1/* Copyright 2015 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
16// See docs in ../ops/io_ops.cc.
17
18#include <memory>
19
20#include "absl/strings/escaping.h"
21#include "tensorflow/core/framework/reader_base.h"
22#include "tensorflow/core/framework/reader_base.pb.h"
23#include "tensorflow/core/framework/reader_op_kernel.h"
24#include "tensorflow/core/lib/core/errors.h"
25#include "tensorflow/core/lib/strings/str_util.h"
26#include "tensorflow/core/lib/strings/strcat.h"
27#include "tensorflow/core/platform/protobuf.h"
28
29namespace tensorflow {
30
31class IdentityReader : public ReaderBase {
32 public:
33 explicit IdentityReader(const string& node_name)
34 : ReaderBase(strings::StrCat("IdentityReader '", node_name, "'")) {}
35
36 Status ReadLocked(tstring* key, tstring* value, bool* produced,
37 bool* at_end) override {
38 *key = current_work();
39 *value = current_work();
40 *produced = true;
41 *at_end = true;
42 return OkStatus();
43 }
44
45 // Stores state in a ReaderBaseState proto, since IdentityReader has
46 // no additional state beyond ReaderBase.
47 Status SerializeStateLocked(tstring* state) override {
48 ReaderBaseState base_state;
49 SaveBaseState(&base_state);
50 SerializeToTString(base_state, state);
51 return OkStatus();
52 }
53
54 Status RestoreStateLocked(const tstring& state) override {
55 ReaderBaseState base_state;
56 if (!ParseProtoUnlimited(&base_state, state)) {
57 return errors::InvalidArgument("Could not parse state for ", name(), ": ",
58 absl::CEscape(state));
59 }
60 TF_RETURN_IF_ERROR(RestoreBaseState(base_state));
61 return OkStatus();
62 }
63};
64
65class IdentityReaderOp : public ReaderOpKernel {
66 public:
67 explicit IdentityReaderOp(OpKernelConstruction* context)
68 : ReaderOpKernel(context) {
69 SetReaderFactory([this]() { return new IdentityReader(name()); });
70 }
71};
72
73REGISTER_KERNEL_BUILDER(Name("IdentityReader").Device(DEVICE_CPU),
74 IdentityReaderOp);
75REGISTER_KERNEL_BUILDER(Name("IdentityReaderV2").Device(DEVICE_CPU),
76 IdentityReaderOp);
77
78} // namespace tensorflow
79