp);
 }
 xfree(itmp);
 xfree(otmp);
}

/// Call a shell to execute a command.
/// When "cmd" is NULL start an interactive shell.
///
/// @param flags  may be SHELL_DOOUT when output is redirected
void do_shell(char *cmd, int flags)
{
 // Disallow shell commands in secure mode
 if (check_secure()) {
   msg_end();
   return;
 }

 // For autocommands we want to get the output on the current screen, to
 // avoid having to type return below.
 msg_putchar('\r');                    // put cursor at start of line
 msg_putchar('\n');                    // may shift screen one line up

 // warning message before calling the shell
 if (p_warn
     && !autocmd_busy
     && msg_silent == 0) {
   FOR_ALL_BUFFERS(buf) {
     if (bufIsChanged(buf)) {
       msg_puts(_("[No write since last change]\n"));
       break;
     }
   }
 }

 // This ui_cursor_goto is required for when the '\n' resulted in a "delete line
 // 1" command to the terminal.
 ui_cursor_goto(msg_row, msg_col);
 call_shell(cmd, flags, NULL);
 if (msg_silent == 0) {
   msg_didout = true;
 }
 did_check_timestamps = false;
 need_check_timestamps = true;

 // put the message cursor at the end of the screen, avoids wait_return()
 // to overwrite the text that the external command showed
 msg_row = Rows - 1;
 msg_col = 0;

 apply_autocmds(EVENT_SHELLCMDPOST, NULL, NULL, false, curbuf);
}

#if !defined(UNIX)
static char *find_pipe(const char *cmd)
{
 bool inquote = false;

 for (const char *p = cmd; *p != NUL; p++) {
   if (!inquote && *p == '|') {
     return (char *)p;
   }
   if (*p == '"') {
     inquote = !inquote;
   } else if (rem_backslash(p)) {
     p++;
   }
 }
 return NULL;
}
#endif

/// Create a shell command from a command string, input redirection file and
/// output redirection file.
///
/// @param cmd  Command to execute.
/// @param itmp NULL or the input file.
/// @param otmp NULL or the output file.
/// @param do_in true if stdin is needed.
/// @returns an allocated string with the shell command.
char *make_filter_cmd(char *cmd, char *itmp, char *otmp, bool do_in)
{
 bool is_fish_shell =
#if defined(UNIX)
   strncmp(invocation_path_tail(p_sh, NULL), "fish", 4) == 0;
#else
   false;
#endif
 bool is_pwsh = strncmp(invocation_path_tail(p_sh, NULL), "pwsh", 4) == 0
                || strncmp(invocation_path_tail(p_sh, NULL), "powershell",
                           10) == 0;

 size_t len = strlen(cmd) + 1;  // At least enough space for cmd + NULL.

 len += is_fish_shell ? sizeof("begin; " "; end") - 1
                      : !is_pwsh ? sizeof("(" ")") - 1
                                 : 0;

 if (itmp != NULL) {
   len += is_pwsh ? strlen(itmp) + sizeof("& { Get-Content " " | & " " }") - 1 + 6  // +6: #20530
                  : strlen(itmp) + sizeof(" { " " < " " } ") - 1;
 }

 if (do_in && is_pwsh) {
   len += sizeof(" $input | ");
 }

 if (otmp != NULL) {
   len += strlen(otmp) + strlen(p_srr) + 2;  // two extra spaces ("  "),
 }

 char *const buf = xmalloc(len);

 if (is_pwsh) {
   if (itmp != NULL) {
     xstrlcpy(buf, "& { Get-Content ", len - 1);  // FIXME: should we add "-Encoding utf8"?
     xstrlcat(buf, itmp, len - 1);
     xstrlcat(buf, " | & ", len - 1);  // FIXME: add `&` ourself or leave to user?
     xstrlcat(buf, cmd, len - 1);
     xstrlcat(buf, " }", len - 1);
   } else if (do_in) {
     xstrlcpy(buf, " $input | ", len - 1);
     xstrlcat(buf, cmd, len);
   } else {
     xstrlcpy(buf, cmd, len);
   }
 } else {
#if defined(UNIX)
   // Put delimiters around the command (for concatenated commands) when
   // redirecting input and/or output.
   if (itmp != NULL || otmp != NULL) {
     char *fmt = is_fish_shell ? "begin; %s; end"
                               : "(%s)";
     vim_snprintf(buf, len, fmt, cmd);
   } else {
     xstrlcpy(buf, cmd, len);
   }

   if (itmp != NULL) {
     xstrlcat(buf, " < ", len - 1);
     xstrlcat(buf, itmp, len - 1);
   }
#else
   // For shells that don't understand braces around commands, at least allow
   // the use of commands in a pipe.
   xstrlcpy(buf, cmd, len);
   if (itmp != NULL) {
     // If there is a pipe, we have to put the '<' in front of it.
     // Don't do this when 'shellquote' is not empty, otherwise the
     // redirection would be inside the quotes.
     if (*p_shq == NUL) {
       char *const p = find_pipe(buf);
       if (p != NULL) {
         *p = NUL;
       }
     }
     xstrlcat(buf, " < ", len);
     xstrlcat(buf, itmp, len);
     if (*p_shq == NUL) {
       const char *const p = find_pipe(cmd);
       if (p != NULL) {
         xstrlcat(buf, " ", len - 1);  // Insert a space before the '|' for DOS
         xstrlcat(buf, p, len - 1);
       }
     }
   }
#endif
 }
 if (otmp != NULL) {
   append_redir(buf, len, p_srr, otmp);
 }
 return buf;
}

/// Append output redirection for the given file to the end of the buffer
///
/// @param[out]  buf  Buffer to append to.
/// @param[in]  buflen  Buffer length.
/// @param[in]  opt  Separator or format string to append: will append
///                  `printf(' ' . opt, fname)` if `%s` is found in `opt` or
///                  a space, opt, a space and then fname if `%s` is not found
///                  there.
/// @param[in]  fname  File name to append.
void append_redir(char *const buf, const size_t buflen, const char *const opt,
                 const char *const fname)
{
 char *const end = buf + strlen(buf);
 // find "%s"
 const char *p = opt;
 for (; (p = strchr(p, '%')) != NULL; p++) {
   if (p[1] == 's') {  // found %s
     break;
   } else if (p[1] == '%') {  // skip %%
     p++;
   }
 }
 if (p != NULL) {
   *end = ' ';  // not really needed? Not with sh, ksh or bash
   vim_snprintf(end + 1, (size_t)((ptrdiff_t)buflen - (end + 1 - buf)), opt, fname);
 } else {
   vim_snprintf(end, (size_t)((ptrdiff_t)buflen - (end - buf)), " %s %s", opt, fname);
 }
}

void print_line_no_prefix(linenr_T lnum, bool use_number, bool list)
{
 char numbuf[30];

 if (curwin->w_p_nu || use_number) {
   vim_snprintf(numbuf, sizeof(numbuf), "%*" PRIdLINENR " ",
                number_width(curwin), lnum);
   msg_puts_hl(numbuf, HLF_N + 1, false);  // Highlight line nrs.
 }
 msg_prt_line(ml_get(lnum), list);
}

static bool global_need_msg_kind = false;  // Start new message only once during :global.

/// Print a text line.  Also in silent mode ("ex -s").
void print_line(linenr_T lnum, bool use_number, bool list, bool first)
{
 bool save_silent = silent_mode;

 // apply :filter /pat/
 if (message_filtered(ml_get(lnum))) {
   return;
 }

 silent_mode = false;
 info_message = true;  // use stdout, not stderr
 if ((!global_busy || global_need_msg_kind) && first) {
   msg_start();
   msg_ext_set_kind("list_cmd");
   global_need_msg_kind = false;
 } else if (!save_silent) {
   msg_putchar('\n');  // don't want trailing newline with regular messaging
 }
 print_line_no_prefix(lnum, use_number, list);
 if (save_silent) {
   msg_putchar('\n');  // batch mode message should always end in newline
   silent_mode = save_silent;
 }
 info_message = false;
}

int rename_buffer(char *new_fname)
{
 buf_T *buf = curbuf;
 apply_autocmds(EVENT_BUFFILEPRE, NULL, NULL, false, curbuf);
 // buffer changed, don't change name now
 if (buf != curbuf) {
   return FAIL;
 }
 if (aborting()) {         // autocmds may abort script processing
   return FAIL;
 }
 // The name of the current buffer will be changed.
 // A new (unlisted) buffer entry needs to be made to hold the old file
 // name, which will become the alternate file name.
 // But don't set the alternate file name if the buffer didn't have a
 // name.
 char *fname = curbuf->b_ffname;
 char *sfname = curbuf->b_sfname;
 char *xfname = curbuf->b_fname;
 curbuf->b_ffname = NULL;
 curbuf->b_sfname = NULL;
 if (setfname(curbuf, new_fname, NULL, true) == FAIL) {
   curbuf->b_ffname = fname;
   curbuf->b_sfname = sfname;
   return FAIL;
 }
 curbuf->b_flags |= BF_NOTEDITED;
 if (xfname != NULL && *xfname != NUL) {
   buf = buflist_new(fname, xfname, curwin->w_cursor.lnum, 0);
   if (buf != NULL && (cmdmod.cmod_flags & CMOD_KEEPALT) == 0) {
     curwin->w_alt_fnum = buf->b_fnum;
   }
 }
 xfree(fname);
 xfree(sfname);
 apply_autocmds(EVENT_BUFFILEPOST, NULL, NULL, false, curbuf);
 // Change directories when the 'acd' option is set.
 do_autochdir();
 return OK;
}

/// ":file[!] [fname]".
void ex_file(exarg_T *eap)
{
 // ":0file" removes the file name.  Check for illegal uses ":3file",
 // "0file name", etc.
 if (eap->addr_count > 0
     && (*eap->arg != NUL
         || eap->line2 > 0
         || eap->addr_count > 1)) {
   emsg(_(e_invarg));
   return;
 }

 if (*eap->arg != NUL || eap->addr_count == 1) {
   if (rename_buffer(eap->arg) == FAIL) {
     return;
   }
   redraw_tabline = true;
 }

 // print file name if no argument or 'F' is not in 'shortmess'
 if (*eap->arg == NUL || !shortmess(SHM_FILEINFO)) {
   fileinfo(false, false, eap->forceit);
 }
}

/// ":update".
void ex_update(exarg_T *eap)
{
 if (curbufIsChanged()
     || (!bt_nofilename(curbuf) && curbuf->b_ffname != NULL
         && !os_path_exists(curbuf->b_ffname))) {
   do_write(eap);
 }
}

/// ":write" and ":saveas".
void ex_write(exarg_T *eap)
{
 if (eap->cmdidx == CMD_saveas) {
   // :saveas does not take a range, uses all lines.
   eap->line1 = 1;
   eap->line2 = curbuf->b_ml.ml_line_count;
 }

 if (eap->usefilter) {  // input lines to shell command
   do_bang(1, eap, false, true, false);
 } else {
   do_write(eap);
 }
}

#ifdef UNIX
static int check_writable(const char *fname)
{
 if (os_nodetype(fname) == NODE_OTHER) {
   semsg(_("E503: \"%s\" is not a file or writable device"), fname);
   return FAIL;
 }
 return OK;
}
#endif

static int handle_mkdir_p_arg(exarg_T *eap, char *fname)
{
 if (eap->mkdir_p && os_file_mkdir(fname, 0755) < 0) {
   return FAIL;
 }

 return OK;
}

/// Write current buffer to file "eap->arg".
/// If "eap->append" is true, append to the file.
///
/// If "*eap->arg == NUL" write to current file.
///
/// @return  FAIL for failure, OK otherwise.
int do_write(exarg_T *eap)
{
 bool other;
 char *fname = NULL;            // init to shut up gcc
 int retval = FAIL;
 char *free_fname = NULL;
 buf_T *alt_buf = NULL;

 if (not_writing()) {          // check 'write' option
   return FAIL;
 }

 char *ffname = eap->arg;
 if (*ffname == NUL) {
   if (eap->cmdidx == CMD_saveas) {
     emsg(_(e_argreq));
     goto theend;
   }
   other = false;
 } else {
   fname = ffname;
   free_fname = fix_fname(ffname);
   // When out-of-memory, keep unexpanded file name, because we MUST be
   // able to write the file in this situation.
   if (free_fname != NULL) {
     ffname = free_fname;
   }
   other = otherfile(ffname);
 }

 // If we have a new file, put its name in the list of alternate file names.
 if (other) {
   if (vim_strchr(p_cpo, CPO_ALTWRITE) != NULL
       || eap->cmdidx == CMD_saveas) {
     alt_buf = setaltfname(ffname, fname, 1);
   } else {
     alt_buf = buflist_findname(ffname);
   }
   if (alt_buf != NULL && alt_buf->b_ml.ml_mfp != NULL) {
     // Overwriting a file that is loaded in another buffer is not a
     // good idea.
     emsg(_(e_bufloaded));
     goto theend;
   }
 }

 // Writing to the current file is not allowed in readonly mode
 // and a file name is required.
 // "nofile" and "nowrite" buffers cannot be written implicitly either.
 if (!other && (bt_dontwrite_msg(curbuf)
                || check_fname() == FAIL
#ifdef UNIX
                || check_writable(curbuf->b_ffname) == FAIL
#endif
                || check_readonly(&eap->forceit, curbuf))) {
   goto theend;
 }

 if (!other) {
   ffname = curbuf->b_ffname;
   fname = curbuf->b_fname;
   // Not writing the whole file is only allowed with '!'.
   if ((eap->line1 != 1
        || eap->line2 != curbuf->b_ml.ml_line_count)
       && !eap->forceit
       && !eap->append
       && !p_wa) {
     if (p_confirm || (cmdmod.cmod_flags & CMOD_CONFIRM)) {
       if (vim_dialog_yesno(VIM_QUESTION, NULL,
                            _("Write partial file?"), 2) != VIM_YES) {
         goto theend;
       }
       eap->forceit = true;
     } else {
       emsg(_("E140: Use ! to write partial buffer"));
       goto theend;
     }
   }
 }

 if (check_overwrite(eap, curbuf, fname, ffname, other) == OK) {
   if (eap->cmdidx == CMD_saveas && alt_buf != NULL) {
     buf_T *was_curbuf = curbuf;

     apply_autocmds(EVENT_BUFFILEPRE, NULL, NULL, false, curbuf);
     apply_autocmds(EVENT_BUFFILEPRE, NULL, NULL, false, alt_buf);
     if (curbuf != was_curbuf || aborting()) {
       // buffer changed, don't change name now
       retval = FAIL;
       goto theend;
     }
     // Exchange the file names for the current and the alternate
     // buffer.  This makes it look like we are now editing the buffer
     // under the new name.  Must be done before buf_write(), because
     // if there is no file name and 'cpo' contains 'F', it will set
     // the file name.
     fname = alt_buf->b_fname;
     alt_buf->b_fname = curbuf->b_fname;
     curbuf->b_fname = fname;
     fname = alt_buf->b_ffname;
     alt_buf->b_ffname = curbuf->b_ffname;
     curbuf->b_ffname = fname;
     fname = alt_buf->b_sfname;
     alt_buf->b_sfname = curbuf->b_sfname;
     curbuf->b_sfname = fname;
     buf_name_changed(curbuf);
     apply_autocmds(EVENT_BUFFILEPOST, NULL, NULL, false, curbuf);
     apply_autocmds(EVENT_BUFFILEPOST, NULL, NULL, false, alt_buf);
     if (!alt_buf->b_p_bl) {
       alt_buf->b_p_bl = true;
       apply_autocmds(EVENT_BUFADD, NULL, NULL, false, alt_buf);
     }
     if (curbuf != was_curbuf || aborting()) {
       // buffer changed, don't write the file
       retval = FAIL;
       goto theend;
     }

     // If 'filetype' was empty try detecting it now.
     if (*curbuf->b_p_ft == NUL) {
       if (augroup_exists("filetypedetect")) {
         do_doautocmd("filetypedetect BufRead", true, NULL);
       }
       do_modelines(0);
     }

     // Autocommands may have changed buffer names, esp. when
     // 'autochdir' is set.
     fname = curbuf->b_sfname;
   }

   if (handle_mkdir_p_arg(eap, fname) == FAIL) {
     retval = FAIL;
     goto theend;
   }

   int name_was_missing = curbuf->b_ffname == NULL;
   retval = buf_write(curbuf, ffname, fname, eap->line1, eap->line2,
                      eap, eap->append, eap->forceit, true, false);

   // After ":saveas fname" reset 'readonly'.
   if (eap->cmdidx == CMD_saveas) {
     if (retval == OK) {
       curbuf->b_p_ro = false;
       redraw_tabline = true;
     }
   }

   // Change directories when the 'acd' option is set and the file name
   // got changed or set.
   if (eap->cmdidx == CMD_saveas || name_was_missing) {
     do_autochdir();
   }
 }

theend:
 xfree(free_fname);
 return retval;
}

/// Check if it is allowed to overwrite a file.  If b_flags has BF_NOTEDITED,
/// BF_NEW or BF_READERR, check for overwriting current file.
/// May set eap->forceit if a dialog says it's OK to overwrite.
///
/// @param fname   file name to be used (can differ from buf->ffname)
/// @param ffname  full path version of fname
/// @param other   writing under other name
///
/// @return  OK if it's OK, FAIL if it is not.
int check_overwrite(exarg_T *eap, buf_T *buf, char *fname, char *ffname, bool other)
{
 // Write to another file or b_flags set or not writing the whole file:
 // overwriting only allowed with '!'
 // If "other" is false and bt_nofilename(buf) is true, this must be
 // writing an "acwrite" buffer to the same file as its b_ffname, and
 // buf_write() will only allow writing with BufWriteCmd autocommands,
 // so there is no need for an overwrite check.
 if ((other
      || (!bt_nofilename(buf)
          && ((buf->b_flags & BF_NOTEDITED)
              || ((buf->b_flags & BF_NEW)
                  && vim_strchr(p_cpo, CPO_OVERNEW) == NULL)
              || (buf->b_flags & BF_READERR))))
     && !p_wa
     && os_path_exists(ffname)) {
   if (!eap->forceit && !eap->append) {
#ifdef UNIX
     // It is possible to open a directory on Unix.
     if (os_isdir(ffname)) {
       semsg(_(e_isadir2), ffname);
       return FAIL;
     }
#endif
     if (p_confirm || (cmdmod.cmod_flags & CMOD_CONFIRM)) {
       char buff[DIALOG_MSG_SIZE];

       dialog_msg(buff, _("Overwrite existing file \"%s\"?"), fname);
       if (vim_dialog_yesno(VIM_QUESTION, NULL, buff, 2) != VIM_YES) {
         return FAIL;
       }
       eap->forceit = true;
     } else {
       emsg(_(e_exists));
       return FAIL;
     }
   }

   // For ":w! filename" check that no swap file exists for "filename".
   if (other && !emsg_silent) {
     char *dir;

     // We only try the first entry in 'directory', without checking if
     // it's writable.  If the "." directory is not writable the write
     // will probably fail anyway.
     // Use 'shortname' of the current buffer, since there is no buffer
     // for the written file.
     if (*p_dir == NUL) {
       dir = xmalloc(5);
       STRCPY(dir, ".");
     } else {
       dir = xmalloc(MAXPATHL);
       char *p = p_dir;
       copy_option_part(&p, dir, MAXPATHL, ",");
     }
     char *swapname = makeswapname(fname, ffname, curbuf, dir);
     xfree(dir);
     if (os_path_exists(swapname)) {
       if (p_confirm || (cmdmod.cmod_flags & CMOD_CONFIRM)) {
         char buff[DIALOG_MSG_SIZE];

         dialog_msg(buff,
                    _("Swap file \"%s\" exists, overwrite anyway?"),
                    swapname);
         if (vim_dialog_yesno(VIM_QUESTION, NULL, buff, 2)
             != VIM_YES) {
           xfree(swapname);
           return FAIL;
         }
         eap->forceit = true;
       } else {
         semsg(_("E768: Swap file exists: %s (:silent! overrides)"),
               swapname);
         xfree(swapname);
         return FAIL;
       }
     }
     xfree(swapname);
   }
 }
 return OK;
}

/// Handle ":wnext", ":wNext" and ":wprevious" commands.
void ex_wnext(exarg_T *eap)
{
 int i;

 if (eap->cmd[1] == 'n') {
   i = curwin->w_arg_idx + (int)eap->line2;
 } else {
   i = curwin->w_arg_idx - (int)eap->line2;
 }
 eap->line1 = 1;
 eap->line2 = curbuf->b_ml.ml_line_count;
 if (do_write(eap) != FAIL) {
   do_argfile(eap, i);
 }
}

/// ":wall", ":wqall" and ":xall": Write all changed files (and exit).
void do_wqall(exarg_T *eap)
{
 int error = 0;
 int save_forceit = eap->forceit;
 bool save_exiting = exiting;

 if (eap->cmdidx == CMD_xall || eap->cmdidx == CMD_wqall) {
   if (before_quit_all(eap) == FAIL) {
     return;
   }
   exiting = true;
 }

 FOR_ALL_BUFFERS(buf) {
   if (exiting && !eap->forceit
       && buf->terminal
       // TODO(zeertzjq): this always returns false for nvim_open_term() terminals.
       // Use terminal_running() instead?
       && channel_job_running((uint64_t)buf->b_p_channel)) {
     no_write_message_buf(buf);
     error++;
   } else if (!bufIsChanged(buf) || bt_dontwrite(buf)) {
     continue;
   }
   // Check if there is a reason the buffer cannot be written:
   // 1. if the 'write' option is set
   // 2. if there is no file name (even after browsing)
   // 3. if the 'readonly' is set (even after a dialog)
   // 4. if overwriting is allowed (even after a dialog)
   if (not_writing()) {
     error++;
     break;
   }
   if (buf->b_ffname == NULL) {
     semsg(_("E141: No file name for buffer %" PRId64), (int64_t)buf->b_fnum);
     error++;
   } else if (check_readonly(&eap->forceit, buf)
              || check_overwrite(eap, buf, buf->b_fname, buf->b_ffname, false) == FAIL) {
     error++;
   } else {
     bufref_T bufref;
     set_bufref(&bufref, buf);
     if (handle_mkdir_p_arg(eap, buf->b_fname) == FAIL
         || buf_write_all(buf, eap->forceit) == FAIL) {
       error++;
     }
     // An autocommand may have deleted the buffer.
     if (!bufref_valid(&bufref)) {
       buf = firstbuf;
     }
   }
   eap->forceit = save_forceit;          // check_overwrite() may set it
 }
 if (exiting) {
   if (!error) {
     getout(0);                // exit Vim
   }
   not_exiting(save_exiting);
 }
}

/// Check the 'write' option.
///
/// @return  true and give a message when it's not st.
static bool not_writing(void)
{
 if (p_write) {
   return false;
 }
 emsg(_("E142: File not written: Writing is disabled by 'write' option"));
 return true;
}

/// Check if a buffer is read-only (either 'readonly' option is set or file is
/// read-only). Ask for overruling in a dialog. Return true and give an error
/// message when the buffer is readonly.
static int check_readonly(int *forceit, buf_T *buf)
{
 // Handle a file being readonly when the 'readonly' option is set or when
 // the file exists and permissions are read-only.
 if (!*forceit && (buf->b_p_ro
                   || (os_path_exists(buf->b_ffname)
                       && !os_file_is_writable(buf->b_ffname)))) {
   if ((p_confirm || (cmdmod.cmod_flags & CMOD_CONFIRM)) && buf->b_fname != NULL) {
     char buff[DIALOG_MSG_SIZE];

     if (buf->b_p_ro) {
       dialog_msg(buff,
                  _("'readonly' option is set for \"%s\".\nDo you wish to write anyway?"),
                  buf->b_fname);
     } else {
       dialog_msg(buff,
                  _("File permissions of \"%s\" are read-only.\nIt may still be possible to "
                    "write it.\nDo you wish to try?"),
                  buf->b_fname);
     }

     if (vim_dialog_yesno(VIM_QUESTION, NULL, buff, 2) == VIM_YES) {
       // Set forceit, to force the writing of a readonly file
       *forceit = true;
       return false;
     }
     return true;
   } else if (buf->b_p_ro) {
     emsg(_(e_readonly));
   } else {
     semsg(_("E505: \"%s\" is read-only (add ! to override)"),
           buf->b_fname);
   }
   return true;
 }

 return false;
}

/// Try to abandon the current file and edit a new or existing file.
///
/// @param fnum  the number of the file, if zero use "ffname_arg"/"sfname_arg".
/// @param lnum  the line number for the cursor in the new file (if non-zero).
///
/// @return:
///           GETFILE_ERROR for "normal" error,
///           GETFILE_NOT_WRITTEN for "not written" error,
///           GETFILE_SAME_FILE for success
///           GETFILE_OPEN_OTHER for successfully opening another file.
int getfile(int fnum, char *ffname_arg, char *sfname_arg, bool setpm, linenr_T lnum, bool forceit)
{
 if (!check_can_set_curbuf_forceit(forceit)) {
   return GETFILE_ERROR;
 }

 char *ffname = ffname_arg;
 char *sfname = sfname_arg;
 bool other;
 int retval;
 char *free_me = NULL;

 if (text_locked()) {
   return GETFILE_ERROR;
 }
 if (curbuf_locked()) {
   return GETFILE_ERROR;
 }

 if (fnum == 0) {
   // make ffname full path, set sfname
   fname_expand(curbuf, &ffname, &sfname);
   other = otherfile(ffname);
   free_me = ffname;                   // has been allocated, free() later
 } else {
   other = (fnum != curbuf->b_fnum);
 }

 if (other) {
   no_wait_return++;               // don't wait for autowrite message
 }
 if (other && !forceit && curbuf->b_nwindows == 1 && !buf_hide(curbuf)
     && curbufIsChanged() && autowrite(curbuf, forceit) == FAIL) {
   if (p_confirm && p_write) {
     dialog_changed(curbuf, false);
   }
   if (curbufIsChanged()) {
     no_wait_return--;
     no_write_message();
     retval = GETFILE_NOT_WRITTEN;     // File has been changed.
     goto theend;
   }
 }
 if (other) {
   no_wait_return--;
 }
 if (setpm) {
   setpcmark();
 }
 if (!other) {
   if (lnum != 0) {
     curwin->w_cursor.lnum = lnum;
   }
   check_cursor_lnum(curwin);
   beginline(BL_SOL | BL_FIX);
   retval = GETFILE_SAME_FILE;     // it's in the same file
 } else if (do_ecmd(fnum, ffname, sfname, NULL, lnum,
                    (buf_hide(curbuf) ? ECMD_HIDE : 0)
                    + (forceit ? ECMD_FORCEIT : 0), curwin) == OK) {
   retval = GETFILE_OPEN_OTHER;    // opened another file
 } else {
   retval = GETFILE_ERROR;         // error encountered
 }

theend:
 xfree(free_me);
 return retval;
}

/// set v:swapcommand for the SwapExists autocommands.
///
/// @param command  [+cmd] to be executed (e.g. +10).
/// @param newlnum  if > 0: put cursor on this line number (if possible)
//
/// @return 1 if swapcommand was actually set, 0 otherwise
bool set_swapcommand(char *command, linenr_T newlnum)
{
 if ((command == NULL && newlnum <= 0) || *get_vim_var_str(VV_SWAPCOMMAND) != NUL) {
   return false;
 }
 const size_t len = (command != NULL) ? strlen(command) + 3 : 30;
 char *const p = xmalloc(len);
 if (command != NULL) {
   vim_snprintf(p, len, ":%s\r", command);
 } else {
   vim_snprintf(p, len, "%" PRId64 "G", (int64_t)newlnum);
 }
 set_vim_var_string(VV_SWAPCOMMAND, p, -1);
 xfree(p);
 return true;
}

/// start editing a new file
///
/// @param fnum     file number; if zero use ffname/sfname
/// @param ffname   the file name
///                 - full path if sfname used,
///                 - any file name if sfname is NULL
///                 - empty string to re-edit with the same file name (but may
///                   be in a different directory)
///                 - NULL to start an empty buffer
/// @param sfname   the short file name (or NULL)
/// @param eap      contains the command to be executed after loading the file
///                 and forced 'ff' and 'fenc'. Can be NULL!
/// @param newlnum  if > 0: put cursor on this line number (if possible)
///                 ECMD_LASTL: use last position in loaded file
///                 ECMD_LAST: use last position in all files
///                 ECMD_ONE: use first line
/// @param flags    ECMD_HIDE: if true don't free the current buffer
///                 ECMD_SET_HELP: set b_help flag of (new) buffer before
///                 opening file
///                 ECMD_OLDBUF: use existing buffer if it exists
///                 ECMD_FORCEIT: ! used for Ex command
///                 ECMD_ADDBUF: don't edit, just add to buffer list
///                 ECMD_ALTBUF: like ECMD_ADDBUF and also set the alternate
///                 file
///                 ECMD_NOWINENTER: Do not trigger BufWinEnter
/// @param oldwin   Should be "curwin" when editing a new buffer in the current
///                 window, NULL when splitting the window first.  When not NULL
///                 info of the previous buffer for "oldwin" is stored.
///
/// @return FAIL for failure, OK otherwise
int do_ecmd(int fnum, char *ffname, char *sfname, exarg_T *eap, linenr_T newlnum, int flags,
           win_T *oldwin)
{
 bool other_file;                      // true if editing another file
 int oldbuf;                           // true if using existing buffer
 bool auto_buf = false;                // true if autocommands brought us
                                       // into the buffer unexpectedly
 char *new_name = NULL;
 bool did_set_swapcommand = false;
 buf_T *buf;
 bufref_T bufref;
 bufref_T old_curbuf;
 char *free_fname = NULL;
 int retval = FAIL;
 linenr_T topline = 0;
 int newcol = -1;
 int solcol = -1;
 char *command = NULL;
 bool did_get_winopts = false;
 int readfile_flags = 0;
 bool did_inc_redrawing_disabled = false;
 OptInt *so_ptr = curwin->w_p_so >= 0 ? &curwin->w_p_so : &p_so;

 if (eap != NULL) {
   command = eap->do_ecmd_cmd;
 }

 set_bufref(&old_curbuf, curbuf);

 if (fnum != 0) {
   if (fnum == curbuf->b_fnum) {       // file is already being edited
     return OK;                        // nothing to do
   }
   other_file = true;
 } else {
   // if no short name given, use ffname for short name
   if (sfname == NULL) {
     sfname = ffname;
   }
#ifdef CASE_INSENSITIVE_FILENAME
   if (sfname != NULL) {
     path_fix_case(sfname);             // set correct case for sfname
   }
#endif

   if ((flags & (ECMD_ADDBUF | ECMD_ALTBUF))
       && (ffname == NULL || *ffname == NUL)) {
     goto theend;
   }

   if (ffname == NULL) {
     other_file = true;
   } else if (*ffname == NUL && curbuf->b_ffname == NULL) {  // there is no file name
     other_file = false;
   } else {
     if (*ffname == NUL) {                 // re-edit with same file name
       ffname = curbuf->b_ffname;
       sfname = curbuf->b_fname;
     }
     free_fname = fix_fname(ffname);       // may expand to full path name
     if (free_fname != NULL) {
       ffname = free_fname;
     }
     other_file = otherfile(ffname);
   }
 }

 // Re-editing a terminal buffer: skip most buffer re-initialization.
 if (!other_file && curbuf->terminal) {
   check_arg_idx(curwin);  // Needed when called from do_argfile().
   maketitle();            // Title may show the arg index, e.g. "(2 of 5)".
   retval = OK;
   goto theend;
 }

 // If the file was changed we may not be allowed to abandon it:
 // - if we are going to re-edit the same file
 // - or if we are the only window on this file and if ECMD_HIDE is false
 if (((!other_file && !(flags & ECMD_OLDBUF))
      || (curbuf->b_nwindows == 1
          && !(flags & (ECMD_HIDE | ECMD_ADDBUF | ECMD_ALTBUF))))
     && check_changed(curbuf, (p_awa ? CCGD_AW : 0)
                      | (other_file ? 0 : CCGD_MULTWIN)
                      | ((flags & ECMD_FORCEIT) ? CCGD_FORCEIT : 0)
                      | (eap == NULL ? 0 : CCGD_EXCMD))) {
   if (fnum == 0 && other_file && ffname != NULL) {
     setaltfname(ffname, sfname, newlnum < 0 ? 0 : newlnum);
   }
   goto theend;
 }

 // End Visual mode before switching to another buffer, so the text can be
 // copied into the GUI selection buffer.
 // Careful: may trigger ModeChanged() autocommand

 // Should we block autocommands here?
 reset_VIsual();

 // autocommands freed window :(
 if (oldwin != NULL && !win_valid(oldwin)) {
   oldwin = NULL;
 }

 did_set_swapcommand = set_swapcommand(command, newlnum);

 // If we are starting to edit another file, open a (new) buffer.
 // Otherwise we re-use the current buffer.
 if (other_file) {
   const int prev_alt_fnum = curwin->w_alt_fnum;

   if (!(flags & (ECMD_ADDBUF | ECMD_ALTBUF))) {
     if ((cmdmod.cmod_flags & CMOD_KEEPALT) == 0) {
       curwin->w_alt_fnum = curbuf->b_fnum;
     }
     if (oldwin != NULL) {
       buflist_altfpos(oldwin);
     }
   }

   if (fnum) {
     buf = buflist_findnr(fnum);
   } else {
     if (flags & (ECMD_ADDBUF | ECMD_ALTBUF)) {
       // Default the line number to zero to avoid that a wininfo item
       // is added for the current window.
       linenr_T tlnum = 0;

       if (command != NULL) {
         tlnum = (linenr_T)atol(command);
         if (tlnum <= 0) {
           tlnum = 1;
         }
       }
       // Add BLN_NOCURWIN to avoid a new wininfo items are associated
       // with the current window.
       const buf_T *const newbuf
         = buflist_new(ffname, sfname, tlnum, BLN_LISTED | BLN_NOCURWIN);
       if (newbuf != NULL && (flags & ECMD_ALTBUF)) {
         curwin->w_alt_fnum = newbuf->b_fnum;
       }
       goto theend;
     }
     buf = buflist_new(ffname, sfname, 0,
                       BLN_CURBUF | (flags & ECMD_SET_HELP ? 0 : BLN_LISTED));
     // Autocmds may change curwin and curbuf.
     if (oldwin != NULL) {
       oldwin = curwin;
     }
     set_bufref(&old_curbuf, curbuf);
   }
   if (buf == NULL) {
     goto theend;
   }
   // autocommands try to edit a closing buffer, which like splitting, can
   // result in more windows displaying it; abort
   if (buf->b_locked_split) {
     // window was split, but not editing the new buffer, reset b_nwindows again
     if (oldwin == NULL
         && curwin->w_buffer != NULL
         && curwin->w_buffer->b_nwindows > 1) {
       curwin->w_buffer->b_nwindows--;
     }
     emsg(_(e_cannot_switch_to_a_closing_buffer));
     goto theend;
   }
   if (curwin->w_alt_fnum == buf->b_fnum && prev_alt_fnum != 0) {
     // reusing the buffer, keep the old alternate file
     curwin->w_alt_fnum = prev_alt_fnum;
   }
   if (buf->b_ml.ml_mfp == NULL) {
     // No memfile yet.
     oldbuf = false;
   } else {
     // Existing memfile.
     oldbuf = true;
     set_bufref(&bufref, buf);
     buf_check_timestamp(buf);
     // Check if autocommands made buffer invalid or changed the current
     // buffer.
     if (!bufref_valid(&bufref) || curbuf != old_curbuf.br_buf) {
       goto theend;
     }
     if (aborting()) {
       // Autocmds may abort script processing.
       goto theend;
     }
   }

   // May jump to last used line number for a loaded buffer or when asked
   // for explicitly
   if ((oldbuf && newlnum == ECMD_LASTL) || newlnum == ECMD_LAST) {
     pos_T *pos = &buflist_findfmark(buf)->mark;
     newlnum = pos->lnum;
     solcol = pos->col;
   }

   // Make the (new) buffer the one used by the current window.
   // If the old buffer becomes unused, free it if ECMD_HIDE is false.
   // If the current buffer was empty and has no file name, curbuf
   // is returned by buflist_new(), nothing to do here.
   if (buf != curbuf) {
     // Should only be possible to get here if the cmdwin is closed, or
     // if it's opening and its buffer hasn't been set yet (the new
     // buffer is for it).
     assert(cmdwin_buf == NULL);

     const int save_cmdwin_type = cmdwin_type;
     win_T *const save_cmdwin_win = cmdwin_win;
     win_T *const save_cmdwin_old_curwin = cmdwin_old_curwin;

     // BufLeave applies to the old buffer.
     cmdwin_type = 0;
     cmdwin_win = NULL;
     cmdwin_old_curwin = NULL;

     // Be careful: The autocommands may delete any buffer and change
     // the current buffer.
     // - If the buffer we are going to edit is deleted, give up.
     // - If the current buffer is deleted, prefer to load the new
     //   buffer when loading a buffer is required.  This avoids
     //   loading another buffer which then must be closed again.
     // - If we ended up in the new buffer already, need to skip a few
     //         things, set auto_buf.
     if (buf->b_fname != NULL) {
       new_name = xstrdup(buf->b_fname);
     }
     const bufref_T save_au_new_curbuf = au_new_curbuf;
     set_bufref(&au_new_curbuf, buf);
     apply_autocmds(EVENT_BUFLEAVE, NULL, NULL, false, curbuf);

     cmdwin_type = save_cmdwin_type;
     cmdwin_win = save_cmdwin_win;
     cmdwin_old_curwin = save_cmdwin_old_curwin;

     if (!bufref_valid(&au_new_curbuf)) {
       // New buffer has been deleted.
       delbuf_msg(new_name);  // Frees new_name.
       au_new_curbuf = save_au_new_curbuf;
       goto theend;
     }
     if (aborting()) {             // autocmds may abort script processing
       xfree(new_name);
       au_new_curbuf = save_au_new_curbuf;
       goto theend;
     }
     if (buf == curbuf) {  // already in new buffer
       auto_buf = true;
     } else {
       win_T *the_curwin = curwin;
       buf_T *was_curbuf = curbuf;

       // Set w_locked to avoid that autocommands close the window.
       // Set b_locked for the same reason.
       the_curwin->w_locked = true;
       buf->b_locked++;

       if (curbuf == old_curbuf.br_buf) {
         buf_copy_options(buf, BCO_ENTER);
       }

       // Close the link to the current buffer. This will set
       // oldwin->w_buffer to NULL.
       u_sync(false);
       const bool did_decrement
         = close_buffer(oldwin, curbuf,
                        (flags & ECMD_HIDE)
                        || (curbuf->terminal && terminal_running(curbuf->terminal))
                        ? 0 : DOBUF_UNLOAD,
                        false, false);

       // Autocommands may have closed the window.
       if (win_valid(the_curwin)) {
         the_curwin->w_locked = false;
       }
       buf->b_locked--;

       // autocmds may abort script processing
       if (aborting() && curwin->w_buffer != NULL) {
         xfree(new_name);
         au_new_curbuf = save_au_new_curbuf;
         goto theend;
       }
       // Be careful again, like above.
       if (!bufref_valid(&au_new_curbuf)) {
         // New buffer has been deleted.
         delbuf_msg(new_name);  // Frees new_name.
         au_new_curbuf = save_au_new_curbuf;
         goto theend;
       }
       if (buf == curbuf) {  // already in new buffer
         // close_buffer() has decremented the window count,
         // increment it again here and restore w_buffer.
         if (did_decrement && buf_valid(was_curbuf)) {
           was_curbuf->b_nwindows++;
         }
         if (win_valid_any_tab(oldwin) && oldwin->w_buffer == NULL) {
           oldwin->w_buffer = was_curbuf;
         }
         auto_buf = true;
       } else {
         // <VN> We could instead free the synblock
         // and re-attach to buffer, perhaps.
         if (curwin->w_buffer == NULL
             || curwin->w_s == &(curwin->w_buffer->b_s)) {
           curwin->w_s = &(buf->b_s);
         }

         curwin->w_buffer = buf;
         curbuf = buf;
         curbuf->b_nwindows++;

         // Set 'fileformat', 'binary' and 'fenc' when forced.
         if (!oldbuf && eap != NULL) {
           set_file_options(true, eap);
           set_forced_fenc(eap);
         }
       }

       // May get the window options from the last time this buffer
       // was in this window (or another window).  If not used
       // before, reset the local window options to the global
       // values.  Also restores old folding stuff.
       get_winopts(curbuf);
       did_get_winopts = true;
     }
     xfree(new_name);
     au_new_curbuf = save_au_new_curbuf;
   }

   curwin->w_pcmark.lnum = 1;
   curwin->w_pcmark.col = 0;
 } else {  // !other_file
   if ((flags & (ECMD_ADDBUF | ECMD_ALTBUF)) || check_fname() == FAIL) {
     goto theend;
   }
   oldbuf = (flags & ECMD_OLDBUF);
 }

 // Don't redraw until the cursor is in the right line, otherwise
 // autocommands may cause ml_get errors.
 RedrawingDisabled++;
 did_inc_redrawing_disabled = true;

 buf = curbuf;
 if ((flags & ECMD_SET_HELP) || keep_help_flag) {
   prepare_help_buffer();
 } else if (!curbuf->b_help) {
   // Don't make a buffer listed if it's a help buffer.  Useful when using
   // CTRL-O to go back to a help file.
   set_buflisted(true);
 }

 // If autocommands change buffers under our fingers, forget about
 // editing the file.
 if (buf != curbuf) {
   goto theend;
 }
 if (aborting()) {         // autocmds may abort script processing
   goto theend;
 }

 // Since we are starting to edit a file, consider the filetype to be
 // unset.  Helps for when an autocommand changes files and expects syntax
 // highlighting to work in the other file.
 curbuf->b_did_filetype = false;

 // other_file oldbuf
 //  false     false       re-edit same file, buffer is re-used
 //  false     true        re-edit same file, nothing changes
 //  true      false       start editing new file, new buffer
 //  true      true        start editing in existing buffer (nothing to do)
 if (!other_file && !oldbuf) {         // re-use the buffer
   set_last_cursor(curwin);            // may set b_last_cursor
   if (newlnum == ECMD_LAST || newlnum == ECMD_LASTL) {
     newlnum = curwin->w_cursor.lnum;
     solcol = curwin->w_cursor.col;
   }
   buf = curbuf;
   if (buf->b_fname != NULL) {
     new_name = xstrdup(buf->b_fname);
   } else {
     new_name = NULL;
   }
   set_bufref(&bufref, buf);

   // If the buffer was used before, store the current contents so that
   // the reload can be undone.  Do not do this if the (empty) buffer is
   // being re-used for another file.
   if (!(curbuf->b_flags & BF_NEVERLOADED)
       && (p_ur < 0 || curbuf->b_ml.ml_line_count <= p_ur)) {
     // Sync first so that this is a separate undo-able action.
     u_sync(false);
     if (u_savecommon(curbuf, 0, curbuf->b_ml.ml_line_count + 1, 0, true)
         == FAIL) {
       xfree(new_name);
       goto theend;
     }
     u_unchanged(curbuf);
     buf_freeall(curbuf, BFA_KEEP_UNDO);

     // Tell readfile() not to clear or reload undo info.
     readfile_flags = READ_KEEP_UNDO;
   } else {
     buf_freeall(curbuf, 0);  // Free all things for buffer.
   }
   // If autocommands deleted the buffer we were going to re-edit, give
   // up and jump to the end.
   if (!bufref_valid(&bufref)) {
     delbuf_msg(new_name);  // Frees new_name.
     goto theend;
   }
   xfree(new_name);

   // If autocommands change buffers under our fingers, forget about
   // re-editing the file.  Should do the buf_clear_file(), but perhaps
   // the autocommands changed the buffer...
   if (buf != curbuf) {
     goto theend;
   }
   if (aborting()) {       // autocmds may abort script processing
     goto theend;
   }
   buf_clear_file(curbuf);
   curbuf->b_op_start.lnum = 0;        // clear '[ and '] marks
   curbuf->b_op_end.lnum = 0;
 }

 // If we get here we are sure to start editing

 // Assume success now
 retval = OK;

 // If the file name was changed, reset the not-edit flag so that ":write"
 // works.
 if (!other_file) {
   curbuf->b_flags &= ~BF_NOTEDITED;
 }

 // Check if we are editing the w_arg_idx file in the argument list.
 check_arg_idx(curwin);

 if (!auto_buf) {
   // Set cursor and init window before reading the file and executing
   // autocommands.  This allows for the autocommands to position the
   // cursor.
   curwin_init();

   // It's possible that all lines in the buffer changed.  Need to update
   // automatic folding for all windows where it's used.
   FOR_ALL_TAB_WINDOWS(tp, win) {
     if (win->w_buffer == curbuf) {
       foldUpdateAll(win);
     }
   }

   // Change directories when the 'acd' option is set.
   do_autochdir();

   // Careful: open_buffer() and apply_autocmds() may change the current
   // buffer and window.
   pos_T orig_pos = curwin->w_cursor;
   topline = curwin->w_topline;
   if (!oldbuf) {                          // need to read the file
     swap_exists_action = SEA_DIALOG;
     curbuf->b_flags |= BF_CHECK_RO;       // set/reset 'ro' flag

     // Open the buffer and read the file.
     if (flags & ECMD_NOWINENTER) {
       readfile_flags |= READ_NOWINENTER;
     }
     if (should_abort(open_buffer(false, eap, readfile_flags))) {
       retval = FAIL;
     }

     if (swap_exists_action == SEA_QUIT) {
       retval = FAIL;
     }
     handle_swap_exists(&old_curbuf);
   } else {
     // Read the modelines, but only to set window-local options.  Any
     // buffer-local options have already been set and may have been
     // changed by the user.
     do_modelines(OPT_WINONLY);

     apply_autocmds_retval(EVENT_BUFENTER, NULL, NULL, false, curbuf,
                           &retval);
     if ((flags & ECMD_NOWINENTER) == 0) {
       apply_autocmds_retval(EVENT_BUFWINENTER, NULL, NULL, false, curbuf,
                             &retval);
     }
   }
   check_arg_idx(curwin);

   // If autocommands change the cursor position or topline, we should
   // keep it.  Also when it moves within a line. But not when it moves
   // to the first non-blank.
   if (!equalpos(curwin->w_cursor, orig_pos)) {
     const char *text = get_cursor_line_ptr();

     if (curwin->w_cursor.lnum != orig_pos.lnum
         || curwin->w_cursor.col != (int)(skipwhite(text) - text)) {
       newlnum = curwin->w_cursor.lnum;
       newcol = curwin->w_cursor.col;
     }
   }
   if (curwin->w_topline == topline) {
     topline = 0;
   }

   // Even when cursor didn't move we need to recompute topline.
   changed_line_abv_curs();

   maketitle();
 }

 // Tell the diff stuff that this buffer is new and/or needs updating.
 // Also needed when re-editing the same buffer, because unloading will
 // have removed it as a diff buffer.
 if (curwin->w_p_diff) {
   diff_buf_add(curbuf);
   diff_invalidate(curbuf);
 }

 // If the window options were changed may need to set the spell language.
 // Can only do this after the buffer has been properly setup.
 if (did_get_winopts && curwin->w_p_spell && *curwin->w_s->b_p_spl != NUL) {
   parse_spelllang(curwin);
 }

 if (command == NULL) {
   if (newcol >= 0) {          // position set by autocommands
     curwin->w_cursor.lnum = newlnum;
     curwin->w_cursor.col = newcol;
     check_cursor(curwin);
   } else if (newlnum > 0) {  // line number from caller or old position
     curwin->w_cursor.lnum = newlnum;
     check_cursor_lnum(curwin);
     if (solcol >= 0 && !p_sol) {
       // 'sol' is off: Use last known column.
       curwin->w_cursor.col = solcol;
       check_cursor_col(curwin);
       curwin->w_cursor.coladd = 0;
       curwin->w_set_curswant = true;
     } else {
       beginline(BL_SOL | BL_FIX);
     }
   } else {                  // no line number, go to last line in Ex mode
     if (exmode_active) {
       curwin->w_cursor.lnum = curbuf->b_ml.ml_line_count;
     }
     beginline(BL_WHITE | BL_FIX);
   }
 }

 // Check if cursors in other windows on the same buffer are still valid
 check_lnums(false);

 // Did not read the file, need to show some info about the file.
 // Do this after setting the cursor.
 if (oldbuf
     && !auto_buf) {
   int msg_scroll_save = msg_scroll;

   // Obey the 'O' flag in 'cpoptions': overwrite any previous file
   // message.
   if (shortmess(SHM_OVERALL) && !msg_listdo_overwrite && !exiting && p_verbose == 0) {
     msg_scroll = false;
   }
   if (!msg_scroll) {          // wait a bit when overwriting an error msg
     msg_check_for_delay(false);
   }
   msg_start();
   msg_scroll = msg_scroll_save;
   msg_scrolled_ign = true;

   if (!shortmess(SHM_FILEINFO)) {
     fileinfo(false, true, false);
   }

   msg_scrolled_ign = false;
 }

 curbuf->b_last_used = time(NULL);

 if (command != NULL) {
   do_cmdline(command, NULL, NULL, DOCMD_VERBOSE);
 }

 if (curbuf->b_kmap_state & KEYMAP_INIT) {
   keymap_init();
 }

 RedrawingDisabled--;
 did_inc_redrawing_disabled = false;
 if (!skip_redraw) {
   OptInt n = *so_ptr;
   if (topline == 0 && command == NULL) {
     *so_ptr = 999;    // force cursor to be vertically centered in the window
   }
   update_topline(curwin);
   curwin->w_scbind_pos = plines_m_win_fill(curwin, 1, curwin->w_topline);
   *so_ptr = n;
   redraw_curbuf_later(UPD_NOT_VALID);  // redraw this buffer later
 }

 // Change directories when the 'acd' option is set.
 do_autochdir();

theend:
 if (bufref_valid(&old_curbuf) && old_curbuf.br_buf->terminal != NULL) {
   terminal_check_size(old_curbuf.br_buf->terminal);
 }
 if ((!bufref_valid(&old_curbuf) || curbuf != old_curbuf.br_buf) && curbuf->terminal != NULL) {
   terminal_check_size(curbuf->terminal);
 }

 if (did_inc_redrawing_disabled) {
   RedrawingDisabled--;
 }
 if (did_set_swapcommand) {
   set_vim_var_string(VV_SWAPCOMMAND, NULL, -1);
 }
 xfree(free_fname);
 return retval;
}

static void delbuf_msg(char *name)
{
 semsg(_("E143: Autocommands unexpectedly deleted new buffer %s"),
       name == NULL ? "" : name);
 xfree(name);
 au_new_curbuf.br_buf = NULL;
 au_new_curbuf.br_buf_free_count = 0;
}

static int append_indent = 0;       // autoindent for first line

/// ":insert" and ":append", also used by ":change"
void ex_append(exarg_T *eap)
{
 char *theline;
 bool did_undo = false;
 linenr_T lnum = eap->line2;
 int indent = 0;
 char *p;
 bool empty = (curbuf->b_ml.ml_flags & ML_EMPTY);

 // the ! flag toggles autoindent
 if (eap->forceit) {
   curbuf->b_p_ai = !curbuf->b_p_ai;
 }

 // First autoindent comes from the line we start on
 if (eap->cmdidx != CMD_change && curbuf->b_p_ai && lnum > 0) {
   append_indent = get_indent_lnum(lnum);
 }

 if (eap->cmdidx != CMD_append) {
   lnum--;
 }

 // when the buffer is empty need to delete the dummy line
 if (empty && lnum == 1) {
   lnum = 0;
 }

 State = MODE_INSERT;                   // behave like in Insert mode
 if (curbuf->b_p_iminsert == B_IMODE_LMAP) {
   State |= MODE_LANGMAP;
 }

 while (true) {
   msg_scroll = true;
   need_wait_return = false;
   if (curbuf->b_p_ai) {
     if (append_indent >= 0) {
       indent = append_indent;
       append_indent = -1;
     } else if (lnum > 0) {
       indent = get_indent_lnum(lnum);
     }
   }
   if (*eap->arg == '|') {
     // Get the text after the trailing bar.
     theline = xstrdup(eap->arg + 1);
     *eap->arg = NUL;
   } else if (eap->ea_getline == NULL) {
     // No getline() function, use the lines that follow. This ends
     // when there is no more.
     if (eap->nextcmd == NULL) {
       break;
     }
     p = vim_strchr(eap->nextcmd, NL);
     if (p == NULL) {
       p = eap->nextcmd + strlen(eap->nextcmd);
     }
     theline = xmemdupz(eap->nextcmd, (size_t)(p - eap->nextcmd));
     if (*p != NUL) {
       p++;
     } else {
       p = NULL;
     }
     eap->nextcmd = p;
   } else {
     int save_State = State;
     // Set State to avoid the cursor shape to be set to MODE_INSERT
     // state when getline() returns.
     State = MODE_CMDLINE;
     theline = eap->ea_getline(eap->cstack->cs_looplevel > 0 ? -1 : NUL,
                               eap->cookie, indent, true);
     State = save_State;
   }
   lines_left = Rows - 1;
   if (theline == NULL) {
     break;
   }

   // Look for the "." after automatic indent.
   int vcol = 0;
   for (p = theline; indent > vcol; p++) {
     if (*p == ' ') {
       vcol++;
     } else if (*p == TAB) {
       vcol += 8 - vcol % 8;
     } else {
       break;
     }
   }
   if ((p[0] == '.' && p[1] == NUL)
       || (!did_undo && u_save(lnum, lnum + 1 + (empty ? 1 : 0))
           == FAIL)) {
     xfree(theline);
     break;
   }

   // don't use autoindent if nothing was typed.
   if (p[0] == NUL) {
     theline[0] = NUL;
   }

   did_undo = true;
   ml_append(lnum, theline, 0, false);
   if (empty) {
     // there are no marks below the inserted lines
     appended_lines(lnum, 1);
   } else {
     appended_lines_mark(lnum, 1);
   }

   xfree(theline);
   lnum++;

   if (empty) {
     ml_delete(2);
     empty = false;
   }
 }
 State = MODE_NORMAL;
 ui_cursor_shape();

 if (eap->forceit) {
   curbuf->b_p_ai = !curbuf->b_p_ai;
 }

 // "start" is set to eap->line2+1 unless that position is invalid (when
 // eap->line2 pointed to the end of the buffer and nothing was appended)
 // "end" is set to lnum when something has been appended, otherwise
 // it is the same as "start"  -- Acevedo
 if ((cmdmod.cmod_flags & CMOD_LOCKMARKS) == 0) {
   curbuf->b_op_start.lnum
     = (eap->line2 < curbuf->b_ml.ml_line_count) ? eap->line2 + 1 : curbuf->b_ml.ml_line_count;
   if (eap->cmdidx != CMD_append) {
     curbuf->b_op_start.lnum--;
   }
   curbuf->b_op_end.lnum = (eap->line2 < lnum) ? lnum : curbuf->b_op_start.lnum;
   curbuf->b_op_start.col = curbuf->b_op_end.col = 0;
 }
 curwin->w_cursor.lnum = lnum;
 check_cursor_lnum(curwin);
 beginline(BL_SOL | BL_FIX);

 need_wait_return = false;     // don't use wait_return() now
 ex_no_reprint = true;
}

/// ":change"
void ex_change(exarg_T *eap)
{
 linenr_T lnum;

 if (eap->line2 >= eap->line1
     && u_save(eap->line1 - 1, eap->line2 + 1) == FAIL) {
   return;
 }

 // the ! flag toggles autoindent
 if (eap->forceit ? !curbuf->b_p_ai : curbuf->b_p_ai) {
   append_indent = get_indent_lnum(eap->line1);
 }

 for (lnum = eap->line2; lnum >= eap->line1; lnum--) {
   if (curbuf->b_ml.ml_flags & ML_EMPTY) {         // nothing to delete
     break;
   }
   ml_delete(eap->line1);
 }

 // make sure the cursor is not beyond the end of the file now
 check_cursor_lnum(curwin);
 deleted_lines_mark(eap->line1, (eap->line2 - lnum));

 // ":append" on the line above the deleted lines.
 eap->line2 = eap->line1;
 ex_append(eap);
}

void ex_z(exarg_T *eap)
{
 int64_t bigness;
 int minus = 0;
 linenr_T start, end, curs;
 linenr_T lnum = eap->line2;

 // Vi compatible: ":z!" uses display height, without a count uses
 // 'scroll'
 if (eap->forceit) {
   bigness = Rows - 1;
 } else if (ONE_WINDOW) {
   bigness = curwin->w_p_scr * 2;
 } else {
   bigness = curwin->w_view_height - 3;
 }
 bigness = MAX(bigness, 1);

 char *x = eap->arg;
 char *kind = x;
 if (*kind == '-' || *kind == '+' || *kind == '='
     || *kind == '^' || *kind == '.') {
   x++;
 }
 while (*x == '-' || *x == '+') {
   x++;
 }

 if (*x != 0) {
   if (!ascii_isdigit(*x)) {
     emsg(_(e_non_numeric_argument_to_z));
     return;
   }
   bigness = atol(x);

   // bigness could be < 0 if atol(x) overflows.
   if (bigness > 2 * curbuf->b_ml.ml_line_count || bigness < 0) {
     bigness = 2 * curbuf->b_ml.ml_line_count;
   }

   p_window = (int)bigness;
   if (*kind == '=') {
     bigness += 2;
   }
 }

 // the number of '-' and '+' multiplies the distance
 if (*kind == '-' || *kind == '+') {
   for (x = kind + 1; *x == *kind; x++) {}
 }

 switch (*kind) {
 case '-':
   start = lnum - (linenr_T)bigness * (linenr_T)(x - kind) + 1;
   end = start + (linenr_T)bigness - 1;
   curs = end;
   break;

 case '=':
   start = lnum - ((linenr_T)bigness + 1) / 2 + 1;
   end = lnum + ((linenr_T)bigness + 1) / 2 - 1;
   curs = lnum;
   minus = 1;
   break;

 case '^':
   start = lnum - (linenr_T)bigness * 2;
   end = lnum - (linenr_T)bigness;
   curs = lnum - (linenr_T)bigness;
   break;

 case '.':
   start = lnum - ((linenr_T)bigness + 1) / 2 + 1;
   end = lnum + ((linenr_T)bigness + 1) / 2 - 1;
   curs = end;
   break;

 default:        // '+'
   start = lnum;
   if (*kind == '+') {
     start += (linenr_T)bigness * (linenr_T)(x - kind - 1) + 1;
   } else if (eap->addr_count == 0) {
     start++;
   }
   end = start + (linenr_T)bigness - 1;
   curs = end;
   break;
 }

 start = MAX(start, 1);
 end = MIN(end, curbuf->b_ml.ml_line_count);
 curs = MIN(MAX(curs, 1), curbuf->b_ml.ml_line_count);

 for (linenr_T i = start; i <= end; i++) {
   if (minus && i == lnum) {
     msg_putchar('\n');

     for (int j = 1; j < Columns; j++) {
       msg_putchar('-');
     }
   }

   print_line(i, eap->flags & EXFLAG_NR, eap->flags & EXFLAG_LIST, i == start);

   if (minus && i == lnum) {
     msg_putchar('\n');

     for (int j = 1; j < Columns; j++) {
       msg_putchar('-');
     }
   }
 }

 if (curwin->w_cursor.lnum != curs) {
   curwin->w_cursor.lnum = curs;
   curwin->w_cursor.col = 0;
 }
 ex_no_reprint = true;
}

/// @return  true if the secure flag is set and also give an error message.
///          Otherwise, return false.
bool check_secure(void)
{
 if (secure) {
   secure = 2;
   emsg(_(e_curdir));
   return true;
 }

 // In the sandbox more things are not allowed, including the things
 // disallowed in secure mode.
 if (sandbox != 0) {
   emsg(_(e_sandbox));
   return true;
 }
 return false;
}

/// Previous substitute replacement string
static SubReplacementString old_sub = { NULL, 0, NULL };

static int global_need_beginline;       // call beginline() after ":g"

/// Get old substitute replacement string
///
/// @param[out]  ret_sub    Location where old string will be saved.
void sub_get_replacement(SubReplacementString *const ret_sub)
 FUNC_ATTR_NONNULL_ALL
{
 *ret_sub = old_sub;
}

/// Set substitute string and timestamp
///
/// @warning `sub` must be in allocated memory. It is not copied.
///
/// @param[in]  sub  New replacement string.
void sub_set_replacement(SubReplacementString sub)
{
 xfree(old_sub.sub);
 if (sub.additional_data != old_sub.additional_data) {
   xfree(old_sub.additional_data);
 }
 old_sub = sub;
}

/// Recognize ":%s/\n//" and turn it into a join command, which is much
/// more efficient.
///
/// @param[in]  eap  Ex arguments
/// @param[in]  pat  Search pattern
/// @param[in]  sub  Replacement string
/// @param[in]  cmd  Command from :s_flags
/// @param[in]  save Save pattern to options, history
///
/// @returns true if :substitute can be replaced with a join command
static bool sub_joining_lines(exarg_T *eap, char *pat, size_t patlen, const char *sub,
                             const char *cmd, bool save, bool keeppatterns)
 FUNC_ATTR_NONNULL_ARG(1, 4, 5)
{
 // TODO(vim): find a generic solution to make line-joining operations more
 // efficient, avoid allocating a string that grows in size.
 if (pat != NULL
     && strcmp(pat, "\\n") == 0
     && *sub == NUL
     && (*cmd == NUL || (cmd[1] == NUL
                         && (*cmd == 'g'
                             || *cmd == 'l'
                             || *cmd == 'p'
                             || *cmd == '#')))) {
   if (eap->skip) {
     return true;
   }
   curwin->w_cursor.lnum = eap->line1;
   if (*cmd == 'l') {
     eap->flags = EXFLAG_LIST;
   } else if (*cmd == '#') {
     eap->flags = EXFLAG_NR;
   } else if (*cmd == 'p') {
     eap->flags = EXFLAG_PRINT;
   }

   // The number of lines joined is the number of lines in the range
   linenr_T joined_lines_count = eap->line2 - eap->line1 + 1
                                 // plus one extra line if not at the end of file.
                                 + (eap->line2 < curbuf->b_ml.ml_line_count ? 1 : 0);
   if (joined_lines_count > 1) {
     do_join((size_t)joined_lines_count, false, true, false, true);
     sub_nsubs = joined_lines_count - 1;
     sub_nlines = 1;
     do_sub_msg(false);
     ex_may_print(eap);
   }

   if (save) {
     if (!keeppatterns) {
       save_re_pat(RE_SUBST, pat, patlen, magic_isset());
     }
     // put pattern in history
     add_to_history(HIST_SEARCH, pat, patlen, true, NUL);
   }

   return true;
 }

 return false;
}

/// Allocate memory to store the replacement text for :substitute.
///
/// Slightly more memory that is strictly necessary is allocated to reduce the
/// frequency of memory (re)allocation.
///
/// @param[in,out]  new_start      pointer to the memory for the replacement text
/// @param[in,out]  new_start_len  pointer to length of new_start
/// @param[in]      needed_len     amount of memory needed
///
/// @returns pointer to the end of the allocated memory
static char *sub_grow_buf(char **new_start, int *new_start_len, int needed_len)
 FUNC_ATTR_NONNULL_ALL FUNC_ATTR_NONNULL_RET
{
 char *new_end;
 if (*new_start == NULL) {
   // Get some space for a temporary buffer to do the
   // substitution into (and some extra space to avoid
   // too many calls to xmalloc()/free()).
   *new_start_len = needed_len + 50;
   *new_start = xcalloc(1, (size_t)(*new_start_len));
   **new_start = NUL;
   new_end = *new_start;
 } else {
   // Check if the temporary buffer is long enough to do the
   // substitution into.  If not, make it larger (with a bit
   // extra to avoid too many calls to xmalloc()/free()).
   size_t len = strlen(*new_start);
   needed_len += (int)len;
   if (needed_len > *new_start_len) {
     size_t prev_new_start_len = (size_t)(*new_start_len);
     *new_start_len = needed_len + 50;
     size_t added_len = (size_t)(*new_start_len) - prev_new_start_len;
     *new_start = xrealloc(*new_start, (size_t)(*new_start_len));
     memset(*new_start + prev_new_start_len, 0, added_len);
   }
   new_end = *new_start + len;
 }

 return new_end;
}

/// Parse cmd string for :substitute's {flags} and update subflags accordingly
///
/// @param[in]      cmd  command string
/// @param[in,out]  subflags  current flags defined for the :substitute command
/// @param[in,out]  which_pat  pattern type from which to get default search
///
/// @returns pointer to the end of the flags, which may be the end of the string
static char *sub_parse_flags(char *cmd, subflags_T *subflags, int *which_pat)
 FUNC_ATTR_NONNULL_ALL FUNC_ATTR_NONNULL_RET
{
 // Find trailing options.  When '&' is used, keep old options.
 if (*cmd == '&') {
   cmd++;
 } else {
   subflags->do_all = p_gd;
   subflags->do_ask = false;
   subflags->do_error = true;
   subflags->do_print = false;
   subflags->do_list = false;
   subflags->do_count = false;
   subflags->do_number = false;
   subflags->do_ic = kSubHonorOptions;
 }
 while (*cmd) {
   // Note that 'g' and 'c' are always inverted.
   // 'r' is never inverted.
   if (*cmd == 'g') {
     subflags->do_all = !subflags->do_all;
   } else if (*cmd == 'c') {
     subflags->do_ask = !subflags->do_ask;
   } else if (*cmd == 'n') {
     subflags->do_count = true;
   } else if (*cmd == 'e') {
     subflags->do_error = !subflags->do_error;
   } else if (*cmd == 'r') {  // use last used regexp
     *which_pat = RE_LAST;
   } else if (*cmd == 'p') {
     subflags->do_print = true;
   } else if (*cmd == '#') {
     subflags->do_print = true;
     subflags->do_number = true;
   } else if (*cmd == 'l') {
     subflags->do_print = true;
     subflags->do_list = true;
   } else if (*cmd == 'i') {  // ignore case
     subflags->do_ic = kSubIgnoreCase;
   } else if (*cmd == 'I') {  // don't ignore case
     subflags->do_ic = kSubMatchCase;
   } else {
     break;
   }
   cmd++;
 }
 if (subflags->do_count) {
   subflags->do_ask = false;
 }

 return cmd;
}

/// Skip over the "sub" part in :s/pat/sub/ where "delimiter" is the separating
/// character.
static char *skip_substitute(char *start, int delimiter)
{
 char *p = start;

 while (p[0]) {
   if (p[0] == delimiter) {  // end delimiter found
     *p++ = NUL;  // replace it with a NUL
     break;
   }
   if (p[0] == '\\' && p[1] != 0) {  // skip escaped characters
     p++;
   }
   MB_PTR_ADV(p);
 }
 return p;
}

static int check_regexp_delim(int c)
 FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT
{
 if (isalpha(c)) {
   emsg(_("E146: Regular expressions can't be delimited by letters"));
   return FAIL;
 }
 return OK;
}

/// Perform a substitution from line eap->line1 to line eap->line2 using the
/// command pointed to by eap->arg which should be of the form:
///
/// /pattern/substitution/{flags}
///
/// The usual escapes are supported as described in the regexp docs.
///
/// @param cmdpreview_ns  The namespace to show 'inccommand' preview highlights.
///                       If <= 0, preview shouldn't be shown.
/// @return  0, 1 or 2. See cmdpreview_may_show() for more information on the meaning.
static int do_sub(exarg_T *eap, const proftime_T timeout, const int cmdpreview_ns,
                 const handle_T cmdpreview_bufnr)
{
#define ADJUST_SUB_FIRSTLNUM() \
 do { \
   /* For a multi-line match, make a copy of the last matched */ \
   /* line and continue in that one. */ \
   if (nmatch > 1) { \
     sub_firstlnum += (linenr_T)nmatch - 1; \
     xfree(sub_firstline); \
     sub_firstline = xstrnsave(ml_get(sub_firstlnum), \
                               (size_t)ml_get_len(sub_firstlnum)); \
     /* When going beyond the last line, stop substituting. */ \
     if (sub_firstlnum <= line2) { \
       do_again = true; \
     } else { \
       subflags.do_all = false; \
     } \
   } \
   if (skip_match) { \
     /* Already hit end of the buffer, sub_firstlnum is one */ \
     /* less than what it ought to be. */ \
     xfree(sub_firstline); \
     sub_firstline = xstrdup(""); \
     copycol = 0; \
   } \
 } while (0)

 int i = 0;
 regmmatch_T regmatch;
 static subflags_T subflags = {
   .do_all = false,
   .do_ask = false,
   .do_count = false,
   .do_error = true,
   .do_print = false,
   .do_list = false,
   .do_number = false,
   .do_ic = kSubHonorOptions
 };
 char *pat = NULL;
 char *sub = NULL;  // init for GCC
 size_t patlen = 0;
 int delimiter;
 bool has_second_delim = false;
 int sublen;
 bool got_quit = false;
 bool got_match = false;
 int which_pat;
 char *cmd = eap->arg;
 linenr_T first_line = 0;  // first changed line
 linenr_T last_line = 0;    // below last changed line AFTER the change
 linenr_T old_line_count = curbuf->b_ml.ml_line_count;
 char *sub_firstline;    // allocated copy of first sub line
 bool endcolumn = false;   // cursor in last column when done
 const bool keeppatterns = cmdmod.cmod_flags & CMOD_KEEPPATTERNS;
 PreviewLines preview_lines = { KV_INITIAL_VALUE, 0 };
 static int pre_hl_id = 0;
 pos_T old_cursor = curwin->w_cursor;
 int start_nsubs;

 bool did_save = false;

 if (!global_busy) {
   sub_nsubs = 0;
   sub_nlines = 0;
 }
 start_nsubs = sub_nsubs;

 if (eap->cmdidx == CMD_tilde) {
   which_pat = RE_LAST;        // use last used regexp
 } else {
   which_pat = RE_SUBST;       // use last substitute regexp
 }
 // new pattern and substitution
 if (eap->cmd[0] == 's' && *cmd != NUL && !ascii_iswhite(*cmd)
     && vim_strchr("0123456789cegriIp|\"", (uint8_t)(*cmd)) == NULL) {
   // don't accept alphanumeric for separator
   if (check_regexp_delim(*cmd) == FAIL) {
     return 0;
   }

   // undocumented vi feature:
   //  "\/sub/" and "\?sub?" use last used search pattern (almost like
   //  //sub/r).  "\&sub&" use last substitute pattern (like //sub/).
   if (*cmd == '\\') {
     cmd++;
     if (vim_strchr("/?&", (uint8_t)(*cmd)) == NULL) {
       emsg(_(e_backslash));
       return 0;
     }
     if (*cmd != '&') {
       which_pat = RE_SEARCH;              // use last '/' pattern
     }
     pat = "";                   // empty search pattern
     patlen = 0;
     delimiter = (uint8_t)(*cmd++);                   // remember delimiter character
     has_second_delim = true;
   } else {          // find the end of the regexp
     which_pat = RE_LAST;                  // use last used regexp
     delimiter = (uint8_t)(*cmd++);                   // remember delimiter character
     pat = cmd;                            // remember start of search pat
     cmd = skip_regexp_ex(cmd, delimiter, magic_isset(), &eap->arg, NULL, NULL);
     if (cmd[0] == delimiter) {            // end delimiter found
       *cmd++ = NUL;                       // replace it with a NUL
       has_second_delim = true;
     }
     patlen = strlen(pat);
   }

   // Small incompatibility: vi sees '\n' as end of the command, but in
   // Vim we want to use '\n' to find/substitute a NUL.
   char *p = cmd;  // remember the start of the substitution
   cmd = skip_substitute(cmd, delimiter);
   sub = xstrdup(p);

   if (!eap->skip && !keeppatterns && cmdpreview_ns <= 0) {
     sub_set_replacement((SubReplacementString) {
       .sub = xstrdup(sub),
       .timestamp = os_time(),
       .additional_data = NULL,
     });
   }
 } else if (!eap->skip) {    // use previous pattern and substitution
   if (old_sub.sub == NULL) {      // there is no previous command
     emsg(_(e_nopresub));
     return 0;
   }
   pat = NULL;                 // search_regcomp() will use previous pattern
   patlen = 0;
   sub = xstrdup(old_sub.sub);

   // Vi compatibility quirk: repeating with ":s" keeps the cursor in the
   // last column after using "$".
   endcolumn = (curwin->w_curswant == MAXCOL);
 }

 if (sub != NULL && sub_joining_lines(eap, pat, patlen, sub, cmd, cmdpreview_ns <= 0,
                                      keeppatterns)) {
   xfree(sub);
   return 0;
 }

 cmd = sub_parse_flags(cmd, &subflags, &which_pat);

 bool save_do_all = subflags.do_all;  // remember user specified 'g' flag
 bool save_do_ask = subflags.do_ask;  // remember user specified 'c' flag

 // check for a trailing count
 cmd = skipwhite(cmd);
 if (ascii_isdigit(*cmd)) {
   i = getdigits_int(&cmd, true, INT_MAX);
   if (i <= 0 && !eap->skip && subflags.do_error) {
     emsg(_(e_zerocount));
     xfree(sub);
     return 0;
   } else if (i >= INT_MAX) {
     char buf[20];
     vim_snprintf(buf, sizeof(buf), "%d", i);
     semsg(_(e_val_too_large), buf);
     xfree(sub);
     return 0;
   }
   eap->line1 = eap->line2;
   eap->line2 += (linenr_T)i - 1;
   eap->line2 = MIN(eap->line2, curbuf->b_ml.ml_line_count);
 }

 // check for trailing command or garbage
 cmd = skipwhite(cmd);
 if (*cmd && *cmd != '"') {        // if not end-of-line or comment
   eap->nextcmd = check_nextcmd(cmd);
   if (eap->nextcmd == NULL) {
     semsg(_(e_trailing_arg), cmd);
     xfree(sub);
     return 0;
   }
 }

 if (eap->skip) {          // not executing commands, only parsing
   xfree(sub);
   return 0;
 }

 if (!subflags.do_count && !MODIFIABLE(curbuf)) {
   // Substitution is not allowed in non-'modifiable' buffer
   emsg(_(e_modifiable));
   xfree(sub);
   return 0;
 }

 if (search_regcomp(pat, patlen, NULL, RE_SUBST, which_pat,
                    (cmdpreview_ns > 0 ? 0 : SEARCH_HIS), &regmatch) == FAIL) {
   if (subflags.do_error) {
     emsg(_(e_invcmd));
   }
   xfree(sub);
   return 0;
 }

 // the 'i' or 'I' flag overrules 'ignorecase' and 'smartcase'
 if (subflags.do_ic == kSubIgnoreCase) {
   regmatch.rmm_ic = true;
 } else if (subflags.do_ic == kSubMatchCase) {
   regmatch.rmm_ic = false;
 }

 sub_firstline = NULL;

 assert(sub != NULL);

 // If the substitute pattern starts with "\=" then it's an expression.
 // Make a copy, a recursive function may free it.
 // Otherwise, '~' in the substitute pattern is replaced with the old
 // pattern.  We do it here once to avoid it to be replaced over and over
 // again.
 if (sub[0] == '\\' && sub[1] == '=') {
   char *p = xstrdup(sub);
   xfree(sub);
   sub = p;
 } else {
   char *p = regtilde(sub, magic_isset(), cmdpreview_ns > 0);
   if (p != sub) {
     xfree(sub);
     sub = p;
   }
 }

 // Check for a match on each line.
 // If preview: limit to max('cmdwinheight', viewport).
 linenr_T line2 = eap->line2;

 for (linenr_T lnum = eap->line1;
      lnum <= line2 && !got_quit && !aborting()
      && (cmdpreview_ns <= 0 || preview_lines.lines_needed <= (linenr_T)p_cwh
          || lnum <= curwin->w_botline);
      lnum++) {
   int nmatch = vim_regexec_multi(&regmatch, curwin, curbuf, lnum,
                                  0, NULL, NULL);
   if (nmatch) {
     colnr_T copycol;
     colnr_T matchcol;
     colnr_T prev_matchcol = MAXCOL;
     char *new_end;
     char *new_start = NULL;
     int new_start_len = 0;
     char *p1;
     bool did_sub = false;
     int lastone;
     linenr_T nmatch_tl = 0;               // nr of lines matched below lnum
     int do_again;                     // do it again after joining lines
     bool skip_match = false;
     linenr_T sub_firstlnum;           // nr of first sub line

     // Track where substitutions started (set once per line).
     linenr_T lnum_start = 0;

     // Track per-line data for each match.
     // Will be sent as a batch to `extmark_splice` after the substitution is done.
     typedef struct {
       int start_col;         // Position in new text where replacement goes
       lpos_T start;          // Match start position in original text
       lpos_T end;            // Match end position in original text
       int matchcols;         // Columns deleted from original text
       bcount_t matchbytes;   // Bytes deleted from original text
       int subcols;           // Columns in replacement text
       bcount_t subbytes;     // Bytes in replacement text
       linenr_T lnum_before;  // Line number before this substitution
       linenr_T lnum_after;   // Line number after this substitution
     } LineData;

     kvec_t(LineData) line_matches = KV_INITIAL_VALUE;

     // The new text is build up step by step, to avoid too much
     // copying.  There are these pieces:
     // sub_firstline  The old text, unmodified.
     // copycol                Column in the old text where we started
     //                        looking for a match; from here old text still
     //                        needs to be copied to the new text.
     // matchcol               Column number of the old text where to look
     //                        for the next match.  It's just after the
     //                        previous match or one further.
     // prev_matchcol  Column just after the previous match (if any).
     //                        Mostly equal to matchcol, except for the first
     //                        match and after skipping an empty match.
     // regmatch.*pos  Where the pattern matched in the old text.
     // new_start      The new text, all that has been produced so
     //                        far.
     // new_end                The new text, where to append new text.
     //
     // lnum           The line number where we found the start of
     //                        the match.  Can be below the line we searched
     //                        when there is a \n before a \zs in the
     //                        pattern.
     // sub_firstlnum  The line number in the buffer where to look
     //                        for a match.  Can be different from "lnum"
     //                        when the pattern or substitute string contains
     //                        line breaks.
     //
     // Special situations:
     // - When the substitute string contains a line break, the part up
     //   to the line break is inserted in the text, but the copy of
     //   the original line is kept.  "sub_firstlnum" is adjusted for
     //   the inserted lines.
     // - When the matched pattern contains a line break, the old line
     //   is taken from the line at the end of the pattern.  The lines
     //   in the match are deleted later, "sub_firstlnum" is adjusted
     //   accordingly.
     //
     // The new text is built up in new_start[].  It has some extra
     // room to avoid using xmalloc()/free() too often.  new_start_len is
     // the length of the allocated memory at new_start.
     //
     // Make a copy of the old line, so it won't be taken away when
     // updating the screen or handling a multi-line match.  The "old_"
     // pointers point into this copy.
     sub_firstlnum = lnum;
     copycol = 0;
     matchcol = 0;

     // At first match, remember current cursor position.
     if (!got_match) {
       setpcmark();
       got_match = true;
     }

     // Loop until nothing more to replace in this line.
     // 1. Handle match with empty string.
     // 2. If subflags.do_ask is set, ask for confirmation.
     // 3. substitute the string.
     // 4. if subflags.do_all is set, find next match
     // 5. break if there isn't another match in this line
     while (true) {
       SubResult current_match = {
         .start = { 0, 0 },
         .end = { 0, 0 },
         .pre_match = 0,
       };
       // lnum is where the match start, but maybe not the pattern match,
       // since we can have \n before \zs in the pattern

       // Advance "lnum" to the line where the match starts.  The
       // match does not start in the first line when there is a line
       // break before \zs.
       if (regmatch.startpos[0].lnum > 0) {
         current_match.pre_match = lnum;
         lnum += regmatch.startpos[0].lnum;
         sub_firstlnum += regmatch.startpos[0].lnum;
         nmatch -= regmatch.startpos[0].lnum;
         XFREE_CLEAR(sub_firstline);
       }

       // Now we're at the line where the pattern match starts
       // Note: If not first match on a line, column can't be known here
       current_match.start.lnum = sub_firstlnum;

       // Match might be after the last line for "\n\zs" matching at
       // the end of the last line.
       if (lnum > curbuf->b_ml.ml_line_count) {
         break;
       }
       if (sub_firstline == NULL) {
         sub_firstline = xstrnsave(ml_get(sub_firstlnum),
                                   (size_t)ml_get_len(sub_firstlnum));
       }

       // Save the line number of the last change for the final
       // cursor position (just like Vi).
       curwin->w_cursor.lnum = lnum;
       do_again = false;

       // 1. Match empty string does not count, except for first
       // match.  This reproduces the strange vi behaviour.
       // This also catches endless loops.
       if (matchcol == prev_matchcol
           && regmatch.endpos[0].lnum == 0
           && matchcol == regmatch.endpos[0].col) {
         if (sub_firstline[matchcol] == NUL) {
           // We already were at the end of the line.  Don't look
           // for a match in this line again.
           skip_match = true;
         } else {
           // search for a match at next column
           matchcol += utfc_ptr2len(sub_firstline + matchcol);
         }
         // match will be pushed to preview_lines, bring it into a proper state
         current_match.start.col = matchcol;
         current_match.end.lnum = sub_firstlnum;
         current_match.end.col = matchcol;
         goto skip;
       }

       // Normally we continue searching for a match just after the
       // previous match.
       matchcol = regmatch.endpos[0].col;
       prev_matchcol = matchcol;

       // 2. If subflags.do_count is set only increase the counter.
       //    If do_ask is set, ask for confirmation.
       if (subflags.do_count) {
         // For a multi-line match, put matchcol at the NUL at
         // the end of the line and set nmatch to one, so that
         // we continue looking for a match on the next line.
         // Avoids that ":s/\nB\@=//gc" get stuck.
         if (nmatch > 1) {
           matchcol = (colnr_T)strlen(sub_firstline);
           nmatch = 1;
           skip_match = true;
         }
         sub_nsubs++;
         did_sub = true;
         // Skip the substitution, unless an expression is used,
         // then it is evaluated in the sandbox.
         if (!(sub[0] == '\\' && sub[1] == '=')) {
           goto skip;
         }
       }

       if (subflags.do_ask && cmdpreview_ns <= 0) {
         int typed = 0;
         int save_State = State;
         curwin->w_cursor.col = regmatch.startpos[0].col;

         if (curwin->w_p_crb) {
           do_check_cursorbind();
         }

         // When 'cpoptions' contains "u" don't sync undo when
         // asking for confirmation.
         if (vim_strchr(p_cpo, CPO_UNDO) != NULL) {
           no_u_sync++;
         }

         // Loop until 'y', 'n', 'q', CTRL-E or CTRL-Y typed.
         while (subflags.do_ask) {
           if (exmode_active) {
             print_line_no_prefix(lnum, subflags.do_number, subflags.do_list);

             colnr_T sc, ec;
             getvcol(curwin, &curwin->w_cursor, &sc, NULL, NULL);
             curwin->w_cursor.col = MAX(regmatch.endpos[0].col - 1, 0);

             getvcol(curwin, &curwin->w_cursor, NULL, NULL, &ec);
             curwin->w_cursor.col = regmatch.startpos[0].col;
             if (subflags.do_number || curwin->w_p_nu) {
               int numw = number_width(curwin) + 1;
               sc += numw;
               ec += numw;
             }

             char *prompt = xmallocz((size_t)ec + 1);
             memset(prompt, ' ', (size_t)sc);
             memset(prompt + sc, '^', (size_t)(ec - sc) + 1);
             char *resp = getcmdline_prompt(-1, prompt, 0, EXPAND_NOTHING, NULL,
                                            CALLBACK_NONE, false, NULL);
             if (!ui_has(kUIMessages)) {
               msg_putchar('\n');
             }
             xfree(prompt);
             if (resp != NULL) {
               typed = (uint8_t)(*resp);
               xfree(resp);
             } else {
               // getcmdline_prompt() returns NULL if there is no command line to return.
               typed = NUL;
             }
             // When ":normal" runs out of characters we get
             // an empty line.  Use "q" to get out of the
             // loop.
             if (ex_normal_busy && typed == NUL) {
               typed = 'q';
             }
           } else {
             char *orig_line = NULL;
             int len_change = 0;
             const bool save_p_lz = p_lz;
             int save_p_fen = curwin->w_p_fen;

             curwin->w_p_fen = false;
             // Invert the matched string.
             // Remove the inversion afterwards.
             int temp = RedrawingDisabled;
             RedrawingDisabled = 0;

             // avoid calling update_screen() in vgetorpeek()
             p_lz = false;

             if (new_start != NULL) {
               // There already was a substitution, we would
               // like to show this to the user.  We cannot
               // really update the line, it would change
               // what matches.  Temporarily replace the line
               // and change it back afterwards.
               orig_line = xstrnsave(ml_get(lnum), (size_t)ml_get_len(lnum));
               char *new_line = concat_str(new_start, sub_firstline + copycol);

               // Position the cursor relative to the end of the line, the
               // previous substitute may have inserted or deleted characters
               // before the cursor.
               len_change = (int)strlen(new_line) - (int)strlen(orig_line);
               curwin->w_cursor.col += len_change;
               ml_replace(lnum, new_line, false);
             }

             search_match_lines = regmatch.endpos[0].lnum
                                  - regmatch.startpos[0].lnum;
             search_match_endcol = regmatch.endpos[0].col
                                   + len_change;
             if (search_match_lines == 0 && search_match_endcol == 0) {
               // highlight at least one character for /^/
               search_match_endcol = 1;
             }
             highlight_match = true;

             update_topline(curwin);
             validate_cursor(curwin);
             redraw_later(curwin, UPD_SOME_VALID);
             show_cursor_info_later(true);
             update_screen();
             redraw_later(curwin, UPD_SOME_VALID);

             curwin->w_p_fen = save_p_fen;

             char *p = _("replace with %s? (y)es/(n)o/(a)ll/(q)uit/(l)ast/scroll up(^E)/down(^Y)");
             snprintf(IObuff, IOSIZE, p, sub);
             p = xstrdup(IObuff);
             typed = prompt_for_input(p, HLF_R, true, NULL);
             highlight_match = false;
             xfree(p);

             msg_didout = false;                 // don't scroll up
             gotocmdline(true);
             p_lz = save_p_lz;
             RedrawingDisabled = temp;

             // restore the line
             if (orig_line != NULL) {
               ml_replace(lnum, orig_line, false);
             }
           }

           need_wait_return = false;             // no hit-return prompt
           if (typed == 'q' || typed == ESC || typed == Ctrl_C) {
             got_quit = true;
             break;
           }
           if (typed == 'n') {
             break;
           }
           if (typed == 'y') {
             break;
           }
           if (typed == 'l') {
             // last: replace and then stop
             subflags.do_all = false;
             line2 = lnum;
             break;
           }
           if (typed == 'a') {
             subflags.do_ask = false;
             break;
           }
           if (typed == Ctrl_E) {
             scrollup_clamp();
           } else if (typed == Ctrl_Y) {
             scrolldown_clamp();
           }
         }
         State = save_State;
         setmouse();
         if (vim_strchr(p_cpo, CPO_UNDO) != NULL) {
           no_u_sync--;
         }

         if (typed == 'n') {
           // For a multi-line match, put matchcol at the NUL at
           // the end of the line and set nmatch to one, so that
           // we continue looking for a match on the next line.
           // Avoids that ":%s/\nB\@=//gc" and ":%s/\n/,\r/gc"
           // get stuck when pressing 'n'.
           if (nmatch > 1) {
             matchcol = (colnr_T)strlen(sub_firstline);
             skip_match = true;
           }
           goto skip;
         }
         if (got_quit) {
           goto skip;
         }
       }

       // Move the cursor to the start of the match, so that we can
       // use "\=col(".").
       curwin->w_cursor.col = regmatch.startpos[0].col;

       // When the match included the "$" of the last line it may
       // go beyond the last line of the buffer.
       if (nmatch > curbuf->b_ml.ml_line_count - sub_firstlnum + 1) {
         nmatch = curbuf->b_ml.ml_line_count - sub_firstlnum + 1;
         current_match.end.lnum = sub_firstlnum + (linenr_T)nmatch;
         skip_match = true;
         // safety check
         if (nmatch < 0) {
           goto skip;
         }
       }

       // Save the line numbers for the preview buffer
       // NOTE: If the pattern matches a final newline, the next line will
       // be shown also, but should not be highlighted. Intentional for now.
       if (cmdpreview_ns > 0 && !has_second_delim) {
         current_match.start.col = regmatch.startpos[0].col;
         if (current_match.end.lnum == 0) {
           current_match.end.lnum = sub_firstlnum + (linenr_T)nmatch - 1;
         }
         current_match.end.col = regmatch.endpos[0].col;

         ADJUST_SUB_FIRSTLNUM();
         lnum += (linenr_T)nmatch - 1;

         goto skip;
       }

       // 3. Substitute the string. During 'inccommand' preview only do this if
       //    there is a replace pattern.
       if (cmdpreview_ns <= 0 || has_second_delim) {
         lnum_start = lnum;  // save the start lnum
         int save_ma = curbuf->b_p_ma;
         int save_sandbox = sandbox;
         if (subflags.do_count) {
           // prevent accidentally changing the buffer by a function
           curbuf->b_p_ma = false;
           sandbox++;
         }
         // Save flags for recursion.  They can change for e.g.
         // :s/^/\=execute("s#^##gn")
         subflags_T subflags_save = subflags;

         // Disallow changing text or switching window in an expression.
         textlock++;
         // Get length of substitution part, including the NUL.
         // When it fails sublen is zero.
         sublen = vim_regsub_multi(&regmatch,
                                   sub_firstlnum - regmatch.startpos[0].lnum,
                                   sub, sub_firstline, 0,
                                   REGSUB_BACKSLASH
                                   | (magic_isset() ? REGSUB_MAGIC : 0));
         textlock--;

         // If getting the substitute string caused an error, don't do
         // the replacement.
         // Don't keep flags set by a recursive call
         subflags = subflags_save;
         if (sublen == 0 || aborting() || subflags.do_count) {
           curbuf->b_p_ma = save_ma;
           sandbox = save_sandbox;
           goto skip;
         }

         // Need room for:
         // - result so far in new_start (not for first sub in line)
         // - original text up to match
         // - length of substituted part
         // - original text after match
         if (nmatch == 1) {
           p1 = sub_firstline;
         } else {
           linenr_T lastlnum = sub_firstlnum + (linenr_T)nmatch - 1;
           p1 = ml_get(lastlnum);
           nmatch_tl += nmatch - 1;
         }
         int copy_len = regmatch.startpos[0].col - copycol;
         new_end = sub_grow_buf(&new_start, &new_start_len,
                                (colnr_T)strlen(p1) - regmatch.endpos[0].col
                                + copy_len + sublen + 1);

         // copy the text up to the part that matched
         memmove(new_end, sub_firstline + copycol, (size_t)copy_len);
         new_end += copy_len;

         if (new_start_len - copy_len < sublen) {
           sublen = new_start_len - copy_len - 1;
         }

         // Finally, at this point we can know where the match actually will
         // start in the new text
         int start_col = (int)(new_end - new_start);
         current_match.start.col = start_col;

         textlock++;
         vim_regsub_multi(&regmatch,
                          sub_firstlnum - regmatch.startpos[0].lnum,
                          sub, new_end, sublen,
                          REGSUB_COPY | REGSUB_BACKSLASH
                          | (magic_isset() ? REGSUB_MAGIC : 0));
         textlock--;
         sub_nsubs++;
         did_sub = true;

         // Move the cursor to the start of the line, to avoid that it
         // is beyond the end of the line after the substitution.
         curwin->w_cursor.col = 0;

         // Remember next character to be copied.
         copycol = regmatch.endpos[0].col;

         ADJUST_SUB_FIRSTLNUM();

         // TODO(bfredl): this has some robustness issues, look into later.
         bcount_t replaced_bytes = 0;
         lpos_T start = regmatch.startpos[0];
         lpos_T end = regmatch.endpos[0];
         for (i = 0; i < nmatch - 1; i++) {
           replaced_bytes += (bcount_t)strlen(ml_get((linenr_T)(lnum_start + i))) + 1;
         }
         replaced_bytes += end.col - start.col;

         // Save the line number before processing newlines.
         linenr_T lnum_before_newlines = lnum;

         // Now the trick is to replace CTRL-M chars with a real line
         // break.  This would make it impossible to insert a CTRL-M in
         // the text.  The line break can be avoided by preceding the
         // CTRL-M with a backslash.  To be able to insert a backslash,
         // they must be doubled in the string and are halved here.
         // That is Vi compatible.
         for (p1 = new_end; *p1; p1++) {
           if (p1[0] == '\\' && p1[1] != NUL) {            // remove backslash
             sublen--;  // correct the byte counts for extmark_splice()
             STRMOVE(p1, p1 + 1);
           } else if (*p1 == CAR) {
             if (u_inssub(lnum) == OK) {             // prepare for undo
               *p1 = NUL;                            // truncate up to the CR
               ml_append(lnum - 1, new_start,
                         (colnr_T)(p1 - new_start + 1), false);
               mark_adjust(lnum + 1, (linenr_T)MAXLNUM, 1, 0, kExtmarkNOOP);

               if (subflags.do_ask) {
                 appended_lines(lnum - 1, 1);
               } else {
                 if (first_line == 0) {
                   first_line = lnum;
                 }
                 last_line = lnum + 1;
               }
               // All line numbers increase.
               sub_firstlnum++;
               lnum++;
               line2++;
               // move the cursor to the new line, like Vi
               curwin->w_cursor.lnum++;
               // copy the rest
               STRMOVE(new_start, p1 + 1);
               p1 = new_start - 1;
             }
           } else {
             p1 += utfc_ptr2len(p1) - 1;
           }
         }
         colnr_T new_endcol = (colnr_T)strlen(new_start);
         current_match.end.col = new_endcol;
         current_match.end.lnum = lnum;

         int matchcols = end.col - ((end.lnum == start.lnum)
                                    ? start.col : 0);
         int subcols = new_endcol - ((lnum == lnum_start) ? start_col : 0);
         if (!did_save) {
           // Required for Undo to work for extmarks.
           u_save_cursor();
           did_save = true;
         }

         // Store extmark data for this match.
         LineData *data = kv_pushp(line_matches);
         data->start_col = start_col;
         data->start = start;
         data->end = end;
         data->matchcols = matchcols;
         data->matchbytes = replaced_bytes;
         data->subcols = subcols;
         data->subbytes = sublen - 1;
         data->lnum_before = lnum_before_newlines;
         data->lnum_after = lnum;
       }

       // 4. If subflags.do_all is set, find next match.
       // Prevent endless loop with patterns that match empty
       // strings, e.g. :s/$/pat/g or :s/[a-z]* /(&)/g.
       // But ":s/\n/#/" is OK.
skip:
       // We already know that we did the last subst when we are at
       // the end of the line, except that a pattern like
       // "bar\|\nfoo" may match at the NUL.  "lnum" can be below
       // "line2" when there is a \zs in the pattern after a line
       // break.
       lastone = (skip_match
                  || got_int
                  || got_quit
                  || lnum > line2
                  || !(subflags.do_all || do_again)
                  || (sub_firstline[matchcol] == NUL && nmatch <= 1
                      && !re_multiline(regmatch.regprog)));
       nmatch = -1;

       // Replace the line in the buffer when needed.  This is
       // skipped when there are more matches.
       // The check for nmatch_tl is needed for when multi-line
       // matching must replace the lines before trying to do another
       // match, otherwise "\@<=" won't work.
       // When the match starts below where we start searching also
       // need to replace the line first (using \zs after \n).
       if (lastone
           || nmatch_tl > 0
           || (nmatch = vim_regexec_multi(&regmatch, curwin,
                                          curbuf, sub_firstlnum,
                                          matchcol, NULL, NULL)) == 0
           || regmatch.startpos[0].lnum > 0) {
         if (new_start != NULL) {
           // Copy the rest of the line, that didn't match.
           // "matchcol" has to be adjusted, we use the end of
           // the line as reference, because the substitute may
           // have changed the number of characters.  Same for
           // "prev_matchcol".
           strcat(new_start, sub_firstline + copycol);
           matchcol = (colnr_T)strlen(sub_firstline) - matchcol;
           prev_matchcol = (colnr_T)strlen(sub_firstline)
                           - prev_matchcol;

           if (u_savesub(lnum) != OK) {
             break;
           }
           ml_replace(lnum, new_start, true);

           // Call extmark_splice for each match on this line.
           for (size_t match_idx = 0; match_idx < kv_size(line_matches); match_idx++) {
             LineData *match = &kv_A(line_matches, match_idx);

             extmark_splice(curbuf, (int)match->lnum_before - 1, match->start_col,
                            match->end.lnum - match->start.lnum, match->matchcols,
                            match->matchbytes,
                            match->lnum_after - match->lnum_before,
                            match->subcols,
                            match->subbytes, kExtmarkUndo);
           }

           // Reset the match data for the next line.
           kv_size(line_matches) = 0;

           if (nmatch_tl > 0) {
             // Matched lines have now been substituted and are
             // useless, delete them.  The part after the match
             // has been appended to new_start, we don't need
             // it in the buffer.
             lnum++;
             if (u_savedel(lnum, nmatch_tl) != OK) {
               break;
             }
             for (i = 0; i < nmatch_tl; i++) {
               ml_delete(lnum);
             }
             mark_adjust(lnum, lnum + nmatch_tl - 1, MAXLNUM, -nmatch_tl, kExtmarkNOOP);
             if (subflags.do_ask) {
               deleted_lines(lnum, nmatch_tl);
             }
             lnum--;
             line2 -= nmatch_tl;  // nr of lines decreases
             nmatch_tl = 0;
           }

           // When asking, undo is saved each time, must also set
           // changed flag each time.
           if (subflags.do_ask) {
             changed_bytes(lnum, 0);
           } else {
             if (first_line == 0) {
               first_line = lnum;
             }
             last_line = lnum + 1;
           }

           sub_firstlnum = lnum;
           xfree(sub_firstline);                // free the temp buffer
           sub_firstline = new_start;
           new_start = NULL;
           matchcol = (colnr_T)strlen(sub_firstline) - matchcol;
           prev_matchcol = (colnr_T)strlen(sub_firstline)
                           - prev_matchcol;
           copycol = 0;
         }
         if (nmatch == -1 && !lastone) {
           nmatch = vim_regexec_multi(&regmatch, curwin, curbuf,
                                      sub_firstlnum, matchcol, NULL, NULL);
         }

         // 5. break if there isn't another match in this line
         if (nmatch <= 0) {
           // If the match found didn't start where we were
           // searching, do the next search in the line where we
           // found the match.
           if (nmatch == -1) {
             lnum -= regmatch.startpos[0].lnum;
           }

           // uncrustify:off

#define PUSH_PREVIEW_LINES() \
 do { \
   if (cmdpreview_ns > 0) { \
     linenr_T match_lines = current_match.end.lnum \
                            - current_match.start.lnum +1; \
     if (preview_lines.subresults.size > 0) { \
       linenr_T last = kv_last(preview_lines.subresults).end.lnum; \
       if (last == current_match.start.lnum) { \
         preview_lines.lines_needed += match_lines - 1; \
       } else { \
         preview_lines.lines_needed += match_lines; \
       } \
     } else { \
       preview_lines.lines_needed += match_lines; \
     } \
     kv_push(preview_lines.subresults, current_match); \
   } \
 } while (0)

           // uncrustify:on

           // Push the match to preview_lines.
           PUSH_PREVIEW_LINES();

           break;
         }
       }
       // Push the match to preview_lines.
       PUSH_PREVIEW_LINES();

       line_breakcheck();
     }

     if (did_sub) {
       sub_nlines++;
     }
     xfree(new_start);              // for when substitute was cancelled
     XFREE_CLEAR(sub_firstline);    // free the copy of the original line
     kv_destroy(line_matches);      // clean up match data
   }

   line_breakcheck();

   if (profile_passed_limit(timeout)) {
     got_quit = true;
   }
 }

 curbuf->deleted_bytes2 = 0;

 if (first_line != 0) {
   // Need to subtract the number of added lines from "last_line" to get
   // the line number before the change (same as adding the number of
   // deleted lines).
   i = curbuf->b_ml.ml_line_count - old_line_count;
   changed_lines(curbuf, first_line, 0, last_line - (linenr_T)i, (linenr_T)i, false);

   int64_t num_added = last_line - first_line;
   int64_t num_removed = num_added - i;
   buf_updates_send_changes(curbuf, first_line, num_added, num_removed);
 }

 xfree(sub_firstline);   // may have to free allocated copy of the line

 // ":s/pat//n" doesn't move the cursor
 if (subflags.do_count) {
   curwin->w_cursor = old_cursor;
 }

 if (sub_nsubs > start_nsubs) {
   if ((cmdmod.cmod_flags & CMOD_LOCKMARKS) == 0) {
     // Set the '[ and '] marks.
     curbuf->b_op_start.lnum = eap->line1;
     curbuf->b_op_end.lnum = line2;
     curbuf->b_op_start.col = curbuf->b_op_end.col = 0;
   }

   if (!global_busy) {
     // when interactive leave cursor on the match
     if (!subflags.do_ask) {
       if (endcolumn) {
         coladvance(curwin, MAXCOL);
       } else {
         beginline(BL_WHITE | BL_FIX);
       }
     }
     if (cmdpreview_ns <= 0 && !do_sub_msg(subflags.do_count) && subflags.do_ask && p_ch > 0) {
       msg("", 0);
     }
   } else {
     global_need_beginline = true;
   }
   if (subflags.do_print) {
     print_line(curwin->w_cursor.lnum, subflags.do_number, subflags.do_list, true);
   }
 } else if (!global_busy) {
   if (got_int) {
     // interrupted
     emsg(_(e_interr));
   } else if (got_match) {
     // did find something but nothing substituted
     if (p_ch > 0 && !ui_has(kUIMessages)) {
       msg("", 0);
     }
   } else if (subflags.do_error) {
     // nothing found
     semsg(_(e_patnotf2), get_search_pat());
   }
 }

 if (subflags.do_ask && hasAnyFolding(curwin)) {
   // Cursor position may require updating
   changed_window_setting(curwin);
 }

 vim_regfree(regmatch.regprog);
 xfree(sub);

 // Restore the flag values, they can be used for ":&&".
 subflags.do_all = save_do_all;
 subflags.do_ask = save_do_ask;

 int retv = 0;

 // Show 'inccommand' preview if there are matched lines.
 if (cmdpreview_ns > 0 && !aborting()) {
   if (got_quit || profile_passed_limit(timeout)) {  // Too slow, disable.
     set_option_direct(kOptInccommand, STATIC_CSTR_AS_OPTVAL(""), 0, SID_NONE);
   } else if (*p_icm != NUL && pat != NULL) {
     if (pre_hl_id == 0) {
       pre_hl_id = syn_check_group(S_LEN("Substitute"));
     }
     retv = show_sub(eap, old_cursor, &preview_lines, pre_hl_id, cmdpreview_ns, cmdpreview_bufnr);
   }
 }

 kv_destroy(preview_lines.subresults);
 return retv;
#undef ADJUST_SUB_FIRSTLNUM
#undef PUSH_PREVIEW_LINES
}

/// Give message for number of substitutions.
/// Can also be used after a ":global" command.
///
/// @param count_only  used 'n' flag for ":s"
///
/// @return            true if a message was given.
bool do_sub_msg(bool count_only)
{
 // Only report substitutions when:
 // - more than 'report' substitutions
 // - command was typed by user, or number of changed lines > 'report'
 // - giving messages is not disabled by 'lazyredraw'
 if (((sub_nsubs > p_report && (KeyTyped || sub_nlines > 1 || p_report < 1))
      || count_only)
     && messaging()) {
   if (got_int) {
     STRCPY(msg_buf, _("(Interrupted) "));
   } else {
     *msg_buf = NUL;
   }

   char *msg_single = count_only
                      ? NGETTEXT("%" PRId64 " match on %" PRId64 " line",
                                 "%" PRId64 " matches on %" PRId64 " line", sub_nsubs)
                      : NGETTEXT("%" PRId64 " substitution on %" PRId64 " line",
                                 "%" PRId64 " substitutions on %" PRId64 " line", sub_nsubs);
   char *msg_plural = count_only
                      ? NGETTEXT("%" PRId64 " match on %" PRId64 " lines",
                                 "%" PRId64 " matches on %" PRId64 " lines", sub_nsubs)
                      : NGETTEXT("%" PRId64 " substitution on %" PRId64 " lines",
                                 "%" PRId64 " substitutions on %" PRId64 " lines", sub_nsubs);
   vim_snprintf_add(msg_buf, sizeof(msg_buf),
                    NGETTEXT(msg_single, msg_plural, sub_nlines),
                    (int64_t)sub_nsubs, (int64_t)sub_nlines);
   if (msg(msg_buf, 0)) {
     // save message to display it after redraw
     set_keep_msg(msg_buf, 0);
   }
   return true;
 }
 if (got_int) {
   emsg(_(e_interr));
   return true;
 }
 return false;
}

static void global_exe_one(char *const cmd, const linenr_T lnum)
{
 curwin->w_cursor.lnum = lnum;
 curwin->w_cursor.col = 0;
 if (*cmd == NUL || *cmd == '\n') {
   do_cmdline("p", NULL, NULL, DOCMD_NOWAIT);
 } else {
   do_cmdline(cmd, NULL, NULL, DOCMD_NOWAIT);
 }
}

/// Execute a global command of the form:
///
/// g/pattern/X : execute X on all lines where pattern matches
/// v/pattern/X : execute X on all lines where pattern does not match
///
/// where 'X' is an EX command
///
/// The command character (as well as the trailing slash) is optional, and
/// is assumed to be 'p' if missing.
///
/// This is implemented in two passes: first we scan the file for the pattern and
/// set a mark for each line that (not) matches. Secondly we execute the command
/// for each line that has a mark. This is required because after deleting
/// lines we do not know where to search for the next match.
void ex_global(exarg_T *eap)
{
 linenr_T lnum;                // line number according to old situation
 int type;                     // first char of cmd: 'v' or 'g'
 char *cmd;                    // command argument

 char delim;                 // delimiter, normally '/'
 char *pat;
 size_t patlen;
 regmmatch_T regmatch;

 // When nesting the command works on one line.  This allows for
 // ":g/found/v/notfound/command".
 if (global_busy && (eap->line1 != 1
                     || eap->line2 != curbuf->b_ml.ml_line_count)) {
   // will increment global_busy to break out of the loop
   emsg(_("E147: Cannot do :global recursive with a range"));
   return;
 }

 if (eap->forceit) {               // ":global!" is like ":vglobal"
   type = 'v';
 } else {
   type = (uint8_t)(*eap->cmd);
 }
 cmd = eap->arg;
 int which_pat = RE_LAST;              // default: use last used regexp

 // undocumented vi feature:
 //    "\/" and "\?": use previous search pattern.
 //             "\&": use previous substitute pattern.
 if (*cmd == '\\') {
   cmd++;
   if (vim_strchr("/?&", (uint8_t)(*cmd)) == NULL) {
     emsg(_(e_backslash));
     return;
   }
   if (*cmd == '&') {
     which_pat = RE_SUBST;             // use previous substitute pattern
   } else {
     which_pat = RE_SEARCH;            // use previous search pattern
   }
   cmd++;
   pat = "";
   patlen = 0;
 } else if (*cmd == NUL) {
   emsg(_("E148: Regular expression missing from global"));
   return;
 } else if (check_regexp_delim(*cmd) == FAIL) {
   return;
 } else {
   delim = *cmd;               // get the delimiter
   cmd++;                      // skip delimiter if there is one
   pat = cmd;                  // remember start of pattern
   cmd = skip_regexp_ex(cmd, delim, magic_isset(), &eap->arg, NULL, NULL);
   if (cmd[0] == delim) {                  // end delimiter found
     *cmd++ = NUL;                         // replace it with a NUL
   }
   patlen = strlen(pat);
 }

 char *used_pat;
 if (search_regcomp(pat, patlen, &used_pat, RE_BOTH, which_pat,
                    SEARCH_HIS, &regmatch) == FAIL) {
   emsg(_(e_invcmd));
   return;
 }

 if (global_busy) {
   lnum = curwin->w_cursor.lnum;
   int match = vim_regexec_multi(&regmatch, curwin, curbuf, lnum, 0, NULL, NULL);
   if ((type == 'g' && match) || (type == 'v' && !match)) {
     global_exe_one(cmd, lnum);
   }
 } else {
   int ndone = 0;
   // pass 1: set marks for each (not) matching line
   for (lnum = eap->line1; lnum <= eap->line2 && !got_int; lnum++) {
     // a match on this line?
     int match = vim_regexec_multi(&regmatch, curwin, curbuf, lnum, 0, NULL, NULL);
     if (regmatch.regprog == NULL) {
       break;  // re-compiling regprog failed
     }
     if ((type == 'g' && match) || (type == 'v' && !match)) {
       ml_setmarked(lnum);
       ndone++;
     }
     line_breakcheck();
   }

   // pass 2: execute the command for each line that has been marked
   if (got_int) {
     msg(_(e_interr), 0);
   } else if (ndone == 0) {
     if (type == 'v') {
       smsg(0, _("Pattern found in every line: %s"), used_pat);
     } else {
       smsg(0, _("Pattern not found: %s"), used_pat);
     }
   } else {
     global_exe(cmd);
   }
   ml_clearmarked();         // clear rest of the marks
 }
 vim_regfree(regmatch.regprog);
}

/// Execute `cmd` on lines marked with ml_setmarked().
void global_exe(char *cmd)
{
 linenr_T old_lcount;      // b_ml.ml_line_count before the command
 buf_T *old_buf = curbuf;  // remember what buffer we started in
 linenr_T lnum;            // line number according to old situation

 // Set current position only once for a global command.
 // If global_busy is set, setpcmark() will not do anything.
 // If there is an error, global_busy will be incremented.
 setpcmark();

 // When the command writes a message, don't overwrite the command.
 msg_didout = true;

 sub_nsubs = 0;
 sub_nlines = 0;
 global_need_msg_kind = true;
 global_need_beginline = false;
 global_busy = 1;
 old_lcount = curbuf->b_ml.ml_line_count;

 while (!got_int && (lnum = ml_firstmarked()) != 0 && global_busy == 1) {
   global_exe_one(cmd, lnum);
   os_breakcheck();
 }

 global_busy = 0;
 if (global_need_beginline) {
   beginline(BL_WHITE | BL_FIX);
 } else {
   check_cursor(curwin);  // cursor may be beyond the end of the line
 }

 // the cursor may not have moved in the text but a change in a previous
 // line may move it on the screen
 changed_line_abv_curs();

 // If it looks like no message was written, allow overwriting the
 // command with the report for number of changes.
 if (msg_col == 0 && msg_scrolled == 0) {
   msg_didout = false;
 }

 // If substitutes done, report number of substitutes, otherwise report
 // number of extra or deleted lines.
 // Don't report extra or deleted lines in the edge case where the buffer
 // we are in after execution is different from the buffer we started in.
 if (!do_sub_msg(false) && curbuf == old_buf) {
   msgmore(curbuf->b_ml.ml_line_count - old_lcount);
 }
}

#if defined(EXITFREE)
void free_old_sub(void)
{
 sub_set_replacement((SubReplacementString) { NULL, 0, NULL });
}

#endif

/// Set up for a tagpreview.
///
/// @param undo_sync  sync undo when leaving the window
///
/// @return           true when it was created.
bool prepare_tagpreview(bool undo_sync)
{
 if (curwin->w_p_pvw) {
   return false;
 }

 // If there is already a preview window open, use that one.
 FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
   if (wp->w_p_pvw) {
     win_enter(wp, undo_sync);
     return false;
   }
 }

 // There is no preview window open yet.  Create one.
 if (win_split(g_do_tagpreview > 0 ? g_do_tagpreview : 0, 0)
     == FAIL) {
   return false;
 }
 curwin->w_p_pvw = true;
 curwin->w_p_wfh = true;
 RESET_BINDING(curwin);                // don't take over 'scrollbind' and 'cursorbind'
 curwin->w_p_diff = false;             // no 'diff'

 set_option_direct(kOptFoldcolumn, STATIC_CSTR_AS_OPTVAL("0"), 0, SID_NONE);  // no 'foldcolumn'
 return true;
}

/// Shows the effects of the :substitute command being typed ('inccommand').
/// If inccommand=split, shows a preview window and later restores the layout.
///
/// @return 1 if preview window isn't needed, 2 if preview window is needed.
static int show_sub(exarg_T *eap, pos_T old_cusr, PreviewLines *preview_lines, int hl_id,
                   int cmdpreview_ns, handle_T cmdpreview_bufnr)
 FUNC_ATTR_NONNULL_ALL
{
 char *save_shm_p = xstrdup(p_shm);
 PreviewLines lines = *preview_lines;
 buf_T *orig_buf = curbuf;
 // We keep a special-purpose buffer around, but don't assume it exists.
 buf_T *cmdpreview_buf = NULL;

 // disable file info message
 set_option_direct(kOptShortmess, STATIC_CSTR_AS_OPTVAL("F"), 0, SID_NONE);

 // Place cursor on nearest matching line, to undo do_sub() cursor placement.
 for (size_t i = 0; i < lines.subresults.size; i++) {
   SubResult curres = lines.subresults.items[i];
   if (curres.start.lnum >= old_cusr.lnum) {
     curwin->w_cursor.lnum = curres.start.lnum;
     curwin->w_cursor.col = curres.start.col;
     break;
   }  // Else: All matches are above, do_sub() already placed cursor.
 }

 // Update the topline to ensure that main window is on the correct line
 update_topline(curwin);

 // Width of the "| lnum|..." column which displays the line numbers.
 int col_width = 0;
 // Use preview window only when inccommand=split and range is not just the current line
 bool preview = (*p_icm == 's') && (eap->line1 != old_cusr.lnum || eap->line2 != old_cusr.lnum);

 if (preview) {
   cmdpreview_buf = buflist_findnr(cmdpreview_bufnr);
   assert(cmdpreview_buf != NULL);

   if (lines.subresults.size > 0) {
     SubResult last_match = kv_last(lines.subresults);
     // `last_match.end.lnum` may be 0 when using 'n' flag.
     linenr_T highest_lnum = MAX(last_match.start.lnum, last_match.end.lnum);
     assert(highest_lnum > 0);
     col_width = (int)log10(highest_lnum) + 1 + 3;
   }
 }

 char *str = NULL;  // construct the line to show in here
 colnr_T old_line_size = 0;
 colnr_T line_size = 0;
 linenr_T linenr_preview = 0;  // last line added to preview buffer
 linenr_T linenr_origbuf = 0;  // last line added to original buffer
 linenr_T next_linenr = 0;     // next line to show for the match

 for (size_t matchidx = 0; matchidx < lines.subresults.size; matchidx++) {
   SubResult match = lines.subresults.items[matchidx];

   if (cmdpreview_buf) {
     lpos_T p_start = { 0, match.start.col };  // match starts here in preview
     lpos_T p_end = { 0, match.end.col };    // ... and ends here

     // You Might Gonna Need It
     buf_ensure_loaded(cmdpreview_buf);

     if (match.pre_match == 0) {
       next_linenr = match.start.lnum;
     } else {
       next_linenr = match.pre_match;
     }
     // Don't add a line twice
     if (next_linenr == linenr_origbuf) {
       next_linenr++;
       p_start.lnum = linenr_preview;  // might be redefined below
       p_end.lnum = linenr_preview;  // might be redefined below
     }

     for (; next_linenr <= match.end.lnum; next_linenr++) {
       if (next_linenr == match.start.lnum) {
         p_start.lnum = linenr_preview + 1;
       }
       if (next_linenr == match.end.lnum) {
         p_end.lnum = linenr_preview + 1;
       }
       char *line;
       if (next_linenr == orig_buf->b_ml.ml_line_count + 1) {
         line = "";
       } else {
         line = ml_get_buf(orig_buf, next_linenr);
         line_size = ml_get_buf_len(orig_buf, next_linenr) + col_width + 1;

         // Reallocate if line not long enough
         if (line_size > old_line_size) {
           str = xrealloc(str, (size_t)line_size * sizeof(char));
           old_line_size = line_size;
         }
       }
       // Put "|lnum| line" into `str` and append it to the preview buffer.
       snprintf(str, (size_t)line_size, "|%*" PRIdLINENR "| %s", col_width - 3,
                next_linenr, line);
       if (linenr_preview == 0) {
         ml_replace_buf(cmdpreview_buf, 1, str, true, false);
       } else {
         ml_append_buf(cmdpreview_buf, linenr_preview, str, line_size, false);
       }
       linenr_preview += 1;
     }
     linenr_origbuf = match.end.lnum;

     bufhl_add_hl_pos_offset(cmdpreview_buf, cmdpreview_ns, hl_id, p_start, p_end, col_width);
   }
   bufhl_add_hl_pos_offset(orig_buf, cmdpreview_ns, hl_id, match.start, match.end, 0);
 }

 xfree(str);

 set_option_direct(kOptShortmess, CSTR_AS_OPTVAL(save_shm_p), 0, SID_NONE);
 xfree(save_shm_p);

 return preview ? 2 : 1;
}

/// :substitute command.
void ex_substitute(exarg_T *eap)
{
 do_sub(eap, profile_zero(), 0, 0);
}

/// :substitute command preview callback.
int ex_substitute_preview(exarg_T *eap, int cmdpreview_ns, handle_T cmdpreview_bufnr)
{
 // Only preview once the pattern delimiter has been typed
 if (*eap->arg && !ASCII_ISALNUM(*eap->arg)) {
   char *save_eap = eap->arg;
   int retv = do_sub(eap, profile_setlimit(p_rdt), cmdpreview_ns, cmdpreview_bufnr);
   eap->arg = save_eap;
   return retv;
 }

 return 0;
}

/// Skip over the pattern argument of ":vimgrep /pat/[g][j]".
/// Put the start of the pattern in "*s", unless "s" is NULL.
///
/// @param flags  if not NULL, put the flags in it: VGR_GLOBAL, VGR_NOJUMP.
/// @param s      if not NULL, terminate the pattern with a NUL.
///
/// @return  a pointer to the char just past the pattern plus flags.
char *skip_vimgrep_pat(char *p, char **s, int *flags)
{
 if (vim_isIDc((uint8_t)(*p))) {
   // ":vimgrep pattern fname"
   if (s != NULL) {
     *s = p;
   }
   p = skiptowhite(p);
   if (s != NULL && *p != NUL) {
     *p++ = NUL;
   }
 } else {
   // ":vimgrep /pattern/[g][j] fname"
   if (s != NULL) {
     *s = p + 1;
   }
   int c = (uint8_t)(*p);
   p = skip_regexp(p + 1, c, true);
   if (*p != c) {
     return NULL;
   }

   // Truncate the pattern.
   if (s != NULL) {
     *p = NUL;
   }
   p++;

   // Find the flags
   while (*p == 'g' || *p == 'j' || *p == 'f') {
     if (flags != NULL) {
       if (*p == 'g') {
         *flags |= VGR_GLOBAL;
       } else if (*p == 'j') {
         *flags |= VGR_NOJUMP;
       } else {
         *flags |= VGR_FUZZY;
       }
     }
     p++;
   }
 }
 return p;
}

/// List v:oldfiles in a nice way.
void ex_oldfiles(exarg_T *eap)
{
 list_T *l = get_vim_var_list(VV_OLDFILES);
 int nr = 0;

 if (l == NULL) {
   msg(_("No old files"), 0);
   return;
 }

 msg_start();
 msg_scroll = true;
 TV_LIST_ITER(l, li, {
   if (got_int) {
     break;
   }
   nr++;
   const char *fname = tv_get_string(TV_LIST_ITEM_TV(li));
   if (!message_filtered(fname)) {
     msg_outnum(nr);
     msg_puts(": ");
     msg_outtrans(tv_get_string(TV_LIST_ITEM_TV(li)), 0, false);
     msg_clr_eos();
     msg_putchar('\n');
     os_breakcheck();
   }
 });

 // Assume "got_int" was set to truncate the listing.
 got_int = false;

 // File selection prompt on ":browse oldfiles"
 if (cmdmod.cmod_flags & CMOD_BROWSE) {
   quit_more = false;
   nr = prompt_for_input(NULL, 0, false, NULL);
   msg_starthere();
   if (nr > 0 && nr <= tv_list_len(l)) {
     const char *const p = tv_list_find_str(l, nr - 1);
     if (p == NULL) {
       return;
     }
     char *const s = expand_env_save((char *)p);
     eap->arg = s;
     eap->cmdidx = CMD_edit;
     cmdmod.cmod_flags &= ~CMOD_BROWSE;
     do_exedit(eap, NULL);
     xfree(s);
   }
 }
}