application.h

C++ class libraries for network-centric, portable applications, integrated perfectly with the C++ St

//
// Application.h
//
// $Id: //poco/1.2/Util/include/Poco/Util/Application.h#2 $
//
// Library: Util
// Package: Application
// Module:  Application
//
// Definition of the Application class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
// 
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//


#ifndef Util_Application_INCLUDED
#define Util_Application_INCLUDED


#include "Poco/Util/Util.h"
#include "Poco/Util/Subsystem.h"
#include "Poco/Util/LayeredConfiguration.h"
#include "Poco/Util/OptionSet.h"
#include "Poco/AutoPtr.h"
#include "Poco/Logger.h"
#include "Poco/Path.h"
#include "Poco/Timestamp.h"
#include "Poco/Timespan.h"
#include <vector>


namespace Poco {
namespace Util {


class OptionSet;


class Util_API Application: public Subsystem
	/// The Application class implements the main subsystem
	/// in a process. The application class is responsible for
	/// initializing all its subsystems.
	///
	/// Subclasses can and should override the following virtual methods:
	///   - initialize() (the one-argument, protected variant)
	///   - uninitialize()
	///   - reinitialize()
	///   - defineOptions()
	///   - handleOption()
	///   - main()
	///
	/// The application's main logic should be implemented in
	/// the main() method.
	///
	/// There may be at most one instance of the Application class
	/// in a process.
	///
	/// The Application class sets a few default properties in 
	/// its configuration (available via the config() method).
	/// These are:
	///   - application.path: the absolute path to application executable
	///   - application.name: the file name of the application executable
	///   - application.baseName: the file name (excluding extension) of the application executable
	///   - application.dir: the path to the directory where the application executable resides
	///   - application.configDir: the path to the directory where the last configuration file loaded with loadConfiguration() was found.
	/// If loadConfiguration() has never been called, application.configDir will be equal to application.dir.
	///
	/// The POCO_APP_MAIN macro can be used to implement main(argc, argv).
	/// If POCO has been built with POCO_WIN32_UTF8, POCO_APP_MAIN supports
	/// Unicode command line arguments.
{
public:
	enum ExitCode
		/// Commonly used exit status codes.
		/// Based on the definitions in the 4.3BSD <sysexits.h> header file.
	{
		EXIT_OK          = 0,  /// successful termination
		EXIT_USAGE	     = 64, /// command line usage error
		EXIT_DATAERR     = 65, /// data format error
		EXIT_NOINPUT     = 66, /// cannot open input
		EXIT_NOUSER      = 67, /// addressee unknown
		EXIT_NOHOST      = 68, /// host name unknown
		EXIT_UNAVAILABLE = 69, /// service unavailable
		EXIT_SOFTWARE    = 70, /// internal software error
		EXIT_OSERR	     = 71, /// system error (e.g., can't fork)
		EXIT_OSFILE      = 72, /// critical OS file missing
		EXIT_CANTCREAT   = 73, /// can't create (user) output file
		EXIT_IOERR       = 74, /// input/output error
		EXIT_TEMPFAIL    = 75, /// temp failure; user is invited to retry
		EXIT_PROTOCOL    = 76, /// remote error in protocol
		EXIT_NOPERM      = 77, /// permission denied
		EXIT_CONFIG      = 78  /// configuration error
	};
	
	Application();
		/// Creates the Application.

	Application(int argc, char* argv[]);
		/// Creates the Application and calls init(argc, argv).

	void addSubsystem(Subsystem* pSubsystem);
		/// Adds a new subsystem to the application. The
		/// application immediately takes ownership of it, so that a
		/// call in the form
		///     Application::instance().addSubsystem(new MySubsystem);
		/// is okay.

	void init(int argc, char* argv[]);
		/// Initializes the application and all registered subsystems,
		/// using the given command line arguments.

#if defined(POCO_WIN32_UTF8)
	void init(int argc, wchar_t* argv[]);
		/// Initializes the application and all registered subsystems,
		/// using the given command line arguments.
		///
		/// This Windows-specific version of init is used for passing
		/// Unicode command line arguments from wmain().
#endif

	void init(const std::vector<std::string>& args);
		/// Initializes the application and all registered subsystems,
		/// using the given command line arguments.

	bool initialized() const;
		/// Returns true iff the application is in initialized state
		/// (that means, has been initialized but not yet uninitialized).

	void setUnixOptions(bool flag);
		/// Specify whether command line option handling is Unix-style
		/// (flag == true; default) or Windows/OpenVMS-style (flag == false).

	int loadConfiguration();
		/// Loads configuration information from a default location.
		///
		/// The configuration file(s) must be located in the same directory
		/// as the executable or a parent directory of it, and must have the 
		/// same base name as the executable, with one of the following extensions:
		/// .properties, .ini or .xml.
		///
		/// The .properties file, if it exists, is loaded first, followed
		/// by the .ini file and the .xml file.
		///
		/// If the application is built in debug mode (the _DEBUG preprocessor
		/// macro is defined) and the base name of the appication executable
		/// ends with a 'd', a config file without the 'd' ending its base name is 
		/// also found.
		/// 
		/// Example: Given the application "SampleAppd.exe", built in debug mode.
		/// Then loadConfiguration() will automatically find a configuration file
		/// named "SampleApp.properties" if it exists and if "SampleAppd.properties"
		/// cannot be found.
		///
		/// Returns the number of configuration files loaded, which may be zero.
		///
		/// This method must not be called before initialize(argc, argv)
		/// has been called.

	void loadConfiguration(const std::string& path);
		/// Loads configuration information from the file specified by
		/// the given path. The file type is determined by the file
		/// extension. The following extensions are supported:
		///   - .properties - properties file (PropertyFileConfiguration)
		///   - .ini        - initialization file (IniFileConfiguration)
		///   - .xml        - XML file (XMLConfiguration)
		///
		/// Extensions are not case sensitive.

	template <class C> C& getSubsystem() const;
		/// Returns a reference to the subsystem of the class
		/// given as template argument.
		///
		/// Throws a NotFoundException if such a subsystem has
		/// not been registered.

	virtual int run();
		/// Runs the application by performing additional initializations
		/// and calling the main() method.

	std::string commandName() const;
		/// Returns the command name used to invoke the application.

	LayeredConfiguration& config() const;
		/// Returns the application's configuration.
		
	Poco::Logger& logger() const;
		/// Returns the application's logger.
		///
		/// Before the logging subsystem has been initialized, the
		/// application's logger is "ApplicationStartup", which is
		/// connected to a ConsoleChannel.
		///
		/// After the logging subsystem has been initialized, which 
		/// usually happens as the first action in Application::initialize(),
		/// the application's logger is the one specified by the
		/// "application.logger" configuration property. If that property
		/// is not specified, the logger is "Application".
		
	const OptionSet& options() const;
		/// Returns the application's option set.

	static Application& instance();
		/// Returns a reference to the Application singleton.
		///
		/// Throws a NullPointerException if no Application instance exists.

	const Poco::Timestamp& startTime() const;
		/// Returns the application start time (UTC).

	Poco::Timespan uptime() const;
		/// Returns the application uptime.
		
	void stopOptionsProcessing();
		/// If called from an option callback, stops all further
		/// options processing.
		///
		/// If called, the following options on the command line
		/// will not be processed, and required options will not
		/// be checked.
		///
		/// This is useful, for example, if an option for displaying
		/// help information has been encountered and no other things
		/// besides displaying help shall be done.

	const char* name() const;

protected:
	void initialize(Application& self);
		/// Initializes the application and all registered subsystems.
		/// Subsystems are always initialized in the exact same order
		/// in which they have been registered.
		///
		/// Overriding implementations must call the base class implementation.
		
	void uninitialize();
		/// Uninitializes the application and all registered subsystems.
		/// Subsystems are always uninitialized in reverse order in which
		/// they have been initialized. 
		///
		/// Overriding implementations must call the base class implementation.

	void reinitialize(Application& self);
		/// Re-nitializes the application and all registered subsystems.
		/// Subsystems are always reinitialized in the exact same order
		/// in which they have been registered.
		///
		/// Overriding implementations must call the base class implementation.

	virtual void defineOptions(OptionSet& options);
		/// Called before command line processing begins.
		/// If a subclass wants to support command line arguments,
		/// it must override this method.
		/// The default implementation does not define any options.
		///
		/// Overriding implementations should call the base class implementation.

	virtual void handleOption(const std::string& name, const std::string& value);
		/// Called when the option with the given name is encountered
		/// during command line arguments processing.
		///
		/// The default implementation does option validation, bindings
		/// and callback handling.
		///
		/// Overriding implementations must call the base class implementation.

	void setLogger(Poco::Logger& logger);
		/// Sets the logger used by the application.

	virtual int main(const std::vector<std::string>& args);
		/// The application's main logic.
		///
		/// Unprocessed command line arguments are passed in args.
		/// Note that all original command line arguments are available
		/// via the properties application.argc and application.argv[<n>].
		///
		/// Returns an exit code which should be one of the values
		/// from the ExitCode enumeration.

	bool findFile(Poco::Path& path) const;
		/// Searches for the file in path in the application directory.
		///
		/// If path is absolute, the method immediately returns true and
		/// leaves path unchanged.
		///
		/// If path is relative, searches for the file in the application
		/// directory and in all subsequent parent directories.
		/// Returns true and stores the absolute path to the file in
		/// path if the file could be found. Returns false and leaves path
		/// unchanged otherwise.

	void init();
		/// Common initialization code.

	~Application();
		/// Destroys the Application and deletes all registered subsystems.

private:
	void setup();
	void setArgs(int argc, char* argv[]);
	void setArgs(const std::vector<std::string>& args);
	void getApplicationPath(Poco::Path& path) const;
	void processOptions();
	bool findAppConfigFile(const std::string& appName, const std::string& extension, Poco::Path& path) const;

	typedef Poco::AutoPtr<Subsystem> SubsystemPtr;
	typedef std::vector<SubsystemPtr> SubsystemVec;
	typedef Poco::AutoPtr<LayeredConfiguration> ConfigPtr;
	typedef std::vector<std::string> ArgVec;
	
	ConfigPtr       _pConfig;
	SubsystemVec    _subsystems;
	bool            _initialized;
	std::string     _command;
	ArgVec          _args;
	OptionSet       _options;
	bool            _unixOptions;
	Poco::Logger*   _pLogger;
	Poco::Timestamp _startTime;
	bool            _stopOptionsProcessing;

	static Application* _pInstance;
	
	friend class LoggingSubsystem;
};


//
// inlines
//
template <class C> C& Application::getSubsystem() const
{
	for (SubsystemVec::const_iterator it = _subsystems.begin(); it != _subsystems.end(); ++it)
	{
		if (dynamic_cast<C*>(*it))
			return **it;
	}
	throw Poco::NotFoundException("The subsystem has not been registered");
}


inline bool Application::initialized() const
{
	return _initialized;
}


inline LayeredConfiguration& Application::config() const
{
	return *const_cast<LayeredConfiguration*>(_pConfig.get());
}


inline Poco::Logger& Application::logger() const
{
	poco_check_ptr (_pLogger);
	return *_pLogger;
}


inline const OptionSet& Application::options() const
{
	return _options;
}


inline Application& Application::instance()
{
	poco_check_ptr (_pInstance);
	return *_pInstance;
}


inline const Poco::Timestamp& Application::startTime() const
{
	return _startTime;
}


inline Poco::Timespan Application::uptime() const
{
	Poco::Timestamp now;
	Poco::Timespan uptime = now - _startTime;
	
	return uptime;
}


} } // namespace Poco::Util


//
// Macro to implement main()
//
#if defined(POCO_WIN32_UTF8)
	#define POCO_APP_MAIN(App) \
	int wmain(int argc, wchar_t** argv)		\
	{										\
		AutoPtr<App> pApp = new App;		\
		try									\
		{									\
			pApp->init(argc, argv);			\
		}									\
		catch (Poco::Exception& exc)		\
		{									\
			pApp->logger().log(exc);		\
			return Application::EXIT_CONFIG;\
		}									\
		return pApp->run();					\
	}
#else
	#define POCO_APP_MAIN(App) \
	int main(int argc, char** argv)			\
	{										\
		AutoPtr<App> pApp = new App;		\
		try									\
		{									\
			pApp->init(argc, argv);			\
		}									\
		catch (Poco::Exception& exc)		\
		{									\
			pApp->logger().log(exc);		\
			return Application::EXIT_CONFIG;\
		}									\
		return pApp->run();					\
	}
#endif


#endif // Util_Application_INCLUDED