Sync OpenBSD patchset 806:

Store sessions in an RB tree by name rather than a list, this is tidier
and allows them to easily be shown sorted in various lists
(list-sessions/choose-sessions).

Keep a session index which is used in a couple of places internally but
make it an ever-increasing number rather than filling in gaps with new
sessions.

1 files changed, 49 insertions, 64 deletions

diff --git a/session.c b/session.c
index 2badf8bc..25f0ef53 100644
--- a/session.c
+++ b/session.c
@@ -1,4 +1,4 @@
-/* $Id: session.c,v 1.82 2010-12-22 15:33:14 tcunha Exp $ */
+/* $Id: session.c,v 1.83 2010-12-22 15:36:44 tcunha Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -29,11 +29,20 @@
 /* Global session list. */
 struct sessions	sessions;
 struct sessions dead_sessions;
+u_int		next_session;
 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.
@@ -41,24 +50,35 @@ struct winlink *session_previous_alert(struct winlink *);
 int
 session_alive(struct session *s)
 {
-	u_int	idx;
+	struct session *s_loop;
 
-	return (session_index(s, &idx) == 0);
+	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 index. */
+struct session *
+session_find_by_index(u_int idx)
+{
 	struct session	*s;
-	u_int		 i;
 
-	for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
-		s = ARRAY_ITEM(&sessions, i);
-		if (s != NULL && strcmp(s->name, name) == 0)
+	RB_FOREACH(s, sessions, &sessions) {
+		if (s->idx == idx)
 			return (s);
 	}
-
 	return (NULL);
 }
 
@@ -69,7 +89,6 @@ session_create(const char *name, const char *cmd, const char *cwd,
     char **cause)
 {
 	struct session	*s;
-	u_int		 i;
 
 	s = xmalloc(sizeof *s);
 	s->references = 0;
@@ -101,19 +120,12 @@ session_create(const char *name, const char *cmd, const char *cwd,
 	s->sx = sx;
 	s->sy = sy;
 
-	for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
-		if (ARRAY_ITEM(&sessions, i) == NULL) {
-			ARRAY_SET(&sessions, i, s);
-			break;
-		}
-	}
-	if (i == ARRAY_LENGTH(&sessions))
-		ARRAY_ADD(&sessions, s);
-
+	s->idx = next_session++;
 	if (name != NULL)
 		s->name = xstrdup(name);
 	else
-		xasprintf(&s->name, "%u", i);
+		xasprintf(&s->name, "%u", s->idx);
+	RB_INSERT(sessions, &sessions, s);
 
 	if (cmd != NULL) {
 		if (session_new(s, NULL, cmd, cwd, idx, cause) == NULL) {
@@ -132,15 +144,9 @@ session_create(const char *name, const char *cmd, const char *cwd,
 void
 session_destroy(struct session *s)
 {
-	u_int	i;
-
 	log_debug("session %s destroyed", s->name);
 
-	if (session_index(s, &i) != 0)
-		fatalx("session not found");
-	ARRAY_SET(&sessions, i, NULL);
-	while (!ARRAY_EMPTY(&sessions) && ARRAY_LAST(&sessions) == NULL)
-		ARRAY_TRUNC(&sessions, 1);
+	RB_REMOVE(sessions, &sessions, s);
 
 	if (s->tio != NULL)
 		xfree(s->tio);
@@ -156,27 +162,8 @@ session_destroy(struct session *s)
 		winlink_remove(&s->windows, RB_ROOT(&s->windows));
 
 	xfree(s->cwd);
-	xfree(s->name);
 
-	for (i = 0; i < ARRAY_LENGTH(&dead_sessions); i++) {
-		if (ARRAY_ITEM(&dead_sessions, i) == NULL) {
-			ARRAY_SET(&dead_sessions, i, s);
-			break;
-		}
-	}
-	if (i == ARRAY_LENGTH(&dead_sessions))
-		ARRAY_ADD(&dead_sessions, s);
-}
-
-/* Find session index. */
-int
-session_index(struct session *s, u_int *i)
-{
-	for (*i = 0; *i < ARRAY_LENGTH(&sessions); (*i)++) {
-		if (s == ARRAY_ITEM(&sessions, *i))
-			return (0);
-	}
-	return (-1);
+	RB_INSERT(sessions, &dead_sessions, s);
 }
 
 /* Find the next usable session. */
@@ -184,19 +171,18 @@ struct session *
 session_next_session(struct session *s)
 {
 	struct session *s2;
-	u_int		i;
 
-	if (ARRAY_LENGTH(&sessions) == 0 || session_index(s, &i) != 0)
+	if (RB_EMPTY(&sessions) || !session_alive(s))
 		return (NULL);
 
+	s2 = s;
 	do {
-		if (i == ARRAY_LENGTH(&sessions) - 1)
-			i = 0;
-		else
-			i++;
-		s2 = ARRAY_ITEM(&sessions, i);
-	} while (s2 == NULL);
-
+		s2 = RB_NEXT(sessions, &sessions, s2);
+		if (s2 == NULL)
+			s2 = RB_MIN(sessions, &sessions);
+	} while (s2 != s);
+	if (s2 == s)
+		return (NULL);
 	return (s2);
 }
 
@@ -205,19 +191,18 @@ struct session *
 session_previous_session(struct session *s)
 {
 	struct session *s2;
-	u_int		i;
 
-	if (ARRAY_LENGTH(&sessions) == 0 || session_index(s, &i) != 0)
+	if (RB_EMPTY(&sessions) || !session_alive(s))
 		return (NULL);
 
+	s2 = s;
 	do {
-		if (i == 0)
-			i = ARRAY_LENGTH(&sessions) - 1;
-		else
-			i--;
-		s2 = ARRAY_ITEM(&sessions, i);
-	} while (s2 == NULL);
-
+		s2 = RB_PREV(sessions, &sessions, s2);
+		if (s2 == NULL)
+			s2 = RB_MAX(sessions, &sessions);
+	} while (s2 != s);
+	if (s2 == s)
+		return (NULL);
 	return (s2);
 }