/* 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/. */

/*
 * Inlined methods for ComputedStyle. Will just redirect to
 * GeckoComputedStyle methods when compiled without stylo, but will do
 * virtual dispatch (by checking which kind of container it is)
 * in stylo mode.
 */

#ifndef ComputedStyleInlines_h
#define ComputedStyleInlines_h

#include "MainThreadUtils.h"
#include "mozilla/Assertions.h"
#include "mozilla/CachedInheritingStyles.h"
#include "mozilla/ComputedStyle.h"
#include "mozilla/PseudoStyleType.h"
#include "nsStyleStructInlines.h"
#include "nsStyleStructList.h"

namespace mozilla {

namespace detail {

template <typename T, typename Enable = void>
struct HasTriggerImageLoads : public std::false_type {};

template <typename T>
struct HasTriggerImageLoads<T, decltype(std::declval<T&>().TriggerImageLoads(
                                   std::declval<dom::Document&>(), nullptr))>
    : public std::true_type {};

template <typename T, const T* (ComputedStyle::*Method)() const>
void TriggerImageLoads(dom::Document& aDocument, const ComputedStyle* aOldStyle,
                       ComputedStyle* aStyle) {
  if constexpr (HasTriggerImageLoads<T>::value) {
    auto* old = aOldStyle ? (aOldStyle->*Method)() : nullptr;
    auto* current = const_cast<T*>((aStyle->*Method)());
    current->TriggerImageLoads(aDocument, old);
  } else {
    (void)aOldStyle;
    (void)aStyle;
  }
}

}  // namespace detail

void ComputedStyle::StartImageLoads(dom::Document& aDocument,
                                    const ComputedStyle* aOldStyle) {
  MOZ_ASSERT(NS_IsMainThread());

#define TRIGGER_IMAGE_LOADS(name_)                                         \
  detail::TriggerImageLoads<nsStyle##name_, &ComputedStyle::Style##name_>( \
      aDocument, aOldStyle, this);
  FOR_EACH_STYLE_STRUCT(TRIGGER_IMAGE_LOADS, TRIGGER_IMAGE_LOADS)
#undef TRIGGER_IMAGE_LOADS
}

StylePointerEvents ComputedStyle::PointerEvents() const {
  if (IsRootElementStyle()) {
    // The root frame is not allowed to have pointer-events: none, or else no
    // frames could be hit test against and scrolling the viewport would not
    // work.
    return StylePointerEvents::Auto;
  }
  const auto& ui = *StyleUI();
  if (ui.IsInert()) {
    return StylePointerEvents::None;
  }
  return ui.ComputedPointerEvents();
}

StyleUserSelect ComputedStyle::UserSelect() const {
  return StyleUI()->IsInert() ? StyleUserSelect::None
                              : StyleUIReset()->ComputedUserSelect();
}

bool ComputedStyle::IsFixedPosContainingBlockForNonSVGTextFrames() const {
  // NOTE: Any CSS properties that influence the output of this function
  // should return FIXPOS_CB_NON_SVG for will-change.
  if (IsRootElementStyle()) {
    return false;
  }

  const auto& disp = *StyleDisplay();
  if (disp.mWillChange.bits & mozilla::StyleWillChangeBits::FIXPOS_CB_NON_SVG) {
    return true;
  }

  const auto& effects = *StyleEffects();
  return effects.HasFilters() || effects.HasBackdropFilters();
}

bool ComputedStyle::IsFixedPosContainingBlock(
    const nsIFrame* aContextFrame) const {
  // NOTE: Any CSS properties that influence the output of this function
  // should also handle will-change appropriately.
  if (aContextFrame->IsInSVGTextSubtree()) {
    return false;
  }
  if (IsFixedPosContainingBlockForNonSVGTextFrames()) {
    return true;
  }
  const auto& disp = *StyleDisplay();
  if (disp.IsFixedPosContainingBlockForContainLayoutAndPaintSupportingFrames() &&
      aContextFrame->SupportsContainLayoutAndPaint()) {
    return true;
  }
  if (disp.IsFixedPosContainingBlockForTransformSupportingFrames() &&
      aContextFrame->SupportsCSSTransforms()) {
    return true;
  }
  return false;
}

bool ComputedStyle::IsAbsPosContainingBlock(
    const nsIFrame* aContextFrame) const {
  if (IsFixedPosContainingBlock(aContextFrame)) {
    return true;
  }
  // NOTE: Any CSS properties that influence the output of this function
  // should also handle will-change appropriately.
  return StyleDisplay()->IsPositionedStyle() &&
         !aContextFrame->IsInSVGTextSubtree();
}

template <typename Func>
void CachedInheritingStyles::ForEachLazyPseudoEntry(Func&& aFunc) const {
  if (IsEmpty()) {
    return;
  }
  if (IsNullDirect()) {
    aFunc(nullptr, nullptr, NullDirectType());
    return;
  }
  if (!IsIndirect()) {
    ComputedStyle* direct = AsDirect();
    if (direct->IsLazilyCascadedPseudoElement()) {
      aFunc(direct, nullptr, direct->GetPseudoType());
    }
    return;
  }
  for (const auto& entry : *AsIndirect()) {
    if (!entry.mStyle) {
      if (PseudoStyle::IsPseudoElement(entry.mPseudoType) &&
          !PseudoStyle::IsEagerlyCascadedInServo(entry.mPseudoType)) {
        aFunc(nullptr, entry.mFunctionalPseudoParameter.get(),
              entry.mPseudoType);
      }
      continue;
    }
    if (entry.mStyle->IsLazilyCascadedPseudoElement()) {
      aFunc(entry.mStyle.get(), entry.mFunctionalPseudoParameter.get(),
            entry.mPseudoType);
    }
  }
}

template <typename Func>
void ComputedStyle::ForEachCachedLazyPseudoEntry(Func&& aFunc) const {
  mCachedInheritingStyles.ForEachLazyPseudoEntry(aFunc);
}

}  // namespace mozilla

#endif  // ComputedStyleInlines_h