From 0926f39da25a742f5d6cfaececb4cc4d53535e8a Mon Sep 17 00:00:00 2001
From: sezero <sezero@af15c1b1-3010-417e-b628-4374ebc0bcbd>
Date: Fri, 31 Dec 2010 07:55:43 +0000
Subject: [PATCH] applied a better fix for the infamous "SV_TouchLinks: next !=
 l->next" problem. Fixes "whiteroom"
 (http://www.quaddicted.com/reviews/whiteroom.html) completely locking the
 engine. fix from the quakeforge sources.

git-svn-id: http://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@359 af15c1b1-3010-417e-b628-4374ebc0bcbd
---
 Quake/world.c | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/Quake/world.c b/Quake/world.c
index 3b369fa3..c6db6b5a 100644
--- a/Quake/world.c
+++ b/Quake/world.c
@@ -262,11 +262,18 @@ SV_UnlinkEdict
 
 ===============
 */
+static link_t	**sv_link_next;
+static link_t	**sv_link_prev;
+
 void SV_UnlinkEdict (edict_t *ent)
 {
 	if (!ent->area.prev)
 		return;		// not linked in anywhere
 	RemoveLink (&ent->area);
+	if (sv_link_next && *sv_link_next == &ent->area)
+		*sv_link_next = ent->area.next;
+	if (sv_link_prev && *sv_link_prev == &ent->area)
+		*sv_link_prev = ent->area.prev;
 	ent->area.prev = ent->area.next = NULL;
 }
 
@@ -283,15 +290,15 @@ void SV_TouchLinks ( edict_t *ent, areanode_t *node )
 	int			old_self, old_other;
 
 // touch linked edicts
+	sv_link_next = &next;
 	for (l = node->trigger_edicts.next ; l != &node->trigger_edicts ; l = next)
 	{
-		//johnfitz -- fixes a crash when a touch function deletes an entity which comes later in the list
 		if (!l)
 		{
-			Con_Printf ("SV_TouchLinks: null link\n");
+		// my area got removed out from under me!
+			Con_Printf ("SV_TouchLinks: encountered NULL link!\n");
 			break;
 		}
-		//johnfitz
 
 		next = l->next;
 		touch = EDICT_FROM_AREA(l);
@@ -314,18 +321,12 @@ void SV_TouchLinks ( edict_t *ent, areanode_t *node )
 		pr_global_struct->time = sv.time;
 		PR_ExecuteProgram (touch->v.touch);
 
-		//johnfitz -- the PR_ExecuteProgram above can alter the linked edicts -- fix from tyrquake 
-		if (next != l->next && l->next)
-		{
-			Con_Printf ("SV_TouchLinks: next != l->next\n");
-			next = l->next;
-		}
-		//johnfitz
-
 		pr_global_struct->self = old_self;
 		pr_global_struct->other = old_other;
 	}
 
+	sv_link_next = NULL;
+
 // recurse down both sides
 	if (node->axis == -1)
 		return;