gecko-dev/layout/style/ServoBindings.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 "mozilla/ServoBindings.h"

#include "StyleStructContext.h"
#include "gfxFontFamilyList.h"
#include "nsAttrValueInlines.h"
#include "nsCSSRuleProcessor.h"
#include "nsContentUtils.h"
#include "nsDOMTokenList.h"
#include "nsIDOMNode.h"
#include "nsIDocument.h"
#include "nsINode.h"
#include "nsIPrincipal.h"
#include "nsNameSpaceManager.h"
#include "nsString.h"
#include "nsStyleStruct.h"
#include "nsStyleUtil.h"
#include "nsTArray.h"

#include "mozilla/EventStates.h"
#include "mozilla/ServoElementSnapshot.h"
#include "mozilla/dom/Element.h"

uint32_t
Gecko_ChildrenCount(RawGeckoNode* aNode)
{
  return aNode->GetChildCount();
}

bool
Gecko_NodeIsElement(RawGeckoNode* aNode)
{
  return aNode->IsElement();
}

RawGeckoNode*
Gecko_GetParentNode(RawGeckoNode* aNode)
{
  return aNode->GetParentNode();
}

RawGeckoNode*
Gecko_GetFirstChild(RawGeckoNode* aNode)
{
  return aNode->GetFirstChild();
}

RawGeckoNode*
Gecko_GetLastChild(RawGeckoNode* aNode)
{
  return aNode->GetLastChild();
}

RawGeckoNode*
Gecko_GetPrevSibling(RawGeckoNode* aNode)
{
  return aNode->GetPreviousSibling();
}

RawGeckoNode*
Gecko_GetNextSibling(RawGeckoNode* aNode)
{
  return aNode->GetNextSibling();
}

RawGeckoElement*
Gecko_GetParentElement(RawGeckoElement* aElement)
{
  return aElement->GetParentElement();
}

RawGeckoElement*
Gecko_GetFirstChildElement(RawGeckoElement* aElement)
{
  return aElement->GetFirstElementChild();
}

RawGeckoElement* Gecko_GetLastChildElement(RawGeckoElement* aElement)
{
  return aElement->GetLastElementChild();
}

RawGeckoElement*
Gecko_GetPrevSiblingElement(RawGeckoElement* aElement)
{
  return aElement->GetPreviousElementSibling();
}

RawGeckoElement*
Gecko_GetNextSiblingElement(RawGeckoElement* aElement)
{
  return aElement->GetNextElementSibling();
}

RawGeckoElement*
Gecko_GetDocumentElement(RawGeckoDocument* aDoc)
{
  return aDoc->GetDocumentElement();
}

EventStates::ServoType
Gecko_ElementState(RawGeckoElement* aElement)
{
  return aElement->StyleState().ServoValue();
}

bool
Gecko_IsHTMLElementInHTMLDocument(RawGeckoElement* aElement)
{
  return aElement->IsHTMLElement() && aElement->OwnerDoc()->IsHTMLDocument();
}

bool
Gecko_IsLink(RawGeckoElement* aElement)
{
  return nsCSSRuleProcessor::IsLink(aElement);
}

bool
Gecko_IsTextNode(RawGeckoNode* aNode)
{
  return aNode->NodeInfo()->NodeType() == nsIDOMNode::TEXT_NODE;
}

bool
Gecko_IsVisitedLink(RawGeckoElement* aElement)
{
  return aElement->StyleState().HasState(NS_EVENT_STATE_VISITED);
}

bool
Gecko_IsUnvisitedLink(RawGeckoElement* aElement)
{
  return aElement->StyleState().HasState(NS_EVENT_STATE_UNVISITED);
}

bool
Gecko_IsRootElement(RawGeckoElement* aElement)
{
  return aElement->OwnerDoc()->GetRootElement() == aElement;
}

nsIAtom*
Gecko_LocalName(RawGeckoElement* aElement)
{
  return aElement->NodeInfo()->NameAtom();
}

nsIAtom*
Gecko_Namespace(RawGeckoElement* aElement)
{
  int32_t id = aElement->NodeInfo()->NamespaceID();
  return nsContentUtils::NameSpaceManager()->NameSpaceURIAtom(id);
}

nsIAtom*
Gecko_GetElementId(RawGeckoElement* aElement)
{
  const nsAttrValue* attr = aElement->GetParsedAttr(nsGkAtoms::id);
  return attr ? attr->GetAtomValue() : nullptr;
}

// Dirtiness tracking.
uint32_t
Gecko_GetNodeFlags(RawGeckoNode* aNode)
{
  return aNode->GetFlags();
}

void
Gecko_SetNodeFlags(RawGeckoNode* aNode, uint32_t aFlags)
{
  aNode->SetFlags(aFlags);
}

void
Gecko_UnsetNodeFlags(RawGeckoNode* aNode, uint32_t aFlags)
{
  aNode->UnsetFlags(aFlags);
}

ServoDeclarationBlock*
Gecko_GetServoDeclarationBlock(RawGeckoElement* aElement)
{
  const nsAttrValue* attr = aElement->GetParsedAttr(nsGkAtoms::style);
  if (!attr || attr->Type() != nsAttrValue::eServoCSSDeclaration) {
    return nullptr;
  }
  return attr->GetServoCSSDeclarationValue();
}

template <typename Implementor>
static nsIAtom*
AtomAttrValue(Implementor* aElement, nsIAtom* aName)
{
  const nsAttrValue* attr = aElement->GetParsedAttr(aName);
  return attr ? attr->GetAtomValue() : nullptr;
}

template <typename Implementor, typename MatchFn>
static bool
DoMatch(Implementor* aElement, nsIAtom* aNS, nsIAtom* aName, MatchFn aMatch)
{
  if (aNS) {
    int32_t ns = nsContentUtils::NameSpaceManager()->GetNameSpaceID(aNS);
    NS_ENSURE_TRUE(ns != kNameSpaceID_Unknown, false);
    const nsAttrValue* value = aElement->GetParsedAttr(aName, ns);
    return value && aMatch(value);
  }
  // No namespace means any namespace - we have to check them all. :-(
  BorrowedAttrInfo attrInfo;
  for (uint32_t i = 0; (attrInfo = aElement->GetAttrInfoAt(i)); ++i) {
    if (attrInfo.mName->LocalName() != aName) {
      continue;
    }
    if (aMatch(attrInfo.mValue)) {
      return true;
    }
  }
  return false;
}

// Work around our overly-restrictive static analysis. This can be removed once
// bug 1281935 lands.
template<typename T>
struct FakeRef {
  MOZ_IMPLICIT FakeRef(T* aPtr) : mPtr(aPtr) {}
  operator T*() const { return mPtr; }
  T* mPtr;
};

template <typename Implementor>
static bool
HasAttr(Implementor* aElement, nsIAtom* aNS, nsIAtom* aName)
{
  auto match = [](const nsAttrValue* aValue) { return true; };
  return DoMatch(aElement, aNS, aName, match);
}

template <typename Implementor>
static bool
AttrEquals(Implementor* aElement, nsIAtom* aNS, nsIAtom* aName, nsIAtom* aStr_,
           bool aIgnoreCase)
{
  FakeRef<nsIAtom> aStr(aStr_);
  auto match = [aStr, aIgnoreCase](const nsAttrValue* aValue) {
    return aValue->Equals(aStr, aIgnoreCase ? eIgnoreCase : eCaseMatters);
  };
  return DoMatch(aElement, aNS, aName, match);
}

template <typename Implementor>
static bool
AttrDashEquals(Implementor* aElement, nsIAtom* aNS, nsIAtom* aName,
               nsIAtom* aStr_)
{
  FakeRef<nsIAtom> aStr(aStr_);
  auto match = [aStr](const nsAttrValue* aValue) {
    nsAutoString str;
    aValue->ToString(str);
    const nsDefaultStringComparator c;
    return nsStyleUtil::DashMatchCompare(str, nsDependentAtomString(aStr), c);
  };
  return DoMatch(aElement, aNS, aName, match);
}

template <typename Implementor>
static bool
AttrIncludes(Implementor* aElement, nsIAtom* aNS, nsIAtom* aName,
             nsIAtom* aStr_)
{
  FakeRef<nsIAtom> aStr(aStr_);
  auto match = [aStr](const nsAttrValue* aValue) {
    nsAutoString str;
    aValue->ToString(str);
    const nsDefaultStringComparator c;
    return nsStyleUtil::ValueIncludes(str, nsDependentAtomString(aStr), c);
  };
  return DoMatch(aElement, aNS, aName, match);
}

template <typename Implementor>
static bool
AttrHasSubstring(Implementor* aElement, nsIAtom* aNS, nsIAtom* aName,
                 nsIAtom* aStr_)
{
  FakeRef<nsIAtom> aStr(aStr_);
  auto match = [aStr](const nsAttrValue* aValue) {
    nsAutoString str;
    aValue->ToString(str);
    return FindInReadable(str, nsDependentAtomString(aStr));
  };
  return DoMatch(aElement, aNS, aName, match);
}

template <typename Implementor>
static bool
AttrHasPrefix(Implementor* aElement, nsIAtom* aNS, nsIAtom* aName,
              nsIAtom* aStr_)
{
  FakeRef<nsIAtom> aStr(aStr_);
  auto match = [aStr](const nsAttrValue* aValue) {
    nsAutoString str;
    aValue->ToString(str);
    return StringBeginsWith(str, nsDependentAtomString(aStr));
  };
  return DoMatch(aElement, aNS, aName, match);
}

template <typename Implementor>
static bool
AttrHasSuffix(Implementor* aElement, nsIAtom* aNS, nsIAtom* aName,
              nsIAtom* aStr_)
{
  FakeRef<nsIAtom> aStr(aStr_);
  auto match = [aStr](const nsAttrValue* aValue) {
    nsAutoString str;
    aValue->ToString(str);
    return StringEndsWith(str, nsDependentAtomString(aStr));
  };
  return DoMatch(aElement, aNS, aName, match);
}

/**
 * Gets the class or class list (if any) of the implementor. The calling
 * convention here is rather hairy, and is optimized for getting Servo the
 * information it needs for hot calls.
 *
 * The return value indicates the number of classes. If zero, neither outparam
 * is valid. If one, the class_ outparam is filled with the atom of the class.
 * If two or more, the classList outparam is set to point to an array of atoms
 * representing the class list.
 *
 * The array is borrowed and the atoms are not addrefed. These values can be
 * invalidated by any DOM mutation. Use them in a tight scope.
 */
template <typename Implementor>
static uint32_t
ClassOrClassList(Implementor* aElement, nsIAtom** aClass, nsIAtom*** aClassList)
{
  const nsAttrValue* attr = aElement->GetParsedAttr(nsGkAtoms::_class);
  if (!attr) {
    return 0;
  }

  // For class values with only whitespace, Gecko just stores a string. For the
  // purposes of the style system, there is no class in this case.
  if (attr->Type() == nsAttrValue::eString) {
    MOZ_ASSERT(nsContentUtils::TrimWhitespace<nsContentUtils::IsHTMLWhitespace>(
                 attr->GetStringValue()).IsEmpty());
    return 0;
  }

  // Single tokens are generally stored as an atom. Check that case.
  if (attr->Type() == nsAttrValue::eAtom) {
    *aClass = attr->GetAtomValue();
    return 1;
  }

  // At this point we should have an atom array. It is likely, but not
  // guaranteed, that we have two or more elements in the array.
  MOZ_ASSERT(attr->Type() == nsAttrValue::eAtomArray);
  nsTArray<nsCOMPtr<nsIAtom>>* atomArray = attr->GetAtomArrayValue();
  uint32_t length = atomArray->Length();

  // Special case: zero elements.
  if (length == 0) {
    return 0;
  }

  // Special case: one element.
  if (length == 1) {
    *aClass = atomArray->ElementAt(0);
    return 1;
  }

  // General case: Two or more elements.
  //
  // Note: We could also expose this array as an array of nsCOMPtrs, since
  // bindgen knows what those look like, and eliminate the reinterpret_cast.
  // But it's not obvious that that would be preferable.
  static_assert(sizeof(nsCOMPtr<nsIAtom>) == sizeof(nsIAtom*), "Bad simplification");
  static_assert(alignof(nsCOMPtr<nsIAtom>) == alignof(nsIAtom*), "Bad simplification");

  nsCOMPtr<nsIAtom>* elements = atomArray->Elements();
  nsIAtom** rawElements = reinterpret_cast<nsIAtom**>(elements);
  *aClassList = rawElements;
  return atomArray->Length();
}

#define SERVO_IMPL_ELEMENT_ATTR_MATCHING_FUNCTIONS(prefix_, implementor_)      \
  nsIAtom* prefix_##AtomAttrValue(implementor_* aElement, nsIAtom* aName)      \
  {                                                                            \
    return AtomAttrValue(aElement, aName);                                     \
  }                                                                            \
  bool prefix_##HasAttr(implementor_* aElement, nsIAtom* aNS, nsIAtom* aName)  \
  {                                                                            \
    return HasAttr(aElement, aNS, aName);                                      \
  }                                                                            \
  bool prefix_##AttrEquals(implementor_* aElement, nsIAtom* aNS,               \
                           nsIAtom* aName, nsIAtom* aStr, bool aIgnoreCase)    \
  {                                                                            \
    return AttrEquals(aElement, aNS, aName, aStr, aIgnoreCase);                \
  }                                                                            \
  bool prefix_##AttrDashEquals(implementor_* aElement, nsIAtom* aNS,           \
                               nsIAtom* aName, nsIAtom* aStr)                  \
  {                                                                            \
    return AttrDashEquals(aElement, aNS, aName, aStr);                         \
  }                                                                            \
  bool prefix_##AttrIncludes(implementor_* aElement, nsIAtom* aNS,             \
                             nsIAtom* aName, nsIAtom* aStr)                    \
  {                                                                            \
    return AttrIncludes(aElement, aNS, aName, aStr);                           \
  }                                                                            \
  bool prefix_##AttrHasSubstring(implementor_* aElement, nsIAtom* aNS,         \
                                 nsIAtom* aName, nsIAtom* aStr)                \
  {                                                                            \
    return AttrHasSubstring(aElement, aNS, aName, aStr);                       \
  }                                                                            \
  bool prefix_##AttrHasPrefix(implementor_* aElement, nsIAtom* aNS,            \
                              nsIAtom* aName, nsIAtom* aStr)                   \
  {                                                                            \
    return AttrHasPrefix(aElement, aNS, aName, aStr);                          \
  }                                                                            \
  bool prefix_##AttrHasSuffix(implementor_* aElement, nsIAtom* aNS,            \
                              nsIAtom* aName, nsIAtom* aStr)                   \
  {                                                                            \
    return AttrHasSuffix(aElement, aNS, aName, aStr);                          \
  }                                                                            \
  uint32_t prefix_##ClassOrClassList(implementor_* aElement, nsIAtom** aClass, \
                                     nsIAtom*** aClassList)                    \
  {                                                                            \
    return ClassOrClassList(aElement, aClass, aClassList);                     \
  }

SERVO_IMPL_ELEMENT_ATTR_MATCHING_FUNCTIONS(Gecko_, RawGeckoElement)
SERVO_IMPL_ELEMENT_ATTR_MATCHING_FUNCTIONS(Gecko_Snapshot, ServoElementSnapshot)

#undef SERVO_IMPL_ELEMENT_ATTR_MATCHING_FUNCTIONS

ServoNodeData*
Gecko_GetNodeData(RawGeckoNode* aNode)
{
  return aNode->GetServoNodeData();
}

void
Gecko_SetNodeData(RawGeckoNode* aNode, ServoNodeData* aData)
{
  aNode->SetServoNodeData(aData);
}

nsIAtom*
Gecko_Atomize(const char* aString, uint32_t aLength)
{
  return NS_Atomize(nsDependentCSubstring(aString, aLength)).take();
}

void
Gecko_AddRefAtom(nsIAtom* aAtom)
{
  NS_ADDREF(aAtom);
}

void
Gecko_ReleaseAtom(nsIAtom* aAtom)
{
  NS_RELEASE(aAtom);
}

const uint16_t*
Gecko_GetAtomAsUTF16(nsIAtom* aAtom, uint32_t* aLength)
{
  static_assert(sizeof(char16_t) == sizeof(uint16_t), "Servo doesn't know what a char16_t is");
  MOZ_ASSERT(aAtom);
  *aLength = aAtom->GetLength();

  // We need to manually cast from char16ptr_t to const char16_t* to handle the
  // MOZ_USE_CHAR16_WRAPPER we use on WIndows.
  return reinterpret_cast<const uint16_t*>(static_cast<const char16_t*>(aAtom->GetUTF16String()));
}

bool
Gecko_AtomEqualsUTF8(nsIAtom* aAtom, const char* aString, uint32_t aLength)
{
  // XXXbholley: We should be able to do this without converting, I just can't
  // find the right thing to call.
  nsAutoString atomStr;
  aAtom->ToString(atomStr);
  NS_ConvertUTF8toUTF16 inStr(nsDependentCSubstring(aString, aLength));
  return atomStr.Equals(inStr);
}

bool
Gecko_AtomEqualsUTF8IgnoreCase(nsIAtom* aAtom, const char* aString, uint32_t aLength)
{
  // XXXbholley: We should be able to do this without converting, I just can't
  // find the right thing to call.
  nsAutoString atomStr;
  aAtom->ToString(atomStr);
  NS_ConvertUTF8toUTF16 inStr(nsDependentCSubstring(aString, aLength));
  return nsContentUtils::EqualsIgnoreASCIICase(atomStr, inStr);
}

void
Gecko_FontFamilyList_Clear(FontFamilyList* aList) {
  aList->Clear();
}

void
Gecko_FontFamilyList_AppendNamed(FontFamilyList* aList, nsIAtom* aName)
{
  // Servo doesn't record whether the name was quoted or unquoted, so just
  // assume unquoted for now.
  FontFamilyName family;
  aName->ToString(family.mName);
  aList->Append(family);
}

void
Gecko_FontFamilyList_AppendGeneric(FontFamilyList* aList, FontFamilyType aType)
{
  aList->Append(FontFamilyName(aType));
}

void
Gecko_CopyFontFamilyFrom(nsFont* dst, const nsFont* src)
{
  dst->fontlist = src->fontlist;
}

void
Gecko_SetListStyleType(nsStyleList* style_struct, uint32_t type)
{
  // Builtin counter styles are static and use no-op refcounting, and thus are
  // safe to use off-main-thread.
  style_struct->SetCounterStyle(CounterStyleManager::GetBuiltinStyle(type));
}

void
Gecko_CopyListStyleTypeFrom(nsStyleList* dst, const nsStyleList* src)
{
  dst->SetCounterStyle(src->GetCounterStyle());
}

NS_IMPL_HOLDER_FFI_REFCOUNTING(nsIPrincipal, Principal)
NS_IMPL_HOLDER_FFI_REFCOUNTING(nsIURI, URI)

void
Gecko_SetMozBinding(nsStyleDisplay* aDisplay,
                    const uint8_t* aURLString, uint32_t aURLStringLength,
                    ThreadSafeURIHolder* aBaseURI,
                    ThreadSafeURIHolder* aReferrer,
                    ThreadSafePrincipalHolder* aPrincipal)
{
  MOZ_ASSERT(aDisplay);
  MOZ_ASSERT(aURLString);
  MOZ_ASSERT(aBaseURI);
  MOZ_ASSERT(aReferrer);
  MOZ_ASSERT(aPrincipal);

  nsString url;
  nsDependentCSubstring urlString(reinterpret_cast<const char*>(aURLString),
                                  aURLStringLength);
  AppendUTF8toUTF16(urlString, url);
  RefPtr<nsStringBuffer> urlBuffer = nsCSSValue::BufferFromString(url);

  aDisplay->mBinding =
    new css::URLValue(urlBuffer, do_AddRef(aBaseURI),
                      do_AddRef(aReferrer), do_AddRef(aPrincipal));
}

void
Gecko_CopyMozBindingFrom(nsStyleDisplay* aDest, const nsStyleDisplay* aSrc)
{
  aDest->mBinding = aSrc->mBinding;
}


void
Gecko_SetNullImageValue(nsStyleImage* aImage)
{
  MOZ_ASSERT(aImage);
  aImage->SetNull();
}

void
Gecko_SetGradientImageValue(nsStyleImage* aImage, nsStyleGradient* aGradient)
{
  MOZ_ASSERT(aImage);
  aImage->SetGradientData(aGradient);
}

void
Gecko_CopyImageValueFrom(nsStyleImage* aImage, const nsStyleImage* aOther)
{
  MOZ_ASSERT(aImage);
  MOZ_ASSERT(aOther);

  *aImage = *aOther;
}

nsStyleGradient*
Gecko_CreateGradient(uint8_t aShape,
                     uint8_t aSize,
                     bool aRepeating,
                     bool aLegacySyntax,
                     uint32_t aStopCount)
{
  nsStyleGradient* result = new nsStyleGradient();

  result->mShape = aShape;
  result->mSize = aSize;
  result->mRepeating = aRepeating;
  result->mLegacySyntax = aLegacySyntax;

  result->mAngle.SetNoneValue();
  result->mBgPosX.SetNoneValue();
  result->mBgPosY.SetNoneValue();
  result->mRadiusX.SetNoneValue();
  result->mRadiusY.SetNoneValue();

  nsStyleGradientStop dummyStop;
  dummyStop.mLocation.SetNoneValue();
  dummyStop.mColor = NS_RGB(0, 0, 0);
  dummyStop.mIsInterpolationHint = 0;

  for (uint32_t i = 0; i < aStopCount; i++) {
    result->mStops.AppendElement(dummyStop);
  }

  return result;
}

void
Gecko_EnsureTArrayCapacity(void* aArray, size_t aCapacity, size_t aElemSize)
{
  auto base = reinterpret_cast<nsTArray_base<nsTArrayInfallibleAllocator, nsTArray_CopyWithMemutils> *>(aArray);
  base->EnsureCapacity<nsTArrayInfallibleAllocator>(aCapacity, aElemSize);
}

void
Gecko_EnsureImageLayersLength(nsStyleImageLayers* aLayers, size_t aLen)
{
  aLayers->mLayers.EnsureLengthAtLeast(aLen);
}

void
Gecko_InitializeImageLayer(nsStyleImageLayers::Layer* aLayer,
                                nsStyleImageLayers::LayerType aLayerType)
{
  aLayer->Initialize(aLayerType);
}

void
Gecko_ResetStyleCoord(nsStyleUnit* aUnit, nsStyleUnion* aValue)
{
  nsStyleCoord::Reset(*aUnit, *aValue);
}

void
Gecko_SetStyleCoordCalcValue(nsStyleUnit* aUnit, nsStyleUnion* aValue, nsStyleCoord::CalcValue aCalc)
{
  // Calc units should be cleaned up first
  MOZ_ASSERT(*aUnit != nsStyleUnit::eStyleUnit_Calc);
  nsStyleCoord::Calc* calcRef = new nsStyleCoord::Calc();
  calcRef->mLength = aCalc.mLength;
  calcRef->mPercent = aCalc.mPercent;
  calcRef->mHasPercent = aCalc.mHasPercent;
  *aUnit = nsStyleUnit::eStyleUnit_Calc;
  aValue->mPointer = calcRef;
  calcRef->AddRef();
}

NS_IMPL_THREADSAFE_FFI_REFCOUNTING(nsStyleCoord::Calc, Calc);

#define STYLE_STRUCT(name, checkdata_cb)                                      \
                                                                              \
void                                                                          \
Gecko_Construct_nsStyle##name(nsStyle##name* ptr)                             \
{                                                                             \
  new (ptr) nsStyle##name(StyleStructContext::ServoContext());                \
}                                                                             \
                                                                              \
void                                                                          \
Gecko_CopyConstruct_nsStyle##name(nsStyle##name* ptr,                         \
                                  const nsStyle##name* other)                 \
{                                                                             \
  new (ptr) nsStyle##name(*other);                                            \
}                                                                             \
                                                                              \
void                                                                          \
Gecko_Destroy_nsStyle##name(nsStyle##name* ptr)                               \
{                                                                             \
  ptr->~nsStyle##name();                                                      \
}

#include "nsStyleStructList.h"

#undef STYLE_STRUCT

#ifndef MOZ_STYLO
void
Servo_DropNodeData(ServoNodeData* data)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_DropNodeData in a "
            "non-MOZ_STYLO build");
}

RawServoStyleSheet*
Servo_StylesheetFromUTF8Bytes(const uint8_t* bytes, uint32_t length,
                              mozilla::css::SheetParsingMode mode,
                              ThreadSafeURIHolder* base,
                              ThreadSafeURIHolder* referrer,
                              ThreadSafePrincipalHolder* principal)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_StylesheetFromUTF8Bytes in a "
            "non-MOZ_STYLO build");
}

void
Servo_AddRefStyleSheet(RawServoStyleSheet* sheet)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_AddRefStylesheet in a "
            "non-MOZ_STYLO build");
}

void
Servo_ReleaseStyleSheet(RawServoStyleSheet* sheet)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_ReleaseStylesheet in a "
            "non-MOZ_STYLO build");
}

void
Servo_AppendStyleSheet(RawServoStyleSheet* sheet, RawServoStyleSet* set)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_AppendStyleSheet in a "
            "non-MOZ_STYLO build");
}

void Servo_PrependStyleSheet(RawServoStyleSheet* sheet, RawServoStyleSet* set)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_PrependStyleSheet in a "
            "non-MOZ_STYLO build");
}

void Servo_RemoveStyleSheet(RawServoStyleSheet* sheet, RawServoStyleSet* set)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_RemoveStyleSheet in a "
            "non-MOZ_STYLO build");
}

void
Servo_InsertStyleSheetBefore(RawServoStyleSheet* sheet,
                             RawServoStyleSheet* reference,
                             RawServoStyleSet* set)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_InsertStyleSheetBefore in a "
            "non-MOZ_STYLO build");
}

bool
Servo_StyleSheetHasRules(RawServoStyleSheet* sheet)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_StyleSheetHasRules in a "
            "non-MOZ_STYLO build");
}

RawServoStyleSet*
Servo_InitStyleSet()
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_InitStyleSet in a "
            "non-MOZ_STYLO build");
}

void
Servo_DropStyleSet(RawServoStyleSet* set)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_DropStyleSet in a "
            "non-MOZ_STYLO build");
}

ServoDeclarationBlock*
Servo_ParseStyleAttribute(const uint8_t* bytes, uint32_t length,
                          nsHTMLCSSStyleSheet* cache)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_ParseStyleAttribute in a "
            "non-MOZ_STYLO build");
}

void
Servo_DropDeclarationBlock(ServoDeclarationBlock* declarations)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_DropDeclarationBlock in a "
            "non-MOZ_STYLO build");
}

nsHTMLCSSStyleSheet*
Servo_GetDeclarationBlockCache(ServoDeclarationBlock* declarations)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_GetDeclarationBlockCache in a "
            "non-MOZ_STYLO build");
}

void
Servo_SetDeclarationBlockImmutable(ServoDeclarationBlock* declarations)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_SetDeclarationBlockImmutable in a "
            "non-MOZ_STYLO build");
}

void
Servo_ClearDeclarationBlockCachePointer(ServoDeclarationBlock* declarations)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_ClearDeclarationBlockCachePointer in a "
            "non-MOZ_STYLO build");
}

bool
Servo_CSSSupports(const uint8_t* name, uint32_t name_length,
                  const uint8_t* value, uint32_t value_length)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_CSSSupports in a "
            "non-MOZ_STYLO build");
}

ServoComputedValues*
Servo_GetComputedValues(RawGeckoNode* node)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_GetComputedValues in a "
            "non-MOZ_STYLO build");
}

ServoComputedValues*
Servo_GetComputedValuesForAnonymousBox(ServoComputedValues* parentStyleOrNull,
                                       nsIAtom* pseudoTag,
                                       RawServoStyleSet* set)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_GetComputedValuesForAnonymousBox in a "
            "non-MOZ_STYLO build");
}

ServoComputedValues*
Servo_GetComputedValuesForPseudoElement(ServoComputedValues* parent_style,
                                        RawGeckoElement* match_element,
                                        nsIAtom* pseudo_tag,
                                        RawServoStyleSet* set,
                                        bool is_probe)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_GetComputedValuesForPseudoElement in a "
            "non-MOZ_STYLO build");
}

ServoComputedValues*
Servo_InheritComputedValues(ServoComputedValues* parent_style)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_InheritComputedValues in a "
            "non-MOZ_STYLO build");
}

void
Servo_AddRefComputedValues(ServoComputedValues*)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_AddRefComputedValues in a "
            "non-MOZ_STYLO build");
}

void
Servo_ReleaseComputedValues(ServoComputedValues*)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_ReleaseComputedValues in a "
            "non-MOZ_STYLO build");
}

void
Servo_Initialize()
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_Initialize in a "
            "non-MOZ_STYLO build");
}

// Restyle hints.
nsRestyleHint
Servo_ComputeRestyleHint(RawGeckoElement* element,
                         ServoElementSnapshot* snapshot, RawServoStyleSet* set)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_ComputeRestyleHint in a "
            "non-MOZ_STYLO build");
}

void
Servo_RestyleDocument(RawGeckoDocument* doc, RawServoStyleSet* set)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_RestyleDocument in a "
            "non-MOZ_STYLO build");
}

void Servo_RestyleSubtree(RawGeckoNode* node, RawServoStyleSet* set)
{
  MOZ_CRASH("stylo: shouldn't be calling Servo_RestyleSubtree in a "
            "non-MOZ_STYLO build");
}

#define STYLE_STRUCT(name_, checkdata_cb_)                                     \
const nsStyle##name_*                                                          \
Servo_GetStyle##name_(ServoComputedValues*)                                    \
{                                                                              \
  MOZ_CRASH("stylo: shouldn't be calling Servo_GetStyle" #name_ " in a "       \
            "non-MOZ_STYLO build");                                            \
}
#include "nsStyleStructList.h"
#undef STYLE_STRUCT
#endif

#ifdef MOZ_STYLO
const nsStyleVariables*
Servo_GetStyleVariables(ServoComputedValues* aComputedValues)
{
  // Servo can't provide us with Variables structs yet, so instead of linking
  // to a Servo_GetStyleVariables defined in Servo we define one here that
  // always returns the same, empty struct.
  static nsStyleVariables variables(StyleStructContext::ServoContext());
  return &variables;
}
#endif