From ea434462d22dff130682ce3351b9b235ac7f4dff Mon Sep 17 00:00:00 2001
From: Daniel Cassidy <mail@danielcassidy.me.uk>
Date: Tue, 8 Feb 2011 21:41:56 +0000
Subject: [PATCH] DocumentType.toString: Generate a valid <!DOCTYPE> string in
 all cases where the DocumentType is valid. Won't include the internal subset
 (yet). Also, if the full DOCTYPE string is already known, just return it
 immediately without all the fuss of generating one.

---
 lib/jsdom/level2/core.js | 30 +++++++++++++++++++++---------
 1 file changed, 21 insertions(+), 9 deletions(-)

diff --git a/lib/jsdom/level2/core.js b/lib/jsdom/level2/core.js
index d0f3483312..145ebdb759 100644
--- a/lib/jsdom/level2/core.js
+++ b/lib/jsdom/level2/core.js
@@ -481,16 +481,28 @@ core.DocumentType.prototype.__defineGetter__("internalSubset", function() {
 });
 
 core.DocumentType.prototype.toString = function() {
-    var dt = '<!doctype ' + this.name;
-    if (this.publicId && this.systemId) {
-        dt += 'public ' + this.publicId + ' ' + this.systemId;
-        dt = dt.toUpperCase();
+  if (this.ownerDocument._fullDT) {
+    return this.ownerDocument._fullDT;
+  }
+  
+  var dt = '<!DOCTYPE ' + this.name;
+  if (this.publicId) {
+    // Public ID may never contain double quotes, so this is always safe.
+    dt += ' PUBLIC "' + this.publicId + '" ';
+  }
+  if (!this.publicId && this.systemId) {
+    dt += ' SYSTEM '
+  }
+  if (this.systemId) {
+    // System ID may contain double quotes OR single quotes, not never both.
+    if (this.systemId.indexOf('"') > -1) {
+      dt += "'" + this.systemId + "'";
+    } else {
+      dt += '"' + this.systemId + '"';
     }
-    dt += '>';
-    if (this.ownerDocument._fullDT) {
-        dt = this.ownerDocument._fullDT;
-    }
-    return dt;
+  }
+  dt += '>';
+  return dt;
 };
 
 core.Document.prototype.importNode = function(/* Node */ importedNode,