Bug 580508 - nsURLHelper.cpp net_ParseFileURL is asserting on resource:// URLs that are aliased to other resource:// URLs [r=jduell]

netwerk/protocol/res/nsResProtocolHandler.cpp

@@ -411,9 +411,27 @@ nsResProtocolHandler::SetSubstitution(const nsACString& root, nsIURI *baseURI)
         return NS_OK;
     }
 
+    // If baseURI isn't a resource URI, we can set the substitution immediately.
+    nsCAutoString scheme;
+    nsresult rv = baseURI->GetScheme(scheme);
+    NS_ENSURE_SUCCESS(rv, rv);
+    if (!scheme.Equals(NS_LITERAL_CSTRING("resource"))) {
         return mSubstitutions.Put(root, baseURI) ? NS_OK : NS_ERROR_UNEXPECTED;
     }
 
+    // baseURI is a resource URI, let's resolve it first.
+    nsCAutoString newBase;
+    rv = ResolveURI(baseURI, newBase);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    nsCOMPtr<nsIURI> newBaseURI;
+    rv = mIOService->NewURI(newBase, nsnull, nsnull,
+                            getter_AddRefs(newBaseURI));
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    return mSubstitutions.Put(root, newBaseURI) ? NS_OK : NS_ERROR_UNEXPECTED;
+}
+
 NS_IMETHODIMP
 nsResProtocolHandler::GetSubstitution(const nsACString& root, nsIURI **result)
 {

netwerk/test/unit/test_bug580508.js

@@ -0,0 +1,29 @@
+const Cc = Components.classes;
+const Ci = Components.interfaces;
+
+let ioService = Cc["@mozilla.org/network/io-service;1"]
+                .getService(Ci.nsIIOService);
+let resProt = ioService.getProtocolHandler("resource")
+              .QueryInterface(Ci.nsIResProtocolHandler);
+
+function run_test() {
+    // Define a resource:// alias that points to another resource:// URI.
+    let greModulesURI = ioService.newURI("resource://gre/modules/", null, null);
+    resProt.setSubstitution("my-gre-modules", greModulesURI);
+
+    // When we ask for the alias, we should not get the resource://
+    // URI that we registered it for but the original file URI.
+    let greFileSpec = ioService.newURI("modules/", null,
+                                       resProt.getSubstitution("gre")).spec;
+    let aliasURI = resProt.getSubstitution("my-gre-modules");
+    do_check_eq(aliasURI.spec, greFileSpec);
+
+    // Resolving URIs using the original resource path and the alias
+    // should yield the same result.
+    let greNetUtilURI = ioService.newURI("resource://gre/modules/NetUtil.jsm",
+                                         null, null);
+    let myNetUtilURI = ioService.newURI("resource://my-gre-modules/NetUtil.jsm",
+                                        null, null);
+    do_check_eq(resProt.resolveURI(greNetUtilURI),
+                resProt.resolveURI(myNetUtilURI));
+}