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authorMatt A. Tobin <email@mattatobin.com>2020-04-16 16:37:28 -0400
committerMatt A. Tobin <email@mattatobin.com>2020-04-16 16:37:28 -0400
commit4375774c901bac4bd1ecaa35b40f55397044b7e9 (patch)
tree5c1a39a427b89390ee5ae54f75b04fa6536fb4a4 /layout/base
parentc66ed1275f1039fdf23a8f2c172d7c0b4691d1c2 (diff)
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Bug 1331322 - Allow tagging of pseudo-implementing native anonymous content with the pseudo type at creation time
* Stop using a node bit for HasExplicitBaseURI * Move MAY_HAVE_CLASS to mBoolFlags * Add a flag to indicate that a node is native anonymous content * Allow tagging of pseudo-implementing native anonymous content with the pseudo type at creation time, and eliminate explicit style contexts in nsIAnonymousContentCreator::ContentInfo Tag #1375
Diffstat (limited to 'layout/base')
-rw-r--r--layout/base/RestyleManager.cpp10
-rw-r--r--layout/base/nsCSSFrameConstructor.cpp148
-rw-r--r--layout/base/nsCSSFrameConstructor.h3
3 files changed, 132 insertions, 29 deletions
diff --git a/layout/base/RestyleManager.cpp b/layout/base/RestyleManager.cpp
index 124b5535e..c3eeb8c71 100644
--- a/layout/base/RestyleManager.cpp
+++ b/layout/base/RestyleManager.cpp
@@ -2341,6 +2341,16 @@ ElementRestyler::ComputeRestyleResultFromFrame(nsIFrame* aSelf,
return;
}
+ // Each NAC element inherits from the first non-NAC ancestor, so child
+ // NAC may inherit from our parent instead of us. That means we can't
+ // cull traversal if our style context didn't change.
+ if (aSelf->GetContent() && aSelf->GetContent()->IsNativeAnonymous()) {
+ LOG_RESTYLE_CONTINUE("native anonymous content");
+ aRestyleResult = RestyleResult::eContinue;
+ aCanStopWithStyleChange = false;
+ return;
+ }
+
// Style changes might have moved children between the two nsLetterFrames
// (the one matching ::first-letter and the one containing the rest of the
// content). Continue restyling to the children of the nsLetterFrame so
diff --git a/layout/base/nsCSSFrameConstructor.cpp b/layout/base/nsCSSFrameConstructor.cpp
index 5a1036232..a2dec55e1 100644
--- a/layout/base/nsCSSFrameConstructor.cpp
+++ b/layout/base/nsCSSFrameConstructor.cpp
@@ -1865,6 +1865,7 @@ nsCSSFrameConstructor::CreateGeneratedContentItem(nsFrameConstructorState& aStat
if (NS_FAILED(rv))
return;
container->SetIsNativeAnonymousRoot();
+ container->SetPseudoElementType(aPseudoElement);
// If the parent is in a shadow tree, make sure we don't
// bind with a document because shadow roots and its descendants
@@ -4161,6 +4162,13 @@ ConnectAnonymousTreeDescendants(nsIContent* aParent,
}
}
+void SetNativeAnonymousBitOnDescendants(nsIContent *aRoot)
+{
+ for (nsIContent* curr = aRoot; curr; curr = curr->GetNextNode(aRoot)) {
+ curr->SetFlags(NODE_IS_NATIVE_ANONYMOUS);
+ }
+}
+
nsresult
nsCSSFrameConstructor::GetAnonymousContent(nsIContent* aParent,
nsIFrame* aParentFrame,
@@ -4182,16 +4190,17 @@ nsCSSFrameConstructor::GetAnonymousContent(nsIContent* aParent,
nsIContent* content = aContent[i].mContent;
NS_ASSERTION(content, "null anonymous content?");
+ ConnectAnonymousTreeDescendants(content, aContent[i].mChildren);
+
// least-surprise CSS binding until we do the SVG specified
// cascading rules for <svg:use> - bug 265894
if (aParentFrame->GetType() == nsGkAtoms::svgUseFrame) {
content->SetFlags(NODE_IS_ANONYMOUS_ROOT);
} else {
content->SetIsNativeAnonymousRoot();
+ SetNativeAnonymousBitOnDescendants(content);
}
- ConnectAnonymousTreeDescendants(content, aContent[i].mChildren);
-
bool anonContentIsEditable = content->HasFlag(NODE_IS_EDITABLE);
// If the parent is in a shadow tree, make sure we don't
@@ -4216,11 +4225,9 @@ nsCSSFrameConstructor::GetAnonymousContent(nsIContent* aParent,
}
if (ServoStyleSet* styleSet = mPresShell->StyleSet()->GetAsServo()) {
- // Eagerly compute styles for the anonymous content tree, but only do so
- // if the content doesn't have an explicit style context (if it does, we
- // don't need the normal computed values).
+ // Eagerly compute styles for the anonymous content tree.
for (auto& info : aContent) {
- if (!info.mStyleContext) {
+ if (info.mContent->IsElement()) {
styleSet->StyleNewSubtree(info.mContent);
}
}
@@ -4999,22 +5006,35 @@ nsCSSFrameConstructor::ResolveStyleContext(const InsertionPoint& aInsertion,
already_AddRefed<nsStyleContext>
nsCSSFrameConstructor::ResolveStyleContext(nsStyleContext* aParentStyleContext,
nsIContent* aContent,
- nsFrameConstructorState* aState)
+ nsFrameConstructorState* aState,
+ Element* aOriginatingElementOrNull)
{
StyleSetHandle styleSet = mPresShell->StyleSet();
aContent->OwnerDoc()->FlushPendingLinkUpdates();
RefPtr<nsStyleContext> result;
if (aContent->IsElement()) {
- if (aState) {
- result = styleSet->ResolveStyleFor(aContent->AsElement(),
- aParentStyleContext,
- aState->mTreeMatchContext);
+ auto pseudoType = aContent->AsElement()->GetPseudoElementType();
+ if (pseudoType == CSSPseudoElementType::NotPseudo) {
+ MOZ_ASSERT(!aOriginatingElementOrNull);
+ if (aState) {
+ result = styleSet->ResolveStyleFor(aContent->AsElement(),
+ aParentStyleContext,
+ aState->mTreeMatchContext);
+ } else {
+ result = styleSet->ResolveStyleFor(aContent->AsElement(),
+ aParentStyleContext);
+ }
} else {
- result = styleSet->ResolveStyleFor(aContent->AsElement(),
- aParentStyleContext);
+ MOZ_ASSERT(aOriginatingElementOrNull);
+ MOZ_ASSERT(aContent->IsInNativeAnonymousSubtree());
+ result = styleSet->ResolvePseudoElementStyle(aOriginatingElementOrNull,
+ pseudoType,
+ aParentStyleContext,
+ aContent->AsElement());
}
} else {
+ MOZ_ASSERT(!aOriginatingElementOrNull);
NS_ASSERTION(aContent->IsNodeOfType(nsINode::eTEXT),
"shouldn't waste time creating style contexts for "
"comments and processing instructions");
@@ -10643,23 +10663,95 @@ nsCSSFrameConstructor::AddFCItemsForAnonymousContent(
RefPtr<nsStyleContext> styleContext;
TreeMatchContext::AutoParentDisplayBasedStyleFixupSkipper
parentDisplayBasedStyleFixupSkipper(aState.mTreeMatchContext);
- if (aAnonymousItems[i].mStyleContext) {
- // If we have an explicit style context, that means that the anonymous
- // content creator had its own plan for the style, and doesn't need the
- // computed style obtained by cascading this content as a normal node.
- // This happens when a native anonymous node is used to implement a
- // pseudo-element. Allowing Servo to traverse these nodes would be wasted
- // work, so assert that we didn't do that.
- MOZ_ASSERT_IF(content->IsStyledByServo(), !content->HasServoData());
- styleContext = aAnonymousItems[i].mStyleContext.forget();
+
+ // Make sure we eagerly performed the servo cascade when the anonymous
+ // nodes were created.
+ MOZ_ASSERT_IF(content->IsStyledByServo() && content->IsElement(),
+ content->AsElement()->HasServoData());
+
+ // Determine whether this NAC is pseudo-implementing.
+ nsIAtom* pseudo = nullptr;
+ if (content->IsElement()) {
+ auto pseudoType = content->AsElement()->GetPseudoElementType();
+ if (pseudoType != CSSPseudoElementType::NotPseudo) {
+ pseudo = nsCSSPseudoElements::GetPseudoAtom(pseudoType);
+ }
+ }
+
+ // Determine the appropriate parent style for this NAC, and if the NAC
+ // implements a pseudo-element, the appropriate originating element
+ // (that is to say, the element to the left of the ::pseudo-element in
+ // the selector). This is all rather tricky, and merits some discussion.
+ //
+ // First, it's important to note that author stylesheets generally do not
+ // apply to elements in native-anonymous subtrees. The exceptions to
+ // this are web-exposed pseudo-elements, where authors can style the
+ // pseudo-implementing NAC if the originating element is not itself in a NAC
+ // subtree.
+ //
+ // For this reason, it's very important that we avoid using a style parent
+ // that is inside a NAC subtree together with an originating element that
+ // is not inside a NAC subtree, since that would allow authors to
+ // explicitly inherit styles from internal elements, potentially making
+ // the NAC hierarchy observable. To ensure this, and generally simplify
+ // things, we always set the originating element to the style parent.
+ //
+ // As a consequence of the above, all web-exposed pseudo-elements (which,
+ // by definition, must have a content-accessible originating element) must
+ // also inherit style from that same content-accessible element. To avoid
+ // unintuitive behavior differences between NAC elements that do and don't
+ // correspond to web-exposed pseudo-elements, we follow this protocol for
+ // all NAC, pseudo-implementing or not.
+ //
+ // However, things get tricky with the <video> element, where we have a
+ // bunch of XBL-generated anonymous content descending from a native-
+ // anonymous XULElement. The XBL elements inherit style from their
+ // flattened tree parent, because that's how XBL works. But then we need
+ // to figure out what to do when one of those anonymous XBL elements
+ // (like an <input> element) generates its own (possibly pseudo-element-
+ // implementing) NAC.
+ //
+ // In this case, we inherit style from the XBL-generated NAC-creating
+ // element, rather than the <video> element. There are a number of good
+ // reasons for this. First, inheriting from the great-grandparent while
+ // the parent inherits from the grandparent would be bizarre at best.
+ // Second, exposing pseudo-elements from elements within our particular
+ // XBL implementation would allow content styles to (un)intentionally
+ // alter the video controls, which would be very bad. Third, our UA
+ // stylesheets have selectors like:
+ //
+ // input[type=range][orient=horizontal]::-moz-range-track
+ //
+ // and we need to make sure that the originating element is the <input>,
+ // not the <video>, because that's where the |orient| attribute lives.
+ //
+ // The upshot of all of this is that, to find the style parent (and
+ // originating element, if applicable), we walk up our parent chain to the
+ // first element that is not itself NAC (distinct from whether it happens
+ // to be in a NAC subtree).
+ //
+ // To implement all this, we need to pass the correct parent style context
+ // here because SetPrimaryFrame() may not have been called on the content
+ // yet and thus ResolveStyleContext can't find it otherwise.
+ //
+ // We don't need to worry about display:contents here, because such
+ // elements don't get a frame and thus can't generate NAC. But we do need
+ // to worry about anonymous boxes, which CorrectStyleParentFrame handles
+ // for us.
+ nsIFrame* inheritFrame = aFrame;
+ while (inheritFrame->GetContent()->IsNativeAnonymous()) {
+ inheritFrame = inheritFrame->GetParent();
+ }
+ if (inheritFrame->GetType() == nsGkAtoms::canvasFrame) {
+ // CorrectStyleParentFrame returns nullptr if the prospective parent is
+ // the canvas frame, so avoid calling it in that situation.
} else {
- // If we don't have an explicit style context, that means we need the
- // ordinary computed values. Make sure we eagerly cascaded them when the
- // anonymous nodes were created.
- MOZ_ASSERT_IF(content->IsStyledByServo() && content->IsElement(),
- content->HasServoData());
- styleContext = ResolveStyleContext(aFrame, content, &aState);
+ inheritFrame = nsFrame::CorrectStyleParentFrame(inheritFrame, pseudo);
}
+ Element* originating = pseudo ? inheritFrame->GetContent()->AsElement() : nullptr;
+
+ styleContext =
+ ResolveStyleContext(inheritFrame->StyleContext(), content, &aState, originating);
nsTArray<nsIAnonymousContentCreator::ContentInfo>* anonChildren = nullptr;
if (!aAnonymousItems[i].mChildren.IsEmpty()) {
diff --git a/layout/base/nsCSSFrameConstructor.h b/layout/base/nsCSSFrameConstructor.h
index 89e5594e4..db0d92566 100644
--- a/layout/base/nsCSSFrameConstructor.h
+++ b/layout/base/nsCSSFrameConstructor.h
@@ -364,7 +364,8 @@ private:
already_AddRefed<nsStyleContext>
ResolveStyleContext(nsStyleContext* aParentStyleContext,
nsIContent* aContent,
- nsFrameConstructorState* aState);
+ nsFrameConstructorState* aState,
+ Element* aOriginatingElementOrNull = nullptr);
// Add the frame construction items for the given aContent and aParentFrame
// to the list. This might add more than one item in some rare cases.