log.h

Go to the documentation of this file.

/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2018, Google Inc.
 *
 * Logging infrastructure
 */

#pragma once

#include <atomic>
#include <sstream>
#include <string_view>

#include <libcamera/base/private.h>

#include <libcamera/base/class.h>
#include <libcamera/base/utils.h>

namespace libcamera {

enum LogSeverity {
    LogInvalid = -1,
    LogDebug = 0,
    LogInfo,
    LogWarning,
    LogError,
    LogFatal,
};

class LogCategory
{
public:
    static LogCategory *create(std::string_view name);

    const std::string &name() const { return name_; }
    LogSeverity severity() const { return severity_.load(std::memory_order_relaxed); }
    void setSeverity(LogSeverity severity) { severity_.store(severity, std::memory_order_relaxed); }

    static const LogCategory &defaultCategory();

private:
    friend class Logger;
    explicit LogCategory(std::string_view name);

    const std::string name_;

    std::atomic<LogSeverity> severity_;
    static_assert(decltype(severity_)::is_always_lock_free);
};

#define LOG_DECLARE_CATEGORY(name)                  \
extern const LogCategory &_LOG_CATEGORY(name)();

#define LOG_DEFINE_CATEGORY(name)                   \
LOG_DECLARE_CATEGORY(name)                      \
const LogCategory &_LOG_CATEGORY(name)()                \
{                                   \
    /* The instance will be deleted by the Logger destructor. */    \
    static LogCategory *category = LogCategory::create(#name);  \
    return *category;                       \
}

class LogMessage
{
public:
    LogMessage(const char *fileName, unsigned int line,
           const LogCategory &category, LogSeverity severity,
           std::string prefix = {});
    ~LogMessage();

    std::ostream &stream() { return msgStream_; }

    const utils::time_point &timestamp() const { return timestamp_; }
    LogSeverity severity() const { return severity_; }
    const LogCategory &category() const { return category_; }
    const std::string &fileInfo() const { return fileInfo_; }
    const std::string &prefix() const { return prefix_; }
    const std::string msg() const { return msgStream_.str(); }

private:
    LIBCAMERA_DISABLE_COPY_AND_MOVE(LogMessage)

    std::ostringstream msgStream_;
    const LogCategory &category_;
    LogSeverity severity_;
    utils::time_point timestamp_;
    std::string fileInfo_;
    std::string prefix_;
};

class Loggable
{
public:
    virtual ~Loggable();

protected:
    virtual std::string logPrefix() const = 0;

    LogMessage _log(const LogCategory *category, LogSeverity severity,
            const char *fileName = __builtin_FILE(),
            unsigned int line = __builtin_LINE()) const;
};

LogMessage _log(const LogCategory *category, LogSeverity severity,
        const char *fileName = __builtin_FILE(),
        unsigned int line = __builtin_LINE());

#ifndef __DOXYGEN__
#define _LOG_CATEGORY(name) logCategory##name

#define _LOG1(severity) \
    _log(nullptr, Log##severity).stream()
#define _LOG2(category, severity) \
    _log(&_LOG_CATEGORY(category)(), Log##severity).stream()

/*
 * Expand the LOG() macro to _LOG1() or _LOG2() based on the number of
 * arguments.
 */
#define _LOG_MACRO(_1, _2, NAME, ...) NAME
#define LOG(...) _LOG_MACRO(__VA_ARGS__, _LOG2, _LOG1)(__VA_ARGS__)
#else /* __DOXYGEN___ */
#define LOG(category, severity)
#endif /* __DOXYGEN__ */

#ifndef NDEBUG
#define ASSERT(condition) static_cast<void>(({                          \
    if (!(condition))                                               \
        LOG(Fatal) << "assertion \"" #condition "\" failed in " \
               << __func__ << "()";                         \
}))
#else
#define ASSERT(condition) static_cast<void>(false && (condition))
#endif

} /* namespace libcamera */