summaryrefslogtreecommitdiff
path: root/include/libcamera/base/signal.h
blob: c2521769a8433c2413c124842d416f5461e55d6a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
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
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2019, Google Inc.
 *
 * signal.h - Signal & slot implementation
 */
#ifndef __LIBCAMERA_BASE_SIGNAL_H__
#define __LIBCAMERA_BASE_SIGNAL_H__

#include <functional>
#include <list>
#include <type_traits>
#include <vector>

#include <libcamera/base/bound_method.h>
#include <libcamera/base/object.h>

namespace libcamera {

class SignalBase
{
public:
	void disconnect(Object *object);

protected:
	using SlotList = std::list<BoundMethodBase *>;

	void connect(BoundMethodBase *slot);
	void disconnect(std::function<bool(SlotList::iterator &)> match);

	SlotList slots();

private:
	SlotList slots_;
};

template<typename... Args>
class Signal : public SignalBase
{
public:
	~Signal()
	{
		disconnect();
	}

#ifndef __DOXYGEN__
	template<typename T, typename R, typename std::enable_if_t<std::is_base_of<Object, T>::value> * = nullptr>
	void connect(T *obj, R (T::*func)(Args...),
		     ConnectionType type = ConnectionTypeAuto)
	{
		Object *object = static_cast<Object *>(obj);
		SignalBase::connect(new BoundMethodMember<T, R, Args...>(obj, object, func, type));
	}

	template<typename T, typename R, typename std::enable_if_t<!std::is_base_of<Object, T>::value> * = nullptr>
#else
	template<typename T, typename R>
#endif
	void connect(T *obj, R (T::*func)(Args...))
	{
		SignalBase::connect(new BoundMethodMember<T, R, Args...>(obj, nullptr, func));
	}

	template<typename R>
	void connect(R (*func)(Args...))
	{
		SignalBase::connect(new BoundMethodStatic<R, Args...>(func));
	}

	void disconnect()
	{
		SignalBase::disconnect([]([[maybe_unused]] SlotList::iterator &iter) {
			return true;
		});
	}

	template<typename T>
	void disconnect(T *obj)
	{
		SignalBase::disconnect([obj](SlotList::iterator &iter) {
			return (*iter)->match(obj);
		});
	}

	template<typename T, typename R>
	void disconnect(T *obj, R (T::*func)(Args...))
	{
		SignalBase::disconnect([obj, func](SlotList::iterator &iter) {
			BoundMethodArgs<R, Args...> *slot =
				static_cast<BoundMethodArgs<R, Args...> *>(*iter);

			if (!slot->match(obj))
				return false;

			/*
			 * If the object matches the slot, the slot is
			 * guaranteed to be a member slot, so we can safely
			 * cast it to BoundMethodMember<T, Args...> to match
			 * func.
			 */
			return static_cast<BoundMethodMember<T, R, Args...> *>(slot)->match(func);
		});
	}

	template<typename R>
	void disconnect(R (*func)(Args...))
	{
		SignalBase::disconnect([func](SlotList::iterator &iter) {
			BoundMethodArgs<R, Args...> *slot =
				static_cast<BoundMethodArgs<R, Args...> *>(*iter);

			if (!slot->match(nullptr))
				return false;

			return static_cast<BoundMethodStatic<R, Args...> *>(slot)->match(func);
		});
	}

	void emit(Args... args)
	{
		/*
		 * Make a copy of the slots list as the slot could call the
		 * disconnect operation, invalidating the iterator.
		 */
		for (BoundMethodBase *slot : slots())
			static_cast<BoundMethodArgs<void, Args...> *>(slot)->activate(args...);
	}
};

} /* namespace libcamera */

#endif /* __LIBCAMERA_BASE_SIGNAL_H__ */