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1 /* Copyright 2016 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 /// SavedModel loading functions and SavedModelBundle struct.
17 
18 #ifndef TENSORFLOW_CC_SAVED_MODEL_LOADER_H_
19 #define TENSORFLOW_CC_SAVED_MODEL_LOADER_H_
20 
21 #include <string>
22 #include <unordered_set>
23 
24 #include "tensorflow/core/lib/core/status.h"
25 #include "tensorflow/core/protobuf/graph_debug_info.pb.h"
26 #include "tensorflow/core/protobuf/meta_graph.pb.h"
27 #include "tensorflow/core/public/session.h"
28 
29 namespace tensorflow {
30 
31 /// Represents a SavedModel that is loaded from storage.
32 class SavedModelBundleInterface {
33  public:
34   virtual ~SavedModelBundleInterface();
35 
36   /// Returns the TensorFlow Session that can be used to interact with the
37   /// SavedModel.
38   virtual Session* GetSession() const = 0;
39 
40   /// Returns a map from signature name to SignatureDef for all signatures in
41   /// in the SavedModel.
42   virtual const protobuf::Map<string, SignatureDef>& GetSignatures() const = 0;
43 };
44 
45 /// SavedModel representation once the SavedModel is loaded from storage.
46 ///
47 /// NOTE: Prefer to use SavedModelBundleLite in new code, as it consumes less
48 /// RAM.
49 struct SavedModelBundle : public SavedModelBundleInterface {
50   /// A TensorFlow Session does not Close itself on destruction. To avoid
51   /// resource leaks, we explicitly call Close on Sessions that we create.
~SavedModelBundleSavedModelBundle52   ~SavedModelBundle() override {
53     if (session) {
54       session->Close().IgnoreError();
55     }
56   }
57 
58   SavedModelBundle() = default;
59 
GetSessionSavedModelBundle60   Session* GetSession() const override { return session.get(); }
GetSignaturesSavedModelBundle61   const protobuf::Map<string, SignatureDef>& GetSignatures() const override {
62     return meta_graph_def.signature_def();
63   }
64 
65   std::unique_ptr<Session> session;
66   MetaGraphDef meta_graph_def;
67   std::unique_ptr<GraphDebugInfo> debug_info;
68 };
69 
70 // A version of SavedModelBundle that avoids storing a potentially large
71 // MetaGraphDef. Prefer to use SavedModelBundleLite in new code.
72 class SavedModelBundleLite : public SavedModelBundleInterface {
73  public:
74   SavedModelBundleLite() = default;
75   SavedModelBundleLite& operator=(SavedModelBundleLite&& other) = default;
76 
SavedModelBundleLite(std::unique_ptr<Session> session,protobuf::Map<string,SignatureDef> signatures)77   SavedModelBundleLite(std::unique_ptr<Session> session,
78                        protobuf::Map<string, SignatureDef> signatures)
79       : session_(std::move(session)), signatures_(std::move(signatures)) {}
80 
81   /// A TensorFlow Session does not Close itself on destruction. To avoid
82   /// resource leaks, we explicitly call Close on Sessions that we create.
~SavedModelBundleLite()83   ~SavedModelBundleLite() override {
84     if (session_) {
85       session_->Close().IgnoreError();
86     }
87   }
88 
GetSession()89   Session* GetSession() const override { return session_.get(); }
GetSignatures()90   const protobuf::Map<string, SignatureDef>& GetSignatures() const override {
91     return signatures_;
92   }
93 
94  private:
95   std::unique_ptr<Session> session_;
96   protobuf::Map<string, SignatureDef> signatures_;
97 };
98 
99 /// Loads a SavedModel from the specified export directory. The MetaGraphDef
100 /// to be loaded is identified by the supplied tags, corresponding exactly to
101 /// the set of tags used at SavedModel build time. Stores a SavedModel bundle in
102 /// *bundle with a session and the requested MetaGraphDef, if found.
103 ///
104 /// NOTE: Prefer the overload that takes a SavedModelBundleLite* in new code.
105 Status LoadSavedModel(const SessionOptions& session_options,
106                       const RunOptions& run_options, const string& export_dir,
107                       const std::unordered_set<string>& tags,
108                       SavedModelBundle* const bundle);
109 
110 /// Loads a SavedModel from the specified export directory. The MetaGraphDef
111 /// to be loaded is identified by the supplied tags, corresponding exactly to
112 /// the set of tags used at SavedModel build time. Stores a SavedModel bundle
113 /// in *bundle with a session created from the requested MetaGraphDef if found.
114 ///
115 /// This overload creates a SavedModelBundleLite, which consumes less RAM than
116 /// an equivalent SavedModelBundle.
117 Status LoadSavedModel(const SessionOptions& session_options,
118                       const RunOptions& run_options, const string& export_dir,
119                       const std::unordered_set<string>& tags,
120                       SavedModelBundleLite* const bundle);
121 
122 /// Checks whether the provided directory could contain a SavedModel. Note that
123 /// the method does not load any data by itself. If the method returns `false`,
124 /// the export directory definitely does not contain a SavedModel. If the method
125 /// returns `true`, the export directory may contain a SavedModel but provides
126 /// no guarantee that it can be loaded.
127 bool MaybeSavedModelDirectory(const string& export_dir);
128 
129 }  // namespace tensorflow
130 
131 #endif  // TENSORFLOW_CC_SAVED_MODEL_LOADER_H_
132