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Please review the following information to ** ensure the GNU General Public License version 3.0 requirements will be ** met: http://www.gnu.org/copyleft/gpl.html. ** ** ** $QT_END_LICENSE$ ** ****************************************************************************/ #include "qloggingcategory.h" #include "qloggingcategory_p.h" #include "qloggingregistry_p.h" QT_BEGIN_NAMESPACE const char qtDefaultCategoryName[] = "default"; Q_GLOBAL_STATIC_WITH_ARGS(QLoggingCategory, qtDefaultCategory, (qtDefaultCategoryName)) /*! \class QLoggingCategory \inmodule QtCore \since 5.2 \brief A category, or 'area' in the logging infrastructure. QLoggingCategory represents a certain logging category - identified by a string - at runtime. Whether a category should be actually logged or not can be checked with the \l isEnabled() methods. \section1 Creating category objects Qt provides the \l Q_LOGGING_CATEGORY(), Q_DECLARE_LOGGING_CATEGORY() macros to conveniently create static QLoggingCategory objects on the heap: \snippet qloggingcategory/main.cpp 1 \section1 Checking category configuration QLoggingCategory provides two isEnabled methods, a template one and a non-template one, for checking whether the current category is enabled. The template version checks for the most common case that no special rules are applied in inline code, and should be preferred: \snippet qloggingcategory/main.cpp 2 Note that qCDebug() prevents arguments from being evaluated if the string won't print, so calling isEnabled explicitly is not needed: \l isEnabled(). \snippet qloggingcategory/main.cpp 3 \section1 Default configuration In the default configuration \l isEnabled() will return true for all \l QtMsgType types except QtDebugMsg: QtDebugMsg is only active by default for the \c "default" category. \section1 Changing configuration The default configuration can be changed by calling \l setEnabled(). However, this only affects the current category object, not e.g. another object for the same category name. Use either \l setFilterRules() or \l installFilter() to configure categories globally. */ /*! Constructs a QLoggingCategory object with the provided \a category name. The object becomes the local identifier for the category. If \a category is \c{0}, the category name is changed to \c{"default"}. */ QLoggingCategory::QLoggingCategory(const char *category) : name(0), enabledDebug(false), enabledWarning(true), enabledCritical(true), enabledTrace(false) { bool isDefaultCategory = (category == 0) || (strcmp(category, qtDefaultCategoryName) == 0); if (isDefaultCategory) { // normalize default category names, so that we can just do // pointer comparison in QLoggingRegistry::updateCategory name = qtDefaultCategoryName; enabledDebug = true; } else { name = category; } if (QLoggingRegistry *reg = QLoggingRegistry::instance()) reg->registerCategory(this); } /*! Destructs a QLoggingCategory object */ QLoggingCategory::~QLoggingCategory() { if (QLoggingRegistry *reg = QLoggingRegistry::instance()) reg->unregisterCategory(this); } /*! \fn const char *QLoggingCategory::categoryName() const Returns the name of the category. */ /*! \fn bool QLoggingCategory::isEnabled() const Returns true if a message of the template \c QtMsgType argument should be shown. Returns false otherwise. \note The qCDebug, qCWarning, qCCritical macros already do this check before executing any code. However, calling this method may be useful to avoid expensive generation of data that is only used for debug output. */ /*! Returns true if a message of type \a msgtype for the category should be shown. Returns false otherwise. \note The templated, inline version of this method, \l isEnabled(), is optimized for the common case that no configuration is set, and should generally be preferred. */ bool QLoggingCategory::isEnabled(QtMsgType msgtype) const { switch (msgtype) { case QtDebugMsg: return enabledDebug; case QtWarningMsg: return enabledWarning; case QtCriticalMsg: return enabledCritical; case QtTraceMsg: return enabledTrace; case QtFatalMsg: return true; default: break; } return false; } /*! Changes the type \a type for the category to \a enable. Changes only affect the current QLoggingCategory object, and won't change e.g. the settings of another objects for the same category name. \note QtFatalMsg cannot be changed. It will always return true. Example: \snippet qtracer/ftracer.cpp 5 */ void QLoggingCategory::setEnabled(QtMsgType type, bool enable) { switch (type) { case QtDebugMsg: enabledDebug = enable; break; case QtWarningMsg: enabledWarning = enable; break; case QtCriticalMsg: enabledCritical = enable; break; case QtTraceMsg: enabledTrace = enable; break; case QtFatalMsg: default: break; } } /*! \fn QLoggingCategory &QLoggingCategory::operator()() Returns the object itself. This allows both a QLoggingCategory variable, and a factory method returning a QLoggingCategory, to be used in qCDebug(), qCWarning(), qCCritial() macros. */ /*! Returns the category "default" that is used e.g. by qDebug(), qWarning(), qCritical(), qFatal(). */ QLoggingCategory &QLoggingCategory::defaultCategory() { return *qtDefaultCategory(); } /*! \typedef QLoggingCategory::CategoryFilter This is a typedef for a pointer to a function with the following signature: \snippet qloggingcategory/main.cpp 20 A function with this signature can be installed with \l installFilter(). */ /*! Installs a function \a filter that is used to determine which categories and message types should be enabled. Returns a pointer to the previous installed filter. Every QLoggingCategory object created is passed to the filter, and the filter is free to change the respective category configuration with \l setEnabled(). An alternative way of configuring the default filter is via \l setFilterRules(). */ QLoggingCategory::CategoryFilter QLoggingCategory::installFilter(QLoggingCategory::CategoryFilter filter) { return QLoggingRegistry::instance()->installFilter(filter); } /*! Configures which categories and message types should be enabled through a a set of \a rules. Each line in \a rules must have the format \code [.] = true|false \endcode where \c is the name of the category, potentially with \c{*} as a wildcard symbol at the start and/or the end. The optional \c must be either \c debug, \c warning, or \c critical. The rules might be ignored if a custom category filter is installed with \l installFilter(). */ void QLoggingCategory::setFilterRules(const QString &rules) { QLoggingRegistry::instance()->rulesParser.setRules(rules); } /*! \macro qCDebug(category) \relates QLoggingCategory \since 5.2 Returns an output stream for debug messages in the logging category \a category. The macro expands to code that first checks whether \l QLoggingCategory::isEnabled() evaluates for debug output to \c{true}. If so, the stream arguments are processed and sent to the message handler. Example: \snippet qloggingcategory/main.cpp 10 \note Arguments are not processed if debug output for the category is not enabled, so do not rely on any side effects. \sa qDebug() */ /*! \macro qCWarning(category) \relates QLoggingCategory \since 5.2 Returns an output stream for warning messages in the logging category \a category. The macro expands to code that first checks whether \l QLoggingCategory::isEnabled() evaluates for warning output to \c{true}. If so, the stream arguments are processed and sent to the message handler. Example: \snippet qloggingcategory/main.cpp 11 \note Arguments are not processed if warning output for the category is not enabled, so do not rely on any side effects. \sa qWarning() */ /*! \macro qCCritical(category) \relates QLoggingCategory \since 5.2 Returns an output stream for critical messages in the logging category \a category. The macro expands to code that first checks whether \l QLoggingCategory::isEnabled() evaluates for critical output to \c{true}. If so, the stream arguments are processed and sent to the message handler. Example: \snippet qloggingcategory/main.cpp 12 \note Arguments are not processed if critical output for the category is not enabled, so do not rely on any side effects. \sa qCritical() */ /*! \relates QLoggingCategory \macro qCTrace(category) \since 5.2 Returns an output stream for trace messages in the logging category \a category. The macro expands to code that first checks whether \l QLoggingCategory::isEnabled() evaluates for trace output to \c{true}. If so, the stream arguments are processed and sent to the tracers registered with the category. \note Arguments are not processed if trace output for the category is not enabled, so do not rely on any side effects. Example: \snippet qtracer/ftracer.cpp 6 \sa qCTraceGuard() */ /*! \relates QLoggingCategory \macro qCTraceGuard(category) \since 5.2 The macro expands to code that creates a guard object with automatic storage. The guard constructor checks whether \l QLoggingCategory::isEnabled() evaluates for trace output to \c{true}. If so, the stream arguments are processed and the \c{start()} functions of the tracers registered with the \a category are called. The guard destructor also checks whether the category is enabled for tracing and if so, the \c{end()} functions of the tracers registered with the \a category are called. \note Arguments are always processed, even if trace output for the category is disabled. They will, however, in that case not be passed to the \c{record()} functions of the registered tracers. Example: \snippet qtracer/ftracer.cpp 4 \sa qCTrace() */ /*! \macro Q_DECLARE_LOGGING_CATEGORY(name) \relates QLoggingCategory \since 5.2 Declares a logging category \a name. The macro can be used to declare a common logging category shared in different parts of the program. This macro must be used outside of a class or method. */ /*! \macro Q_LOGGING_CATEGORY(name, string) \relates QLoggingCategory \since 5.2 Defines a logging category \a name, and makes it configurable under the \a string identifier. Only one translation unit in a library or executable can define a category with a specific name. This macro must be used outside of a class or method. */ /*! \class QTracer \inmodule QtCore \since 5.2 \brief The QTracer class provides an interface for handling trace events associated with a logging category. \c QTracer objects are registered with logging categories. Multiple \c QTracer objects can be registered with the same category, and the same \c QTracer object can be registered with different categories. If code containing \c qCTrace is executed, and the associated logging category is enabled for tracing, all \c QTracer objects that are registered with the category are notified. \c QTracer objects */ /*! \fn QTracer::QTracer() Constructs a tracer object. Example: \snippet qtracer/ftracer.cpp 2 */ /*! \fn QTracer::~QTracer() Destroys the tracer object. */ /*! Registers this tracer for the \a category. The tracer will later be notified of messages of type \c QtTraceMsg, as long as that message type is enabled in the category. Example: \snippet qtracer/ftracer.cpp 1 \codeline \snippet qtracer/ftracer.cpp 7 */ void QTracer::addToCategory(QLoggingCategory &category) { category.tracers.append(this); } /*! \fn void QTracer::start() This function is invoked when a tracing activity starts, typically from the constructor of a \c QTraceGuard object defined by \c qCTrace() or \c qCTraceGuard(). The base implementation does nothing. \c QTracer subclasses are advised to override it if needed. \sa qCTrace(), qCTraceGuard() */ /*! \fn void QTracer::end() This function is invoked when a tracing activity ends, typically from the destructor of a \c QTraceGuard object defined by \c qCTrace() or \c qCTraceGuard(). The base implementation does nothing. It is common for \c QTracer subclasses to override it to perform flushing of collected data. \sa qCTrace(), qCTraceGuard() */ /*! \fn void QTracer::record(int data) This function is invoked during a tracing activity to pass integer \a data to the \c QTracer object. Example: \snippet qtracer/ftracer.cpp 3 */ /*! \fn void QTracer::record(const char *data) This function is invoked during a tracing activity to pass string \a data to the \c QTracer object. */ /*! \fn void QTracer::record(const QVariant &data) This function is invoked during a tracing activity to pass abitrary (non-integer, non-string) \a data to the \c QTracer object. */ /*! \class QTraceGuard \since 5.2 \inmodule QtCore \brief The QTraceGuard class facilitates notifications to \c QTracer objects. \c QTraceGuard objects are typically implicitly created on the stack when using the \c qCTrace or \c qCTraceGuard macros and are associated to a \c QLoggingCategory. The constructor of a \c QTraceGuard objects checks whether its associated category is enabled, and if so, informs all \c QTracer objects registered with the category that a tracing activity starts. The destructor of a \c QTraceGuard objects checks whether its associated category is enabled, and if so, informs all \c QTracer objects registered with the category that a tracing activity ended. A \c QTraceGuard object created by \c qCTrace will be destroyed at the end of the full expression, a guard created by \c qCTraceGuard at the end of the block containing the macro. During the lifetime of a QTraceGuard object, its \c operator<<() can be used to pass additional data to the active tracers. The fast path handles only \c int and \c{const char *} data, but it is possible to use arbitrary values wrapped in \c QVariants. \sa QTracer */ /*! \fn QTraceGuard::QTraceGuard(QLoggingCategory &category) \internal Constructs a trace guard object relaying to \a category. */ /*! \fn QTraceGuard::~QTraceGuard() \internal Destroys the trace guard object. */ /*! \internal Calls \c start() on all registered tracers. */ void QTraceGuard::start() { QLoggingCategory::Tracers &tracers = target->tracers; for (int i = tracers.size(); --i >= 0; ) tracers.at(i)->start(); } /*! \internal Calls \c end() on all registered tracers. */ void QTraceGuard::end() { QLoggingCategory::Tracers &tracers = target->tracers; for (int i = tracers.size(); --i >= 0; ) tracers.at(i)->end(); } /*! \internal This function is called for int parameters passed to the qCTrace stream. */ QTraceGuard &QTraceGuard::operator<<(int msg) { QLoggingCategory::Tracers &tracers = target->tracers; for (int i = tracers.size(); --i >= 0; ) tracers.at(i)->record(msg); return *this; } /*! \internal This function is called for string parameters passed to the qCTrace stream. */ QTraceGuard &QTraceGuard::operator<<(const char *msg) { QLoggingCategory::Tracers &tracers = target->tracers; for (int i = tracers.size(); --i >= 0; ) tracers.at(i)->record(msg); return *this; } /*! \internal This function is called for QVariant parameters passed to the qCTrace stream. */ QTraceGuard &QTraceGuard::operator<<(const QVariant &msg) { QLoggingCategory::Tracers &tracers = target->tracers; for (int i = tracers.size(); --i >= 0; ) tracers.at(i)->record(msg); return *this; } QT_END_NAMESPACE