1//
2// Copyright (C) 2014 The Android Open Source Project
3//
4// Licensed under the Apache License, Version 2.0 (the "License");
5// you may not use this file except in compliance with the License.
6// You may obtain a copy of the License at
7//
8//      http://www.apache.org/licenses/LICENSE-2.0
9//
10// Unless required by applicable law or agreed to in writing, software
11// distributed under the License is distributed on an "AS IS" BASIS,
12// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13// See the License for the specific language governing permissions and
14// limitations under the License.
15//
16
17#ifndef UPDATE_ENGINE_UPDATE_MANAGER_RANDOM_PROVIDER_H_
18#define UPDATE_ENGINE_UPDATE_MANAGER_RANDOM_PROVIDER_H_
19
20#include "update_engine/update_manager/provider.h"
21#include "update_engine/update_manager/variable.h"
22
23namespace chromeos_update_manager {
24
25// Provider of random values.
26class RandomProvider : public Provider {
27 public:
28  ~RandomProvider() override {}
29
30  // Return a random number every time it is requested. Note that values
31  // returned by the variables are cached by the EvaluationContext, so the
32  // returned value will be the same during the same policy request. If more
33  // random values are needed use a PRNG seeded with this value.
34  virtual Variable<uint64_t>* var_seed() = 0;
35
36 protected:
37  RandomProvider() {}
38
39 private:
40  DISALLOW_COPY_AND_ASSIGN(RandomProvider);
41};
42
43}  // namespace chromeos_update_manager
44
45#endif  // UPDATE_ENGINE_UPDATE_MANAGER_RANDOM_PROVIDER_H_
46