refactor(Core/Movement): follower management of references (#25060)

Co-authored-by: Shauren <shauren.trinity@gmail.com>

src/server/game/Entities/Unit/Unit.cpp

@@ -16,6 +16,7 @@
  */
 
 #include "Unit.h"
+#include "AbstractFollower.h"
 #include "AreaDefines.h"
 #include "ArenaSpectator.h"
 #include "Battlefield.h"
@@ -44,7 +45,6 @@
 #include "MoveSpline.h"
 #include "MoveSplineInit.h"
 #include "MovementGenerator.h"
-#include "AbstractFollower.h"
 #include "ObjectAccessor.h"
 #include "ObjectMgr.h"
 #include "OutdoorPvP.h"
@@ -5530,12 +5530,8 @@ void Unit::RemoveAreaAurasDueToLeaveWorld()
 
 void Unit::RemoveAllFollowers()
 {
-    while (auto* ref = m_FollowingRefMgr.getFirst())
-    {
-        auto* source = ref->GetSource();
-        ref->delink();
-        source->SetTarget(nullptr);
-    }
+    while (!m_followingMe.empty())
+        (*m_followingMe.begin())->SetTarget(nullptr);
 }
 
 void Unit::RemoveAllAuras()

src/server/game/Entities/Unit/Unit.h

@@ -20,8 +20,6 @@
 
 #include "EnumFlag.h"
 #include "EventProcessor.h"
-#include "FollowerRefMgr.h"
-#include "FollowerReference.h"
 #include "HostileRefMgr.h"
 #include "ItemTemplate.h"
 #include "MotionMaster.h"
@@ -74,6 +72,7 @@ class MotionTransport;
 class Vehicle;
 class TransportBase;
 class SpellCastTargets;
+class AbstractFollower;
 
 typedef std::list<Unit*> UnitList;
 typedef std::list< std::pair<Aura*, uint8> > DispelChargesList;
@@ -1881,9 +1880,9 @@ public:
     [[nodiscard]] bool IsInDisallowedMountForm() const;
 
     // Followers
-    void AddFollower(FollowerReference* ref) { m_FollowingRefMgr.insertFirst(ref); }
+    void FollowerAdded(AbstractFollower* f) { m_followingMe.insert(f); }
+    void FollowerRemoved(AbstractFollower* f) { m_followingMe.erase(f); }
     [[nodiscard]] virtual float GetFollowAngle() const { return static_cast<float>(M_PI / 2); }
-    void RemoveFollower(FollowerReference* /*ref*/ ) { /* nothing to do yet */ }
     void RemoveAllFollowers();
 
     // Pets, guardians, minions...
@@ -2229,7 +2228,7 @@ private:
     // Manage all Units that are threatened by us
     HostileRefMgr m_HostileRefMgr;
 
-    FollowerRefMgr m_FollowingRefMgr;
+    std::unordered_set<AbstractFollower*> m_followingMe;
 
     Unit* m_comboTarget;
     int8 m_comboPoints;

src/server/game/Movement/AbstractFollower.cpp

@@ -20,9 +20,13 @@
 
 void AbstractFollower::SetTarget(Unit* unit)
 {
-    if (unit == GetTarget())
+    if (unit == _target)
         return;
 
-    i_target.link(unit, this);
-    _target = i_target.getTarget();
+    if (_target)
+        _target->FollowerRemoved(this);
+
+    _target = unit;
+    if (_target)
+        _target->FollowerAdded(this);
 }

src/server/game/Movement/AbstractFollower.h

@@ -18,8 +18,6 @@
 #ifndef ACORE_ABSTRACTFOLLOWER_H
 #define ACORE_ABSTRACTFOLLOWER_H
 
-#include "FollowerReference.h"
-
 class Unit;
 
 class AbstractFollower
@@ -29,15 +27,10 @@ public:
     virtual ~AbstractFollower() { SetTarget(nullptr); }
 
     void SetTarget(Unit* unit);
-    Unit* GetTarget() const { return _target; }
-    bool IsTargetValid() const { return i_target.isValid(); }
-
-    virtual void stopFollowing() { }
+    [[nodiscard]] Unit* GetTarget() const { return _target; }
 
+private:
     Unit* _target = nullptr;
-
-protected:
-    FollowerReference i_target;
 };
 
 #endif

src/server/game/Movement/FollowerRefMgr.h

@@ -1,29 +0,0 @@
-/*
- * This file is part of the AzerothCore Project. See AUTHORS file for Copyright information
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
- * more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-
-#ifndef _FOLLOWERREFMANAGER
-#define _FOLLOWERREFMANAGER
-
-#include "RefMgr.h"
-
-class Unit;
-class AbstractFollower;
-
-class FollowerRefMgr : public RefMgr<Unit, AbstractFollower>
-{
-};
-#endif

src/server/game/Movement/FollowerReference.cpp

@@ -1,35 +0,0 @@
-/*
- * This file is part of the AzerothCore Project. See AUTHORS file for Copyright information
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
- * more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include "FollowerReference.h"
-#include "AbstractFollower.h"
-#include "Unit.h"
-
-void FollowerReference::targetObjectBuildLink()
-{
-    getTarget()->AddFollower(this);
-}
-
-void FollowerReference::targetObjectDestroyLink()
-{
-    getTarget()->RemoveFollower(this);
-}
-
-void FollowerReference::sourceObjectDestroyLink()
-{
-    GetSource()->stopFollowing();
-}

src/server/game/Movement/FollowerReference.h

@@ -1,33 +0,0 @@
-/*
- * This file is part of the AzerothCore Project. See AUTHORS file for Copyright information
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
- * more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-
-#ifndef _FOLLOWERREFERENCE_H
-#define _FOLLOWERREFERENCE_H
-
-#include "Reference.h"
-
-class AbstractFollower;
-class Unit;
-
-class FollowerReference : public Reference<Unit, AbstractFollower>
-{
-protected:
-    void targetObjectBuildLink() override;
-    void targetObjectDestroyLink() override;
-    void sourceObjectDestroyLink() override;
-};
-#endif

src/server/game/Movement/MovementGenerators/TargetedMovementGenerator.cpp

@@ -85,7 +85,7 @@ void ChaseMovementGenerator<T>::DistanceYourself(T* owner, float distance)
         i_path = std::make_unique<PathGenerator>(owner);
 
     float x, y, z;
-    i_target->GetNearPoint(owner, x, y, z, owner->GetBoundaryRadius(), distance, i_target->GetAngle(owner));
+    GetTarget()->GetNearPoint(owner, x, y, z, owner->GetBoundaryRadius(), distance, GetTarget()->GetAngle(owner));
     if (DispatchSplineToPosition(owner, x, y, z, false, false, 0.f, false, false))
     {
         m_currentMode = CHASE_MODE_DISTANCING;
@@ -110,7 +110,7 @@ bool ChaseMovementGenerator<T>::DispatchSplineToPosition(T* owner, float x, floa
 
     // For pets, treat incomplete paths as failures to avoid clipping through geometry
     // Players and Player-controlled units have more erratic movement, skip failure
-    if (cOwner && (cOwner->IsPet() || cOwner->IsControlledByPlayer()) && !i_target.getTarget()->IsCharmedOwnedByPlayerOrPlayer())
+    if (cOwner && (cOwner->IsPet() || cOwner->IsControlledByPlayer()) && !GetTarget()->IsCharmedOwnedByPlayerOrPlayer())
         if (pathType & PATHFIND_INCOMPLETE)
             pathFailed = true;
 
@@ -118,7 +118,7 @@ bool ChaseMovementGenerator<T>::DispatchSplineToPosition(T* owner, float x, floa
     {
         if (cOwner)
         {
-            cOwner->SetCannotReachTarget(i_target.getTarget()->GetGUID());
+            cOwner->SetCannotReachTarget(GetTarget()->GetGUID());
 
             if (cOwner->IsPet() || cOwner->IsControlledByPlayer())
                 cOwner->AttackStop();
@@ -142,7 +142,7 @@ bool ChaseMovementGenerator<T>::DispatchSplineToPosition(T* owner, float x, floa
     Movement::MoveSplineInit init(owner);
     init.MovebyPath(i_path->GetPath());
     if (target)
-        init.SetFacing(i_target.getTarget());
+        init.SetFacing(GetTarget());
     init.SetWalk(walk);
     init.Launch();
 
@@ -152,7 +152,7 @@ bool ChaseMovementGenerator<T>::DispatchSplineToPosition(T* owner, float x, floa
 template<class T>
 bool ChaseMovementGenerator<T>::DoUpdate(T* owner, uint32 time_diff)
 {
-    if (!i_target.isValid() || !i_target->IsInWorld() || !owner->IsInMap(i_target.getTarget()))
+    if (!GetTarget() || !GetTarget()->IsInWorld() || !owner->IsInMap(GetTarget()))
         return false;
 
     if (!owner || !owner->IsAlive())
@@ -194,11 +194,11 @@ bool ChaseMovementGenerator<T>::DoUpdate(T* owner, uint32 time_diff)
 
     bool forceDest =
         //(cOwner && (cOwner->isWorldBoss() || cOwner->IsDungeonBoss())) || // force for all bosses, even not in instances
-        (i_target->IsPlayer() && i_target->ToPlayer()->IsGameMaster()) || // for .npc follow
+        (GetTarget()->IsPlayer() && GetTarget()->ToPlayer()->IsGameMaster()) || // for .npc follow
         (owner->CanFly())
         ; // closes "bool forceDest", that way it is more appropriate, so we can comment out crap whenever we need to
 
-    Unit* target = i_target.getTarget();
+    Unit* target = GetTarget();
 
     bool mutualChase = IsMutualChase(owner, target);
     bool const mutualTarget = target->GetVictim() == owner;
@@ -414,7 +414,7 @@ void ChaseMovementGenerator<T>::MovementInform(T* owner)
         {
             // Pass back the GUIDLow of the target. If it is pet's owner then PetAI will handle
             if (CreatureAI* AI = owner->ToCreature()->AI())
-                AI->MovementInform(CHASE_MOTION_TYPE, i_target.getTarget()->GetGUID().GetCounter());
+                AI->MovementInform(CHASE_MOTION_TYPE, GetTarget()->GetGUID().GetCounter());
             break;
         }
         case CHASE_MODE_DISTANCING:
@@ -552,14 +552,14 @@ bool FollowMovementGenerator<T>::PositionOkay(Unit* target, bool isPlayerPet, bo
 template<class T>
 bool FollowMovementGenerator<T>::DoUpdate(T* owner, uint32 time_diff)
 {
-    if (!i_target.isValid() || !i_target->IsInWorld() || !owner->IsInMap(i_target.getTarget()))
+    if (!GetTarget() || !GetTarget()->IsInWorld() || !owner->IsInMap(GetTarget()))
         return false;
 
     if (!owner || !owner->IsAlive())
         return false;
 
     Creature* cOwner = owner->ToCreature();
-    Unit* target = i_target.getTarget();
+    Unit* target = GetTarget();
 
     // the owner might be unable to move (rooted or casting), or we have lost the target, pause movement
     if (owner->HasUnitState(UNIT_STATE_NOT_MOVE) || (cOwner && owner->ToCreature()->IsMovementPreventedByCasting()))
@@ -580,7 +580,7 @@ bool FollowMovementGenerator<T>::DoUpdate(T* owner, uint32 time_diff)
 
     bool forceDest =
         (followingMaster) || // allow pets following their master to cheat while generating paths
-        (i_target->IsPlayer() && i_target->ToPlayer()->IsGameMaster()) // for .npc follow
+        (GetTarget()->IsPlayer() && GetTarget()->ToPlayer()->IsGameMaster()) // for .npc follow
         ; // closes "bool forceDest", that way it is more appropriate, so we can comment out crap whenever we need to
 
     bool targetIsMoving = false;
@@ -725,7 +725,7 @@ void FollowMovementGenerator<T>::MovementInform(T* owner)
 
     // Pass back the GUIDLow of the target. If it is pet's owner then PetAI will handle
     if (CreatureAI* AI = owner->ToCreature()->AI())
-        AI->MovementInform(FOLLOW_MOTION_TYPE, i_target.getTarget()->GetGUID().GetCounter());
+        AI->MovementInform(FOLLOW_MOTION_TYPE, GetTarget()->GetGUID().GetCounter());
 }
 
 //-----------------------------------------------//

src/server/game/Movement/MovementGenerators/TargetedMovementGenerator.h

@@ -25,8 +25,6 @@
 #include "Timer.h"
 #include "Unit.h"
 
-using TargetedMovementGeneratorBase = AbstractFollower;
-
 enum ChaseMovementMode
 {
     CHASE_MODE_NORMAL,      // chasing target