Initial checkin of C++ header-only TensorHandle as part of RFC https://github.com/tensorflow/community/pull/207.

PiperOrigin-RevId: 311179503
Change-Id: Ib3cfb2547150d09ee655db6ca6bc72ef3ef7adde

tensorflow/c/eager/c_api.cc

@@ -924,7 +924,7 @@ extern TFE_ContextDevicePlacementPolicy TFE_ContextGetDevicePlacementPolicy(
       context->GetDevicePlacementPolicy());
 }
 
-TFE_TensorHandle* TFE_NewTensorHandle(TF_Tensor* t, TF_Status* status) {
+TFE_TensorHandle* TFE_NewTensorHandle(const TF_Tensor* t, TF_Status* status) {
   tensorflow::Tensor tensor;
   status->status = tensorflow::TF_TensorToTensor(t, &tensor);
   if (!status->status.ok()) return nullptr;

tensorflow/c/eager/c_api.h

@@ -137,7 +137,7 @@ TF_CAPI_EXPORT extern void TFE_ContextSetServerDef(TFE_Context* ctx,
 // placed in memory of different devices or remote address spaces.
 typedef struct TFE_TensorHandle TFE_TensorHandle;
 
-TF_CAPI_EXPORT extern TFE_TensorHandle* TFE_NewTensorHandle(TF_Tensor* t,
+TF_CAPI_EXPORT extern TFE_TensorHandle* TFE_NewTensorHandle(const TF_Tensor* t,
                                                             TF_Status* status);
 // Indicates that the caller will not be using `h` any more.
 TF_CAPI_EXPORT extern void TFE_DeleteTensorHandle(TFE_TensorHandle* h);

tensorflow/cc/experimental/base/public/BUILD

@@ -62,3 +62,17 @@ cc_library(
         "//tensorflow/c:tf_tensor",
     ],
 )
+
+cc_library(
+    name = "tensorhandle",
+    hdrs = [
+        "tensorhandle.h",
+    ],
+    deps = [
+        ":runtime",
+        ":status",
+        ":tensor",
+        "//tensorflow/c/eager:c_api",
+        "//tensorflow/c/eager:c_api_experimental",
+    ],
+)

tensorflow/cc/experimental/base/public/runtime.h

@@ -21,6 +21,7 @@ limitations under the License.
 #include "tensorflow/c/eager/c_api_experimental.h"
 
 namespace tensorflow {
+namespace experimental {
 namespace cc {
 
 // Runtime represents an opaque instance of a Tensorflow runtime, with its own
@@ -40,6 +41,7 @@ class Runtime {
  private:
   friend class RuntimeBuilder;
   friend class SavedModelAPI;
+  friend class TensorHandle;
 
   // Wraps a TFE_Context. Takes ownership of ctx.
   explicit Runtime(TFE_Context* ctx) : ctx_(ctx) {}
@@ -63,6 +65,7 @@ class Runtime {
 };
 
 }  // namespace cc
+}  // namespace experimental
 }  // namespace tensorflow
 
 #endif  // TENSORFLOW_CC_EXPERIMENTAL_BASE_PUBLIC_RUNTIME_H_

tensorflow/cc/experimental/base/public/runtime_builder.h

@@ -24,6 +24,7 @@ limitations under the License.
 #include "tensorflow/cc/experimental/base/public/status.h"
 
 namespace tensorflow {
+namespace experimental {
 namespace cc {
 
 // RuntimeBuilder is a builder used to construct a tensorflow::cc::Runtime.
@@ -79,6 +80,7 @@ inline std::unique_ptr<Runtime> RuntimeBuilder::Build(Status* status) {
 }
 
 }  // namespace cc
+}  // namespace experimental
 }  // namespace tensorflow
 
 #endif  // TENSORFLOW_CC_EXPERIMENTAL_BASE_PUBLIC_RUNTIME_BUILDER_H_

tensorflow/cc/experimental/base/public/status.h

@@ -22,6 +22,7 @@ limitations under the License.
 #include "tensorflow/c/tf_status.h"
 
 namespace tensorflow {
+namespace experimental {
 namespace cc {
 
 // Status is a wrapper around an error code and an optional error message.
@@ -57,6 +58,7 @@ class Status {
   friend class RuntimeBuilder;
   friend class Runtime;
   friend class SavedModelAPI;
+  friend class TensorHandle;
 
   // Wraps a TF_Status*, and takes ownership of it.
   explicit Status(TF_Status* status) : status_(status) {}
@@ -88,6 +90,7 @@ inline void Status::SetStatus(TF_Code code, const std::string& msg) {
 }
 
 }  // namespace cc
+}  // namespace experimental
 }  // namespace tensorflow
 
 #endif  // TENSORFLOW_CC_EXPERIMENTAL_BASE_PUBLIC_STATUS_H_

tensorflow/cc/experimental/base/public/tensor.h

@@ -28,6 +28,7 @@ limitations under the License.
 #include "tensorflow/cc/experimental/base/public/status.h"
 
 namespace tensorflow {
+namespace experimental {
 namespace cc {
 
 // Tensor represents an n-dimensional array of values.
@@ -168,6 +169,7 @@ inline Tensor Tensor::FromBuffer(TF_DataType dtype,
 }
 
 }  // namespace cc
+}  // namespace experimental
 }  // namespace tensorflow
 
 #endif  // TENSORFLOW_CC_EXPERIMENTAL_BASE_PUBLIC_TENSOR_H_

tensorflow/cc/experimental/base/public/tensorhandle.h

@@ -0,0 +1,98 @@
+/* Copyright 2020 The TensorFlow Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+==============================================================================*/
+
+#ifndef TENSORFLOW_CC_EXPERIMENTAL_BASE_PUBLIC_TENSORHANDLE_H_
+#define TENSORFLOW_CC_EXPERIMENTAL_BASE_PUBLIC_TENSORHANDLE_H_
+
+#include <memory>
+#include <vector>
+
+#include "tensorflow/c/eager/c_api.h"
+#include "tensorflow/c/eager/c_api_experimental.h"
+#include "tensorflow/cc/experimental/base/public/runtime.h"
+#include "tensorflow/cc/experimental/base/public/status.h"
+#include "tensorflow/cc/experimental/base/public/tensor.h"
+
+namespace tensorflow {
+namespace experimental {
+namespace cc {
+
+// An opaque representation of a tensor computed/managed by the Tensorflow
+// runtime (tensorflow:cc::Runtime). Unlike a tensor, a Tensorhandle may refer
+// to tensors placed in memory of different devices or remote address spaces.
+// Note that tensorflow::cc::Runtime MUST outlive all TensorHandles created
+// from it.
+class TensorHandle {
+ public:
+  // Unwraps a Tensor from the given TensorHandle. If an error occurred,
+  // status->ok() will be false, and the returned Tensor must not be used.
+  Tensor Resolve(Status* status);
+
+  // Constructs a TensorHandle from a Tensor. If an error occurred,
+  // status->ok() will be false, and the returned TensorHandle must not be used.
+  static TensorHandle FromTensor(const Tensor& tensor, const Runtime& runtime,
+                                 Status* status);
+
+  // TensorHandle is movable, and not copyable
+  TensorHandle(TensorHandle&&) = default;
+  TensorHandle& operator=(TensorHandle&&) = default;
+
+ private:
+  // Wraps a TFE_TensorHandle. Takes ownership of handle.
+  explicit TensorHandle(TFE_TensorHandle* handle) : handle_(handle) {}
+
+  // TensorHandle is not copyable
+  TensorHandle(const TensorHandle&) = delete;
+  TensorHandle& operator=(const TensorHandle&) = delete;
+
+  // Returns the underlying TFE_TensorHandle that this object wraps.
+  // This object retains ownership of the pointer.
+  TFE_TensorHandle* GetTFETensorHandle() const { return handle_.get(); }
+
+  // Deletes the currently wrapped TFE_TensorHandle, and swaps it with handle,
+  // and takes ownership of handle.
+  void Reset(TFE_TensorHandle* handle) { handle_.reset(handle); }
+
+  struct TFETensorHandleDeleter {
+    void operator()(TFE_TensorHandle* p) const { TFE_DeleteTensorHandle(p); }
+  };
+  std::unique_ptr<TFE_TensorHandle, TFETensorHandleDeleter> handle_;
+};
+
+inline Tensor TensorHandle::Resolve(Status* status) {
+  TF_Tensor* tensor =
+      TFE_TensorHandleResolve(handle_.get(), status->GetTFStatus());
+  if (!status->ok()) {
+    return Tensor(nullptr);
+  }
+  return Tensor(tensor);
+}
+
+inline TensorHandle TensorHandle::FromTensor(const Tensor& tensor,
+                                             const Runtime& runtime,
+                                             Status* status) {
+  TFE_TensorHandle* tensor_handle = TFE_NewTensorHandleFromTensor(
+      runtime.GetTFEContext(), tensor.GetTFTensor(), status->GetTFStatus());
+  if (!status->ok()) {
+    return TensorHandle(nullptr);
+  }
+  return TensorHandle(tensor_handle);
+}
+
+}  // namespace cc
+}  // namespace experimental
+}  // namespace tensorflow
+
+#endif  // TENSORFLOW_CC_EXPERIMENTAL_BASE_PUBLIC_TENSORHANDLE_H_

tensorflow/cc/experimental/base/tests/BUILD

@@ -5,12 +5,22 @@ package(
     licenses = ["notice"],  # Apache 2.0
 )
 
+cc_library(
+    name = "tensor_types_test_util",
+    testonly = True,
+    hdrs = ["tensor_types_test_util.h"],
+    deps = [
+        "//tensorflow/c:tf_datatype",
+    ],
+)
+
 tf_cc_test(
     name = "tensor_test",
     srcs = [
         "tensor_test.cc",
     ],
     deps = [
+        ":tensor_types_test_util",
         "//tensorflow/c:tf_datatype",
         "//tensorflow/cc/experimental/base/public:status",
         "//tensorflow/cc/experimental/base/public:tensor",
@@ -19,3 +29,22 @@ tf_cc_test(
         "//tensorflow/core:test_main",
     ],
 )
+
+tf_cc_test(
+    name = "tensorhandle_test",
+    srcs = [
+        "tensorhandle_test.cc",
+    ],
+    deps = [
+        ":tensor_types_test_util",
+        "//tensorflow/c:tf_datatype",
+        "//tensorflow/cc/experimental/base/public:runtime",
+        "//tensorflow/cc/experimental/base/public:runtime_builder",
+        "//tensorflow/cc/experimental/base/public:status",
+        "//tensorflow/cc/experimental/base/public:tensor",
+        "//tensorflow/cc/experimental/base/public:tensorhandle",
+        "//tensorflow/core:lib",
+        "//tensorflow/core:test",
+        "//tensorflow/core:test_main",
+    ],
+)

tensorflow/cc/experimental/base/tests/tensor_test.cc

@@ -16,69 +16,22 @@ limitations under the License.
 #include "tensorflow/cc/experimental/base/public/tensor.h"
 
 #include <stddef.h>
-
+#include <stdint.h>
-#include <cstdint>
 
 #include "tensorflow/c/tf_datatype.h"
+#include "tensorflow/cc/experimental/base/tests/tensor_types_test_util.h"
 #include "tensorflow/core/lib/gtl/array_slice.h"
 #include "tensorflow/core/platform/test.h"
 
-namespace tensorflow {
 namespace {
 
-// Each of the following struct types have two members: a kDType that
+using tensorflow::experimental::cc::Status;
-// corresponds to a TF_Datatype enum value, and a typedef "type"
+using tensorflow::experimental::cc::Tensor;
-// of its corresponding C++ type. These types allow us to write Dtype-agnostic
-// tests via GoogleTest's TypedTests:
-// https://github.com/google/googletest/blob/e589a337170554c48bc658cc857cf15080c9eacc/googletest/docs/advanced.md#typed-tests
-struct FloatType {
-  using type = float;
-  static constexpr TF_DataType kDType = TF_FLOAT;
-};
 
-struct DoubleType {
+using SimpleTypes = ::testing::Types<
-  using type = double;
+    tensorflow::FloatType, tensorflow::DoubleType, tensorflow::Int32Type,
-  static constexpr TF_DataType kDType = TF_DOUBLE;
+    tensorflow::UINT8Type, tensorflow::INT8Type, tensorflow::INT64Type,
-};
+    tensorflow::UINT16Type, tensorflow::UINT32Type, tensorflow::UINT64Type>;
-
-struct Int32Type {
-  using type = int32_t;
-  static constexpr TF_DataType kDType = TF_INT32;
-};
-
-struct UINT8Type {
-  using type = uint8_t;
-  static constexpr TF_DataType kDType = TF_UINT8;
-};
-
-struct INT8Type {
-  using type = int8_t;
-  static constexpr TF_DataType kDType = TF_INT8;
-};
-
-struct INT64Type {
-  using type = int64_t;
-  static constexpr TF_DataType kDType = TF_INT64;
-};
-
-struct UINT16Type {
-  using type = uint16_t;
-  static constexpr TF_DataType kDType = TF_UINT16;
-};
-
-struct UINT32Type {
-  using type = uint32_t;
-  static constexpr TF_DataType kDType = TF_UINT32;
-};
-
-struct UINT64Type {
-  using type = uint64_t;
-  static constexpr TF_DataType kDType = TF_UINT64;
-};
-
-using SimpleTypes =
-    ::testing::Types<FloatType, DoubleType, Int32Type, UINT8Type, INT8Type,
-                     INT64Type, UINT16Type, UINT32Type, UINT64Type>;
 
 template <typename T>
 class ConstructScalarTensorTest : public ::testing::Test {};
@@ -88,11 +41,10 @@ TYPED_TEST_SUITE(ConstructScalarTensorTest, SimpleTypes);
 // and verifies the expected dimensions, dtype, value, number of bytes, and
 // number of elements.
 TYPED_TEST(ConstructScalarTensorTest, ValidTensorAttributesAfterConstruction) {
-  cc::Status status;
+  Status status;
   TF_DataType dtype = TypeParam::kDType;
   typename TypeParam::type value = 42;
-  cc::Tensor tensor =
+  Tensor tensor = Tensor::FromBuffer(/*dtype=*/dtype, /*shape=*/{},
-      cc::Tensor::FromBuffer(/*dtype=*/dtype, /*shape=*/{},
                                      /*data=*/&value,
                                      /*len=*/sizeof(value),
                                      /*deleter=*/[](void*, size_t) {}, &status);
@@ -113,7 +65,7 @@ TYPED_TEST_SUITE(Construct1DTensorTest, SimpleTypes);
 // and verifies the expected dimensions, dtype, value, number of bytes, and
 // number of elements.
 TYPED_TEST(Construct1DTensorTest, ValidTensorAttributesAfterConstruction) {
-  cc::Status status;
+  Status status;
   TF_DataType dtype = TypeParam::kDType;
   // This is our 1D tensor of varying dtype.
   std::vector<typename TypeParam::type> value = {42, 100, 0, 1, 4, 29};
@@ -121,7 +73,7 @@ TYPED_TEST(Construct1DTensorTest, ValidTensorAttributesAfterConstruction) {
   std::vector<int64_t> shape;
   shape.push_back(value.size());
 
-  cc::Tensor tensor = cc::Tensor::FromBuffer(
+  Tensor tensor = Tensor::FromBuffer(
       /*dtype=*/dtype, /*shape=*/shape,
       /*data=*/value.data(),
       /*len=*/value.size() * sizeof(typename TypeParam::type),
@@ -130,7 +82,7 @@ TYPED_TEST(Construct1DTensorTest, ValidTensorAttributesAfterConstruction) {
 
   EXPECT_EQ(tensor.dims(), 1);
   EXPECT_EQ(tensor.dtype(), dtype);
-  gtl::ArraySlice<typename TypeParam::type> tensor_view(
+  tensorflow::gtl::ArraySlice<typename TypeParam::type> tensor_view(
       reinterpret_cast<typename TypeParam::type*>(tensor.data()), value.size());
   EXPECT_EQ(tensor_view[0], 42);
   EXPECT_EQ(tensor_view[1], 100);
@@ -152,14 +104,14 @@ TYPED_TEST_SUITE(Construct2DTensorTest, SimpleTypes);
 // and verifies the expected dimensions, dtype, value, number of bytes, and
 // number of elements.
 TYPED_TEST(Construct2DTensorTest, ValidTensorAttributesAfterConstruction) {
-  cc::Status status;
+  Status status;
   TF_DataType dtype = TypeParam::kDType;
   // This is our 1D tensor of varying dtype.
   std::vector<typename TypeParam::type> value = {42, 100, 0, 1, 4, 29};
   // Shape is Rank 2 vector with shape 2 x 3.
   std::vector<int64_t> shape({2, 3});
 
-  cc::Tensor tensor = cc::Tensor::FromBuffer(
+  Tensor tensor = Tensor::FromBuffer(
       /*dtype=*/dtype, /*shape=*/shape,
       /*data=*/value.data(),
       /*len=*/value.size() * sizeof(typename TypeParam::type),
@@ -169,7 +121,7 @@ TYPED_TEST(Construct2DTensorTest, ValidTensorAttributesAfterConstruction) {
 
   EXPECT_EQ(tensor.dims(), 2);
   EXPECT_EQ(tensor.dtype(), dtype);
-  gtl::ArraySlice<typename TypeParam::type> tensor_view(
+  tensorflow::gtl::ArraySlice<typename TypeParam::type> tensor_view(
       reinterpret_cast<typename TypeParam::type*>(tensor.data()), value.size());
   EXPECT_EQ(tensor_view[0], 42);
   EXPECT_EQ(tensor_view[1], 100);
@@ -185,19 +137,19 @@ TYPED_TEST(Construct2DTensorTest, ValidTensorAttributesAfterConstruction) {
 
 TEST(CPPTensorAPI, ConstructTensorFromBuffer) {
   bool done = false;
-  cc::Status status;
+  Status status;
   std::vector<int32_t> data_vector({12, 14, 20, 18, 39, 42, 100});
   {
     // data_vector is a rank 1 tensor.
     std::vector<int64_t> shape;
     shape.push_back(data_vector.size());
 
-    cc::Tensor::DeleterCallback callback = [&done](void* data, size_t len) {
+    Tensor::DeleterCallback callback = [&done](void* data, size_t len) {
       done = true;
     };
 
-    cc::Tensor tensor =
+    Tensor tensor =
-        cc::Tensor::FromBuffer(/*dtype=*/TF_INT32, /*shape=*/shape,
+        Tensor::FromBuffer(/*dtype=*/TF_INT32, /*shape=*/shape,
                            /*data=*/data_vector.data(),
                            /*len=*/data_vector.size() * sizeof(int32_t),
                            /*deleter=*/callback, &status);
@@ -209,4 +161,3 @@ TEST(CPPTensorAPI, ConstructTensorFromBuffer) {
 }
 
 }  // namespace
-}  // namespace tensorflow

tensorflow/cc/experimental/base/tests/tensor_types_test_util.h

@@ -0,0 +1,76 @@
+/* Copyright 2020 The TensorFlow Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+==============================================================================*/
+#ifndef TENSORFLOW_CC_EXPERIMENTAL_BASE_TEST_TENSOR_TYPES_TEST_UTIL_H_
+#define TENSORFLOW_CC_EXPERIMENTAL_BASE_TEST_TENSOR_TYPES_TEST_UTIL_H_
+
+#include <stdint.h>
+
+#include "tensorflow/c/tf_datatype.h"
+
+namespace tensorflow {
+
+// Each of the following struct types have two members: a kDType that
+// corresponds to a TF_Datatype enum value, and a typedef "type"
+// of its corresponding C++ type. These types allow us to write Dtype-agnostic
+// tests via GoogleTest's TypedTests:
+// https://github.com/google/googletest/blob/e589a337170554c48bc658cc857cf15080c9eacc/googletest/docs/advanced.md#typed-tests
+struct FloatType {
+  using type = float;
+  static constexpr TF_DataType kDType = TF_FLOAT;
+};
+
+struct DoubleType {
+  using type = double;
+  static constexpr TF_DataType kDType = TF_DOUBLE;
+};
+
+struct Int32Type {
+  using type = int32_t;
+  static constexpr TF_DataType kDType = TF_INT32;
+};
+
+struct UINT8Type {
+  using type = uint8_t;
+  static constexpr TF_DataType kDType = TF_UINT8;
+};
+
+struct INT8Type {
+  using type = int8_t;
+  static constexpr TF_DataType kDType = TF_INT8;
+};
+
+struct INT64Type {
+  using type = int64_t;
+  static constexpr TF_DataType kDType = TF_INT64;
+};
+
+struct UINT16Type {
+  using type = uint16_t;
+  static constexpr TF_DataType kDType = TF_UINT16;
+};
+
+struct UINT32Type {
+  using type = uint32_t;
+  static constexpr TF_DataType kDType = TF_UINT32;
+};
+
+struct UINT64Type {
+  using type = uint64_t;
+  static constexpr TF_DataType kDType = TF_UINT64;
+};
+
+}  // namespace tensorflow
+
+#endif  // TENSORFLOW_CC_EXPERIMENTAL_BASE_TEST_TENSOR_TYPES_TEST_UTIL_H_

tensorflow/cc/experimental/base/tests/tensorhandle_test.cc

@@ -0,0 +1,184 @@
+/* Copyright 2020 The TensorFlow Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+==============================================================================*/
+
+#include "tensorflow/cc/experimental/base/public/tensorhandle.h"
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <memory>
+
+#include "tensorflow/c/tf_datatype.h"
+#include "tensorflow/cc/experimental/base/public/runtime.h"
+#include "tensorflow/cc/experimental/base/public/runtime_builder.h"
+#include "tensorflow/cc/experimental/base/public/tensor.h"
+#include "tensorflow/cc/experimental/base/tests/tensor_types_test_util.h"
+#include "tensorflow/core/lib/gtl/array_slice.h"
+#include "tensorflow/core/platform/test.h"
+
+namespace tensorflow {
+namespace {
+
+using tensorflow::experimental::cc::Runtime;
+using tensorflow::experimental::cc::RuntimeBuilder;
+using tensorflow::experimental::cc::Status;
+using tensorflow::experimental::cc::Tensor;
+using tensorflow::experimental::cc::TensorHandle;
+
+using SimpleTypes = ::testing::Types<
+    tensorflow::FloatType, tensorflow::DoubleType, tensorflow::Int32Type,
+    tensorflow::UINT8Type, tensorflow::INT8Type, tensorflow::INT64Type,
+    tensorflow::UINT16Type, tensorflow::UINT32Type, tensorflow::UINT64Type>;
+
+template <typename T>
+class ConstructScalarTensorHandleTest : public ::testing::Test {};
+TYPED_TEST_SUITE(ConstructScalarTensorHandleTest, SimpleTypes);
+
+// This test constructs a scalar tensor for each of the types in "SimpleTypes",
+// then wraps it in a TensorHandle. We then unwrap it back into a Tensor, and
+// verify the expected dims, dtype, value, num bytes, and num elements.
+TYPED_TEST(ConstructScalarTensorHandleTest,
+           ValidTensorAttributesAfterConstruction) {
+  Status status;
+  RuntimeBuilder runtime_builder;
+  std::unique_ptr<Runtime> runtime = runtime_builder.Build(&status);
+  ASSERT_TRUE(status.ok()) << status.message();
+
+  TF_DataType dtype = TypeParam::kDType;
+  typename TypeParam::type value = 42;
+  Tensor original_tensor =
+      Tensor::FromBuffer(/*dtype=*/dtype, /*shape=*/{},
+                         /*data=*/&value,
+                         /*len=*/sizeof(value),
+                         /*deleter=*/[](void*, size_t) {}, &status);
+  ASSERT_TRUE(status.ok()) << status.message();
+
+  TensorHandle handle =
+      TensorHandle::FromTensor(original_tensor, *runtime, &status);
+  ASSERT_TRUE(status.ok()) << status.message();
+
+  Tensor tensor = handle.Resolve(&status);
+  ASSERT_TRUE(status.ok()) << status.message();
+
+  EXPECT_EQ(tensor.dims(), 0);
+  EXPECT_EQ(tensor.dtype(), dtype);
+  EXPECT_EQ(*reinterpret_cast<typename TypeParam::type*>(tensor.data()), 42);
+  EXPECT_EQ(tensor.num_bytes(), sizeof(typename TypeParam::type));
+  EXPECT_EQ(tensor.num_elements(), 1);
+}
+
+template <typename T>
+class Construct1DTensorHandleTest : public ::testing::Test {};
+TYPED_TEST_SUITE(Construct1DTensorHandleTest, SimpleTypes);
+
+// This test constructs a 1D tensor for each of the types in "SimpleTypes",
+// and verifies the expected dimensions, dtype, value, number of bytes, and
+// number of elements.
+TYPED_TEST(Construct1DTensorHandleTest,
+           ValidTensorAttributesAfterConstruction) {
+  Status status;
+  RuntimeBuilder runtime_builder;
+  std::unique_ptr<Runtime> runtime = runtime_builder.Build(&status);
+  ASSERT_TRUE(status.ok()) << status.message();
+
+  TF_DataType dtype = TypeParam::kDType;
+  // This is our 1D tensor of varying dtype.
+  std::vector<typename TypeParam::type> value = {42, 100, 0, 1, 4, 29};
+  // Shape is Rank 1 vector.
+  std::vector<int64_t> shape;
+  shape.push_back(value.size());
+
+  Tensor original_tensor = Tensor::FromBuffer(
+      /*dtype=*/dtype, /*shape=*/shape,
+      /*data=*/value.data(),
+      /*len=*/value.size() * sizeof(typename TypeParam::type),
+      /*deleter=*/[](void*, size_t) {}, &status);
+  ASSERT_TRUE(status.ok()) << status.message();
+
+  TensorHandle handle =
+      TensorHandle::FromTensor(original_tensor, *runtime, &status);
+  ASSERT_TRUE(status.ok()) << status.message();
+
+  Tensor tensor = handle.Resolve(&status);
+  ASSERT_TRUE(status.ok()) << status.message();
+
+  EXPECT_EQ(tensor.dims(), 1);
+  EXPECT_EQ(tensor.dtype(), dtype);
+  tensorflow::gtl::ArraySlice<typename TypeParam::type> tensor_view(
+      reinterpret_cast<typename TypeParam::type*>(tensor.data()), value.size());
+  EXPECT_EQ(tensor_view[0], 42);
+  EXPECT_EQ(tensor_view[1], 100);
+  EXPECT_EQ(tensor_view[2], 0);
+  EXPECT_EQ(tensor_view[3], 1);
+  EXPECT_EQ(tensor_view[4], 4);
+  EXPECT_EQ(tensor_view[5], 29);
+
+  EXPECT_EQ(tensor.num_bytes(),
+            value.size() * sizeof(typename TypeParam::type));
+  EXPECT_EQ(tensor.num_elements(), value.size());
+}
+
+template <typename T>
+class Construct2DTensorHandleTest : public ::testing::Test {};
+TYPED_TEST_SUITE(Construct2DTensorHandleTest, SimpleTypes);
+
+// This test constructs a 2D tensor for each of the types in "SimpleTypes",
+// and verifies the expected dimensions, dtype, value, number of bytes, and
+// number of elements.
+TYPED_TEST(Construct2DTensorHandleTest,
+           ValidTensorAttributesAfterConstruction) {
+  Status status;
+  RuntimeBuilder runtime_builder;
+  std::unique_ptr<Runtime> runtime = runtime_builder.Build(&status);
+  ASSERT_TRUE(status.ok()) << status.message();
+
+  TF_DataType dtype = TypeParam::kDType;
+  // This is our 1D tensor of varying dtype.
+  std::vector<typename TypeParam::type> value = {42, 100, 0, 1, 4, 29};
+  // Shape is Rank 2 vector with shape 2 x 3.
+  std::vector<int64_t> shape({2, 3});
+
+  Tensor original_tensor = Tensor::FromBuffer(
+      /*dtype=*/dtype, /*shape=*/shape,
+      /*data=*/value.data(),
+      /*len=*/value.size() * sizeof(typename TypeParam::type),
+      /*deleter=*/[](void*, size_t) {}, &status);
+  ASSERT_TRUE(status.ok()) << status.message();
+
+  TensorHandle handle =
+      TensorHandle::FromTensor(original_tensor, *runtime, &status);
+  ASSERT_TRUE(status.ok()) << status.message();
+
+  Tensor tensor = handle.Resolve(&status);
+  ASSERT_TRUE(status.ok()) << status.message();
+
+  EXPECT_EQ(tensor.dims(), 2);
+  EXPECT_EQ(tensor.dtype(), dtype);
+  tensorflow::gtl::ArraySlice<typename TypeParam::type> tensor_view(
+      reinterpret_cast<typename TypeParam::type*>(tensor.data()), value.size());
+  EXPECT_EQ(tensor_view[0], 42);
+  EXPECT_EQ(tensor_view[1], 100);
+  EXPECT_EQ(tensor_view[2], 0);
+  EXPECT_EQ(tensor_view[3], 1);
+  EXPECT_EQ(tensor_view[4], 4);
+  EXPECT_EQ(tensor_view[5], 29);
+
+  EXPECT_EQ(tensor.num_bytes(),
+            value.size() * sizeof(typename TypeParam::type));
+  EXPECT_EQ(tensor.num_elements(), value.size());
+}
+
+}  // namespace
+}  // namespace tensorflow

tensorflow/cc/saved_model/experimental/public/concrete_function.h

@@ -24,6 +24,7 @@ limitations under the License.
 #include "tensorflow/cc/saved_model/experimental/public/function_metadata.h"
 
 namespace tensorflow {
+namespace experimental {
 namespace cc {
 
 // ConcreteFunction is an executable "function" loaded from a SavedModelAPI.
@@ -54,6 +55,7 @@ inline const FunctionMetadata* ConcreteFunction::GetFunctionMetadata() {
 }
 
 }  // namespace cc
+}  // namespace experimental
 }  // namespace tensorflow
 
 #endif  // TENSORFLOW_CC_SAVED_MODEL_EXPERIMENTAL_PUBLIC_CONCRETE_FUNCTION_H_

tensorflow/cc/saved_model/experimental/public/concrete_function_list.h

@@ -22,6 +22,7 @@ limitations under the License.
 #include "tensorflow/cc/saved_model/experimental/public/concrete_function.h"
 
 namespace tensorflow {
+namespace experimental {
 namespace cc {
 
 // ConcreteFunctionList helps convert an opaque pointer to an array of
@@ -56,6 +57,7 @@ inline std::vector<ConcreteFunction*> ConcreteFunctionList::ToVector() {
 }
 
 }  // namespace cc
+}  // namespace experimental
 }  // namespace tensorflow
 
 #endif  // TENSORFLOW_CC_SAVED_MODEL_EXPERIMENTAL_PUBLIC_CONCRETE_FUNCTION_LIST_H_

tensorflow/cc/saved_model/experimental/public/function_metadata.h

@@ -21,6 +21,7 @@ limitations under the License.
 #include "tensorflow/c/experimental/saved_model/public/function_metadata.h"
 
 namespace tensorflow {
+namespace experimental {
 namespace cc {
 
 // FunctionMetadata stores additional function information, including
@@ -40,6 +41,7 @@ class FunctionMetadata final {
 };
 
 }  // namespace cc
+}  // namespace experimental
 }  // namespace tensorflow
 
 #endif  // TENSORFLOW_CC_SAVED_MODEL_EXPERIMENTAL_PUBLIC_FUNCTION_METADATA_H_

tensorflow/cc/saved_model/experimental/public/saved_model_api.h

@@ -28,6 +28,7 @@ limitations under the License.
 #include "tensorflow/cc/saved_model/experimental/public/concrete_function_list.h"
 
 namespace tensorflow {
+namespace experimental {
 namespace cc {
 
 // SavedModelAPI offers a way to load Tensorflow Saved Models
@@ -155,6 +156,7 @@ inline std::vector<ConcreteFunction*> SavedModelAPI::ListFunctions() {
 }
 
 }  // namespace cc
+}  // namespace experimental
 }  // namespace tensorflow
 
 #endif  // TENSORFLOW_CC_SAVED_MODEL_EXPERIMENTAL_PUBLIC_SAVED_MODEL_API_H_

tensorflow/cc/saved_model/experimental/tests/saved_model_api_test.cc

@@ -26,10 +26,14 @@ limitations under the License.
 #include "tensorflow/core/platform/stringpiece.h"
 #include "tensorflow/core/platform/test.h"
 
-namespace tensorflow {
 
 namespace {
 
+using tensorflow::experimental::cc::Runtime;
+using tensorflow::experimental::cc::RuntimeBuilder;
+using tensorflow::experimental::cc::SavedModelAPI;
+using tensorflow::experimental::cc::Status;
+
 constexpr char kTestData[] = "cc/saved_model/testdata";
 
 std::string SavedModelPath(tensorflow::StringPiece saved_model_dir) {
@@ -43,21 +47,21 @@ std::string SavedModelPath(tensorflow::StringPiece saved_model_dir) {
 class CPPSavedModelAPITest : public ::testing::TestWithParam<bool> {};
 
 TEST_P(CPPSavedModelAPITest, LoadsSavedModelWithTags) {
-  cc::Status status;
+  Status status;
-  cc::RuntimeBuilder builder;
+  RuntimeBuilder builder;
   bool use_tfrt = GetParam();
   if (use_tfrt) {
     GTEST_SKIP();  // TODO(chky) : Enable this once TFRT is open sourced.
   }
 
   builder.SetUseTFRT(use_tfrt);
-  std::unique_ptr<cc::Runtime> runtime = builder.Build(&status);
+  std::unique_ptr<Runtime> runtime = builder.Build(&status);
   ASSERT_TRUE(status.ok()) << status.message();
 
   std::string model_dir = SavedModelPath("VarsAndArithmeticObjectGraph");
   std::unordered_set<std::string> tags = {"serve"};
-  std::unique_ptr<cc::SavedModelAPI> model =
+  std::unique_ptr<SavedModelAPI> model =
-      cc::SavedModelAPI::Load(model_dir, *runtime, &status, &tags);
+      SavedModelAPI::Load(model_dir, *runtime, &status, &tags);
 
   // TODO(bmzhao): Change this to expect TF_OK when loading is implemented.
   // That unblocks writing other tests that require a TF_SavedModel*,
@@ -67,20 +71,20 @@ TEST_P(CPPSavedModelAPITest, LoadsSavedModelWithTags) {
 }
 
 TEST_P(CPPSavedModelAPITest, LoadsSavedModel) {
-  cc::Status status;
+  Status status;
-  cc::RuntimeBuilder builder;
+  RuntimeBuilder builder;
   bool use_tfrt = GetParam();
   if (use_tfrt) {
     GTEST_SKIP();  // TODO(chky) : Enable this once TFRT is open sourced.
   }
 
   builder.SetUseTFRT(use_tfrt);
-  std::unique_ptr<cc::Runtime> runtime = builder.Build(&status);
+  std::unique_ptr<Runtime> runtime = builder.Build(&status);
   ASSERT_TRUE(status.ok()) << status.message();
 
   std::string model_dir = SavedModelPath("VarsAndArithmeticObjectGraph");
-  std::unique_ptr<cc::SavedModelAPI> model =
+  std::unique_ptr<SavedModelAPI> model =
-      cc::SavedModelAPI::Load(model_dir, *runtime, &status);
+      SavedModelAPI::Load(model_dir, *runtime, &status);
 
   // TODO(bmzhao): Change this to expect TF_OK when loading is implemented.
   // That unblocks writing other tests that require a TF_SavedModel*,
@@ -94,4 +98,3 @@ INSTANTIATE_TEST_SUITE_P(RuntimeAgnosticCPPSavedModelTests,
 
 }  // namespace
 
-}  // namespace tensorflow