Resolve moved references loaded from a save game

apps/openmw/mwworld/cells.cpp

@@ -1,5 +1,7 @@
 #include "cells.hpp"
 
+#include <iostream>
+
 #include <components/esm/esmreader.hpp>
 #include <components/esm/esmwriter.hpp>
 #include <components/esm/defs.hpp>
@@ -303,6 +305,29 @@ void MWWorld::Cells::write (ESM::ESMWriter& writer, Loading::Listener& progress)
         }
 }
 
+struct GetCellStoreCallback : public MWWorld::CellStore::GetCellStoreCallback
+{
+public:
+    GetCellStoreCallback(MWWorld::Cells& cells)
+        : mCells(cells)
+    {
+    }
+
+    MWWorld::Cells& mCells;
+
+    virtual MWWorld::CellStore* getCellStore(const ESM::CellId& cellId)
+    {
+        try
+        {
+            return mCells.getCell(cellId);
+        }
+        catch (...)
+        {
+            return NULL;
+        }
+    }
+};
+
 bool MWWorld::Cells::readRecord (ESM::ESMReader& reader, uint32_t type,
     const std::map<int, int>& contentFileMap)
 {
@@ -320,9 +345,9 @@ bool MWWorld::Cells::readRecord (ESM::ESMReader& reader, uint32_t type,
         catch (...)
         {
             // silently drop cells that don't exist anymore
+            std::cerr << "Dropping state for cell " << state.mId.mWorldspace << " (cell no longer exists)" << std::endl;
             reader.skipRecord();
             return true;
-            /// \todo log
         }
 
         state.load (reader);
@@ -334,7 +359,9 @@ bool MWWorld::Cells::readRecord (ESM::ESMReader& reader, uint32_t type,
         if (cellStore->getState()!=CellStore::State_Loaded)
             cellStore->load ();
 
-        cellStore->readReferences (reader, contentFileMap);
+        GetCellStoreCallback callback(*this);
+
+        cellStore->readReferences (reader, contentFileMap, &callback);
 
         return true;
     }

apps/openmw/mwworld/cellstore.cpp

@@ -613,6 +613,28 @@ namespace MWWorld
         mFogState->load(reader);
     }
 
+    struct SearchByRefNumVisitor
+    {
+        LiveCellRefBase* mFound;
+        ESM::RefNum mRefNumToFind;
+
+        SearchByRefNumVisitor(const ESM::RefNum& toFind)
+            : mFound(NULL)
+            , mRefNumToFind(toFind)
+        {
+        }
+
+        bool operator()(const MWWorld::Ptr& ptr)
+        {
+            if (ptr.getCellRef().getRefNum() == mRefNumToFind)
+            {
+                mFound = ptr.getBase();
+                return false;
+            }
+            return true;
+        }
+    };
+
     void CellStore::writeReferences (ESM::ESMWriter& writer) const
     {
         writeReferenceCollection<ESM::ObjectState> (writer, mActivators);
@@ -647,11 +669,8 @@ namespace MWWorld
         }
     }
 
-    void CellStore::readReferences (ESM::ESMReader& reader,
-        const std::map<int, int>& contentFileMap)
+    void CellStore::readReferences (ESM::ESMReader& reader, const std::map<int, int>& contentFileMap, GetCellStoreCallback* callback)
     {
-        // TODO: read moved references
-
         mHasState = true;
 
         while (reader.isNextSub ("OBJE"))
@@ -787,7 +806,35 @@ namespace MWWorld
             refnum.load(reader, true, "MVRF");
             movedTo.load(reader);
 
-            std::cout << "moved to " << movedTo.mWorldspace << " " << movedTo.mIndex.mX << " " << movedTo.mIndex.mY << std::endl;
+            // Search for the reference. It might no longer exist if its content file was removed.
+            SearchByRefNumVisitor visitor(refnum);
+            forEachInternal(visitor);
+
+            if (!visitor.mFound)
+            {
+                std::cout << "Dropping moved ref tag for " << visitor.mFound->mRef.getRefId() << " (moved object no longer exists)" << std::endl;
+                continue;
+            }
+
+            CellStore* otherCell = callback->getCellStore(movedTo);
+
+            if (otherCell == NULL)
+            {
+                std::cerr << "Dropping moved ref tag for " << visitor.mFound->mRef.getRefId()
+                          << " (target cell " << movedTo.mWorldspace << " no longer exists). Reference moved back to its original location." << std::endl;
+                // Note by dropping tag the object will automatically re-appear in its original cell, though potentially at inapproriate coordinates.
+                // Restore original coordinates:
+                visitor.mFound->mData.setPosition(visitor.mFound->mRef.getPosition());
+                continue;
+            }
+
+            if (otherCell == this)
+            {
+                std::cerr << "Found invalid moved ref, ignoring" << std::endl;
+                continue;
+            }
+
+            moveTo(MWWorld::Ptr(visitor.mFound, this), otherCell);
         }
 
         updateMergedRefs();

apps/openmw/mwworld/cellstore.hpp

@@ -12,8 +12,6 @@
 #include "livecellref.hpp"
 #include "cellreflist.hpp"
 
-#include <components/esm/cellid.hpp>
-
 #include <components/esm/loadacti.hpp>
 #include <components/esm/loadalch.hpp>
 #include <components/esm/loadappa.hpp>
@@ -42,6 +40,7 @@ namespace ESM
 {
     struct CellState;
     struct FogState;
+    struct CellId;
 }
 
 namespace MWWorld
@@ -263,7 +262,15 @@ namespace MWWorld
 
             void writeReferences (ESM::ESMWriter& writer) const;
 
-            void readReferences (ESM::ESMReader& reader, const std::map<int, int>& contentFileMap);
+            struct GetCellStoreCallback
+            {
+            public:
+                ///@note must return NULL if the cell is not found
+                virtual CellStore* getCellStore(const ESM::CellId& cellId) = 0;
+            };
+
+            /// @param callback to use for retrieving of additional CellStore objects by ID (required for resolving moved references)
+            void readReferences (ESM::ESMReader& reader, const std::map<int, int>& contentFileMap, GetCellStoreCallback* callback);
 
             void respawn ();
             ///< Check mLastRespawn and respawn references if necessary. This is a no-op if the cell is not loaded.