void
ServoRestyleManager::PostRestyleEvent(Element* aElement,
nsRestyleHint aRestyleHint,
nsChangeHint aMinChangeHint)
{
if (MOZ_UNLIKELY(IsDisconnected()) ||
MOZ_UNLIKELY(PresContext()->PresShell()->IsDestroying())) {
return;
}
if (aRestyleHint == 0 && !aMinChangeHint && !HasPendingRestyles()) {
return; // Nothing to do.
}
// XXX This is a temporary hack to make style attribute change works.
// In the future, we should be able to use this hint directly.
if (aRestyleHint & eRestyle_StyleAttribute) {
aRestyleHint |= eRestyle_Subtree;
}
// Note that unlike in Servo, we don't mark elements as dirty until we process
// the restyle hints in ProcessPendingRestyles.
if (aRestyleHint || aMinChangeHint) {
ServoElementSnapshot* snapshot = SnapshotForElement(aElement);
snapshot->AddExplicitRestyleHint(aRestyleHint);
snapshot->AddExplicitChangeHint(aMinChangeHint);
}
PostRestyleEventInternal(false);
}
void
ServoRestyleManager::AttributeWillChange(Element* aElement,
int32_t aNameSpaceID,
nsIAtom* aAttribute, int32_t aModType,
const nsAttrValue* aNewValue)
{
ServoElementSnapshot* snapshot = SnapshotForElement(aElement);
snapshot->AddAttrs(aElement);
}
void
ServoRestyleManager::AttributeChanged(Element* aElement, int32_t aNameSpaceID,
nsIAtom* aAttribute, int32_t aModType,
const nsAttrValue* aOldValue)
{
#ifdef DEBUG
ServoElementSnapshot* snapshot = Servo_Element_GetSnapshot(aElement);
MOZ_ASSERT_IF(snapshot, snapshot->HasAttrs());
#endif
if (aAttribute == nsGkAtoms::style) {
PostRestyleEvent(aElement, eRestyle_StyleAttribute, nsChangeHint(0));
}
}
nsresult
ServoRestyleManager::ContentStateChanged(nsIContent* aContent,
EventStates aChangedBits)
{
if (!aContent->IsElement()) {
return NS_OK;
}
Element* aElement = aContent->AsElement();
nsChangeHint changeHint;
nsRestyleHint restyleHint;
// NOTE: restyleHint here is effectively always 0, since that's what
// ServoStyleSet::HasStateDependentStyle returns. Servo computes on
// ProcessPendingRestyles using the ElementSnapshot, but in theory could
// compute it sequentially easily.
//
// Determine what's the best way to do it, and how much work do we save
// processing the restyle hint early (i.e., computing the style hint here
// sequentially, potentially saving the snapshot), vs lazily (snapshot
// approach).
//
// If we take the sequential approach we need to specialize Servo's restyle
// hints system a bit more, and mesure whether we save something storing the
// restyle hint in the table and deferring the dirtiness setting until
// ProcessPendingRestyles (that's a requirement if we store snapshots though),
// vs processing the restyle hint in-place, dirtying the nodes on
// PostRestyleEvent.
//
// If we definitely take the snapshot approach, we should take rid of
// HasStateDependentStyle, etc (though right now they're no-ops).
ContentStateChangedInternal(aElement, aChangedBits, &changeHint,
&restyleHint);
EventStates previousState = aElement->StyleState() ^ aChangedBits;
ServoElementSnapshot* snapshot = Servo_Element_GetSnapshot(aElement);
if (snapshot) {
snapshot->AddState(previousState);
PostRestyleEvent(aElement, restyleHint, changeHint);
}
return NS_OK;
}
void
ServoRestyleManager::PostRestyleEvent(Element* aElement,
nsRestyleHint aRestyleHint,
nsChangeHint aMinChangeHint)
{
if (MOZ_UNLIKELY(IsDisconnected()) ||
MOZ_UNLIKELY(PresContext()->PresShell()->IsDestroying())) {
return;
}
if (aRestyleHint == 0 && !aMinChangeHint && !HasPendingRestyles()) {
return; // Nothing to do.
}
// Note that unlike in Servo, we don't mark elements as dirty until we process
// the restyle hints in ProcessPendingRestyles.
if (aRestyleHint || aMinChangeHint) {
ServoElementSnapshot* snapshot = SnapshotForElement(aElement);
snapshot->AddExplicitRestyleHint(aRestyleHint);
snapshot->AddExplicitChangeHint(aMinChangeHint);
}
PostRestyleEventInternal(false);
}
void
ServoRestyleManager::RecreateStyleContexts(nsIContent* aContent,
nsStyleContext* aParentContext,
ServoStyleSet* aStyleSet,
nsStyleChangeList& aChangeListToProcess)
{
MOZ_ASSERT(aContent->IsElement() || aContent->IsNodeOfType(nsINode::eTEXT));
nsIFrame* primaryFrame = aContent->GetPrimaryFrame();
if (!primaryFrame && !aContent->IsDirtyForServo()) {
// This happens when, for example, a display: none child of a
// HAS_DIRTY_DESCENDANTS content is reached as part of the traversal.
return;
}
// Work on text before.
if (!aContent->IsElement()) {
if (primaryFrame) {
RefPtr<nsStyleContext> oldStyleContext = primaryFrame->StyleContext();
RefPtr<nsStyleContext> newContext =
aStyleSet->ResolveStyleForText(aContent, aParentContext);
for (nsIFrame* f = primaryFrame; f;
f = GetNextContinuationWithSameStyle(f, oldStyleContext)) {
f->SetStyleContext(newContext);
}
}
aContent->UnsetIsDirtyForServo();
return;
}
Element* element = aContent->AsElement();
if (element->IsDirtyForServo()) {
RefPtr<ServoComputedValues> computedValues =
Servo_ComputedValues_Get(aContent).Consume();
MOZ_ASSERT(computedValues);
nsChangeHint changeHint = nsChangeHint(0);
// Add an explicit change hint if appropriate.
ServoElementSnapshot* snapshot;
if (mModifiedElements.Get(element, &snapshot)) {
changeHint |= snapshot->ExplicitChangeHint();
}
// Add the stored change hint if there's a frame. If there isn't a frame,
// generate a ReconstructFrame change hint if the new display value
// (which we can get from the ComputedValues stored on the node) is not
// none.
if (primaryFrame) {
changeHint |= primaryFrame->StyleContext()->ConsumeStoredChangeHint();
} else {
const nsStyleDisplay* currentDisplay =
Servo_GetStyleDisplay(computedValues);
if (currentDisplay->mDisplay != StyleDisplay::None) {
changeHint |= nsChangeHint_ReconstructFrame;
}
}
// Add the new change hint to the list of elements to process if
// we need to do any work.
if (changeHint) {
aChangeListToProcess.AppendChange(primaryFrame, element, changeHint);
}
// The frame reconstruction step (if needed) will ask for the descendants'
// style correctly. If not needed, we're done too.
if (!primaryFrame) {
aContent->UnsetIsDirtyForServo();
return;
}
// Hold the old style context alive, because it could become a dangling
// pointer during the replacement. In practice it's not a huge deal (on
// GetNextContinuationWithSameStyle the pointer is not dereferenced, only
// compared), but better not playing with dangling pointers if not needed.
RefPtr<nsStyleContext> oldStyleContext = primaryFrame->StyleContext();
MOZ_ASSERT(oldStyleContext);
RefPtr<nsStyleContext> newContext =
aStyleSet->GetContext(computedValues.forget(), aParentContext, nullptr,
CSSPseudoElementType::NotPseudo);
// XXX This could not always work as expected: there are kinds of content
// with the first split and the last sharing style, but others not. We
// should handle those properly.
for (nsIFrame* f = primaryFrame; f;
f = GetNextContinuationWithSameStyle(f, oldStyleContext)) {
f->SetStyleContext(newContext);
}
// Update pseudo-elements state if appropriate.
const static CSSPseudoElementType pseudosToRestyle[] = {
CSSPseudoElementType::before,
CSSPseudoElementType::after,
};
for (CSSPseudoElementType pseudoType : pseudosToRestyle) {
nsIAtom* pseudoTag = nsCSSPseudoElements::GetPseudoAtom(pseudoType);
if (nsIFrame* pseudoFrame = FrameForPseudoElement(element, pseudoTag)) {
// TODO: we could maybe make this more performant via calling into
// Servo just once to know which pseudo-elements we've got to restyle?
RefPtr<nsStyleContext> pseudoContext =
aStyleSet->ProbePseudoElementStyle(element, pseudoType, newContext);
// If pseudoContext is null here, it means the frame is going away, so
// our change hint computation should have already indicated we need
// to reframe.
MOZ_ASSERT_IF(!pseudoContext,
changeHint & nsChangeHint_ReconstructFrame);
if (pseudoContext) {
pseudoFrame->SetStyleContext(pseudoContext);
// We only care restyling text nodes, since other type of nodes
// (images), are still not supported. If that eventually changes, we
// may have to write more code here... Or not, I don't think too
// many inherited properties can affect those other frames.
StyleChildrenIterator it(pseudoFrame->GetContent());
for (nsIContent* n = it.GetNextChild(); n; n = it.GetNextChild()) {
if (n->IsNodeOfType(nsINode::eTEXT)) {
RefPtr<nsStyleContext> childContext =
aStyleSet->ResolveStyleForText(n, pseudoContext);
MOZ_ASSERT(n->GetPrimaryFrame(),
"How? This node is created at FC time!");
n->GetPrimaryFrame()->SetStyleContext(childContext);
}
}
}
}
}
aContent->UnsetIsDirtyForServo();
}
if (aContent->HasDirtyDescendantsForServo()) {
MOZ_ASSERT(primaryFrame,
"Frame construction should be scheduled, and it takes the "
"correct style for the children, so no need to be here.");
StyleChildrenIterator it(aContent);
for (nsIContent* n = it.GetNextChild(); n; n = it.GetNextChild()) {
if (n->IsElement() || n->IsNodeOfType(nsINode::eTEXT)) {
RecreateStyleContexts(n, primaryFrame->StyleContext(),
aStyleSet, aChangeListToProcess);
}
}
aContent->UnsetHasDirtyDescendantsForServo();
}
}
void
ServoRestyleManager::ProcessPendingRestyles()
{
MOZ_ASSERT(PresContext()->Document(), "No document? Pshaw!");
MOZ_ASSERT(!nsContentUtils::IsSafeToRunScript(), "Missing a script blocker!");
if (MOZ_UNLIKELY(!PresContext()->PresShell()->DidInitialize())) {
// PresShell::FlushPendingNotifications doesn't early-return in the case
// where the PreShell hasn't yet been initialized (and therefore we haven't
// yet done the initial style traversal of the DOM tree). We should arguably
// fix up the callers and assert against this case, but we just detect and
// handle it for now.
return;
}
if (!HasPendingRestyles()) {
return;
}
ServoStyleSet* styleSet = StyleSet();
nsIDocument* doc = PresContext()->Document();
Element* root = doc->GetRootElement();
if (root) {
for (auto iter = mModifiedElements.Iter(); !iter.Done(); iter.Next()) {
ServoElementSnapshot* snapshot = iter.UserData();
Element* element = iter.Key();
// TODO: avoid the ComputeRestyleHint call if we already have the highest
// explicit restyle hint?
nsRestyleHint hint = styleSet->ComputeRestyleHint(element, snapshot);
hint |= snapshot->ExplicitRestyleHint();
if (hint) {
NoteRestyleHint(element, hint);
}
}
if (root->IsDirtyForServo() || root->HasDirtyDescendantsForServo()) {
mInStyleRefresh = true;
styleSet->StyleDocument(/* aLeaveDirtyBits = */ true);
// First do any queued-up frame creation. (see bugs 827239 and 997506).
//
// XXXEmilio I'm calling this to avoid random behavior changes, since we
// delay frame construction after styling we should re-check once our
// model is more stable whether we can skip this call.
//
// Note this has to be *after* restyling, because otherwise frame
// construction will find unstyled nodes, and that's not funny.
PresContext()->FrameConstructor()->CreateNeededFrames();
nsStyleChangeList changeList;
RecreateStyleContexts(root, nullptr, styleSet, changeList);
ProcessRestyledFrames(changeList);
mInStyleRefresh = false;
}
}
MOZ_ASSERT(!doc->IsDirtyForServo());
doc->UnsetHasDirtyDescendantsForServo();
mModifiedElements.Clear();
IncrementRestyleGeneration();
}
