gecko-dev/dom/grid/GridTracks.cpp

/* -*- 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/. */

#include "GridTracks.h"

#include "GridDimension.h"
#include "GridTrack.h"
#include "mozilla/dom/GridBinding.h"
#include "nsGridContainerFrame.h"

namespace mozilla::dom {

NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(GridTracks, mParent, mTracks)
NS_IMPL_CYCLE_COLLECTING_ADDREF(GridTracks)
NS_IMPL_CYCLE_COLLECTING_RELEASE(GridTracks)
NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(GridTracks)
  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
  NS_INTERFACE_MAP_ENTRY(nsISupports)
NS_INTERFACE_MAP_END

GridTracks::GridTracks(GridDimension* aParent) : mParent(aParent) {
  MOZ_ASSERT(aParent, "Should never be instantiated with a null GridDimension");
}

GridTracks::~GridTracks() = default;

JSObject* GridTracks::WrapObject(JSContext* aCx,
                                 JS::Handle<JSObject*> aGivenProto) {
  return GridTracks_Binding::Wrap(aCx, this, aGivenProto);
}

uint32_t GridTracks::Length() const { return mTracks.Length(); }

GridTrack* GridTracks::Item(uint32_t aIndex) {
  return mTracks.SafeElementAt(aIndex);
}

GridTrack* GridTracks::IndexedGetter(uint32_t aIndex, bool& aFound) {
  aFound = aIndex < mTracks.Length();
  if (!aFound) {
    return nullptr;
  }
  return mTracks[aIndex];
}

void GridTracks::SetTrackInfo(const ComputedGridTrackInfo* aTrackInfo) {
  // rebuild the tracks based on aTrackInfo
  mTracks.Clear();

  if (!aTrackInfo) {
    return;
  }

  nscoord lastTrackEdge = 0;
  uint32_t repeatIndex = 0;
  auto AppendRemovedAutoFits = [this, &aTrackInfo, &lastTrackEdge,
                                &repeatIndex]() {
    uint32_t numRepeatTracks = aTrackInfo->mRemovedRepeatTracks.Length();
    // Add in removed auto-fit tracks
    while (repeatIndex < numRepeatTracks &&
           aTrackInfo->mRemovedRepeatTracks[repeatIndex]) {
      RefPtr<GridTrack> track = new GridTrack(this);
      mTracks.AppendElement(track);
      track->SetTrackValues(
          nsPresContext::AppUnitsToDoubleCSSPixels(lastTrackEdge),
          nsPresContext::AppUnitsToDoubleCSSPixels(0),
          GridDeclaration::Explicit, GridTrackState::Removed);
      repeatIndex++;
    }
    repeatIndex++;
  };

  for (size_t i = aTrackInfo->mStartFragmentTrack;
       i < aTrackInfo->mEndFragmentTrack; i++) {
    if (i >= aTrackInfo->mRepeatFirstTrack) {
      // Append removed auto-fit tracks, if appropriate. The
      // AppendRemovedAutoFits function exits early once it has been called
      // aTrackInfo->mRemovedRepeatTracks.Length() times -- a check we don't
      // replicate here or at subsequent calling sites.
      AppendRemovedAutoFits();
    }

    RefPtr<GridTrack> track = new GridTrack(this);
    mTracks.AppendElement(track);
    track->SetTrackValues(
        nsPresContext::AppUnitsToDoubleCSSPixels(aTrackInfo->mPositions[i]),
        nsPresContext::AppUnitsToDoubleCSSPixels(aTrackInfo->mSizes[i]),
        (
            // Implicit if index is before the first explicit track, or after
            // the last explicit track.
            (i < aTrackInfo->mNumLeadingImplicitTracks) ||
                    (i >= aTrackInfo->mNumLeadingImplicitTracks +
                              aTrackInfo->mNumExplicitTracks)
                ? GridDeclaration::Implicit
                : GridDeclaration::Explicit),
        GridTrackState(aTrackInfo->mStates[i]));

    lastTrackEdge = aTrackInfo->mPositions[i] + aTrackInfo->mSizes[i];
  }

  // Append any trailing removed auto-fit tracks.
  AppendRemovedAutoFits();
}

}  // namespace mozilla::dom