Files
pilotclient/src/blackmisc/logmessage.h

192 lines
8.6 KiB
C++

/* Copyright (C) 2014
* Swift Project Community / Contributors
*
* This file is part of Swift Project. It is subject to the license terms in the LICENSE file found in the top-level
* directory of this distribution and at http://www.swift-project.org/license.html. No part of swift project,
* including this file, may be copied, modified, propagated, or distributed except according to the terms
* contained in the LICENSE file.
*/
#ifndef BLACKMISC_LOGMESSAGE_H
#define BLACKMISC_LOGMESSAGE_H
//! \file
#include "blackmiscexport.h"
#include "statusmessagelist.h"
#include "statusmessage.h"
#include "logcategorylist.h"
#include "index_sequence.h"
#include <QDebug>
#include <QLoggingCategory>
#include <QList>
#include <type_traits>
namespace BlackMisc
{
/*!
* Trait to detect whether T contains a member toQString.
*/
template <typename T>
class HasToQString
{
// http://en.wikibooks.org/wiki/More_C++_Idioms/Member_Detector
struct Fallback { int toQString; };
template <int Fallback:: *> struct int_t { typedef int type; };
template <typename U, bool = std::is_class<U>::value> struct Derived : public U, public Fallback {};
template <typename U> struct Derived<U, false> : public Fallback {};
template <typename U> static char test(typename int_t<&Derived<U>::toQString>::type);
template <typename U> static int test(...);
public:
//! True if T contains a member toQString.
static const bool value = sizeof(test<T>(0)) > 1;
};
/*!
* Helper with static methods for dealing with metadata embedded in log message category strings.
*
* There are certain aspects of log messages which cannot be represented in Qt's native log message machinery.
* Therefore we are forced to use a special encoding of the message category string to encode these aspects.
*
* An encoded category string consists of a plain category string with zero or more flag strings appended.
* The plain category and the flags are all separated by forward-slash characters ('/').
*
* There are currently two flags:
* \li \c "debug" Qt only has 3 ordinary severities (debug, warning, critical), so we use QtMsgDebug for both
* debug and info messages, and we use this flag to distinguish between them.
* \li \c "redundant" To avoid handling the same message twice, this flag identifies a message which has already
* been directly returned as the return value of the method which generated it.
*/
class BLACKMISC_EXPORT CLogMessageHelper
{
public:
//! Deleted constructor.
CLogMessageHelper() = delete;
//! Returns an encoded category string with the debug flag appended.
static QString addDebugFlag(const QString &category);
//! Returns an encoded category string with the redundant flag appended.
static QString addRedundantFlag(const QString &category);
//! Strips all flags from an encoded category string, returning only the plain category string.
static QString stripFlags(const QString &category);
//! Returns true if the given encoded category string has the debug flag.
static bool hasDebugFlag(const QString &category);
//! Returns true if the given encoded category string has the redundant flag.
static bool hasRedundantFlag(const QString &category);
};
/*!
* Class for emitting a log message. Works similar to the qDebug, qWarning, qCritical family of functions.
*
* The member functions debug, info, warning, error, and the stream operators all return a reference to <tt>*this</tt>,
* so they can be chained together.
*
* The categories are arbitrary string tags which can be attached to the message to categorize it.
* A message can have more than one category. The categories can be used for filtering by message handlers.
*/
class BLACKMISC_EXPORT CLogMessage
{
public:
//! Construct a message with the "uncategorized" category.
CLogMessage() {}
//! Constructor taking filename, line number, and function name, for uncategorized verbose debug messages.
CLogMessage(const char *file, int line, const char *function) : m_logger(file, line, function) {}
//! Construct a message with some specific category.
CLogMessage(const CLogCategory &category) : m_categories({ category }) {}
//! Construct a message with some specific categories.
CLogMessage(const CLogCategoryList &categories) : m_categories(categories) {}
//! Construct a message with some specific categories.
CLogMessage(const CLogCategoryList &categories, const CLogCategory &extra) : CLogMessage(categories) { m_categories.push_back(extra); }
//! Construct a message with some specific categories.
CLogMessage(const CLogCategoryList &categories, const CLogCategoryList &extra) : CLogMessage(categories) { m_categories.push_back(extra); }
//! Destructor. This actually emits the message.
~CLogMessage();
//! Convert to CStatusMessage for returning the message directly from the function which generated it.
operator CStatusMessage();
//! Convert to CVariant for returning the message directly from the function which generated it.
operator CVariant();
//! Set the severity to debug.
CLogMessage &debug();
//! Set the severity to info, providing a format string.
CLogMessage &info(QString format);
//! Set the severity to warning, providing a format string.
CLogMessage &warning(QString format);
//! Set the severity to error, providing a format string.
CLogMessage &error(QString format);
//! Set the severity to info, providing a format string, and adding the validation category.
CLogMessage &validationInfo(QString format);
//! Set the severity to warning, providing a format string, and adding the validation category.
CLogMessage &validationWarning(QString format);
//! Set the severity to error, providing a format string, and adding the validation category.
CLogMessage &validationError(QString format);
//! Streaming operators.
//! \details If the format string is empty, the message will consist of all streamed values separated by spaces.
//! Otherwise, the streamed values will replace the place markers %1, %2, %3... in the format string.
//! \see QString::arg
//! @{
CLogMessage &operator <<(const QString &v) { return arg(v); }
CLogMessage &operator <<(int v) { return arg(QString::number(v)); }
CLogMessage &operator <<(uint v) { return arg(QString::number(v)); }
CLogMessage &operator <<(long v) { return arg(QString::number(v)); }
CLogMessage &operator <<(ulong v) { return arg(QString::number(v)); }
CLogMessage &operator <<(qlonglong v) { return arg(QString::number(v)); }
CLogMessage &operator <<(qulonglong v) { return arg(QString::number(v)); }
CLogMessage &operator <<(short v) { return arg(QString::number(v)); }
CLogMessage &operator <<(ushort v) { return arg(QString::number(v)); }
CLogMessage &operator <<(QChar v) { return arg(v); }
CLogMessage &operator <<(char v) { return arg(QChar(v)); }
CLogMessage &operator <<(double v) { return arg(QString::number(v)); }
template <class T, class = typename std::enable_if<HasToQString<T>::value>::type>
CLogMessage &operator <<(const T &v) { return arg(v.toQString()); }
//! @}
//! Sends a verbatim, preformatted message to the log.
static void preformatted(const CStatusMessage &statusMessage);
//! Sends a list of verbatim, preformatted messages to the log.
static void preformatted(const CStatusMessageList &statusMessages);
private:
QMessageLogger m_logger;
CStatusMessage::StatusSeverity m_severity = CStatusMessage::SeverityDebug;
CLogCategoryList m_categories = CLogCategoryList { CLogCategory::uncategorized() };
QString m_message;
QStringList m_args;
bool m_redundant = false;
CLogMessage &arg(QString value) { m_args.push_back(value); return *this; }
QString message() const;
QByteArray qtCategory() const;
QDebug ostream(const QByteArray &category) const;
};
}
/*!
* Convenience macro to construct a CLogMessage with the filename, line number, and function name,
* for verbose debug messages.
*/
#define BLACK_LOG (BlackMisc::CLogMessage { __FILE__, __LINE__, Q_FUNC_INFO })
#endif