Add m-esr52 at 52.6.0

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 */