1 /* Copyright 2020 The TensorFlow Authors. All Rights Reserved.
2 
3 Licensed under the Apache License, Version 2.0 (the "License");
4 you may not use this file except in compliance with the License.
5 You may obtain a copy of the License at
6 
7     http://www.apache.org/licenses/LICENSE-2.0
8 
9 Unless required by applicable law or agreed to in writing, software
10 distributed under the License is distributed on an "AS IS" BASIS,
11 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 See the License for the specific language governing permissions and
13 limitations under the License.
14 ==============================================================================*/
15 
16 #ifndef TENSORFLOW_C_EXPERIMENTAL_SAVED_MODEL_CORE_CONCRETE_FUNCTION_H_
17 #define TENSORFLOW_C_EXPERIMENTAL_SAVED_MODEL_CORE_CONCRETE_FUNCTION_H_
18 
19 #include <memory>
20 #include <vector>
21 
22 #include "absl/types/span.h"
23 #include "tensorflow/c/eager/immediate_execution_operation.h"
24 #include "tensorflow/c/eager/immediate_execution_tensor_handle.h"
25 #include "tensorflow/c/experimental/saved_model/core/function_metadata.h"
26 
27 namespace tensorflow {
28 
29 // ConcreteFunctions correspond to an instance of a tf.function with a known set
30 // of inputs (either through get_concrete_function) or an input_signature.
31 // ConcreteFunction attempts to preserve the user-facing semantics of the
32 // tf.function python API and can take a limited set of types as arguments
33 // (to be modeled in tensorflow::Value), not just Tensors.
34 // SavedModelAPI's ConcreteFunctions' lifetimes are bound to the SavedModel they
35 // are loaded from, since they retain pointers to the TensorHandles owned by the
36 // SavedModel, and the FunctionDef of the SavedModel.
37 // Note(bmzhao): This class is only TEMPORARILY virtual, as a way to unblock
38 // TFRT integration with TF Serving. Do not add more virtual implementations of
39 // this class. Eventually we want to remove this virtual base class indirection
40 // and have only a single implementation.
41 class ConcreteFunction {
42  public:
43   virtual ~ConcreteFunction() = default;
44 
45   // This method returns the "Call" Op used to execute the function.
46   virtual Status MakeCallOp(absl::Span<AbstractTensorHandle* const> inputs,
47                             ImmediateOpPtr* out) const = 0;
48 
49   virtual const FunctionMetadata& GetFunctionMetadata() const = 0;
50 };
51 
52 }  // namespace tensorflow
53 
54 #endif  // TENSORFLOW_C_EXPERIMENTAL_SAVED_MODEL_CORE_CONCRETE_FUNCTION_H_
55