RestyleTracker.cpp
/* -*- 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
