/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ /* 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/. */ /** * A class which manages pending restyles. This handles keeping track * of what nodes restyles need to happen on and so forth. */ #ifndef mozilla_RestyleTracker_h #define mozilla_RestyleTracker_h #include "mozilla/dom/Element.h" #include "mozilla/OverflowChangedTracker.h" #include "nsAutoPtr.h" #include "nsClassHashtable.h" #include "nsContainerFrame.h" #include "nsIContentInlines.h" #include "mozilla/SplayTree.h" #include "mozilla/RestyleLogging.h" #include "GeckoProfiler.h" #include "mozilla/Maybe.h" namespace mozilla { class RestyleManager; class ElementRestyler; class RestyleTracker { public: typedef mozilla::dom::Element Element; friend class ElementRestyler; // for AddPendingRestyleToTable explicit RestyleTracker(Element::FlagsType aRestyleBits) : mRestyleBits(aRestyleBits) , mHaveLaterSiblingRestyles(false) , mHaveSelectors(false) { NS_PRECONDITION((mRestyleBits & ~ELEMENT_ALL_RESTYLE_FLAGS) == 0, "Why do we have these bits set?"); NS_PRECONDITION((mRestyleBits & ELEMENT_PENDING_RESTYLE_FLAGS) != 0, "Must have a restyle flag"); NS_PRECONDITION((mRestyleBits & ELEMENT_PENDING_RESTYLE_FLAGS) != ELEMENT_PENDING_RESTYLE_FLAGS, "Shouldn't have both restyle flags set"); NS_PRECONDITION((mRestyleBits & ELEMENT_POTENTIAL_RESTYLE_ROOT_FLAGS) != 0, "Must have root flag"); NS_PRECONDITION((mRestyleBits & ELEMENT_POTENTIAL_RESTYLE_ROOT_FLAGS) != ELEMENT_POTENTIAL_RESTYLE_ROOT_FLAGS, "Shouldn't have both root flags"); } void Init(RestyleManager* aRestyleManager) { mRestyleManager = aRestyleManager; } uint32_t Count() const { return mPendingRestyles.Count(); } /** * Add a restyle for the given element to the tracker. Returns true * if the element already had eRestyle_LaterSiblings set on it. * * aRestyleRoot is the closest restyle root for aElement. If the caller * does not know what the closest restyle root is, Nothing should be * passed. A Some(nullptr) restyle root can be passed if there is no * ancestor element that is a restyle root. */ bool AddPendingRestyle(Element* aElement, nsRestyleHint aRestyleHint, nsChangeHint aMinChangeHint, const RestyleHintData* aRestyleHintData = nullptr, mozilla::Maybe<Element*> aRestyleRoot = mozilla::Nothing()); Element* FindClosestRestyleRoot(Element* aElement); /** * Process the restyles we've been tracking. */ void DoProcessRestyles(); // Return our ELEMENT_HAS_PENDING_(ANIMATION_)RESTYLE bit uint32_t RestyleBit() const { return mRestyleBits & ELEMENT_PENDING_RESTYLE_FLAGS; } // Return our ELEMENT_IS_POTENTIAL_(ANIMATION_)RESTYLE_ROOT bit Element::FlagsType RootBit() const { return mRestyleBits & ELEMENT_POTENTIAL_RESTYLE_ROOT_FLAGS; } // Return our ELEMENT_IS_CONDITIONAL_RESTYLE_ANCESTOR bit if present, // or 0 if it is not. Element::FlagsType ConditionalDescendantsBit() const { return mRestyleBits & ELEMENT_IS_CONDITIONAL_RESTYLE_ANCESTOR; } struct Hints { nsRestyleHint mRestyleHint; // What we want to restyle nsChangeHint mChangeHint; // The minimal change hint for "self" RestyleHintData mRestyleHintData; // Data associated with mRestyleHint }; struct RestyleData : Hints { RestyleData() { mRestyleHint = nsRestyleHint(0); mChangeHint = nsChangeHint(0); } RestyleData(nsRestyleHint aRestyleHint, nsChangeHint aChangeHint, const RestyleHintData* aRestyleHintData) { mRestyleHint = aRestyleHint; mChangeHint = aChangeHint; if (aRestyleHintData) { mRestyleHintData = *aRestyleHintData; } } // Descendant elements we must check that we ended up restyling, ordered // with the same invariant as mRestyleRoots. The elements here are those // that we called AddPendingRestyle for and found the element this is // the RestyleData for as its nearest restyle root. nsTArray<RefPtr<Element>> mDescendants; }; /** * If the given Element has a restyle pending for it, return the * relevant restyle data. This function will clear everything other * than a possible eRestyle_LaterSiblings hint for aElement out of * our hashtable. The returned aData will never have an * eRestyle_LaterSiblings hint in it. * * The return value indicates whether any restyle data was found for * the element. aData is set to nullptr iff false is returned. */ bool GetRestyleData(Element* aElement, nsAutoPtr<RestyleData>& aData); /** * Returns whether there is a RestyleData entry in mPendingRestyles * for the given element. */ bool HasRestyleData(Element* aElement) { return mPendingRestyles.Contains(aElement); } /** * For each element in aElements, appends it to mRestyleRoots if it * has its restyle bit set. This is used to ensure we restyle elements * that we did not add as restyle roots initially (due to there being * an ancestor with the restyle root bit set), but which we might * not have got around to restyling due to the restyle process * terminating early with RestyleResul::eStop (see ElementRestyler::Restyle). * * This function must be called with elements in order such that * appending them to mRestyleRoots maintains its ordering invariant that * ancestors appear after descendants. */ void AddRestyleRootsIfAwaitingRestyle( const nsTArray<RefPtr<Element>>& aElements); /** * Converts any eRestyle_SomeDescendants restyle hints in the pending restyle * table into eRestyle_Subtree hints and clears out the associated arrays of * nsCSSSelector pointers. This is called in response to a style sheet change * that might have cause an nsCSSSelector to be destroyed. */ void ClearSelectors(); /** * The document we're associated with. */ inline nsIDocument* Document() const; #ifdef RESTYLE_LOGGING // Defined in RestyleTrackerInlines.h. inline bool ShouldLogRestyle(); inline int32_t& LoggingDepth(); #endif private: bool AddPendingRestyleToTable(Element* aElement, nsRestyleHint aRestyleHint, nsChangeHint aMinChangeHint, const RestyleHintData* aRestyleHintData = nullptr); /** * Handle a single mPendingRestyles entry. aRestyleHint must not * include eRestyle_LaterSiblings; that needs to be dealt with * before calling this function. */ inline void ProcessOneRestyle(Element* aElement, nsRestyleHint aRestyleHint, nsChangeHint aChangeHint, const RestyleHintData& aRestyleHintData); typedef nsClassHashtable<nsISupportsHashKey, RestyleData> PendingRestyleTable; typedef AutoTArray< RefPtr<Element>, 32> RestyleRootArray; // Our restyle bits. These will be a subset of ELEMENT_ALL_RESTYLE_FLAGS, and // will include one flag from ELEMENT_PENDING_RESTYLE_FLAGS, one flag // from ELEMENT_POTENTIAL_RESTYLE_ROOT_FLAGS, and might also include // ELEMENT_IS_CONDITIONAL_RESTYLE_ANCESTOR. Element::FlagsType mRestyleBits; RestyleManager* mRestyleManager; // Owns us // A hashtable that maps elements to pointers to RestyleData structs. The // values only make sense if the element's current document is our // document and it has our RestyleBit() flag set. In particular, // said bit might not be set if the element had a restyle posted and // then was moved around in the DOM. PendingRestyleTable mPendingRestyles; // An array that keeps track of our possible restyle roots. This // maintains the invariant that if A and B are both restyle roots // and A is an ancestor of B then A will come after B in the array. // We maintain this invariant by checking whether an element has an // ancestor with the restyle root bit set before appending it to the // array. RestyleRootArray mRestyleRoots; // True if we have some entries with the eRestyle_LaterSiblings // flag. We need this to avoid enumerating the hashtable looking // for such entries when we can't possibly have any. bool mHaveLaterSiblingRestyles; // True if we have some entries with selectors in the restyle hint data. // We use this to skip iterating over mPendingRestyles in ClearSelectors. bool mHaveSelectors; }; inline bool RestyleTracker::AddPendingRestyleToTable(Element* aElement, nsRestyleHint aRestyleHint, nsChangeHint aMinChangeHint, const RestyleHintData* aRestyleHintData) { RestyleData* existingData; if (aRestyleHintData && !aRestyleHintData->mSelectorsForDescendants.IsEmpty()) { mHaveSelectors = true; } // Check the RestyleBit() flag before doing the hashtable Get, since // it's possible that the data in the hashtable isn't actually // relevant anymore (if the flag is not set). if (aElement->HasFlag(RestyleBit())) { mPendingRestyles.Get(aElement, &existingData); } else { aElement->SetFlags(RestyleBit()); existingData = nullptr; } if (aRestyleHint & eRestyle_SomeDescendants) { NS_ASSERTION(ConditionalDescendantsBit(), "why are we getting eRestyle_SomeDescendants in an " "animation-only restyle?"); aElement->SetFlags(ConditionalDescendantsBit()); } if (!existingData) { RestyleData* rd = new RestyleData(aRestyleHint, aMinChangeHint, aRestyleHintData); mPendingRestyles.Put(aElement, rd); return false; } bool hadRestyleLaterSiblings = (existingData->mRestyleHint & eRestyle_LaterSiblings) != 0; existingData->mRestyleHint = nsRestyleHint(existingData->mRestyleHint | aRestyleHint); existingData->mChangeHint |= aMinChangeHint; if (aRestyleHintData) { existingData->mRestyleHintData.mSelectorsForDescendants .AppendElements(aRestyleHintData->mSelectorsForDescendants); } return hadRestyleLaterSiblings; } inline mozilla::dom::Element* RestyleTracker::FindClosestRestyleRoot(Element* aElement) { Element* cur = aElement; while (!cur->HasFlag(RootBit())) { nsIContent* parent = cur->GetFlattenedTreeParent(); // Stop if we have no parent or the parent is not an element or // we're part of the viewport scrollbars (because those are not // frametree descendants of the primary frame of the root // element). // XXXbz maybe the primary frame of the root should be the root scrollframe? if (!parent || !parent->IsElement() || // If we've hit the root via a native anonymous kid and that // this native anonymous kid is not obviously a descendant // of the root's primary frame, assume we're under the root // scrollbars. Since those don't get reresolved when // reresolving the root, we need to make sure to add the // element to mRestyleRoots. (cur->IsInNativeAnonymousSubtree() && !parent->GetParent() && cur->GetPrimaryFrame() && cur->GetPrimaryFrame()->GetParent() != parent->GetPrimaryFrame())) { return nullptr; } cur = parent->AsElement(); } return cur; } inline bool RestyleTracker::AddPendingRestyle(Element* aElement, nsRestyleHint aRestyleHint, nsChangeHint aMinChangeHint, const RestyleHintData* aRestyleHintData, mozilla::Maybe<Element*> aRestyleRoot) { bool hadRestyleLaterSiblings = AddPendingRestyleToTable(aElement, aRestyleHint, aMinChangeHint, aRestyleHintData); // We can only treat this element as a restyle root if we would // actually restyle its descendants (so either call // ElementRestyler::Restyle on it or just reframe it). if ((aRestyleHint & ~eRestyle_LaterSiblings) || (aMinChangeHint & nsChangeHint_ReconstructFrame)) { Element* cur = aRestyleRoot ? *aRestyleRoot : FindClosestRestyleRoot(aElement); if (!cur) { mRestyleRoots.AppendElement(aElement); cur = aElement; } // At this point some ancestor of aElement (possibly aElement // itself) is in mRestyleRoots. Set the root bit on aElement, to // speed up searching for an existing root on its descendants. aElement->SetFlags(RootBit()); if (cur != aElement) { // We are already going to restyle cur, one of aElement's ancestors, // but we might not end up restyling all the way down to aElement. // Record it in the RestyleData so we can ensure it does get restyled // after we deal with cur. // // As with the mRestyleRoots array, mDescendants maintains the // invariant that if two elements appear in the array and one // is an ancestor of the other, that the ancestor appears after // the descendant. RestyleData* curData; mPendingRestyles.Get(cur, &curData); NS_ASSERTION(curData, "expected to find a RestyleData for cur"); // If cur has an eRestyle_ForceDescendants restyle hint, then we // know that we will get to all descendants. Don't bother // recording the descendant to restyle in that case. if (curData && !(curData->mRestyleHint & eRestyle_ForceDescendants)) { curData->mDescendants.AppendElement(aElement); } } } mHaveLaterSiblingRestyles = mHaveLaterSiblingRestyles || (aRestyleHint & eRestyle_LaterSiblings) != 0; return hadRestyleLaterSiblings; } } // namespace mozilla #endif /* mozilla_RestyleTracker_h */