include/QtCore/qloggingcategory.h

0001 // Copyright (C) 2016 The Qt Company Ltd.
0002 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
0003
0004 #ifndef QLOGGINGCATEGORY_H
0005 #define QLOGGINGCATEGORY_H
0006
0007 #include <QtCore/qglobal.h>
0008 #include <QtCore/qdebug.h>
0009
0010 QT_BEGIN_NAMESPACE
0011
0012 class Q_CORE_EXPORT QLoggingCategory
0013 {
0014     Q_DISABLE_COPY(QLoggingCategory)
0015 public:
0016     explicit QLoggingCategory(const char *category, QtMsgType severityLevel = QtDebugMsg);
0017     ~QLoggingCategory();
0018
0019     bool isEnabled(QtMsgType type) const;
0020     void setEnabled(QtMsgType type, bool enable);
0021
0022     bool isDebugEnabled() const { return bools.enabledDebug.loadRelaxed(); }
0023     bool isInfoEnabled() const { return bools.enabledInfo.loadRelaxed(); }
0024     bool isWarningEnabled() const { return bools.enabledWarning.loadRelaxed(); }
0025     bool isCriticalEnabled() const { return bools.enabledCritical.loadRelaxed(); }
0026
0027     const char *categoryName() const { return name; }
0028
0029     // allows usage of both factory method and variable in qCX macros
0030     QLoggingCategory &operator()() { return *this; }
0031     const QLoggingCategory &operator()() const { return *this; }
0032
0033     static QLoggingCategory *defaultCategory();
0034
0035     typedef void (*CategoryFilter)(QLoggingCategory*);
0036     static CategoryFilter installFilter(CategoryFilter);
0037
0038     static void setFilterRules(const QString &rules);
0039
0040 private:
0041     void init(const char *category, QtMsgType severityLevel);
0042
0043     Q_DECL_UNUSED_MEMBER void *d; // reserved for future use
0044     const char *name;
0045
0046     struct AtomicBools {
0047         QBasicAtomicInteger<bool> enabledDebug;
0048         QBasicAtomicInteger<bool> enabledWarning;
0049         QBasicAtomicInteger<bool> enabledCritical;
0050         QBasicAtomicInteger<bool> enabledInfo;
0051     };
0052     union {
0053         AtomicBools bools;
0054         QBasicAtomicInt enabled;
0055     };
0056     Q_DECL_UNUSED_MEMBER bool placeholder[4]; // reserved for future use
0057 };
0058
0059 namespace { // allow different TUs to have different QT_NO_xxx_OUTPUT
0060 template <QtMsgType Which> struct QLoggingCategoryMacroHolder
0061 {
0062     static const bool IsOutputEnabled;
0063     const QLoggingCategory *category = nullptr;
0064     bool control = false;
0065     explicit QLoggingCategoryMacroHolder(const QLoggingCategory &cat)
0066     {
0067         if (IsOutputEnabled)
0068             init(cat);
0069     }
0070     void init(const QLoggingCategory &cat) noexcept
0071     {
0072         category = &cat;
0073         // same as:
0074         //  control = cat.isEnabled(Which);
0075         // but without an out-of-line call
0076         if constexpr (Which == QtDebugMsg) {
0077             control = cat.isDebugEnabled();
0078         } else if constexpr (Which == QtInfoMsg) {
0079             control = cat.isInfoEnabled();
0080         } else if constexpr (Which == QtWarningMsg) {
0081             control = cat.isWarningEnabled();
0082         } else if constexpr (Which == QtCriticalMsg) {
0083             control = cat.isCriticalEnabled();
0084         } else if constexpr (Which == QtFatalMsg) {
0085             control = true;
0086         } else {
0087             static_assert(QtPrivate::value_dependent_false<Which>(), "Unknown Qt message type");
0088         }
0089     }
0090     const char *name() const { return category->categoryName(); }
0091     explicit operator bool() const { return Q_UNLIKELY(control); }
0092 };
0093
0094 template <QtMsgType Which> const bool QLoggingCategoryMacroHolder<Which>::IsOutputEnabled = true;
0095 #if defined(QT_NO_DEBUG_OUTPUT)
0096 template <> const bool QLoggingCategoryMacroHolder<QtDebugMsg>::IsOutputEnabled = false;
0097 #endif
0098 #if defined(QT_NO_INFO_OUTPUT)
0099 template <> const bool QLoggingCategoryMacroHolder<QtInfoMsg>::IsOutputEnabled = false;
0100 #endif
0101 #if defined(QT_NO_WARNING_OUTPUT)
0102 template <> const bool QLoggingCategoryMacroHolder<QtWarningMsg>::IsOutputEnabled = false;
0103 #endif
0104 } // unnamed namespace
0105
0106 #define Q_DECLARE_LOGGING_CATEGORY(name) \
0107     const QLoggingCategory &name();
0108
0109 #define Q_DECLARE_EXPORTED_LOGGING_CATEGORY(name, export_macro) \
0110     export_macro Q_DECLARE_LOGGING_CATEGORY(name)
0111
0112 #define Q_LOGGING_CATEGORY(name, ...) \
0113     const QLoggingCategory &name() \
0114     { \
0115         static const QLoggingCategory category(__VA_ARGS__); \
0116         return category; \
0117     }
0118
0119 #define QT_MESSAGE_LOGGER_COMMON(category, level) \
0120     for (QLoggingCategoryMacroHolder<level> qt_category((category)()); qt_category; qt_category.control = false) \
0121         QMessageLogger(QT_MESSAGELOG_FILE, QT_MESSAGELOG_LINE, QT_MESSAGELOG_FUNC, qt_category.name())
0122
0123 #define qCDebug(category, ...) QT_MESSAGE_LOGGER_COMMON(category, QtDebugMsg).debug(__VA_ARGS__)
0124 #define qCInfo(category, ...) QT_MESSAGE_LOGGER_COMMON(category, QtInfoMsg).info(__VA_ARGS__)
0125 #define qCWarning(category, ...) QT_MESSAGE_LOGGER_COMMON(category, QtWarningMsg).warning(__VA_ARGS__)
0126 #define qCCritical(category, ...) QT_MESSAGE_LOGGER_COMMON(category, QtCriticalMsg).critical(__VA_ARGS__)
0127 #define qCFatal(category, ...) QT_MESSAGE_LOGGER_COMMON(category, QtFatalMsg).fatal(__VA_ARGS__)
0128
0129 QT_END_NAMESPACE
0130
0131 #endif // QLOGGINGCATEGORY_H