Add m-esr52 at 52.6.0

1 files changed, 1090 insertions, 0 deletions

diff --git a/dom/xbl/nsXBLService.cpp b/dom/xbl/nsXBLService.cpp
new file mode 100644
index 0000000000..1475b1368d
--- /dev/null
+++ b/dom/xbl/nsXBLService.cpp
@@ -0,0 +1,1090 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/ArrayUtils.h"
+
+#include "nsCOMPtr.h"
+#include "nsNetUtil.h"
+#include "nsXBLService.h"
+#include "nsXBLWindowKeyHandler.h"
+#include "nsIInputStream.h"
+#include "nsNameSpaceManager.h"
+#include "nsIURI.h"
+#include "nsIDOMElement.h"
+#include "nsIURL.h"
+#include "nsIChannel.h"
+#include "nsXPIDLString.h"
+#include "plstr.h"
+#include "nsIContent.h"
+#include "nsIDocument.h"
+#include "nsIXMLContentSink.h"
+#include "nsContentCID.h"
+#include "mozilla/dom/XMLDocument.h"
+#include "nsGkAtoms.h"
+#include "nsIMemory.h"
+#include "nsIObserverService.h"
+#include "nsIDOMNodeList.h"
+#include "nsXBLContentSink.h"
+#include "nsXBLBinding.h"
+#include "nsXBLPrototypeBinding.h"
+#include "nsXBLDocumentInfo.h"
+#include "nsCRT.h"
+#include "nsContentUtils.h"
+#include "nsSyncLoadService.h"
+#include "nsContentPolicyUtils.h"
+#include "nsTArray.h"
+#include "nsError.h"
+
+#include "nsIPresShell.h"
+#include "nsIDocumentObserver.h"
+#include "nsFrameManager.h"
+#include "nsStyleContext.h"
+#include "nsIScriptSecurityManager.h"
+#include "nsIScriptError.h"
+#include "nsXBLSerialize.h"
+
+#ifdef MOZ_XUL
+#include "nsXULPrototypeCache.h"
+#endif
+#include "nsIDOMEventListener.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/EventListenerManager.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/dom/Event.h"
+#include "mozilla/dom/Element.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+#define NS_MAX_XBL_BINDING_RECURSION 20
+
+nsXBLService* nsXBLService::gInstance = nullptr;
+
+static bool
+IsAncestorBinding(nsIDocument* aDocument,
+                  nsIURI* aChildBindingURI,
+                  nsIContent* aChild)
+{
+  NS_ASSERTION(aDocument, "expected a document");
+  NS_ASSERTION(aChildBindingURI, "expected a binding URI");
+  NS_ASSERTION(aChild, "expected a child content");
+
+  uint32_t bindingRecursion = 0;
+  for (nsIContent *bindingParent = aChild->GetBindingParent();
+       bindingParent;
+       bindingParent = bindingParent->GetBindingParent()) {
+    nsXBLBinding* binding = bindingParent->GetXBLBinding();
+    if (!binding) {
+      continue;
+    }
+
+    if (binding->PrototypeBinding()->CompareBindingURI(aChildBindingURI)) {
+      ++bindingRecursion;
+      if (bindingRecursion < NS_MAX_XBL_BINDING_RECURSION) {
+        continue;
+      }
+      NS_ConvertUTF8toUTF16 bindingURI(aChildBindingURI->GetSpecOrDefault());
+      const char16_t* params[] = { bindingURI.get() };
+      nsContentUtils::ReportToConsole(nsIScriptError::warningFlag,
+                                      NS_LITERAL_CSTRING("XBL"), aDocument,
+                                      nsContentUtils::eXBL_PROPERTIES,
+                                      "TooDeepBindingRecursion",
+                                      params, ArrayLength(params));
+      return true;
+    }
+  }
+
+  return false;
+}
+
+// Individual binding requests.
+class nsXBLBindingRequest
+{
+public:
+  nsCOMPtr<nsIURI> mBindingURI;
+  nsCOMPtr<nsIContent> mBoundElement;
+
+  void DocumentLoaded(nsIDocument* aBindingDoc)
+  {
+    // We only need the document here to cause frame construction, so
+    // we need the current doc, not the owner doc.
+    nsIDocument* doc = mBoundElement->GetUncomposedDoc();
+    if (!doc)
+      return;
+
+    // Destroy the frames for mBoundElement.
+    nsIContent* destroyedFramesFor = nullptr;
+    nsIPresShell* shell = doc->GetShell();
+    if (shell) {
+      shell->DestroyFramesFor(mBoundElement, &destroyedFramesFor);
+    }
+    MOZ_ASSERT(!mBoundElement->GetPrimaryFrame());
+
+    // Get the binding.
+    bool ready = false;
+    nsXBLService::GetInstance()->BindingReady(mBoundElement, mBindingURI, &ready);
+    if (!ready)
+      return;
+
+    // If |mBoundElement| is (in addition to having binding |mBinding|)
+    // also a descendant of another element with binding |mBinding|,
+    // then we might have just constructed it due to the
+    // notification of its parent.  (We can know about both if the
+    // binding loads were triggered from the DOM rather than frame
+    // construction.)  So we have to check both whether the element
+    // has a primary frame and whether it's in the frame manager maps
+    // before sending a ContentInserted notification, or bad things
+    // will happen.
+    MOZ_ASSERT(shell == doc->GetShell());
+    if (shell) {
+      nsIFrame* childFrame = mBoundElement->GetPrimaryFrame();
+      if (!childFrame) {
+        // Check to see if it's in the undisplayed content map...
+        nsFrameManager* fm = shell->FrameManager();
+        nsStyleContext* sc = fm->GetUndisplayedContent(mBoundElement);
+        if (!sc) {
+          // or in the display:contents map.
+          sc = fm->GetDisplayContentsStyleFor(mBoundElement);
+        }
+        if (!sc) {
+          shell->CreateFramesFor(destroyedFramesFor);
+        }
+      }
+    }
+  }
+
+  nsXBLBindingRequest(nsIURI* aURI, nsIContent* aBoundElement)
+    : mBindingURI(aURI),
+      mBoundElement(aBoundElement)
+  {
+  }
+};
+
+// nsXBLStreamListener, a helper class used for
+// asynchronous parsing of URLs
+/* Header file */
+class nsXBLStreamListener final : public nsIStreamListener,
+                                  public nsIDOMEventListener
+{
+public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSISTREAMLISTENER
+  NS_DECL_NSIREQUESTOBSERVER
+  NS_DECL_NSIDOMEVENTLISTENER
+
+  nsXBLStreamListener(nsIDocument* aBoundDocument,
+                      nsIXMLContentSink* aSink,
+                      nsIDocument* aBindingDocument);
+
+  void AddRequest(nsXBLBindingRequest* aRequest) { mBindingRequests.AppendElement(aRequest); }
+  bool HasRequest(nsIURI* aURI, nsIContent* aBoundElement);
+
+private:
+  ~nsXBLStreamListener();
+
+  nsCOMPtr<nsIStreamListener> mInner;
+  AutoTArray<nsXBLBindingRequest*, 8> mBindingRequests;
+
+  nsCOMPtr<nsIWeakReference> mBoundDocument;
+  nsCOMPtr<nsIXMLContentSink> mSink; // Only set until OnStartRequest
+  nsCOMPtr<nsIDocument> mBindingDocument; // Only set until OnStartRequest
+};
+
+/* Implementation file */
+NS_IMPL_ISUPPORTS(nsXBLStreamListener,
+                  nsIStreamListener,
+                  nsIRequestObserver,
+                  nsIDOMEventListener)
+
+nsXBLStreamListener::nsXBLStreamListener(nsIDocument* aBoundDocument,
+                                         nsIXMLContentSink* aSink,
+                                         nsIDocument* aBindingDocument)
+: mSink(aSink), mBindingDocument(aBindingDocument)
+{
+  /* member initializers and constructor code */
+  mBoundDocument = do_GetWeakReference(aBoundDocument);
+}
+
+nsXBLStreamListener::~nsXBLStreamListener()
+{
+  for (uint32_t i = 0; i < mBindingRequests.Length(); i++) {
+    nsXBLBindingRequest* req = mBindingRequests.ElementAt(i);
+    delete req;
+  }
+}
+
+NS_IMETHODIMP
+nsXBLStreamListener::OnDataAvailable(nsIRequest *request, nsISupports* aCtxt,
+                                     nsIInputStream* aInStr,
+                                     uint64_t aSourceOffset, uint32_t aCount)
+{
+  if (mInner)
+    return mInner->OnDataAvailable(request, aCtxt, aInStr, aSourceOffset, aCount);
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+nsXBLStreamListener::OnStartRequest(nsIRequest* request, nsISupports* aCtxt)
+{
+  // Make sure we don't hold on to the sink and binding document past this point
+  nsCOMPtr<nsIXMLContentSink> sink;
+  mSink.swap(sink);
+  nsCOMPtr<nsIDocument> doc;
+  mBindingDocument.swap(doc);
+
+  nsCOMPtr<nsIChannel> channel = do_QueryInterface(request);
+  NS_ENSURE_TRUE(channel, NS_ERROR_UNEXPECTED);
+
+  nsCOMPtr<nsILoadGroup> group;
+  request->GetLoadGroup(getter_AddRefs(group));
+
+  nsresult rv = doc->StartDocumentLoad("loadAsInteractiveData",
+                                       channel,
+                                       group,
+                                       nullptr,
+                                       getter_AddRefs(mInner),
+                                       true,
+                                       sink);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Make sure to add ourselves as a listener after StartDocumentLoad,
+  // since that resets the event listners on the document.
+  doc->AddEventListener(NS_LITERAL_STRING("load"), this, false);
+
+  return mInner->OnStartRequest(request, aCtxt);
+}
+
+NS_IMETHODIMP
+nsXBLStreamListener::OnStopRequest(nsIRequest* request, nsISupports* aCtxt, nsresult aStatus)
+{
+  nsresult rv = NS_OK;
+  if (mInner) {
+     rv = mInner->OnStopRequest(request, aCtxt, aStatus);
+  }
+
+  // Don't hold onto the inner listener; holding onto it can create a cycle
+  // with the document
+  mInner = nullptr;
+
+  return rv;
+}
+
+bool
+nsXBLStreamListener::HasRequest(nsIURI* aURI, nsIContent* aElt)
+{
+  // XXX Could be more efficient.
+  uint32_t count = mBindingRequests.Length();
+  for (uint32_t i = 0; i < count; i++) {
+    nsXBLBindingRequest* req = mBindingRequests.ElementAt(i);
+    bool eq;
+    if (req->mBoundElement == aElt &&
+        NS_SUCCEEDED(req->mBindingURI->Equals(aURI, &eq)) && eq)
+      return true;
+  }
+
+  return false;
+}
+
+nsresult
+nsXBLStreamListener::HandleEvent(nsIDOMEvent* aEvent)
+{
+  nsresult rv = NS_OK;
+  uint32_t i;
+  uint32_t count = mBindingRequests.Length();
+
+  // Get the binding document; note that we don't hold onto it in this object
+  // to avoid creating a cycle
+  Event* event = aEvent->InternalDOMEvent();
+  EventTarget* target = event->GetCurrentTarget();
+  nsCOMPtr<nsIDocument> bindingDocument = do_QueryInterface(target);
+  NS_ASSERTION(bindingDocument, "Event not targeted at document?!");
+
+  // See if we're still alive.
+  nsCOMPtr<nsIDocument> doc(do_QueryReferent(mBoundDocument));
+  if (!doc) {
+    NS_WARNING("XBL load did not complete until after document went away! Modal dialog bug?\n");
+  }
+  else {
+    // We have to do a flush prior to notification of the document load.
+    // This has to happen since the HTML content sink can be holding on
+    // to notifications related to our children (e.g., if you bind to the
+    // <body> tag) that result in duplication of content.
+    // We need to get the sink's notifications flushed and then make the binding
+    // ready.
+    if (count > 0) {
+      nsXBLBindingRequest* req = mBindingRequests.ElementAt(0);
+      nsIDocument* document = req->mBoundElement->GetUncomposedDoc();
+      if (document)
+        document->FlushPendingNotifications(Flush_ContentAndNotify);
+    }
+
+    // Remove ourselves from the set of pending docs.
+    nsBindingManager *bindingManager = doc->BindingManager();
+    nsIURI* documentURI = bindingDocument->GetDocumentURI();
+    bindingManager->RemoveLoadingDocListener(documentURI);
+
+    if (!bindingDocument->GetRootElement()) {
+      // FIXME: How about an error console warning?
+      NS_WARNING("XBL doc with no root element - this usually shouldn't happen");
+      return NS_ERROR_FAILURE;
+    }
+
+    // Put our doc info in the doc table.
+    nsBindingManager *xblDocBindingManager = bindingDocument->BindingManager();
+    RefPtr<nsXBLDocumentInfo> info =
+      xblDocBindingManager->GetXBLDocumentInfo(documentURI);
+    xblDocBindingManager->RemoveXBLDocumentInfo(info); // Break the self-imposed cycle.
+    if (!info) {
+      if (nsXBLService::IsChromeOrResourceURI(documentURI)) {
+        NS_WARNING("An XBL file is malformed. Did you forget the XBL namespace on the bindings tag?");
+      }
+      nsContentUtils::ReportToConsole(nsIScriptError::warningFlag,
+                                      NS_LITERAL_CSTRING("XBL"), nullptr,
+                                      nsContentUtils::eXBL_PROPERTIES,
+                                      "MalformedXBL",
+                                      nullptr, 0, documentURI);
+      return NS_ERROR_FAILURE;
+    }
+
+    // If the doc is a chrome URI, then we put it into the XUL cache.
+#ifdef MOZ_XUL
+    if (nsXBLService::IsChromeOrResourceURI(documentURI)) {
+      nsXULPrototypeCache* cache = nsXULPrototypeCache::GetInstance();
+      if (cache && cache->IsEnabled())
+        cache->PutXBLDocumentInfo(info);
+    }
+#endif
+
+    bindingManager->PutXBLDocumentInfo(info);
+
+    // Notify all pending requests that their bindings are
+    // ready and can be installed.
+    for (i = 0; i < count; i++) {
+      nsXBLBindingRequest* req = mBindingRequests.ElementAt(i);
+      req->DocumentLoaded(bindingDocument);
+    }
+  }
+
+  target->RemoveEventListener(NS_LITERAL_STRING("load"), this, false);
+
+  return rv;
+}
+
+// Implementation /////////////////////////////////////////////////////////////////
+
+// Implement our nsISupports methods
+NS_IMPL_ISUPPORTS(nsXBLService, nsISupportsWeakReference)
+
+void
+nsXBLService::Init()
+{
+  gInstance = new nsXBLService();
+  NS_ADDREF(gInstance);
+}
+
+// Constructors/Destructors
+nsXBLService::nsXBLService(void)
+{
+}
+
+nsXBLService::~nsXBLService(void)
+{
+}
+
+// static
+bool
+nsXBLService::IsChromeOrResourceURI(nsIURI* aURI)
+{
+  bool isChrome = false;
+  bool isResource = false;
+  if (NS_SUCCEEDED(aURI->SchemeIs("chrome", &isChrome)) &&
+      NS_SUCCEEDED(aURI->SchemeIs("resource", &isResource)))
+      return (isChrome || isResource);
+  return false;
+}
+
+
+// This function loads a particular XBL file and installs all of the bindings
+// onto the element.
+nsresult
+nsXBLService::LoadBindings(nsIContent* aContent, nsIURI* aURL,
+                           nsIPrincipal* aOriginPrincipal,
+                           nsXBLBinding** aBinding, bool* aResolveStyle)
+{
+  NS_PRECONDITION(aOriginPrincipal, "Must have an origin principal");
+
+  *aBinding = nullptr;
+  *aResolveStyle = false;
+
+  nsresult rv;
+
+  nsCOMPtr<nsIDocument> document = aContent->OwnerDoc();
+
+  nsAutoCString urlspec;
+  bool ok = nsContentUtils::GetWrapperSafeScriptFilename(document, aURL,
+                                                         urlspec, &rv);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  if (ok) {
+    // Block an attempt to load a binding that has special wrapper
+    // automation needs.
+    return NS_OK;
+  }
+
+  nsXBLBinding *binding = aContent->GetXBLBinding();
+  if (binding) {
+    if (binding->MarkedForDeath()) {
+      FlushStyleBindings(aContent);
+      binding = nullptr;
+    }
+    else {
+      // See if the URIs match.
+      if (binding->PrototypeBinding()->CompareBindingURI(aURL))
+        return NS_OK;
+      FlushStyleBindings(aContent);
+      binding = nullptr;
+    }
+  }
+
+  bool ready;
+  RefPtr<nsXBLBinding> newBinding;
+  if (NS_FAILED(rv = GetBinding(aContent, aURL, false, aOriginPrincipal,
+                                &ready, getter_AddRefs(newBinding)))) {
+    return rv;
+  }
+
+  if (!newBinding) {
+#ifdef DEBUG
+    nsAutoCString str(NS_LITERAL_CSTRING("Failed to locate XBL binding. XBL is now using id instead of name to reference bindings. Make sure you have switched over.  The invalid binding name is: ") + aURL->GetSpecOrDefault());
+    NS_ERROR(str.get());
+#endif
+    return NS_OK;
+  }
+
+  if (::IsAncestorBinding(document, aURL, aContent)) {
+    return NS_ERROR_ILLEGAL_VALUE;
+  }
+
+  // We loaded a style binding.  It goes on the end.
+  if (binding) {
+    // Get the last binding that is in the append layer.
+    binding->RootBinding()->SetBaseBinding(newBinding);
+  }
+  else {
+    // Install the binding on the content node.
+    aContent->SetXBLBinding(newBinding);
+  }
+
+  {
+    nsAutoScriptBlocker scriptBlocker;
+
+    // Set the binding's bound element.
+    newBinding->SetBoundElement(aContent);
+
+    // Tell the binding to build the anonymous content.
+    newBinding->GenerateAnonymousContent();
+
+    // Tell the binding to install event handlers
+    newBinding->InstallEventHandlers();
+
+    // Set up our properties
+    rv = newBinding->InstallImplementation();
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // Figure out if we have any scoped sheets.  If so, we do a second resolve.
+    *aResolveStyle = newBinding->HasStyleSheets();
+
+    newBinding.forget(aBinding);
+  }
+
+  return NS_OK;
+}
+
+nsresult
+nsXBLService::FlushStyleBindings(nsIContent* aContent)
+{
+  nsCOMPtr<nsIDocument> document = aContent->OwnerDoc();
+
+  nsXBLBinding *binding = aContent->GetXBLBinding();
+  if (binding) {
+    // Clear out the script references.
+    binding->ChangeDocument(document, nullptr);
+
+    aContent->SetXBLBinding(nullptr); // Flush old style bindings
+  }
+
+  return NS_OK;
+}
+
+//
+// AttachGlobalKeyHandler
+//
+// Creates a new key handler and prepares to listen to key events on the given
+// event receiver (either a document or an content node). If the receiver is content,
+// then extra work needs to be done to hook it up to the document (XXX WHY??)
+//
+nsresult
+nsXBLService::AttachGlobalKeyHandler(EventTarget* aTarget)
+{
+  // check if the receiver is a content node (not a document), and hook
+  // it to the document if that is the case.
+  nsCOMPtr<EventTarget> piTarget = aTarget;
+  nsCOMPtr<nsIContent> contentNode(do_QueryInterface(aTarget));
+  if (contentNode) {
+    // Only attach if we're really in a document
+    nsCOMPtr<nsIDocument> doc = contentNode->GetUncomposedDoc();
+    if (doc)
+      piTarget = doc; // We're a XUL keyset. Attach to our document.
+  }
+
+  if (!piTarget)
+    return NS_ERROR_FAILURE;
+
+  EventListenerManager* manager = piTarget->GetOrCreateListenerManager();
+  if (!manager)
+    return NS_ERROR_FAILURE;
+
+  // the listener already exists, so skip this
+  if (contentNode && contentNode->GetProperty(nsGkAtoms::listener))
+    return NS_OK;
+
+  nsCOMPtr<nsIDOMElement> elt(do_QueryInterface(contentNode));
+
+  // Create the key handler
+  RefPtr<nsXBLWindowKeyHandler> handler =
+    NS_NewXBLWindowKeyHandler(elt, piTarget);
+
+  handler->InstallKeyboardEventListenersTo(manager);
+
+  if (contentNode)
+    return contentNode->SetProperty(nsGkAtoms::listener,
+                                    handler.forget().take(),
+                                    nsPropertyTable::SupportsDtorFunc, true);
+
+  // The reference to the handler will be maintained by the event target,
+  // and, if there is a content node, the property.
+  return NS_OK;
+}
+
+//
+// DetachGlobalKeyHandler
+//
+// Removes a key handler added by DeatchGlobalKeyHandler.
+//
+nsresult
+nsXBLService::DetachGlobalKeyHandler(EventTarget* aTarget)
+{
+  nsCOMPtr<EventTarget> piTarget = aTarget;
+  nsCOMPtr<nsIContent> contentNode(do_QueryInterface(aTarget));
+  if (!contentNode) // detaching is only supported for content nodes
+    return NS_ERROR_FAILURE;
+
+  // Only attach if we're really in a document
+  nsCOMPtr<nsIDocument> doc = contentNode->GetUncomposedDoc();
+  if (doc)
+    piTarget = do_QueryInterface(doc);
+
+  if (!piTarget)
+    return NS_ERROR_FAILURE;
+
+  EventListenerManager* manager = piTarget->GetOrCreateListenerManager();
+  if (!manager)
+    return NS_ERROR_FAILURE;
+
+  nsIDOMEventListener* handler =
+    static_cast<nsIDOMEventListener*>(contentNode->GetProperty(nsGkAtoms::listener));
+  if (!handler)
+    return NS_ERROR_FAILURE;
+
+  static_cast<nsXBLWindowKeyHandler*>(handler)->
+    RemoveKeyboardEventListenersFrom(manager);
+
+  contentNode->DeleteProperty(nsGkAtoms::listener);
+
+  return NS_OK;
+}
+
+// Internal helper methods ////////////////////////////////////////////////////////////////
+
+nsresult
+nsXBLService::BindingReady(nsIContent* aBoundElement,
+                           nsIURI* aURI,
+                           bool* aIsReady)
+{
+  // Don't do a security check here; we know this binding is set to go.
+  return GetBinding(aBoundElement, aURI, true, nullptr, aIsReady, nullptr);
+}
+
+nsresult
+nsXBLService::GetBinding(nsIContent* aBoundElement, nsIURI* aURI,
+                         bool aPeekOnly, nsIPrincipal* aOriginPrincipal,
+                         bool* aIsReady, nsXBLBinding** aResult)
+{
+  // More than 6 binding URIs are rare, see bug 55070 comment 18.
+  AutoTArray<nsCOMPtr<nsIURI>, 6> uris;
+  return GetBinding(aBoundElement, aURI, aPeekOnly, aOriginPrincipal, aIsReady,
+                    aResult, uris);
+}
+
+static bool
+MayBindToContent(nsXBLPrototypeBinding* aProtoBinding, nsIContent* aBoundElement,
+                 nsIURI* aURI)
+{
+  // If this binding explicitly allows untrusted content, we're done.
+  if (aProtoBinding->BindToUntrustedContent()) {
+    return true;
+  }
+
+  // We let XUL content and content in XUL documents through, since XUL is
+  // restricted anyway and we want to minimize remote XUL breakage.
+  if (aBoundElement->IsXULElement() ||
+      aBoundElement->OwnerDoc()->IsXULElement()) {
+    return true;
+  }
+
+  // Similarly, we make an exception for anonymous content (which
+  // lives in the XBL scope), because it's already protected from content,
+  // and tends to use a lot of bindings that we wouldn't otherwise need to
+  // whitelist.
+  if (aBoundElement->IsInAnonymousSubtree()) {
+    return true;
+  }
+
+  // Allow if the bound content subsumes the binding.
+  nsCOMPtr<nsIDocument> bindingDoc = aProtoBinding->XBLDocumentInfo()->GetDocument();
+  NS_ENSURE_TRUE(bindingDoc, false);
+  if (aBoundElement->NodePrincipal()->Subsumes(bindingDoc->NodePrincipal())) {
+    return true;
+  }
+
+  // One last special case: we need to watch out for in-document data: URI
+  // bindings from remote-XUL-whitelisted domains (especially tests), because
+  // they end up with a null principal (rather than inheriting the document's
+  // principal), which causes them to fail the check above.
+  if (nsContentUtils::AllowXULXBLForPrincipal(aBoundElement->NodePrincipal())) {
+    bool isDataURI = false;
+    nsresult rv = aURI->SchemeIs("data", &isDataURI);
+    NS_ENSURE_SUCCESS(rv, false);
+    if (isDataURI) {
+      return true;
+    }
+  }
+
+  // Disallow.
+  return false;
+}
+
+nsresult
+nsXBLService::GetBinding(nsIContent* aBoundElement, nsIURI* aURI,
+                         bool aPeekOnly, nsIPrincipal* aOriginPrincipal,
+                         bool* aIsReady, nsXBLBinding** aResult,
+                         nsTArray<nsCOMPtr<nsIURI>>& aDontExtendURIs)
+{
+  NS_ASSERTION(aPeekOnly || aResult,
+               "Must have non-null out param if not just peeking to see "
+               "whether the binding is ready");
+
+  if (aResult)
+    *aResult = nullptr;
+
+  if (!aURI)
+    return NS_ERROR_FAILURE;
+
+  nsAutoCString ref;
+  aURI->GetRef(ref);
+
+  nsCOMPtr<nsIDocument> boundDocument = aBoundElement->OwnerDoc();
+
+  RefPtr<nsXBLDocumentInfo> docInfo;
+  nsresult rv = LoadBindingDocumentInfo(aBoundElement, boundDocument, aURI,
+                                        aOriginPrincipal,
+                                        false, getter_AddRefs(docInfo));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (!docInfo)
+    return NS_ERROR_FAILURE;
+
+  WeakPtr<nsXBLPrototypeBinding> protoBinding =
+    docInfo->GetPrototypeBinding(ref);
+
+  if (!protoBinding) {
+#ifdef DEBUG
+    nsAutoCString message("Unable to locate an XBL binding for URI ");
+    message += aURI->GetSpecOrDefault();
+    message += " in document ";
+    message += boundDocument->GetDocumentURI()->GetSpecOrDefault();
+    NS_WARNING(message.get());
+#endif
+    return NS_ERROR_FAILURE;
+  }
+
+  // If the binding isn't whitelisted, refuse to apply it to content that
+  // doesn't subsume it (modulo a few exceptions).
+  if (!MayBindToContent(protoBinding, aBoundElement, aURI)) {
+#ifdef DEBUG
+    nsAutoCString message("Permission denied to apply binding ");
+    message += aURI->GetSpecOrDefault();
+    message += " to unprivileged content. Set bindToUntrustedContent=true on "
+               "the binding to override this restriction.";
+    NS_WARNING(message.get());
+#endif
+   return NS_ERROR_FAILURE;
+  }
+
+  aDontExtendURIs.AppendElement(protoBinding->BindingURI());
+  nsCOMPtr<nsIURI> altBindingURI = protoBinding->AlternateBindingURI();
+  if (altBindingURI) {
+    aDontExtendURIs.AppendElement(altBindingURI);
+  }
+
+  // Our prototype binding must have all its resources loaded.
+  bool ready = protoBinding->LoadResources();
+  if (!ready) {
+    // Add our bound element to the protos list of elts that should
+    // be notified when the stylesheets and scripts finish loading.
+    protoBinding->AddResourceListener(aBoundElement);
+    return NS_ERROR_FAILURE; // The binding isn't ready yet.
+  }
+
+  rv = protoBinding->ResolveBaseBinding();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIURI> baseBindingURI;
+  WeakPtr<nsXBLPrototypeBinding> baseProto = protoBinding->GetBasePrototype();
+  if (baseProto) {
+    baseBindingURI = baseProto->BindingURI();
+  }
+  else {
+    baseBindingURI = protoBinding->GetBaseBindingURI();
+    if (baseBindingURI) {
+      uint32_t count = aDontExtendURIs.Length();
+      for (uint32_t index = 0; index < count; ++index) {
+        bool equal;
+        rv = aDontExtendURIs[index]->Equals(baseBindingURI, &equal);
+        NS_ENSURE_SUCCESS(rv, rv);
+        if (equal) {
+          NS_ConvertUTF8toUTF16
+            protoSpec(protoBinding->BindingURI()->GetSpecOrDefault());
+          NS_ConvertUTF8toUTF16 baseSpec(baseBindingURI->GetSpecOrDefault());
+          const char16_t* params[] = { protoSpec.get(), baseSpec.get() };
+          nsContentUtils::ReportToConsole(nsIScriptError::warningFlag,
+                                          NS_LITERAL_CSTRING("XBL"), nullptr,
+                                          nsContentUtils::eXBL_PROPERTIES,
+                                          "CircularExtendsBinding",
+                                          params, ArrayLength(params),
+                                          boundDocument->GetDocumentURI());
+          return NS_ERROR_ILLEGAL_VALUE;
+        }
+      }
+    }
+  }
+
+  RefPtr<nsXBLBinding> baseBinding;
+  if (baseBindingURI) {
+    nsCOMPtr<nsIContent> child = protoBinding->GetBindingElement();
+    rv = GetBinding(aBoundElement, baseBindingURI, aPeekOnly,
+                    child->NodePrincipal(), aIsReady,
+                    getter_AddRefs(baseBinding), aDontExtendURIs);
+    if (NS_FAILED(rv))
+      return rv; // We aren't ready yet.
+  }
+
+  *aIsReady = true;
+
+  if (!aPeekOnly) {
+    // Make a new binding
+    NS_ENSURE_STATE(protoBinding);
+    nsXBLBinding *newBinding = new nsXBLBinding(protoBinding);
+
+    if (baseBinding) {
+      if (!baseProto) {
+        protoBinding->SetBasePrototype(baseBinding->PrototypeBinding());
+      }
+       newBinding->SetBaseBinding(baseBinding);
+    }
+
+    NS_ADDREF(*aResult = newBinding);
+  }
+
+  return NS_OK;
+}
+
+static bool
+IsSystemOrChromeURLPrincipal(nsIPrincipal* aPrincipal)
+{
+  if (nsContentUtils::IsSystemPrincipal(aPrincipal)) {
+    return true;
+  }
+
+  nsCOMPtr<nsIURI> uri;
+  aPrincipal->GetURI(getter_AddRefs(uri));
+  NS_ENSURE_TRUE(uri, false);
+
+  bool isChrome = false;
+  return NS_SUCCEEDED(uri->SchemeIs("chrome", &isChrome)) && isChrome;
+}
+
+nsresult
+nsXBLService::LoadBindingDocumentInfo(nsIContent* aBoundElement,
+                                      nsIDocument* aBoundDocument,
+                                      nsIURI* aBindingURI,
+                                      nsIPrincipal* aOriginPrincipal,
+                                      bool aForceSyncLoad,
+                                      nsXBLDocumentInfo** aResult)
+{
+  NS_PRECONDITION(aBindingURI, "Must have a binding URI");
+  NS_PRECONDITION(!aOriginPrincipal || aBoundDocument,
+                  "If we're doing a security check, we better have a document!");
+
+  *aResult = nullptr;
+  // Allow XBL in unprivileged documents if it's specified in a privileged or
+  // chrome: stylesheet. This allows themes to specify XBL bindings.
+  if (aOriginPrincipal && !IsSystemOrChromeURLPrincipal(aOriginPrincipal)) {
+    NS_ENSURE_TRUE(!aBoundDocument || aBoundDocument->AllowXULXBL(),
+                   NS_ERROR_XBL_BLOCKED);
+  }
+
+  RefPtr<nsXBLDocumentInfo> info;
+
+  nsCOMPtr<nsIURI> documentURI;
+  nsresult rv = aBindingURI->CloneIgnoringRef(getter_AddRefs(documentURI));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsBindingManager *bindingManager = nullptr;
+
+  // The first thing to check is the binding manager, which (if it exists)
+  // should have a reference to the nsXBLDocumentInfo if this document
+  // has ever loaded this binding before.
+  if (aBoundDocument) {
+    bindingManager = aBoundDocument->BindingManager();
+    info = bindingManager->GetXBLDocumentInfo(documentURI);
+    if (aBoundDocument->IsStaticDocument() &&
+        IsChromeOrResourceURI(aBindingURI)) {
+      aForceSyncLoad = true;
+    }
+  }
+
+  // It's possible the document is already being loaded. If so, there's no
+  // document yet, but we need to glom on our request so that it will be
+  // processed whenever the doc does finish loading.
+  NodeInfo *ni = nullptr;
+  if (aBoundElement)
+    ni = aBoundElement->NodeInfo();
+
+  if (!info && bindingManager &&
+      (!ni || !(ni->Equals(nsGkAtoms::scrollbar, kNameSpaceID_XUL) ||
+                ni->Equals(nsGkAtoms::thumb, kNameSpaceID_XUL) ||
+                ((ni->Equals(nsGkAtoms::input) ||
+                  ni->Equals(nsGkAtoms::select)) &&
+                 aBoundElement->IsHTMLElement()))) && !aForceSyncLoad) {
+    nsCOMPtr<nsIStreamListener> listener;
+    if (bindingManager)
+      listener = bindingManager->GetLoadingDocListener(documentURI);
+    if (listener) {
+      nsXBLStreamListener* xblListener =
+        static_cast<nsXBLStreamListener*>(listener.get());
+      // Create a new load observer.
+      if (!xblListener->HasRequest(aBindingURI, aBoundElement)) {
+        nsXBLBindingRequest* req = new nsXBLBindingRequest(aBindingURI, aBoundElement);
+        xblListener->AddRequest(req);
+      }
+      return NS_OK;
+    }
+  }
+
+#ifdef MOZ_XUL
+  // The second line of defense is the global nsXULPrototypeCache,
+  // if it's being used.
+  nsXULPrototypeCache* cache = nsXULPrototypeCache::GetInstance();
+  bool useXULCache = cache && cache->IsEnabled();
+
+  if (!info && useXULCache) {
+    // This cache crosses the entire product, so that any XBL bindings that are
+    // part of chrome will be reused across all XUL documents.
+    info = cache->GetXBLDocumentInfo(documentURI);
+  }
+
+  bool useStartupCache = useXULCache && IsChromeOrResourceURI(documentURI);
+
+  if (!info) {
+    // Next, look in the startup cache
+    if (!info && useStartupCache) {
+      rv = nsXBLDocumentInfo::ReadPrototypeBindings(documentURI, getter_AddRefs(info));
+      if (NS_SUCCEEDED(rv)) {
+        cache->PutXBLDocumentInfo(info);
+      }
+    }
+  }
+#endif
+
+  if (!info) {
+    // Finally, if all lines of defense fail, we go and fetch the binding
+    // document.
+
+    // Always load chrome synchronously
+    bool chrome;
+    if (NS_SUCCEEDED(documentURI->SchemeIs("chrome", &chrome)) && chrome)
+      aForceSyncLoad = true;
+
+    nsCOMPtr<nsIDocument> document;
+    rv = FetchBindingDocument(aBoundElement, aBoundDocument, documentURI,
+                              aBindingURI, aOriginPrincipal, aForceSyncLoad,
+                              getter_AddRefs(document));
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    if (document) {
+      nsBindingManager *xblDocBindingManager = document->BindingManager();
+      info = xblDocBindingManager->GetXBLDocumentInfo(documentURI);
+      if (!info) {
+        NS_ERROR("An XBL file is malformed.  Did you forget the XBL namespace on the bindings tag?");
+        return NS_ERROR_FAILURE;
+      }
+      xblDocBindingManager->RemoveXBLDocumentInfo(info); // Break the self-imposed cycle.
+
+      // If the doc is a chrome URI, then we put it into the XUL cache.
+#ifdef MOZ_XUL
+      if (useStartupCache) {
+        cache->PutXBLDocumentInfo(info);
+
+        // now write the bindings into the startup cache
+        info->WritePrototypeBindings();
+      }
+#endif
+    }
+  }
+
+  if (info && bindingManager) {
+    // Cache it in our binding manager's document table. This way,
+    // we can ensure that if the document has loaded this binding
+    // before, it can continue to use it even if the XUL prototype
+    // cache gets flushed. That way, if a flush does occur, we
+    // don't get into a weird state where we're using different
+    // XBLDocumentInfos for the same XBL document in a single
+    // document that has loaded some bindings.
+    bindingManager->PutXBLDocumentInfo(info);
+  }
+
+  info.forget(aResult);
+
+  return NS_OK;
+}
+
+nsresult
+nsXBLService::FetchBindingDocument(nsIContent* aBoundElement, nsIDocument* aBoundDocument,
+                                   nsIURI* aDocumentURI, nsIURI* aBindingURI,
+                                   nsIPrincipal* aOriginPrincipal, bool aForceSyncLoad,
+                                   nsIDocument** aResult)
+{
+  nsresult rv = NS_OK;
+  // Initialize our out pointer to nullptr
+  *aResult = nullptr;
+
+  // Now we have to synchronously load the binding file.
+  // Create an XML content sink and a parser.
+  nsCOMPtr<nsILoadGroup> loadGroup;
+  if (aBoundDocument)
+    loadGroup = aBoundDocument->GetDocumentLoadGroup();
+
+  // We really shouldn't have to force a sync load for anything here... could
+  // we get away with not doing that?  Not sure.
+  if (IsChromeOrResourceURI(aDocumentURI))
+    aForceSyncLoad = true;
+
+  // Create document and contentsink and set them up.
+  nsCOMPtr<nsIDocument> doc;
+  rv = NS_NewXMLDocument(getter_AddRefs(doc));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIXMLContentSink> xblSink;
+  rv = NS_NewXBLContentSink(getter_AddRefs(xblSink), doc, aDocumentURI, nullptr);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Open channel
+  // Note: There are some cases where aOriginPrincipal and aBoundDocument are purposely
+  // set to null (to bypass security checks) when calling LoadBindingDocumentInfo() which calls
+  // FetchBindingDocument().  LoadInfo will end up with no principal or node in those cases,
+  // so we use systemPrincipal.  This achieves the same result of bypassing security checks,
+  // but it gives the wrong information to potential future consumers of loadInfo.
+  nsCOMPtr<nsIChannel> channel;
+
+  if (aOriginPrincipal) {
+    // if there is an originPrincipal we should also have aBoundDocument
+    MOZ_ASSERT(aBoundDocument, "can not create a channel without aBoundDocument");
+
+    rv = NS_NewChannelWithTriggeringPrincipal(getter_AddRefs(channel),
+                                              aDocumentURI,
+                                              aBoundDocument,
+                                              aOriginPrincipal,
+                                              nsILoadInfo::SEC_REQUIRE_SAME_ORIGIN_DATA_INHERITS |
+                                              nsILoadInfo::SEC_ALLOW_CHROME,
+                                              nsIContentPolicy::TYPE_XBL,
+                                              loadGroup);
+  }
+  else {
+    rv = NS_NewChannel(getter_AddRefs(channel),
+                       aDocumentURI,
+                       nsContentUtils::GetSystemPrincipal(),
+                       nsILoadInfo::SEC_REQUIRE_SAME_ORIGIN_DATA_INHERITS,
+                       nsIContentPolicy::TYPE_XBL,
+                       loadGroup);
+  }
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (!aForceSyncLoad) {
+    // We can be asynchronous
+    nsXBLStreamListener* xblListener =
+      new nsXBLStreamListener(aBoundDocument, xblSink, doc);
+
+    // Add ourselves to the list of loading docs.
+    nsBindingManager *bindingManager;
+    if (aBoundDocument)
+      bindingManager = aBoundDocument->BindingManager();
+    else
+      bindingManager = nullptr;
+
+    if (bindingManager)
+      bindingManager->PutLoadingDocListener(aDocumentURI, xblListener);
+
+    // Add our request.
+    nsXBLBindingRequest* req = new nsXBLBindingRequest(aBindingURI,
+                                                       aBoundElement);
+    xblListener->AddRequest(req);
+
+    // Now kick off the async read.
+    rv = channel->AsyncOpen2(xblListener);
+    if (NS_FAILED(rv)) {
+      // Well, we won't be getting a load.  Make sure to clean up our stuff!
+      if (bindingManager) {
+        bindingManager->RemoveLoadingDocListener(aDocumentURI);
+      }
+    }
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsIStreamListener> listener;
+  rv = doc->StartDocumentLoad("loadAsInteractiveData",
+                              channel,
+                              loadGroup,
+                              nullptr,
+                              getter_AddRefs(listener),
+                              true,
+                              xblSink);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Now do a blocking synchronous parse of the file.
+  nsCOMPtr<nsIInputStream> in;
+  rv = channel->Open2(getter_AddRefs(in));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = nsSyncLoadService::PushSyncStreamToListener(in, listener, channel);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  doc.swap(*aResult);
+
+  return NS_OK;
+}