Fix binary asset dependencies tracking when dependent asset gets loaded later on

#3951

Adds additional cache for dependencies tracking to update them when other asset gets loaded later on.
Remove critical-section from `LoadAssetTask` that was causing some deadlocks (data access is already atomic there).

Source/Engine/Content/BinaryAsset.cpp

@@ -84,6 +84,11 @@ bool BinaryAsset::Init(AssetInitData& initData)
         {
             asset->_dependantAssets.Add(this);
         }
+        else
+        {
+            // Dependency is not yet loaded to keep track this link to act when it's loaded
+            Content::onAssetDepend(this, e.First);
+        }
     }
 #endif
 

Source/Engine/Content/BinaryAsset.h

@@ -22,6 +22,7 @@
 API_CLASS(Abstract, NoSpawn) class FLAXENGINE_API BinaryAsset : public Asset
 {
     DECLARE_ASSET_HEADER(BinaryAsset);
+    friend Content;
 protected:
     AssetHeader _header;
     FlaxStorageReference _storageRef; // Allow asset to have missing storage reference but only before asset is loaded or if it's virtual

Source/Engine/Content/Content.cpp

@@ -94,6 +94,9 @@ namespace
     DateTime LastWorkspaceDiscovery;
     CriticalSection WorkspaceDiscoveryLocker;
 #endif
+#if USE_EDITOR
+    Dictionary<Guid, HashSet<BinaryAsset*>> PendingDependencies;
+#endif
 }
 
 #if ENABLE_ASSETS_DISCOVERY
@@ -157,6 +160,9 @@ void ContentService::Update()
     {
         auto asset = LoadedAssetsToInvoke.Dequeue();
         asset->onLoaded_MainThread();
+#if USE_EDITOR
+        Content::onAddDependencies(asset);
+#endif
     }
 }
 
@@ -1027,10 +1033,17 @@ bool Content::CloneAssetFile(const StringView& dstPath, const StringView& srcPat
             FileSystem::DeleteFile(tmpPath);
 
             // Reload storage
-            if (auto storage = ContentStorageManager::GetStorage(dstPath, false))
+            auto storage = ContentStorageManager::GetStorage(dstPath, false);
+            if (storage && storage->IsLoaded())
             {
                 storage->Reload();
             }
+            else if (auto dependencies = PendingDependencies.TryGet(dstId))
+            {
+                // Destination storage is not loaded but there are other assets that depend on it so update them
+                for (const auto& e : *dependencies)
+                    e.Item->OnDependencyModified(nullptr);
+            }
         }
     }
     else
@@ -1218,6 +1231,9 @@ void Content::tryCallOnLoaded(Asset* asset)
     {
         LoadedAssetsToInvoke.RemoveAtKeepOrder(index);
         asset->onLoaded_MainThread();
+#if USE_EDITOR
+        onAddDependencies(asset);
+#endif
     }
 }
 
@@ -1235,6 +1251,10 @@ void Content::onAssetUnload(Asset* asset)
     Assets.Remove(asset->GetID());
     UnloadQueue.Remove(asset);
     LoadedAssetsToInvoke.Remove(asset);
+#if USE_EDITOR
+    for (auto& e : PendingDependencies)
+        e.Value.Remove(asset);
+#endif
 }
 
 void Content::onAssetChangeId(Asset* asset, const Guid& oldId, const Guid& newId)
@@ -1242,8 +1262,42 @@ void Content::onAssetChangeId(Asset* asset, const Guid& oldId, const Guid& newId
     ScopeLock locker(AssetsLocker);
     Assets.Remove(oldId);
     Assets.Add(newId, asset);
+#if USE_EDITOR
+    if (PendingDependencies.ContainsKey(oldId))
+    {
+        auto deps = MoveTemp(PendingDependencies[oldId]);
+        PendingDependencies.Remove(oldId);
+        PendingDependencies.Add(newId, MoveTemp(deps));
+    }
+#endif
 }
 
+#if USE_EDITOR
+
+void Content::onAssetDepend(BinaryAsset* asset, const Guid& otherId)
+{
+    ScopeLock locker(AssetsLocker);
+    PendingDependencies[otherId].Add(asset);
+}
+
+void Content::onAddDependencies(Asset* asset)
+{
+    auto it = PendingDependencies.Find(asset->GetID());
+    if (it.IsNotEnd())
+    {
+        auto& dependencies = it->Value;
+        auto binaryAsset = Asset::Cast<BinaryAsset>(asset);
+        if (binaryAsset)
+        {
+            for (const auto& e : dependencies)
+                binaryAsset->_dependantAssets.Add(e.Item);
+        }
+        PendingDependencies.Remove(it);
+    }
+}
+
+#endif
+
 bool Content::IsAssetTypeIdInvalid(const ScriptingTypeHandle& type, const ScriptingTypeHandle& assetType)
 {
     // Skip if no restrictions for the type

Source/Engine/Content/Content.h

@@ -389,6 +389,12 @@ private:
     static void onAssetLoaded(Asset* asset);
     static void onAssetUnload(Asset* asset);
     static void onAssetChangeId(Asset* asset, const Guid& oldId, const Guid& newId);
+#if USE_EDITOR
+    friend class BinaryAsset;
+    friend class ContentService;
+    static void onAssetDepend(BinaryAsset* asset, const Guid& otherId);
+    static void onAddDependencies(Asset* asset);
+#endif
     static void deleteFileSafety(const StringView& path, const Guid& id);
 
     // Internal bindings

Source/Engine/Content/Loading/Tasks/LoadAssetTask.h

@@ -80,7 +80,6 @@ private:
         auto asset = Asset.Get();
         if (asset)
         {
-            asset->Locker.Lock();
             Task* task = (Task*)Platform::AtomicRead(&asset->_loadingTask);
             if (task)
             {
@@ -99,7 +98,6 @@ private:
                     task = task->GetContinueWithTask();
                 } while (task);
             }
-            asset->Locker.Unlock();
         }
     }
 };