query-focus.cpp

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/*
  QueryFocus  -  management of current scope within the Session

  Copyright (C)         Lumiera.org
    2009,               Hermann Vosseler <Ichthyostega@web.de>

  This program is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License as
  published by the Free Software Foundation; either version 2 of
  the License, or (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

* *****************************************************/


#include "steam/mobject/session/query-focus.hpp"
#include "steam/mobject/mobject.hpp"
#include "lib/format-string.hpp"

using util::_Fmt;

namespace steam {
namespace mobject {
namespace session {
  
  
  
  QueryFocus::QueryFocus()
    : focus_( & currPath())
    { }
  
  
  QueryFocus::QueryFocus(ScopePath& path_to_attach)
    : focus_( &path_to_attach)
    { }
  
  
  ScopePath&
  QueryFocus::currPath()
  {
    return ScopeLocator::instance().currPath();
  }
  
  
  QueryFocus&
  QueryFocus::reset ()
  {
    REQUIRE (focus_);
    focus_->clear();
    return *this;
  }
  
  
  
  
  
  namespace {// error check shortcut....
    
    using lumiera::error::Invalid;
    
    void
    ___check_validTaget (Scope const& target)
    {
      if (!target.isValid())
        throw Invalid{"Invalid target location for QueryFocus"
                     , LERR_(INVALID_SCOPE)};             
    }
  }//(End) shortcut
  
  
  
  QueryFocus&
  QueryFocus::shift (Scope const& container)
  {
    ___check_validTaget (container);
    
    REQUIRE (focus_);
    focus_->navigate (container);
    return *this;
  }
  
  
  QueryFocus
  QueryFocus::push (Scope const& otherContainer)
  {
    ___check_validTaget (otherContainer);
    
    QueryFocus newFocus (ScopeLocator::instance().pushPath());
    newFocus.shift (otherContainer);
    return newFocus;
  }
  
  
  QueryFocus
  QueryFocus::push ()
  {
    Scope currentLocation (ScopeLocator::instance().currPath().getLeaf());
    ENSURE (currentLocation.isValid());
    
    QueryFocus newFocus (ScopeLocator::instance().pushPath());
    newFocus.shift (currentLocation);
    return newFocus;
  }
  
  
  
  QueryFocus&
  QueryFocus::pop()
  {
    focus_ = 0;
    focus_ = & currPath();
    
    return *this;
  }
  
  
  
  QueryFocus::operator string()  const 
  {
    static _Fmt display("Focus(%d)--->%s");
    return display % ScopeLocator::instance().stackSize()
                   % *focus_;
  }
  
  
  
}}} // namespace steam::mobject::session