/* -*- 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 http://mozilla.org/MPL/2.0/. */

/*

 * rendering object that is the root of the frame tree, which contains

 * the document's scrollbars and contains fixed-positioned elements

 */

#include "mozilla/ViewportFrame.h"

#include "mozilla/ComputedStyleInlines.h"

#include "mozilla/RestyleManager.h"

#include "nsGkAtoms.h"

#include "nsIScrollableFrame.h"

#include "nsSubDocumentFrame.h"

#include "nsCanvasFrame.h"

#include "nsAbsoluteContainingBlock.h"

#include "GeckoProfiler.h"

#include "nsIMozBrowserFrame.h"

#include "nsPlaceholderFrame.h"

using namespace mozilla;

typedef nsAbsoluteContainingBlock::AbsPosReflowFlags AbsPosReflowFlags;

ViewportFrame*

NS_NewViewportFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle)

{

  return new (aPresShell) ViewportFrame(aStyle);

}

NS_IMPL_FRAMEARENA_HELPERS(ViewportFrame)

NS_QUERYFRAME_HEAD(ViewportFrame)

  NS_QUERYFRAME_ENTRY(ViewportFrame)

NS_QUERYFRAME_TAIL_INHERITING(nsContainerFrame)

void

ViewportFrame::Init(nsIContent*       aContent,

                    nsContainerFrame* aParent,

                    nsIFrame*         aPrevInFlow)

{

  nsContainerFrame::Init(aContent, aParent, aPrevInFlow);

  // No need to call CreateView() here - the frame ctor will call SetView()

  // with the ViewManager's root view, so we'll assign it in SetViewInternal().

  nsIFrame* parent = nsLayoutUtils::GetCrossDocParentFrame(this);

  if (parent) {

    nsFrameState state = parent->GetStateBits();

    AddStateBits(state & (NS_FRAME_IN_POPUP));

  }

}

void

ViewportFrame::BuildDisplayList(nsDisplayListBuilder*   aBuilder,

                                const nsDisplayListSet& aLists)

{

  AUTO_PROFILER_LABEL("ViewportFrame::BuildDisplayList", GRAPHICS);

  if (nsIFrame* kid = mFrames.FirstChild()) {

    // make the kid's BorderBackground our own. This ensures that the canvas

    // frame's background becomes our own background and therefore appears

    // below negative z-index elements.

    BuildDisplayListForChild(aBuilder, kid, aLists);

  }

  nsDisplayList topLayerList;

  BuildDisplayListForTopLayer(aBuilder, &topLayerList);

  if (!topLayerList.IsEmpty()) {

    // Wrap the whole top layer in a single item with maximum z-index,

    // and append it at the very end, so that it stays at the topmost.

    nsDisplayWrapList* wrapList =

      MakeDisplayItem<nsDisplayWrapList>(aBuilder, this, &topLayerList);

    wrapList->SetOverrideZIndex(

      std::numeric_limits<decltype(wrapList->ZIndex())>::max());

    aLists.PositionedDescendants()->AppendToTop(wrapList);

  }

}

#ifdef DEBUG

/**

 * Returns whether we are going to put an element in the top layer for

 * fullscreen. This function should matches the CSS rule in ua.css.

 */

static bool

ShouldInTopLayerForFullscreen(Element* aElement)

{

  if (!aElement->GetParent()) {

    return false;

  }

  nsCOMPtr<nsIMozBrowserFrame> browserFrame = do_QueryInterface(aElement);

  if (browserFrame && browserFrame->GetReallyIsBrowser()) {

    return false;

  }

  return true;

}

#endif // DEBUG

static void

BuildDisplayListForTopLayerFrame(nsDisplayListBuilder* aBuilder,

                                 nsIFrame* aFrame,

                                 nsDisplayList* aList)

{

  nsRect visible;

  nsRect dirty;

  DisplayListClipState::AutoClipMultiple clipState(aBuilder);

  nsDisplayListBuilder::AutoCurrentActiveScrolledRootSetter asrSetter(aBuilder);

  nsDisplayListBuilder::OutOfFlowDisplayData*

    savedOutOfFlowData = nsDisplayListBuilder::GetOutOfFlowData(aFrame);

  if (savedOutOfFlowData) {

    visible = savedOutOfFlowData->GetVisibleRectForFrame(aBuilder, aFrame, &dirty);

    // This function is called after we've finished building display items for

    // the root scroll frame. That means that the content clip from the root

    // scroll frame is no longer on aBuilder. However, we need to make sure

    // that the display items we build in this function have finite clipped

    // bounds with respect to the root ASR, so we restore the *combined clip*

    // that we saved earlier. The combined clip will include the clip from the

    // root scroll frame.

    clipState.SetClipChainForContainingBlockDescendants(

      savedOutOfFlowData->mCombinedClipChain);

    clipState.ClipContainingBlockDescendantsExtra(

      visible + aBuilder->ToReferenceFrame(aFrame), nullptr);

    asrSetter.SetCurrentActiveScrolledRoot(

      savedOutOfFlowData->mContainingBlockActiveScrolledRoot);

  }

  nsDisplayListBuilder::AutoBuildingDisplayList

    buildingForChild(aBuilder, aFrame, visible, dirty,

                     aBuilder->IsAtRootOfPseudoStackingContext());

  nsDisplayList list;

  aFrame->BuildDisplayListForStackingContext(aBuilder, &list);

  aList->AppendToTop(&list);

}

void

ViewportFrame::BuildDisplayListForTopLayer(nsDisplayListBuilder* aBuilder,

                                           nsDisplayList* aList)

{

  nsIDocument* doc = PresContext()->Document();

  nsTArray<Element*> fullscreenStack = doc->GetFullscreenStack();

  for (Element* elem : fullscreenStack) {

    if (nsIFrame* frame = elem->GetPrimaryFrame()) {

      // There are two cases where an element in fullscreen is not in

      // the top layer:

      // 1. When building display list for purpose other than painting,

      //    it is possible that there is inconsistency between the style

      //    info and the content tree.

      // 2. This is an element which we are not going to put in the top

      //    layer for fullscreen. See ShouldInTopLayerForFullscreen().

      // In both cases, we want to skip the frame here and paint it in

      // the normal path.

      if (frame->StyleDisplay()->mTopLayer == NS_STYLE_TOP_LAYER_NONE) {

        MOZ_ASSERT(!aBuilder->IsForPainting() ||

                   !ShouldInTopLayerForFullscreen(elem));

        continue;

      }

      MOZ_ASSERT(ShouldInTopLayerForFullscreen(elem));

      // Inner SVG, MathML elements, as well as children of some XUL

      // elements are not allowed to be out-of-flow. They should not

      // be handled as top layer element here.

      if (!(frame->GetStateBits() & NS_FRAME_OUT_OF_FLOW)) {

        MOZ_ASSERT(!elem->GetParent()->IsHTMLElement(), "HTML element "

                   "should always be out-of-flow if in the top layer");

        continue;

      }

      if (nsIFrame* backdropPh =

          frame->GetChildList(kBackdropList).FirstChild()) {

        MOZ_ASSERT(backdropPh->IsPlaceholderFrame());

        MOZ_ASSERT(!backdropPh->GetNextSibling(), "more than one ::backdrop?");

        MOZ_ASSERT(backdropPh->HasAnyStateBits(NS_FRAME_FIRST_REFLOW),

                   "did you intend to reflow ::backdrop placeholders?");

        nsIFrame* backdropFrame =

          static_cast<nsPlaceholderFrame*>(backdropPh)->GetOutOfFlowFrame();

        MOZ_ASSERT(backdropFrame);

        BuildDisplayListForTopLayerFrame(aBuilder, backdropFrame, aList);

      }

      BuildDisplayListForTopLayerFrame(aBuilder, frame, aList);

    }

  }

  nsIPresShell* shell = PresShell();

  if (nsCanvasFrame* canvasFrame = shell->GetCanvasFrame()) {

    if (Element* container = canvasFrame->GetCustomContentContainer()) {

      if (nsIFrame* frame = container->GetPrimaryFrame()) {

        MOZ_ASSERT(frame->StyleDisplay()->mTopLayer != NS_STYLE_TOP_LAYER_NONE,

                   "ua.css should ensure this");

        MOZ_ASSERT(frame->GetStateBits() & NS_FRAME_OUT_OF_FLOW);

        BuildDisplayListForTopLayerFrame(aBuilder, frame, aList);

      }

    }

  }

}

#ifdef DEBUG

void

ViewportFrame::AppendFrames(ChildListID     aListID,

                            nsFrameList&    aFrameList)

{

  NS_ASSERTION(aListID == kPrincipalList, "unexpected child list");

  NS_ASSERTION(GetChildList(aListID).IsEmpty(), "Shouldn't have any kids!");

  nsContainerFrame::AppendFrames(aListID, aFrameList);

}

void

ViewportFrame::InsertFrames(ChildListID     aListID,

                            nsIFrame*       aPrevFrame,

                            nsFrameList&    aFrameList)

{

  NS_ASSERTION(aListID == kPrincipalList, "unexpected child list");

  NS_ASSERTION(GetChildList(aListID).IsEmpty(), "Shouldn't have any kids!");

  nsContainerFrame::InsertFrames(aListID, aPrevFrame, aFrameList);

}

void

ViewportFrame::RemoveFrame(ChildListID     aListID,

                           nsIFrame*       aOldFrame)

{

  NS_ASSERTION(aListID == kPrincipalList, "unexpected child list");

  nsContainerFrame::RemoveFrame(aListID, aOldFrame);

}

#endif

/* virtual */ nscoord

ViewportFrame::GetMinISize(gfxContext *aRenderingContext)

{

  nscoord result;

  DISPLAY_MIN_INLINE_SIZE(this, result);

  if (mFrames.IsEmpty())

    result = 0;

  else

    result = mFrames.FirstChild()->GetMinISize(aRenderingContext);

  return result;

}

/* virtual */ nscoord

ViewportFrame::GetPrefISize(gfxContext *aRenderingContext)

{

  nscoord result;

  DISPLAY_PREF_INLINE_SIZE(this, result);

  if (mFrames.IsEmpty())

    result = 0;

  else

    result = mFrames.FirstChild()->GetPrefISize(aRenderingContext);

  return result;

}

nsPoint

ViewportFrame::AdjustReflowInputForScrollbars(ReflowInput* aReflowInput) const

{

  // Get our prinicpal child frame and see if we're scrollable

  nsIFrame* kidFrame = mFrames.FirstChild();

  nsIScrollableFrame* scrollingFrame = do_QueryFrame(kidFrame);

  if (scrollingFrame) {

    WritingMode wm = aReflowInput->GetWritingMode();

    LogicalMargin scrollbars(wm, scrollingFrame->GetActualScrollbarSizes());

    aReflowInput->SetComputedISize(aReflowInput->ComputedISize() -

                                   scrollbars.IStartEnd(wm));

    aReflowInput->AvailableISize() -= scrollbars.IStartEnd(wm);

    aReflowInput->SetComputedBSizeWithoutResettingResizeFlags(

      aReflowInput->ComputedBSize() - scrollbars.BStartEnd(wm));

    return nsPoint(scrollbars.Left(wm), scrollbars.Top(wm));

  }

  return nsPoint(0, 0);

}

nsRect

ViewportFrame::AdjustReflowInputAsContainingBlock(ReflowInput* aReflowInput) const

{

#ifdef DEBUG

  nsPoint offset =

#endif

    AdjustReflowInputForScrollbars(aReflowInput);

  NS_ASSERTION(GetAbsoluteContainingBlock()->GetChildList().IsEmpty() ||

               (offset.x == 0 && offset.y == 0),

               "We don't handle correct positioning of fixed frames with "

               "scrollbars in odd positions");

  // Layout fixed position elements to the visual viewport size if and only if

  // it has been set and it is larger than the computed size, otherwise use the

  // computed size.

  nsRect rect(0, 0, aReflowInput->ComputedWidth(), aReflowInput->ComputedHeight());

  nsIPresShell* ps = PresShell();

  if (ps->IsVisualViewportSizeSet() && rect.Size() < ps->GetVisualViewportSize()) {

    rect.SizeTo(ps->GetVisualViewportSize());

  }

  return rect;

}

void

ViewportFrame::Reflow(nsPresContext*           aPresContext,

                      ReflowOutput&     aDesiredSize,

                      const ReflowInput& aReflowInput,

                      nsReflowStatus&          aStatus)

{

  MarkInReflow();

  DO_GLOBAL_REFLOW_COUNT("ViewportFrame");

  DISPLAY_REFLOW(aPresContext, this, aReflowInput, aDesiredSize, aStatus);

  MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");

  NS_FRAME_TRACE_REFLOW_IN("ViewportFrame::Reflow");

  // Because |Reflow| sets ComputedBSize() on the child to our

  // ComputedBSize().

  AddStateBits(NS_FRAME_CONTAINS_RELATIVE_BSIZE);

  // Set our size up front, since some parts of reflow depend on it

  // being already set.  Note that the computed height may be

  // unconstrained; that's ok.  Consumers should watch out for that.

  SetSize(nsSize(aReflowInput.ComputedWidth(), aReflowInput.ComputedHeight()));

  // Reflow the main content first so that the placeholders of the

  // fixed-position frames will be in the right places on an initial

  // reflow.

  nscoord kidBSize = 0;

  WritingMode wm = aReflowInput.GetWritingMode();

  if (mFrames.NotEmpty()) {

    // Deal with a non-incremental reflow or an incremental reflow

    // targeted at our one-and-only principal child frame.

    if (aReflowInput.ShouldReflowAllKids() ||

        aReflowInput.IsBResize() ||

        NS_SUBTREE_DIRTY(mFrames.FirstChild())) {

      // Reflow our one-and-only principal child frame

      nsIFrame*           kidFrame = mFrames.FirstChild();

      ReflowOutput kidDesiredSize(aReflowInput);

      WritingMode         wm = kidFrame->GetWritingMode();

      LogicalSize         availableSpace = aReflowInput.AvailableSize(wm);

      ReflowInput   kidReflowInput(aPresContext, aReflowInput,

                                         kidFrame, availableSpace);

      // Reflow the frame

      kidReflowInput.SetComputedBSize(aReflowInput.ComputedBSize());

      ReflowChild(kidFrame, aPresContext, kidDesiredSize, kidReflowInput,

                  0, 0, 0, aStatus);

      kidBSize = kidDesiredSize.BSize(wm);

      FinishReflowChild(kidFrame, aPresContext, kidDesiredSize, nullptr, 0, 0, 0);

    } else {

      kidBSize = LogicalSize(wm, mFrames.FirstChild()->GetSize()).BSize(wm);

    }

  }

  NS_ASSERTION(aReflowInput.AvailableISize() != NS_UNCONSTRAINEDSIZE,

               "shouldn't happen anymore");

  // Return the max size as our desired size

  LogicalSize maxSize(wm, aReflowInput.AvailableISize(),

                      // Being flowed initially at an unconstrained block size

                      // means we should return our child's intrinsic size.

                      aReflowInput.ComputedBSize() != NS_UNCONSTRAINEDSIZE

                        ? aReflowInput.ComputedBSize()

                        : kidBSize);

  aDesiredSize.SetSize(wm, maxSize);

  aDesiredSize.SetOverflowAreasToDesiredBounds();

  if (HasAbsolutelyPositionedChildren()) {

    // Make a copy of the reflow state and change the computed width and height

    // to reflect the available space for the fixed items

    ReflowInput reflowInput(aReflowInput);

    if (reflowInput.AvailableBSize() == NS_UNCONSTRAINEDSIZE) {

      // We have an intrinsic-height document with abs-pos/fixed-pos children.

      // Set the available height and mComputedHeight to our chosen height.

      reflowInput.AvailableBSize() = maxSize.BSize(wm);

      // Not having border/padding simplifies things

      NS_ASSERTION(reflowInput.ComputedPhysicalBorderPadding() == nsMargin(0,0,0,0),

                   "Viewports can't have border/padding");

      reflowInput.SetComputedBSize(maxSize.BSize(wm));

    }

    nsRect rect = AdjustReflowInputAsContainingBlock(&reflowInput);

    nsOverflowAreas* overflowAreas = &aDesiredSize.mOverflowAreas;

    nsIScrollableFrame* rootScrollFrame =

                    aPresContext->PresShell()->GetRootScrollFrameAsScrollable();

    if (rootScrollFrame && !rootScrollFrame->IsIgnoringViewportClipping()) {

      overflowAreas = nullptr;

    }

    AbsPosReflowFlags flags =

      AbsPosReflowFlags::eCBWidthAndHeightChanged; // XXX could be optimized

    GetAbsoluteContainingBlock()->Reflow(this, aPresContext, reflowInput, aStatus,

                                         rect, flags, overflowAreas);

  }

  if (mFrames.NotEmpty()) {

    ConsiderChildOverflow(aDesiredSize.mOverflowAreas, mFrames.FirstChild());

  }

  // If we were dirty then do a repaint

  if (GetStateBits() & NS_FRAME_IS_DIRTY) {

    InvalidateFrame();

  }

  // Clipping is handled by the document container (e.g., nsSubDocumentFrame),

  // so we don't need to change our overflow areas.

  bool overflowChanged = FinishAndStoreOverflow(&aDesiredSize);

  if (overflowChanged) {

    // We may need to alert our container to get it to pick up the

    // overflow change.

    nsSubDocumentFrame* container = static_cast<nsSubDocumentFrame*>

      (nsLayoutUtils::GetCrossDocParentFrame(this));

    if (container && !container->ShouldClipSubdocument()) {

      container->PresShell()->

        FrameNeedsReflow(container, nsIPresShell::eResize, NS_FRAME_IS_DIRTY);

    }

  }

  NS_FRAME_TRACE_REFLOW_OUT("ViewportFrame::Reflow", aStatus);

  NS_FRAME_SET_TRUNCATION(aStatus, aReflowInput, aDesiredSize);

}

bool

ViewportFrame::ComputeCustomOverflow(nsOverflowAreas& aOverflowAreas)

{

  nsIScrollableFrame* rootScrollFrame =

    PresShell()->GetRootScrollFrameAsScrollable();

  if (rootScrollFrame && !rootScrollFrame->IsIgnoringViewportClipping()) {

    return false;

  }

  return nsContainerFrame::ComputeCustomOverflow(aOverflowAreas);

}

void

ViewportFrame::UpdateStyle(ServoRestyleState& aRestyleState)

{

 nsAtom* pseudo = Style()->GetPseudo();

  RefPtr<ComputedStyle> newStyle =

    aRestyleState.StyleSet().ResolveInheritingAnonymousBoxStyle(pseudo, nullptr);

  // We're special because we have a null GetContent(), so don't call things

  // like UpdateStyleOfOwnedChildFrame that try to append changes for the

  // content to the change list.  Nor do we computed a changehint, since we have

  // no way to apply it anyway.

  newStyle->ResolveSameStructsAs(Style());

  MOZ_ASSERT(!GetNextContinuation(), "Viewport has continuations?");

  SetComputedStyle(newStyle);

  UpdateStyleOfOwnedAnonBoxes(aRestyleState);

}

void

ViewportFrame::AppendDirectlyOwnedAnonBoxes(nsTArray<OwnedAnonBox>& aResult)

{

  if (mFrames.NotEmpty()) {

    aResult.AppendElement(mFrames.FirstChild());

  }

}

#ifdef DEBUG_FRAME_DUMP

nsresult

ViewportFrame::GetFrameName(nsAString& aResult) const

{

  return MakeFrameName(NS_LITERAL_STRING("Viewport"), aResult);

}

#endif