GCC Code Coverage Report

Line	Branch	Exec	Source
1			/*****************************************************************************
2			*
3			* Copyright (C) 2021 Richard Hacker (lerichi at gmx dot net),
4			* Florian Pose (fp at igh dot de),
5			* Bjarne von Horn (vh at igh dot de).
6			*
7			* This file is part of the PdCom library.
8			*
9			* The PdCom library is free software: you can redistribute it and/or modify
10			* it under the terms of the GNU Lesser General Public License as published by
11			* the Free Software Foundation, either version 3 of the License, or (at your
12			* option) any later version.
13			*
14			* The PdCom library is distributed in the hope that it will be useful, but
15			* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
16			* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
17			* License for more .
18			*
19			* You should have received a copy of the GNU Lesser General Public License
20			* along with the PdCom library. If not, see <http://www.gnu.org/licenses/>.
21			*
22			****************************************************************************/
23
24			/** @file */
25
26			#ifndef PDCOM5_SUBSCRIBER_H
27			#define PDCOM5_SUBSCRIBER_H
28
29			#include <chrono>
30			#include <functional>
31			#include <pdcom5/Exception.h>
32			#include <pdcom5_export.h>
33
34			namespace PdCom {
35
36			namespace impl {
37			class Subscription;
38			}
39
40			class Subscription;
41
42			/// Tag for event-based subscription.
43			constexpr struct event_mode_tag
44			{
45			} event_mode;
46
47			/// Tag for poll-based subscription.
48			constexpr struct poll_mode_tag
49			{
50			} poll_mode;
51
52			/** Transmission mode for subscriptions.
53			*
54			* This class specifies whether a Subscriber should get new values
55			* periodically, event-based or by polling only. Therefore, it is passed to
56			* the Subscribers' constructor. All Subscriptions registered with that
57			* subscriber will share the given transmission mode.
58			*/
59			class PDCOM5_PUBLIC Transmission
60			{
61			double interval_;
62
63		36	static constexpr double checkInterval(double d)
64			{
65	1/2 ✗ Branch 0 not taken. ✓ Branch 1 taken 36 times.	72	return d <= 0 ? throw PdCom::InvalidArgument(
66		✗	"period must be greater than zero")
67		36	: d;
68			}
69
70			public:
71		384	constexpr double getInterval() const noexcept { return interval_; }
72			template <typename T, typename R>
73		36	constexpr Transmission(std::chrono::duration<T, R> d) :
74	3/6 ✓ Branch 4 taken 1 times. ✗ Branch 5 not taken. ✓ Branch 10 taken 7 times. ✗ Branch 11 not taken. ✓ Branch 16 taken 28 times. ✗ Branch 17 not taken.	72	interval_(checkInterval(
75		72	std::chrono::duration_cast<std::chrono::duration<double>>(d)
76		36	.count()))
77		36	{}
78		307	constexpr Transmission(event_mode_tag) noexcept : interval_(0) {}
79		93	constexpr Transmission(poll_mode_tag) noexcept : interval_(-1) {}
80		423	bool operator==(const Transmission &o) const noexcept
81			{
82		423	return o.interval_ == interval_;
83			}
84
85			static constexpr Transmission fromDouble(double d)
86			{
87			return d == 0
88			? Transmission(event_mode)
89			: (d == -1 ? Transmission(poll_mode)
90			: Transmission(std::chrono::duration<double>(d)));
91			}
92			};
93
94			/** Base class for receiving notifications.
95			*
96			* This class is in charge of passing notifications from the library to client
97			* code. Make sure that the subscriber outlives all assigned subscriptions.
98			* Otherwise use-after-free bugs will occur, so be careful.
99			*
100			* The Subscriber class is also used to group subscriptions with the same
101			* transmission mode. The newValues method is called everytime, after all
102			* active subscriptions got their values updated for one realtime cycle.
103			*
104			* \example advanced_example.cpp
105			*/
106			class PDCOM5_PUBLIC Subscriber
107			{
108			Transmission td_;
109			friend class impl::Subscription;
110
111			public:
112		64	explicit Subscriber(const Transmission &td) noexcept : td_(td) {}
113			Subscriber(Subscriber const &) = delete;
114			Subscriber(Subscriber &&) = delete;
115			Subscriber &operator=(Subscriber const &) = delete;
116			Subscriber &operator=(Subscriber &&) = delete;
117
118		346	const Transmission &getTransmission() const noexcept { return td_; }
119
120			private:
121			/** Callback for an updated subscription state.
122			* @param subscription Subscription which was updated.
123			*/
124			virtual void stateChanged(PdCom::Subscription const &subscription) = 0;
125
126			/** Callback for new values.
127			*
128			* The epoch of \p time_ns depends on the clock selected in pdserv.
129			*
130			* Called after all active subscriptions got their values updated for one
131			* realtime cycle.
132			*
133			* @param time_ns Time since epoch in nanoseconds.
134			*/
135			virtual void newValues(std::chrono::nanoseconds time_ns) = 0;
136
137			protected:
138			~Subscriber() = default;
139			};
140
141			} // namespace PdCom
142
143			namespace std {
144
145			/** Hash implementation for PdCom::Transmission.
146			*
147			* Allows to use PdCom::Transmission as a key in std::unordered_map.
148			*/
149			template <>
150			struct hash<PdCom::Transmission>
151			{
152		172	size_t operator()(PdCom::Transmission t) const
153			noexcept(__cplusplus >= 201703L)
154			{
155		172	return std::hash<double>()(t.getInterval());
156			}
157			};
158
159			} // namespace std
160
161			#endif // PDCOM5_SUBSCRIBER_H
162