Blame view

src/mqttidgenerator.cpp 3.84 KB
b5d9e433   Peter M. Groen   Fixed License Hea...
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
  /* ****************************************************************************
   * Copyright 2019 Open Systems Development BV                                 *
   *                                                                            *
   * Permission is hereby granted, free of charge, to any person obtaining a    *
   * copy of this software and associated documentation files (the "Software"), *
   * to deal in the Software without restriction, including without limitation  *
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,   *
   * and/or sell copies of the Software, and to permit persons to whom the      *
   * Software is furnished to do so, subject to the following conditions:       *
   *                                                                            *
   * The above copyright notice and this permission notice shall be included in *
   * all copies or substantial portions of the Software.                        *
   *                                                                            *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR *
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,   *
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL    *
   * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER *
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING    *
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER        *
   * DEALINGS IN THE SOFTWARE.                                                  *
   * ***************************************************************************/
51becbde   Peter M. Groen   Committed the ent...
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
  #include "mqttidgenerator.h"
  
  // std
  #include <chrono>
  #include <mutex>
  #include <thread>
  #include <unistd.h>
  
  // boost
  #include <boost/uuid/uuid_generators.hpp>
  
  #include "lockguard.h"
  #include "commondefs.h"
  
  namespace {
  
  boost::uuids::basic_random_generator<boost::mt19937> createGenerator()
  {
      static auto timeSeed = static_cast<boost::mt19937::result_type>(std::chrono::duration_cast<std::chrono::nanoseconds>(std::chrono::high_resolution_clock::now().time_since_epoch()).count());
      static auto pidSeed = static_cast<boost::mt19937::result_type>(getpid());
      static std::hash<std::thread::id> hasher;
      static auto threadSeed = static_cast<boost::mt19937::result_type>(hasher(std::this_thread::get_id()));
      static boost::mt19937 randomNumberGenerator;
      randomNumberGenerator.seed(timeSeed ^ pidSeed ^ threadSeed);
      return boost::uuids::basic_random_generator<boost::mt19937>(&randomNumberGenerator);
  }
  
  } // namespace
  
  using namespace osdev::components::mqtt;
  
  const MqttId mqttNamespace = boost::lexical_cast<boost::uuids::uuid>("9c0f3730-cc4f-49eb-ab5b-079bc5b0e481");
  
  // static
  MqttId MqttIdGenerator::generate()
  {
      // From the boost design notes
      // Seeding is unqiue per random generator:
      // The boost::uuids::basic_random_generator class' default constructor seeds the random number generator
      //  with a SHA-1 hash of a number of different values including std::time(0), std::clock(), uninitialized data,
      //  value return from new unsigned int, etc..
      // Functions are reentrant:
      // All functions are re-entrant. Classes are as thread-safe as an int. That is an instance can not be shared
      //  between threads without proper synchronization.
      static auto uuidGenerator = createGenerator();
      static std::mutex generatorMutex;
      OSDEV_COMPONENTS_LOCKGUARD(generatorMutex);
      return uuidGenerator();
  }
  
  //static
  MqttId MqttIdGenerator::nullId()
  {
      return boost::uuids::nil_uuid();
  }
  
  // static
  MqttId MqttIdGenerator::nameId(MqttId namespaceUuid, const std::string& name)
  {
      boost::uuids::name_generator gen(namespaceUuid);
      return gen(name.c_str());
  }
  
  // static
  MqttId MqttIdGenerator::nameId(const std::string& name)
  {
      return MqttIdGenerator::nameId(mqttNamespace, name);
  }