gecko-dev/dom/base/IDTracker.cpp

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8.1 KiB
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/* -*- 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 "IDTracker.h"
#include "mozilla/Encoding.h"
#include "nsContentUtils.h"
#include "nsIURI.h"
#include "nsBindingManager.h"
#include "nsEscape.h"
#include "nsXBLPrototypeBinding.h"
#include "nsCycleCollectionParticipant.h"
namespace mozilla {
namespace dom {
static DocumentOrShadowRoot* DocOrShadowFromContent(nsIContent& aContent) {
ShadowRoot* shadow = aContent.GetContainingShadow();
// We never look in <svg:use> shadow trees, for backwards compat.
while (shadow && shadow->Host()->IsSVGElement(nsGkAtoms::use)) {
shadow = shadow->Host()->GetContainingShadow();
}
if (shadow) {
return shadow;
}
return aContent.OwnerDoc();
}
void IDTracker::ResetToURIFragmentID(nsIContent* aFromContent, nsIURI* aURI,
nsIURI* aReferrer,
uint32_t aReferrerPolicy, bool aWatch,
bool aReferenceImage) {
MOZ_ASSERT(aFromContent,
"ResetToURIFragmentID() 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
// document charset, hopefully...
NS_UnescapeURL(refPart);
// Get the thing to observe changes to.
Document* doc = aFromContent->OwnerDoc();
DocumentOrShadowRoot* docOrShadow = DocOrShadowFromContent(*aFromContent);
auto encoding = doc->GetDocumentCharacterSet();
nsAutoString ref;
nsresult rv = encoding->DecodeWithoutBOMHandling(refPart, ref);
if (NS_FAILED(rv) || ref.IsEmpty()) {
return;
}
rv = NS_OK;
nsIContent* bindingParent = aFromContent->GetBindingParent();
if (bindingParent && !aFromContent->IsInShadowTree()) {
nsXBLBinding* binding = bindingParent->GetXBLBinding();
if (!binding) {
// This happens, for example, if aFromContent is part of the content
// inserted by a call to Document::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->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<Document::ExternalResourceLoad> load;
doc = doc->RequestExternalResource(aURI, aReferrer, aReferrerPolicy,
aFromContent, getter_AddRefs(load));
docOrShadow = doc;
if (!doc) {
if (!load || !aWatch) {
// Nothing will ever happen here
return;
}
DocumentLoadNotification* observer =
new DocumentLoadNotification(this, ref);
mPendingNotification = observer;
load->AddObserver(observer);
// Keep going so we set up our watching stuff a bit
}
}
if (aWatch) {
mWatchID = NS_Atomize(ref);
}
mReferencingImage = aReferenceImage;
HaveNewDocumentOrShadowRoot(docOrShadow, aWatch, ref);
}
void IDTracker::ResetWithID(Element& aFrom, nsAtom* aID, bool aWatch) {
MOZ_ASSERT(aID);
if (aWatch) {
mWatchID = aID;
}
mReferencingImage = false;
DocumentOrShadowRoot* docOrShadow = DocOrShadowFromContent(aFrom);
HaveNewDocumentOrShadowRoot(docOrShadow, aWatch, nsDependentAtomString(aID));
}
void IDTracker::HaveNewDocumentOrShadowRoot(DocumentOrShadowRoot* aDocOrShadow,
bool aWatch, const nsString& aRef) {
if (aWatch) {
mWatchDocumentOrShadowRoot = nullptr;
if (aDocOrShadow) {
mWatchDocumentOrShadowRoot = &aDocOrShadow->AsNode();
mElement = aDocOrShadow->AddIDTargetObserver(mWatchID, Observe, this,
mReferencingImage);
}
return;
}
if (!aDocOrShadow) {
return;
}
Element* e = mReferencingImage ? aDocOrShadow->LookupImageElement(aRef)
: aDocOrShadow->GetElementById(aRef);
if (e) {
mElement = e;
}
}
void IDTracker::Traverse(nsCycleCollectionTraversalCallback* aCB) {
NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(*aCB, "mWatchDocumentOrShadowRoot");
aCB->NoteXPCOMChild(mWatchDocumentOrShadowRoot);
NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(*aCB, "mElement");
aCB->NoteXPCOMChild(mElement);
}
void IDTracker::Unlink() {
if (mWatchID) {
if (DocumentOrShadowRoot* docOrShadow = GetWatchDocOrShadowRoot()) {
docOrShadow->RemoveIDTargetObserver(mWatchID, Observe, this,
mReferencingImage);
}
}
if (mPendingNotification) {
mPendingNotification->Clear();
mPendingNotification = nullptr;
}
mWatchDocumentOrShadowRoot = nullptr;
mWatchID = nullptr;
mElement = nullptr;
mReferencingImage = false;
}
bool IDTracker::Observe(Element* aOldElement, Element* aNewElement,
void* aData) {
IDTracker* p = static_cast<IDTracker*>(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->mWatchDocumentOrShadowRoot = nullptr;
p->mWatchID = nullptr;
}
return keepTracking;
}
NS_IMPL_ISUPPORTS_INHERITED0(IDTracker::ChangeNotification, mozilla::Runnable)
NS_IMPL_ISUPPORTS(IDTracker::DocumentLoadNotification, nsIObserver)
NS_IMETHODIMP
IDTracker::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<Document> 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->HaveNewDocumentOrShadowRoot(doc, mTarget->IsPersistent(), mRef);
mTarget->ElementChanged(nullptr, mTarget->mElement);
}
return NS_OK;
}
} // namespace dom
} // namespace mozilla