Fix potential destruction crashes (#5095)

* Fix potential destruction crashes

* Fix destructors accessing destroyted objects
* Fix cPlayer not destroying windows (Destroyed never called)
* Tentatively fixes #4608, fixes #3236, fixes #3262
- Remove cEntity::Destroyed() and replace with cEntity::OnRemoveFromWorld()

* Add missing call to OnRemoveFromWorld

src/BlockEntities/BeaconEntity.cpp

@@ -271,6 +271,20 @@ void cBeaconEntity::CopyFrom(const cBlockEntity & a_Src)
 
 
 
+void cBeaconEntity::OnRemoveFromWorld()
+{
+	const auto Window = GetWindow();
+	if (Window != nullptr)
+	{
+		// Tell window its owner is destroyed:
+		Window->OwnerDestroyed();
+	}
+}
+
+
+
+
+
 void cBeaconEntity::SendTo(cClientHandle & a_Client)
 {
 	a_Client.SendUpdateBlockEntity(*this);
@@ -316,6 +330,3 @@ bool cBeaconEntity::UsedBy(cPlayer * a_Player)
 	}
 	return true;
 }
-
-
-

src/BlockEntities/BeaconEntity.h

@@ -29,6 +29,7 @@ public:  // tolua_export
 
 	// cBlockEntity overrides:
 	virtual void CopyFrom(const cBlockEntity & a_Src) override;
+	virtual void OnRemoveFromWorld() override;
 	virtual void SendTo(cClientHandle & a_Client) override;
 	virtual bool Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk) override;
 	virtual bool UsedBy(cPlayer * a_Player) override;

src/BlockEntities/BlockEntity.cpp

@@ -28,56 +28,52 @@
 
 
 
-void cBlockEntity::SetPos(Vector3i a_NewPos)
+cBlockEntity::cBlockEntity(const BLOCKTYPE a_BlockType, const NIBBLETYPE a_BlockMeta, const Vector3i a_Pos, cWorld * const a_World) :
+	m_Pos(a_Pos),
+	m_RelX(a_Pos.x - cChunkDef::Width * FAST_FLOOR_DIV(a_Pos.x, cChunkDef::Width)),
+	m_RelZ(a_Pos.z - cChunkDef::Width * FAST_FLOOR_DIV(a_Pos.z, cChunkDef::Width)),
+	m_BlockType(a_BlockType),
+	m_BlockMeta(a_BlockMeta),
+	m_World(a_World)
 {
-	ASSERT(m_World == nullptr);  // Cannot move block entities that represent world blocks (only use this for cBlockArea's BEs)
-	m_Pos = a_NewPos;
 }
 
 
 
 
 
-bool cBlockEntity::IsBlockEntityBlockType(BLOCKTYPE a_BlockType)
+OwnedBlockEntity cBlockEntity::Clone(const Vector3i a_Pos)
 {
-	switch (a_BlockType)
-	{
-		case E_BLOCK_BEACON:
-		case E_BLOCK_BED:
-		case E_BLOCK_BREWING_STAND:
-		case E_BLOCK_CHEST:
-		case E_BLOCK_COMMAND_BLOCK:
-		case E_BLOCK_DISPENSER:
-		case E_BLOCK_DROPPER:
-		case E_BLOCK_ENCHANTMENT_TABLE:
-		case E_BLOCK_ENDER_CHEST:
-		case E_BLOCK_END_PORTAL:
-		case E_BLOCK_FLOWER_POT:
-		case E_BLOCK_FURNACE:
-		case E_BLOCK_HEAD:
-		case E_BLOCK_HOPPER:
-		case E_BLOCK_JUKEBOX:
-		case E_BLOCK_LIT_FURNACE:
-		case E_BLOCK_MOB_SPAWNER:
-		case E_BLOCK_NOTE_BLOCK:
-		case E_BLOCK_SIGN_POST:
-		case E_BLOCK_TRAPPED_CHEST:
-		case E_BLOCK_WALLSIGN:
-		{
-			return true;
-		}
-		default:
-		{
-			return false;
-		}
-	}
+	auto res = CreateByBlockType(m_BlockType, m_BlockMeta, a_Pos, nullptr);
+	res->CopyFrom(*this);
+	return res;
 }
 
 
 
 
 
-OwnedBlockEntity cBlockEntity::CreateByBlockType(BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta, Vector3i a_Pos, cWorld * a_World)
+cItems cBlockEntity::ConvertToPickups() const
+{
+	return {};
+}
+
+
+
+
+
+void cBlockEntity::CopyFrom(const cBlockEntity & a_Src)
+{
+	// Nothing to copy, but check that we're copying the right entity:
+	ASSERT(m_BlockType == a_Src.m_BlockType);
+	ASSERT(m_BlockMeta == a_Src.m_BlockMeta);
+}
+
+
+
+
+
+OwnedBlockEntity cBlockEntity::CreateByBlockType(const BLOCKTYPE a_BlockType, const NIBBLETYPE a_BlockMeta, const Vector3i a_Pos, cWorld * const a_World)
 {
 	switch (a_BlockType)
 	{
@@ -117,29 +113,82 @@ OwnedBlockEntity cBlockEntity::CreateByBlockType(BLOCKTYPE a_BlockType, NIBBLETY
 
 
 
-OwnedBlockEntity cBlockEntity::Clone(Vector3i a_Pos)
+void cBlockEntity::Destroy()
 {
-	auto res = CreateByBlockType(m_BlockType, m_BlockMeta, a_Pos, nullptr);
-	res->CopyFrom(*this);
-	return res;
 }
 
 
 
 
 
-cItems cBlockEntity::ConvertToPickups() const
+bool cBlockEntity::IsBlockEntityBlockType(const BLOCKTYPE a_BlockType)
 {
-	return {};
+	switch (a_BlockType)
+	{
+		case E_BLOCK_BEACON:
+		case E_BLOCK_BED:
+		case E_BLOCK_BREWING_STAND:
+		case E_BLOCK_CHEST:
+		case E_BLOCK_COMMAND_BLOCK:
+		case E_BLOCK_DISPENSER:
+		case E_BLOCK_DROPPER:
+		case E_BLOCK_ENCHANTMENT_TABLE:
+		case E_BLOCK_ENDER_CHEST:
+		case E_BLOCK_END_PORTAL:
+		case E_BLOCK_FLOWER_POT:
+		case E_BLOCK_FURNACE:
+		case E_BLOCK_HEAD:
+		case E_BLOCK_HOPPER:
+		case E_BLOCK_JUKEBOX:
+		case E_BLOCK_LIT_FURNACE:
+		case E_BLOCK_MOB_SPAWNER:
+		case E_BLOCK_NOTE_BLOCK:
+		case E_BLOCK_SIGN_POST:
+		case E_BLOCK_TRAPPED_CHEST:
+		case E_BLOCK_WALLSIGN:
+		{
+			return true;
+		}
+		default:
+		{
+			return false;
+		}
+	}
 }
 
 
 
 
 
-void cBlockEntity::CopyFrom(const cBlockEntity & a_Src)
+void cBlockEntity::OnRemoveFromWorld()
 {
-	// Nothing to copy, but check that we're copying the right entity:
-	ASSERT(m_BlockType == a_Src.m_BlockType);
-	ASSERT(m_BlockMeta == a_Src.m_BlockMeta);
+}
+
+
+
+
+
+void cBlockEntity::SetPos(const Vector3i a_NewPos)
+{
+	ASSERT(m_World == nullptr);  // Cannot move block entities that represent world blocks (only use this for cBlockArea's BEs)
+	m_Pos = a_NewPos;
+}
+
+
+
+
+
+void cBlockEntity::SetWorld(cWorld * const a_World)
+{
+	m_World = a_World;
+}
+
+
+
+
+
+bool cBlockEntity::Tick(const std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
+{
+	UNUSED(a_Dt);
+	return false;
 }

src/BlockEntities/BlockEntity.h

@@ -24,41 +24,14 @@ using cBlockEntities = std::unordered_map<size_t, OwnedBlockEntity>;
 class cBlockEntity
 {
 protected:
-	cBlockEntity(BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta, Vector3i a_Pos, cWorld * a_World) :
-		m_Pos(a_Pos),
-		m_RelX(a_Pos.x - cChunkDef::Width * FAST_FLOOR_DIV(a_Pos.x, cChunkDef::Width)),
-		m_RelZ(a_Pos.z - cChunkDef::Width * FAST_FLOOR_DIV(a_Pos.z, cChunkDef::Width)),
-		m_BlockType(a_BlockType),
-		m_BlockMeta(a_BlockMeta),
-		m_World(a_World)
-	{
-	}
+
+	cBlockEntity(BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta, Vector3i a_Pos, cWorld * a_World);
 
 public:
 
 	// tolua_end
 
-	virtual ~cBlockEntity() {}  // force a virtual destructor in all descendants
-
-	virtual void Destroy() {}
-
-	void SetWorld(cWorld * a_World)
-	{
-		m_World = a_World;
-	}
-
-	/** Updates the internally stored position.
-	Note that this should not ever be used for world-contained block entities, it is meant only for when BEs in a cBlockArea are manipulated.
-	Asserts that the block entity is not assigned to a world. */
-	void SetPos(Vector3i a_NewPos);
-
-	/** Returns true if the specified blocktype is supposed to have an associated block entity. */
-	static bool IsBlockEntityBlockType(BLOCKTYPE a_BlockType);
-
-	/** Creates a new block entity for the specified block type at the specified absolute pos.
-	If a_World is valid, then the entity is created bound to that world
-	Returns nullptr for unknown block types. */
-	static OwnedBlockEntity CreateByBlockType(BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta, Vector3i a_Pos, cWorld * a_World = nullptr);
+	virtual ~cBlockEntity() = default;  // force a virtual destructor in all descendants
 
 	/** Makes an exact copy of this block entity, except for its m_World (set to nullptr), and at a new position.
 	Uses CopyFrom() to copy the properties. */
@@ -73,6 +46,37 @@ public:
 	Super::CopyFrom(a_Src) to copy the common ones. */
 	virtual void CopyFrom(const cBlockEntity & a_Src);
 
+	/** Creates a new block entity for the specified block type at the specified absolute pos.
+	If a_World is valid, then the entity is created bound to that world
+	Returns nullptr for unknown block types. */
+	static OwnedBlockEntity CreateByBlockType(BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta, Vector3i a_Pos, cWorld * a_World = nullptr);
+
+	virtual void Destroy();
+
+	/** Returns true if the specified blocktype is supposed to have an associated block entity. */
+	static bool IsBlockEntityBlockType(BLOCKTYPE a_BlockType);
+
+	/** Called when the block entity is removed from a world. */
+	virtual void OnRemoveFromWorld();
+
+	/** Sends the packet defining the block entity to the client specified.
+	To send to all eligible clients, use cWorld::BroadcastBlockEntity() */
+	virtual void SendTo(cClientHandle & a_Client) = 0;
+
+	/** Updates the internally stored position.
+	Note that this should not ever be used for world-contained block entities, it is meant only for when BEs in a cBlockArea are manipulated.
+	Asserts that the block entity is not assigned to a world. */
+	void SetPos(Vector3i a_NewPos);
+
+	void SetWorld(cWorld * a_World);
+
+	/** Ticks the entity; returns true if the chunk should be marked as dirty as a result of this ticking. By default does nothing. */
+	virtual bool Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk);
+
+	/** Called when a player uses this entity; should open the UI window.
+	returns true if the use was successful, return false to use the block as a "normal" block */
+	virtual bool UsedBy(cPlayer * a_Player) = 0;
+
 	// tolua_begin
 
 	// Position, in absolute block coordinates:
@@ -95,21 +99,6 @@ public:
 
 	// tolua_end
 
-	/** Called when a player uses this entity; should open the UI window.
-	returns true if the use was successful, return false to use the block as a "normal" block */
-	virtual bool UsedBy( cPlayer * a_Player) = 0;
-
-	/** Sends the packet defining the block entity to the client specified.
-	To send to all eligible clients, use cWorld::BroadcastBlockEntity() */
-	virtual void SendTo(cClientHandle & a_Client) = 0;
-
-	/** Ticks the entity; returns true if the chunk should be marked as dirty as a result of this ticking. By default does nothing. */
-	virtual bool Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
-	{
-		UNUSED(a_Dt);
-		return false;
-	}
-
 
 protected:
 

src/BlockEntities/BrewingstandEntity.cpp

@@ -13,7 +13,6 @@
 
 cBrewingstandEntity::cBrewingstandEntity(BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta, Vector3i a_Pos, cWorld * a_World):
 	Super(a_BlockType, a_BlockMeta, a_Pos, ContentsWidth, ContentsHeight, a_World),
-	m_IsDestroyed(false),
 	m_IsBrewing(false),
 	m_TimeBrewed(0),
 	m_RemainingFuel(0)
@@ -25,30 +24,6 @@ cBrewingstandEntity::cBrewingstandEntity(BLOCKTYPE a_BlockType, NIBBLETYPE a_Blo
 
 
 
-cBrewingstandEntity::~cBrewingstandEntity()
-{
-	// Tell window its owner is destroyed
-	cWindow * Window = GetWindow();
-	if (Window != nullptr)
-	{
-		Window->OwnerDestroyed();
-	}
-}
-
-
-
-
-
-void cBrewingstandEntity::Destroy()
-{
-	m_IsDestroyed = true;
-	Super::Destroy();
-}
-
-
-
-
-
 void cBrewingstandEntity::CopyFrom(const cBlockEntity & a_Src)
 {
 	Super::CopyFrom(a_Src);
@@ -70,6 +45,20 @@ void cBrewingstandEntity::CopyFrom(const cBlockEntity & a_Src)
 
 
 
+void cBrewingstandEntity::OnRemoveFromWorld()
+{
+	const auto Window = GetWindow();
+	if (Window != nullptr)
+	{
+		// Tell window its owner is destroyed:
+		Window->OwnerDestroyed();
+	}
+}
+
+
+
+
+
 void cBrewingstandEntity::SendTo(cClientHandle & a_Client)
 {
 	// Nothing needs to be sent
@@ -206,11 +195,6 @@ void cBrewingstandEntity::OnSlotChanged(cItemGrid * a_ItemGrid, int a_SlotNum)
 {
 	Super::OnSlotChanged(a_ItemGrid, a_SlotNum);
 
-	if (m_IsDestroyed)
-	{
-		return;
-	}
-
 	ASSERT(a_ItemGrid == &m_Contents);
 
 	// Check for fuel

src/BlockEntities/BrewingstandEntity.h

@@ -8,6 +8,7 @@
 
 
 
+
 class cClientHandle;
 
 
@@ -43,11 +44,9 @@ public:
 	/** Constructor used for normal operation */
 	cBrewingstandEntity(BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta, Vector3i a_Pos, cWorld * a_World);
 
-	virtual ~cBrewingstandEntity() override;
-
-	//  cBlockEntity overrides:
-	virtual void Destroy() override;
+	// cBlockEntity overrides:
 	virtual void CopyFrom(const cBlockEntity & a_Src) override;
+	virtual void OnRemoveFromWorld() override;
 	virtual void SendTo(cClientHandle & a_Client) override;
 	virtual bool Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk) override;
 	virtual bool UsedBy(cPlayer * a_Player) override;
@@ -110,12 +109,8 @@ public:
 	/** Gets the recipes. Will be called if the brewing stand gets loaded from the world. */
 	void LoadRecipes(void);
 
-
 protected:
 
-	/** Set to true when the brewing stand entity has been destroyed to prevent the block being set again */
-	bool m_IsDestroyed;
-
 	/** Set to true if the brewing stand is brewing an item */
 	bool m_IsBrewing;
 

src/BlockEntities/ChestEntity.cpp

@@ -32,22 +32,6 @@ cChestEntity::cChestEntity(BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta, Vector
 
 
 
-cChestEntity::~cChestEntity()
-{
-	if (m_Neighbour != nullptr)
-	{
-		// Neighbour may share a window with us, force the window shut
-		m_Neighbour->DestroyWindow();
-		m_Neighbour->m_Neighbour = nullptr;
-	}
-
-	DestroyWindow();
-}
-
-
-
-
-
 void cChestEntity::CopyFrom(const cBlockEntity & a_Src)
 {
 	Super::CopyFrom(a_Src);
@@ -63,6 +47,22 @@ void cChestEntity::CopyFrom(const cBlockEntity & a_Src)
 
 
 
+void cChestEntity::OnRemoveFromWorld()
+{
+	if (m_Neighbour != nullptr)
+	{
+		// Neighbour may share a window with us, force the window shut:
+		m_Neighbour->DestroyWindow();
+		m_Neighbour->m_Neighbour = nullptr;
+	}
+
+	DestroyWindow();
+}
+
+
+
+
+
 void cChestEntity::SendTo(cClientHandle & a_Client)
 {
 	// Send a dummy "number of players with chest open" packet to make the chest visible:
@@ -199,11 +199,10 @@ void cChestEntity::OpenNewWindow(void)
 
 void cChestEntity::DestroyWindow()
 {
-	cWindow * Window = GetWindow();
+	const auto Window = GetWindow();
 	if (Window != nullptr)
 	{
 		Window->OwnerDestroyed();
-		CloseWindow();
 	}
 }
 

src/BlockEntities/ChestEntity.h

@@ -37,10 +37,9 @@ public:
 	/** Constructor used for normal operation */
 	cChestEntity(BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta, Vector3i a_Pos, cWorld * a_World);
 
-	virtual ~cChestEntity() override;
-
 	// cBlockEntity overrides:
 	virtual void CopyFrom(const cBlockEntity & a_Src) override;
+	virtual void OnRemoveFromWorld() override;
 	virtual void SendTo(cClientHandle & a_Client) override;
 	virtual bool UsedBy(cPlayer * a_Player) override;
 

src/BlockEntities/DropSpenserEntity.cpp

@@ -26,20 +26,6 @@ cDropSpenserEntity::cDropSpenserEntity(BLOCKTYPE a_BlockType, NIBBLETYPE a_Block
 
 
 
-cDropSpenserEntity::~cDropSpenserEntity()
-{
-	// Tell window its owner is destroyed
-	cWindow * Window = GetWindow();
-	if (Window != nullptr)
-	{
-		Window->OwnerDestroyed();
-	}
-}
-
-
-
-
-
 void cDropSpenserEntity::AddDropSpenserDir(Vector3i & a_RelCoord, NIBBLETYPE a_Direction)
 {
 	switch (a_Direction & E_META_DROPSPENSER_FACING_MASK)
@@ -132,6 +118,20 @@ void cDropSpenserEntity::CopyFrom(const cBlockEntity & a_Src)
 
 
 
+void cDropSpenserEntity::OnRemoveFromWorld()
+{
+	const auto Window = GetWindow();
+	if (Window != nullptr)
+	{
+		// Tell window its owner is destroyed:
+		Window->OwnerDestroyed();
+	}
+}
+
+
+
+
+
 bool cDropSpenserEntity::Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
 {
 	UNUSED(a_Dt);

src/BlockEntities/DropSpenserEntity.h

@@ -43,10 +43,10 @@ public:
 	// tolua_end
 
 	cDropSpenserEntity(BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta, Vector3i a_Pos, cWorld * a_World);
-	virtual ~cDropSpenserEntity() override;
 
 	// cBlockEntity overrides:
 	virtual void CopyFrom(const cBlockEntity & a_Src) override;
+	virtual void OnRemoveFromWorld() override;
 	virtual bool Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk) override;
 	virtual void SendTo(cClientHandle & a_Client) override;
 	virtual bool UsedBy(cPlayer * a_Player) override;

src/BlockEntities/EnderChestEntity.cpp

@@ -25,23 +25,23 @@ cEnderChestEntity::cEnderChestEntity(BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMe
 
 
 
-cEnderChestEntity::~cEnderChestEntity()
+void cEnderChestEntity::SendTo(cClientHandle & a_Client)
 {
-	cWindow * Window = GetWindow();
-	if (Window != nullptr)
-	{
-		Window->OwnerDestroyed();
-	}
+	// Send a dummy "number of players with chest open" packet to make the chest visible:
+	a_Client.SendBlockAction(m_Pos.x, m_Pos.y, m_Pos.z, 1, 0, m_BlockType);
 }
 
 
 
 
 
-void cEnderChestEntity::SendTo(cClientHandle & a_Client)
+void cEnderChestEntity::OnRemoveFromWorld()
 {
-	// Send a dummy "number of players with chest open" packet to make the chest visible:
-	a_Client.SendBlockAction(m_Pos.x, m_Pos.y, m_Pos.z, 1, 0, m_BlockType);
+	const auto Window = GetWindow();
+	if (Window != nullptr)
+	{
+		Window->OwnerDestroyed();
+	}
 }
 
 

src/BlockEntities/EnderChestEntity.h

@@ -20,9 +20,9 @@ class cEnderChestEntity :
 public:  // tolua_export
 
 	cEnderChestEntity(BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta, Vector3i a_Pos, cWorld * a_World);
-	virtual ~cEnderChestEntity() override;
 
 	// cBlockEntity overrides:
+	virtual void OnRemoveFromWorld() override;
 	virtual bool UsedBy(cPlayer * a_Player) override;
 	virtual void SendTo(cClientHandle & a_Client) override;
 

src/BlockEntities/FlowerPotEntity.cpp

@@ -23,18 +23,9 @@ cFlowerPotEntity::cFlowerPotEntity(BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta
 
 
 
-void cFlowerPotEntity::Destroy(void)
+cItems cFlowerPotEntity::ConvertToPickups() const
 {
-	// Drop the contents as pickups:
-	if (!m_Item.IsEmpty())
-	{
-		ASSERT(m_World != nullptr);
-		cItems Pickups;
-		Pickups.Add(m_Item);
-		m_World->SpawnItemPickups(Pickups, Vector3d(0.5, 0.5, 0.5) + m_Pos);
-
-		m_Item.Empty();
-	}
+	return cItem(m_Item);
 }
 
 

src/BlockEntities/FlowerPotEntity.h

@@ -43,7 +43,7 @@ public:  // tolua_export
 	// tolua_end
 
 	// cBlockEntity overrides:
-	virtual void Destroy(void) override;
+	virtual cItems ConvertToPickups() const override;
 	virtual void CopyFrom(const cBlockEntity & a_Src) override;
 	virtual bool UsedBy(cPlayer * a_Player) override;
 	virtual void SendTo(cClientHandle & a_Client) override;

src/BlockEntities/FurnaceEntity.cpp

@@ -25,7 +25,6 @@ enum
 cFurnaceEntity::cFurnaceEntity(BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta, Vector3i a_Pos, cWorld * a_World):
 	Super(a_BlockType, a_BlockMeta, a_Pos, ContentsWidth, ContentsHeight, a_World),
 	m_CurrentRecipe(nullptr),
-	m_IsDestroyed(false),
 	m_IsCooking(a_BlockType == E_BLOCK_LIT_FURNACE),
 	m_NeedCookTime(0),
 	m_TimeCooked(0),
@@ -41,30 +40,6 @@ cFurnaceEntity::cFurnaceEntity(BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta, Ve
 
 
 
-cFurnaceEntity::~cFurnaceEntity()
-{
-	// Tell window its owner is destroyed
-	cWindow * Window = GetWindow();
-	if (Window != nullptr)
-	{
-		Window->OwnerDestroyed();
-	}
-}
-
-
-
-
-
-void cFurnaceEntity::Destroy()
-{
-	m_IsDestroyed = true;
-	Super::Destroy();
-}
-
-
-
-
-
 void cFurnaceEntity::CopyFrom(const cBlockEntity & a_Src)
 {
 	Super::CopyFrom(a_Src);
@@ -73,7 +48,6 @@ void cFurnaceEntity::CopyFrom(const cBlockEntity & a_Src)
 	m_CurrentRecipe = src.m_CurrentRecipe;
 	m_FuelBurnTime = src.m_FuelBurnTime;
 	m_IsCooking = src.m_IsCooking;
-	m_IsDestroyed = src.m_IsDestroyed;
 	m_IsLoading = src.m_IsLoading;
 	m_LastInput = src.m_LastInput;
 	m_NeedCookTime = src.m_NeedCookTime;
@@ -85,6 +59,20 @@ void cFurnaceEntity::CopyFrom(const cBlockEntity & a_Src)
 
 
 
+void cFurnaceEntity::OnRemoveFromWorld()
+{
+	const auto Window = GetWindow();
+	if (Window != nullptr)
+	{
+		// Tell window its owner is destroyed:
+		Window->OwnerDestroyed();
+	}
+}
+
+
+
+
+
 void cFurnaceEntity::SendTo(cClientHandle & a_Client)
 {
 	// Nothing needs to be sent
@@ -259,11 +247,6 @@ void cFurnaceEntity::OnSlotChanged(cItemGrid * a_ItemGrid, int a_SlotNum)
 {
 	Super::OnSlotChanged(a_ItemGrid, a_SlotNum);
 
-	if (m_IsDestroyed)
-	{
-		return;
-	}
-
 	if (m_IsLoading)
 	{
 		return;

src/BlockEntities/FurnaceEntity.h

@@ -41,11 +41,9 @@ public:
 	/** Constructor used for normal operation */
 	cFurnaceEntity(BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta, Vector3i a_Pos, cWorld * a_World);
 
-	virtual ~cFurnaceEntity() override;
-
 	// cBlockEntity overrides:
-	virtual void Destroy() override;
 	virtual void CopyFrom(const cBlockEntity & a_Src) override;
+	virtual void OnRemoveFromWorld() override;
 	virtual void SendTo(cClientHandle & a_Client) override;
 	virtual bool Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk) override;
 	virtual bool UsedBy(cPlayer * a_Player) override;
@@ -118,9 +116,6 @@ protected:
 	/** The item that is being smelted */
 	cItem m_LastInput;
 
-	/** Set to true when the furnace entity has been destroyed to prevent the block being set again */
-	bool m_IsDestroyed;
-
 	/** Set to true if the furnace is cooking an item */
 	bool m_IsCooking;