/* -*- 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/. */ #ifndef mozilla_RestyleManager_h #define mozilla_RestyleManager_h #include "mozilla/AutoRestore.h" #include "mozilla/Maybe.h" #include "mozilla/OverflowChangedTracker.h" #include "mozilla/ServoElementSnapshot.h" #include "mozilla/ServoElementSnapshotTable.h" #include "nsChangeHint.h" #include "nsPresContext.h" #include "nsPresContextInlines.h" // XXX Shouldn't be included by header though #include "nsStringFwd.h" #include "nsTHashSet.h" class nsAttrValue; class nsAtom; class nsIFrame; class nsStyleChangeList; class nsStyleChangeList; namespace mozilla { class ServoStyleSet; namespace dom { class Element; } /** * A stack class used to pass some common restyle state in a slightly more * comfortable way than a bunch of individual arguments, and that also checks * that the change hint used for optimization is correctly used in debug mode. */ class ServoRestyleState { public: ServoRestyleState( ServoStyleSet& aStyleSet, nsStyleChangeList& aChangeList, nsTArray& aPendingWrapperRestyles, nsTArray>& aPendingScrollAnchorSuppressions) : mStyleSet(aStyleSet), mChangeList(aChangeList), mPendingWrapperRestyles(aPendingWrapperRestyles), mPendingScrollAnchorSuppressions(aPendingScrollAnchorSuppressions), mPendingWrapperRestyleOffset(aPendingWrapperRestyles.Length()), mChangesHandled(nsChangeHint(0)) #ifdef DEBUG // If !mOwner, then we wouldn't have processed our wrapper restyles, // because we only process those when handling an element with a frame. // But that's OK, because if we started our traversal at an element with // no frame (e.g. it's display:contents), that means the wrapper frames // in our list actually inherit from one of its ancestors, not from it, // and hence not restyling them is OK. , mAssertWrapperRestyleLength(false) #endif // DEBUG { } // We shouldn't assume that changes handled from our parent are handled for // our children too if we're out of flow since they aren't necessarily // parented in DOM order, and thus a change handled by a DOM ancestor doesn't // necessarily mean that it's handled for an ancestor frame. enum class Type { InFlow, OutOfFlow, }; ServoRestyleState(const nsIFrame& aOwner, ServoRestyleState& aParentState, nsChangeHint aHintForThisFrame, Type aType, bool aAssertWrapperRestyleLength = true) : mStyleSet(aParentState.mStyleSet), mChangeList(aParentState.mChangeList), mPendingWrapperRestyles(aParentState.mPendingWrapperRestyles), mPendingScrollAnchorSuppressions( aParentState.mPendingScrollAnchorSuppressions), mPendingWrapperRestyleOffset( aParentState.mPendingWrapperRestyles.Length()), mChangesHandled(aType == Type::InFlow ? aParentState.mChangesHandled | aHintForThisFrame : aHintForThisFrame) #ifdef DEBUG , mOwner(&aOwner), mAssertWrapperRestyleLength(aAssertWrapperRestyleLength) #endif { if (aType == Type::InFlow) { AssertOwner(aParentState); } } ~ServoRestyleState() { MOZ_ASSERT( !mAssertWrapperRestyleLength || mPendingWrapperRestyles.Length() == mPendingWrapperRestyleOffset, "Someone forgot to call ProcessWrapperRestyles!"); } nsStyleChangeList& ChangeList() { return mChangeList; } ServoStyleSet& StyleSet() { return mStyleSet; } #ifdef DEBUG void AssertOwner(const ServoRestyleState& aParentState) const; nsChangeHint ChangesHandledFor(const nsIFrame*) const; #else void AssertOwner(const ServoRestyleState&) const {} nsChangeHint ChangesHandledFor(const nsIFrame*) const { return mChangesHandled; } #endif // Add a pending wrapper restyle. We don't have to do anything if the thing // being added is already last in the list, but otherwise we do want to add // it, in order for ProcessWrapperRestyles to work correctly. void AddPendingWrapperRestyle(nsIFrame* aWrapperFrame); // Process wrapper restyles for this restyle state. This should be done // before it comes off the stack. void ProcessWrapperRestyles(nsIFrame* aParentFrame); // Get the table-aware parent for the given child. This will walk through // outer table and cellcontent frames. static nsIFrame* TableAwareParentFor(const nsIFrame* aChild); // When the value of the position property changes such as we stop or start // being absolutely or fixed positioned, we need to suppress scroll anchoring // adjustments to avoid breaking websites. // // We do need to process all this once we're done with all our reframes, // to handle correctly the cases where we reconstruct an ancestor, like when // you reframe an ib-split (see bug 1559627 for example). // // This doesn't handle nested reframes. We'd need to rework quite some code to // do that, and so far it doesn't seem to be a problem in practice. void AddPendingScrollAnchorSuppression(dom::Element* aElement) { mPendingScrollAnchorSuppressions.AppendElement(aElement); } private: // Process a wrapper restyle at the given index, and restyles for any // wrappers nested in it. Returns the number of entries from // mPendingWrapperRestyles that we processed. The return value is always at // least 1. size_t ProcessMaybeNestedWrapperRestyle(nsIFrame* aParent, size_t aIndex); ServoStyleSet& mStyleSet; nsStyleChangeList& mChangeList; // A list of pending wrapper restyles. Anonymous box wrapper frames that need // restyling are added to this list when their non-anonymous kids are // restyled. This avoids us having to do linear searches along the frame tree // for these anonymous boxes. The problem then becomes that we can have // multiple kids all with the same anonymous parent, and we don't want to // restyle it more than once. We use mPendingWrapperRestyles to track which // anonymous wrapper boxes we've requested be restyled and which of them have // already been restyled. We use a single array propagated through // ServoRestyleStates by reference, because in a situation like this: // //
// // We have multiple wrappers to restyle (cell, row, table-row-group) and we // want to add them in to the list all at once but restyle them using // different ServoRestyleStates with different owners. When this situation // occurs, the relevant frames will be placed in the array with ancestors // before descendants. nsTArray& mPendingWrapperRestyles; nsTArray>& mPendingScrollAnchorSuppressions; // Since we're given a possibly-nonempty mPendingWrapperRestyles to start // with, we need to keep track of where the part of it we're responsible for // starts. size_t mPendingWrapperRestyleOffset; const nsChangeHint mChangesHandled; // We track the "owner" frame of this restyle state, that is, the frame that // generated the last change that is stored in mChangesHandled, in order to // verify that we only use mChangesHandled for actual descendants of that // frame (given DOM order isn't always frame order, and that there are a few // special cases for stuff like wrapper frames, ::backdrop, and so on). #ifdef DEBUG const nsIFrame* mOwner{nullptr}; #endif // Whether we should assert in our destructor that we've processed all of the // relevant wrapper restyles. #ifdef DEBUG const bool mAssertWrapperRestyleLength; #endif // DEBUG }; enum class ServoPostTraversalFlags : uint32_t; class RestyleManager { friend class ServoStyleSet; public: typedef ServoElementSnapshotTable SnapshotTable; typedef mozilla::dom::Element Element; // Get an integer that increments every time we process pending restyles. // The value is never 0. uint64_t GetRestyleGeneration() const { return mRestyleGeneration; } // Unlike GetRestyleGeneration, which means the actual restyling count, // GetUndisplayedRestyleGeneration represents any possible DOM changes that // can cause restyling. This is needed for getComputedStyle to work with // non-styled (e.g. display: none) elements. uint64_t GetUndisplayedRestyleGeneration() const { return mUndisplayedRestyleGeneration; } void Disconnect() { mPresContext = nullptr; } ~RestyleManager() { MOZ_ASSERT(!mAnimationsWithDestroyedFrame, "leaving dangling pointers from AnimationsWithDestroyedFrame"); MOZ_ASSERT(!mReentrantChanges); } #ifdef DEBUG static nsCString ChangeHintToString(nsChangeHint aHint); /** * DEBUG ONLY method to verify integrity of style tree versus frame tree */ void DebugVerifyStyleTree(nsIFrame* aFrame); #endif void FlushOverflowChangedTracker() { mOverflowChangedTracker.Flush(); } // Should be called when a frame is going to be destroyed and // WillDestroyFrameTree hasn't been called yet. void NotifyDestroyingFrame(nsIFrame* aFrame) { mOverflowChangedTracker.RemoveFrame(aFrame); // If ProcessRestyledFrames is tracking frames which have been // destroyed (to avoid re-visiting them), add this one to its set. if (mDestroyedFrames) { mDestroyedFrames->Insert(aFrame); } } // Note: It's the caller's responsibility to make sure to wrap a // ProcessRestyledFrames call in a view update batch and a script blocker. // This function does not call ProcessAttachedQueue() on the binding manager. // If the caller wants that to happen synchronously, it needs to handle that // itself. void ProcessRestyledFrames(nsStyleChangeList& aChangeList); bool IsInStyleRefresh() const { return mInStyleRefresh; } // AnimationsWithDestroyedFrame is used to stop animations and transitions // on elements that have no frame at the end of the restyling process. // It only lives during the restyling process. class MOZ_STACK_CLASS AnimationsWithDestroyedFrame final { public: // Construct a AnimationsWithDestroyedFrame object. The caller must // ensure that aRestyleManager lives at least as long as the // object. (This is generally easy since the caller is typically a // method of RestyleManager.) explicit AnimationsWithDestroyedFrame(RestyleManager* aRestyleManager); // This method takes the content node for the generated content for // animation/transition on ::before and ::after, rather than the // content node for the real element. void Put(nsIContent* aContent, ComputedStyle* aComputedStyle) { MOZ_ASSERT(aContent); PseudoStyleType pseudoType = aComputedStyle->GetPseudoType(); if (pseudoType == PseudoStyleType::NotPseudo) { mContents.AppendElement(aContent); } else if (pseudoType == PseudoStyleType::before) { MOZ_ASSERT(aContent->NodeInfo()->NameAtom() == nsGkAtoms::mozgeneratedcontentbefore); mBeforeContents.AppendElement(aContent->GetParent()); } else if (pseudoType == PseudoStyleType::after) { MOZ_ASSERT(aContent->NodeInfo()->NameAtom() == nsGkAtoms::mozgeneratedcontentafter); mAfterContents.AppendElement(aContent->GetParent()); } else if (pseudoType == PseudoStyleType::marker) { MOZ_ASSERT(aContent->NodeInfo()->NameAtom() == nsGkAtoms::mozgeneratedcontentmarker); mMarkerContents.AppendElement(aContent->GetParent()); } } void StopAnimationsForElementsWithoutFrames(); private: void StopAnimationsWithoutFrame(nsTArray>& aArray, PseudoStyleType aPseudoType); RestyleManager* mRestyleManager; AutoRestore mRestorePointer; // Below three arrays might include elements that have already had their // animations or transitions stopped. // // mBeforeContents, mAfterContents and mMarkerContents hold the real element // rather than the content node for the generated content (which might // change during a reframe) nsTArray> mContents; nsTArray> mBeforeContents; nsTArray> mAfterContents; nsTArray> mMarkerContents; }; /** * Return the current AnimationsWithDestroyedFrame struct, or null if we're * not currently in a restyling operation. */ AnimationsWithDestroyedFrame* GetAnimationsWithDestroyedFrame() { return mAnimationsWithDestroyedFrame; } void ContentInserted(nsIContent* aChild); void ContentAppended(nsIContent* aFirstNewContent); // This would be have the same logic as RestyleForInsertOrChange if we got the // notification before the removal. However, we get it after, so we need the // following sibling in addition to the old child. // // aFollowingSibling is the sibling that used to come after aOldChild before // the removal. void ContentRemoved(nsIContent* aOldChild, nsIContent* aFollowingSibling); // Restyling for a ContentInserted (notification after insertion) or // for some CharacterDataChanged. void RestyleForInsertOrChange(nsIContent* aChild); // Restyle for a CharacterDataChanged notification. In practice this can only // affect :empty / :-moz-only-whitespace / :-moz-first-node / :-moz-last-node. void CharacterDataChanged(nsIContent*, const CharacterDataChangeInfo&); void PostRestyleEvent(dom::Element*, RestyleHint, nsChangeHint aMinChangeHint); /** * Posts restyle hints for animations. * This is only called for the second traversal for CSS animations during * updating CSS animations in a SequentialTask. * This function does neither register a refresh observer nor flag that a * style flush is needed since this function is supposed to be called during * restyling process and this restyle event will be processed in the second * traversal of the same restyling process. */ void PostRestyleEventForAnimations(dom::Element*, PseudoStyleType, RestyleHint); void NextRestyleIsForCSSRuleChanges() { mRestyleForCSSRuleChanges = true; } void RebuildAllStyleData(nsChangeHint aExtraHint, RestyleHint); void ProcessPendingRestyles(); void ProcessAllPendingAttributeAndStateInvalidations(); void ElementStateChanged(Element*, dom::ElementState); void AttributeWillChange(Element* aElement, int32_t aNameSpaceID, nsAtom* aAttribute, int32_t aModType); void ClassAttributeWillBeChangedBySMIL(dom::Element* aElement); void AttributeChanged(dom::Element* aElement, int32_t aNameSpaceID, nsAtom* aAttribute, int32_t aModType, const nsAttrValue* aOldValue); // This is only used to reparent things when moving them in/out of the // ::first-line. void ReparentComputedStyleForFirstLine(nsIFrame*); /** * Performs a Servo animation-only traversal to compute style for all nodes * with the animation-only dirty bit in the document. * * This processes just the traversal for animation-only restyles and skips the * normal traversal for other restyles unrelated to animations. * This is used to bring throttled animations up-to-date such as when we need * to get correct position for transform animations that are throttled because * they are running on the compositor. * * This will traverse all of the document's style roots (that is, its document * element, and the roots of the document-level native anonymous content). */ void UpdateOnlyAnimationStyles(); // Get a counter that increments on every style change, that we use to // track whether off-main-thread animations are up-to-date. uint64_t GetAnimationGeneration() const { return mAnimationGeneration; } // Typically only style frames have animations associated with them so this // will likely return zero for anything that is not a style frame. static uint64_t GetAnimationGenerationForFrame(nsIFrame* aStyleFrame); // Update the animation generation count to mark that animation state // has changed. // // This is normally performed automatically by ProcessPendingRestyles // but it is also called when we have out-of-band changes to animations // such as changes made through the Web Animations API. void IncrementAnimationGeneration(); // Apply change hints for animations on the compositor. // // There are some cases where we forcibly apply change hints for animations // even if there is no change hint produced in order to synchronize with // animations running on the compositor. // // For example: // // a) Pausing animations via the Web Animations API // b) When the style before sending the animation to the compositor exactly // the same as the current style static void AddLayerChangesForAnimation( nsIFrame* aStyleFrame, nsIFrame* aPrimaryFrame, Element* aElement, nsChangeHint aHintForThisFrame, nsStyleChangeList& aChangeListToProcess); /** * Whether to clear all the style data (including the element itself), or just * the descendants' data. */ enum class IncludeRoot { Yes, No, }; /** * Clears the ServoElementData and HasDirtyDescendants from all elements * in the subtree rooted at aElement. */ static void ClearServoDataFromSubtree(Element*, IncludeRoot = IncludeRoot::Yes); /** * Clears HasDirtyDescendants and RestyleData from all elements in the * subtree rooted at aElement. */ static void ClearRestyleStateFromSubtree(Element* aElement); explicit RestyleManager(nsPresContext* aPresContext); protected: /** * Reparent the descendants of aFrame. This is used by ReparentComputedStyle * and shouldn't be called by anyone else. aProviderChild, if non-null, is a * child that was the style parent for aFrame and hence shouldn't be * reparented. */ void ReparentFrameDescendants(nsIFrame* aFrame, nsIFrame* aProviderChild, ServoStyleSet& aStyleSet); /** * Performs post-Servo-traversal processing on this element and its * descendants. * * Returns whether any style did actually change. There may be cases where we * didn't need to change any style after all, for example, when a content * attribute changes that happens not to have any effect on the style of that * element or any descendant or sibling. */ bool ProcessPostTraversal(Element* aElement, ServoRestyleState& aRestyleState, ServoPostTraversalFlags aFlags); struct TextPostTraversalState; bool ProcessPostTraversalForText(nsIContent* aTextNode, TextPostTraversalState& aState, ServoRestyleState& aRestyleState, ServoPostTraversalFlags aFlags); ServoStyleSet* StyleSet() const { return PresContext()->StyleSet(); } void RestyleForEmptyChange(Element* aContainer); void MaybeRestyleForEdgeChildChange(Element* aContainer, nsIContent* aChangedChild); bool IsDisconnected() const { return !mPresContext; } void IncrementRestyleGeneration() { if (++mRestyleGeneration == 0) { // Keep mRestyleGeneration from being 0, since that's what // nsPresContext::GetRestyleGeneration returns when it no // longer has a RestyleManager. ++mRestyleGeneration; } IncrementUndisplayedRestyleGeneration(); } void IncrementUndisplayedRestyleGeneration() { if (++mUndisplayedRestyleGeneration == 0) { // Ensure mUndisplayedRestyleGeneration > 0, for the same reason as // IncrementRestyleGeneration. ++mUndisplayedRestyleGeneration; } } nsPresContext* PresContext() const { MOZ_ASSERT(mPresContext); return mPresContext; } private: nsPresContext* mPresContext; // weak, can be null after Disconnect(). uint64_t mRestyleGeneration; uint64_t mUndisplayedRestyleGeneration; // Used to keep track of frames that have been destroyed during // ProcessRestyledFrames, so we don't try to touch them again even if // they're referenced again later in the changelist. mozilla::UniquePtr> mDestroyedFrames; protected: // True if we're in the middle of a nsRefreshDriver refresh bool mInStyleRefresh; // The total number of animation flushes by this frame constructor. // Used to keep the layer and animation manager in sync. uint64_t mAnimationGeneration; OverflowChangedTracker mOverflowChangedTracker; AnimationsWithDestroyedFrame* mAnimationsWithDestroyedFrame = nullptr; const SnapshotTable& Snapshots() const { return mSnapshots; } void ClearSnapshots(); ServoElementSnapshot& SnapshotFor(Element&); void TakeSnapshotForAttributeChange(Element&, int32_t aNameSpaceID, nsAtom* aAttribute); void DoProcessPendingRestyles(ServoTraversalFlags aFlags); // Function to do the actual (recursive) work of // ReparentComputedStyleForFirstLine, once we have asserted the invariants // that only hold on the initial call. void DoReparentComputedStyleForFirstLine(nsIFrame*, ServoStyleSet&); // We use a separate data structure from nsStyleChangeList because we need a // frame to create nsStyleChangeList entries, and the primary frame may not be // attached yet. struct ReentrantChange { nsCOMPtr mContent; nsChangeHint mHint; }; typedef AutoTArray ReentrantChangeList; // Only non-null while processing change hints. See the comment in // ProcessPendingRestyles. ReentrantChangeList* mReentrantChanges = nullptr; // We use this flag to track if the current restyle contains any non-animation // update, which triggers a normal restyle, and so there might be any new // transition created later. Therefore, if this flag is true, we need to // increase mAnimationGeneration before creating new transitions, so their // creation sequence will be correct. bool mHaveNonAnimationRestyles = false; // Set to true when posting restyle events triggered by CSS rule changes. // This flag is cleared once ProcessPendingRestyles has completed. // When we process a traversal all descendants elements of the document // triggered by CSS rule changes, we will need to update all elements with // CSS animations. We propagate TraversalRestyleBehavior::ForCSSRuleChanges // to traversal function if this flag is set. bool mRestyleForCSSRuleChanges = false; // A hashtable with the elements that have changed state or attributes, in // order to calculate restyle hints during the traversal. SnapshotTable mSnapshots; }; } // namespace mozilla #endif