Add helper for clearing an item and using it's old value

Used when moving from one persistent variable to another where we want the source variable to be marked empty. Defining as a function instead of move constructor/assignment operator as we only really need to mark the source for xvalues. Detecting that in the constructor/assignment would be needlessly complicated.

Source/controls/plrctrls.cpp

@@ -1817,14 +1817,12 @@ bool TryDropItem()
 
 	if (currlevel == 0) {
 		if (UseItemOpensHive(myPlayer.HoldItem, myPlayer.position.tile)) {
-			NetSendCmdPItem(true, CMD_PUTITEM, { 79, 61 }, myPlayer.HoldItem);
-			myPlayer.HoldItem.Clear();
+			NetSendCmdPItem(true, CMD_PUTITEM, { 79, 61 }, myPlayer.HoldItem.pop());
 			NewCursor(CURSOR_HAND);
 			return true;
 		}
 		if (UseItemOpensCrypt(myPlayer.HoldItem, myPlayer.position.tile)) {
-			NetSendCmdPItem(true, CMD_PUTITEM, { 35, 20 }, myPlayer.HoldItem);
-			myPlayer.HoldItem.Clear();
+			NetSendCmdPItem(true, CMD_PUTITEM, { 35, 20 }, myPlayer.HoldItem.pop());
 			NewCursor(CURSOR_HAND);
 			return true;
 		}

Source/inv.cpp

@@ -437,10 +437,8 @@ void CheckInvPaste(Player &player, Point cursorPosition)
 		};
 		inv_body_loc slot = iLocToInvLoc(il);
 		Item previouslyEquippedItem = player.InvBody[slot];
-		ChangeEquipment(player, slot, player.HoldItem);
-		if (previouslyEquippedItem.isEmpty()) {
-			player.HoldItem.Clear();
-		} else {
+		ChangeEquipment(player, slot, player.HoldItem.pop());
+		if (!previouslyEquippedItem.isEmpty()) {
 			player.HoldItem = previouslyEquippedItem;
 		}
 		break;
@@ -459,10 +457,8 @@ void CheckInvPaste(Player &player, Point cursorPosition)
 		if (dequipTwoHandedWeapon) {
 			RemoveEquipment(player, otherHand, false);
 		}
-		ChangeEquipment(player, pasteHand, player.HoldItem);
-		if (previouslyEquippedItem.isEmpty()) {
-			player.HoldItem.Clear();
-		} else {
+		ChangeEquipment(player, pasteHand, player.HoldItem.pop());
+		if (!previouslyEquippedItem.isEmpty()) {
 			player.HoldItem = previouslyEquippedItem;
 		}
 		break;
@@ -487,10 +483,8 @@ void CheckInvPaste(Player &player, Point cursorPosition)
 
 		if (player.InvBody[INVLOC_HAND_RIGHT].isEmpty()) {
 			Item previouslyEquippedItem = player.InvBody[INVLOC_HAND_LEFT];
-			ChangeEquipment(player, INVLOC_HAND_LEFT, player.HoldItem);
-			if (previouslyEquippedItem.isEmpty()) {
-				player.HoldItem.Clear();
-			} else {
+			ChangeEquipment(player, INVLOC_HAND_LEFT, player.HoldItem.pop());
+			if (!previouslyEquippedItem.isEmpty()) {
 				player.HoldItem = previouslyEquippedItem;
 			}
 		} else {
@@ -523,15 +517,13 @@ void CheckInvPaste(Player &player, Point cursorPosition)
 			} else {
 				int invIndex = player._pNumInv;
 				player._pGold += player.HoldItem._ivalue;
-				player.InvList[invIndex] = std::move(player.HoldItem);
-				player.HoldItem.Clear();
+				player.InvList[invIndex] = player.HoldItem.pop();
 				player._pNumInv++;
 				player.InvGrid[ii] = player._pNumInv;
 			}
 		} else {
 			if (it == 0) {
-				player.InvList[player._pNumInv] = std::move(player.HoldItem);
-				player.HoldItem.Clear();
+				player.InvList[player._pNumInv] = player.HoldItem.pop();
 				player._pNumInv++;
 				it = player._pNumInv;
 			} else {
@@ -560,8 +552,7 @@ void CheckInvPaste(Player &player, Point cursorPosition)
 	case ILOC_BELT: {
 		int ii = r - SLOTXY_BELT_FIRST;
 		if (player.SpdList[ii].isEmpty()) {
-			player.SpdList[ii] = std::move(player.HoldItem);
-			player.HoldItem.Clear();
+			player.SpdList[ii] = player.HoldItem.pop();
 		} else {
 			std::swap(player.SpdList[ii], player.HoldItem);
 			if (player.HoldItem._itype == ItemType::Gold)

Source/items.h

@@ -242,6 +242,16 @@ struct Item {
 	uint32_t dwBuff = 0;
 	ItemSpecialEffectHf _iDamAcFlags = ItemSpecialEffectHf::None;
 
+	/**
+	 * @brief Clears this item and returns the old value
+	 */
+	Item pop() &
+	{
+		Item temp = std::move(*this);
+		Clear();
+		return temp;
+	}
+
 	/**
 	 * @brief Resets the item so isEmpty() returns true without needing to reinitialise the whole object
 	 */

Source/player.cpp

@@ -1936,8 +1936,7 @@ void Player::RemoveInvItem(int iv, bool calcScrolls)
 
 	// If the item at the end of inventory array isn't the one we removed, we need to swap its position in the array with the removed item
 	if (_pNumInv > 0 && _pNumInv != iv) {
-		InvList[iv] = std::move(InvList[_pNumInv]);
-		InvList[_pNumInv].Clear();
+		InvList[iv] = InvList[_pNumInv].pop();
 
 		for (int8_t &itemIndex : InvGrid) {
 			if (itemIndex == _pNumInv + 1) {
@@ -3175,8 +3174,7 @@ StartPlayerKill(int pnum, int earflag)
 						Direction pdd = player._pdir;
 						for (auto &item : player.InvBody) {
 							pdd = Left(pdd);
-							DeadItem(player, std::move(item), Displacement(pdd));
-							item.Clear();
+							DeadItem(player, item.pop(), Displacement(pdd));
 						}
 
 						CalcPlrInv(player, false);

Source/qol/stash.cpp

@@ -127,8 +127,7 @@ void CheckStashPaste(Point cursorPosition)
 	player.HoldItem.position = firstSlot + Displacement { 0, itemSize.height - 1 };
 
 	if (stashIndex == StashStruct::EmptyCell) {
-		Stash.stashList.emplace_back(std::move(player.HoldItem));
-		player.HoldItem.Clear();
+		Stash.stashList.emplace_back(player.HoldItem.pop());
 		// stashList will have at most 10 000 items, up to 65 535 are supported with uint16_t indexes
 		stashIndex = static_cast<uint16_t>(Stash.stashList.size() - 1);
 	} else {