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+/* -*- 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 */