Bug 599975 - Fire error event for images with empty string src value; r=bz

MozReview-Commit-ID: AhXiTpgG9q3

--HG--
extra : rebase_source : fe03d94a08232e90a475529746b38b27c2591ec9

dom/base/nsImageLoadingContent.cpp

@@ -757,6 +757,13 @@ nsImageLoadingContent::LoadImage(const nsAString& aNewURI,
     return NS_OK;
   }
 
+  if (aNewURI.IsEmpty()) {
+    // Cancel image requests and then fire only error event per spec.
+    CancelImageRequests(aNotify);
+    FireEvent(NS_LITERAL_STRING("error"));
+    return NS_OK;
+  }
+
   // Second, parse the URI string to get image URI
   nsCOMPtr<nsIURI> imageURI;
   nsresult rv = StringToURI(aNewURI, doc, getter_AddRefs(imageURI));
@@ -768,24 +775,6 @@ nsImageLoadingContent::LoadImage(const nsAString& aNewURI,
     return NS_OK;
   }
 
-  bool equal;
-
-  if (aNewURI.IsEmpty() &&
-      doc->GetDocumentURI() &&
-      NS_SUCCEEDED(doc->GetDocumentURI()->EqualsExceptRef(imageURI, &equal)) &&
-      equal)  {
-
-    // Loading an embedded img from the same URI as the document URI will not work
-    // as a resource cannot recursively embed itself. Attempting to do so generally
-    // results in having to pre-emptively close down an in-flight HTTP transaction
-    // and then incurring the significant cost of establishing a new TCP channel.
-    // This is generally triggered from <img src="">
-    // In light of that, just skip loading it..
-    // Do make sure to drop our existing image, if any
-    CancelImageRequests(aNotify);
-    return NS_OK;
-  }
-
   NS_TryToSetImmutable(imageURI);
 
   return LoadImage(imageURI, aForce, aNotify, aImageLoadType, doc);

testing/web-platform/tests/html/semantics/embedded-content/the-img-element/invalid-src.html

@@ -3,10 +3,11 @@
 <title>Loading a non-parsing URL as an image should silently fail; triggering appropriate events</title>
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
-<img id=myimg />
+<img id=brokenurl />
+<img id=emptysrc />
 <script>
 async_test(function(t) {
-    var img = document.getElementById("myimg");
+    var img = document.getElementById("brokenurl");
     img.src = "http://also a broken url";
     var errorevent = false;
 
@@ -16,6 +17,26 @@ async_test(function(t) {
     img.addEventListener('loadend', t.step_func_done(function() {
         assert_true(errorevent, "error event fired");
     }));
-});
+}, 'src="http://also a broken url"');
+
+async_test(function(t) {
+    var img = document.getElementById("emptysrc");
+    img.src = "";
+    var loadendevent = false;
+
+    // Setting src to empty string triggers only error event.
+    // The errors should be queued in the event loop, so they should only trigger
+    // after this block of code finishes, not during the img.src setter itself
+    img.addEventListener('error', t.step_func(function() {
+        // Queue this check in the event loop to check there is no loadend event
+        // fired.
+        t.step_timeout(t.step_func_done(function() {
+            assert_false(loadendevent, "loadend event should not fired");
+        }), 0)
+    }));
+    img.addEventListener('loadend', t.step_func(function() {
+        loadendevent = true;
+    }));
+}, 'src=""');
 
 </script>