summaryrefslogtreecommitdiff
path: root/src/ipa/raspberrypi/controller/metadata.hpp
blob: e735cfbe04808f1db8c2ff13065af98f32f5f82f (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
/* SPDX-License-Identifier: BSD-2-Clause */
/*
 * Copyright (C) 2019-2021, Raspberry Pi (Trading) Limited
 *
 * metadata.hpp - general metadata class
 */
#pragma once

// A simple class for carrying arbitrary metadata, for example about an image.

#include <any>
#include <map>
#include <memory>
#include <mutex>
#include <string>

namespace RPiController {

class Metadata
{
public:
	template<typename T>
	void Set(std::string const &tag, T const &value)
	{
		std::scoped_lock lock(mutex_);
		data_[tag] = value;
	}

	template<typename T>
	int Get(std::string const &tag, T &value) const
	{
		std::scoped_lock lock(mutex_);
		auto it = data_.find(tag);
		if (it == data_.end())
			return -1;
		value = std::any_cast<T>(it->second);
		return 0;
	}

	void Clear()
	{
		std::scoped_lock lock(mutex_);
		data_.clear();
	}

	Metadata &operator=(Metadata const &other)
	{
		std::scoped_lock lock(mutex_, other.mutex_);
		data_ = other.data_;
		return *this;
	}

	template<typename T>
	T *GetLocked(std::string const &tag)
	{
		// This allows in-place access to the Metadata contents,
		// for which you should be holding the lock.
		auto it = data_.find(tag);
		if (it == data_.end())
			return nullptr;
		return std::any_cast<T>(&it->second);
	}

	template<typename T>
	void SetLocked(std::string const &tag, T const &value)
	{
		// Use this only if you're holding the lock yourself.
		data_[tag] = value;
	}

	// Note: use of (lowercase) lock and unlock means you can create scoped
	// locks with the standard lock classes.
	// e.g. std::lock_guard<RPiController::Metadata> lock(metadata)
	void lock() { mutex_.lock(); }
	void unlock() { mutex_.unlock(); }

private:
	mutable std::mutex mutex_;
	std::map<std::string, std::any> data_;
};

typedef std::shared_ptr<Metadata> MetadataPtr;

} // namespace RPiController