cpp_example_userio.cpp

/**
 * @file
 *
 * @brief This examples show how Elektra's KDBException can be changed in a way so that it has user defined output.
 *
 *
 * It works -- because of binary compatibility -- if only the receiver
 * of the message (where it is catched) redefines the IO functions
 * printError and printWarnings. They need to be defined with the
 * same signature and in either global or kdb namespace.
 *
 * The output operators of Key and KeySet can be redefined without any
 * macro by simply not including \<keyio.hpp\> and \<keysetio.hpp\>.
 *
 * @copyright BSD License (see doc/COPYING or http://www.libelektra.org)
 */

#define USER_DEFINED_IO

#include <iomanip>
#include <iostream>

#include <key.hpp>

inline std::ostream & printError (std::ostream & os, kdb::Key const & error)
{
	os << "User defined IO (errors)" << std::endl;

	try
	{
		if (!error.getMeta<const kdb::Key> ("error"))
		{
			// no error available
			return os;
		}

		os << "Error number " << error.getMeta<std::string> ("error/number") << " occurred!" << std::endl;
		os << "Description: " << error.getMeta<std::string> ("error/description") << std::endl;
		os << "Ingroup: " << error.getMeta<std::string> ("error/ingroup") << std::endl;
		os << "Module: " << error.getMeta<std::string> ("error/module") << std::endl;
		os << "At: " << error.getMeta<std::string> ("error/file") << ":" << error.getMeta<std::string> ("error/line") << std::endl;
		os << "Reason: " << error.getMeta<std::string> ("error/reason") << std::endl;
		os << "Mountpoint: " << error.getMeta<std::string> ("error/mountpoint") << std::endl;
		os << "Configfile: " << error.getMeta<std::string> ("error/configfile") << std::endl;
	}
	catch (kdb::KeyTypeConversion const & e)
	{
		os << "Error meta data is not set correctly by a plugin" << std::endl;
	}

	return os;
}

inline std::ostream & printWarnings (std::ostream & os, kdb::Key const & error)
{
	os << "User defined IO (warnings)" << std::endl;

	try
	{
		if (!error.getMeta<const kdb::Key> ("warnings"))
		{
			// no warnings were issued
			return os;
		}

		int nr = error.getMeta<int> ("warnings");
		if (!nr)
		{
			os << "1 Warning was issued:" << std::endl;
		}
		else
		{
			os << nr + 1 << " Warnings were issued:" << std::endl;
		}

		for (int i = 0; i <= nr; i++)
		{
			std::ostringstream name;
			name << "warnings/#" << std::setfill ('0') << std::setw (2) << i;
			// os << "\t" << name.str() << ": " << error.getMeta<std::string>(name.str()) << std::endl;
			os << "\tWarning number: " << error.getMeta<std::string> (name.str () + "/number") << std::endl;
			os << "\tDescription: " << error.getMeta<std::string> (name.str () + "/description") << std::endl;
			os << "\tIngroup: " << error.getMeta<std::string> (name.str () + "/ingroup") << std::endl;
			os << "\tModule: " << error.getMeta<std::string> (name.str () + "/module") << std::endl;
			os << "\tAt: " << error.getMeta<std::string> (name.str () + "/file") << ":"
			   << error.getMeta<std::string> (name.str () + "/line") << std::endl;
			os << "\tReason: " << error.getMeta<std::string> (name.str () + "/reason") << std::endl;
			os << "\tMountpoint: " << error.getMeta<std::string> (name.str () + "/mountpoint") << std::endl;
			os << "\tConfigfile: " << error.getMeta<std::string> (name.str () + "/configfile") << std::endl;
		}
	}
	catch (kdb::KeyTypeConversion const & e)
	{
		os << "Warnings meta data not set correctly by a plugin" << std::endl;
	}

	return os;
}

#include <kdb.hpp>

#include <kdbio.hpp>
#include <keyio.hpp>
#include <keysetio.hpp>

int main ()
{
	kdb::Key k ("user/sw/MyApp", KEY_END);
	std::cout << k << std::endl;

	kdb::KeySet ks;
	ks.append (k);
	std::cout << ks;

	try
	{
		kdb::KDB kdb (k);
		kdb.get (ks, k);

		std::cout << ks;

		kdb.set (ks, k);
		kdb.close (k);
		printWarnings (std::cout, k);
	}
	catch (kdb::KDBException const & e)
	{
		std::cout << e.what (); // will print user defined IO
	}
}