1 files changed, 213 insertions, 0 deletions
diff --git a/src/js/util/mxAutoSaveManager.js b/src/js/util/mxAutoSaveManager.js
new file mode 100644
index 0000000..85c23dc
--- /dev/null
+++ b/src/js/util/mxAutoSaveManager.js
@@ -0,0 +1,213 @@
+/**
+ * $Id: mxAutoSaveManager.js,v 1.9 2010-09-16 09:10:21 gaudenz Exp $
+ * Copyright (c) 2006-2010, JGraph Ltd
+ */
+/**
+ * Class: mxAutoSaveManager
+ * 
+ * Manager for automatically saving diagrams. The <save> hook must be
+ * implemented.
+ * 
+ * Example:
+ * 
+ * (code)
+ * var mgr = new mxAutoSaveManager(editor.graph);
+ * mgr.save = function()
+ * {
+ *   mxLog.show();
+ *   mxLog.debug('save');
+ * };
+ * (end)
+ * 
+ * Constructor: mxAutoSaveManager
+ *
+ * Constructs a new automatic layout for the given graph.
+ *
+ * Arguments:
+ * 
+ * graph - Reference to the enclosing graph. 
+ */
+function mxAutoSaveManager(graph)
+{
+	// Notifies the manager of a change
+	this.changeHandler = mxUtils.bind(this, function(sender, evt)
+	{
+		if (this.isEnabled())
+		{
+			this.graphModelChanged(evt.getProperty('edit').changes);
+		}
+	});
+
+	this.setGraph(graph);
+};
+
+/**
+ * Extends mxEventSource.
+ */
+mxAutoSaveManager.prototype = new mxEventSource();
+mxAutoSaveManager.prototype.constructor = mxAutoSaveManager;
+
+/**
+ * Variable: graph
+ * 
+ * Reference to the enclosing <mxGraph>.
+ */
+mxAutoSaveManager.prototype.graph = null;
+
+/**
+ * Variable: autoSaveDelay
+ * 
+ * Minimum amount of seconds between two consecutive autosaves. Eg. a
+ * value of 1 (s) means the graph is not stored more than once per second.
+ * Default is 10.
+ */
+mxAutoSaveManager.prototype.autoSaveDelay = 10;
+
+/**
+ * Variable: autoSaveThrottle
+ * 
+ * Minimum amount of seconds between two consecutive autosaves triggered by
+ * more than <autoSaveThreshhold> changes within a timespan of less than
+ * <autoSaveDelay> seconds. Eg. a value of 1 (s) means the graph is not
+ * stored more than once per second even if there are more than
+ * <autoSaveThreshold> changes within that timespan. Default is 2.
+ */
+mxAutoSaveManager.prototype.autoSaveThrottle = 2;
+
+/**
+ * Variable: autoSaveThreshold
+ * 
+ * Minimum amount of ignored changes before an autosave. Eg. a value of 2
+ * means after 2 change of the graph model the autosave will trigger if the
+ * condition below is true. Default is 5.
+ */
+mxAutoSaveManager.prototype.autoSaveThreshold = 5;
+
+/**
+ * Variable: ignoredChanges
+ * 
+ * Counter for ignored changes in autosave.
+ */
+mxAutoSaveManager.prototype.ignoredChanges = 0;
+
+/**
+ * Variable: lastSnapshot
+ * 
+ * Used for autosaving. See <autosave>.
+ */
+mxAutoSaveManager.prototype.lastSnapshot = 0;
+
+/**
+ * Variable: enabled
+ * 
+ * Specifies if event handling is enabled. Default is true.
+ */
+mxAutoSaveManager.prototype.enabled = true;
+
+/**
+ * Variable: changeHandler
+ * 
+ * Holds the function that handles graph model changes.
+ */
+mxAutoSaveManager.prototype.changeHandler = null;
+
+/**
+ * Function: isEnabled
+ * 
+ * Returns true if events are handled. This implementation
+ * returns <enabled>.
+ */
+mxAutoSaveManager.prototype.isEnabled = function()
+{
+	return this.enabled;
+};
+
+/**
+ * Function: setEnabled
+ * 
+ * Enables or disables event handling. This implementation
+ * updates <enabled>.
+ * 
+ * Parameters:
+ * 
+ * enabled - Boolean that specifies the new enabled state.
+ */
+mxAutoSaveManager.prototype.setEnabled = function(value)
+{
+	this.enabled = value;
+};
+
+/**
+ * Function: setGraph
+ * 
+ * Sets the graph that the layouts operate on.
+ */
+mxAutoSaveManager.prototype.setGraph = function(graph)
+{
+	if (this.graph != null)
+	{
+		this.graph.getModel().removeListener(this.changeHandler);
+	}
+	
+	this.graph = graph;
+	
+	if (this.graph != null)
+	{
+		this.graph.getModel().addListener(mxEvent.CHANGE, this.changeHandler);
+	}
+};
+
+/**
+ * Function: save
+ * 
+ * Empty hook that is called if the graph should be saved.
+ */
+mxAutoSaveManager.prototype.save = function()
+{
+	// empty
+};
+
+/**
+ * Function: graphModelChanged
+ * 
+ * Invoked when the graph model has changed.
+ */
+mxAutoSaveManager.prototype.graphModelChanged = function(changes)
+{
+	var now = new Date().getTime();
+	var dt = (now - this.lastSnapshot) / 1000;
+	
+	if (dt > this.autoSaveDelay ||
+		(this.ignoredChanges >= this.autoSaveThreshold &&
+		 dt > this.autoSaveThrottle))
+	{
+		this.save();
+		this.reset();
+	}
+	else
+	{
+		// Increments the number of ignored changes
+		this.ignoredChanges++;
+	}
+};
+
+/**
+ * Function: reset
+ * 
+ * Resets all counters.
+ */
+mxAutoSaveManager.prototype.reset = function()
+{
+	this.lastSnapshot = new Date().getTime();
+	this.ignoredChanges = 0;
+};
+
+/**
+ * Function: destroy
+ * 
+ * Removes all handlers from the <graph> and deletes the reference to it.
+ */
+mxAutoSaveManager.prototype.destroy = function()
+{
+	this.setGraph(null);
+};