From 14243acec9a320cd965d82e9122f8a53efcdcf3a Mon Sep 17 00:00:00 2001
From: Jeremy Ruston <jeremy@osmosoft.com>
Date: Fri, 6 Jan 2012 17:40:22 +0000
Subject: [PATCH] Adding caching for tiddler parse trees, render functions, and
 renditions

---
 js/Tiddler.js           |  3 +++
 js/WikiStore.js         | 39 ++++++++++++++++++++++++++++++++-------
 js/WikiTextParseTree.js |  8 --------
 tiddlywiki5/styles.css  |  2 +-
 4 files changed, 36 insertions(+), 16 deletions(-)

diff --git a/js/Tiddler.js b/js/Tiddler.js
index 0c329bbf0..25f8a6705 100755
--- a/js/Tiddler.js
+++ b/js/Tiddler.js
@@ -22,6 +22,9 @@ var utils = require("./Utils.js"),
 	WikiTextParser = require("./WikiTextParser.js").WikiTextParser;
 
 var Tiddler = function(/* tiddler,fields */) {
+	this.parseTree = null; // Caches the parse tree for the tiddler
+	this.renderers = {}; // Caches rendering functions for this tiddler (indexed by MIME type)
+	this.renditions = {}; // Caches the renditions produced by those functions (indexed by MIME type)
 	this.fields = {};
 	for(var c=0; c<arguments.length; c++) {
 		var arg = arguments[c],
diff --git a/js/WikiStore.js b/js/WikiStore.js
index 7c5be1269..784826274 100755
--- a/js/WikiStore.js
+++ b/js/WikiStore.js
@@ -280,24 +280,49 @@ WikiStore.prototype.parseText = function(type,text) {
 WikiStore.prototype.parseTiddler = function(title) {
 	var tiddler = this.getTiddler(title);
 	if(tiddler) {
-		return this.parseText(tiddler.fields.type,tiddler.fields.text);
+		// Check the cache
+		if(!tiddler.parseTree) {
+			tiddler.parseTree = this.parseText(tiddler.fields.type,tiddler.fields.text);
+		}
+		return tiddler.parseTree;
 	} else {
 		return null;
 	}
 };
 
+/*
+Compiles a JavaScript function that renders a tiddler in a particular MIME type
+*/
+WikiStore.prototype.compileTiddler = function(title,type) {
+	/*jslint evil: true */
+	var tiddler = this.getTiddler(title);
+	if(tiddler) {
+		if(!tiddler.renderers[type]) {
+			var tree = this.parseTiddler(title);
+			tiddler.renderers[type] = eval(tree.compile(type));
+		}
+		return tiddler.renderers[type];
+	} else {
+		return null;	
+	}
+};
+
 /*
 Render a tiddler to a particular MIME type. Optionally render it with a different tiddler
-as the context. This option is used to render a tiddler through a template as
+as the context. This option is used to render a tiddler through a template eg
 store.renderTiddler("text/html",templateTitle,tiddlerTitle)
 */
 WikiStore.prototype.renderTiddler = function(type,title,asTitle) {
-	var parser = this.parseTiddler(title),
-		asTitleExists = asTitle ? this.tiddlerExists(asTitle) : true;
-	if(parser && asTitleExists) {
-		return parser.render(type,parser.children,this,asTitle ? asTitle : title);
+	var tiddler = this.getTiddler(title),
+		fn = this.compileTiddler(title,type);
+	if(asTitle) {
+		var asTiddler = this.getTiddler(asTitle);
+		return fn(asTiddler,this,utils);
 	} else {
-		return null;
+		if(!tiddler.renditions[type]) {
+			tiddler.renditions[type] = fn(tiddler,this,utils);
+		}
+		return tiddler.renditions[type];
 	}
 };
 
diff --git a/js/WikiTextParseTree.js b/js/WikiTextParseTree.js
index 2320ae425..81f4e04a7 100644
--- a/js/WikiTextParseTree.js
+++ b/js/WikiTextParseTree.js
@@ -20,14 +20,6 @@ var WikiTextParseTree = function(tree,store) {
 	this.store = store;
 };
 
-WikiTextParseTree.prototype.render = function(type,treenode,store,title) {
-	/*jslint evil: true */
-	var code = this.compile(type,treenode);
-	var fn = eval(code);
-	var tiddler = store.getTiddler(title);
-	return fn(tiddler,store,utils);
-};
-
 // Compile the parse tree into a JavaScript function that returns the required
 // representation of the tree
 WikiTextParseTree.prototype.compile = function(type,treenode) {
diff --git a/tiddlywiki5/styles.css b/tiddlywiki5/styles.css
index 131a03353..389e1ea60 100644
--- a/tiddlywiki5/styles.css
+++ b/tiddlywiki5/styles.css
@@ -73,7 +73,7 @@ a {
 }
 
 a.linkExternal::before {
-    content: "\27a0";
+    content: "\27a0\00a0";
 }
 
 a:hover {