From 0ab486e7ee68e94bed366816099c8ea535245ba1 Mon Sep 17 00:00:00 2001
From: sbosse <sbosse@uni-bremen.de>
Date: Mon, 21 Jul 2025 23:41:44 +0200
Subject: [PATCH] Mon 21 Jul 22:43:21 CEST 2025

---
 .../stage/mxMinimumCycleRemover.js            | 108 ++++++++++++++++++
 1 file changed, 108 insertions(+)
 create mode 100644 js/ui/mxgraph/src/js/layout/hierarchical/stage/mxMinimumCycleRemover.js

diff --git a/js/ui/mxgraph/src/js/layout/hierarchical/stage/mxMinimumCycleRemover.js b/js/ui/mxgraph/src/js/layout/hierarchical/stage/mxMinimumCycleRemover.js
new file mode 100644
index 0000000..7046755
--- /dev/null
+++ b/js/ui/mxgraph/src/js/layout/hierarchical/stage/mxMinimumCycleRemover.js
@@ -0,0 +1,108 @@
+/**
+ * Copyright (c) 2006-2015, JGraph Ltd
+ * Copyright (c) 2006-2015, Gaudenz Alder
+ */
+/**
+ * Class: mxMinimumCycleRemover
+ * 
+ * An implementation of the first stage of the Sugiyama layout. Straightforward
+ * longest path calculation of layer assignment
+ * 
+ * Constructor: mxMinimumCycleRemover
+ *
+ * Creates a cycle remover for the given internal model.
+ */
+function mxMinimumCycleRemover(layout)
+{
+	this.layout = layout;
+};
+
+/**
+ * Extends mxHierarchicalLayoutStage.
+ */
+mxMinimumCycleRemover.prototype = new mxHierarchicalLayoutStage();
+mxMinimumCycleRemover.prototype.constructor = mxMinimumCycleRemover;
+
+/**
+ * Variable: layout
+ * 
+ * Reference to the enclosing <mxHierarchicalLayout>.
+ */
+mxMinimumCycleRemover.prototype.layout = null;
+
+/**
+ * Function: execute
+ * 
+ * Takes the graph detail and configuration information within the facade
+ * and creates the resulting laid out graph within that facade for further
+ * use.
+ */
+mxMinimumCycleRemover.prototype.execute = function(parent)
+{
+	var model = this.layout.getModel();
+	var seenNodes = new Object();
+	var unseenNodesArray = model.vertexMapper.getValues();
+	var unseenNodes = new Object();
+	
+	for (var i = 0; i < unseenNodesArray.length; i++)
+	{
+		unseenNodes[unseenNodesArray[i].id] = unseenNodesArray[i];
+	}
+	
+	// Perform a dfs through the internal model. If a cycle is found,
+	// reverse it.
+	var rootsArray = null;
+	
+	if (model.roots != null)
+	{
+		var modelRoots = model.roots;
+		rootsArray = [];
+		
+		for (var i = 0; i < modelRoots.length; i++)
+		{
+			rootsArray[i] = model.vertexMapper.get(modelRoots[i]);
+		}
+	}
+
+	model.visit(function(parent, node, connectingEdge, layer, seen)
+	{
+		// Check if the cell is in it's own ancestor list, if so
+		// invert the connecting edge and reverse the target/source
+		// relationship to that edge in the parent and the cell
+		if (node.isAncestor(parent))
+		{
+			connectingEdge.invert();
+			mxUtils.remove(connectingEdge, parent.connectsAsSource);
+			parent.connectsAsTarget.push(connectingEdge);
+			mxUtils.remove(connectingEdge, node.connectsAsTarget);
+			node.connectsAsSource.push(connectingEdge);
+		}
+		
+		seenNodes[node.id] = node;
+		delete unseenNodes[node.id];
+	}, rootsArray, true, null);
+
+	// If there are any nodes that should be nodes that the dfs can miss
+	// these need to be processed with the dfs and the roots assigned
+	// correctly to form a correct internal model
+	var seenNodesCopy = mxUtils.clone(seenNodes, null, true);
+
+	// Pick a random cell and dfs from it
+	model.visit(function(parent, node, connectingEdge, layer, seen)
+	{
+		// Check if the cell is in it's own ancestor list, if so
+		// invert the connecting edge and reverse the target/source
+		// relationship to that edge in the parent and the cell
+		if (node.isAncestor(parent))
+		{
+			connectingEdge.invert();
+			mxUtils.remove(connectingEdge, parent.connectsAsSource);
+			node.connectsAsSource.push(connectingEdge);
+			parent.connectsAsTarget.push(connectingEdge);
+			mxUtils.remove(connectingEdge, node.connectsAsTarget);
+		}
+		
+		seenNodes[node.id] = node;
+		delete unseenNodes[node.id];
+	}, unseenNodes, true, seenNodesCopy);
+};