The Tor Browser: layout/base/RestyleTracker.cpp@b8a032363ba2 (annotated)

layout/base/RestyleTracker.cpp@b8a032363ba2 (annotated)

layout/base/RestyleTracker.cpp

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* -*- 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.
  */
 #include "RestyleTracker.h"
 #include "nsStyleChangeList.h"
 #include "RestyleManager.h"
 #include "GeckoProfiler.h"
 namespace mozilla {
 inline nsIDocument*
 RestyleTracker::Document() const {
   return mRestyleManager->PresContext()->Document();
 }
 #define RESTYLE_ARRAY_STACKSIZE 128
 struct LaterSiblingCollector {
   RestyleTracker* tracker;
   nsTArray< nsRefPtr<dom::Element> >* elements;
 };
 static PLDHashOperator
 CollectLaterSiblings(nsISupports* aElement,
                      RestyleTracker::RestyleData& aData,
                      void* aSiblingCollector)
 {
   dom::Element* element =
     static_cast<dom::Element*>(aElement);
   LaterSiblingCollector* collector =
     static_cast<LaterSiblingCollector*>(aSiblingCollector);
   // Only collect the entries that actually need restyling by us (and
   // haven't, for example, already been restyled).
   // It's important to not mess with the flags on entries not in our
   // document.
   if (element->GetCurrentDoc() == collector->tracker->Document() &&
       element->HasFlag(collector->tracker->RestyleBit()) &&
       (aData.mRestyleHint & eRestyle_LaterSiblings)) {
     collector->elements->AppendElement(element);
   }
   return PL_DHASH_NEXT;
 }
 struct RestyleCollector {
   RestyleTracker* tracker;
   RestyleTracker::RestyleEnumerateData** restyleArrayPtr;
 };
 static PLDHashOperator
 CollectRestyles(nsISupports* aElement,
                 RestyleTracker::RestyleData& aData,
                 void* aRestyleCollector)
 {
   dom::Element* element =
     static_cast<dom::Element*>(aElement);
   RestyleCollector* collector =
     static_cast<RestyleCollector*>(aRestyleCollector);
   // Only collect the entries that actually need restyling by us (and
   // haven't, for example, already been restyled).
   // It's important to not mess with the flags on entries not in our
   // document.
   if (element->GetCurrentDoc() != collector->tracker->Document() ||
       !element->HasFlag(collector->tracker->RestyleBit())) {
     return PL_DHASH_NEXT;
   }
   NS_ASSERTION(!element->HasFlag(collector->tracker->RootBit()) ||
                // Maybe we're just not reachable via the frame tree?
                (element->GetFlattenedTreeParent() &&
                 (!element->GetFlattenedTreeParent()->GetPrimaryFrame()||
                  element->GetFlattenedTreeParent()->GetPrimaryFrame()->IsLeaf())) ||
                // Or not reachable due to an async reinsert we have
                // pending?  If so, we'll have a reframe hint around.
                // That incidentally makes it safe that we still have
                // the bit, since any descendants that didn't get added
                // to the roots list because we had the bits will be
                // completely restyled in a moment.
                (aData.mChangeHint & nsChangeHint_ReconstructFrame),
                "Why did this not get handled while processing mRestyleRoots?");
   // Unset the restyle bits now, so if they get readded later as we
   // process we won't clobber that adding of the bit.
   element->UnsetFlags(collector->tracker->RestyleBit() |
                       collector->tracker->RootBit());
   RestyleTracker::RestyleEnumerateData** restyleArrayPtr =
     collector->restyleArrayPtr;
   RestyleTracker::RestyleEnumerateData* currentRestyle =
     *restyleArrayPtr;
   currentRestyle->mElement = element;
   currentRestyle->mRestyleHint = aData.mRestyleHint;
   currentRestyle->mChangeHint = aData.mChangeHint;
   // Increment to the next slot in the array
   *restyleArrayPtr = currentRestyle + 1;
   return PL_DHASH_NEXT;
 }
 inline void
 RestyleTracker::ProcessOneRestyle(Element* aElement,
                                   nsRestyleHint aRestyleHint,
                                   nsChangeHint aChangeHint)
 {
   NS_PRECONDITION((aRestyleHint & eRestyle_LaterSiblings) == 0,
                   "Someone should have handled this before calling us");
   NS_PRECONDITION(Document(), "Must have a document");
   NS_PRECONDITION(aElement->GetCurrentDoc() == Document(),
                   "Element has unexpected document");
   nsIFrame* primaryFrame = aElement->GetPrimaryFrame();
   if (aRestyleHint & (eRestyle_Self | eRestyle_Subtree)) {
     mRestyleManager->RestyleElement(aElement, primaryFrame, aChangeHint,
                                     *this,
                                     (aRestyleHint & eRestyle_Subtree) != 0);
   } else if (aChangeHint &&
              (primaryFrame ||
               (aChangeHint & nsChangeHint_ReconstructFrame))) {
     // Don't need to recompute style; just apply the hint
     nsStyleChangeList changeList;
     changeList.AppendChange(primaryFrame, aElement, aChangeHint);
     mRestyleManager->ProcessRestyledFrames(changeList);
   }
 }
 void
 RestyleTracker::DoProcessRestyles()
 {
   PROFILER_LABEL("CSS", "ProcessRestyles");
   mRestyleManager->BeginProcessingRestyles();
   // loop so that we process any restyle events generated by processing
   while (mPendingRestyles.Count()) {
     if (mHaveLaterSiblingRestyles) {
       // Convert them to individual restyles on all the later siblings
       nsAutoTArray<nsRefPtr<Element>, RESTYLE_ARRAY_STACKSIZE> laterSiblingArr;
       LaterSiblingCollector siblingCollector = { this, &laterSiblingArr };
       mPendingRestyles.Enumerate(CollectLaterSiblings, &siblingCollector);
       for (uint32_t i = 0; i < laterSiblingArr.Length(); ++i) {
         Element* element = laterSiblingArr[i];
         for (nsIContent* sibling = element->GetNextSibling();
              sibling;
              sibling = sibling->GetNextSibling()) {
           if (sibling->IsElement() &&
               AddPendingRestyle(sibling->AsElement(), eRestyle_Subtree,
                                 NS_STYLE_HINT_NONE)) {
               // Nothing else to do here; we'll handle the following
               // siblings when we get to |sibling| in laterSiblingArr.
             break;
           }
         }
       }
       // Now remove all those eRestyle_LaterSiblings bits
       for (uint32_t i = 0; i < laterSiblingArr.Length(); ++i) {
         Element* element = laterSiblingArr[i];
         NS_ASSERTION(element->HasFlag(RestyleBit()), "How did that happen?");
         RestyleData data;
 #ifdef DEBUG
         bool found =
 #endif
           mPendingRestyles.Get(element, &data);
         NS_ASSERTION(found, "Where did our entry go?");
         data.mRestyleHint =
           nsRestyleHint(data.mRestyleHint & ~eRestyle_LaterSiblings);
         mPendingRestyles.Put(element, data);
       }
       mHaveLaterSiblingRestyles = false;
     }
     uint32_t rootCount;
     while ((rootCount = mRestyleRoots.Length())) {
       // Make sure to pop the element off our restyle root array, so
       // that we can freely append to the array as we process this
       // element.
       nsRefPtr<Element> element;
       element.swap(mRestyleRoots[rootCount - 1]);
       mRestyleRoots.RemoveElementAt(rootCount - 1);
       // Do the document check before calling GetRestyleData, since we
       // don't want to do the sibling-processing GetRestyleData does if
       // the node is no longer relevant.
       if (element->GetCurrentDoc() != Document()) {
         // Content node has been removed from our document; nothing else
         // to do here
         continue;
       }
       RestyleData data;
       if (!GetRestyleData(element, &data)) {
         continue;
       }
       ProcessOneRestyle(element, data.mRestyleHint, data.mChangeHint);
     }
     if (mHaveLaterSiblingRestyles) {
       // Keep processing restyles for now
       continue;
     }
     // Now we only have entries with change hints left.  To be safe in
     // case of reentry from the handing of the change hint, use a
     // scratch array instead of calling out to ProcessOneRestyle while
     // enumerating the hashtable.  Use the stack if we can, otherwise
     // fall back on heap-allocation.
     nsAutoTArray<RestyleEnumerateData, RESTYLE_ARRAY_STACKSIZE> restyleArr;
     RestyleEnumerateData* restylesToProcess =
       restyleArr.AppendElements(mPendingRestyles.Count());
     if (restylesToProcess) {
       RestyleEnumerateData* lastRestyle = restylesToProcess;
       RestyleCollector collector = { this, &lastRestyle };
       mPendingRestyles.Enumerate(CollectRestyles, &collector);
       // Clear the hashtable now that we don't need it anymore
       mPendingRestyles.Clear();
       for (RestyleEnumerateData* currentRestyle = restylesToProcess;
            currentRestyle != lastRestyle;
            ++currentRestyle) {
         ProcessOneRestyle(currentRestyle->mElement,
                           currentRestyle->mRestyleHint,
                           currentRestyle->mChangeHint);
       }
     }
   }
   mRestyleManager->EndProcessingRestyles();
 }
 bool
 RestyleTracker::GetRestyleData(Element* aElement, RestyleData* aData)
 {
   NS_PRECONDITION(aElement->GetCurrentDoc() == Document(),
                   "Unexpected document; this will lead to incorrect behavior!");
   if (!aElement->HasFlag(RestyleBit())) {
     NS_ASSERTION(!aElement->HasFlag(RootBit()), "Bogus root bit?");
     return false;
   }
 #ifdef DEBUG
   bool gotData =
 #endif
   mPendingRestyles.Get(aElement, aData);
   NS_ASSERTION(gotData, "Must have data if restyle bit is set");
   if (aData->mRestyleHint & eRestyle_LaterSiblings) {
     // Someone readded the eRestyle_LaterSiblings hint for this
     // element.  Leave it around for now, but remove the other restyle
     // hints and the change hint for it.  Also unset its root bit,
     // since it's no longer a root with the new restyle data.
     RestyleData newData;
     newData.mChangeHint = nsChangeHint(0);
     newData.mRestyleHint = eRestyle_LaterSiblings;
     mPendingRestyles.Put(aElement, newData);
     aElement->UnsetFlags(RootBit());
     aData->mRestyleHint =
       nsRestyleHint(aData->mRestyleHint & ~eRestyle_LaterSiblings);
   } else {
     mPendingRestyles.Remove(aElement);
     aElement->UnsetFlags(mRestyleBits);
   }
   return true;
 }
 } // namespace mozilla

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layout/base/RestyleTracker.cpp@b8a032363ba2 (annotated)

layout/base/RestyleTracker.cpp