Fix crash when closing handles to asset file while any asset streaming task is active for asset from that file

Source/Engine/Content/Asset.cpp

@@ -481,6 +481,10 @@ void Asset::InitAsVirtual()
     _isLoaded = true;
 }
 
+void Asset::CancelStreaming()
+{
+}
+
 #if USE_EDITOR
 
 void Asset::GetReferences(Array<Guid>& output) const

Source/Engine/Content/Asset.h

@@ -154,6 +154,11 @@ public:
     /// </summary>
     virtual void InitAsVirtual();
 
+    /// <summary>
+    /// Cancels any asynchronous content streaming by this asset (eg. mesh data streaming into GPU memory). Will release any locks for asset storage container.
+    /// </summary>
+    virtual void CancelStreaming();
+
 #if USE_EDITOR
 
     /// <summary>

Source/Engine/Content/Assets/Model.cpp

@@ -769,6 +769,11 @@ void Model::InitAsVirtual()
     BinaryAsset::InitAsVirtual();
 }
 
+void Model::CancelStreaming()
+{
+    CancelStreamingTasks();
+}
+
 #if USE_EDITOR
 
 void Model::GetReferences(Array<Guid>& output) const
@@ -849,6 +854,15 @@ Task* Model::CreateStreamingTask(int32 residency)
     return result;
 }
 
+void Model::CancelStreamingTasks()
+{
+    if (_streamingTask)
+    {
+        _streamingTask->Cancel();
+        ASSERT_LOW_LAYER(_streamingTask == nullptr);
+    }
+}
+
 Asset::LoadResult Model::load()
 {
     // Get header chunk

Source/Engine/Content/Assets/Model.h

@@ -251,6 +251,7 @@ public:
     int32 GetLODsCount() const override;
     void GetMeshes(Array<MeshBase*>& meshes, int32 lodIndex = 0) override;
     void InitAsVirtual() override;
+    void CancelStreaming() override;
 #if USE_EDITOR
     void GetReferences(Array<Guid>& output) const override;
 #endif
@@ -262,6 +263,7 @@ public:
     bool CanBeUpdated() const override;
     Task* UpdateAllocation(int32 residency) override;
     Task* CreateStreamingTask(int32 residency) override;
+    void CancelStreamingTasks() override;
 
 protected:
     // [ModelBase]

Source/Engine/Content/Assets/SkinnedModel.cpp

@@ -760,6 +760,11 @@ void SkinnedModel::InitAsVirtual()
     BinaryAsset::InitAsVirtual();
 }
 
+void SkinnedModel::CancelStreaming()
+{
+    CancelStreamingTasks();
+}
+
 #if USE_EDITOR
 
 void SkinnedModel::GetReferences(Array<Guid>& output) const
@@ -840,6 +845,15 @@ Task* SkinnedModel::CreateStreamingTask(int32 residency)
     return result;
 }
 
+void SkinnedModel::CancelStreamingTasks()
+{
+    if (_streamingTask)
+    {
+        _streamingTask->Cancel();
+        ASSERT_LOW_LAYER(_streamingTask == nullptr);
+    }
+}
+
 Asset::LoadResult SkinnedModel::load()
 {
     // Get header chunk

Source/Engine/Content/Assets/SkinnedModel.h

@@ -273,6 +273,7 @@ public:
     int32 GetLODsCount() const override;
     void GetMeshes(Array<MeshBase*>& meshes, int32 lodIndex = 0) override;
     void InitAsVirtual() override;
+    void CancelStreaming() override;
 #if USE_EDITOR
     void GetReferences(Array<Guid>& output) const override;
 #endif
@@ -284,6 +285,7 @@ public:
     bool CanBeUpdated() const override;
     Task* UpdateAllocation(int32 residency) override;
     Task* CreateStreamingTask(int32 residency) override;
+    void CancelStreamingTasks() override;
 
 protected:
     // [ModelBase]

Source/Engine/Content/Storage/FlaxStorage.cpp

@@ -9,6 +9,8 @@
 #include "Engine/Platform/File.h"
 #include "Engine/Profiler/ProfilerCPU.h"
 #include "Engine/Serialization/FileWriteStream.h"
+#include "Engine/Content/Asset.h"
+#include "Engine/Content/Content.h"
 #include "Engine/Threading/Threading.h"
 #if USE_EDITOR
 #include "Engine/Serialization/JsonWriter.h"
@@ -1289,9 +1291,24 @@ void FlaxStorage::CloseFileHandles()
     // In those situations all the async tasks using this storage should be cancelled externally
 
     // Ensure that no one is using this resource
-    int32 waitTime = 500;
+    int32 waitTime = 10;
     while (Platform::AtomicRead(&_chunksLock) != 0 && waitTime-- > 0)
         Platform::Sleep(10);
+    if (Platform::AtomicRead(&_chunksLock) != 0)
+    {
+        // File can be locked by some streaming tasks (eg. AudioClip::StreamingTask or StreamModelLODTask)
+        for (int32 i = 0; i < GetEntriesCount(); i++)
+        {
+            Entry e;
+            GetEntry(i, e);
+            Asset* asset = Content::GetAsset(e.ID);
+            if (asset)
+            {
+                LOG(Info, "Canceling streaming for asset {0}", asset->ToString());
+                asset->CancelStreaming();
+            }
+        }
+    }
     ASSERT(_chunksLock == 0);
 
     _file.DeleteAll();