Game/Maps: Clean up instance handling.

- Rename Map::CanEnter to Map::CannotEnter. Return value changed from boolean (true means player can enter) to enum Map::EnterState (CAN_ENTER=0 means player can enter, any other value is a reason for deny).
- Move hack-y player error messages from within Map::CanEnter to the function calling CanEnter as appropriate (primarily WorldSession::HandleAreaTriggerOpcode).
- Modify WorldSession::HandleAreaTriggerOpcode to properly revive the player upon touching the portal leading to the instance they died in even if they are currently unable to zone in. Fixes and closes #15758.
- Modify Player::LoadFromDB to properly spawn players in the instance they logged off in if possible. Fixes and closes #15561.
- Modify permanent save behavior to be blizzlike: Players can always enter an instance they are saved to (assuming there are no map constraints against it), but get a homebind timer if the instance is already in use.

1 files changed, 18 insertions, 42 deletions

diff --git a/src/server/game/Maps/Map.cpp b/src/server/game/Maps/Map.cpp
index 6fbef752228..67abf4af682 100644
--- a/src/server/game/Maps/Map.cpp
+++ b/src/server/game/Maps/Map.cpp
@@ -2947,62 +2947,38 @@ void InstanceMap::InitVisibilityDistance()
 /*
     Do map specific checks to see if the player can enter
 */
-bool InstanceMap::CanEnter(Player* player)
+Map::EnterState InstanceMap::CannotEnter(Player* player)
 {
     if (player->GetMapRef().getTarget() == this)
     {
-        TC_LOG_ERROR("maps", "InstanceMap::CanEnter - player %s(%u) already in map %d, %d, %d!", player->GetName().c_str(), player->GetGUID().GetCounter(), GetId(), GetInstanceId(), GetSpawnMode());
+        TC_LOG_ERROR("maps", "InstanceMap::CannotEnter - player %s(%u) already in map %d, %d, %d!", player->GetName().c_str(), player->GetGUID().GetCounter(), GetId(), GetInstanceId(), GetSpawnMode());
         ABORT();
-        return false;
+        return CANNOT_ENTER_ALREADY_IN_MAP;
     }
 
     // allow GM's to enter
     if (player->IsGameMaster())
-        return Map::CanEnter(player);
+        return Map::CannotEnter(player);
 
     // cannot enter if the instance is full (player cap), GMs don't count
     uint32 maxPlayers = GetMaxPlayers();
     if (GetPlayersCountExceptGMs() >= maxPlayers)
     {
         TC_LOG_WARN("maps", "MAP: Instance '%u' of map '%s' cannot have more than '%u' players. Player '%s' rejected", GetInstanceId(), GetMapName(), maxPlayers, player->GetName().c_str());
-        player->SendTransferAborted(GetId(), TRANSFER_ABORT_MAX_PLAYERS);
-        return false;
+        return CANNOT_ENTER_MAX_PLAYERS;
     }
 
-    // cannot enter while an encounter is in progress
-    // allow if just loading
+    // cannot enter while an encounter is in progress (unless this is a relog, in which case it is permitted)
     if (!player->IsLoading() && IsRaid() && GetInstanceScript() && GetInstanceScript()->IsEncounterInProgress())
-    {
-        player->SendTransferAborted(GetId(), TRANSFER_ABORT_ZONE_IN_COMBAT);
-        return false;
-    }
+        return CANNOT_ENTER_ZONE_IN_COMBAT;
 
-    // cannot enter if instance is in use by another party/soloer that have a
-    // permanent save in the same instance id
+    // cannot enter if player is permanent saved to a different instance id
+    if (InstancePlayerBind* playerBind = player->GetBoundInstance(GetId(), GetDifficulty()))
+        if (playerBind->perm && playerBind->save)
+            if (playerBind->save->GetInstanceId() != GetInstanceId())
+                return CANNOT_ENTER_INSTANCE_BIND_MISMATCH;
 
-    PlayerList const &playerList = GetPlayers();
-
-    if (!playerList.isEmpty())
-        for (PlayerList::const_iterator i = playerList.begin(); i != playerList.end(); ++i)
-            if (Player* iPlayer = i->GetSource())
-            {
-                if (iPlayer->IsGameMaster()) // bypass GMs
-                    continue;
-                if (!player->GetGroup()) // player has not group and there is someone inside, deny entry
-                {
-                    player->SendTransferAborted(GetId(), TRANSFER_ABORT_MAX_PLAYERS);
-                    return false;
-                }
-                // player inside instance has no group or his groups is different to entering player's one, deny entry
-                if (!iPlayer->GetGroup() || iPlayer->GetGroup() != player->GetGroup())
-                {
-                    player->SendTransferAborted(GetId(), TRANSFER_ABORT_MAX_PLAYERS);
-                    return false;
-                }
-                break;
-            }
-
-    return Map::CanEnter(player);
+    return Map::CannotEnter(player);
 }
 
 /*
@@ -3339,21 +3315,21 @@ void BattlegroundMap::InitVisibilityDistance()
     m_VisibilityNotifyPeriod = World::GetVisibilityNotifyPeriodInBGArenas();
 }
 
-bool BattlegroundMap::CanEnter(Player* player)
+Map::EnterState BattlegroundMap::CannotEnter(Player* player)
 {
     if (player->GetMapRef().getTarget() == this)
     {
-        TC_LOG_ERROR("maps", "BGMap::CanEnter - player %u is already in map!", player->GetGUID().GetCounter());
+        TC_LOG_ERROR("maps", "BGMap::CannotEnter - player %u is already in map!", player->GetGUID().GetCounter());
         ABORT();
-        return false;
+        return CANNOT_ENTER_ALREADY_IN_MAP;
     }
 
     if (player->GetBattlegroundId() != GetInstanceId())
-        return false;
+        return CANNOT_ENTER_INSTANCE_BIND_MISMATCH;
 
     // player number limit is checked in bgmgr, no need to do it here
 
-    return Map::CanEnter(player);
+    return Map::CannotEnter(player);
 }
 
 bool BattlegroundMap::AddPlayerToMap(Player* player)