1/* Copyright 2022 The TensorFlow Authors. All Rights Reserved.
2
3Licensed under the Apache License, Version 2.0 (the "License");
4you may not use this file except in compliance with the License.
5You may obtain a copy of the License at
6
7 http://www.apache.org/licenses/LICENSE-2.0
8
9Unless required by applicable law or agreed to in writing, software
10distributed under the License is distributed on an "AS IS" BASIS,
11WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12See the License for the specific language governing permissions and
13limitations under the License.
14==============================================================================*/
15#ifndef TENSORFLOW_CORE_KERNELS_DATA_OPTIONAL_OPS_UTIL_H_
16#define TENSORFLOW_CORE_KERNELS_DATA_OPTIONAL_OPS_UTIL_H_
17
18#include <functional>
19#include <memory>
20#include <utility>
21#include <vector>
22
23#include "tensorflow/core/framework/tensor.h"
24#include "tensorflow/core/framework/variant_tensor_data.h"
25#include "tensorflow/core/util/tensor_ops_util.h"
26
27namespace tensorflow {
28namespace data {
29
30const char kOptionalVariantTypeName[] = "tensorflow::data::Optional";
31
32// An `OptionalVariant` can represent either an "actual value" (a tuple of
33// tensors) or "none", and may be stored in a DT_VARIANT tensor.
34class OptionalVariant {
35 public:
36 // Create an `OptionalVariant` with no actual value.
37 OptionalVariant() : values_(nullptr) {}
38
39 // Create an `OptionalVariant` with the actual value given by the tuple of
40 // tensors in `values`.
41 explicit OptionalVariant(std::vector<Tensor> values) {
42 values_ = std::make_shared<std::vector<Tensor>>(std::move(values));
43 }
44
45 OptionalVariant(const OptionalVariant& other) : values_(other.values_) {}
46
47 // Returns true if `this` represents an actual value.
48 bool has_value() const { return values_ != nullptr; }
49
50 // REQUIRES: `this->has_value()` must be true.
51 const std::vector<Tensor>& get_values() const {
52 DCHECK(values_) << "Tried to get values from an empty OptionalVariant";
53 return *values_;
54 }
55
56 // Implementations of the necessary methods for using `OptionalVariant`
57 // objects in DT_VARIANT tensors.
58 string TypeName() const { return kOptionalVariantTypeName; }
59 void Encode(VariantTensorData* data) const {
60 data->set_metadata(values_ != nullptr);
61 if (values_ != nullptr) {
62 for (const auto& t : *values_) {
63 *(data->add_tensors()) = t;
64 }
65 }
66 }
67
68 bool Decode(const VariantTensorData& data) {
69 if (data.type_name() != TypeName()) {
70 return false;
71 }
72 bool has_value = false;
73 if (!data.get_metadata(&has_value)) {
74 return false;
75 }
76 if (has_value) {
77 values_ = std::make_shared<std::vector<Tensor>>(data.tensors());
78 } else {
79 values_.reset();
80 }
81 return true;
82 }
83
84 string DebugString() const {
85 if (values_) {
86 return strings::StrCat("OptionalVariant<", "values: (",
87 absl::StrJoin(*values_, ", ",
88 [](string* s, const Tensor& elem) {
89 *s = elem.DebugString();
90 }),
91 ")>");
92 } else {
93 return strings::StrCat("OptionalVariant<None>");
94 }
95 }
96
97 private:
98 std::shared_ptr<const std::vector<Tensor>> values_;
99};
100
101Status OptionalZerosLike(OpKernelContext* ctx, const OptionalVariant& x,
102 OptionalVariant* y,
103 std::function<Status(OpKernelContext* ctx,
104 const Tensor& input, Tensor* out)>
105 zeros_like_func);
106
107Status OptionalBinaryAdd(
108 OpKernelContext* ctx, const OptionalVariant& a, const OptionalVariant& b,
109 OptionalVariant* out,
110 std::function<Status(OpKernelContext* ctx, const Tensor& a, const Tensor& b,
111 Tensor* out)>
112 binary_add_func);
113
114} // namespace data
115} // namespace tensorflow
116
117#endif // TENSORFLOW_CORE_KERNELS_DATA_OPTIONAL_OPS_UTIL_H_
118