src/terminal.c

/* vi:set ts=8 sts=4 sw=4 noet:
 *
 * VIM - Vi IMproved	by Bram Moolenaar
 *
 * Do ":help uganda"  in Vim to read copying and usage conditions.
 * Do ":help credits" in Vim to see a list of people who contributed.
 * See README.txt for an overview of the Vim source code.
 */

/*
 * Terminal window support, see ":help :terminal".
 *
 * There are three parts:
 * 1. Generic code for all systems.
 *    Uses libvterm for the terminal emulator.
 * 2. The MS-Windows implementation.
 *    Uses winpty.
 * 3. The Unix-like implementation.
 *    Uses pseudo-tty's (pty's).
 *
 * For each terminal one VTerm is constructed.  This uses libvterm.  A copy of
 * this library is in the libvterm directory.
 *
 * When a terminal window is opened, a job is started that will be connected to
 * the terminal emulator.
 *
 * If the terminal window has keyboard focus, typed keys are converted to the
 * terminal encoding and writing to the job over a channel.
 *
 * If the job produces output, it is written to the terminal emulator.  The
 * terminal emulator invokes callbacks when its screen content changes.  The
 * line range is stored in tl_dirty_row_start and tl_dirty_row_end.  Once in a
 * while, if the terminal window is visible, the screen contents is drawn.
 *
 * When the job ends the text is put in a buffer.  Redrawing then happens from
 * that buffer, attributes come from the scrollback buffer tl_scrollback.
 *
 * TODO:
 * - don't allow exiting Vim when a terminal is still running a job
 * - in bash mouse clicks are inserting characters.
 * - mouse scroll: when over other window, scroll that window.
 * - For the scrollback buffer store lines in the buffer, only attributes in
 *   tl_scrollback.
 * - When the job ends:
 *   - Need an option or argument to drop the window+buffer right away, to be
 *     used for a shell or Vim. 'termfinish'; "close", "open" (open window when
 *     job finishes).
 * - add option values to the command:
 *      :term <24x80> <close> vim notes.txt
 * - support different cursor shapes, colors and attributes
 * - make term_getcursor() return type (none/block/bar/underline) and
 *   attributes (color, blink, etc.)
 * - To set BS correctly, check get_stty(); Pass the fd of the pty.
 * - do not store terminal window in viminfo.  Or prefix term:// ?
 * - add a character in :ls output
 * - add 't' to mode()
 * - use win_del_lines() to make scroll-up efficient.
 * - implement term_setsize()
 * - add test for giving error for invalid 'termsize' value.
 * - support minimal size when 'termsize' is "rows*cols".
 * - support minimal size when 'termsize' is empty?
 * - implement "term" for job_start(): more job options when starting a
 *   terminal.
 * - if the job in the terminal does not support the mouse, we can use the
 *   mouse in the Terminal window for copy/paste.
 * - when 'encoding' is not utf-8, or the job is using another encoding, setup
 *   conversions.
 * - update ":help function-list" for terminal functions.
 * - In the GUI use a terminal emulator for :!cmd.
 * - Copy text in the vterm to the Vim buffer once in a while, so that
 *   completion works.
 */

#include "vim.h"

#if defined(FEAT_TERMINAL) || defined(PROTO)

#ifdef WIN3264
# define MIN(x,y) (x < y ? x : y)
# define MAX(x,y) (x > y ? x : y)
#endif

#include "libvterm/include/vterm.h"

typedef struct sb_line_S {
    int		    sb_cols;	/* can differ per line */
    VTermScreenCell *sb_cells;	/* allocated */
} sb_line_T;

/* typedef term_T in structs.h */
struct terminal_S {
    term_T	*tl_next;

    VTerm	*tl_vterm;
    job_T	*tl_job;
    buf_T	*tl_buffer;

    int		tl_terminal_mode;
    int		tl_channel_closed;

#ifdef WIN3264
    void	*tl_winpty_config;
    void	*tl_winpty;
#endif

    /* last known vterm size */
    int		tl_rows;
    int		tl_cols;
    /* vterm size does not follow window size */
    int		tl_rows_fixed;
    int		tl_cols_fixed;

    char_u	*tl_title; /* NULL or allocated */
    char_u	*tl_status_text; /* NULL or allocated */

    /* Range of screen rows to update.  Zero based. */
    int		tl_dirty_row_start; /* -1 if nothing dirty */
    int		tl_dirty_row_end;   /* row below last one to update */

    garray_T	tl_scrollback;
    int		tl_scrollback_scrolled;

    VTermPos	tl_cursor_pos;
    int		tl_cursor_visible;
};

/*
 * List of all active terminals.
 */
static term_T *first_term = NULL;


#define MAX_ROW 999999	    /* used for tl_dirty_row_end to update all rows */
#define KEY_BUF_LEN 200

/*
 * Functions with separate implementation for MS-Windows and Unix-like systems.
 */
static int term_and_job_init(term_T *term, int rows, int cols, char_u *cmd);
static void term_report_winsize(term_T *term, int rows, int cols);
static void term_free_vterm(term_T *term);

/**************************************
 * 1. Generic code for all systems.
 */

/*
 * Determine the terminal size from 'termsize' and the current window.
 * Assumes term->tl_rows and term->tl_cols are zero.
 */
    static void
set_term_and_win_size(term_T *term)
{
    if (*curwin->w_p_tms != NUL)
    {
	char_u *p = vim_strchr(curwin->w_p_tms, 'x') + 1;

	term->tl_rows = atoi((char *)curwin->w_p_tms);
	term->tl_cols = atoi((char *)p);
    }
    if (term->tl_rows == 0)
	term->tl_rows = curwin->w_height;
    else
    {
	win_setheight_win(term->tl_rows, curwin);
	term->tl_rows_fixed = TRUE;
    }
    if (term->tl_cols == 0)
	term->tl_cols = curwin->w_width;
    else
    {
	win_setwidth_win(term->tl_cols, curwin);
	term->tl_cols_fixed = TRUE;
    }
}

/*
 * ":terminal": open a terminal window and execute a job in it.
 */
    void
ex_terminal(exarg_T *eap)
{
    exarg_T	split_ea;
    win_T	*old_curwin = curwin;
    term_T	*term;
    char_u	*cmd = eap->arg;

    if (check_restricted() || check_secure())
	return;

    term = (term_T *)alloc_clear(sizeof(term_T));
    if (term == NULL)
	return;
    term->tl_dirty_row_end = MAX_ROW;
    term->tl_cursor_visible = TRUE;
    ga_init2(&term->tl_scrollback, sizeof(sb_line_T), 300);

    /* Open a new window or tab. */
    vim_memset(&split_ea, 0, sizeof(split_ea));
    split_ea.cmdidx = CMD_new;
    split_ea.cmd = (char_u *)"new";
    split_ea.arg = (char_u *)"";
    ex_splitview(&split_ea);
    if (curwin == old_curwin)
    {
	/* split failed */
	vim_free(term);
	return;
    }
    term->tl_buffer = curbuf;
    curbuf->b_term = term;

    /* Link the new terminal in the list of active terminals. */
    term->tl_next = first_term;
    first_term = term;

    if (cmd == NULL || *cmd == NUL)
	cmd = p_sh;

    {
	int	i;
	size_t	len = STRLEN(cmd) + 10;
	char_u	*p = alloc((int)len);

	for (i = 0; p != NULL; ++i)
	{
	    /* Prepend a ! to the command name to avoid the buffer name equals
	     * the executable, otherwise ":w!" would overwrite it. */
	    if (i == 0)
		vim_snprintf((char *)p, len, "!%s", cmd);
	    else
		vim_snprintf((char *)p, len, "!%s (%d)", cmd, i);
	    if (buflist_findname(p) == NULL)
	    {
		curbuf->b_ffname = p;
		break;
	    }
	}
    }
    curbuf->b_fname = curbuf->b_ffname;

    /* Mark the buffer as not modifiable. It can only be made modifiable after
     * the job finished. */
    curbuf->b_p_ma = FALSE;
    set_string_option_direct((char_u *)"buftype", -1,
				  (char_u *)"terminal", OPT_FREE|OPT_LOCAL, 0);

    set_term_and_win_size(term);

    /* System dependent: setup the vterm and start the job in it. */
    if (term_and_job_init(term, term->tl_rows, term->tl_cols, cmd) == OK)
    {
	/* store the size we ended up with */
	vterm_get_size(term->tl_vterm, &term->tl_rows, &term->tl_cols);
    }
    else
    {
	free_terminal(curbuf);

	/* Wiping out the buffer will also close the window and call
	 * free_terminal(). */
	do_buffer(DOBUF_WIPE, DOBUF_CURRENT, FORWARD, 0, TRUE);
    }
}

/*
 * Free the scrollback buffer for "term".
 */
    static void
free_scrollback(term_T *term)
{
    int i;

    for (i = 0; i < term->tl_scrollback.ga_len; ++i)
	vim_free(((sb_line_T *)term->tl_scrollback.ga_data + i)->sb_cells);
    ga_clear(&term->tl_scrollback);
}

/*
 * Free a terminal and everything it refers to.
 * Kills the job if there is one.
 * Called when wiping out a buffer.
 */
    void
free_terminal(buf_T *buf)
{
    term_T	*term = buf->b_term;
    term_T	*tp;

    if (term == NULL)
	return;
    if (first_term == term)
	first_term = term->tl_next;
    else
	for (tp = first_term; tp->tl_next != NULL; tp = tp->tl_next)
	    if (tp->tl_next == term)
	    {
		tp->tl_next = term->tl_next;
		break;
	    }

    if (term->tl_job != NULL)
    {
	if (term->tl_job->jv_status != JOB_ENDED
				      && term->tl_job->jv_status != JOB_FAILED)
	    job_stop(term->tl_job, NULL, "kill");
	job_unref(term->tl_job);
    }

    free_scrollback(term);

    term_free_vterm(term);
    vim_free(term->tl_title);
    vim_free(term->tl_status_text);
    vim_free(term);
    buf->b_term = NULL;
}

/*
 * Write job output "msg[len]" to the vterm.
 */
    static void
term_write_job_output(term_T *term, char_u *msg, size_t len)
{
    VTerm	*vterm = term->tl_vterm;
    char_u	*p;
    size_t	done;
    size_t	len_now;

    for (done = 0; done < len; done += len_now)
    {
	for (p = msg + done; p < msg + len; )
	{
	    if (*p == NL)
		break;
	    p += utf_ptr2len_len(p, (int)(len - (p - msg)));
	}
	len_now = p - msg - done;
	vterm_input_write(vterm, (char *)msg + done, len_now);
	if (p < msg + len && *p == NL)
	{
	    /* Convert NL to CR-NL, that appears to work best. */
	    vterm_input_write(vterm, "\r\n", 2);
	    ++len_now;
	}
    }

    /* this invokes the damage callbacks */
    vterm_screen_flush_damage(vterm_obtain_screen(vterm));
}

    static void
update_cursor(term_T *term, int redraw)
{
    if (term->tl_terminal_mode)
	return;
    setcursor();
    if (redraw && term->tl_buffer == curbuf)
    {
	if (term->tl_cursor_visible)
	    cursor_on();
	out_flush();
#ifdef FEAT_GUI
	if (gui.in_use)
	    gui_update_cursor(FALSE, FALSE);
#endif
    }
}

/*
 * Invoked when "msg" output from a job was received.  Write it to the terminal
 * of "buffer".
 */
    void
write_to_term(buf_T *buffer, char_u *msg, channel_T *channel)
{
    size_t	len = STRLEN(msg);
    term_T	*term = buffer->b_term;

    if (term->tl_vterm == NULL)
    {
	ch_logn(channel, "NOT writing %d bytes to terminal", (int)len);
	return;
    }
    ch_logn(channel, "writing %d bytes to terminal", (int)len);
    term_write_job_output(term, msg, len);

    if (!term->tl_terminal_mode)
    {
	/* TODO: only update once in a while. */
	update_screen(0);
	update_cursor(term, TRUE);
    }
}

/*
 * Send a mouse position and click to the vterm
 */
    static int
term_send_mouse(VTerm *vterm, int button, int pressed)
{
    VTermModifier   mod = VTERM_MOD_NONE;

    vterm_mouse_move(vterm, mouse_row - W_WINROW(curwin),
					    mouse_col - W_WINCOL(curwin), mod);
    vterm_mouse_button(vterm, button, pressed, mod);
    return TRUE;
}

/*
 * Convert typed key "c" into bytes to send to the job.
 * Return the number of bytes in "buf".
 */
    static int
term_convert_key(term_T *term, int c, char *buf)
{
    VTerm	    *vterm = term->tl_vterm;
    VTermKey	    key = VTERM_KEY_NONE;
    VTermModifier   mod = VTERM_MOD_NONE;
    int		    mouse = FALSE;

    switch (c)
    {
	case CAR:		key = VTERM_KEY_ENTER; break;
	case ESC:		key = VTERM_KEY_ESCAPE; break;
				/* VTERM_KEY_BACKSPACE becomes 0x7f DEL */
	case K_BS:		c = BS; break;
	case K_DEL:		key = VTERM_KEY_DEL; break;
	case K_DOWN:		key = VTERM_KEY_DOWN; break;
	case K_S_DOWN:		mod = VTERM_MOD_SHIFT;
				key = VTERM_KEY_DOWN; break;
	case K_END:		key = VTERM_KEY_END; break;
	case K_S_END:		mod = VTERM_MOD_SHIFT;
				key = VTERM_KEY_END; break;
	case K_C_END:		mod = VTERM_MOD_CTRL;
				key = VTERM_KEY_END; break;
	case K_F10:		key = VTERM_KEY_FUNCTION(10); break;
	case K_F11:		key = VTERM_KEY_FUNCTION(11); break;
	case K_F12:		key = VTERM_KEY_FUNCTION(12); break;
	case K_F1:		key = VTERM_KEY_FUNCTION(1); break;
	case K_F2:		key = VTERM_KEY_FUNCTION(2); break;
	case K_F3:		key = VTERM_KEY_FUNCTION(3); break;
	case K_F4:		key = VTERM_KEY_FUNCTION(4); break;
	case K_F5:		key = VTERM_KEY_FUNCTION(5); break;
	case K_F6:		key = VTERM_KEY_FUNCTION(6); break;
	case K_F7:		key = VTERM_KEY_FUNCTION(7); break;
	case K_F8:		key = VTERM_KEY_FUNCTION(8); break;
	case K_F9:		key = VTERM_KEY_FUNCTION(9); break;
	case K_HOME:		key = VTERM_KEY_HOME; break;
	case K_S_HOME:		mod = VTERM_MOD_SHIFT;
				key = VTERM_KEY_HOME; break;
	case K_C_HOME:		mod = VTERM_MOD_CTRL;
				key = VTERM_KEY_HOME; break;
	case K_INS:		key = VTERM_KEY_INS; break;
	case K_K0:		key = VTERM_KEY_KP_0; break;
	case K_K1:		key = VTERM_KEY_KP_1; break;
	case K_K2:		key = VTERM_KEY_KP_2; break;
	case K_K3:		key = VTERM_KEY_KP_3; break;
	case K_K4:		key = VTERM_KEY_KP_4; break;
	case K_K5:		key = VTERM_KEY_KP_5; break;
	case K_K6:		key = VTERM_KEY_KP_6; break;
	case K_K7:		key = VTERM_KEY_KP_7; break;
	case K_K8:		key = VTERM_KEY_KP_8; break;
	case K_K9:		key = VTERM_KEY_KP_9; break;
	case K_KDEL:		key = VTERM_KEY_DEL; break; /* TODO */
	case K_KDIVIDE:		key = VTERM_KEY_KP_DIVIDE; break;
	case K_KEND:		key = VTERM_KEY_KP_1; break; /* TODO */
	case K_KENTER:		key = VTERM_KEY_KP_ENTER; break;
	case K_KHOME:		key = VTERM_KEY_KP_7; break; /* TODO */
	case K_KINS:		key = VTERM_KEY_KP_0; break; /* TODO */
	case K_KMINUS:		key = VTERM_KEY_KP_MINUS; break;
	case K_KMULTIPLY:	key = VTERM_KEY_KP_MULT; break;
	case K_KPAGEDOWN:	key = VTERM_KEY_KP_3; break; /* TODO */
	case K_KPAGEUP:		key = VTERM_KEY_KP_9; break; /* TODO */
	case K_KPLUS:		key = VTERM_KEY_KP_PLUS; break;
	case K_KPOINT:		key = VTERM_KEY_KP_PERIOD; break;
	case K_LEFT:		key = VTERM_KEY_LEFT; break;
	case K_S_LEFT:		mod = VTERM_MOD_SHIFT;
				key = VTERM_KEY_LEFT; break;
	case K_C_LEFT:		mod = VTERM_MOD_CTRL;
				key = VTERM_KEY_LEFT; break;
	case K_PAGEDOWN:	key = VTERM_KEY_PAGEDOWN; break;
	case K_PAGEUP:		key = VTERM_KEY_PAGEUP; break;
	case K_RIGHT:		key = VTERM_KEY_RIGHT; break;
	case K_S_RIGHT:		mod = VTERM_MOD_SHIFT;
				key = VTERM_KEY_RIGHT; break;
	case K_C_RIGHT:		mod = VTERM_MOD_CTRL;
				key = VTERM_KEY_RIGHT; break;
	case K_UP:		key = VTERM_KEY_UP; break;
	case K_S_UP:		mod = VTERM_MOD_SHIFT;
				key = VTERM_KEY_UP; break;
	case TAB:		key = VTERM_KEY_TAB; break;

	case K_MOUSEUP:		mouse = term_send_mouse(vterm, 5, 1); break;
	case K_MOUSEDOWN:	mouse = term_send_mouse(vterm, 4, 1); break;
	case K_MOUSELEFT:	/* TODO */ return 0;
	case K_MOUSERIGHT:	/* TODO */ return 0;

	case K_LEFTMOUSE:
	case K_LEFTMOUSE_NM:	mouse = term_send_mouse(vterm, 1, 1); break;
	case K_LEFTDRAG:	mouse = term_send_mouse(vterm, 1, 1); break;
	case K_LEFTRELEASE:
	case K_LEFTRELEASE_NM:	mouse = term_send_mouse(vterm, 1, 0); break;
	case K_MIDDLEMOUSE:	mouse = term_send_mouse(vterm, 2, 1); break;
	case K_MIDDLEDRAG:	mouse = term_send_mouse(vterm, 2, 1); break;
	case K_MIDDLERELEASE:	mouse = term_send_mouse(vterm, 2, 0); break;
	case K_RIGHTMOUSE:	mouse = term_send_mouse(vterm, 3, 1); break;
	case K_RIGHTDRAG:	mouse = term_send_mouse(vterm, 3, 1); break;
	case K_RIGHTRELEASE:	mouse = term_send_mouse(vterm, 3, 0); break;
	case K_X1MOUSE:		/* TODO */ return 0;
	case K_X1DRAG:		/* TODO */ return 0;
	case K_X1RELEASE:	/* TODO */ return 0;
	case K_X2MOUSE:		/* TODO */ return 0;
	case K_X2DRAG:		/* TODO */ return 0;
	case K_X2RELEASE:	/* TODO */ return 0;

	case K_IGNORE:		return 0;
	case K_NOP:		return 0;
	case K_UNDO:		return 0;
	case K_HELP:		return 0;
	case K_XF1:		key = VTERM_KEY_FUNCTION(1); break;
	case K_XF2:		key = VTERM_KEY_FUNCTION(2); break;
	case K_XF3:		key = VTERM_KEY_FUNCTION(3); break;
	case K_XF4:		key = VTERM_KEY_FUNCTION(4); break;
	case K_SELECT:		return 0;
#ifdef FEAT_GUI
	case K_VER_SCROLLBAR:	return 0;
	case K_HOR_SCROLLBAR:	return 0;
#endif
#ifdef FEAT_GUI_TABLINE
	case K_TABLINE:		return 0;
	case K_TABMENU:		return 0;
#endif
#ifdef FEAT_NETBEANS_INTG
	case K_F21:		key = VTERM_KEY_FUNCTION(21); break;
#endif
#ifdef FEAT_DND
	case K_DROP:		return 0;
#endif
#ifdef FEAT_AUTOCMD
	case K_CURSORHOLD:	return 0;
#endif
	case K_PS:		vterm_keyboard_start_paste(vterm); return 0;
	case K_PE:		vterm_keyboard_end_paste(vterm); return 0;
    }

    /*
     * Convert special keys to vterm keys:
     * - Write keys to vterm: vterm_keyboard_key()
     * - Write output to channel.
     * TODO: use mod_mask
     */
    if (key != VTERM_KEY_NONE)
	/* Special key, let vterm convert it. */
	vterm_keyboard_key(vterm, key, mod);
    else if (!mouse)
	/* Normal character, let vterm convert it. */
	vterm_keyboard_unichar(vterm, c, mod);

    /* Read back the converted escape sequence. */
    return (int)vterm_output_read(vterm, buf, KEY_BUF_LEN);
}

/*
 * Return TRUE if the job for "term" is still running.
 */
    int
term_job_running(term_T *term)
{
    /* Also consider the job finished when the channel is closed, to avoid a
     * race condition when updating the title. */
    return term->tl_job != NULL
	&& term->tl_job->jv_status == JOB_STARTED
	&& channel_is_open(term->tl_job->jv_channel);
}

/*
 * Add the last line of the scrollback buffer to the buffer in the window.
 */
    static void
add_scrollback_line_to_buffer(term_T *term)
{
    linenr_T	    lnum = term->tl_scrollback.ga_len - 1;
    sb_line_T	    *line = (sb_line_T *)term->tl_scrollback.ga_data + lnum;
    garray_T	    ga;
    int		    c;
    int		    col;
    int		    i;

    ga_init2(&ga, 1, 100);
    for (col = 0; col < line->sb_cols; col += line->sb_cells[col].width)
    {
	if (ga_grow(&ga, MB_MAXBYTES) == FAIL)
	    goto failed;
	for (i = 0; (c = line->sb_cells[col].chars[i]) > 0 || i == 0; ++i)
	    ga.ga_len += mb_char2bytes(c == NUL ? ' ' : c,
					 (char_u *)ga.ga_data + ga.ga_len);
    }
    if (ga_grow(&ga, 1) == FAIL)
	goto failed;
    *((char_u *)ga.ga_data + ga.ga_len) = NUL;
    ml_append_buf(term->tl_buffer, lnum, ga.ga_data, ga.ga_len + 1, FALSE);

    if (lnum == 0)
    {
	/* Delete the empty line that was in the empty buffer. */
	curbuf = term->tl_buffer;
	ml_delete(2, FALSE);
	curbuf = curwin->w_buffer;
    }

failed:
    ga_clear(&ga);
}

/*
 * Add the current lines of the terminal to scrollback and to the buffer.
 * Called after the job has ended and when switching to Terminal mode.
 */
    static void
move_terminal_to_buffer(term_T *term)
{
    win_T	    *wp;
    int		    len;
    int		    lines_skipped = 0;
    VTermPos	    pos;
    VTermScreenCell cell;
    VTermScreenCell *p;
    VTermScreen	    *screen = vterm_obtain_screen(term->tl_vterm);

    for (pos.row = 0; pos.row < term->tl_rows; ++pos.row)
    {
	len = 0;
	for (pos.col = 0; pos.col < term->tl_cols; ++pos.col)
	    if (vterm_screen_get_cell(screen, pos, &cell) != 0
						       && cell.chars[0] != NUL)
		len = pos.col + 1;

	if (len == 0)
	    ++lines_skipped;
	else
	{
	    while (lines_skipped > 0)
	    {
		/* Line was skipped, add an empty line. */
		--lines_skipped;
		if (ga_grow(&term->tl_scrollback, 1) == OK)
		{
		    sb_line_T *line = (sb_line_T *)term->tl_scrollback.ga_data
						  + term->tl_scrollback.ga_len;

		    line->sb_cols = 0;
		    line->sb_cells = NULL;
		    ++term->tl_scrollback.ga_len;

		    add_scrollback_line_to_buffer(term);
		}
	    }

	    p = (VTermScreenCell *)alloc((int)sizeof(VTermScreenCell) * len);
	    if (p != NULL && ga_grow(&term->tl_scrollback, 1) == OK)
	    {
		sb_line_T *line = (sb_line_T *)term->tl_scrollback.ga_data
						  + term->tl_scrollback.ga_len;

		for (pos.col = 0; pos.col < len; ++pos.col)
		{
		    if (vterm_screen_get_cell(screen, pos, &cell) == 0)
			vim_memset(p + pos.col, 0, sizeof(cell));
		    else
			p[pos.col] = cell;
		}
		line->sb_cols = len;
		line->sb_cells = p;
		++term->tl_scrollback.ga_len;

		add_scrollback_line_to_buffer(term);
	    }
	    else
		vim_free(p);
	}
    }

    FOR_ALL_WINDOWS(wp)
    {
	if (wp->w_buffer == term->tl_buffer)
	{
	    wp->w_cursor.lnum = term->tl_buffer->b_ml.ml_line_count;
	    wp->w_cursor.col = 0;
	    wp->w_valid = 0;
	    redraw_win_later(wp, NOT_VALID);
	}
    }
}

    static void
set_terminal_mode(term_T *term, int on)
{
    term->tl_terminal_mode = on;
    vim_free(term->tl_status_text);
    term->tl_status_text = NULL;
    if (term->tl_buffer == curbuf)
	maketitle();
}

/*
 * Called after the job if finished and Terminal mode is not active:
 * Move the vterm contents into the scrollback buffer and free the vterm.
 */
    static void
cleanup_vterm(term_T *term)
{
    move_terminal_to_buffer(term);
    term_free_vterm(term);
    set_terminal_mode(term, FALSE);
}

/*
 * Switch from sending keys to the job to Terminal-Normal mode.
 * Suspends updating the terminal window.
 */
    static void
term_enter_terminal_mode()
{
    term_T *term = curbuf->b_term;

    /* Append the current terminal contents to the buffer. */
    move_terminal_to_buffer(term);

    set_terminal_mode(term, TRUE);
}

/*
 * Returns TRUE if the current window contains a terminal and we are in
 * Terminal-Normal mode.
 */
    int
term_in_terminal_mode()
{
    term_T *term = curbuf->b_term;

    return term != NULL && term->tl_terminal_mode;
}

/*
 * Switch from Terminal-Normal mode to sending keys to the job.
 * Restores updating the terminal window.
 */
    void
term_leave_terminal_mode()
{
    term_T	*term = curbuf->b_term;
    sb_line_T	*line;
    garray_T	*gap;

    /* Remove the terminal contents from the scrollback and the buffer. */
    gap = &term->tl_scrollback;
    while (curbuf->b_ml.ml_line_count > term->tl_scrollback_scrolled)
    {
	ml_delete(curbuf->b_ml.ml_line_count, FALSE);
	line = (sb_line_T *)gap->ga_data + gap->ga_len - 1;
	vim_free(line->sb_cells);
	--gap->ga_len;
	if (gap->ga_len == 0)
	    break;
    }
    check_cursor();

    set_terminal_mode(term, FALSE);

    if (term->tl_channel_closed)
	cleanup_vterm(term);
    redraw_buf_and_status_later(curbuf, NOT_VALID);
}

/*
 * Get a key from the user without mapping.
 * TODO: use terminal mode mappings.
 */
    static int
term_vgetc()
{
    int c;

    ++no_mapping;
    ++allow_keys;
    got_int = FALSE;
    c = vgetc();
    got_int = FALSE;
    --no_mapping;
    --allow_keys;
    return c;
}

/*
 * Send keys to terminal.
 */
    static int
send_keys_to_term(term_T *term, int c, int typed)
{
    char	msg[KEY_BUF_LEN];
    size_t	len;
    static int	mouse_was_outside = FALSE;
    int		dragging_outside = FALSE;

    /* Catch keys that need to be handled as in Normal mode. */
    switch (c)
    {
	case NUL:
	case K_ZERO:
	    if (typed)
		stuffcharReadbuff(c);
	    return FAIL;

	case K_IGNORE:
	    return FAIL;

	case K_LEFTDRAG:
	case K_MIDDLEDRAG:
	case K_RIGHTDRAG:
	case K_X1DRAG:
	case K_X2DRAG:
	    dragging_outside = mouse_was_outside;
	    /* FALLTHROUGH */
	case K_LEFTMOUSE:
	case K_LEFTMOUSE_NM:
	case K_LEFTRELEASE:
	case K_LEFTRELEASE_NM:
	case K_MIDDLEMOUSE:
	case K_MIDDLERELEASE:
	case K_RIGHTMOUSE:
	case K_RIGHTRELEASE:
	case K_X1MOUSE:
	case K_X1RELEASE:
	case K_X2MOUSE:
	case K_X2RELEASE:
	    if (mouse_row < W_WINROW(curwin)
		    || mouse_row >= (W_WINROW(curwin) + curwin->w_height)
		    || mouse_col < W_WINCOL(curwin)
		    || mouse_col >= W_ENDCOL(curwin)
		    || dragging_outside)
	    {
		/* click outside the current window */
		if (typed)
		{
		    stuffcharReadbuff(c);
		    mouse_was_outside = TRUE;
		}
		return FAIL;
	    }
    }
    if (typed)
	mouse_was_outside = FALSE;

    /* Convert the typed key to a sequence of bytes for the job. */
    len = term_convert_key(term, c, msg);
    if (len > 0)
	/* TODO: if FAIL is returned, stop? */
	channel_send(term->tl_job->jv_channel, PART_IN,
						 (char_u *)msg, (int)len, NULL);

    return OK;
}

    static void
position_cursor(win_T *wp, VTermPos *pos)
{
    wp->w_wrow = MIN(pos->row, MAX(0, wp->w_height - 1));
    wp->w_wcol = MIN(pos->col, MAX(0, wp->w_width - 1));
    wp->w_valid |= (VALID_WCOL|VALID_WROW);
}

/*
 * Handle CTRL-W "": send register contents to the job.
 */
    static void
term_paste_register(int prev_c UNUSED)
{
    int		c;
    list_T	*l;
    listitem_T	*item;
    long	reglen = 0;
    int		type;

#ifdef FEAT_CMDL_INFO
    if (add_to_showcmd(prev_c))
    if (add_to_showcmd('"'))
	out_flush();
#endif
    c = term_vgetc();
#ifdef FEAT_CMDL_INFO
    clear_showcmd();
#endif

    /* CTRL-W "= prompt for expression to evaluate. */
    if (c == '=' && get_expr_register() != '=')
	return;

    l = (list_T *)get_reg_contents(c, GREG_LIST);
    if (l != NULL)
    {
	type = get_reg_type(c, &reglen);
	for (item = l->lv_first; item != NULL; item = item->li_next)
	{
	    char_u *s = get_tv_string(&item->li_tv);

	    channel_send(curbuf->b_term->tl_job->jv_channel, PART_IN,
							   s, STRLEN(s), NULL);
	    if (item->li_next != NULL || type == MLINE)
		channel_send(curbuf->b_term->tl_job->jv_channel, PART_IN,
						      (char_u *)"\r", 1, NULL);
	}
	list_free(l);
    }
}

/*
 * Returns TRUE if the current window contains a terminal and we are sending
 * keys to the job.
 */
    int
term_use_loop()
{
    term_T *term = curbuf->b_term;

    return term != NULL
	&& !term->tl_terminal_mode
	&& term->tl_vterm != NULL
	&& term_job_running(term);
}

/*
 * Wait for input and send it to the job.
 * Return when the start of a CTRL-W command is typed or anything else that
 * should be handled as a Normal mode command.
 * Returns OK if a typed character is to be handled in Normal mode, FAIL if
 * the terminal was closed.
 */
    int
terminal_loop(void)
{
    int		c;
    int		termkey = 0;

    if (*curwin->w_p_tk != NUL)
	termkey = string_to_key(curwin->w_p_tk, TRUE);
    position_cursor(curwin, &curbuf->b_term->tl_cursor_pos);

    for (;;)
    {
	/* TODO: skip screen update when handling a sequence of keys. */
	/* Repeat redrawing in case a message is received while redrawing. */
	while (curwin->w_redr_type != 0)
	    update_screen(0);
	update_cursor(curbuf->b_term, FALSE);

	c = term_vgetc();
	if (curbuf->b_term->tl_vterm == NULL
					  || !term_job_running(curbuf->b_term))
	    /* job finished while waiting for a character */
	    break;

#ifdef UNIX
	may_send_sigint(c, curbuf->b_term->tl_job->jv_pid, 0);
#endif
#ifdef WIN3264
	if (c == Ctrl_C)
	    /* We don't know if the job can handle CTRL-C itself or not, this
	     * may kill the shell instead of killing the command running in the
	     * shell. */
	    mch_stop_job(curbuf->b_term->tl_job, (char_u *)"quit")
#endif

	if (c == (termkey == 0 ? Ctrl_W : termkey))
	{
	    int	    prev_c = c;

#ifdef FEAT_CMDL_INFO
	    if (add_to_showcmd(c))
		out_flush();
#endif
	    c = term_vgetc();
#ifdef FEAT_CMDL_INFO
	    clear_showcmd();
#endif
	    if (curbuf->b_term->tl_vterm == NULL
					  || !term_job_running(curbuf->b_term))
		/* job finished while waiting for a character */
		break;

	    if (termkey == 0 && c == '.')
	    {
		/* "CTRL-W .": send CTRL-W to the job */
		c = Ctrl_W;
	    }
	    else if (c == 'N')
	    {
		term_enter_terminal_mode();
		return FAIL;
	    }
	    else if (c == '"')
	    {
		term_paste_register(prev_c);
		continue;
	    }
	    else if (termkey == 0 || c != termkey)
	    {
		stuffcharReadbuff(Ctrl_W);
		stuffcharReadbuff(c);
		return OK;
	    }
	}
	if (send_keys_to_term(curbuf->b_term, c, TRUE) != OK)
	    return OK;
    }
    return FAIL;
}

/*
 * Called when a job has finished.
 * This updates the title and status, but does not close the vter, because
 * there might still be pending output in the channel.
 */
    void
term_job_ended(job_T *job)
{
    term_T *term;
    int	    did_one = FALSE;

    for (term = first_term; term != NULL; term = term->tl_next)
	if (term->tl_job == job)
	{
	    vim_free(term->tl_title);
	    term->tl_title = NULL;
	    vim_free(term->tl_status_text);
	    term->tl_status_text = NULL;
	    redraw_buf_and_status_later(term->tl_buffer, VALID);
	    did_one = TRUE;
	}
    if (did_one)
	redraw_statuslines();
    if (curbuf->b_term != NULL)
    {
	if (curbuf->b_term->tl_job == job)
	    maketitle();
	update_cursor(curbuf->b_term, TRUE);
    }
}

    static void
may_toggle_cursor(term_T *term)
{
    if (curbuf == term->tl_buffer)
    {
	if (term->tl_cursor_visible)
	    cursor_on();
	else
	    cursor_off();
    }
}

    static int
handle_damage(VTermRect rect, void *user)
{
    term_T *term = (term_T *)user;

    term->tl_dirty_row_start = MIN(term->tl_dirty_row_start, rect.start_row);
    term->tl_dirty_row_end = MAX(term->tl_dirty_row_end, rect.end_row);
    redraw_buf_later(term->tl_buffer, NOT_VALID);
    return 1;
}

    static int
handle_moverect(VTermRect dest UNUSED, VTermRect src UNUSED, void *user)
{
    term_T	*term = (term_T *)user;

    /* TODO */
    redraw_buf_later(term->tl_buffer, NOT_VALID);
    return 1;
}

    static int
handle_movecursor(
	VTermPos pos,
	VTermPos oldpos UNUSED,
	int visible,
	void *user)
{
    term_T	*term = (term_T *)user;
    win_T	*wp;

    term->tl_cursor_pos = pos;
    term->tl_cursor_visible = visible;

    FOR_ALL_WINDOWS(wp)
    {
	if (wp->w_buffer == term->tl_buffer)
	    position_cursor(wp, &pos);
    }
    if (term->tl_buffer == curbuf && !term->tl_terminal_mode)
    {
	may_toggle_cursor(term);
	update_cursor(term, term->tl_cursor_visible);
    }

    return 1;
}

    static int
handle_settermprop(
	VTermProp prop,
	VTermValue *value,
	void *user)
{
    term_T	*term = (term_T *)user;

    switch (prop)
    {
	case VTERM_PROP_TITLE:
	    vim_free(term->tl_title);
	    term->tl_title = vim_strsave((char_u *)value->string);
	    vim_free(term->tl_status_text);
	    term->tl_status_text = NULL;
	    if (term == curbuf->b_term)
		maketitle();
	    break;

	case VTERM_PROP_CURSORVISIBLE:
	    term->tl_cursor_visible = value->boolean;
	    may_toggle_cursor(term);
	    out_flush();
	    break;

	default:
	    break;
    }
    /* Always return 1, otherwise vterm doesn't store the value internally. */
    return 1;
}

/*
 * The job running in the terminal resized the terminal.
 */
    static int
handle_resize(int rows, int cols, void *user)
{
    term_T	*term = (term_T *)user;
    win_T	*wp;

    term->tl_rows = rows;
    term->tl_cols = cols;
    FOR_ALL_WINDOWS(wp)
    {
	if (wp->w_buffer == term->tl_buffer)
	{
	    win_setheight_win(rows, wp);
	    win_setwidth_win(cols, wp);
	}
    }

    redraw_buf_later(term->tl_buffer, NOT_VALID);
    return 1;
}

/*
 * Handle a line that is pushed off the top of the screen.
 */
    static int
handle_pushline(int cols, const VTermScreenCell *cells, void *user)
{
    term_T	*term = (term_T *)user;

    /* TODO: Limit the number of lines that are stored. */
    /* TODO: put the text in the buffer. */
    if (ga_grow(&term->tl_scrollback, 1) == OK)
    {
	VTermScreenCell *p = NULL;
	int		len = 0;
	int		i;
	sb_line_T	*line;

	/* do not store empty cells at the end */
	for (i = 0; i < cols; ++i)
	    if (cells[i].chars[0] != 0)
		len = i + 1;

	if (len > 0)
	    p = (VTermScreenCell *)alloc((int)sizeof(VTermScreenCell) * len);
	if (p != NULL)
	    mch_memmove(p, cells, sizeof(VTermScreenCell) * len);

	line = (sb_line_T *)term->tl_scrollback.ga_data
						  + term->tl_scrollback.ga_len;
	line->sb_cols = len;
	line->sb_cells = p;
	++term->tl_scrollback.ga_len;
	++term->tl_scrollback_scrolled;

	add_scrollback_line_to_buffer(term);
    }
    return 0; /* ignored */
}

static VTermScreenCallbacks screen_callbacks = {
  handle_damage,	/* damage */
  handle_moverect,	/* moverect */
  handle_movecursor,	/* movecursor */
  handle_settermprop,	/* settermprop */
  NULL,			/* bell */
  handle_resize,	/* resize */
  handle_pushline,	/* sb_pushline */
  NULL			/* sb_popline */
};

/*
 * Called when a channel has been closed.
 * If this was a channel for a terminal window then finish it up.
 */
    void
term_channel_closed(channel_T *ch)
{
    term_T *term;
    int	    did_one = FALSE;

    for (term = first_term; term != NULL; term = term->tl_next)
	if (term->tl_job == ch->ch_job)
	{
	    term->tl_channel_closed = TRUE;

	    vim_free(term->tl_title);
	    term->tl_title = NULL;
	    vim_free(term->tl_status_text);
	    term->tl_status_text = NULL;

	    /* Unless in Terminal-Normal mode: clear the vterm. */
	    if (!term->tl_terminal_mode)
		cleanup_vterm(term);

	    redraw_buf_and_status_later(term->tl_buffer, NOT_VALID);
	    did_one = TRUE;
	}
    if (did_one)
    {
	redraw_statuslines();

	/* Need to break out of vgetc(). */
	ins_char_typebuf(K_IGNORE);

	term = curbuf->b_term;
	if (term != NULL)
	{
	    if (term->tl_job == ch->ch_job)
		maketitle();
	    update_cursor(term, term->tl_cursor_visible);
	}
    }
}

/*
 * Reverse engineer the RGB value into a cterm color index.
 * First color is 1.  Return 0 if no match found.
 */
    static int
color2index(VTermColor *color, int fg, int *boldp)
{
    int red = color->red;
    int blue = color->blue;
    int green = color->green;

    /* The argument for lookup_color() is for the color_names[] table. */
    if (red == 0)
    {
	if (green == 0)
	{
	    if (blue == 0)
		return lookup_color(0, fg, boldp) + 1; /* black */
	    if (blue == 224)
		return lookup_color(1, fg, boldp) + 1; /* dark blue */
	}
	else if (green == 224)
	{
	    if (blue == 0)
		return lookup_color(2, fg, boldp) + 1; /* dark green */
	    if (blue == 224)
		return lookup_color(3, fg, boldp) + 1; /* dark cyan */
	}
    }
    else if (red == 224)
    {
	if (green == 0)
	{
	    if (blue == 0)
		return lookup_color(4, fg, boldp) + 1; /* dark red */
	    if (blue == 224)
		return lookup_color(5, fg, boldp) + 1; /* dark magenta */
	}
	else if (green == 224)
	{
	    if (blue == 0)
		return lookup_color(6, fg, boldp) + 1; /* dark yellow / brown */
	    if (blue == 224)
		return lookup_color(8, fg, boldp) + 1; /* white / light grey */
	}
    }
    else if (red == 128)
    {
	if (green == 128 && blue == 128)
	    return lookup_color(12, fg, boldp) + 1; /* high intensity black / dark grey */
    }
    else if (red == 255)
    {
	if (green == 64)
	{
	    if (blue == 64)
		return lookup_color(20, fg, boldp) + 1;  /* light red */
	    if (blue == 255)
		return lookup_color(22, fg, boldp) + 1;  /* light magenta */
	}
	else if (green == 255)
	{
	    if (blue == 64)
		return lookup_color(24, fg, boldp) + 1;  /* yellow */
	    if (blue == 255)
		return lookup_color(26, fg, boldp) + 1;  /* white */
	}
    }
    else if (red == 64)
    {
	if (green == 64)
	{
	    if (blue == 255)
		return lookup_color(14, fg, boldp) + 1;  /* light blue */
	}
	else if (green == 255)
	{
	    if (blue == 64)
		return lookup_color(16, fg, boldp) + 1;  /* light green */
	    if (blue == 255)
		return lookup_color(18, fg, boldp) + 1;  /* light cyan */
	}
    }
    if (t_colors >= 256)
    {
	if (red == blue && red == green)
	{
	    /* 24-color greyscale */
	    static int cutoff[23] = {
		0x05, 0x10, 0x1B, 0x26, 0x31, 0x3C, 0x47, 0x52,
		0x5D, 0x68, 0x73, 0x7F, 0x8A, 0x95, 0xA0, 0xAB,
		0xB6, 0xC1, 0xCC, 0xD7, 0xE2, 0xED, 0xF9};
	    int i;

	    for (i = 0; i < 23; ++i)
		if (red < cutoff[i])
		    return i + 233;
	    return 256;
	}

	/* 216-color cube */
	return 17 + ((red + 25) / 0x33) * 36
	          + ((green + 25) / 0x33) * 6
		  + (blue + 25) / 0x33;
    }
    return 0;
}

/*
 * Convert the attributes of a vterm cell into an attribute index.
 */
    static int
cell2attr(VTermScreenCell *cell)
{
    int attr = 0;

    if (cell->attrs.bold)
	attr |= HL_BOLD;
    if (cell->attrs.underline)
	attr |= HL_UNDERLINE;
    if (cell->attrs.italic)
	attr |= HL_ITALIC;
    if (cell->attrs.strike)
	attr |= HL_STANDOUT;
    if (cell->attrs.reverse)
	attr |= HL_INVERSE;

#ifdef FEAT_GUI
    if (gui.in_use)
    {
	guicolor_T fg, bg;

	fg = gui_mch_get_rgb_color(cell->fg.red, cell->fg.green, cell->fg.blue);
	bg = gui_mch_get_rgb_color(cell->bg.red, cell->bg.green, cell->bg.blue);
	return get_gui_attr_idx(attr, fg, bg);
    }
    else
#endif
#ifdef FEAT_TERMGUICOLORS
    if (p_tgc)
    {
	guicolor_T fg, bg;

	fg = gui_get_rgb_color_cmn(cell->fg.red, cell->fg.green, cell->fg.blue);
	bg = gui_get_rgb_color_cmn(cell->bg.red, cell->bg.green, cell->bg.blue);

	return get_tgc_attr_idx(attr, fg, bg);
    }
    else
#endif
    {
	int bold = MAYBE;
	int fg = color2index(&cell->fg, TRUE, &bold);
	int bg = color2index(&cell->bg, FALSE, &bold);

	/* with 8 colors set the bold attribute to get a bright foreground */
	if (bold == TRUE)
	    attr |= HL_BOLD;
	return get_cterm_attr_idx(attr, fg, bg);
    }
    return 0;
}

/*
 * Called to update the window that contains a terminal.
 * Returns FAIL when there is no terminal running in this window.
 */
    int
term_update_window(win_T *wp)
{
    term_T	*term = wp->w_buffer->b_term;
    VTerm	*vterm;
    VTermScreen *screen;
    VTermState	*state;
    VTermPos	pos;

    if (term == NULL || term->tl_vterm == NULL || term->tl_terminal_mode)
	return FAIL;

    vterm = term->tl_vterm;
    screen = vterm_obtain_screen(vterm);
    state = vterm_obtain_state(vterm);

    /*
     * If the window was resized a redraw will be triggered and we get here.
     * Adjust the size of the vterm unless 'termsize' specifies a fixed size.
     */
    if ((!term->tl_rows_fixed && term->tl_rows != wp->w_height)
	    || (!term->tl_cols_fixed && term->tl_cols != wp->w_width))
    {
	int	rows = term->tl_rows_fixed ? term->tl_rows : wp->w_height;
	int	cols = term->tl_cols_fixed ? term->tl_cols : wp->w_width;
	win_T	*twp;

	FOR_ALL_WINDOWS(twp)
	{
	    /* When more than one window shows the same terminal, use the
	     * smallest size. */
	    if (twp->w_buffer == term->tl_buffer)
	    {
		if (!term->tl_rows_fixed && rows > twp->w_height)
		    rows = twp->w_height;
		if (!term->tl_cols_fixed && cols > twp->w_width)
		    cols = twp->w_width;
	    }
	}

	vterm_set_size(vterm, rows, cols);
	ch_logn(term->tl_job->jv_channel, "Resizing terminal to %d lines",
									 rows);
	term_report_winsize(term, rows, cols);
    }

    /* The cursor may have been moved when resizing. */
    vterm_state_get_cursorpos(state, &pos);
    position_cursor(wp, &pos);

    /* TODO: Only redraw what changed. */
    for (pos.row = 0; pos.row < wp->w_height; ++pos.row)
    {
	int off = screen_get_current_line_off();
	int max_col = MIN(wp->w_width, term->tl_cols);

	if (pos.row < term->tl_rows)
	{
	    for (pos.col = 0; pos.col < max_col; )
	    {
		VTermScreenCell cell;
		int		c;

		if (vterm_screen_get_cell(screen, pos, &cell) == 0)
		    vim_memset(&cell, 0, sizeof(cell));

		/* TODO: composing chars */
		c = cell.chars[0];
		if (c == NUL)
		{
		    ScreenLines[off] = ' ';
#if defined(FEAT_MBYTE)
		    if (enc_utf8)
			ScreenLinesUC[off] = NUL;
#endif
		}
		else
		{
#if defined(FEAT_MBYTE)
		    if (enc_utf8 && c >= 0x80)
		    {
			ScreenLines[off] = ' ';
			ScreenLinesUC[off] = c;
		    }
		    else
		    {
			ScreenLines[off] = c;
			if (enc_utf8)
			    ScreenLinesUC[off] = NUL;
		    }
#else
		    ScreenLines[off] = c;
#endif
		}
		ScreenAttrs[off] = cell2attr(&cell);

		++pos.col;
		++off;
		if (cell.width == 2)
		{
		    ScreenLines[off] = NUL;
#if defined(FEAT_MBYTE)
		    if (enc_utf8)
			ScreenLinesUC[off] = NUL;
#endif
		    ++pos.col;
		    ++off;
		}
	    }
	}
	else
	    pos.col = 0;

	screen_line(wp->w_winrow + pos.row, wp->w_wincol,
						  pos.col, wp->w_width, FALSE);
    }

    return OK;
}

/*
 * Return TRUE if "wp" is a terminal window where the job has finished.
 */
    int
term_is_finished(buf_T *buf)
{
    return buf->b_term != NULL && buf->b_term->tl_vterm == NULL;
}

/*
 * Return TRUE if "wp" is a terminal window where the job has finished or we
 * are in Terminal-Normal mode.
 */
    int
term_show_buffer(buf_T *buf)
{
    term_T *term = buf->b_term;

    return term != NULL && (term->tl_vterm == NULL || term->tl_terminal_mode);
}

/*
 * The current buffer is going to be changed.  If there is terminal
 * highlighting remove it now.
 */
    void
term_change_in_curbuf(void)
{
    term_T *term = curbuf->b_term;

    if (term_is_finished(curbuf) && term->tl_scrollback.ga_len > 0)
    {
	free_scrollback(term);
	redraw_buf_later(term->tl_buffer, NOT_VALID);

	/* The buffer is now like a normal buffer, it cannot be easily
	 * abandoned when changed. */
	set_string_option_direct((char_u *)"buftype", -1,
					  (char_u *)"", OPT_FREE|OPT_LOCAL, 0);
    }
}

/*
 * Get the screen attribute for a position in the buffer.
 */
    int
term_get_attr(buf_T *buf, linenr_T lnum, int col)
{
    term_T *term = buf->b_term;
    sb_line_T *line;

    if (lnum > term->tl_scrollback.ga_len)
	return 0;
    line = (sb_line_T *)term->tl_scrollback.ga_data + lnum - 1;
    if (col >= line->sb_cols)
	return 0;
    return cell2attr(line->sb_cells + col);
}

/*
 * Set job options common for Unix and MS-Windows.
 */
    static void
setup_job_options(jobopt_T *opt, int rows, int cols)
{
    clear_job_options(opt);
    opt->jo_mode = MODE_RAW;
    opt->jo_out_mode = MODE_RAW;
    opt->jo_err_mode = MODE_RAW;
    opt->jo_set = JO_MODE | JO_OUT_MODE | JO_ERR_MODE;

    opt->jo_io[PART_OUT] = JIO_BUFFER;
    opt->jo_io[PART_ERR] = JIO_BUFFER;
    opt->jo_set |= JO_OUT_IO + JO_ERR_IO;

    opt->jo_modifiable[PART_OUT] = 0;
    opt->jo_modifiable[PART_ERR] = 0;
    opt->jo_set |= JO_OUT_MODIFIABLE + JO_ERR_MODIFIABLE;

    opt->jo_io_buf[PART_OUT] = curbuf->b_fnum;
    opt->jo_io_buf[PART_ERR] = curbuf->b_fnum;
    opt->jo_pty = TRUE;
    opt->jo_set |= JO_OUT_BUF + JO_ERR_BUF;

    opt->jo_term_rows = rows;
    opt->jo_term_cols = cols;
}

/*
 * Create a new vterm and initialize it.
 */
    static void
create_vterm(term_T *term, int rows, int cols)
{
    VTerm	    *vterm;
    VTermScreen	    *screen;

    vterm = vterm_new(rows, cols);
    term->tl_vterm = vterm;
    screen = vterm_obtain_screen(vterm);
    vterm_screen_set_callbacks(screen, &screen_callbacks, term);
    /* TODO: depends on 'encoding'. */
    vterm_set_utf8(vterm, 1);

    /* Vterm uses a default black background.  Set it to white when
     * 'background' is "light". */
    if (*p_bg == 'l')
    {
	VTermColor	fg, bg;

	fg.red = fg.green = fg.blue = 0;
	bg.red = bg.green = bg.blue = 255;
	vterm_state_set_default_colors(vterm_obtain_state(vterm), &fg, &bg);
    }

    /* Required to initialize most things. */
    vterm_screen_reset(screen, 1 /* hard */);
}

/*
 * Return the text to show for the buffer name and status.
 */
    char_u *
term_get_status_text(term_T *term)
{
    if (term->tl_status_text == NULL)
    {
	char_u *txt;
	size_t len;

	if (term->tl_terminal_mode)
	{
	    if (term_job_running(term))
		txt = (char_u *)_("Terminal");
	    else
		txt = (char_u *)_("Terminal-finished");
	}
	else if (term->tl_title != NULL)
	    txt = term->tl_title;
	else if (term_job_running(term))
	    txt = (char_u *)_("running");
	else
	    txt = (char_u *)_("finished");
	len = 9 + STRLEN(term->tl_buffer->b_fname) + STRLEN(txt);
	term->tl_status_text = alloc((int)len);
	if (term->tl_status_text != NULL)
	    vim_snprintf((char *)term->tl_status_text, len, "%s [%s]",
						term->tl_buffer->b_fname, txt);
    }
    return term->tl_status_text;
}

/*
 * Mark references in jobs of terminals.
 */
    int
set_ref_in_term(int copyID)
{
    int		abort = FALSE;
    term_T	*term;
    typval_T	tv;

    for (term = first_term; term != NULL; term = term->tl_next)
	if (term->tl_job != NULL)
	{
	    tv.v_type = VAR_JOB;
	    tv.vval.v_job = term->tl_job;
	    abort = abort || set_ref_in_item(&tv, copyID, NULL, NULL);
	}
    return abort;
}

/*
 * Get the buffer from the first argument in "argvars".
 * Returns NULL when the buffer is not for a terminal window.
 */
    static buf_T *
term_get_buf(typval_T *argvars)
{
    buf_T *buf;

    (void)get_tv_number(&argvars[0]);	    /* issue errmsg if type error */
    ++emsg_off;
    buf = get_buf_tv(&argvars[0], FALSE);
    --emsg_off;
    if (buf == NULL || buf->b_term == NULL)
	return NULL;
    return buf;
}

/*
 * "term_getattr(attr, name)" function
 */
    void
f_term_getattr(typval_T *argvars, typval_T *rettv)
{
    int	    attr;
    size_t  i;
    char_u  *name;

    static struct {
	char	    *name;
	int	    attr;
    } attrs[] = {
	{"bold",      HL_BOLD},
	{"italic",    HL_ITALIC},
	{"underline", HL_UNDERLINE},
	{"strike",    HL_STANDOUT},
	{"reverse",   HL_INVERSE},
    };

    attr = get_tv_number(&argvars[0]);
    name = get_tv_string_chk(&argvars[1]);
    if (name == NULL)
	return;

    for (i = 0; i < sizeof(attrs)/sizeof(attrs[0]); ++i)
	if (STRCMP(name, attrs[i].name) == 0)
	{
	    rettv->vval.v_number = (attr & attrs[i].attr) != 0 ? 1 : 0;
	    break;
	}
}

/*
 * "term_getcursor(buf)" function
 */
    void
f_term_getcursor(typval_T *argvars, typval_T *rettv)
{
    buf_T	*buf = term_get_buf(argvars);
    list_T	*l;

    if (rettv_list_alloc(rettv) == FAIL)
	return;
    if (buf == NULL)
	return;

    l = rettv->vval.v_list;
    list_append_number(l, buf->b_term->tl_cursor_pos.row + 1);
    list_append_number(l, buf->b_term->tl_cursor_pos.col + 1);
    list_append_number(l, buf->b_term->tl_cursor_visible);
}

/*
 * "term_getjob(buf)" function
 */
    void
f_term_getjob(typval_T *argvars, typval_T *rettv)
{
    buf_T	*buf = term_get_buf(argvars);

    rettv->v_type = VAR_JOB;
    rettv->vval.v_job = NULL;
    if (buf == NULL)
	return;

    rettv->vval.v_job = buf->b_term->tl_job;
    if (rettv->vval.v_job != NULL)
	++rettv->vval.v_job->jv_refcount;
}

    static int
get_row_number(typval_T *tv, term_T *term)
{
    if (tv->v_type == VAR_STRING
	    && tv->vval.v_string != NULL
	    && STRCMP(tv->vval.v_string, ".") == 0)
	return term->tl_cursor_pos.row;
    return (int)get_tv_number(tv) - 1;
}

/*
 * "term_getline(buf, row)" function
 */
    void
f_term_getline(typval_T *argvars, typval_T *rettv)
{
    buf_T	    *buf = term_get_buf(argvars);
    term_T	    *term;
    int		    row;

    rettv->v_type = VAR_STRING;
    if (buf == NULL)
	return;
    term = buf->b_term;
    row = get_row_number(&argvars[1], term);

    if (term->tl_vterm == NULL)
    {
	linenr_T lnum = row + term->tl_scrollback_scrolled + 1;

	/* vterm is finished, get the text from the buffer */
	if (lnum > 0 && lnum <= buf->b_ml.ml_line_count)
	    rettv->vval.v_string = vim_strsave(ml_get_buf(buf, lnum, FALSE));
    }
    else
    {
	VTermScreen	*screen = vterm_obtain_screen(term->tl_vterm);
	VTermRect	rect;
	int		len;
	char_u		*p;

	if (row < 0 || row >= term->tl_rows)
	    return;
	len = term->tl_cols * MB_MAXBYTES + 1;
	p = alloc(len);
	if (p == NULL)
	    return;
	rettv->vval.v_string = p;

	rect.start_col = 0;
	rect.end_col = term->tl_cols;
	rect.start_row = row;
	rect.end_row = row + 1;
	p[vterm_screen_get_text(screen, (char *)p, len, rect)] = NUL;
    }
}

/*
 * "term_getsize(buf)" function
 */
    void
f_term_getsize(typval_T *argvars, typval_T *rettv)
{
    buf_T	*buf = term_get_buf(argvars);
    list_T	*l;

    if (rettv_list_alloc(rettv) == FAIL)
	return;
    if (buf == NULL)
	return;

    l = rettv->vval.v_list;
    list_append_number(l, buf->b_term->tl_rows);
    list_append_number(l, buf->b_term->tl_cols);
}

/*
 * "term_getstatus(buf)" function
 */
    void
f_term_getstatus(typval_T *argvars, typval_T *rettv)
{
    buf_T	*buf = term_get_buf(argvars);
    term_T	*term;
    char_u	val[100];

    rettv->v_type = VAR_STRING;
    if (buf == NULL)
	return;
    term = buf->b_term;

    if (term_job_running(term))
	STRCPY(val, "running");
    else
	STRCPY(val, "finished");
    if (term->tl_terminal_mode)
	STRCAT(val, ",terminal");
    rettv->vval.v_string = vim_strsave(val);
}

/*
 * "term_gettitle(buf)" function
 */
    void
f_term_gettitle(typval_T *argvars, typval_T *rettv)
{
    buf_T	*buf = term_get_buf(argvars);

    rettv->v_type = VAR_STRING;
    if (buf == NULL)
	return;

    if (buf->b_term->tl_title != NULL)
	rettv->vval.v_string = vim_strsave(buf->b_term->tl_title);
}

/*
 * "term_list()" function
 */
    void
f_term_list(typval_T *argvars UNUSED, typval_T *rettv)
{
    term_T	*tp;
    list_T	*l;

    if (rettv_list_alloc(rettv) == FAIL || first_term == NULL)
	return;

    l = rettv->vval.v_list;
    for (tp = first_term; tp != NULL; tp = tp->tl_next)
	if (tp != NULL && tp->tl_buffer != NULL)
	    if (list_append_number(l,
				   (varnumber_T)tp->tl_buffer->b_fnum) == FAIL)
		return;
}

/*
 * "term_scrape(buf, row)" function
 */
    void
f_term_scrape(typval_T *argvars, typval_T *rettv)
{
    buf_T	    *buf = term_get_buf(argvars);
    VTermScreen	    *screen = NULL;
    VTermPos	    pos;
    list_T	    *l;
    term_T	    *term;

    if (rettv_list_alloc(rettv) == FAIL)
	return;
    if (buf == NULL)
	return;
    term = buf->b_term;
    if (term->tl_vterm != NULL)
	screen = vterm_obtain_screen(term->tl_vterm);

    l = rettv->vval.v_list;
    pos.row = get_row_number(&argvars[1], term);
    for (pos.col = 0; pos.col < term->tl_cols; )
    {
	dict_T		*dcell;
	VTermScreenCell cell;
	char_u		rgb[8];
	char_u		mbs[MB_MAXBYTES * VTERM_MAX_CHARS_PER_CELL + 1];
	int		off = 0;
	int		i;

	if (screen == NULL)
	{
	    linenr_T lnum = pos.row + term->tl_scrollback_scrolled;
	    sb_line_T *line;

	    /* vterm has finished, get the cell from scrollback */
	    if (lnum < 0 || lnum >= term->tl_scrollback.ga_len)
		break;
	    line = (sb_line_T *)term->tl_scrollback.ga_data + lnum;
	    if (pos.col >= line->sb_cols)
		break;
	    cell = line->sb_cells[pos.col];
	}
	else if (vterm_screen_get_cell(screen, pos, &cell) == 0)
	    break;
	dcell = dict_alloc();
	list_append_dict(l, dcell);

	for (i = 0; i < VTERM_MAX_CHARS_PER_CELL; ++i)
	{
	    if (cell.chars[i] == 0)
		break;
	    off += (*utf_char2bytes)((int)cell.chars[i], mbs + off);
	}
	mbs[off] = NUL;
	dict_add_nr_str(dcell, "chars", 0, mbs);

	vim_snprintf((char *)rgb, 8, "#%02x%02x%02x",
				     cell.fg.red, cell.fg.green, cell.fg.blue);
	dict_add_nr_str(dcell, "fg", 0, rgb);
	vim_snprintf((char *)rgb, 8, "#%02x%02x%02x",
				     cell.bg.red, cell.bg.green, cell.bg.blue);
	dict_add_nr_str(dcell, "bg", 0, rgb);

	dict_add_nr_str(dcell, "attr", cell2attr(&cell), NULL);
	dict_add_nr_str(dcell, "width", cell.width, NULL);

	++pos.col;
	if (cell.width == 2)
	    ++pos.col;
    }
}

/*
 * "term_sendkeys(buf, keys)" function
 */
    void
f_term_sendkeys(typval_T *argvars, typval_T *rettv)
{
    buf_T	*buf = term_get_buf(argvars);
    char_u	*msg;
    term_T	*term;

    rettv->v_type = VAR_UNKNOWN;
    if (buf == NULL)
	return;

    msg = get_tv_string_chk(&argvars[1]);
    if (msg == NULL)
	return;
    term = buf->b_term;
    if (term->tl_vterm == NULL)
	return;

    while (*msg != NUL)
    {
	send_keys_to_term(term, PTR2CHAR(msg), FALSE);
	msg += MB_PTR2LEN(msg);
    }

    if (!term->tl_terminal_mode)
    {
	/* TODO: only update once in a while. */
	update_screen(0);
	if (buf == curbuf)
	    update_cursor(term, TRUE);
    }
}

/*
 * "term_start(command, options)" function
 */
    void
f_term_start(typval_T *argvars, typval_T *rettv)
{
    char_u	*cmd = get_tv_string_chk(&argvars[0]);
    exarg_T	ea;

    if (cmd == NULL)
	return;
    ea.arg = cmd;
    ex_terminal(&ea);

    if (curbuf->b_term != NULL)
	rettv->vval.v_number = curbuf->b_fnum;
}

/*
 * "term_wait" function
 */
    void
f_term_wait(typval_T *argvars, typval_T *rettv UNUSED)
{
    buf_T	*buf = term_get_buf(argvars);

    if (buf == NULL)
	return;

    /* Get the job status, this will detect a job that finished. */
    if (buf->b_term->tl_job != NULL)
	(void)job_status(buf->b_term->tl_job);

    /* Check for any pending channel I/O. */
    vpeekc_any();
    ui_delay(10L, FALSE);

    /* Flushing messages on channels is hopefully sufficient.
     * TODO: is there a better way? */
    parse_queued_messages();
}

# ifdef WIN3264

/**************************************
 * 2. MS-Windows implementation.
 */

#define WINPTY_SPAWN_FLAG_AUTO_SHUTDOWN 1ul
#define WINPTY_SPAWN_FLAG_EXIT_AFTER_SHUTDOWN 2ull

void* (*winpty_config_new)(UINT64, void*);
void* (*winpty_open)(void*, void*);
void* (*winpty_spawn_config_new)(UINT64, void*, LPCWSTR, void*, void*, void*);
BOOL (*winpty_spawn)(void*, void*, HANDLE*, HANDLE*, DWORD*, void*);
void (*winpty_config_set_initial_size)(void*, int, int);
LPCWSTR (*winpty_conin_name)(void*);
LPCWSTR (*winpty_conout_name)(void*);
LPCWSTR (*winpty_conerr_name)(void*);
void (*winpty_free)(void*);
void (*winpty_config_free)(void*);
void (*winpty_spawn_config_free)(void*);
void (*winpty_error_free)(void*);
LPCWSTR (*winpty_error_msg)(void*);
BOOL (*winpty_set_size)(void*, int, int, void*);

#define WINPTY_DLL "winpty.dll"

static HINSTANCE hWinPtyDLL = NULL;

    int
dyn_winpty_init(void)
{
    int i;
    static struct
    {
	char	    *name;
	FARPROC	    *ptr;
    } winpty_entry[] =
    {
	{"winpty_conerr_name", (FARPROC*)&winpty_conerr_name},
	{"winpty_config_free", (FARPROC*)&winpty_config_free},
	{"winpty_config_new", (FARPROC*)&winpty_config_new},
	{"winpty_config_set_initial_size", (FARPROC*)&winpty_config_set_initial_size},
	{"winpty_conin_name", (FARPROC*)&winpty_conin_name},
	{"winpty_conout_name", (FARPROC*)&winpty_conout_name},
	{"winpty_error_free", (FARPROC*)&winpty_error_free},
	{"winpty_free", (FARPROC*)&winpty_free},
	{"winpty_open", (FARPROC*)&winpty_open},
	{"winpty_spawn", (FARPROC*)&winpty_spawn},
	{"winpty_spawn_config_free", (FARPROC*)&winpty_spawn_config_free},
	{"winpty_spawn_config_new", (FARPROC*)&winpty_spawn_config_new},
	{"winpty_error_msg", (FARPROC*)&winpty_error_msg},
	{"winpty_set_size", (FARPROC*)&winpty_set_size},
	{NULL, NULL}
    };

    /* No need to initialize twice. */
    if (hWinPtyDLL)
	return 1;
    /* Load winpty.dll */
    hWinPtyDLL = vimLoadLib(WINPTY_DLL);
    if (!hWinPtyDLL)
    {
	EMSG2(_(e_loadlib), WINPTY_DLL);
	return 0;
    }
    for (i = 0; winpty_entry[i].name != NULL
					 && winpty_entry[i].ptr != NULL; ++i)
    {
	if ((*winpty_entry[i].ptr = (FARPROC)GetProcAddress(hWinPtyDLL,
					      winpty_entry[i].name)) == NULL)
	{
	    EMSG2(_(e_loadfunc), winpty_entry[i].name);
	    return 0;
	}
    }

    return 1;
}

/*
 * Create a new terminal of "rows" by "cols" cells.
 * Store a reference in "term".
 * Return OK or FAIL.
 */
    static int
term_and_job_init(term_T *term, int rows, int cols, char_u *cmd)
{
    WCHAR	    *p;
    channel_T	    *channel = NULL;
    job_T	    *job = NULL;
    jobopt_T	    opt;
    DWORD	    error;
    HANDLE	    jo = NULL, child_process_handle, child_thread_handle;
    void	    *winpty_err;
    void	    *spawn_config = NULL;

    if (!dyn_winpty_init())
	return FAIL;

    p = enc_to_utf16(cmd, NULL);
    if (p == NULL)
	return FAIL;

    job = job_alloc();
    if (job == NULL)
	goto failed;

    channel = add_channel();
    if (channel == NULL)
	goto failed;

    term->tl_winpty_config = winpty_config_new(0, &winpty_err);
    if (term->tl_winpty_config == NULL)
	goto failed;

    winpty_config_set_initial_size(term->tl_winpty_config, cols, rows);
    term->tl_winpty = winpty_open(term->tl_winpty_config, &winpty_err);
    if (term->tl_winpty == NULL)
	goto failed;

    spawn_config = winpty_spawn_config_new(
	    WINPTY_SPAWN_FLAG_AUTO_SHUTDOWN |
		WINPTY_SPAWN_FLAG_EXIT_AFTER_SHUTDOWN,
	    NULL,
	    p,
	    NULL,
	    NULL,
	    &winpty_err);
    if (spawn_config == NULL)
	goto failed;

    channel = add_channel();
    if (channel == NULL)
	goto failed;

    job = job_alloc();
    if (job == NULL)
	goto failed;

    if (!winpty_spawn(term->tl_winpty, spawn_config, &child_process_handle,
	    &child_thread_handle, &error, &winpty_err))
	goto failed;

    channel_set_pipes(channel,
	(sock_T) CreateFileW(
	    winpty_conin_name(term->tl_winpty),
	    GENERIC_WRITE, 0, NULL,
	    OPEN_EXISTING, 0, NULL),
	(sock_T) CreateFileW(
	    winpty_conout_name(term->tl_winpty),
	    GENERIC_READ, 0, NULL,
	    OPEN_EXISTING, 0, NULL),
	(sock_T) CreateFileW(
	    winpty_conerr_name(term->tl_winpty),
	    GENERIC_READ, 0, NULL,
	    OPEN_EXISTING, 0, NULL));

    jo = CreateJobObject(NULL, NULL);
    if (jo == NULL)
	goto failed;

    if (!AssignProcessToJobObject(jo, child_process_handle))
    {
	/* Failed, switch the way to terminate process with TerminateProcess. */
	CloseHandle(jo);
	jo = NULL;
    }

    winpty_spawn_config_free(spawn_config);
    vim_free(p);

    create_vterm(term, rows, cols);

    setup_job_options(&opt, rows, cols);
    channel_set_job(channel, job, &opt);

    job->jv_channel = channel;
    job->jv_proc_info.hProcess = child_process_handle;
    job->jv_proc_info.dwProcessId = GetProcessId(child_process_handle);
    job->jv_job_object = jo;
    job->jv_status = JOB_STARTED;
    ++job->jv_refcount;
    term->tl_job = job;

    return OK;

failed:
    if (spawn_config != NULL)
	winpty_spawn_config_free(spawn_config);
    vim_free(p);
    if (channel != NULL)
	channel_clear(channel);
    if (job != NULL)
    {
	job->jv_channel = NULL;
	job_cleanup(job);
    }
    term->tl_job = NULL;
    if (jo != NULL)
	CloseHandle(jo);
    if (term->tl_winpty != NULL)
	winpty_free(term->tl_winpty);
    term->tl_winpty = NULL;
    if (term->tl_winpty_config != NULL)
	winpty_config_free(term->tl_winpty_config);
    term->tl_winpty_config = NULL;
    if (winpty_err != NULL)
    {
	char_u *msg = utf16_to_enc(
				(short_u *)winpty_error_msg(winpty_err), NULL);

	EMSG(msg);
	winpty_error_free(winpty_err);
    }
    return FAIL;
}

/*
 * Free the terminal emulator part of "term".
 */
    static void
term_free_vterm(term_T *term)
{
    if (term->tl_winpty != NULL)
	winpty_free(term->tl_winpty);
    term->tl_winpty = NULL;
    if (term->tl_winpty_config != NULL)
	winpty_config_free(term->tl_winpty_config);
    term->tl_winpty_config = NULL;
    if (term->tl_vterm != NULL)
	vterm_free(term->tl_vterm);
    term->tl_vterm = NULL;
}

/*
 * Request size to terminal.
 */
    static void
term_report_winsize(term_T *term, int rows, int cols)
{
    winpty_set_size(term->tl_winpty, cols, rows, NULL);
}

# else

/**************************************
 * 3. Unix-like implementation.
 */

/*
 * Create a new terminal of "rows" by "cols" cells.
 * Start job for "cmd".
 * Store the pointers in "term".
 * Return OK or FAIL.
 */
    static int
term_and_job_init(term_T *term, int rows, int cols, char_u *cmd)
{
    typval_T	argvars[2];
    jobopt_T	opt;

    create_vterm(term, rows, cols);

    argvars[0].v_type = VAR_STRING;
    argvars[0].vval.v_string = cmd;
    setup_job_options(&opt, rows, cols);
    term->tl_job = job_start(argvars, &opt);
    if (term->tl_job != NULL)
	++term->tl_job->jv_refcount;

    return term->tl_job != NULL
	&& term->tl_job->jv_channel != NULL
	&& term->tl_job->jv_status != JOB_FAILED ? OK : FAIL;
}

/*
 * Free the terminal emulator part of "term".
 */
    static void
term_free_vterm(term_T *term)
{
    if (term->tl_vterm != NULL)
	vterm_free(term->tl_vterm);
    term->tl_vterm = NULL;
}

/*
 * Request size to terminal.
 */
    static void
term_report_winsize(term_T *term, int rows, int cols)
{
    /* Use an ioctl() to report the new window size to the job. */
    if (term->tl_job != NULL && term->tl_job->jv_channel != NULL)
    {
	int fd = -1;
	int part;

	for (part = PART_OUT; part < PART_COUNT; ++part)
	{
	    fd = term->tl_job->jv_channel->ch_part[part].ch_fd;
	    if (isatty(fd))
		break;
	}
	if (part < PART_COUNT && mch_report_winsize(fd, rows, cols) == OK)
	    mch_stop_job(term->tl_job, (char_u *)"winch");
    }
}

# endif

#endif /* FEAT_TERMINAL */