import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

dom/base/nsReferencedElement.cpp

@@ -0,0 +1,247 @@
+/* -*- 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 "nsReferencedElement.h"
+#include "nsContentUtils.h"
+#include "nsIURI.h"
+#include "nsBindingManager.h"
+#include "nsEscape.h"
+#include "nsXBLPrototypeBinding.h"
+#include "nsIDOMNode.h"
+#include "nsIDOMElement.h"
+#include "nsCycleCollectionParticipant.h"
+
+void
+nsReferencedElement::Reset(nsIContent* aFromContent, nsIURI* aURI,
+                           bool aWatch, bool aReferenceImage)
+{
+  MOZ_ASSERT(aFromContent, "Reset() expects non-null content pointer");
+
+  Unlink();
+
+  if (!aURI)
+    return;
+
+  nsAutoCString refPart;
+  aURI->GetRef(refPart);
+  // Unescape %-escapes in the reference. The result will be in the
+  // origin charset of the URL, hopefully...
+  NS_UnescapeURL(refPart);
+
+  nsAutoCString charset;
+  aURI->GetOriginCharset(charset);
+  nsAutoString ref;
+  nsresult rv = nsContentUtils::ConvertStringFromEncoding(charset,
+                                                          refPart,
+                                                          ref);
+  if (NS_FAILED(rv) || ref.IsEmpty()) {
+    return;
+  }
+
+  // Get the current document
+  nsIDocument *doc = aFromContent->OwnerDoc();
+  if (!doc)
+    return;
+
+  nsIContent* bindingParent = aFromContent->GetBindingParent();
+  if (bindingParent) {
+    nsXBLBinding* binding = bindingParent->GetXBLBinding();
+    if (!binding) {
+      // This happens, for example, if aFromContent is part of the content
+      // inserted by a call to nsIDocument::InsertAnonymousContent, which we
+      // also want to handle.  (It also happens for <use>'s anonymous
+      // content etc.)
+      Element* anonRoot =
+        doc->GetAnonRootIfInAnonymousContentContainer(aFromContent);
+      if (anonRoot) {
+        mElement = nsContentUtils::MatchElementId(anonRoot, ref);
+        // We don't have watching working yet for anonymous content, so bail out here.
+        return;
+      }
+    } else {
+      bool isEqualExceptRef;
+      rv = aURI->EqualsExceptRef(binding->PrototypeBinding()->DocURI(),
+                                 &isEqualExceptRef);
+      if (NS_SUCCEEDED(rv) && isEqualExceptRef) {
+        // XXX sXBL/XBL2 issue
+        // Our content is an anonymous XBL element from a binding inside the
+        // same document that the referenced URI points to. In order to avoid
+        // the risk of ID collisions we restrict ourselves to anonymous
+        // elements from this binding; specifically, URIs that are relative to
+        // the binding document should resolve to the copy of the target
+        // element that has been inserted into the bound document.
+        // If the URI points to a different document we don't need this
+        // restriction.
+        nsINodeList* anonymousChildren =
+          doc->BindingManager()->GetAnonymousNodesFor(bindingParent);
+
+        if (anonymousChildren) {
+          uint32_t length;
+          anonymousChildren->GetLength(&length);
+          for (uint32_t i = 0; i < length && !mElement; ++i) {
+            mElement =
+              nsContentUtils::MatchElementId(anonymousChildren->Item(i), ref);
+          }
+        }
+
+        // We don't have watching working yet for XBL, so bail out here.
+        return;
+      }
+    }
+  }
+
+  bool isEqualExceptRef;
+  rv = aURI->EqualsExceptRef(doc->GetDocumentURI(), &isEqualExceptRef);
+  if (NS_FAILED(rv) || !isEqualExceptRef) {
+    RefPtr<nsIDocument::ExternalResourceLoad> load;
+    doc = doc->RequestExternalResource(aURI, aFromContent,
+                                       getter_AddRefs(load));
+    if (!doc) {
+      if (!load || !aWatch) {
+        // Nothing will ever happen here
+        return;
+      }
+
+      DocumentLoadNotification* observer =
+        new DocumentLoadNotification(this, ref);
+      mPendingNotification = observer;
+      if (observer) {
+        load->AddObserver(observer);
+      }
+      // Keep going so we set up our watching stuff a bit
+    }
+  }
+
+  if (aWatch) {
+    nsCOMPtr<nsIAtom> atom = NS_Atomize(ref);
+    if (!atom)
+      return;
+    atom.swap(mWatchID);
+  }
+
+  mReferencingImage = aReferenceImage;
+
+  HaveNewDocument(doc, aWatch, ref);
+}
+
+void
+nsReferencedElement::ResetWithID(nsIContent* aFromContent, const nsString& aID,
+                                 bool aWatch)
+{
+  nsIDocument *doc = aFromContent->OwnerDoc();
+  if (!doc)
+    return;
+
+  // XXX Need to take care of XBL/XBL2
+
+  if (aWatch) {
+    nsCOMPtr<nsIAtom> atom = NS_Atomize(aID);
+    if (!atom)
+      return;
+    atom.swap(mWatchID);
+  }
+
+  mReferencingImage = false;
+
+  HaveNewDocument(doc, aWatch, aID);
+}
+
+void
+nsReferencedElement::HaveNewDocument(nsIDocument* aDocument, bool aWatch,
+                                     const nsString& aRef)
+{
+  if (aWatch) {
+    mWatchDocument = aDocument;
+    if (mWatchDocument) {
+      mElement = mWatchDocument->AddIDTargetObserver(mWatchID, Observe, this,
+                                                     mReferencingImage);
+    }
+    return;
+  }
+  
+  if (!aDocument) {
+    return;
+  }
+
+  Element *e = mReferencingImage ? aDocument->LookupImageElement(aRef) :
+                                   aDocument->GetElementById(aRef);
+  if (e) {
+    mElement = e;
+  }
+}
+
+void
+nsReferencedElement::Traverse(nsCycleCollectionTraversalCallback* aCB)
+{
+  NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(*aCB, "mWatchDocument");
+  aCB->NoteXPCOMChild(mWatchDocument);
+  NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(*aCB, "mContent");
+  aCB->NoteXPCOMChild(mElement);
+}
+
+void
+nsReferencedElement::Unlink()
+{
+  if (mWatchDocument && mWatchID) {
+    mWatchDocument->RemoveIDTargetObserver(mWatchID, Observe, this,
+                                           mReferencingImage);
+  }
+  if (mPendingNotification) {
+    mPendingNotification->Clear();
+    mPendingNotification = nullptr;
+  }
+  mWatchDocument = nullptr;
+  mWatchID = nullptr;
+  mElement = nullptr;
+  mReferencingImage = false;
+}
+
+bool
+nsReferencedElement::Observe(Element* aOldElement,
+                             Element* aNewElement, void* aData)
+{
+  nsReferencedElement* p = static_cast<nsReferencedElement*>(aData);
+  if (p->mPendingNotification) {
+    p->mPendingNotification->SetTo(aNewElement);
+  } else {
+    NS_ASSERTION(aOldElement == p->mElement, "Failed to track content!");
+    ChangeNotification* watcher =
+      new ChangeNotification(p, aOldElement, aNewElement);
+    p->mPendingNotification = watcher;
+    nsContentUtils::AddScriptRunner(watcher);
+  }
+  bool keepTracking = p->IsPersistent();
+  if (!keepTracking) {
+    p->mWatchDocument = nullptr;
+    p->mWatchID = nullptr;
+  }
+  return keepTracking;
+}
+
+NS_IMPL_ISUPPORTS_INHERITED0(nsReferencedElement::ChangeNotification,
+                             mozilla::Runnable)
+
+NS_IMPL_ISUPPORTS(nsReferencedElement::DocumentLoadNotification,
+                  nsIObserver)
+
+NS_IMETHODIMP
+nsReferencedElement::DocumentLoadNotification::Observe(nsISupports* aSubject,
+                                                       const char* aTopic,
+                                                       const char16_t* aData)
+{
+  NS_ASSERTION(PL_strcmp(aTopic, "external-resource-document-created") == 0,
+               "Unexpected topic");
+  if (mTarget) {
+    nsCOMPtr<nsIDocument> doc = do_QueryInterface(aSubject);
+    mTarget->mPendingNotification = nullptr;
+    NS_ASSERTION(!mTarget->mElement, "Why do we have content here?");
+    // If we got here, that means we had Reset() called with aWatch ==
+    // true.  So keep watching if IsPersistent().
+    mTarget->HaveNewDocument(doc, mTarget->IsPersistent(), mRef);
+    mTarget->ElementChanged(nullptr, mTarget->mElement);
+  }
+  return NS_OK;
+}