summaryrefslogtreecommitdiffstats
path: root/src/common/logging/backend.h
blob: ae270efe816e3540b0f662a7806dbc62efccd89c (plain) (blame)
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
133
134
// Copyright 2014 Citra Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

#pragma once

#include <cstdarg>
#include <memory>
#include <vector>

#include "common/concurrent_ring_buffer.h"

#include "common/logging/log.h"

namespace Log {

/**
 * A log entry. Log entries are store in a structured format to permit more varied output
 * formatting on different frontends, as well as facilitating filtering and aggregation.
 */
struct Entry {
    std::chrono::microseconds timestamp;
    Class log_class;
    Level log_level;
    std::string location;
    std::string message;

    Entry() = default;

    // TODO(yuriks) Use defaulted move constructors once MSVC supports them
#define MOVE(member) member(std::move(o.member))
    Entry(Entry&& o)
        : MOVE(timestamp), MOVE(log_class), MOVE(log_level),
        MOVE(location), MOVE(message)
    {}
#undef MOVE

    Entry& operator=(const Entry&& o) {
#define MOVE(member) member = std::move(o.member)
        MOVE(timestamp);
        MOVE(log_class);
        MOVE(log_level);
        MOVE(location);
        MOVE(message);
#undef MOVE
        return *this;
    }
};

struct ClassInfo {
    Class log_class;

    /**
        * Total number of (direct or indirect) sub classes this class has. If any, they follow in
        * sequence after this class in the class list.
        */
    unsigned int num_children = 0;

    ClassInfo(Class log_class) : log_class(log_class) {}
};

/**
 * Logging management class. This class has the dual purpose of acting as an exchange point between
 * the logging clients and the log outputter, as well as containing reflection info about available
 * log classes.
 */
class Logger {
private:
    using Buffer = Common::ConcurrentRingBuffer<Entry, 16 * 1024 / sizeof(Entry)>;

public:
    static const size_t QUEUE_CLOSED = Buffer::QUEUE_CLOSED;

    Logger();

    /**
     * Returns a list of all vector classes and subclasses. The sequence returned is a pre-order of
     * classes and subclasses, which together with the `num_children` field in ClassInfo, allows
     * you to recover the hierarchy.
     */
    const std::vector<ClassInfo>& GetClasses() const { return all_classes; }

    /**
     * Returns the name of the passed log class as a C-string. Subclasses are separated by periods
     * instead of underscores as in the enumeration.
     */
    static const char* GetLogClassName(Class log_class);

    /**
     * Returns the name of the passed log level as a C-string.
     */
    static const char* GetLevelName(Level log_level);

    /**
     * Appends a messages to the log buffer.
     * @note This function is thread safe.
     */
    void LogMessage(Entry entry);

    /**
     * Retrieves a batch of messages from the log buffer, blocking until they are available.
     * @note This function is thread safe.
     *
     * @param out_buffer Destination buffer that will receive the log entries.
     * @param buffer_len The maximum size of `out_buffer`.
     * @return The number of entries stored. In case the logger is shutting down, `QUEUE_CLOSED` is
     *         returned, no entries are stored and the logger should shutdown.
     */
    size_t GetEntries(Entry* out_buffer, size_t buffer_len);

    /**
     * Initiates a shutdown of the logger. This will indicate to log output clients that they
     * should shutdown.
     */
    void Close() { ring_buffer.Close(); }

    /**
     * Returns true if Close() has already been called on the Logger.
     */
    bool IsClosed() const { return ring_buffer.IsClosed(); }

private:
    Buffer ring_buffer;
    std::vector<ClassInfo> all_classes;
};

/// Creates a log entry by formatting the given source location, and message.
Entry CreateEntry(Class log_class, Level log_level,
                        const char* filename, unsigned int line_nr, const char* function,
                        const char* format, va_list args);
/// Initializes the default Logger.
std::shared_ptr<Logger> InitGlobalLogger();

}