1 #pragma once
2 #include <cstdint>
3 #include <string>
4 
5 namespace phosphor
6 {
7 namespace fan
8 {
9 namespace presence
10 {
11 
12 /**
13  * @class PresenceSensor
14  * @brief PresenceSensor interface.
15  *
16  * Provide concrete implementations of PresenceSensor to realize
17  * new presence detection methods.
18  *
19  * Note that implementations drive the inventory update process via
20  * a redundancy policy (rpolicy.hpp) - it is not enough to implement
21  * the interfaces below.
22  */
23 class PresenceSensor
24 {
25   public:
26     PresenceSensor(const PresenceSensor&) = default;
27     PresenceSensor& operator=(const PresenceSensor&) = default;
28     PresenceSensor(PresenceSensor&&) = default;
29     PresenceSensor& operator=(PresenceSensor&&) = default;
30     virtual ~PresenceSensor() = default;
31     PresenceSensor() : id(nextId)
32     {
33         nextId++;
34     }
35 
36     /**
37      * @brief start
38      *
39      * Implementations should peform any preparation
40      * for detecting presence.  Typical implementations
41      * might register signal callbacks or start
42      * a polling loop.
43      *
44      * @return The state of the sensor.
45      */
46     virtual bool start() = 0;
47 
48     /**
49      * @brief stop
50      *
51      * Implementations should stop issuing presence
52      * state change notifications.  Typical implementations
53      * might de-register signal callbacks or terminate
54      * polling loops.
55      */
56     virtual void stop() = 0;
57 
58     /**
59      * @brief Check the sensor.
60      *
61      * Implementations should perform an offline (the start
62      * method has not been invoked) query of the presence
63      * state.
64      *
65      * @return The state of the sensor.
66      */
67     virtual bool present() = 0;
68 
69     /**
70      * @brief Mark the sensor as failed.
71      *
72      * Implementations should log an an event if the
73      * system policy requires it.
74      *
75      * Provide a default noop implementation.
76      */
77     virtual void fail() {}
78 
79     friend bool operator==(const PresenceSensor& l, const PresenceSensor& r);
80 
81     /**
82      * @brief Called when this presence sensor doesn't agree with other ones.
83      *
84      * @param[in] fanInventoryPath - The fan inventory D-Bus object path.
85      */
86     virtual void logConflict(const std::string& fanInventoryPath) const = 0;
87 
88   private:
89     /** @brief Unique sensor ID. */
90     std::size_t id;
91 
92     /** @brief The next unique sensor ID. */
93     static std::size_t nextId;
94 };
95 
96 inline bool operator==(const PresenceSensor& l, const PresenceSensor& r)
97 {
98     return l.id == r.id;
99 }
100 
101 } // namespace presence
102 } // namespace fan
103 } // namespace phosphor
104