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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 */
* rendering object for the point that anchors out-of-flow rendering
* objects such as floats and absolutely positioned elements
#include "nsPlaceholderFrame.h"
#include "gfxContext.h"
#include "gfxUtils.h"
#include "mozilla/dom/ElementInlines.h"
#include "mozilla/gfx/2D.h"
#include "mozilla/PresShell.h"
#include "mozilla/PresShellInlines.h"
#include "mozilla/ServoStyleSetInlines.h"
#include "nsCSSFrameConstructor.h"
#include "nsDisplayList.h"
#include "nsLayoutUtils.h"
#include "nsPresContext.h"
#include "nsPresContextInlines.h"
#include "nsIFrameInlines.h"
#include "nsIContentInlines.h"
using namespace mozilla;
using namespace mozilla::dom;
using namespace mozilla::gfx;
nsPlaceholderFrame* NS_NewPlaceholderFrame(PresShell* aPresShell,
ComputedStyle* aStyle,
nsFrameState aTypeBits) {
return new (aPresShell)
nsPlaceholderFrame(aStyle, aPresShell->GetPresContext(), aTypeBits);
#ifdef DEBUG
/* virtual */
void nsPlaceholderFrame::AddInlineMinISize(
gfxContext* aRenderingContext, nsIFrame::InlineMinISizeData* aData) {
// Override AddInlineMinWith so that *nothing* happens. In
// particular, we don't want to zero out |aData->mTrailingWhitespace|,
// since nsLineLayout skips placeholders when trimming trailing
// whitespace, and we don't want to set aData->mSkipWhitespace to
// false.
// ...but push floats onto the list
if (mOutOfFlowFrame->IsFloating()) {
nscoord floatWidth = nsLayoutUtils::IntrinsicForContainer(
aRenderingContext, mOutOfFlowFrame, IntrinsicISizeType::MinISize);
InlineIntrinsicISizeData::FloatInfo(mOutOfFlowFrame, floatWidth));
/* virtual */
void nsPlaceholderFrame::AddInlinePrefISize(
gfxContext* aRenderingContext, nsIFrame::InlinePrefISizeData* aData) {
// Override AddInlinePrefWith so that *nothing* happens. In
// particular, we don't want to zero out |aData->mTrailingWhitespace|,
// since nsLineLayout skips placeholders when trimming trailing
// whitespace, and we don't want to set aData->mSkipWhitespace to
// false.
// ...but push floats onto the list
if (mOutOfFlowFrame->IsFloating()) {
nscoord floatWidth = nsLayoutUtils::IntrinsicForContainer(
aRenderingContext, mOutOfFlowFrame, IntrinsicISizeType::PrefISize);
InlineIntrinsicISizeData::FloatInfo(mOutOfFlowFrame, floatWidth));
void nsPlaceholderFrame::Reflow(nsPresContext* aPresContext,
ReflowOutput& aDesiredSize,
const ReflowInput& aReflowInput,
nsReflowStatus& aStatus) {
// NOTE that the ReflowInput passed to this method is not fully initialized,
// on the grounds that reflowing a placeholder is a rather trivial operation.
// (See bug 1367711.)
#ifdef DEBUG
// We should be getting reflowed before our out-of-flow. If this is our first
// reflow, and our out-of-flow has already received its first reflow (before
// us), complain.
// Popups are an exception though, because their position doesn't depend on
// the placeholder, so they don't have this requirement (and this condition
// doesn't hold anyways because the default popupgroup goes before than the
// default tooltip, for example).
if (HasAnyStateBits(NS_FRAME_FIRST_REFLOW) &&
!mOutOfFlowFrame->IsMenuPopupFrame() &&
!mOutOfFlowFrame->HasAnyStateBits(NS_FRAME_FIRST_REFLOW)) {
// Unfortunately, this can currently happen when the placeholder is in a
// later continuation or later IB-split sibling than its out-of-flow (as
// is the case in some of our existing unit tests). So for now, in that
// case, we'll warn instead of asserting.
bool isInContinuationOrIBSplit = false;
nsIFrame* ancestor = this;
while ((ancestor = ancestor->GetParent())) {
if (nsLayoutUtils::GetPrevContinuationOrIBSplitSibling(ancestor)) {
isInContinuationOrIBSplit = true;
if (isInContinuationOrIBSplit) {
NS_WARNING("Out-of-flow frame got reflowed before its placeholder");
} else {
NS_ERROR("Out-of-flow frame got reflowed before its placeholder");
MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");
static FrameChildListID ChildListIDForOutOfFlow(nsFrameState aPlaceholderState,
const nsIFrame* aChild) {
if (aPlaceholderState & PLACEHOLDER_FOR_FLOAT) {
return FrameChildListID::Float;
if (aPlaceholderState & PLACEHOLDER_FOR_FIXEDPOS) {
return nsLayoutUtils::MayBeReallyFixedPos(aChild)
? FrameChildListID::Fixed
: FrameChildListID::Absolute;
if (aPlaceholderState & PLACEHOLDER_FOR_ABSPOS) {
return FrameChildListID::Absolute;
MOZ_DIAGNOSTIC_ASSERT(false, "unknown list");
return FrameChildListID::Float;
void nsPlaceholderFrame::Destroy(DestroyContext& aContext) {
if (nsIFrame* oof = mOutOfFlowFrame) {
mOutOfFlowFrame = nullptr;
// Destroy the out of flow now.
ChildListID listId = ChildListIDForOutOfFlow(GetStateBits(), oof);
nsFrameManager* fm = PresContext()->FrameConstructor();
fm->RemoveFrame(aContext, listId, oof);
/* virtual */
bool nsPlaceholderFrame::CanContinueTextRun() const {
if (!mOutOfFlowFrame) {
return false;
// first-letter frames can continue text runs, and placeholders for floated
// first-letter frames can too
return mOutOfFlowFrame->CanContinueTextRun();
ComputedStyle* nsPlaceholderFrame::GetParentComputedStyleForOutOfFlow(
nsIFrame** aProviderFrame) const {
MOZ_ASSERT(GetParent(), "How can we not have a parent here?");
Element* parentElement =
mContent ? mContent->GetFlattenedTreeParentElement() : nullptr;
// See the similar code in nsIFrame::DoGetParentComputedStyle.
if (parentElement && MOZ_LIKELY(parentElement->HasServoData()) &&
Servo_Element_IsDisplayContents(parentElement)) {
RefPtr<ComputedStyle> style =
*aProviderFrame = nullptr;
// See the comment in GetParentComputedStyle to see why returning this as a
// weak ref is fine.
return style;
return GetLayoutParentStyleForOutOfFlow(aProviderFrame);
ComputedStyle* nsPlaceholderFrame::GetLayoutParentStyleForOutOfFlow(
nsIFrame** aProviderFrame) const {
// Lie about our pseudo so we can step out of all anon boxes and
// pseudo-elements. The other option would be to reimplement the
// {ib} split gunk here.
// See the hack in CorrectStyleParentFrame for why we pass `MAX`.
*aProviderFrame = CorrectStyleParentFrame(GetParent(), PseudoStyleType::MAX);
return *aProviderFrame ? (*aProviderFrame)->Style() : nullptr;
#if defined(DEBUG) || (defined(MOZ_REFLOW_PERF_DSP) && defined(MOZ_REFLOW_PERF))
void nsPlaceholderFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
const nsDisplayListSet& aLists) {
nsresult nsPlaceholderFrame::GetFrameName(nsAString& aResult) const {
return MakeFrameName(u"Placeholder"_ns, aResult);
void nsPlaceholderFrame::List(FILE* out, const char* aPrefix,
ListFlags aFlags) const {
nsCString str;
ListGeneric(str, aPrefix, aFlags);
if (mOutOfFlowFrame) {
str += " outOfFlowFrame=";
str += mOutOfFlowFrame->ListTag();
fprintf_stderr(out, "%s\n", str.get());