ITSSTOOLS/core/relationgraph.class.inc.php

<?php
// Copyright (C) 2015 Combodo SARL
//
//   This file is part of iTop.
//
//   iTop is free software; you can redistribute it and/or modify
//   it under the terms of the GNU Affero General Public License as published by
//   the Free Software Foundation, either version 3 of the License, or
//   (at your option) any later version.
//
//   iTop 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 Affero General Public License for more details.
//
//   You should have received a copy of the GNU Affero General Public License
//   along with iTop. If not, see <http://www.gnu.org/licenses/>
/**
 * Data structures (i.e. PHP classes) to manage "graphs"
 *
 * @copyright   Copyright (C) 2015 Combodo SARL
 * @license     http://opensource.org/licenses/AGPL-3.0
 * 
 * Example:
 * require_once('../approot.inc.php');
 * require_once(APPROOT.'application/startup.inc.php');
 * require_once(APPROOT.'core/relationgraph.class.inc.php');
 * 
 * $oGraph = new RelationGraph();
 * 
 * $oNode1 = new RelationNode($oGraph, 'Source1');
 * $oNode2 = new RelationNode($oGraph, 'Sink');
 * $oEdge1 = new RelationEdge($oGraph, 'flow1', $oNode1, $oNode2);
 * $oNode3 = new RelationNode($oGraph, 'Source2');
 * $oEdge2 = new RelationEdge($oGraph, 'flow2', $oNode3, $oNode2);
 * $oEdge2 = new RelationEdge($oGraph, 'flow3', $oNode2, $oNode3);
 * $oEdge2 = new RelationEdge($oGraph, 'flow4', $oNode1, $oNode3);
 * 
 * echo $oGraph->DumpAsHtmlImage(); // requires graphviz
 * echo $oGraph->DumpAsHtmlText();
 */

/**
 * Exceptions generated by the RelationGraph class
 */
class RelationGraphException extends Exception
{
	
}

/**
 * The parent class of all elements which can be part of a RelationGraph
 */
class RelationElement
{
	protected $sId;
	protected $aProperties;
	
	/**
	 * Constructor
	 * @param string $sId The identifier of the object in the graph
	 */
	public function __construct($sId)
	{
		$this->sId = $sId;
		$this->aProperties = array();
	}
	
	/**
	 * Get the identifier of the object in the graph
	 * @return string
	 */
	public function GetId()
	{
		return $this->sId;
	}
	
	/**
	 * Get the value of the given named property for the object
	 * @param string $sPropName The name of the property to get
	 * @param mixed $defaultValue The default value to return if the property does not exist
	 * @return mixed
	 */
	public function GetProperty($sPropName, $defaultValue)
	{
		return array_key_exists($sPropName, $this->aProperties) ? $this->aProperties[$sPropName] : $defaultValue;
	}

	/**
	 * Set the value of a named property for the object
	 * @param string $sPropName The name of the property to set
	 * @param mixed $value
	 * @return void
	 */
	public function SetProperty($sPropName, $value)
	{
		$this->aProperties[$sPropName] = $value;
	}
	
	/**
	 * Get all the known properties of the object
	 * @return Ambigous <multitype:, mixed>
	 */
	public function GetProperties()
	{
		return $this->aProperties;
	}
}

/**
 * A Node inside a RelationGraph
 */
class RelationNode extends RelationElement
{
	protected $aIncomingEdges;
	protected $aOutgoingEdges;
	
	/**
	 * Create a new node inside a graph
	 * @param RelationGraph $oGraph
	 * @param string $sId The unique identifier of this node inside the graph
	 */
	public function __construct(RelationGraph $oGraph, $sId)
	{
		parent::__construct($sId);
		$this->aIncomingEdges = array();
		$this->aOutgoingEdges = array();
		$oGraph->_AddNode($this);
	}
	
	/**
	 * INTERNAL USE ONLY
	 * @param RelationEdge $oEdge
	 */
	public function _AddIncomingEdge(RelationEdge $oEdge)
	{
		$this->aIncomingEdges[$oEdge->GetId()] = $oEdge;
	}

	/**
	 * INTERNAL USE ONLY
	 * @param RelationEdge $oEdge
	 */
	public function _AddOutgoingEdge(RelationEdge $oEdge)
	{
		$this->aOutgoingEdges[$oEdge->GetId()] = $oEdge;
	}
	
	/**
	 * Get the list of  all incoming edges on the current node
	 * @return Ambigous <multitype:, RelationEdge>
	 */
	public function GetIncomingEdges()
	{
		return $this->aIncomingEdges;
	}
	
	/**
	 * Get the list of  all outgoing edges from the current node
	 * @return Ambigous <multitype:, RelationEdge>
	 */
	public function GetOutgoingEdges()
	{
		return $this->aOutgoingEdges;
	}
	
}

/**
 * A directed Edge inside a RelationGraph
 */
class RelationEdge extends RelationElement
{
	protected $oSourceNode;
	protected $oSinkNode;
	
	/**
	 * Create a new directed edge inside the given graph
	 * @param RelationGraph $oGraph
	 * @param string $sId The unique identifier of this edge in the graph
	 * @param RelationNode $oSourceNode
	 * @param RelationNode $oSinkNode
	 */
	public function __construct(RelationGraph $oGraph, $sId, RelationNode $oSourceNode, RelationNode $oSinkNode)
	{
		parent::__construct($sId);
		$this->oSourceNode = $oSourceNode;
		$this->oSinkNode = $oSinkNode;
		$oGraph->_AddEdge($this);
	}
	
	/**
	 * Get the "source" node for this edge
	 * @return RelationNode
	 */
	public function GetSourceNode()
	{
		return $this->oSourceNode;
	}
	
	/**
	 * Get the "sink" node for this edge
	 * @return RelationNode
	 */
	public function GetSinkNode()
	{
		return $this->oSinkNode;
	}
}

/**
 * The main container for a graph: RelationGraph
 */
class RelationGraph
{
	protected $aNodes;
	protected $aEdges;
	
	/**
	 * Creates a new empty graph
	 */
	public function __construct()
	{
		$this->aNodes = array();
		$this->aEdges = array();
	}
	
	/**
	 * INTERNAL USE ONLY
	 * @return Ambigous <multitype:, RelationNode>
	 */
	public function _GetNodes()
	{
		return $this->aNodes;
	}
	
	/**
	 * INTERNAL USE ONLY
	 * @return Ambigous <multitype:, RelationNode>
	 */
	public function _GetEdges()
	{
		return $this->aEdges;
	}
	
	/**
	 * INTERNAL USE ONLY
	 * @return Ambigous <multitype:, RelationNode>
	 */
	public function _AddNode(RelationNode $oNode)
	{
		if (array_key_exists($oNode->GetId(), $this->aNodes)) throw new RelationGraphException('Cannot add node (id='.$oNode->GetId().') to the graph. A node with the same id already exists inthe graph.');
		
		$this->aNodes[$oNode->GetId()] = $oNode;
	}
	
	/**
	 * Get the node identified by $sId or null if not found
	 * @param string $sId
	 * @return NULL | RelationNode
	 */
	public function GetNode($sId)
	{
		return array_key_exists($sId, $this->aNodes) ? $this->aNodes[$sId] : null; 
	}

	/**
	 * INTERNAL USE ONLY
	 * @param RelationEdge $oEdge
	 * @throws RelationGraphException
	 */
	public function _AddEdge(RelationEdge $oEdge)
	{
		if (array_key_exists($oEdge->GetId(), $this->aEdges)) throw new RelationGraphException('Cannot add edge (id='.$oEdge->GetId().') to the graph. An edge with the same id already exists inthe graph.');
		
		$this->aEdges[$oEdge->GetId()] = $oEdge;
		$oEdge->GetSourceNode()->_AddOutgoingEdge($oEdge);
		$oEdge->GetSinkNode()->_AddIncomingEdge($oEdge);
	}
	
	/**
	 * Get the edge indentified by $sId or null if not found
	 * @param string $sId
	 * @return NULL | RelationEdge
	 */
	public function GetEdge($sId)
	{
		return array_key_exists($sId, $this->aEdges) ? $this->aEdges[$sId] : null;
	}
	
	/**
	 * Get the description of the graph as a text string in the graphviz 'dot' language
	 * @return string
	 */
	public function GetDotDescription()
	{
		$sDot =
<<<EOF
digraph finite_state_machine {
graph [bgcolor = "transparent"];
rankdir=LR;
size="12,12"
node [ fontname=Verdana style=filled fillcolor="#ffffff" ];
edge [ fontname=Verdana ];

EOF
		;

		$oIterator = new RelationTypeIterator($this, 'Node');
		
		foreach($oIterator as $key => $oNode)
		{
			if (count($oNode->GetOutgoingEdges()) > 0)
			{
				foreach($oNode->GetOutgoingEdges() as $oEdge)
				{
					$sDot .= "\t".$oNode->GetId()." -> ".$oEdge->GetSinkNode()->GetId()." [ label=\"".$oEdge->GetId()."\" ];\n";
				}
			}
			else
			{
				$sDot .= "\t".$oNode->GetId().";\n";
			}
		}
		
		$sDot .= "}\n";
		return $sDot;		
	}
	
	/**
	 * Get the description of the graph as an embedded PNG image (using a data: url) as
	 * generated by graphviz (requires graphviz to be installed on the machine and the path to
	 * dot/dot.exe to be configured in the iTop configuration file)
	 * Note: the function creates temporary files in APPROOT/data/tmp
	 * @return string
	 */
	public function DumpAsHtmlImage()
	{
		$sDotExecutable = MetaModel::GetConfig()->Get('graphviz_path');
		if (file_exists($sDotExecutable))
		{
			// create the file with Graphviz
			if (!is_dir(APPROOT."data"))
			{
				@mkdir(APPROOT."data");
			}
			if (!is_dir(APPROOT."data/tmp"))
			{
				@mkdir(APPROOT."data/tmp");
			}
			$sImageFilePath = tempnam(APPROOT."data/tmp", 'png-');
			$sDotDescription = $this->GetDotDescription();
			$sDotFilePath = tempnam(APPROOT."data/tmp", 'dot-');
		
			$rFile = @fopen($sDotFilePath, "w");
			@fwrite($rFile, $sDotDescription);
			@fclose($rFile);
			$aOutput = array();
			$CommandLine = "$sDotExecutable -v -Tpng < $sDotFilePath -o$sImageFilePath 2>&1";
		
			exec($CommandLine, $aOutput, $iRetCode);
			if ($iRetCode != 0)
			{
				$sHtml = '';
				$sHtml .= "<p><b>Error:</b></p>";
				$sHtml .= "<p>The command: <pre>$CommandLine</pre> returned $iRetCode</p>";
				$sHtml .= "<p>The output of the command is:<pre>\n".implode("\n", $aOutput)."</pre></p>";
				$sHtml .= "<hr>";
				$sHtml .= "<p>Content of the '".basename($sDotFilePath)."' file:<pre>\n$sDotDescription</pre>";
			}
			else
			{
				$sHtml = '<img src="data:image/png;base64,'.base64_encode(file_get_contents($sImageFilePath)).'">';
				@unlink($sImageFilePath);
			}
			@unlink($sDotFilePath);
		}
		return $sHtml;
	}
	
	/**
	 * Get the description of the graph as some HTML text
	 * @return string
	 */
	public function DumpAsHTMLText()
	{
		$sHtml = '';
		$oIterator = new RelationTypeIterator($this);
		
		foreach($oIterator as $key => $oElement)
		{
			$sHtml .= "<p>$key: ".get_class($oElement)."::".$oElement->GetId()."</p>";
		
			switch(get_class($oElement))
			{
				case 'RelationNode':
					if (count($oElement->GetIncomingEdges()) > 0)
					{
						$sHtml .= "<ul>Incoming edges:\n";
						foreach($oElement->GetIncomingEdges() as $oEdge)
						{
							$sHtml .= "<li>From: ".$oEdge->GetSourceNode()->GetId()."</li>\n";
						}
						$sHtml .= "</ul>\n";
					}
					if (count($oElement->GetOutgoingEdges()) > 0)
					{
						$sHtml .= "<ul>Outgoing edges:\n";
						foreach($oElement->GetOutgoingEdges() as $oEdge)
						{
							$sHtml .= "<li>To: ".$oEdge->GetSinkNode()->GetId()."</li>\n";
						}
						$sHtml .= "</ul>\n";
					}
					break;
		
				case 'RelationEdge':
					$sHtml .= "<p>From: ".$oElement->GetSourceNode()->GetId().", to:".$oElement->GetSinkNode()->GetId()."</p>\n";
					break;
			}
		}
		return $sHtml;		
	}
}

/**
 * A simple iterator to "browse" the whole content of a graph,
 * either for only a given type of elements (Node | Edge) or for every type.
 */
class RelationTypeIterator implements Iterator
{
	protected $iCurrentIdx;
	protected $aList;
	
	/**
	 * Constructor
	 * @param RelationGraph $oGraph The graph to browse
	 * @param string $sType "Node", "Edge" or null
	 */
	public function __construct(RelationGraph $oGraph, $sType = null)
	{
		$this->iCurrentIdx = -1;
		$this->aList = array();
		
		switch($sType)
		{
			case 'Node':
			foreach($oGraph->_GetNodes() as $oNode) $this->aList[] = $oNode;
			break;
			
			case 'Edge':
			foreach($oGraph->_GetEdges() as $oEdge) $this->aList[] = $oEdge;
			break;
			
			default:
			foreach($oGraph->_GetNodes() as $oNode) $this->aList[] = $oNode;
			foreach($oGraph->_GetEdges() as $oEdge) $this->aList[] = $oEdge;				
		}
	}
	
	public function rewind()
	{
		$this->iCurrentIdx = 0;
	}
	
	public function valid()
	{
		return array_key_exists($this->iCurrentIdx, $this->aList);
	}
	
	public function next()
	{
		$this->iCurrentIdx++;
	}
	
	public function current()
	{
		return $this->aList[$this->iCurrentIdx];
	}
	
	public function key()
	{
		return $this->iCurrentIdx;
	}
}