// $Id$
//
// Copyright (C) 2007
// Fraunhofer Institute for Open Communication Systems (FOKUS)
//
// The contents of this file are subject to the Fraunhofer FOKUS Public License
// Version 1.0 (the "License"); you may not use this file except in compliance
// with the License. You may obtain a copy of the License at 
// http://senf.berlios.de/license.html
//
// The Fraunhofer FOKUS Public License Version 1.0 is based on, 
// but modifies the Mozilla Public License Version 1.1.
// See the full license text for the amendments.
//
// Software distributed under the License is distributed on an "AS IS" basis, 
// WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License 
// for the specific language governing rights and limitations under the License.
//
// The Original Code is Fraunhofer FOKUS code.
//
// The Initial Developer of the Original Code is Fraunhofer-Gesellschaft e.V. 
// (registered association), Hansastraße 27 c, 80686 Munich, Germany.
// All Rights Reserved.
//
// Contributor(s):
//   Stefan Bund <g0dil@berlios.de>

/** \file
    \brief Definitions internal header */

#ifndef IH_SENF_Utils_Logger_Definitions_
#define IH_SENF_Utils_Logger_Definitions_ 1

// Custom includes

//-/////////////////////////////////////////////////////////////////////////////////////////////////

// Implementation details concerning SENF_LOG_CLASS_AREA
//
// The SENF_LOG_CLASS_AREA statement shall declare the containing class as it's own default area. Of
// course, we cannot make the containing class into an area. Therefore we need to trick around a bit:
//
// We begin by defining an area SENFLogArea with in the class. This area however is hacked, so that
// it's name() member will return the name of the containing class (which is simple: just cut of the
// last couple of characters of the name since the name will always end in '::SENFLogArea').
//
// This however does not allow the use of the containing class as an area. There are several places
// which need to be adjusted to allow using the containing class as an area: The logging statements
// (SENF_LOG), the compile time configuration via SENF_LOG_CONF and the runtime configuration via
// route statements.
//
// Lets begin with the compile time configuration. The compile time configuration is done using
// specialization of the senf::log::detail::Config template. This doesn't care, what the area
// template argument really is. Therefore, compile-time configuration just uses the containing class
// as is. So we need to make sure, that the logging statements use the containing class when
// checking the compile-time limit whereas they need to use the nested SENFLogArea when calling the
// targets.
//
// So let's look at the logging statements. The central logic for parsing the logging parameters is
// in SENF_LOG_MERGE_PARAMETERS in Parameters.ih. Here we have a special case which detects classes
// with a SENFLogArea member and then set's things up correctly: It uses the containing class for
// compile time checking (this is, what 'area_base' typedef is for) while using the nested
// SENFLogArea for routing (this is, what the 'area' typedef is for).
//
// So the last thing which needs to be adjusted is the routing which is part of the Target
// class. Here for each template taking an area as an argument we really provide TWO templates, one
// taking the area directly, the other checking for a nested SENFLogArea member. We can
// differentiate these overloads using boost::enable_if and friends.
//
// This setup makes a class with SENF_LOG_CLASS_AREA() look like an ordinary area even though the
// implementation is somewhat different.

#define SENF_LOG_DEFINE_AREA_I(area, decls)                                                       \
    struct area                                                                                   \
        : public senf::log::detail::AreaBase, public senf::singleton<area>                        \
    {                                                                                             \
        static std::string name() { return instance().v_name(); }                                 \
        using senf::singleton<area>::instance;                                                    \
        decls                                                                                     \
    private:                                                                                      \
        area() { init(); }                                                                        \
        friend class senf::singleton<area>;                                                       \
    }

namespace senf {
namespace log {
namespace detail {

    /// Internal: Alias base class
    struct AliasBase {};

}}}

//-/////////////////////////////////////////////////////////////////////////////////////////////////
#endif


// Local Variables:
// mode: c++
// fill-column: 100
// comment-column: 40
// c-file-style: "senf"
// indent-tabs-mode: nil
// ispell-local-dictionary: "american"
// compile-command: "scons -u test"
// End: