Initialize Tensor with native TensorPtr.

Differential Revision: D71901449

Pull Request resolved: #9646

Author: shoumikhin

extension/apple/ExecuTorch/Exported/ExecuTorchTensor.h

@@ -61,10 +61,32 @@ typedef NS_ENUM(uint8_t, ExecuTorchShapeDynamism) {
   ExecuTorchShapeDynamismDynamicUnbound,
 } NS_SWIFT_NAME(ShapeDynamism);
 
+/**
+ * A tensor class for ExecuTorch operations.
+ *
+ * This class encapsulates a native TensorPtr instance and provides a variety of
+ * initializers and utility methods to work with tensor data.
+ */
 NS_SWIFT_NAME(Tensor)
 __attribute__((deprecated("This API is experimental.")))
 @interface ExecuTorchTensor : NSObject
 
+/**
+ * Pointer to the underlying native TensorPtr instance.
+ *
+ * @return A raw pointer to the native TensorPtr held by this Tensor class.
+ */
+@property(nonatomic, readonly) void *nativeInstance NS_SWIFT_UNAVAILABLE("");
+
+/**
+ * Initializes a tensor with a native TensorPtr instance.
+ *
+ * @param nativeInstance A pointer to a native TensorPtr instance.
+ * @return An initialized ExecuTorchTensor instance.
+ */
+- (instancetype)initWithNativeInstance:(void *)nativeInstance
+    NS_DESIGNATED_INITIALIZER NS_SWIFT_UNAVAILABLE("");
+
 + (instancetype)new NS_UNAVAILABLE;
 - (instancetype)init NS_UNAVAILABLE;
 

extension/apple/ExecuTorch/Exported/ExecuTorchTensor.mm

@@ -12,8 +12,23 @@
 
 #import <executorch/extension/tensor/tensor.h>
 
+using namespace executorch::extension;
+
 @implementation ExecuTorchTensor {
-  ::executorch::extension::TensorPtr _tensor;
+  TensorPtr _tensor;
+}
+
+- (instancetype)initWithNativeInstance:(void *)nativeInstance {
+  ET_CHECK(nativeInstance);
+  if (self = [super init]) {
+    _tensor = std::move(*reinterpret_cast<TensorPtr *>(nativeInstance));
+    ET_CHECK(_tensor);
+  }
+  return self;
+}
+
+- (void *)nativeInstance {
+  return &_tensor;
 }
 
 @end