/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 _LOG4CXX_PROPERTY_CONFIGURATOR_H
#define _LOG4CXX_PROPERTY_CONFIGURATOR_H

#include <log4cxx/helpers/object.h>
#include <log4cxx/logstring.h>
#include <log4cxx/spi/configurator.h>
#include <map>

#include <log4cxx/file.h>

namespace LOG4CXX_NS
{
class Logger;
typedef std::shared_ptr<Logger> LoggerPtr;

class Appender;
typedef std::shared_ptr<Appender> AppenderPtr;

namespace helpers
{
class Properties;
}


namespace spi
{
class LoggerFactory;
typedef std::shared_ptr<LoggerFactory> LoggerFactoryPtr;
}

class PropertyWatchdog;
/**
Allows the configuration of log4cxx from an external file.

\anchor PropertyConfigurator_details
The configuration file consists of statements in the format
<code>key=value</code>.
A line beginning with a <code>#</code> or <code>!</code> character
is ignored by %log4cxx (use for a comment).
The syntax of different configuration
elements are discussed below.

The <code>PropertyConfigurator</code> does not handle the
advanced configuration features supported by the
{@link xml::DOMConfigurator DOMConfigurator} such as
support for {@link spi::Filter Filters}, custom
{@link spi::ErrorHandler ErrorHandlers}, nested
appenders such as the {@link AsyncAppender AsyncAppender}, etc.

<h3>Configuring appenders</h3>

%Appender configuration syntax is:
<pre>
# For appender named <i>appenderName</i>, set its class.
# Note: The appender name can contain dots.
log4j.appender.appenderName=fully.qualified.name.of.appender.class

# Set appender specific options.
log4j.appender.appenderName.option1=value1
...
log4j.appender.appenderName.optionN=valueN
</pre>

For each named appender you can configure its {@link Layout Layout}. The
syntax for configuring an appender's layout is:
<pre>
log4j.appender.appenderName.layout=fully.qualified.name.of.layout.class
log4j.appender.appenderName.layout.option1=value1
....
log4j.appender.appenderName.layout.optionN=valueN
</pre>

Refer to the Appender::setOption override of each implemented appender and
Layout::setOption override of each implemented layout
for class specific options.

<h3>Configuring loggers</h3>

The syntax for configuring the root logger is:
<pre>
log4j.rootLogger=[level], appenderName, appenderName, ...
</pre>

This syntax means that an optional <em>level</em> can be
supplied followed by appender names separated by commas.

The level value can consist of the string values OFF, FATAL,
ERROR, WARN, INFO, DEBUG, ALL or a <em>custom level</em> value. A
custom level value can be specified in the form
<code>level#classname</code>.

If a level value is specified, then the root level is set
to the corresponding level.  If no level value is specified,
then the root level remains untouched.

The root logger can be assigned multiple appenders.

Each <i>appenderName</i> (separated by commas) will be added to
the root logger. The named appender is defined using the
appender syntax defined above.

For non-root categories the syntax is almost the same:
<pre>
log4j.logger.logger_name=[level|INHERITED|NULL], appenderName, appenderName,
...
</pre>

The meaning of the optional level value is discussed above
in relation to the root logger. In addition however, the value
INHERITED can be specified meaning that the named logger should
inherit its level from the logger hierarchy.

If no level value is supplied, then the level of the
named logger remains untouched.

By default categories inherit their level from the
hierarchy. However, if you set the level of a logger and later
decide that that logger should inherit its level, then you should
specify INHERITED as the value for the level value. NULL is a
synonym for INHERITED.

Similar to the root logger syntax, each <i>appenderName</i>
(separated by commas) will be attached to the named logger.

See the <a href="concepts.html#appender-additivity">appender
additivity rule</a> in the usage guide for the meaning of the
<code>additivity</code> flag.

<h3>Example</h3>

An example configuration is given below.

<pre>
# Set options for appender named "A1".
# Appender "A1" will be a SyslogAppender
log4j.appender.A1=SyslogAppender

# The syslog daemon resides on www.abc.net
log4j.appender.A1.SyslogHost=www.abc.net

# A1's layout is a PatternLayout, using the conversion pattern
# "%r %-5p %c{2} %M.%L %x - %m%n". Thus, the log output will include
# the relative time since the start of the application in milliseconds, followed by
# the level of the log request, followed by
# the two rightmost components of the logger name, followed by
# the callers method name, followed by the line number,
# the nested disgnostic context and finally the message itself.
# Refer to the documentation of PatternLayout for further information
# on the syntax of the ConversionPattern key.
log4j.appender.A1.layout=PatternLayout
log4j.appender.A1.layout.ConversionPattern=%-4r %-5p %%c{2} %%M.%%L %%x - %%m%%n

# Set options for appender named "A2"
# A2 should be a RollingFileAppender,
# with maximum file size of 10 MB using at most one backup file.
# A2's layout is: date and time (using the ISO8061 date format),
# thread, level, logger name, nested diagnostic context
# and finally the message itself.
log4j.appender.A2=RollingFileAppender
log4j.appender.A2.MaxFileSize=10MB
log4j.appender.A2.MaxBackupIndex=1
log4j.appender.A2.layout=PatternLayout
log4j.appender.A2.layout.ConversionPattern=%%d [%%t] %%p %%c %%x - %%m%%n

# Root logger set to DEBUG using the A2 appender defined above.
log4j.rootLogger=DEBUG, A2

# Logger definitions:
# The SECURITY logger inherits is level from root. However, it's output
# will go to A1 appender defined above. It's additivity is non-cumulative.
log4j.logger.SECURITY=INHERIT, A1
log4j.additivity.SECURITY=false

# Only warnings or above will be logged for the logger "SECURITY.access".
# Output will go to A1.
log4j.logger.SECURITY.access=WARN

# The logger "class.of.the.day" inherits its level from the
# logger hierarchy.  Output will go to the appender's of the root
# logger, A2 in this case.
log4j.logger.class.of.the.day=INHERIT
</pre>

<h3>Dynamic option values</h3>

All option <em>values</em> admit variable substitution. The
syntax of variable substitution is similar to that of Unix
shells. The string between an opening <b>&quot;${&quot;</b> and
closing <b>&quot;}&quot;</b> is interpreted as a key. The value of
the substituted variable can be defined as a system property or in
the configuration file itself. The value of the key is first
searched in the system properties, and if not found there, it is
then searched in the configuration file being parsed.  The
corresponding value replaces the ${variableName} sequence. For
example, if <code>home</code> system property is set to
<code>/home/xyz</code>, then every occurrence of the sequence
<code>${home}</code> will be interpreted as
<code>/home/xyz</code>.

<h3>Repository-wide threshold</h3>

The repository-wide threshold filters logging requests by level
regardless of logger. The syntax is:

<pre>
log4j.threshold=[level]
</pre>

The level value can consist of the string values OFF, FATAL,
ERROR, WARN, INFO, DEBUG, ALL or a <em>custom level</em> value. A
custom level value can be specified in the form
level#classname. By default the repository-wide threshold is set
to the lowest possible value, namely the level <code>ALL</code>.

<h3>Debugging</h3>

It is sometimes useful to see how %log4cxx is reading configuration
files. You can <a href="internal-debugging.html">enable %log4cxx internal logging</a>
by defining the <b>log4j.debug</b> variable in the property file.
<pre>
# Enable internal logging
log4j.debug=true
</pre>

<h3>Logger Factories</h3>

The usage of custom logger factories is discouraged and no longer
documented.

*/
class LOG4CXX_EXPORT PropertyConfigurator :
	virtual public spi::Configurator,
	virtual public helpers::Object
{
	protected:

		/**
		Used internally to keep track of configured appenders.
		*/
		std::map<LogString, AppenderPtr>* registry;

		/**
		Used to create new instances of logger
		*/
		LOG4CXX_DECLARE_PRIVATE_MEMBER(spi::LoggerFactoryPtr, loggerFactory)

	public:
		DECLARE_LOG4CXX_OBJECT(PropertyConfigurator)
		BEGIN_LOG4CXX_CAST_MAP()
#if 15 < LOG4CXX_ABI_VERSION
		LOG4CXX_CAST_ENTRY(PropertyConfigurator)
		LOG4CXX_CAST_ENTRY_CHAIN(spi::Configurator)
#else
		LOG4CXX_CAST_ENTRY(spi::Configurator)
#endif
		END_LOG4CXX_CAST_MAP()

		PropertyConfigurator();
		virtual ~PropertyConfigurator();
		/**
		Read configuration from \c configFileName.
		If \c repository is not provided,
		the spi::LoggerRepository held by LogManager is used.
		<b>The existing configuration is not cleared nor reset.</b>
		If you require a different behavior,
		call {@link spi::LoggerRepository::resetConfiguration resetConfiguration}
		before calling <code>doConfigure</code>.

		@param configFileName The file to parse.
		@param repository Where the Logger instances reside.
		*/
		spi::ConfigurationStatus doConfigure
			( const File&                     configFileName
#if LOG4CXX_ABI_VERSION <= 15
			, spi::LoggerRepositoryPtr        repository
#else
			, const spi::LoggerRepositoryPtr& repository = spi::LoggerRepositoryPtr()
#endif
			) override;

		/**
		Read configuration options from file <code>configFilename</code>.
		Stores Logger instances in the spi::LoggerRepository held by LogManager.
		*/
		static spi::ConfigurationStatus configure(const File& configFilename);

#if LOG4CXX_ABI_VERSION <= 15
		/**
		Like {@link #configureAndWatch(const File& configFilename, long delay)}
		except that the
		default delay as defined by helpers::FileWatchdog#DEFAULT_DELAY
		is used.
		@param configFilename A file in key=value format.
		*/
		static spi::ConfigurationStatus configureAndWatch(const File& configFilename);
#endif
		/**
		Read configuration options from \c configFilename (if it exists).
		Stores Logger instances in the spi::LoggerRepository held by LogManager.
		A thread will be created that periodically checks
		whether \c configFilename has been created or modified.
		A period of log4cxx::helpers::FileWatchdog#DEFAULT_DELAY
		is used if \c delay is not a positive number.
		If a change or file creation is detected,
		then \c configFilename is read to configure Log4cxx.

		The thread will be stopped by a LogManager::shutdown call.

		@param configFilename A file in key=value format.
		@param delay The delay in milliseconds to wait between each check.
		*/
		static spi::ConfigurationStatus configureAndWatch(const File& configFilename,
			long delay = 0);

		/**
		Read configuration options from <code>properties</code>.
		Stores Logger instances in the spi::LoggerRepository held by LogManager.
		See the \ref PropertyConfigurator_details "detailed description"
		for the expected format.
		*/
		static spi::ConfigurationStatus configure(helpers::Properties& properties);

		/**
		Read configuration options from <code>properties</code>.
		See the \ref PropertyConfigurator_details "detailed description"
		for the expected format.
		*/
		spi::ConfigurationStatus doConfigure(helpers::Properties& properties,
			spi::LoggerRepositoryPtr hierarchy);

		// --------------------------------------------------------------------------
		// Internal stuff
		// --------------------------------------------------------------------------
	protected:
		/**
		Check the provided <code>Properties</code> object for a LoggerFactory
		entry specified by *log4j.loggerFactory*.  If such an entry
		exists, an attempt is made to create an instance using the default
		constructor.  This instance is used for subsequent Logger creations
		within this configurator.
		@see #parseCatsAndRenderers
		*/
		void configureLoggerFactory(helpers::Properties& props);

		void configureRootLogger(helpers::Properties& props,
			spi::LoggerRepositoryPtr& hierarchy);

		/**
		Parse non-root elements, such non-root categories and renderers.
		*/
		void parseCatsAndRenderers(helpers::Properties& props,
			spi::LoggerRepositoryPtr& hierarchy);

		/**
		Parse the additivity option for a non-root logger.
		*/
		bool parseAdditivityForLogger(helpers::Properties& props,
			LoggerPtr& cat, const LogString& loggerName);

		/**
		This method must work for the root logger as well.
		*/
		void parseLogger(
			helpers::Properties& props, LoggerPtr& logger,
			const LogString& optionKey, const LogString& loggerName,
			const LogString& value, bool additivity);

		AppenderPtr parseAppender(
			helpers::Properties& props, const LogString& appenderName);

		void registryPut(const AppenderPtr& appender);
		AppenderPtr registryGet(const LogString& name);

	private:
		PropertyConfigurator(const PropertyConfigurator&);
		PropertyConfigurator& operator=(const PropertyConfigurator&);
}; // class PropertyConfigurator
}  // namespace log4cxx


#endif //_LOG4CXX_PROPERTY_CONFIGURATOR_H
