From a92ff749b30df71111a7d85eb383f28d086c6732 Mon Sep 17 00:00:00 2001
From: Steve Orvell <steve@orvellia.com>
Date: Fri, 23 Aug 2013 12:22:00 -0700
Subject: [PATCH] Improve relative path resolution; fixes issue #31

---
 src/HTMLImports.js  | 26 +++++++++++++++++---------
 test/html/path.html | 12 +++++++++++-
 2 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/src/HTMLImports.js b/src/HTMLImports.js
index 3df66ba..275e14f 100644
--- a/src/HTMLImports.js
+++ b/src/HTMLImports.js
@@ -162,7 +162,7 @@ function makeDocument(resource, url) {
   doc._URL = url;
   // establish a relative path via <base>
   var base = doc.createElement('base');
-  base.setAttribute('href', document.baseURI);
+  base.setAttribute('href', document.baseURI || document.URL);
   doc.head.appendChild(base);
   // TODO(sorvell): MDV Polyfill intrusion: boostrap template polyfill
   if (window.HTMLTemplateElement && HTMLTemplateElement.bootstrap) {
@@ -293,7 +293,7 @@ var path = {
     if (this.isAbsUrl(url)) {
       return url;
     }
-    return path.makeRelPath(path.documentURL, this.resolveUrl(baseUrl, url));
+    return this.makeDocumentRelPath(this.resolveUrl(baseUrl, url));
   },
   isAbsUrl: function(url) {
     return /(^data:)|(^http[s]?:)|(^\/)/.test(url);
@@ -322,15 +322,22 @@ var path = {
     }
     return parts.join('/') + search;
   },
+  makeDocumentRelPath: function(url) {
+    // test url against document to see if we can construct a relative path
+    path.urlElt.href = url;
+    // IE does not set host if same as document
+    if (!path.urlElt.host || 
+        (path.urlElt.host === window.location.host &&
+        path.urlElt.protocol === window.location.protocol)) {
+      return this.makeRelPath(path.documentURL, path.urlElt.href);
+    } else {
+      return url;
+    }
+  },
   // make a relative path from source to target
   makeRelPath: function(source, target) {
-    var s, t;
-    s = this.compressUrl(source).split("/");
-    t = this.compressUrl(target).split("/");
-    // bail if target is not relative to source
-    if (!s.length || s[0] !== t[0]) {
-      return target;
-    }
+    var s = source.split("/");
+    var t = target.split("/");
     while (s.length && s[0] === t[0]){
       s.shift();
       t.shift();
@@ -397,6 +404,7 @@ var path = {
 };
 
 path.documentURL = path.getDocumentUrl(document);
+path.urlElt = document.createElement('a');
 
 xhr = xhr || {
   async: true,
diff --git a/test/html/path.html b/test/html/path.html
index 59dce3a..c5a99a0 100644
--- a/test/html/path.html
+++ b/test/html/path.html
@@ -12,7 +12,7 @@
       var absBase = parts.join('/');
       var l = document.createElement('link');
       l.setAttribute('rel', 'import');
-      l.href = absBase + '/imports/abs.html';
+      l.setAttribute('href', absBase + '/imports/abs.html');
       document.head.appendChild(l);
     </script>
 </head>
@@ -25,6 +25,16 @@
   url = 'http://foo/bar?baz="foo/../bar"';
   chai.assert.equal(path.compressUrl(url), url, 'query string is not counted in path compression');
 
+  url = '../foo.png';
+  chai.assert.equal(path.makeDocumentRelPath(url), url, 'document relative path correctly resolves');
+
+  url = window.location.host + '/zonk/zim/foo.png';
+  chai.assert.equal(path.makeDocumentRelPath(url), url, 'abs / url is relative to document');  
+
+  url = window.location.protocol + '//' + window.location.hostname + ':9999/zonk/zim/foo.png';
+  chai.assert.equal(path.makeDocumentRelPath(url), url, 'other host url is absolute');  
+
+
   url = '/foo/bar/baz"';
   chai.assert.equal(path.compressUrl(url), url, 'compressUrl handles url\'s starting with / as abs');
   document.addEventListener('HTMLImportsLoaded', function() {