text: /* $Id$ */
  
  /*
   * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
   *
   * 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/time.h>
  
  #include <string.h>
  #include <stdlib.h>
  #include <unistd.h>
  #include <time.h>
  
  #include "tmux.h"
  
  /* Global session list. */
  struct sessions	sessions;
  struct sessions dead_sessions;
  u_int		next_session_id;
  struct session_groups session_groups;
  
  struct winlink *session_next_alert(struct winlink *);
  struct winlink *session_previous_alert(struct winlink *);
  
  RB_GENERATE(sessions, session, entry, session_cmp);
  
  int
  session_cmp(struct session *s1, struct session *s2)
  {
  	return (strcmp(s1->name, s2->name));
  }
  
  /*
   * Find if session is still alive. This is true if it is still on the global
   * sessions list.
   */
  int
  session_alive(struct session *s)
  {
  	struct session *s_loop;
  
  	RB_FOREACH(s_loop, sessions, &sessions) {
  		if (s_loop == s)
  			return (1);
  	}
  	return (0);
  }
  
  /* Find session by name. */
  struct session *
  session_find(const char *name)
  {
  	struct session	s;
  
  	s.name = (char *) name;
  	return (RB_FIND(sessions, &sessions, &s));
  }
  
  /* Find session by id. */
  struct session *
  session_find_by_id(u_int id)
  {
  	struct session	*s;
  
  	RB_FOREACH(s, sessions, &sessions) {
  		if (s->id == id)
  			return (s);
  	}
  	return (NULL);
  }
  
  /* Create a new session. */
  struct session *
  session_create(const char *name, const char *cmd, int cwd, struct environ *env,
      struct termios *tio, int idx, u_int sx, u_int sy, char **cause)
  {
  	struct session	*s;
  
  	s = xmalloc(sizeof *s);
  	s->references = 0;
  	s->flags = 0;
  
  	if (gettimeofday(&s->creation_time, NULL) != 0)
  		fatal("gettimeofday failed");
  	session_update_activity(s);
  
  	s->cwd = dup(cwd);
  
  	s->curw = NULL;
  	TAILQ_INIT(&s->lastw);
  	RB_INIT(&s->windows);
  
  	options_init(&s->options, &global_s_options);
  	environ_init(&s->environ);
  	if (env != NULL)
  		environ_copy(env, &s->environ);
  
  	s->tio = NULL;
  	if (tio != NULL) {
  		s->tio = xmalloc(sizeof *s->tio);
  		memcpy(s->tio, tio, sizeof *s->tio);
  	}
  
  	s->sx = sx;
  	s->sy = sy;
  
  	if (name != NULL) {
  		s->name = xstrdup(name);
  		s->id = next_session_id++;
  	} else {
  		s->name = NULL;
  		do {
  			s->id = next_session_id++;
  			free (s->name);
  			xasprintf(&s->name, "%u", s->id);
  		} while (RB_FIND(sessions, &sessions, s) != NULL);
  	}
  	RB_INSERT(sessions, &sessions, s);
  
  	if (cmd != NULL) {
  		if (session_new(s, NULL, cmd, cwd, idx, cause) == NULL) {
  			session_destroy(s);
  			return (NULL);
  		}
  		session_select(s, RB_ROOT(&s->windows)->idx);
  	}
  
  	log_debug("session %s created", s->name);
  	notify_session_created(s);
  
  	return (s);
  }
  
  /* Destroy a session. */
  void
  session_destroy(struct session *s)
  {
  	struct winlink	*wl;
  
  	log_debug("session %s destroyed", s->name);
  
  	RB_REMOVE(sessions, &sessions, s);
  	notify_session_closed(s);
  
  	free(s->tio);
  
  	session_group_remove(s);
  	environ_free(&s->environ);
  	options_free(&s->options);
  
  	while (!TAILQ_EMPTY(&s->lastw))
  		winlink_stack_remove(&s->lastw, TAILQ_FIRST(&s->lastw));
  	while (!RB_EMPTY(&s->windows)) {
  		wl = RB_ROOT(&s->windows);
  		notify_window_unlinked(s, wl->window);
  		winlink_remove(&s->windows, wl);
  	}
  
  	close(s->cwd);
  
  	RB_INSERT(sessions, &dead_sessions, s);
  }
  
  /* Check a session name is valid: not empty and no colons. */
  int
  session_check_name(const char *name)
  {
  	return (*name != '\0' && strchr(name, ':') == NULL);
  }
  
  /* Update session active time. */
  void
  session_update_activity(struct session *s)
  {
  	if (gettimeofday(&s->activity_time, NULL) != 0)
  		fatal("gettimeofday");
  }
  
  /* Find the next usable session. */
  struct session *
  session_next_session(struct session *s)
  {
  	struct session *s2;
  
  	if (RB_EMPTY(&sessions) || !session_alive(s))
  		return (NULL);
  
  	s2 = RB_NEXT(sessions, &sessions, s);
  	if (s2 == NULL)
  		s2 = RB_MIN(sessions, &sessions);
  	if (s2 == s)
  		return (NULL);
  	return (s2);
  }
  
  /* Find the previous usable session. */
  struct session *
  session_previous_session(struct session *s)
  {
  	struct session *s2;
  
  	if (RB_EMPTY(&sessions) || !session_alive(s))
  		return (NULL);
  
  	s2 = RB_PREV(sessions, &sessions, s);
  	if (s2 == NULL)
  		s2 = RB_MAX(sessions, &sessions);
  	if (s2 == s)
  		return (NULL);
  	return (s2);
  }
  
  /* Create a new window on a session. */
  struct winlink *
  session_new(struct session *s, const char *name, const char *cmd, int cwd,
      int idx, char **cause)
  {
  	struct window	*w;
  	struct winlink	*wl;
  	struct environ	 env;
  	const char	*shell;
  	u_int		 hlimit;
  
  	if ((wl = winlink_add(&s->windows, idx)) == NULL) {
  		xasprintf(cause, "index in use: %d", idx);
  		return (NULL);
  	}
  
  	environ_init(&env);
  	environ_copy(&global_environ, &env);
  	environ_copy(&s->environ, &env);
  	server_fill_environ(s, &env);
  
  	shell = options_get_string(&s->options, "default-shell");
  	if (*shell == '\0' || areshell(shell))
  		shell = _PATH_BSHELL;
  
  	hlimit = options_get_number(&s->options, "history-limit");
  	w = window_create(name, cmd, shell, cwd, &env, s->tio, s->sx, s->sy,
  	    hlimit, cause);
  	if (w == NULL) {
  		winlink_remove(&s->windows, wl);
  		environ_free(&env);
  		return (NULL);
  	}
  	winlink_set_window(wl, w);
  	notify_window_linked(s, w);
  	environ_free(&env);
  
  	if (options_get_number(&s->options, "set-remain-on-exit"))
  		options_set_number(&w->options, "remain-on-exit", 1);
  
  	session_group_synchronize_from(s);
  	return (wl);
  }
  
  /* Attach a window to a session. */
  struct winlink *
  session_attach(struct session *s, struct window *w, int idx, char **cause)
  {
  	struct winlink	*wl;
  
  	if ((wl = winlink_add(&s->windows, idx)) == NULL) {
  		xasprintf(cause, "index in use: %d", idx);
  		return (NULL);
  	}
  	winlink_set_window(wl, w);
  	notify_window_linked(s, w);
  
  	session_group_synchronize_from(s);
  	return (wl);
  }
  
  /* Detach a window from a session. */
  int
  session_detach(struct session *s, struct winlink *wl)
  {
  	if (s->curw == wl &&
  	    session_last(s) != 0 && session_previous(s, 0) != 0)
  		session_next(s, 0);
  
  	wl->flags &= ~WINLINK_ALERTFLAGS;
  	notify_window_unlinked(s, wl->window);
  	winlink_stack_remove(&s->lastw, wl);
  	winlink_remove(&s->windows, wl);
  	session_group_synchronize_from(s);
  	if (RB_EMPTY(&s->windows)) {
  		session_destroy(s);
  		return (1);
  	}
  	return (0);
  }
  
  /* Return if session has window. */
  struct winlink *
  session_has(struct session *s, struct window *w)
  {
  	struct winlink	*wl;
  
  	RB_FOREACH(wl, winlinks, &s->windows) {
  		if (wl->window == w)
  			return (wl);
  	}
  	return (NULL);
  }
  
  struct winlink *
  session_next_alert(struct winlink *wl)
  {
  	while (wl != NULL) {
  		if (wl->flags & WINLINK_ALERTFLAGS)
  			break;
  		wl = winlink_next(wl);
  	}
  	return (wl);
  }
  
  /* Move session to next window. */
  int
  session_next(struct session *s, int alert)
  {
  	struct winlink	*wl;
  
  	if (s->curw == NULL)
  		return (-1);
  
  	wl = winlink_next(s->curw);
  	if (alert)
  		wl = session_next_alert(wl);
  	if (wl == NULL) {
  		wl = RB_MIN(winlinks, &s->windows);
  		if (alert && ((wl = session_next_alert(wl)) == NULL))
  			return (-1);
  	}
  	return (session_set_current(s, wl));
  }
  
  struct winlink *
  session_previous_alert(struct winlink *wl)
  {
  	while (wl != NULL) {
  		if (wl->flags & WINLINK_ALERTFLAGS)
  			break;
  		wl = winlink_previous(wl);
  	}
  	return (wl);
  }
  
  /* Move session to previous window. */
  int
  session_previous(struct session *s, int alert)
  {
  	struct winlink	*wl;
  
  	if (s->curw == NULL)
  		return (-1);
  
  	wl = winlink_previous(s->curw);
  	if (alert)
  		wl = session_previous_alert(wl);
  	if (wl == NULL) {
  		wl = RB_MAX(winlinks, &s->windows);
  		if (alert && (wl = session_previous_alert(wl)) == NULL)
  			return (-1);
  	}
  	return (session_set_current(s, wl));
  }
  
  /* Move session to specific window. */
  int
  session_select(struct session *s, int idx)
  {
  	struct winlink	*wl;
  
  	wl = winlink_find_by_index(&s->windows, idx);
  	return (session_set_current(s, wl));
  }
  
  /* Move session to last used window. */
  int
  session_last(struct session *s)
  {
  	struct winlink	*wl;
  
  	wl = TAILQ_FIRST(&s->lastw);
  	if (wl == NULL)
  		return (-1);
  	if (wl == s->curw)
  		return (1);
  
  	return (session_set_current(s, wl));
  }
  
  /* Set current winlink to wl .*/
  int
  session_set_current(struct session *s, struct winlink *wl)
  {
  	if (wl == NULL)
  		return (-1);
  	if (wl == s->curw)
  		return (1);
  
  	winlink_stack_remove(&s->lastw, wl);
  	winlink_stack_push(&s->lastw, s->curw);
  	s->curw = wl;
  	winlink_clear_flags(wl);
  	return (0);
  }
  
  /* Find the session group containing a session. */
  struct session_group *
  session_group_find(struct session *target)
  {
  	struct session_group	*sg;
  	struct session		*s;
  
  	TAILQ_FOREACH(sg, &session_groups, entry) {
  		TAILQ_FOREACH(s, &sg->sessions, gentry) {
  			if (s == target)
  				return (sg);
  		}
  	}
  	return (NULL);
  }
  
  /* Find session group index. */
  u_int
  session_group_index(struct session_group *sg)
  {
  	struct session_group   *sg2;
  	u_int			i;
  
  	i = 0;
  	TAILQ_FOREACH(sg2, &session_groups, entry) {
  		if (sg == sg2)
  			return (i);
  		i++;
  	}
  
  	fatalx("session group not found");
  }
  
  /*
   * Add a session to the session group containing target, creating it if
   * necessary.
   */
  void
  session_group_add(struct session *target, struct session *s)
  {
  	struct session_group	*sg;
  
  	if ((sg = session_group_find(target)) == NULL) {
  		sg = xmalloc(sizeof *sg);
  		TAILQ_INSERT_TAIL(&session_groups, sg, entry);
  		TAILQ_INIT(&sg->sessions);
  		TAILQ_INSERT_TAIL(&sg->sessions, target, gentry);
  	}
  	TAILQ_INSERT_TAIL(&sg->sessions, s, gentry);
  }
  
  /* Remove a session from its group and destroy the group if empty. */
  void
  session_group_remove(struct session *s)
  {
  	struct session_group	*sg;
  
  	if ((sg = session_group_find(s)) == NULL)
  		return;
  	TAILQ_REMOVE(&sg->sessions, s, gentry);
  	if (TAILQ_NEXT(TAILQ_FIRST(&sg->sessions), gentry) == NULL)
  		TAILQ_REMOVE(&sg->sessions, TAILQ_FIRST(&sg->sessions), gentry);
  	if (TAILQ_EMPTY(&sg->sessions)) {
  		TAILQ_REMOVE(&session_groups, sg, entry);
  		free(sg);
  	}
  }
  
  /* Synchronize a session to its session group. */
  void
  session_group_synchronize_to(struct session *s)
  {
  	struct session_group	*sg;
  	struct session		*target;
  
  	if ((sg = session_group_find(s)) == NULL)
  		return;
  
  	target = NULL;
  	TAILQ_FOREACH(target, &sg->sessions, gentry) {
  		if (target != s)
  			break;
  	}
  	session_group_synchronize1(target, s);
  }
  
  /* Synchronize a session group to a session. */
  void
  session_group_synchronize_from(struct session *target)
  {
  	struct session_group	*sg;
  	struct session		*s;
  
  	if ((sg = session_group_find(target)) == NULL)
  		return;
  
  	TAILQ_FOREACH(s, &sg->sessions, gentry) {
  		if (s != target)
  			session_group_synchronize1(target, s);
  	}
  }
  
  /*
   * Synchronize a session with a target session. This means destroying all
   * winlinks then recreating them, then updating the current window, last window
   * stack and alerts.
   */
  void
  session_group_synchronize1(struct session *target, struct session *s)
  {
  	struct winlinks		 old_windows, *ww;
  	struct winlink_stack	 old_lastw;
  	struct winlink		*wl, *wl2;
  
  	/* Don't do anything if the session is empty (it'll be destroyed). */
  	ww = &target->windows;
  	if (RB_EMPTY(ww))
  		return;
  
  	/* If the current window has vanished, move to the next now. */
  	if (s->curw != NULL &&
  	    winlink_find_by_index(ww, s->curw->idx) == NULL &&
  	    session_last(s) != 0 && session_previous(s, 0) != 0)
  		session_next(s, 0);
  
  	/* Save the old pointer and reset it. */
  	memcpy(&old_windows, &s->windows, sizeof old_windows);
  	RB_INIT(&s->windows);
  
  	/* Link all the windows from the target. */
  	RB_FOREACH(wl, winlinks, ww) {
  		wl2 = winlink_add(&s->windows, wl->idx);
  		winlink_set_window(wl2, wl->window);
  		notify_window_linked(s, wl2->window);
  		wl2->flags |= wl->flags & WINLINK_ALERTFLAGS;
  	}
  
  	/* Fix up the current window. */
  	if (s->curw != NULL)
  		s->curw = winlink_find_by_index(&s->windows, s->curw->idx);
  	else
  		s->curw = winlink_find_by_index(&s->windows, target->curw->idx);
  
  	/* Fix up the last window stack. */
  	memcpy(&old_lastw, &s->lastw, sizeof old_lastw);
  	TAILQ_INIT(&s->lastw);
  	TAILQ_FOREACH(wl, &old_lastw, sentry) {
  		wl2 = winlink_find_by_index(&s->windows, wl->idx);
  		if (wl2 != NULL)
  			TAILQ_INSERT_TAIL(&s->lastw, wl2, sentry);
  	}
  
  	/* Then free the old winlinks list. */
  	while (!RB_EMPTY(&old_windows)) {
  		wl = RB_ROOT(&old_windows);
  		if (winlink_find_by_window_id(&s->windows, wl->window->id) == NULL)
  		    notify_window_unlinked(s, wl->window);
  		winlink_remove(&old_windows, wl);
  	}
  }
  
  /* Renumber the windows across winlinks attached to a specific session. */
  void
  session_renumber_windows(struct session *s)
  {
  	struct winlink		*wl, *wl1, *wl_new;
  	struct winlinks		 old_wins;
  	struct winlink_stack	 old_lastw;
  	int			 new_idx, new_curw_idx;
  
  	/* Save and replace old window list. */
  	memcpy(&old_wins, &s->windows, sizeof old_wins);
  	RB_INIT(&s->windows);
  
  	/* Start renumbering from the base-index if it's set. */
  	new_idx = options_get_number(&s->options, "base-index");
  	new_curw_idx = 0;
  
  	/* Go through the winlinks and assign new indexes. */
  	RB_FOREACH(wl, winlinks, &old_wins) {
  		wl_new = winlink_add(&s->windows, new_idx);
  		winlink_set_window(wl_new, wl->window);
  		wl_new->flags |= wl->flags & WINLINK_ALERTFLAGS;
  
  		if (wl == s->curw)
  			new_curw_idx = wl_new->idx;
  
  		new_idx++;
  	}
  
  	/* Fix the stack of last windows now. */
  	memcpy(&old_lastw, &s->lastw, sizeof old_lastw);
  	TAILQ_INIT(&s->lastw);
  	TAILQ_FOREACH(wl, &old_lastw, sentry) {
  		wl_new = winlink_find_by_window(&s->windows, wl->window);
  		if (wl_new != NULL)
  			TAILQ_INSERT_TAIL(&s->lastw, wl_new, sentry);
  	}
  
  	/* Set the current window. */
  	s->curw = winlink_find_by_index(&s->windows, new_curw_idx);
  
  	/* Free the old winlinks (reducing window references too). */
  	RB_FOREACH_SAFE(wl, winlinks, &old_wins, wl1)
  		winlink_remove(&old_wins, wl);
  }
  