RoutedForwarding.cc

// Copyright 2008 Michael Marsh, University of Maryland.
//
// This file is part of pydtn.
//
// pydtn 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 3 of the License, or
// (at your option) any later version.
//
// pydtn 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 pydtn.  If not, see <http://www.gnu.org/licenses/>.
//
// The views and conclusions contained in the software and documentation
// are those of the authors and should not be interpreted as representing
// official policies, either expressed or implied, of the University
// of Maryland.
//
// pydtn extends and embeds the Python interpreter, which is
// Copyright 2001-2006 Python Software Foundation, All Rights Reserved,
// and is released under the PSF License Agreement.
//
// RANLUX random number generation uses the Boost library,
// Copyright 1994-2006 by various authors (details in individual files),
// which is released under the Boost Software License, Version 1.0.

#include "config.h"

#include <iostream>

#include "RoutedForwarding.h"
#include "Node.h"
#include "Link.h"
#include "Bundle.h"
#include "BundlePointer.h"

using namespace DTN;

void
RoutedForwarding::cache( BundlePointer& p )
{
   // We know the BundlePointer is valid when this method is called,
   // so we can forego testing it.
   try
   {
      const Link& l = target( *(p.repr()->bundle()) );
      m_cache[ &l ].push_back( p ); // FIFO
   }
   catch ( ... )
   {
      // do nothing
   }
}

bool
RoutedForwarding::forward( Bundle* b )
{
   if ( 0 == m_owner ) return false;

   // This is FIFO.  Why?  Because a Link that's available clearly
   // didn't have any other Bundles waiting when it went from
   // unavailable to available.  If there are any corner cases in
   // which this turns out not to be true, I'm willing to accept that.
   try
   {
      Link& l = target( *b );
      if ( l.available() )
      {
         m_owner->send( b, l );
         return true;
      }
   }
   catch ( ... )
   {
      return false;
   }
   return false;
}

Bundle*
RoutedForwarding::forwardOn( const Link& l )
{
   if ( 0 == m_owner )
   {
      std::cerr << "Object of type RoutedForwarding has no owner" << std::endl;
      throw Exception( __FILE__ , __LINE__ );
   }

   BundleCache::iterator itr = m_cache.find( &l );
   if ( m_cache.end() == itr )
   {
      return 0;
   }
   while ( 0 != itr->second.size() )
   {
      BundlePointer p = itr->second.front();
      itr->second.pop_front();
      if ( m_owner->validate(p) )
      {
         Bundle* b = p.repr()->bundle();
         m_owner->remove(b,false); // The Link will take ownership
         return b;
      }
   }
   return 0;
}

void
RoutedForwarding::addRouting( RoutingTable* table )
{
   if ( 0 != table )
      m_routing = table;
}

Link&
RoutedForwarding::target( const Bundle& b )
{
   if ( 0 != m_routing )
   {
      return m_routing->target( b );
   }
   else
   {
      throw Exception( __FILE__ , __LINE__ );
   }
}

void
RoutedForwarding::protected_set()
{
   m_cache.clear();
}

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