/*
  Copyright (C) 2010 Paul Davis
  Author: Torben Hohn

  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 "ardour/graph.h"
#include "ardour/graphnode.h"
#include "ardour/route.h"

using namespace ARDOUR;

GraphNode::GraphNode (boost::shared_ptr<Graph> graph)
	: _graph (graph)
{
}

GraphNode::~GraphNode ()
{
}

void
GraphNode::prep (int chain)
{
	/* This is the number of nodes that directly feed us */
	g_atomic_int_set (&_refcount, _init_refcount[chain]);
}

/** Called by an upstream node, when it has completed processing */
void
GraphNode::trigger ()
{
	/* check if we can run */
	if (g_atomic_int_dec_and_test (&_refcount)) {
#if 0 // TODO optimize: remove prep()
		/* reset reference count for next cycle */
		g_atomic_int_set (&_refcount, _init_refcount[chain]);
#endif
		/* All nodes that feed this node have completed, so this node be processed now. */
		_graph->trigger (this);
	}
}

void
GraphNode::finish (int chain)
{
	node_set_t::iterator i;
	bool                 feeds = false;

	/* Notify downstream nodes that depend on this node */
	for (i = _activation_set[chain].begin (); i != _activation_set[chain].end (); ++i) {
		(*i)->trigger ();
		feeds = true;
	}

	if (!feeds) {
		/* This node is a terminal node that does not feed another note,
		 * so notify the graph to decrement the the finished count */
		_graph->reached_terminal_node ();
	}
}

void
GraphNode::process ()
{
	_graph->process_one_route (dynamic_cast<Route*> (this));
}