common/include/QtCore/qloggingcategory.h

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#ifndef QLOGGINGCATEGORY_H
#define QLOGGINGCATEGORY_H

#include <QtCore/qglobal.h>
#include <QtCore/qdebug.h>

QT_BEGIN_NAMESPACE

class Q_CORE_EXPORT QLoggingCategory
{
    Q_DISABLE_COPY(QLoggingCategory)
public:
    // ### Qt 6: Merge constructors
    explicit QLoggingCategory(const char *category);
    QLoggingCategory(const char *category, QtMsgType severityLevel);
    ~QLoggingCategory();

    bool isEnabled(QtMsgType type) const;
    void setEnabled(QtMsgType type, bool enable);

#ifdef Q_ATOMIC_INT8_IS_SUPPORTED
    bool isDebugEnabled() const { return bools.enabledDebug.load(); }
    bool isInfoEnabled() const { return bools.enabledInfo.load(); }
    bool isWarningEnabled() const { return bools.enabledWarning.load(); }
    bool isCriticalEnabled() const { return bools.enabledCritical.load(); }
#else
    bool isDebugEnabled() const { return enabled.load() >> DebugShift & 1; }
    bool isInfoEnabled() const { return enabled.load() >> InfoShift & 1; }
    bool isWarningEnabled() const { return enabled.load() >> WarningShift & 1; }
    bool isCriticalEnabled() const { return enabled.load() >> CriticalShift & 1; }
#endif
    const char *categoryName() const { return name; }

    // allows usage of both factory method and variable in qCX macros
    QLoggingCategory &operator()() { return *this; }
    const QLoggingCategory &operator()() const { return *this; }

    static QLoggingCategory *defaultCategory();

    typedef void (*CategoryFilter)(QLoggingCategory*);
    static CategoryFilter installFilter(CategoryFilter);

    static void setFilterRules(const QString &rules);

private:
    void init(const char *category, QtMsgType severityLevel);

    Q_DECL_UNUSED_MEMBER void *d; // reserved for future use
    const char *name;

#ifdef Q_BIG_ENDIAN
    enum { DebugShift = 0, WarningShift = 8, CriticalShift = 16, InfoShift = 24 };
#else
    enum { DebugShift = 24, WarningShift = 16, CriticalShift = 8, InfoShift = 0};
#endif

    struct AtomicBools {
#ifdef Q_ATOMIC_INT8_IS_SUPPORTED
        QBasicAtomicInteger<bool> enabledDebug;
        QBasicAtomicInteger<bool> enabledWarning;
        QBasicAtomicInteger<bool> enabledCritical;
        QBasicAtomicInteger<bool> enabledInfo;
#endif
    };
    union {
        AtomicBools bools;
        QBasicAtomicInt enabled;
    };
    Q_DECL_UNUSED_MEMBER bool placeholder[4]; // reserved for future use
};

#define Q_DECLARE_LOGGING_CATEGORY(name) \
    extern const QLoggingCategory &name();

#if defined(Q_COMPILER_VARIADIC_MACROS) || defined(Q_MOC_RUN)

#define Q_LOGGING_CATEGORY(name, ...) \
    const QLoggingCategory &name() \
    { \
        static const QLoggingCategory category(__VA_ARGS__); \
        return category; \
    }

#define qCDebug(category, ...) \
    for (bool qt_category_enabled = category().isDebugEnabled(); qt_category_enabled; qt_category_enabled = false) \
        QMessageLogger(QT_MESSAGELOG_FILE, QT_MESSAGELOG_LINE, QT_MESSAGELOG_FUNC, category().categoryName()).debug(__VA_ARGS__)
#define qCInfo(category, ...) \
    for (bool qt_category_enabled = category().isInfoEnabled(); qt_category_enabled; qt_category_enabled = false) \
        QMessageLogger(QT_MESSAGELOG_FILE, QT_MESSAGELOG_LINE, QT_MESSAGELOG_FUNC, category().categoryName()).info(__VA_ARGS__)
#define qCWarning(category, ...) \
    for (bool qt_category_enabled = category().isWarningEnabled(); qt_category_enabled; qt_category_enabled = false) \
        QMessageLogger(QT_MESSAGELOG_FILE, QT_MESSAGELOG_LINE, QT_MESSAGELOG_FUNC, category().categoryName()).warning(__VA_ARGS__)
#define qCCritical(category, ...) \
    for (bool qt_category_enabled = category().isCriticalEnabled(); qt_category_enabled; qt_category_enabled = false) \
        QMessageLogger(QT_MESSAGELOG_FILE, QT_MESSAGELOG_LINE, QT_MESSAGELOG_FUNC, category().categoryName()).critical(__VA_ARGS__)

#else // defined(Q_COMPILER_VARIADIC_MACROS) || defined(Q_MOC_RUN)

// Optional msgType argument not supported
#define Q_LOGGING_CATEGORY(name, string) \
    const QLoggingCategory &name() \
    { \
        static const QLoggingCategory category(string); \
        return category; \
    }

// check for enabled category inside QMessageLogger.
#define qCDebug qDebug
#define qCInfo qInfo
#define qCWarning qWarning
#define qCCritical qCritical

#endif // Q_COMPILER_VARIADIC_MACROS || defined(Q_MOC_RUN)

#if defined(QT_NO_DEBUG_OUTPUT)
#  undef qCDebug
#  define qCDebug(category) QT_NO_QDEBUG_MACRO()
#endif
#if defined(QT_NO_INFO_OUTPUT)
#  undef qCInfo
#  define qCInfo(category) QT_NO_QDEBUG_MACRO()
#endif
#if defined(QT_NO_WARNING_OUTPUT)
#  undef qCWarning
#  define qCWarning(category) QT_NO_QDEBUG_MACRO()
#endif

QT_END_NAMESPACE

#endif // QLOGGINGCATEGORY_H