From b898afe3e502867bae4de05f4db6167607cea587 Mon Sep 17 00:00:00 2001
From: Jeremy Ruston <jeremy@osmosoft.com>
Date: Tue, 17 Jan 2012 13:01:55 +0000
Subject: [PATCH] Refactor the Tiddler object to enforce immutability

And in the process move the fields out of the fields member
---
 js/BitmapParser.js                |  2 +-
 js/Recipe.js                      | 24 +++++------
 js/SVGParser.js                   |  2 +-
 js/Tiddler.js                     | 71 +++++++++++++++++++++++--------
 js/TiddlerOutput.js               | 37 ++++++++--------
 js/WikiStore.js                   | 54 +++++++++++------------
 js/macros/info.js                 |  2 +-
 js/macros/list.js                 |  4 +-
 js/macros/tiddler.js              |  4 +-
 js/macros/view.js                 |  4 +-
 test/wikitests/SeventhTiddler.tid |  2 +-
 tiddlywiki.js                     |  2 +-
 12 files changed, 120 insertions(+), 88 deletions(-)

diff --git a/js/BitmapParser.js b/js/BitmapParser.js
index 21690b2d4..1aaffe1fa 100644
--- a/js/BitmapParser.js
+++ b/js/BitmapParser.js
@@ -16,7 +16,7 @@ var BitmapParseTree = function() {
 
 BitmapParseTree.prototype.compile = function(type) {
 	if(type === "text/html") {
-		return "(function (tiddler,store,utils) {return '<img src=\"data:' + tiddler.fields.type + ';base64,' + tiddler.fields.text + '\">';})";
+		return "(function (tiddler,store,utils) {return '<img src=\"data:' + tiddler.type + ';base64,' + tiddler.text + '\">';})";
 	} else {
 		return null;
 	}
diff --git a/js/Recipe.js b/js/Recipe.js
index a97d1bdfc..4ffba500d 100755
--- a/js/Recipe.js
+++ b/js/Recipe.js
@@ -132,7 +132,7 @@ Recipe.prototype.loadTiddlerFiles = function(recipeLine) {
 			filename = path.basename(filepath), // eg *.js
 			posStar = filename.indexOf("*");
 		if(posStar !== -1) {
-			var fileRegExp = new RegExp("^" + filename.replace(/[-[\]{}()+?.,\\^$|#\s]/g, "\\$&").replace("*",".*") + "$");
+			var fileRegExp = new RegExp("^" + filename.replace(/[\-\[\]{}()+?.,\\\^$|#\s]/g, "\\$&").replace("*",".*") + "$");
 			var files = fs.readdirSync(path.resolve(path.dirname(recipeLine.contextPath),filedir));
 			for(var f=0; f<files.length; f++) {
 				if(fileRegExp.test(files[f])) {
@@ -341,7 +341,7 @@ Recipe.tiddlerOutputter = {
 		// Lines starting with //# are removed from javascript tiddlers
 		for(var t=0; t<tiddlers.length; t++) {
 			var tid = this.store.getTiddler(tiddlers[t]),
-				text = tid.fields.text;
+				text = tid.text;
 			// For compatibility with cook.rb, remove one trailing \n from tiddler
 			text = text.charAt(text.length-1) === "\n" ? text.substr(0,text.length-1) : text;
 			var lines = text.split("\n");
@@ -370,7 +370,7 @@ Recipe.tiddlerOutputter = {
 				tid = this.store.getTiddler(title);
 			out.push("<" + "script type=\"application/javascript\">");
 			out.push("define(\"" + title + "\",function(require,exports,module) {");
-			out.push(tid.fields.text);
+			out.push(tid.text);
 			out.push("});");
 			out.push("</" + "script>");
 		}
@@ -388,24 +388,24 @@ Recipe.prototype.cookRss = function() {
 			return title.indexOf(" ") == -1 ? title : "[[" + title + "]]";
 		},
 		tiddlerToRssItem = function(tiddler,uri) {
-			var s = "<title" + ">" + utils.htmlEncode(tiddler.fields.title) + "</title" + ">\n";
-			s += "<description>" + utils.htmlEncode(me.store.renderTiddler("text/html",tiddler.fields.title)) + "</description>\n";
+			var s = "<title" + ">" + utils.htmlEncode(tiddler.title) + "</title" + ">\n";
+			s += "<description>" + utils.htmlEncode(me.store.renderTiddler("text/html",tiddler.title)) + "</description>\n";
 			var i;
-			if(tiddler.fields.tags) {
-				for(i=0; i<tiddler.fields.tags.length; i++) {
-					s += "<category>" + tiddler.fields.tags[i] + "</category>\n";
+			if(tiddler.tags) {
+				for(i=0; i<tiddler.tags.length; i++) {
+					s += "<category>" + tiddler.tags[i] + "</category>\n";
 				}
 			}
-			s += "<link>" + uri + "#" + encodeURIComponent(encodeTiddlyLink(tiddler.fields.title)) + "</link>\n";
-			if(tiddler.fields.modified) {
-				s +="<pubDate>" + tiddler.fields.modified.toUTCString() + "</pubDate>\n";
+			s += "<link>" + uri + "#" + encodeURIComponent(encodeTiddlyLink(tiddler.title)) + "</link>\n";
+			if(tiddler.modified) {
+				s +="<pubDate>" + tiddler.modified.toUTCString() + "</pubDate>\n";
 			}
 			return s;
 		},
 		getRssTiddlers = function(sortField,excludeTag) {
 			var r = [];
 			me.store.forEachTiddler(sortField,excludeTag,function(title,tiddler) {
-				if(!tiddler.hasTag(excludeTag) && tiddler.fields.modified !== undefined) {
+				if(!tiddler.hasTag(excludeTag) && tiddler.modified !== undefined) {
 					r.push(tiddler);
 				}
 			});
diff --git a/js/SVGParser.js b/js/SVGParser.js
index d2d95c09a..0aac9f5d2 100644
--- a/js/SVGParser.js
+++ b/js/SVGParser.js
@@ -16,7 +16,7 @@ var SVGParseTree = function() {
 
 SVGParseTree.prototype.compile = function(type) {
 	if(type === "text/html") {
-		return "(function (tiddler,store,utils) {return tiddler.fields.text;})";
+		return "(function (tiddler,store,utils) {return tiddler.text;})";
 	} else {
 		return null;
 	}
diff --git a/js/Tiddler.js b/js/Tiddler.js
index 48f9814e8..5e6146df7 100755
--- a/js/Tiddler.js
+++ b/js/Tiddler.js
@@ -21,25 +21,57 @@ var utils = require("./Utils.js"),
 	ArgParser = require("./ArgParser.js").ArgParser;
 
 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],
-			src = null;
+	this.cache = {}; // Expose the cache object
+	var fields = {}, // Keep the fields private, later we'll expose getters for them
+		tags, // Keep the tags separately because they're the only Array field
+		f,t,c,arg,src;
+	// Accumulate the supplied fields
+	for(c=0; c<arguments.length; c++) {
+		arg = arguments[c];
+		src = null;
 		if(arg instanceof Tiddler) {
 			src = arg.fields;
 		} else {
 			src = arg;
 		}
-		for(var t in src) {
-			var f = this.parseTiddlerField(t,src[t]);
+		for(t in src) {
+			f = Tiddler.parseTiddlerField(t,src[t]);
 			if(f !== null) {
-				this.fields[t] = f;
+				fields[t] = f;
 			}
 		}
 	}
+	// Pull out the tags
+	if(fields.tags) {
+		tags = fields.tags;
+		delete fields.tags;
+	}
+	// Expose the fields as read only properties
+	for(f in fields) {
+		Object.defineProperty(this,f,{value: fields[f], writeable: false});
+	}
+	// Expose the tags as a getter
+	Object.defineProperty(this,"tags",{get: function() {return tags ? tags.slice(0) : [];}});
+	// Other methods that need access to the fields
+	this.getFields = function() {
+		var r = {};
+		for(var f in fields) {
+			var v = fields[f];
+			if(v instanceof Array) {
+				r[f] = v.slice(0);
+			} else {
+				r[f] = v;
+			}
+		}
+		if(tags) {
+			r.tags = tags;
+		}
+		return r;
+	};
+};
+
+Tiddler.prototype.hasTag = function(tag) {
+	return this.tags.indexOf(tag) !== -1;
 };
 
 Tiddler.standardFields = {
@@ -57,18 +89,21 @@ Tiddler.isStandardField = function(name) {
 	return name in Tiddler.standardFields;
 };
 
-Tiddler.prototype.hasTag = function(tag) {
-	if(this.tags) {
-		for(var t=0; t<this.tags.length; t++) {
-			if(this.tags[t] === tag) {
-				return true;
-			}
+Tiddler.compareTiddlerFields = function(a,b,sortField) {
+	var aa = a[sortField] || 0,
+		bb = b[sortField] || 0;
+	if(aa < bb) {
+		return -1;
+	} else {
+		if(aa > bb) {
+			return 1;
+		} else {
+			return 0;
 		}
 	}
-	return false;
 };
 
-Tiddler.prototype.parseTiddlerField = function(name,value) {
+Tiddler.parseTiddlerField = function(name,value) {
 	var type = Tiddler.specialTiddlerFields[name];
 	if(type) {
 		return Tiddler.specialTiddlerFieldParsers[type](value);
diff --git a/js/TiddlerOutput.js b/js/TiddlerOutput.js
index 9af6efcdd..15e92a821 100755
--- a/js/TiddlerOutput.js
+++ b/js/TiddlerOutput.js
@@ -34,29 +34,30 @@ var outputTiddler = function(tid) {
 	var result = [],
 		outputAttribute = function(name,value) {
 		result.push(name + ": " + value + "\n");
-	};
-	for(var t in tid.fields) {
+	},
+		fields = tid.getFields();
+	for(var t in fields) {
 		switch(t) {
 			case "text":
 				// Ignore the text field
 				break;
 			case "tags":
 				// Output tags as a list
-				outputAttribute(t,tiddlerOutput.stringifyTags(tid.fields.tags));
+				outputAttribute(t,tiddlerOutput.stringifyTags(fields.tags));
 				break;
 			case "modified":
 			case "created":
 				// Output dates in YYYYMMDDHHMM
-				outputAttribute(t,utils.convertToYYYYMMDDHHMM(tid.fields[t]));
+				outputAttribute(t,utils.convertToYYYYMMDDHHMM(fields[t]));
 				break;
 			default:
 				// Output other attributes raw
-				outputAttribute(t,tid.fields[t]);
+				outputAttribute(t,fields[t]);
 				break;
 		}
 	}
 	result.push("\n");
-	result.push(tid.fields.text);
+	result.push(fields.text);
 	return result.join("");
 };
 
@@ -68,23 +69,19 @@ The fields are in the order title, creator, modifier, created, modified, tags, f
 */
 var outputTiddlerDiv = function(tid) {
 	var result = [],
-		attributes = {},
-		outputAttribute = function(name,transform,dontDelete) {
-			if(name in attributes) {
-				var value = attributes[name];
+		fields = tid.getFields(),
+		text = fields.text,
+		outputAttribute = function(name,transform) {
+			if(name in fields) {
+				var value = fields[name];
 				if(transform)
 					value = transform(value);
 				result.push(" " + name + "=\"" + value + "\"");
-				if(!dontDelete) {
-					delete attributes[name];
-				}
+				delete fields[name];
 			}
 		};
-	for(var t in tid.fields) {
-		attributes[t] = tid.fields[t];
-	}
-	if(attributes.text) {
-		delete attributes.text;
+	if(fields.text) {
+		delete fields.text;
 	}
 	result.push("<div");
 	// Output the standard attributes in the correct order
@@ -95,11 +92,11 @@ var outputTiddlerDiv = function(tid) {
 	outputAttribute("modified", function(v) {return utils.convertToYYYYMMDDHHMM(v);});
 	outputAttribute("tags", function(v) {return stringifyTags(v);});
 	// Output any other attributes
-	for(t in attributes) {
+	for(var t in fields) {
 		outputAttribute(t,null,true);
 	}
 	result.push(">\n<pre>");
-	result.push(utils.htmlEncode(tid.fields.text));
+	result.push(utils.htmlEncode(text));
 	result.push("</pre>\n</div>");
 	return result.join("");
 };
diff --git a/js/WikiStore.js b/js/WikiStore.js
index 7d8306554..a4c9951e0 100755
--- a/js/WikiStore.js
+++ b/js/WikiStore.js
@@ -1,6 +1,12 @@
 /*\
 title: js/WikiStore.js
 
+WikiStore uses the .cache member of tiddlers to store the following information:
+
+	parseTree: Caches the parse tree for the tiddler
+	renderers: Caches rendering functions for this tiddler (indexed by MIME type)
+	renditions: Caches the renditions produced by those functions (indexed by MIME type)
+
 \*/
 (function(){
 
@@ -125,7 +131,7 @@ WikiStore.prototype.getTiddler = function(title) {
 
 WikiStore.prototype.getTiddlerText = function(title) {
 	var t = this.getTiddler(title);
-	return t instanceof Tiddler ? t.fields.text : null;
+	return t instanceof Tiddler ? t.text : null;
 };
 
 WikiStore.prototype.deleteTiddler = function(title) {
@@ -143,8 +149,8 @@ WikiStore.prototype.tiddlerExists = function(title) {
 };
 
 WikiStore.prototype.addTiddler = function(tiddler) {
-	this.tiddlers[tiddler.fields.title] = tiddler;
-	this.touchTiddler("modified",tiddler.fields.title);
+	this.tiddlers[tiddler.title] = tiddler;
+	this.touchTiddler("modified",tiddler.title);
 };
 
 WikiStore.prototype.forEachTiddler = function(/* [sortField,[excludeTag,]]callback */) {
@@ -159,22 +165,10 @@ WikiStore.prototype.forEachTiddler = function(/* [sortField,[excludeTag,]]callba
 		for(t in this.tiddlers) {
 			tiddlers.push(this.tiddlers[t]); 
 		}
-		tiddlers.sort(function (a,b) {
-			var aa = a.fields[sortField] || 0,
-				bb = b.fields[sortField] || 0;
-			if(aa < bb) {
-				return -1;
-			} else {
-				if(aa > bb) {
-					return 1;
-				} else {
-					return 0;
-				}
-			}
-		});
+		tiddlers.sort(function (a,b) {return Tiddler.compareTiddlerFields(a,b,sortField);});
 		for(t=0; t<tiddlers.length; t++) {
 			if(!tiddlers[t].hasTag(excludeTag)) {
-				callback.call(this,tiddlers[t].fields.title,tiddlers[t]);
+				callback.call(this,tiddlers[t].title,tiddlers[t]);
 			}
 		}
 	} else {
@@ -286,10 +280,10 @@ WikiStore.prototype.parseTiddler = function(title) {
 	var tiddler = this.getTiddler(title);
 	if(tiddler) {
 		// Check the cache
-		if(!tiddler.parseTree) {
-			tiddler.parseTree = this.parseText(tiddler.fields.type,tiddler.fields.text);
+		if(!tiddler.cache.parseTree) {
+			tiddler.cache.parseTree = this.parseText(tiddler.type,tiddler.text);
 		}
-		return tiddler.parseTree;
+		return tiddler.cache.parseTree;
 	} else {
 		return null;
 	}
@@ -311,11 +305,14 @@ 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));
+		if(!tiddler.cache.renderers) {
+			tiddler.cache.renderers = {};
 		}
-		return tiddler.renderers[type];
+		if(!tiddler.cache.renderers[type]) {
+			var tree = this.parseTiddler(title);
+			tiddler.cache.renderers[type] = eval(tree.compile(type));
+		}
+		return tiddler.cache.renderers[type];
 	} else {
 		return null;	
 	}
@@ -343,10 +340,13 @@ WikiStore.prototype.renderTiddler = function(targetType,title,asTitle) {
 			var asTiddler = this.getTiddler(asTitle);
 			return fn(asTiddler,this,utils);
 		} else {
-			if(!tiddler.renditions[targetType]) {
-				tiddler.renditions[targetType] = fn(tiddler,this,utils);
+			if(!tiddler.cache.renditions) {
+				tiddler.cache.renditions = {};
 			}
-			return tiddler.renditions[targetType];
+			if(!tiddler.cache.renditions[targetType]) {
+				tiddler.cache.renditions[targetType] = fn(tiddler,this,utils);
+			}
+			return tiddler.cache.renditions[targetType];
 		}
 	}
 	return null;
diff --git a/js/macros/info.js b/js/macros/info.js
index 0815b0132..028ce06d4 100644
--- a/js/macros/info.js
+++ b/js/macros/info.js
@@ -16,7 +16,7 @@ exports.macro = {
 	},
 	handler: function(type,tiddler,store,params) {
 		var encoder = type === "text/html" ? utils.htmlEncode : function(x) {return x;},
-			parseTree = store.parseTiddler(tiddler.fields.title);
+			parseTree = store.parseTiddler(tiddler.title);
 		if(parseTree) {
 			var r = [];
 			var d = parseTree.dependencies;
diff --git a/js/macros/list.js b/js/macros/list.js
index 78d1f27fb..65d5a0e1e 100644
--- a/js/macros/list.js
+++ b/js/macros/list.js
@@ -52,8 +52,8 @@ exports.macro = {
 			handler,
 			t;
 		if(template) {
-			templateType = template.fields.type;
-			templateText = template.fields.text;
+			templateType = template.type;
+			templateText = template.text;
 		}
 		handler = handlers[params.type];
 		handler = handler || handlers.all;
diff --git a/js/macros/tiddler.js b/js/macros/tiddler.js
index 1b09b7ae9..ce20fa082 100644
--- a/js/macros/tiddler.js
+++ b/js/macros/tiddler.js
@@ -21,13 +21,13 @@ exports.macro = {
 		if(params["with"]) {
 			// Parameterised transclusion
 			var targetTiddler = store.getTiddler(params.target),
-				text = targetTiddler.fields.text;
+				text = targetTiddler.text;
 			var withTokens = [params["with"]];
 			for(var t=0; t<withTokens.length; t++) {
 				var placeholderRegExp = new RegExp("\\$"+(t+1),"mg");
 				text = text.replace(placeholderRegExp,withTokens[t]);
 			}
-			return store.renderText(targetTiddler.fields.type,text,type,tiddler.fields.title);
+			return store.renderText(targetTiddler.type,text,type,tiddler.title);
 		} else {
 			// There's no parameterisation, so we can just render the target tiddler directly
 			return store.renderTiddler(type,params.target);
diff --git a/js/macros/view.js b/js/macros/view.js
index 8e4f160be..8270add7c 100644
--- a/js/macros/view.js
+++ b/js/macros/view.js
@@ -18,14 +18,14 @@ exports.macro = {
 		template: {byPos: 2, type: "text", optional: true}
 	},
 	handler: function(type,tiddler,store,params) {
-		var v = tiddler.fields[params.field],
+		var v = tiddler[params.field],
 			encoder = type === "text/html" ? utils.htmlEncode : function(x) {return x;};
 		if(v) {
 			switch(params.format) {
 				case "link":
 					return store.renderMacro("link",type,tiddler,{target: v},encoder(v));
 				case "wikified":
-					return store.renderTiddler(type,tiddler.fields.title);
+					return store.renderTiddler(type,tiddler.title);
 				case "date":
 					var template = params.template || "DD MMM YYYY";
 					return encoder(utils.formatDateString(v,template));
diff --git a/test/wikitests/SeventhTiddler.tid b/test/wikitests/SeventhTiddler.tid
index 12aa1d8be..78f640612 100644
--- a/test/wikitests/SeventhTiddler.tid
+++ b/test/wikitests/SeventhTiddler.tid
@@ -2,6 +2,6 @@ title: SeventhTiddler
 
 <<echo {{2+2}}>>
 
-<<echo {{tiddler.fields.title}}>>
+<<echo {{tiddler.title}}>>
 
 <<echo {{"window"}}>>
diff --git a/tiddlywiki.js b/tiddlywiki.js
index e166f138b..a2b1c3de6 100644
--- a/tiddlywiki.js
+++ b/tiddlywiki.js
@@ -135,7 +135,7 @@ var commandLineSwitches = {
 		handler: function(args,callback) {
 			var recipe = [];
 			app.store.forEachTiddler(function(title,tiddler) {
-				var filename = encodeURIComponent(tiddler.fields.title.replace(/ /g,"_")) + ".tid";
+				var filename = encodeURIComponent(tiddler.title.replace(/ /g,"_")) + ".tid";
 				fs.writeFileSync(path.resolve(args[0],filename),tiddlerOutput.outputTiddler(tiddler),"utf8");
 				recipe.push("tiddler: " + filename + "\n");
 			});