Major refactoring of rendering mechanism

We now use a fake DOM implementation on the server to let us share more
rendering code between the text output vs. DOM output paths.

core/modules/utils/dom/styles.js

@@ -37,7 +37,9 @@ StylesheetManager.prototype.addStylesheet = function(title) {
 	var parser = this.wiki.parseTiddler(title),
 		renderTree = new $tw.WikiRenderTree(parser,{wiki: this.wiki, context: {tiddlerTitle: title}});
 	renderTree.execute();
-	var text = renderTree.render("text/plain");
+	var container = $tw.document.createElement("div");
+	renderTree.renderInDom(container);
+	var text = container.textContent;
 	// Create a style element and put it in the document
 	var styleNode = document.createElement("style");
 	styleNode.setAttribute("type","text/css");

core/modules/utils/fakedom.js

@@ -0,0 +1,122 @@
+/*\
+title: $:/core/modules/utils/fakedom.js
+type: application/javascript
+module-type: global
+
+A barebones implementation of DOM interfaces needed by the rendering mechanism.
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+var TW_TextNode = function(text) {
+	this.textContent = text;
+}
+
+var TW_Element = function(tag) {
+	this.tag = tag;
+	this.attributes = {};
+	this.isRaw = false;
+	this.children = [];
+}
+
+TW_Element.prototype.setAttribute = function(name,value) {
+	if(this.isRaw) {
+		throw "Cannot setAttribute on a raw TW_Element";
+	}
+	this.attributes[name] = value;
+};
+
+TW_Element.prototype.setAttributeNS = function(namespace,name,value) {
+	this.setAttribute(name,value);
+};
+
+TW_Element.prototype.appendChild = function(node) {
+	this.children.push(node);
+	node.parentNode = this;
+};
+
+TW_Element.prototype.addEventListener = function(type,listener,useCapture) {
+	// Do nothing
+};
+
+Object.defineProperty(TW_Element.prototype, "outerHTML", {
+    get: function() {
+		var output = [],attr,a,v;
+		output.push("<",this.tag);
+		if(this.attributes) {
+			attr = [];
+			for(a in this.attributes) {
+				attr.push(a);
+			}
+			attr.sort();
+			for(a=0; a<attr.length; a++) {
+				v = this.attributes[attr[a]];
+				if(v !== undefined) {
+					output.push(" ",attr[a],"='",$tw.utils.htmlEncode(v),"'");
+				}
+			}
+		}
+		output.push(">\n");
+		if($tw.config.htmlVoidElements.indexOf(this.tag) === -1) {
+			output.push(this.innerHTML);
+			output.push("</",this.tag,">");
+		}
+		return output.join("");
+    }
+});
+
+Object.defineProperty(TW_Element.prototype, "innerHTML", {
+	get: function() {
+		if(this.isRaw) {
+			return this.rawHTML;
+		} else {
+			var b = [];
+			$tw.utils.each(this.children,function(node) {
+				if(node instanceof TW_Element) {
+					b.push(node.outerHTML);
+				} else if(node instanceof TW_TextNode) {
+					b.push($tw.utils.htmlEncode(node.textContent));
+				}
+			});
+			return b.join("");
+		}
+	},
+    set: function(value) {
+    	this.isRaw = true;
+    	this.rawHTML = value;
+    }
+});
+
+Object.defineProperty(TW_Element.prototype, "textContent", {
+	get: function() {
+		if(this.isRaw) {
+			throw "Cannot get textContent on a raw TW_Element";
+		} else {
+			var b = [];
+			$tw.utils.each(this.children,function(node) {
+				b.push(node.textContent);
+			});
+			return b.join("");
+		}
+	}
+});
+
+var document = {
+	createElementNS: function(namespace,tag) {
+		return new TW_Element(tag);
+	},
+	createElement: function(tag) {
+		return new TW_Element(tag);
+	},
+	createTextNode: function(text) {
+		return new TW_TextNode(text);
+	},
+};
+
+exports.document = document;
+
+})();