[MachineLearning.Train] Change internal logic to resolve a memory leak

There were issues with heap use after free and heap overflow occurring
(TNINE-4152, 4153, 4154).

In order to solve this problem, modified the internal logic of the API.

Signed-off-by: SeoHyungjun <hyungjun.seo@samsung.com>

src/Tizen.MachineLearning.Train/Tizen.MachineLearning.Train/Dataset.cs

@@ -37,13 +37,19 @@ public class Dataset: IDisposable
  private IntPtr handle = IntPtr.Zero;
  private bool disposed = false;
 
+ /// if false, model will be destroy dataset handle
+ private bool hasOwnership = true;
+
  /// <summary>
  /// Constructs the dataset.
  /// </summary>
  /// <since_tizen> 10 </since_tizen>
  public Dataset()
  {
  NNTrainerError ret = Interop.Dataset.Create(out handle);
+ if (ret != NNTrainerError.None) {
+ handle = IntPtr.Zero;
+ }
  NNTrainer.CheckException(ret, "Failed to create dataset instance");
  Log.Info(NNTrainer.Tag, "Create Dataset");
  }
@@ -82,6 +88,14 @@ protected virtual void Dispose(bool disposing)
  {
  // release managed object
  }
+
+ disposed = true;
+
+ if (!hasOwnership){
+ Log.Info(NNTrainer.Tag, "Cannot destroy dataset already added in a Model. Model will destroy this dataset");
+ return;
+ }
+
  // release unmanaged object
  if (handle != IntPtr.Zero)
  {
@@ -92,7 +106,6 @@ protected virtual void Dispose(bool disposing)
 
  handle = IntPtr.Zero;
  }
- disposed = true;
  }
 
  /// <summary>
@@ -124,6 +137,11 @@ internal IntPtr GetHandle()
  return handle;
  }
 
+ internal void RemoveOwnership()
+ {
+ this.hasOwnership = false;
+ }
+
  /// <summary>
  /// Sets the neural network dataset property.
  /// </summary>

src/Tizen.MachineLearning.Train/Tizen.MachineLearning.Train/Layer.cs

@@ -49,6 +49,9 @@ public class Layer: IDisposable
  public Layer(NNTrainerLayerType type)
  {
  NNTrainerError ret = Interop.Layer.Create(out handle, type);
+ if (ret != NNTrainerError.None) {
+ handle = IntPtr.Zero;
+ }
  NNTrainer.CheckException(ret, "Failed to create model instance");
  Log.Info(NNTrainer.Tag, $"Create layer with type:{type}");
  }
@@ -98,7 +101,7 @@ protected virtual void Dispose(bool disposing)
  disposed = true;
 
  if (!hasOwnership){
- Log.Error(NNTrainer.Tag, "Cannot destroy layer already added in a Model. Model will destroy this layer");
+ Log.Info(NNTrainer.Tag, "Cannot destroy layer already added in a Model. Model will destroy this layer");
  return;
  }
 

src/Tizen.MachineLearning.Train/Tizen.MachineLearning.Train/Model.cs

@@ -65,6 +65,9 @@ public Model(string modelConf)
  NNTrainer.CheckException(NNTrainerError.InvalidParameter, "modelConf is null");
 
  NNTrainerError ret = Interop.Model.ConstructWithConf(modelConf, out handle);
+ if (ret != NNTrainerError.None) {
+ handle = IntPtr.Zero;
+ }
  NNTrainer.CheckException(ret, "Failed to create model instance with modelConf");
  Log.Info(NNTrainer.Tag, "Created Model with Conf path: "+ modelConf);
  }
@@ -281,7 +284,7 @@ public void AddLayer(Layer layer)
  public Layer GetLayer(string layerName)
  {
  IntPtr layerHandle = IntPtr.Zero;
-  if (string.IsNullOrEmpty(layerName))
+ if (string.IsNullOrEmpty(layerName))
  NNTrainer.CheckException(NNTrainerError.InvalidParameter, "layerName is null");
 
  NNTrainerError ret = Interop.Model.GetLayer(handle, layerName, out layerHandle);
@@ -311,6 +314,7 @@ public void SetOptimizer(Optimizer optimizer)
 
  NNTrainerError ret = Interop.Model.SetOptimizer(handle, optimizer.GetHandle());
  NNTrainer.CheckException(ret, "Failed to set optimizer");
+ optimizer.RemoveOwnership();
  }
 
  /// <summary>
@@ -335,6 +339,7 @@ public void SetDataset(Dataset dataset)
 
  NNTrainerError ret = Interop.Model.SetDataset(handle, dataset.GetHandle());
  NNTrainer.CheckException(ret, "Failed to set dataset");
+ dataset.RemoveOwnership();
  }
 
  internal static TensorsInfo CreateTensorsInfoFormHandle(IntPtr handle)

src/Tizen.MachineLearning.Train/Tizen.MachineLearning.Train/Optimizer.cs

@@ -37,6 +37,9 @@ public class Optimizer: IDisposable
  private IntPtr handle = IntPtr.Zero;
  private bool disposed = false;
 
+ /// if false, model will be destroy optimizer handle
+ private bool hasOwnership = true;
+
  /// <summary>
  /// Creates a neural network optimizer.
  /// </summary>
@@ -45,6 +48,9 @@ public class Optimizer: IDisposable
  public Optimizer(NNTrainerOptimizerType type)
  {
  NNTrainerError ret = Interop.Optimizer.Create(out handle, type);
+ if (ret != NNTrainerError.None) {
+ handle = IntPtr.Zero;
+ }
  NNTrainer.CheckException(ret, "Failed to create optimizer instance");
  Log.Info(NNTrainer.Tag, $"Create optimizer with type:{type}");
  }
@@ -83,6 +89,14 @@ protected virtual void Dispose(bool disposing)
  {
  // release managed object
  }
+
+ disposed = true;
+
+ if (!hasOwnership){
+ Log.Info(NNTrainer.Tag, "Cannot destroy optimizer already added in a Model. Model will destroy this optimizer");
+ return;
+ }
+
  // release unmanaged object
  if (handle != IntPtr.Zero)
  {
@@ -93,7 +107,6 @@ protected virtual void Dispose(bool disposing)
 
  handle = IntPtr.Zero;
  }
- disposed = true;
  }
 
  /// <summary>
@@ -122,5 +135,10 @@ internal IntPtr GetHandle()
  {
  return handle;
  }
+
+ internal void RemoveOwnership()
+ {
+ this.hasOwnership = false;
+ }
  } 
 }