Uniquify IDs in SVG-Edit

Since we can have several SVG-Edit graphics
on a page, SVG-Edit should assign unique IDs
to elements, and do so in a fashion that survives
re-editing.

To do this, we use a nonce, and record its value in
a custom se:nonce attribute on the <svg> element.
(Is there a better way?). 

Also, preserve the custom se:connector attribute for
later editing purposes.

lib/sanitizer.rb

@@ -60,7 +60,7 @@ module Sanitizer
        patternContentUnits patternTransform patternUnits points
        preserveAspectRatio primitiveUnits r refX refY repeatCount repeatDur
        requiredExtensions requiredFeatures restart rotate rx ry se:connector
-       slope spacing
+       se:nonce slope spacing
        startOffset stdDeviation stemh stemv stop-color stop-opacity
        strikethrough-position strikethrough-thickness stroke stroke-dasharray
        stroke-dashoffset stroke-linecap stroke-linejoin stroke-miterlimit

public/svg-edit/editor/extensions/ext-arrows.js

@@ -12,7 +12,10 @@ $(function() {
 	svgCanvas.addExtension("Arrows", function(S) {
 		var svgcontent = S.svgcontent,
 			addElem = S.addSvgElementFromJson,
+			nonce = S.nonce,
 			selElems;
+
+		svgCanvas.bind('setarrownonce', setArrowNonce);
 			
 		var lang_list = {
 			"en":[
@@ -23,10 +26,20 @@ $(function() {
 			]
 		};
 		
+		var prefix = 'se_arrow_';
+		var arrowprefix = prefix + nonce + '_';
+
 		var pathdata = {
-			fw: {d:"m0,0l10,5l-10,5l5,-5l-5,-5z", refx:8, id:"se_arrow_fw"},
-			bk: {d:"m10,0l-10,5l10,5l-5,-5l5,-5z", refx:2, id:"se_arrow_bk"}
+			fw: {d:"m0,0l10,5l-10,5l5,-5l-5,-5z", refx:8,  id: arrowprefix + 'fw'},
+			bk: {d:"m10,0l-10,5l10,5l-5,-5l5,-5z", refx:2, id: arrowprefix + 'bk'}
 		}
+		
+		function setArrowNonce(window, n) {
+		    arrowprefix = prefix + n + '_';
+			pathdata.fw.id = arrowprefix + 'fw';
+			pathdata.bk.id = arrowprefix + 'bk';
+		}
+
 		function getLinked(elem, attr) {
 			var str = elem.getAttribute(attr);
 			if(!str) return null;
@@ -77,7 +90,7 @@ $(function() {
 		
 		function addMarker(dir, type, id) {
 			// TODO: Make marker (or use?) per arrow type, since refX can be different
-			id = id || 'se_arrow_' + dir;
+			id = id || arrowprefix + dir;
 			
 			var marker = S.getElem(id);
 
@@ -174,7 +187,7 @@ $(function() {
 					var last_id = marker.id;
 					var dir = last_id.indexOf('_fw') !== -1?'fw':'bk';
 					
-					new_marker = addMarker(dir, type, 'se_arrow_' + dir + all_markers.length);
+					new_marker = addMarker(dir, type, arrowprefix + dir + all_markers.length);
 
 					$(new_marker).children().attr('fill', color);
 				}

public/svg-edit/editor/extensions/ext-itex.js

@@ -78,8 +78,6 @@ $(function() {
 				      mrow.appendChild(children[0]);
 				    }
 				    S.sanitizeSvg(math);
-				    //elt.setAttribute('width', math.clientWidth+5);
-				    //elt.setAttribute('height', math.clientHeight+5);
 				    S.call("changed", [elt]);
 				});
 				elt.replaceChild(math, elt.firstChild);

public/svg-edit/editor/svgcanvas.js

@@ -943,6 +943,9 @@ function BatchCommand(text) {
 		
 		$(svgroot).appendTo(container);
 
+    //nonce to uniquify id's
+    var nonce = Math.floor(Math.random()*100001);
+    
 	// map namespace URIs to prefixes		
 	var nsMap = {};
     nsMap[xlinkns] = 'xlink';
@@ -982,6 +985,8 @@ function BatchCommand(text) {
 		y: 480,
 		overflow: 'visible',
 		xmlns: svgns,
+		"xmlns:se": se_ns,
+		"se:nonce": nonce,
 		"xmlns:xlink": xlinkns
 	}).appendTo(svgroot);
 
@@ -1284,7 +1289,7 @@ function BatchCommand(text) {
 // private functions
 	var getId = function() {
 		if (events["getid"]) return call("getid", obj_num);
-		return idprefix + obj_num;
+		return idprefix + nonce +'_' + obj_num;
 	};
 
 	var getNextId = function() {
@@ -5602,6 +5607,15 @@ function BatchCommand(text) {
         
     	    // set new svg document
         	svgcontent = svgroot.appendChild(svgdoc.importNode(newDoc.documentElement, true));
+        	// retrieve or set the nonce
+        	n = svgcontent.getAttributeNS(se_ns, 'nonce');
+        	if (n) {
+        		nonce = n;
+        		if (extensions["Arrows"])  call("setarrownonce", n) ;
+        	} else {
+        		svgcontent.setAttributeNS(xmlnsns, 'xml:se', se_ns); 
+        		svgcontent.setAttributeNS(se_ns, 'se:nonce', nonce); 
+         	}         
         	// change image href vals if possible
         	$(svgcontent).find('image').each(function() {
         		var image = this;
@@ -8049,6 +8063,7 @@ function BatchCommand(text) {
 			var ext = ext_func($.extend(canvas.getPrivateMethods(), {
 				svgroot: svgroot,
 				svgcontent: svgcontent,
+				nonce: nonce,
 				selectorManager: selectorManager
 			}));
 			extensions[name] = ext;