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Diffstat (limited to 'layout/base/RestyleTracker.h')
| -rw-r--r-- | layout/base/RestyleTracker.h | 373 |
1 files changed, 373 insertions, 0 deletions
diff --git a/layout/base/RestyleTracker.h b/layout/base/RestyleTracker.h new file mode 100644 index 000000000..10a653cdb --- /dev/null +++ b/layout/base/RestyleTracker.h @@ -0,0 +1,373 @@ +/* -*- 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" + +#if defined(MOZ_ENABLE_PROFILER_SPS) +#include "ProfilerBacktrace.h" +#endif + +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 defined(MOZ_ENABLE_PROFILER_SPS) + UniquePtr<ProfilerBacktrace> mBacktrace; +#endif + }; + + /** + * 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); +#if defined(MOZ_ENABLE_PROFILER_SPS) + if (profiler_feature_active("restyle")) { + rd->mBacktrace.reset(profiler_get_backtrace()); + } +#endif + 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 */ |