qt4log，为博客的附件，包含库文件和头文件

/****************************************************************************** * * This file is part of Log4Qt library. * * Copyright (C) 2007 - 2020 Log4Qt contributors * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * ******************************************************************************/ #ifndef LOG4QT_H #define LOG4QT_H #include "log4qtshared.h" /*! * \page Log4Qt/Log4j * * %Log4Qt is a C++ port of the Apache Software Foundation Log4j package * using the Qt Framework. * * The documentation describes classes and methods that have been added or * changed compared to Log4j. * * The following sections are describing the implementation in more detail: * - \ref Changes "Differences to Log4j" * - \ref Ownership "Object ownership" * - \ref LogLog "Logging within the package" * - \ref Init "Initialization procedure" * - \ref Env "Environment Variables" * - \ref Undocumented "Undocumented functions" * - \ref Assumptions "Assumptions" * */ /*! * \page Changes Differences to Log4j * * The following fundamental differences exist between %Log4Qt and Log4j: * * - As a JAVA package Log4j does not have to manage object ownership and * lifetime in the same way then it is required in C++. For details on * how object ownership is handled see \ref Ownership "Object ownership". * - The package uses itself for its internal logging similar to Log4j 1.3. * For details see \ref LogLog "Logging within the package". * - The configuration using system properties was replaced with a combination * of environment variables and application settings. For details see * \ref Env "Environment Variables". * - Custom levels are not supported. * - Multiple Logger Repositories are not supported * * The following classes have been changed: * * - \ref Log4Qt::AppenderSkeleton "AppenderSkeleton" * - The procedure of checking, if logging is possible, originally used by * \ref Log4Qt::WriterAppender "WriterAppender" was generalised and is used * in \ref Log4Qt::AppenderSkeleton "AppenderSkeleton" and derived classes * (\ref Log4Qt::AppenderSkeleton::checkEntryConditions() "checkEntryConditions()"). * - The \ref Log4Qt::AppenderSkeleton::doAppend() "doAppend()" member function will * check the entry conditions by calling the sub-class specific * \ref Log4Qt::AppenderSkeleton::checkEntryConditions() "checkEntryConditions()". * If successful the sub-class specific * \ref Log4Qt::AppenderSkeleton::append() "append()" function is called. * * - Configurator * - Configure functions return a boolean indicating, if the configuration * was successful. * - Configure errors are accessible over * \ref Log4Qt::ConfiguratorHelper::configureError() * "ConfiguratorHelper::configureError()". * - Watching for configuration file changes is a function performed * centrally by the \ref Log4Qt::ConfiguratorHelper "ConfiguratorHelper". * The class provides Q_SIGNALS to notify on configuration change and errors. * - The class \ref Log4Qt::PropertyConfigurator "PropertyConfigurator" was * extended to be able to read configuration data from a QSettings object. * * - \ref Log4Qt::Level "Level" * - A new value \ref Log4Qt::Level::NULL_INT "Level::NULL_INT" was * introduced to indicate there is no level set. * * - \ref Log4Qt::Logger "Logger" * - The method \ref Log4Qt::Logger::isEnabledFor() "isEnabledFor()" * does also take the repository threshold into account. * - Several overloaded convenience member function are available to log * messages with arguments of different types. * - Two macros, \ref Log4Qt::LOG4QT_DECLARE_STATIC_LOGGER "LOG4QT_DECLARE_STATIC_LOGGER" * and \ref Log4Qt::LOG4QT_DECLARE_QCLASS_LOGGER "LOG4QT_DECLARE_QCLASS_LOGGER", * allows retrieving and caching of a pointer to a logger object. * * - \ref Log4Qt::LogManager "LogManager" * - A QtMessage handler can be installed via * \ref Log4Qt::LogManager::setHandleQtMessages() "setHandleQtMessages()", * to redirect all messages created by calls to qDebug(), qWarning(), * qCritical() and qFatal() to a logger. The logger is named Qt and can be * accessed using \ref Log4Qt::LogManager::qtLogger() "qtLogger()". * - The initialisation procedure is available over a public method * (\ref Log4Qt::LogManager::startup() "startup()"). * - The LogManager provides access to the logger used internally by the * package (\ref Log4Qt::LogManager::logLogger() "logLogger()") and to * its default initialisation procedure * (\ref Log4Qt::LogManager::configureLogLogger() "configureLogLogger()"). * * - \ref Log4Qt::WriterAppender "WriterAppender" * - The class will call \ref Log4Qt::WriterAppender::handleIoErrors() * "handleIoErrors()" after all I/O operations. Sub-classes should * re-implement the function to handle errors. * * - \ref Log4Qt::RollingFileAppender "RollingFileAppender"* * - The class behaves different to the log4/log4cpp implementation * on application restart the existing log files are rolled if * appendFile is set to false to avoid data loss. * * The following classes have been added: * * - An additional appender class, \ref Log4Qt::DebugAppender "DebugAppender", * was added. The class appends logging events to the platform specific debug * output. * - Various helper class have been introduced: * - \ref Log4Qt::ClassLogger "ClassLogger": The class ClassLogger provides * logging for a QObject derived class. * - \ref Log4Qt::ConfiguratorHelper "ConfiguratorHelper": The class * ConfiguratorHelper provides a configuration file watch and last error * for configurator classes. * - \ref Log4Qt::DateTime "DateTime": The class DateTime provides extended * functionality for QDateTime. * - \ref Log4Qt::LogError "LogError": The class LogError represents an error. * - \ref Log4Qt::Factory "Factory": The class Factory provides factories * for Appender, Filter and Layout objects. * - \ref Log4Qt::InitialisationHelper "InitialisationHelper": The class * InitialisationHelper performs static initialisation tasks. * - \ref Log4Qt::PatternFormatter "PatternFormatter": The class * PatternFormatter formats a logging event based on a pattern string. * - \ref Log4Qt::Properties "Properties": The class Properties implements a * JAVA property hash. */ /*! * \page Ownership Object ownership * * In difference to the JAVA Log4j package %Log4Qt must manage ownership and * lifetime of the objects used. This is non trivial as objects are created * and used in different ways. * * In general an object can be created explicitly for example an application * may create Loggers, Appenders and Layouts during creation of a QApplication * object. But they can also be automatically created by the package on * startup using a \ref Log4Qt::PropertyConfigurator "PropertyConfigurator" * configuration file. Objects may also be created the one way and then used * the other. Object may be used by multiple other objects. A Layout for example * may be used by multiple Appenders. Objects are also created from multiple * threads. The creation may happen during static initialisation and the * de