ftrace.h

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/*
    KWin - the KDE window manager
    This file is part of the KDE project.
 
    SPDX-FileCopyrightText: 2021 David Edmundson <davidedmundson@kde.org>
 
    SPDX-License-Identifier: LGPL-2.0-or-later
*/
 
#pragma once
 
#include "effect/globals.h"
 
#include <QFile>
#include <QMutex>
#include <QMutexLocker>
#include <QObject>
#include <QTextStream>
 
namespace KWin
{
class KWIN_EXPORT FTraceLogger : public QObject
{
    Q_OBJECT
    Q_CLASSINFO("D-Bus Interface", "org.kde.kwin.FTrace");
    Q_PROPERTY(bool isEnabled READ isEnabled NOTIFY enabledChanged)
 
public:
    bool isEnabled() const;
 
    template<typename... Args>
    void trace(Args... args)
    {
        Q_ASSERT(isEnabled());
        QMutexLocker lock(&m_mutex);
        if (!m_file.isOpen()) {
            return;
        }
        QTextStream stream(&m_file);
        (stream << ... << args) << Qt::endl;
    }
 
Q_SIGNALS:
    void enabledChanged();
 
public Q_SLOTS:
    Q_SCRIPTABLE void setEnabled(bool enabled);
 
private:
    static QString filePath();
    bool open();
    QFile m_file;
    QMutex m_mutex;
    KWIN_SINGLETON(FTraceLogger)
};
 
class KWIN_EXPORT FTraceDuration
{
public:
    template<typename... Args>
    FTraceDuration(Args... args)
    {
        static QAtomicInteger<quint32> s_context = 0;
        QTextStream stream(&m_message);
        (stream << ... << args);
        stream.flush();
        m_context = ++s_context;
        FTraceLogger::self()->trace(m_message, " begin_ctx=", m_context);
    }
 
    ~FTraceDuration();
 
private:
    QByteArray m_message;
    quint32 m_context;
};
 
} // namespace KWin
 
#define fTrace(...)                              \
    if (KWin::FTraceLogger::self()->isEnabled()) \
        KWin::FTraceLogger::self()->trace(__VA_ARGS__);
 
#define fTraceDuration(...) \
    std::unique_ptr<KWin::FTraceDuration> _duration(KWin::FTraceLogger::self()->isEnabled() ? new KWin::FTraceDuration(__VA_ARGS__) : nullptr);