text: /* $OpenBSD$ */
  
  /*
   * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
   *
   * Permission to use, copy, modify, and distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
   * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
   * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
   * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
   * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   */
  
  #include <sys/types.h>
  #include <sys/ioctl.h>
  
  #include <ctype.h>
  #include <errno.h>
  #include <fcntl.h>
  #include <fnmatch.h>
  #include <regex.h>
  #include <signal.h>
  #include <stdint.h>
  #include <stdlib.h>
  #include <string.h>
  #include <time.h>
  #include <unistd.h>
  
  #include "tmux.h"
  
  /*
   * Each window is attached to a number of panes, each of which is a pty. This
   * file contains code to handle them.
   *
   * A pane has two buffers attached, these are filled and emptied by the main
   * server poll loop. Output data is received from pty's in screen format,
   * translated and returned as a series of escape sequences and strings via
   * input_parse (in input.c). Input data is received as key codes and written
   * directly via input_key.
   *
   * Each pane also has a "virtual" screen (screen.c) which contains the current
   * state and is redisplayed when the window is reattached to a client.
   *
   * Windows are stored directly on a global array and wrapped in any number of
   * winlink structs to be linked onto local session RB trees. A reference count
   * is maintained and a window removed from the global list and destroyed when
   * it reaches zero.
   */
  
  /* Global window list. */
  struct windows windows;
  
  /* Global panes tree. */
  struct window_pane_tree all_window_panes;
  static u_int	next_window_pane_id;
  static u_int	next_window_id;
  static u_int	next_active_point;
  
  /* List of window modes. */
  const struct window_mode *all_window_modes[] = {
  	&window_buffer_mode,
  	&window_client_mode,
  	&window_clock_mode,
  	&window_copy_mode,
  	&window_tree_mode,
  	&window_view_mode,
  	NULL
  };
  
  struct window_pane_input_data {
  	struct cmdq_item	*item;
  	u_int			 wp;
  };
  
  static struct window_pane *window_pane_create(struct window *, u_int, u_int,
  		    u_int);
  static void	window_pane_destroy(struct window_pane *);
  
  RB_GENERATE(windows, window, entry, window_cmp);
  RB_GENERATE(winlinks, winlink, entry, winlink_cmp);
  RB_GENERATE(window_pane_tree, window_pane, tree_entry, window_pane_cmp);
  
  int
  window_cmp(struct window *w1, struct window *w2)
  {
  	return (w1->id - w2->id);
  }
  
  int
  winlink_cmp(struct winlink *wl1, struct winlink *wl2)
  {
  	return (wl1->idx - wl2->idx);
  }
  
  int
  window_pane_cmp(struct window_pane *wp1, struct window_pane *wp2)
  {
  	return (wp1->id - wp2->id);
  }
  
  struct winlink *
  winlink_find_by_window(struct winlinks *wwl, struct window *w)
  {
  	struct winlink	*wl;
  
  	RB_FOREACH(wl, winlinks, wwl) {
  		if (wl->window == w)
  			return (wl);
  	}
  
  	return (NULL);
  }
  
  struct winlink *
  winlink_find_by_index(struct winlinks *wwl, int idx)
  {
  	struct winlink	wl;
  
  	if (idx < 0)
  		fatalx("bad index");
  
  	wl.idx = idx;
  	return (RB_FIND(winlinks, wwl, &wl));
  }
  
  struct winlink *
  winlink_find_by_window_id(struct winlinks *wwl, u_int id)
  {
  	struct winlink *wl;
  
  	RB_FOREACH(wl, winlinks, wwl) {
  		if (wl->window->id == id)
  			return (wl);
  	}
  	return (NULL);
  }
  
  static int
  winlink_next_index(struct winlinks *wwl, int idx)
  {
  	int	i;
  
  	i = idx;
  	do {
  		if (winlink_find_by_index(wwl, i) == NULL)
  			return (i);
  		if (i == INT_MAX)
  			i = 0;
  		else
  			i++;
  	} while (i != idx);
  	return (-1);
  }
  
  u_int
  winlink_count(struct winlinks *wwl)
  {
  	struct winlink	*wl;
  	u_int		 n;
  
  	n = 0;
  	RB_FOREACH(wl, winlinks, wwl)
  		n++;
  
  	return (n);
  }
  
  struct winlink *
  winlink_add(struct winlinks *wwl, int idx)
  {
  	struct winlink	*wl;
  
  	if (idx < 0) {
  		if ((idx = winlink_next_index(wwl, -idx - 1)) == -1)
  			return (NULL);
  	} else if (winlink_find_by_index(wwl, idx) != NULL)
  		return (NULL);
  
  	wl = xcalloc(1, sizeof *wl);
  	wl->idx = idx;
  	RB_INSERT(winlinks, wwl, wl);
  
  	return (wl);
  }
  
  void
  winlink_set_window(struct winlink *wl, struct window *w)
  {
  	if (wl->window != NULL) {
  		TAILQ_REMOVE(&wl->window->winlinks, wl, wentry);
  		window_remove_ref(wl->window, __func__);
  	}
  	TAILQ_INSERT_TAIL(&w->winlinks, wl, wentry);
  	wl->window = w;
  	window_add_ref(w, __func__);
  }
  
  void
  winlink_remove(struct winlinks *wwl, struct winlink *wl)
  {
  	struct window	*w = wl->window;
  
  	if (w != NULL) {
  		TAILQ_REMOVE(&w->winlinks, wl, wentry);
  		window_remove_ref(w, __func__);
  	}
  
  	RB_REMOVE(winlinks, wwl, wl);
  	free(wl);
  }
  
  struct winlink *
  winlink_next(struct winlink *wl)
  {
  	return (RB_NEXT(winlinks, wwl, wl));
  }
  
  struct winlink *
  winlink_previous(struct winlink *wl)
  {
  	return (RB_PREV(winlinks, wwl, wl));
  }
  
  struct winlink *
  winlink_next_by_number(struct winlink *wl, struct session *s, int n)
  {
  	for (; n > 0; n--) {
  		if ((wl = RB_NEXT(winlinks, wwl, wl)) == NULL)
  			wl = RB_MIN(winlinks, &s->windows);
  	}
  
  	return (wl);
  }
  
  struct winlink *
  winlink_previous_by_number(struct winlink *wl, struct session *s, int n)
  {
  	for (; n > 0; n--) {
  		if ((wl = RB_PREV(winlinks, wwl, wl)) == NULL)
  			wl = RB_MAX(winlinks, &s->windows);
  	}
  
  	return (wl);
  }
  
  void
  winlink_stack_push(struct winlink_stack *stack, struct winlink *wl)
  {
  	if (wl == NULL)
  		return;
  
  	winlink_stack_remove(stack, wl);
  	TAILQ_INSERT_HEAD(stack, wl, sentry);
  }
  
  void
  winlink_stack_remove(struct winlink_stack *stack, struct winlink *wl)
  {
  	struct winlink	*wl2;
  
  	if (wl == NULL)
  		return;
  
  	TAILQ_FOREACH(wl2, stack, sentry) {
  		if (wl2 == wl) {
  			TAILQ_REMOVE(stack, wl, sentry);
  			return;
  		}
  	}
  }
  
  struct window *
  window_find_by_id_str(const char *s)
  {
  	const char	*errstr;
  	u_int		 id;
  
  	if (*s != '@')
  		return (NULL);
  
  	id = strtonum(s + 1, 0, UINT_MAX, &errstr);
  	if (errstr != NULL)
  		return (NULL);
  	return (window_find_by_id(id));
  }
  
  struct window *
  window_find_by_id(u_int id)
  {
  	struct window	w;
  
  	w.id = id;
  	return (RB_FIND(windows, &windows, &w));
  }
  
  void
  window_update_activity(struct window *w)
  {
  	gettimeofday(&w->activity_time, NULL);
  	alerts_queue(w, WINDOW_ACTIVITY);
  }
  
  struct window *
  window_create(u_int sx, u_int sy)
  {
  	struct window	*w;
  
  	w = xcalloc(1, sizeof *w);
  	w->name = NULL;
  	w->flags = 0;
  
  	TAILQ_INIT(&w->panes);
  	w->active = NULL;
  
  	w->lastlayout = -1;
  	w->layout_root = NULL;
  
  	w->sx = sx;
  	w->sy = sy;
  
  	w->options = options_create(global_w_options);
  
  	w->references = 0;
  	TAILQ_INIT(&w->winlinks);
  
  	w->id = next_window_id++;
  	RB_INSERT(windows, &windows, w);
  
  	window_update_activity(w);
  
  	return (w);
  }
  
  static void
  window_destroy(struct window *w)
  {
  	log_debug("window @%u destroyed (%d references)", w->id, w->references);
  
  	RB_REMOVE(windows, &windows, w);
  
  	if (w->layout_root != NULL)
  		layout_free_cell(w->layout_root);
  	if (w->saved_layout_root != NULL)
  		layout_free_cell(w->saved_layout_root);
  	free(w->old_layout);
  
  	window_destroy_panes(w);
  
  	if (event_initialized(&w->name_event))
  		evtimer_del(&w->name_event);
  
  	if (event_initialized(&w->alerts_timer))
  		evtimer_del(&w->alerts_timer);
  	if (event_initialized(&w->offset_timer))
  		event_del(&w->offset_timer);
  
  	options_free(w->options);
  
  	free(w->name);
  	free(w);
  }
  
  int
  window_pane_destroy_ready(struct window_pane *wp)
  {
  	int	n;
  
  	if (wp->pipe_fd != -1) {
  		if (EVBUFFER_LENGTH(wp->pipe_event->output) != 0)
  			return (0);
  		if (ioctl(wp->fd, FIONREAD, &n) != -1 && n > 0)
  			return (0);
  	}
  
  	if (~wp->flags & PANE_EXITED)
  		return (0);
  	return (1);
  }
  
  void
  window_add_ref(struct window *w, const char *from)
  {
  	w->references++;
  	log_debug("%s: @%u %s, now %d", __func__, w->id, from, w->references);
  }
  
  void
  window_remove_ref(struct window *w, const char *from)
  {
  	w->references--;
  	log_debug("%s: @%u %s, now %d", __func__, w->id, from, w->references);
  
  	if (w->references == 0)
  		window_destroy(w);
  }
  
  void
  window_set_name(struct window *w, const char *new_name)
  {
  	free(w->name);
  	utf8_stravis(&w->name, new_name, VIS_OCTAL|VIS_CSTYLE|VIS_TAB|VIS_NL);
  	notify_window("window-renamed", w);
  }
  
  void
  window_resize(struct window *w, u_int sx, u_int sy)
  {
  	log_debug("%s: @%u resize %ux%u", __func__, w->id, sx, sy);
  	w->sx = sx;
  	w->sy = sy;
  }
  
  int
  window_has_pane(struct window *w, struct window_pane *wp)
  {
  	struct window_pane	*wp1;
  
  	TAILQ_FOREACH(wp1, &w->panes, entry) {
  		if (wp1 == wp)
  			return (1);
  	}
  	return (0);
  }
  
  int
  window_set_active_pane(struct window *w, struct window_pane *wp, int notify)
  {
  	log_debug("%s: pane %%%u", __func__, wp->id);
  
  	if (wp == w->active)
  		return (0);
  	w->last = w->active;
  
  	w->active = wp;
  	w->active->active_point = next_active_point++;
  	w->active->flags |= PANE_CHANGED;
  
  	tty_update_window_offset(w);
  
  	if (notify)
  		notify_window("window-pane-changed", w);
  	return (1);
  }
  
  void
  window_redraw_active_switch(struct window *w, struct window_pane *wp)
  {
  	struct style	*sy1, *sy2;
  	int		 c1, c2;
  
  	if (wp == w->active)
  		return;
  
  	for (;;) {
  		/*
  		 * If the active and inactive styles or palettes are different,
  		 * need to redraw the panes.
  		 */
  		sy1 = &wp->cached_style;
  		sy2 = &wp->cached_active_style;
  		if (!style_equal(sy1, sy2))
  			wp->flags |= PANE_REDRAW;
  		else {
  			c1 = window_pane_get_palette(wp, sy1->gc.fg);
  			c2 = window_pane_get_palette(wp, sy2->gc.fg);
  			if (c1 != c2)
  				wp->flags |= PANE_REDRAW;
  			else {
  				c1 = window_pane_get_palette(wp, sy1->gc.bg);
  				c2 = window_pane_get_palette(wp, sy2->gc.bg);
  				if (c1 != c2)
  					wp->flags |= PANE_REDRAW;
  			}
  		}
  		if (wp == w->active)
  			break;
  		wp = w->active;
  	}
  }
  
  struct window_pane *
  window_get_active_at(struct window *w, u_int x, u_int y)
  {
  	struct window_pane	*wp;
  
  	TAILQ_FOREACH(wp, &w->panes, entry) {
  		if (!window_pane_visible(wp))
  			continue;
  		if (x < wp->xoff || x > wp->xoff + wp->sx)
  			continue;
  		if (y < wp->yoff || y > wp->yoff + wp->sy)
  			continue;
  		return (wp);
  	}
  	return (NULL);
  }
  
  struct window_pane *
  window_find_string(struct window *w, const char *s)
  {
  	u_int	x, y;
  
  	x = w->sx / 2;
  	y = w->sy / 2;
  
  	if (strcasecmp(s, "top") == 0)
  		y = 0;
  	else if (strcasecmp(s, "bottom") == 0)
  		y = w->sy - 1;
  	else if (strcasecmp(s, "left") == 0)
  		x = 0;
  	else if (strcasecmp(s, "right") == 0)
  		x = w->sx - 1;
  	else if (strcasecmp(s, "top-left") == 0) {
  		x = 0;
  		y = 0;
  	} else if (strcasecmp(s, "top-right") == 0) {
  		x = w->sx - 1;
  		y = 0;
  	} else if (strcasecmp(s, "bottom-left") == 0) {
  		x = 0;
  		y = w->sy - 1;
  	} else if (strcasecmp(s, "bottom-right") == 0) {
  		x = w->sx - 1;
  		y = w->sy - 1;
  	} else
  		return (NULL);
  
  	return (window_get_active_at(w, x, y));
  }
  
  int
  window_zoom(struct window_pane *wp)
  {
  	struct window		*w = wp->window;
  	struct window_pane	*wp1;
  
  	if (w->flags & WINDOW_ZOOMED)
  		return (-1);
  
  	if (window_count_panes(w) == 1)
  		return (-1);
  
  	if (w->active != wp)
  		window_set_active_pane(w, wp, 1);
  
  	TAILQ_FOREACH(wp1, &w->panes, entry) {
  		wp1->saved_layout_cell = wp1->layout_cell;
  		wp1->layout_cell = NULL;
  	}
  
  	w->saved_layout_root = w->layout_root;
  	layout_init(w, wp);
  	w->flags |= WINDOW_ZOOMED;
  	notify_window("window-layout-changed", w);
  
  	return (0);
  }
  
  int
  window_unzoom(struct window *w)
  {
  	struct window_pane	*wp;
  
  	if (!(w->flags & WINDOW_ZOOMED))
  		return (-1);
  
  	w->flags &= ~WINDOW_ZOOMED;
  	layout_free(w);
  	w->layout_root = w->saved_layout_root;
  	w->saved_layout_root = NULL;
  
  	TAILQ_FOREACH(wp, &w->panes, entry) {
  		wp->layout_cell = wp->saved_layout_cell;
  		wp->saved_layout_cell = NULL;
  	}
  	layout_fix_panes(w);
  	notify_window("window-layout-changed", w);
  
  	return (0);
  }
  
  int
  window_push_zoom(struct window *w, int flag)
  {
  	log_debug("%s: @%u %d", __func__, w->id,
  	    flag && (w->flags & WINDOW_ZOOMED));
  	if (flag && (w->flags & WINDOW_ZOOMED))
  		w->flags |= WINDOW_WASZOOMED;
  	else
  		w->flags &= ~WINDOW_WASZOOMED;
  	return (window_unzoom(w) == 0);
  }
  
  int
  window_pop_zoom(struct window *w)
  {
  	log_debug("%s: @%u %d", __func__, w->id,
  	    !!(w->flags & WINDOW_WASZOOMED));
  	if (w->flags & WINDOW_WASZOOMED)
  		return (window_zoom(w->active) == 0);
  	return (0);
  }
  
  struct window_pane *
  window_add_pane(struct window *w, struct window_pane *other, u_int hlimit,
      int flags)
  {
  	struct window_pane	*wp;
  
  	if (other == NULL)
  		other = w->active;
  
  	wp = window_pane_create(w, w->sx, w->sy, hlimit);
  	if (TAILQ_EMPTY(&w->panes)) {
  		log_debug("%s: @%u at start", __func__, w->id);
  		TAILQ_INSERT_HEAD(&w->panes, wp, entry);
  	} else if (flags & SPAWN_BEFORE) {
  		log_debug("%s: @%u before %%%u", __func__, w->id, wp->id);
  		if (flags & SPAWN_FULLSIZE)
  			TAILQ_INSERT_HEAD(&w->panes, wp, entry);
  		else
  			TAILQ_INSERT_BEFORE(other, wp, entry);
  	} else {
  		log_debug("%s: @%u after %%%u", __func__, w->id, wp->id);
  		if (flags & SPAWN_FULLSIZE)
  			TAILQ_INSERT_TAIL(&w->panes, wp, entry);
  		else
  			TAILQ_INSERT_AFTER(&w->panes, other, wp, entry);
  	}
  	return (wp);
  }
  
  void
  window_lost_pane(struct window *w, struct window_pane *wp)
  {
  	log_debug("%s: @%u pane %%%u", __func__, w->id, wp->id);
  
  	if (wp == marked_pane.wp)
  		server_clear_marked();
  
  	if (wp == w->active) {
  		w->active = w->last;
  		w->last = NULL;
  		if (w->active == NULL) {
  			w->active = TAILQ_PREV(wp, window_panes, entry);
  			if (w->active == NULL)
  				w->active = TAILQ_NEXT(wp, entry);
  		}
  		if (w->active != NULL) {
  			w->active->flags |= PANE_CHANGED;
  			notify_window("window-pane-changed", w);
  		}
  	} else if (wp == w->last)
  		w->last = NULL;
  }
  
  void
  window_remove_pane(struct window *w, struct window_pane *wp)
  {
  	window_lost_pane(w, wp);
  
  	TAILQ_REMOVE(&w->panes, wp, entry);
  	window_pane_destroy(wp);
  }
  
  struct window_pane *
  window_pane_at_index(struct window *w, u_int idx)
  {
  	struct window_pane	*wp;
  	u_int			 n;
  
  	n = options_get_number(w->options, "pane-base-index");
  	TAILQ_FOREACH(wp, &w->panes, entry) {
  		if (n == idx)
  			return (wp);
  		n++;
  	}
  	return (NULL);
  }
  
  struct window_pane *
  window_pane_next_by_number(struct window *w, struct window_pane *wp, u_int n)
  {
  	for (; n > 0; n--) {
  		if ((wp = TAILQ_NEXT(wp, entry)) == NULL)
  			wp = TAILQ_FIRST(&w->panes);
  	}
  
  	return (wp);
  }
  
  struct window_pane *
  window_pane_previous_by_number(struct window *w, struct window_pane *wp,
      u_int n)
  {
  	for (; n > 0; n--) {
  		if ((wp = TAILQ_PREV(wp, window_panes, entry)) == NULL)
  			wp = TAILQ_LAST(&w->panes, window_panes);
  	}
  
  	return (wp);
  }
  
  int
  window_pane_index(struct window_pane *wp, u_int *i)
  {
  	struct window_pane	*wq;
  	struct window		*w = wp->window;
  
  	*i = options_get_number(w->options, "pane-base-index");
  	TAILQ_FOREACH(wq, &w->panes, entry) {
  		if (wp == wq) {
  			return (0);
  		}
  		(*i)++;
  	}
  
  	return (-1);
  }
  
  u_int
  window_count_panes(struct window *w)
  {
  	struct window_pane	*wp;
  	u_int			 n;
  
  	n = 0;
  	TAILQ_FOREACH(wp, &w->panes, entry)
  		n++;
  	return (n);
  }
  
  void
  window_destroy_panes(struct window *w)
  {
  	struct window_pane	*wp;
  
  	while (!TAILQ_EMPTY(&w->panes)) {
  		wp = TAILQ_FIRST(&w->panes);
  		TAILQ_REMOVE(&w->panes, wp, entry);
  		window_pane_destroy(wp);
  	}
  }
  
  const char *
  window_printable_flags(struct winlink *wl)
  {
  	struct session	*s = wl->session;
  	static char	 flags[32];
  	int		 pos;
  
  	pos = 0;
  	if (wl->flags & WINLINK_ACTIVITY)
  		flags[pos++] = '#';
  	if (wl->flags & WINLINK_BELL)
  		flags[pos++] = '!';
  	if (wl->flags & WINLINK_SILENCE)
  		flags[pos++] = '~';
  	if (wl == s->curw)
  		flags[pos++] = '*';
  	if (wl == TAILQ_FIRST(&s->lastw))
  		flags[pos++] = '-';
  	if (server_check_marked() && wl == marked_pane.wl)
  		flags[pos++] = 'M';
  	if (wl->window->flags & WINDOW_ZOOMED)
  		flags[pos++] = 'Z';
  	flags[pos] = '\0';
  	return (flags);
  }
  
  struct window_pane *
  window_pane_find_by_id_str(const char *s)
  {
  	const char	*errstr;
  	u_int		 id;
  
  	if (*s != '%')
  		return (NULL);
  
  	id = strtonum(s + 1, 0, UINT_MAX, &errstr);
  	if (errstr != NULL)
  		return (NULL);
  	return (window_pane_find_by_id(id));
  }
  
  struct window_pane *
  window_pane_find_by_id(u_int id)
  {
  	struct window_pane	wp;
  
  	wp.id = id;
  	return (RB_FIND(window_pane_tree, &all_window_panes, &wp));
  }
  
  static struct window_pane *
  window_pane_create(struct window *w, u_int sx, u_int sy, u_int hlimit)
  {
  	struct window_pane	*wp;
  	char			 host[HOST_NAME_MAX + 1];
  
  	wp = xcalloc(1, sizeof *wp);
  	wp->window = w;
  	wp->options = options_create(w->options);
  	wp->flags = PANE_STYLECHANGED;
  
  	wp->id = next_window_pane_id++;
  	RB_INSERT(window_pane_tree, &all_window_panes, wp);
  
  	wp->argc = 0;
  	wp->argv = NULL;
  	wp->shell = NULL;
  	wp->cwd = NULL;
  
  	wp->fd = -1;
  	wp->event = NULL;
  
  	TAILQ_INIT(&wp->modes);
  
  	wp->layout_cell = NULL;
  
  	wp->xoff = 0;
  	wp->yoff = 0;
  
  	wp->sx = wp->osx = sx;
  	wp->sy = wp->osx = sy;
  
  	wp->pipe_fd = -1;
  	wp->pipe_off = 0;
  	wp->pipe_event = NULL;
  
  	wp->saved_grid = NULL;
  	wp->saved_cx = UINT_MAX;
  	wp->saved_cy = UINT_MAX;
  
  	screen_init(&wp->base, sx, sy, hlimit);
  	wp->screen = &wp->base;
  
  	screen_init(&wp->status_screen, 1, 1, 0);
  
  	if (gethostname(host, sizeof host) == 0)
  		screen_set_title(&wp->base, host);
  
  	input_init(wp);
  
  	return (wp);
  }
  
  static void
  window_pane_destroy(struct window_pane *wp)
  {
  	window_pane_reset_mode_all(wp);
  	free(wp->searchstr);
  
  	if (wp->fd != -1) {
  #ifdef HAVE_UTEMPTER
  		utempter_remove_record(wp->fd);
  #endif
  		bufferevent_free(wp->event);
  		close(wp->fd);
  	}
  
  	input_free(wp);
  
  	screen_free(&wp->status_screen);
  
  	screen_free(&wp->base);
  	if (wp->saved_grid != NULL)
  		grid_destroy(wp->saved_grid);
  
  	if (wp->pipe_fd != -1) {
  		bufferevent_free(wp->pipe_event);
  		close(wp->pipe_fd);
  	}
  
  	if (event_initialized(&wp->resize_timer))
  		event_del(&wp->resize_timer);
  
  	RB_REMOVE(window_pane_tree, &all_window_panes, wp);
  
  	options_free(wp->options);
  	free((void *)wp->cwd);
  	free(wp->shell);
  	cmd_free_argv(wp->argc, wp->argv);
  	free(wp->palette);
  	free(wp);
  }
  
  static void
  window_pane_read_callback(__unused struct bufferevent *bufev, void *data)
  {
  	struct window_pane	*wp = data;
  	struct evbuffer		*evb = wp->event->input;
  	size_t			 size = EVBUFFER_LENGTH(evb);
  	char			*new_data;
  	size_t			 new_size;
  
  	new_size = size - wp->pipe_off;
  	if (wp->pipe_fd != -1 && new_size > 0) {
  		new_data = EVBUFFER_DATA(evb) + wp->pipe_off;
  		bufferevent_write(wp->pipe_event, new_data, new_size);
  	}
  
  	log_debug("%%%u has %zu bytes", wp->id, size);
  	input_parse(wp);
  
  	wp->pipe_off = EVBUFFER_LENGTH(evb);
  }
  
  static void
  window_pane_error_callback(__unused struct bufferevent *bufev,
      __unused short what, void *data)
  {
  	struct window_pane *wp = data;
  
  	log_debug("%%%u error", wp->id);
  	wp->flags |= PANE_EXITED;
  
  	if (window_pane_destroy_ready(wp))
  		server_destroy_pane(wp, 1);
  }
  
  void
  window_pane_set_event(struct window_pane *wp)
  {
  	setblocking(wp->fd, 0);
  
  	wp->event = bufferevent_new(wp->fd, window_pane_read_callback,
  	    NULL, window_pane_error_callback, wp);
  
  	bufferevent_setwatermark(wp->event, EV_READ, 0, READ_SIZE);
  	bufferevent_enable(wp->event, EV_READ|EV_WRITE);
  }
  
  void
  window_pane_resize(struct window_pane *wp, u_int sx, u_int sy)
  {
  	struct window_mode_entry	*wme;
  
  	if (sx == wp->sx && sy == wp->sy)
  		return;
  	wp->sx = sx;
  	wp->sy = sy;
  
  	log_debug("%s: %%%u resize %ux%u", __func__, wp->id, sx, sy);
  	screen_resize(&wp->base, sx, sy, wp->saved_grid == NULL);
  
  	wme = TAILQ_FIRST(&wp->modes);
  	if (wme != NULL && wme->mode->resize != NULL)
  		wme->mode->resize(wme, sx, sy);
  
  	wp->flags |= (PANE_RESIZE|PANE_RESIZED);
  }
  
  /*
   * Enter alternative screen mode. A copy of the visible screen is saved and the
   * history is not updated
   */
  void
  window_pane_alternate_on(struct window_pane *wp, struct grid_cell *gc,
      int cursor)
  {
  	struct screen	*s = &wp->base;
  	u_int		 sx, sy;
  
  	if (wp->saved_grid != NULL)
  		return;
  	if (!options_get_number(wp->options, "alternate-screen"))
  		return;
  	sx = screen_size_x(s);
  	sy = screen_size_y(s);
  
  	wp->saved_grid = grid_create(sx, sy, 0);
  	grid_duplicate_lines(wp->saved_grid, 0, s->grid, screen_hsize(s), sy);
  	if (cursor) {
  		wp->saved_cx = s->cx;
  		wp->saved_cy = s->cy;
  	}
  	memcpy(&wp->saved_cell, gc, sizeof wp->saved_cell);
  
  	grid_view_clear(s->grid, 0, 0, sx, sy, 8);
  
  	wp->base.grid->flags &= ~GRID_HISTORY;
  
  	wp->flags |= PANE_REDRAW;
  }
  
  /* Exit alternate screen mode and restore the copied grid. */
  void
  window_pane_alternate_off(struct window_pane *wp, struct grid_cell *gc,
      int cursor)
  {
  	struct screen	*s = &wp->base;
  	u_int		 sx, sy;
  
  	if (!options_get_number(wp->options, "alternate-screen"))
  		return;
  
  	/*
  	 * Restore the cursor position and cell. This happens even if not
  	 * currently in the alternate screen.
  	 */
  	if (cursor && wp->saved_cx != UINT_MAX && wp->saved_cy != UINT_MAX) {
  		s->cx = wp->saved_cx;
  		if (s->cx > screen_size_x(s) - 1)
  			s->cx = screen_size_x(s) - 1;
  		s->cy = wp->saved_cy;
  		if (s->cy > screen_size_y(s) - 1)
  			s->cy = screen_size_y(s) - 1;
  		memcpy(gc, &wp->saved_cell, sizeof *gc);
  	}
  
  	if (wp->saved_grid == NULL)
  		return;
  	sx = screen_size_x(s);
  	sy = screen_size_y(s);
  
  	/*
  	 * If the current size is bigger, temporarily resize to the old size
  	 * before copying back.
  	 */
  	if (sy > wp->saved_grid->sy)
  		screen_resize(s, sx, wp->saved_grid->sy, 1);
  
  	/* Restore the saved grid. */
  	grid_duplicate_lines(s->grid, screen_hsize(s), wp->saved_grid, 0, sy);
  
  	/*
  	 * Turn history back on (so resize can use it) and then resize back to
  	 * the current size.
  	 */
  	wp->base.grid->flags |= GRID_HISTORY;
  	if (sy > wp->saved_grid->sy || sx != wp->saved_grid->sx)
  		screen_resize(s, sx, sy, 1);
  
  	grid_destroy(wp->saved_grid);
  	wp->saved_grid = NULL;
  
  	wp->flags |= PANE_REDRAW;
  }
  
  void
  window_pane_set_palette(struct window_pane *wp, u_int n, int colour)
  {
  	if (n > 0xff)
  		return;
  
  	if (wp->palette == NULL)
  		wp->palette = xcalloc(0x100, sizeof *wp->palette);
  
  	wp->palette[n] = colour;
  	wp->flags |= PANE_REDRAW;
  }
  
  void
  window_pane_unset_palette(struct window_pane *wp, u_int n)
  {
  	if (n > 0xff || wp->palette == NULL)
  		return;
  
  	wp->palette[n] = 0;
  	wp->flags |= PANE_REDRAW;
  }
  
  void
  window_pane_reset_palette(struct window_pane *wp)
  {
  	if (wp->palette == NULL)
  		return;
  
  	free(wp->palette);
  	wp->palette = NULL;
  	wp->flags |= PANE_REDRAW;
  }
  
  int
  window_pane_get_palette(struct window_pane *wp, int c)
  {
  	int	new;
  
  	if (wp == NULL || wp->palette == NULL)
  		return (-1);
  
  	new = -1;
  	if (c < 8)
  		new = wp->palette[c];
  	else if (c >= 90 && c <= 97)
  		new = wp->palette[8 + c - 90];
  	else if (c & COLOUR_FLAG_256)
  		new = wp->palette[c & ~COLOUR_FLAG_256];
  	if (new == 0)
  		return (-1);
  	return (new);
  }
  
  static void
  window_pane_mode_timer(__unused int fd, __unused short events, void *arg)
  {
  	struct window_pane	*wp = arg;
  	struct timeval		 tv = { .tv_sec = 10 };
  	int			 n = 0;
  
  	evtimer_del(&wp->modetimer);
  	evtimer_add(&wp->modetimer, &tv);
  
  	log_debug("%%%u in mode: last=%ld", wp->id, (long)wp->modelast);
  
  	if (wp->modelast < time(NULL) - WINDOW_MODE_TIMEOUT) {
  		if (ioctl(wp->fd, FIONREAD, &n) == -1 || n > 0)
  			window_pane_reset_mode_all(wp);
  	}
  }
  
  int
  window_pane_set_mode(struct window_pane *wp, const struct window_mode *mode,
      struct cmd_find_state *fs, struct args *args)
  {
  	struct timeval			 tv = { .tv_sec = 10 };
  	struct window_mode_entry	*wme;
  
  	if (!TAILQ_EMPTY(&wp->modes) && TAILQ_FIRST(&wp->modes)->mode == mode)
  		return (1);
  
  	wp->modelast = time(NULL);
  	if (TAILQ_EMPTY(&wp->modes)) {
  		evtimer_set(&wp->modetimer, window_pane_mode_timer, wp);
  		evtimer_add(&wp->modetimer, &tv);
  	}
  
  	TAILQ_FOREACH(wme, &wp->modes, entry) {
  		if (wme->mode == mode)
  			break;
  	}
  	if (wme != NULL) {
  		TAILQ_REMOVE(&wp->modes, wme, entry);
  		TAILQ_INSERT_HEAD(&wp->modes, wme, entry);
  	} else {
  		wme = xcalloc(1, sizeof *wme);
  		wme->wp = wp;
  		wme->mode = mode;
  		wme->prefix = 1;
  		TAILQ_INSERT_HEAD(&wp->modes, wme, entry);
  		wme->screen = wme->mode->init(wme, fs, args);
  	}
  
  	wp->screen = wme->screen;
  	wp->flags |= (PANE_REDRAW|PANE_CHANGED);
  
  	server_status_window(wp->window);
  	notify_pane("pane-mode-changed", wp);
  
  	return (0);
  }
  
  void
  window_pane_reset_mode(struct window_pane *wp)
  {
  	struct window_mode_entry	*wme, *next;
  
  	if (TAILQ_EMPTY(&wp->modes))
  		return;
  
  	wme = TAILQ_FIRST(&wp->modes);
  	TAILQ_REMOVE(&wp->modes, wme, entry);
  	wme->mode->free(wme);
  	free(wme);
  
  	next = TAILQ_FIRST(&wp->modes);
  	if (next == NULL) {
  		log_debug("%s: no next mode", __func__);
  		evtimer_del(&wp->modetimer);
  		wp->screen = &wp->base;
  	} else {
  		log_debug("%s: next mode is %s", __func__, next->mode->name);
  		wp->screen = next->screen;
  		if (next->mode->resize != NULL)
  			next->mode->resize(next, wp->sx, wp->sy);
  	}
  	wp->flags |= (PANE_REDRAW|PANE_CHANGED);
  
  	server_status_window(wp->window);
  	notify_pane("pane-mode-changed", wp);
  }
  
  void
  window_pane_reset_mode_all(struct window_pane *wp)
  {
  	while (!TAILQ_EMPTY(&wp->modes))
  		window_pane_reset_mode(wp);
  }
  
  void
  window_pane_key(struct window_pane *wp, struct client *c, struct session *s,
      struct winlink *wl, key_code key, struct mouse_event *m)
  {
  	struct window_mode_entry	*wme;
  	struct window_pane		*wp2;
  
  	if (KEYC_IS_MOUSE(key) && m == NULL)
  		return;
  
  	wme = TAILQ_FIRST(&wp->modes);
  	if (wme != NULL) {
  		wp->modelast = time(NULL);
  		if (wme->mode->key != NULL)
  			wme->mode->key(wme, c, s, wl, (key & ~KEYC_XTERM), m);
  		return;
  	}
  
  	if (wp->fd == -1 || wp->flags & PANE_INPUTOFF)
  		return;
  
  	input_key(wp, key, m);
  
  	if (KEYC_IS_MOUSE(key))
  		return;
  	if (options_get_number(wp->window->options, "synchronize-panes")) {
  		TAILQ_FOREACH(wp2, &wp->window->panes, entry) {
  			if (wp2 != wp &&
  			    TAILQ_EMPTY(&wp2->modes) &&
  			    wp2->fd != -1 &&
  			    (~wp2->flags & PANE_INPUTOFF) &&
  			    window_pane_visible(wp2))
  				input_key(wp2, key, NULL);
  		}
  	}
  }
  
  int
  window_pane_visible(struct window_pane *wp)
  {
  	if (~wp->window->flags & WINDOW_ZOOMED)
  		return (1);
  	return (wp == wp->window->active);
  }
  
  u_int
  window_pane_search(struct window_pane *wp, const char *term, int regex,
      int ignore)
  {
  	struct screen	*s = &wp->base;
  	regex_t		 r;
  	char		*new = NULL, *line;
  	u_int		 i;
  	int		 flags = 0, found;
  	size_t		 n;
  
  	if (!regex) {
  		if (ignore)
  			flags |= FNM_CASEFOLD;
  		xasprintf(&new, "*%s*", term);
  	} else {
  		if (ignore)
  			flags |= REG_ICASE;
  		if (regcomp(&r, term, flags|REG_EXTENDED) != 0)
  			return (0);
  	}
  
  	for (i = 0; i < screen_size_y(s); i++) {
  		line = grid_view_string_cells(s->grid, 0, i, screen_size_x(s));
  		for (n = strlen(line); n > 0; n--) {
  			if (!isspace((u_char)line[n - 1]))
  				break;
  			line[n - 1] = '\0';
  		}
  		log_debug("%s: %s", __func__, line);
  		if (!regex)
  			found = (fnmatch(new, line, 0) == 0);
  		else
  			found = (regexec(&r, line, 0, NULL, 0) == 0);
  		free(line);
  		if (found)
  			break;
  	}
  	if (!regex)
  		free(new);
  	else
  		regfree(&r);
  
  	if (i == screen_size_y(s))
  		return (0);
  	return (i + 1);
  }
  
  /* Get MRU pane from a list. */
  static struct window_pane *
  window_pane_choose_best(struct window_pane **list, u_int size)
  {
  	struct window_pane	*next, *best;
  	u_int			 i;
  
  	if (size == 0)
  		return (NULL);
  
  	best = list[0];
  	for (i = 1; i < size; i++) {
  		next = list[i];
  		if (next->active_point > best->active_point)
  			best = next;
  	}
  	return (best);
  }
  
  /*
   * Find the pane directly above another. We build a list of those adjacent to
   * top edge and then choose the best.
   */
  struct window_pane *
  window_pane_find_up(struct window_pane *wp)
  {
  	struct window		*w;
  	struct window_pane	*next, *best, **list;
  	u_int			 edge, left, right, end, size;
  	int			 status, found;
  
  	if (wp == NULL)
  		return (NULL);
  	w = wp->window;
  	status = options_get_number(w->options, "pane-border-status");
  
  	list = NULL;
  	size = 0;
  
  	edge = wp->yoff;
  	if (status == PANE_STATUS_TOP) {
  		if (edge == 1)
  			edge = w->sy + 1;
  	} else if (status == PANE_STATUS_BOTTOM) {
  		if (edge == 0)
  			edge = w->sy;
  	} else {
  		if (edge == 0)
  			edge = w->sy + 1;
  	}
  
  	left = wp->xoff;
  	right = wp->xoff + wp->sx;
  
  	TAILQ_FOREACH(next, &w->panes, entry) {
  		if (next == wp)
  			continue;
  		if (next->yoff + next->sy + 1 != edge)
  			continue;
  		end = next->xoff + next->sx - 1;
  
  		found = 0;
  		if (next->xoff < left && end > right)
  			found = 1;
  		else if (next->xoff >= left && next->xoff <= right)
  			found = 1;
  		else if (end >= left && end <= right)
  			found = 1;
  		if (!found)
  			continue;
  		list = xreallocarray(list, size + 1, sizeof *list);
  		list[size++] = next;
  	}
  
  	best = window_pane_choose_best(list, size);
  	free(list);
  	return (best);
  }
  
  /* Find the pane directly below another. */
  struct window_pane *
  window_pane_find_down(struct window_pane *wp)
  {
  	struct window		*w;
  	struct window_pane	*next, *best, **list;
  	u_int			 edge, left, right, end, size;
  	int			 status, found;
  
  	if (wp == NULL)
  		return (NULL);
  	w = wp->window;
  	status = options_get_number(w->options, "pane-border-status");
  
  	list = NULL;
  	size = 0;
  
  	edge = wp->yoff + wp->sy + 1;
  	if (status == PANE_STATUS_TOP) {
  		if (edge >= w->sy)
  			edge = 1;
  	} else if (status == PANE_STATUS_BOTTOM) {
  		if (edge >= w->sy - 1)
  			edge = 0;
  	} else {
  		if (edge >= w->sy)
  			edge = 0;
  	}
  
  	left = wp->xoff;
  	right = wp->xoff + wp->sx;
  
  	TAILQ_FOREACH(next, &w->panes, entry) {
  		if (next == wp)
  			continue;
  		if (next->yoff != edge)
  			continue;
  		end = next->xoff + next->sx - 1;
  
  		found = 0;
  		if (next->xoff < left && end > right)
  			found = 1;
  		else if (next->xoff >= left && next->xoff <= right)
  			found = 1;
  		else if (end >= left && end <= right)
  			found = 1;
  		if (!found)
  			continue;
  		list = xreallocarray(list, size + 1, sizeof *list);
  		list[size++] = next;
  	}
  
  	best = window_pane_choose_best(list, size);
  	free(list);
  	return (best);
  }
  
  /* Find the pane directly to the left of another. */
  struct window_pane *
  window_pane_find_left(struct window_pane *wp)
  {
  	struct window		*w;
  	struct window_pane	*next, *best, **list;
  	u_int			 edge, top, bottom, end, size;
  	int			 found;
  
  	if (wp == NULL)
  		return (NULL);
  	w = wp->window;
  
  	list = NULL;
  	size = 0;
  
  	edge = wp->xoff;
  	if (edge == 0)
  		edge = w->sx + 1;
  
  	top = wp->yoff;
  	bottom = wp->yoff + wp->sy;
  
  	TAILQ_FOREACH(next, &w->panes, entry) {
  		if (next == wp)
  			continue;
  		if (next->xoff + next->sx + 1 != edge)
  			continue;
  		end = next->yoff + next->sy - 1;
  
  		found = 0;
  		if (next->yoff < top && end > bottom)
  			found = 1;
  		else if (next->yoff >= top && next->yoff <= bottom)
  			found = 1;
  		else if (end >= top && end <= bottom)
  			found = 1;
  		if (!found)
  			continue;
  		list = xreallocarray(list, size + 1, sizeof *list);
  		list[size++] = next;
  	}
  
  	best = window_pane_choose_best(list, size);
  	free(list);
  	return (best);
  }
  
  /* Find the pane directly to the right of another. */
  struct window_pane *
  window_pane_find_right(struct window_pane *wp)
  {
  	struct window		*w;
  	struct window_pane	*next, *best, **list;
  	u_int			 edge, top, bottom, end, size;
  	int			 found;
  
  	if (wp == NULL)
  		return (NULL);
  	w = wp->window;
  
  	list = NULL;
  	size = 0;
  
  	edge = wp->xoff + wp->sx + 1;
  	if (edge >= w->sx)
  		edge = 0;
  
  	top = wp->yoff;
  	bottom = wp->yoff + wp->sy;
  
  	TAILQ_FOREACH(next, &w->panes, entry) {
  		if (next == wp)
  			continue;
  		if (next->xoff != edge)
  			continue;
  		end = next->yoff + next->sy - 1;
  
  		found = 0;
  		if (next->yoff < top && end > bottom)
  			found = 1;
  		else if (next->yoff >= top && next->yoff <= bottom)
  			found = 1;
  		else if (end >= top && end <= bottom)
  			found = 1;
  		if (!found)
  			continue;
  		list = xreallocarray(list, size + 1, sizeof *list);
  		list[size++] = next;
  	}
  
  	best = window_pane_choose_best(list, size);
  	free(list);
  	return (best);
  }
  
  /* Clear alert flags for a winlink */
  void
  winlink_clear_flags(struct winlink *wl)
  {
  	struct winlink	*loop;
  
  	wl->window->flags &= ~WINDOW_ALERTFLAGS;
  	TAILQ_FOREACH(loop, &wl->window->winlinks, wentry) {
  		if ((loop->flags & WINLINK_ALERTFLAGS) != 0) {
  			loop->flags &= ~WINLINK_ALERTFLAGS;
  			server_status_session(loop->session);
  		}
  	}
  }
  
  /* Shuffle window indexes up. */
  int
  winlink_shuffle_up(struct session *s, struct winlink *wl)
  {
  	int	 idx, last;
  
  	if (wl == NULL)
  		return (-1);
  	idx = wl->idx + 1;
  
  	/* Find the next free index. */
  	for (last = idx; last < INT_MAX; last++) {
  		if (winlink_find_by_index(&s->windows, last) == NULL)
  			break;
  	}
  	if (last == INT_MAX)
  		return (-1);
  
  	/* Move everything from last - 1 to idx up a bit. */
  	for (; last > idx; last--) {
  		wl = winlink_find_by_index(&s->windows, last - 1);
  		server_link_window(s, wl, s, last, 0, 0, NULL);
  		server_unlink_window(s, wl);
  	}
  
  	return (idx);
  }
  
  static void
  window_pane_input_callback(struct client *c, int closed, void *data)
  {
  	struct window_pane_input_data	*cdata = data;
  	struct window_pane		*wp;
  	struct evbuffer			*evb = c->stdin_data;
  	u_char				*buf = EVBUFFER_DATA(evb);
  	size_t				 len = EVBUFFER_LENGTH(evb);
  
  	wp = window_pane_find_by_id(cdata->wp);
  	if (wp == NULL || closed || c->flags & CLIENT_DEAD) {
  		if (wp == NULL)
  			c->flags |= CLIENT_EXIT;
  		evbuffer_drain(evb, len);
  
  		c->stdin_callback = NULL;
  		server_client_unref(c);
  
  		cmdq_continue(cdata->item);
  		free(cdata);
  
  		return;
  	}
  
  	input_parse_buffer(wp, buf, len);
  	evbuffer_drain(evb, len);
  }
  
  int
  window_pane_start_input(struct window_pane *wp, struct cmdq_item *item,
      char **cause)
  {
  	struct client			*c = item->client;
  	struct window_pane_input_data	*cdata;
  
  	if (~wp->flags & PANE_EMPTY) {
  		*cause = xstrdup("pane is not empty");
  		return (-1);
  	}
  
  	cdata = xmalloc(sizeof *cdata);
  	cdata->item = item;
  	cdata->wp = wp->id;
  
  	return (server_set_stdin_callback(c, window_pane_input_callback, cdata,
  	    cause));
  }
  