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gecko-dev/layout/style/nsStyleContext.cpp

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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/. */
/* the interface (to internal code) for retrieving computed style data */
#include "nsStyleContext.h"
#include "CSSVariableImageTable.h"
#include "mozilla/DebugOnly.h"
#include "mozilla/Maybe.h"
#include "nsCSSAnonBoxes.h"
#include "nsCSSPseudoElements.h"
#include "nsFontMetrics.h"
#include "nsStyleConsts.h"
#include "nsStyleStruct.h"
#include "nsStyleStructInlines.h"
#include "nsString.h"
#include "nsPresContext.h"
#include "nsIStyleRule.h"
#include "nsCOMPtr.h"
#include "nsStyleSet.h"
#include "nsIPresShell.h"
#include "nsRuleNode.h"
#include "GeckoProfiler.h"
#include "nsIDocument.h"
#include "nsPrintfCString.h"
#include "RubyUtils.h"
#include "mozilla/Preferences.h"
#include "mozilla/ArenaObjectID.h"
#include "mozilla/StyleSetHandle.h"
#include "mozilla/StyleSetHandleInlines.h"
#include "mozilla/ReflowInput.h"
#include "nsLayoutUtils.h"
#include "nsCoord.h"
// Ensure the binding function declarations in nsStyleContext.h matches
// those in ServoBindings.h.
#include "mozilla/ServoBindings.h"
using namespace mozilla;
//----------------------------------------------------------------------
#ifdef DEBUG
// Check that the style struct IDs are in the same order as they are
// in nsStyleStructList.h, since when we set up the IDs, we include
// the inherited and reset structs spearately from nsStyleStructList.h
enum DebugStyleStruct {
#define STYLE_STRUCT(name, checkdata_cb) eDebugStyleStruct_##name,
#include "nsStyleStructList.h"
#undef STYLE_STRUCT
};
#define STYLE_STRUCT(name, checkdata_cb) \
static_assert(static_cast<int>(eDebugStyleStruct_##name) == \
static_cast<int>(eStyleStruct_##name), \
"Style struct IDs are not declared in order?");
#include "nsStyleStructList.h"
#undef STYLE_STRUCT
const uint32_t nsStyleContext::sDependencyTable[] = {
#define STYLE_STRUCT(name, checkdata_cb)
#define STYLE_STRUCT_DEP(dep) NS_STYLE_INHERIT_BIT(dep) |
#define STYLE_STRUCT_END() 0,
#include "nsStyleStructList.h"
#undef STYLE_STRUCT
#undef STYLE_STRUCT_DEP
#undef STYLE_STRUCT_END
};
// Whether to perform expensive assertions in the nsStyleContext destructor.
static bool sExpensiveStyleStructAssertionsEnabled;
#endif
nsStyleContext::nsStyleContext(nsStyleContext* aParent,
OwningStyleContextSource&& aSource,
nsIAtom* aPseudoTag,
CSSPseudoElementType aPseudoType)
: mParent(aParent)
, mChild(nullptr)
, mEmptyChild(nullptr)
, mPseudoTag(aPseudoTag)
, mSource(Move(aSource))
#ifdef MOZ_STYLO
, mPresContext(nullptr)
#endif
, mCachedResetData(nullptr)
, mBits(((uint64_t)aPseudoType) << NS_STYLE_CONTEXT_TYPE_SHIFT)
, mRefCnt(0)
#ifdef DEBUG
, mFrameRefCnt(0)
, mComputingStruct(nsStyleStructID_None)
#endif
{}
nsStyleContext::nsStyleContext(nsStyleContext* aParent,
nsIAtom* aPseudoTag,
CSSPseudoElementType aPseudoType,
already_AddRefed<nsRuleNode> aRuleNode,
bool aSkipParentDisplayBasedStyleFixup)
: nsStyleContext(aParent, OwningStyleContextSource(Move(aRuleNode)),
aPseudoTag, aPseudoType)
{
#ifdef MOZ_STYLO
mPresContext = mSource.AsGeckoRuleNode()->PresContext();
#endif
if (aParent) {
#ifdef DEBUG
nsRuleNode *r1 = mParent->RuleNode(), *r2 = mSource.AsGeckoRuleNode();
while (r1->GetParent())
r1 = r1->GetParent();
while (r2->GetParent())
r2 = r2->GetParent();
NS_ASSERTION(r1 == r2, "must be in the same rule tree as parent");
#endif
} else {
PresContext()->PresShell()->StyleSet()->RootStyleContextAdded();
}
mSource.AsGeckoRuleNode()->SetUsedDirectly(); // before ApplyStyleFixups()!
FinishConstruction();
ApplyStyleFixups(aSkipParentDisplayBasedStyleFixup);
}
nsStyleContext::nsStyleContext(nsStyleContext* aParent,
nsPresContext* aPresContext,
nsIAtom* aPseudoTag,
CSSPseudoElementType aPseudoType,
already_AddRefed<ServoComputedValues> aComputedValues)
: nsStyleContext(aParent, OwningStyleContextSource(Move(aComputedValues)),
aPseudoTag, aPseudoType)
{
#ifdef MOZ_STYLO
mPresContext = aPresContext;
#endif
FinishConstruction();
// No need to call ApplyStyleFixups here, since fixups are handled by Servo when
// producing the ServoComputedValues.
}
void
nsStyleContext::FinishConstruction()
{
// This check has to be done "backward", because if it were written the
// more natural way it wouldn't fail even when it needed to.
static_assert((UINT64_MAX >> NS_STYLE_CONTEXT_TYPE_SHIFT) >=
static_cast<CSSPseudoElementTypeBase>(
CSSPseudoElementType::MAX),
"pseudo element bits no longer fit in a uint64_t");
MOZ_ASSERT(!mSource.IsNull());
#ifdef DEBUG
static_assert(MOZ_ARRAY_LENGTH(nsStyleContext::sDependencyTable)
== nsStyleStructID_Length,
"Number of items in dependency table doesn't match IDs");
#endif
mNextSibling = this;
mPrevSibling = this;
if (mParent) {
mParent->AddChild(this);
}
SetStyleBits();
#define eStyleStruct_LastItem (nsStyleStructID_Length - 1)
static_assert(NS_STYLE_INHERIT_MASK & NS_STYLE_INHERIT_BIT(LastItem),
"NS_STYLE_INHERIT_MASK must be bigger, and other bits shifted");
#undef eStyleStruct_LastItem
}
nsStyleContext::~nsStyleContext()
{
NS_ASSERTION((nullptr == mChild) && (nullptr == mEmptyChild), "destructing context with children");
MOZ_ASSERT(!mSource.IsServoComputedValues() || !mCachedResetData);
#ifdef DEBUG
if (mSource.IsServoComputedValues()) {
MOZ_ASSERT(!mCachedResetData,
"Servo shouldn't cache reset structs in nsStyleContext");
for (const auto* data : mCachedInheritedData.mStyleStructs) {
MOZ_ASSERT(!data,
"Servo shouldn't cache inherit structs in nsStyleContext");
}
}
if (sExpensiveStyleStructAssertionsEnabled) {
// Assert that the style structs we are about to destroy are not referenced
// anywhere else in the style context tree. These checks are expensive,
// which is why they are not enabled by default.
nsStyleContext* root = this;
while (root->mParent) {
root = root->mParent;
}
root->AssertStructsNotUsedElsewhere(this,
std::numeric_limits<int32_t>::max());
} else {
// In DEBUG builds when the pref is not enabled, we perform a more limited
// check just of the children of this style context.
AssertStructsNotUsedElsewhere(this, 2);
}
#endif
nsPresContext *presContext = PresContext();
DebugOnly<nsStyleSet*> geckoStyleSet = presContext->PresShell()->StyleSet()->GetAsGecko();
NS_ASSERTION(!geckoStyleSet ||
geckoStyleSet->GetRuleTree() == mSource.AsGeckoRuleNode()->RuleTree() ||
geckoStyleSet->IsInRuleTreeReconstruct(),
"destroying style context from old rule tree too late");
if (mParent) {
mParent->RemoveChild(this);
} else {
presContext->StyleSet()->RootStyleContextRemoved();
}
// Free up our data structs.
mCachedInheritedData.DestroyStructs(mBits, presContext);
if (mCachedResetData) {
mCachedResetData->Destroy(mBits, presContext);
}
// Free any ImageValues we were holding on to for CSS variable values.
CSSVariableImageTable::RemoveAll(this);
}
#ifdef DEBUG
void
nsStyleContext::AssertStructsNotUsedElsewhere(
nsStyleContext* aDestroyingContext,
int32_t aLevels) const
{
if (aLevels == 0) {
return;
}
void* data;
if (mBits & NS_STYLE_IS_GOING_AWAY) {
return;
}
if (this != aDestroyingContext) {
nsInheritedStyleData& destroyingInheritedData =
aDestroyingContext->mCachedInheritedData;
#define STYLE_STRUCT_INHERITED(name_, checkdata_cb) \
data = destroyingInheritedData.mStyleStructs[eStyleStruct_##name_]; \
if (data && \
!(aDestroyingContext->mBits & NS_STYLE_INHERIT_BIT(name_)) && \
(mCachedInheritedData.mStyleStructs[eStyleStruct_##name_] == data)) { \
printf_stderr("style struct %p found on style context %p\n", data, this);\
nsString url; \
nsresult rv = PresContext()->Document()->GetURL(url); \
if (NS_SUCCEEDED(rv)) { \
printf_stderr(" in %s\n", NS_ConvertUTF16toUTF8(url).get()); \
} \
MOZ_ASSERT(false, "destroying " #name_ " style struct still present " \
"in style context tree"); \
}
#define STYLE_STRUCT_RESET(name_, checkdata_cb)
#include "nsStyleStructList.h"
#undef STYLE_STRUCT_INHERITED
#undef STYLE_STRUCT_RESET
if (mCachedResetData) {
nsResetStyleData* destroyingResetData =
aDestroyingContext->mCachedResetData;
if (destroyingResetData) {
#define STYLE_STRUCT_INHERITED(name_, checkdata_cb_)
#define STYLE_STRUCT_RESET(name_, checkdata_cb) \
data = destroyingResetData->mStyleStructs[eStyleStruct_##name_]; \
if (data && \
!(aDestroyingContext->mBits & NS_STYLE_INHERIT_BIT(name_)) && \
(mCachedResetData->mStyleStructs[eStyleStruct_##name_] == data)) { \
printf_stderr("style struct %p found on style context %p\n", data, \
this); \
nsString url; \
nsresult rv = PresContext()->Document()->GetURL(url); \
if (NS_SUCCEEDED(rv)) { \
printf_stderr(" in %s\n", NS_ConvertUTF16toUTF8(url).get()); \
} \
MOZ_ASSERT(false, "destroying " #name_ " style struct still present "\
"in style context tree"); \
}
#include "nsStyleStructList.h"
#undef STYLE_STRUCT_INHERITED
#undef STYLE_STRUCT_RESET
}
}
}
if (mChild) {
const nsStyleContext* child = mChild;
do {
child->AssertStructsNotUsedElsewhere(aDestroyingContext, aLevels - 1);
child = child->mNextSibling;
} while (child != mChild);
}
if (mEmptyChild) {
const nsStyleContext* child = mEmptyChild;
do {
child->AssertStructsNotUsedElsewhere(aDestroyingContext, aLevels - 1);
child = child->mNextSibling;
} while (child != mEmptyChild);
}
}
#endif
void nsStyleContext::AddChild(nsStyleContext* aChild)
{
NS_ASSERTION(aChild->mPrevSibling == aChild &&
aChild->mNextSibling == aChild,
"child already in a child list");
nsStyleContext **listPtr = aChild->mSource.MatchesNoRules() ? &mEmptyChild : &mChild;
// Explicitly dereference listPtr so that compiler doesn't have to know that mNextSibling
// etc. don't alias with what ever listPtr points at.
nsStyleContext *list = *listPtr;
// Insert at the beginning of the list. See also FindChildWithRules.
if (list) {
// Link into existing elements, if there are any.
aChild->mNextSibling = list;
aChild->mPrevSibling = list->mPrevSibling;
list->mPrevSibling->mNextSibling = aChild;
list->mPrevSibling = aChild;
}
(*listPtr) = aChild;
}
void nsStyleContext::RemoveChild(nsStyleContext* aChild)
{
NS_PRECONDITION(nullptr != aChild && this == aChild->mParent, "bad argument");
nsStyleContext **list = aChild->mSource.MatchesNoRules() ? &mEmptyChild : &mChild;
if (aChild->mPrevSibling != aChild) { // has siblings
if ((*list) == aChild) {
(*list) = (*list)->mNextSibling;
}
}
else {
NS_ASSERTION((*list) == aChild, "bad sibling pointers");
(*list) = nullptr;
}
aChild->mPrevSibling->mNextSibling = aChild->mNextSibling;
aChild->mNextSibling->mPrevSibling = aChild->mPrevSibling;
aChild->mNextSibling = aChild;
aChild->mPrevSibling = aChild;
}
void
nsStyleContext::MoveTo(nsStyleContext* aNewParent)
{
MOZ_ASSERT(aNewParent != mParent);
// This function shouldn't be getting called if the parents have different
// values for some flags in mBits (unless the flag is also set on this style
// context) because if that were the case we would need to recompute those
// bits for |this|.
#define CHECK_FLAG(bit_) \
MOZ_ASSERT((mParent->mBits & (bit_)) == (aNewParent->mBits & (bit_)) || \
(mBits & (bit_)), \
"MoveTo cannot be called if " #bit_ " value on old and new " \
"style context parents do not match, unless the flag is set " \
"on this style context");
CHECK_FLAG(NS_STYLE_HAS_PSEUDO_ELEMENT_DATA)
CHECK_FLAG(NS_STYLE_IN_DISPLAY_NONE_SUBTREE)
CHECK_FLAG(NS_STYLE_HAS_TEXT_DECORATION_LINES)
CHECK_FLAG(NS_STYLE_RELEVANT_LINK_VISITED)
#undef CHECK_FLAG
// Assertions checking for visited style are just to avoid some tricky
// cases we can't be bothered handling at the moment.
MOZ_ASSERT(!IsStyleIfVisited());
MOZ_ASSERT(!mParent->IsStyleIfVisited());
MOZ_ASSERT(!aNewParent->IsStyleIfVisited());
MOZ_ASSERT(!mStyleIfVisited || mStyleIfVisited->mParent == mParent);
if (mParent->HasChildThatUsesResetStyle()) {
aNewParent->AddStyleBit(NS_STYLE_HAS_CHILD_THAT_USES_RESET_STYLE);
}
mParent->RemoveChild(this);
mParent = aNewParent;
mParent->AddChild(this);
if (mStyleIfVisited) {
mStyleIfVisited->mParent->RemoveChild(mStyleIfVisited);
mStyleIfVisited->mParent = aNewParent;
mStyleIfVisited->mParent->AddChild(mStyleIfVisited);
}
}
already_AddRefed<nsStyleContext>
nsStyleContext::FindChildWithRules(const nsIAtom* aPseudoTag,
NonOwningStyleContextSource aSource,
NonOwningStyleContextSource aSourceIfVisited,
bool aRelevantLinkVisited)
{
uint32_t threshold = 10; // The # of siblings we're willing to examine
// before just giving this whole thing up.
RefPtr<nsStyleContext> result;
nsStyleContext *list = aSource.MatchesNoRules() ? mEmptyChild : mChild;
if (list) {
nsStyleContext *child = list;
do {
if (child->mSource.AsRaw() == aSource &&
child->mPseudoTag == aPseudoTag &&
!child->IsStyleIfVisited() &&
child->RelevantLinkVisited() == aRelevantLinkVisited) {
bool match = false;
if (!aSourceIfVisited.IsNull()) {
match = child->GetStyleIfVisited() &&
child->GetStyleIfVisited()->mSource.AsRaw() == aSourceIfVisited;
} else {
match = !child->GetStyleIfVisited();
}
if (match && !(child->mBits & NS_STYLE_INELIGIBLE_FOR_SHARING)) {
result = child;
break;
}
}
child = child->mNextSibling;
threshold--;
if (threshold == 0)
break;
} while (child != list);
}
if (result) {
if (result != list) {
// Move result to the front of the list.
RemoveChild(result);
AddChild(result);
}
result->mBits |= NS_STYLE_IS_SHARED;
}
return result.forget();
}
const void* nsStyleContext::StyleData(nsStyleStructID aSID)
{
const void* cachedData = GetCachedStyleData(aSID);
if (cachedData)
return cachedData; // We have computed data stored on this node in the context tree.
// Our style source will take care of it for us.
const void* newData;
if (mSource.IsGeckoRuleNode()) {
newData = mSource.AsGeckoRuleNode()->GetStyleData(aSID, this, true);
if (!nsCachedStyleData::IsReset(aSID)) {
// always cache inherited data on the style context; the rule
// node set the bit in mBits for us if needed.
mCachedInheritedData.mStyleStructs[aSID] = const_cast<void*>(newData);
}
} else {
newData = StyleStructFromServoComputedValues(aSID);
// perform any remaining main thread work on the struct
switch (aSID) {
#define STYLE_STRUCT(name_, checkdata_cb_) \
case eStyleStruct_##name_: { \
auto data = static_cast<const nsStyle##name_*>(newData); \
const_cast<nsStyle##name_*>(data)->FinishStyle(PresContext()); \
break; \
}
#include "nsStyleStructList.h"
#undef STYLE_STRUCT
default:
MOZ_ASSERT_UNREACHABLE("unexpected nsStyleStructID value");
break;
}
// The Servo-backed StyleContextSource owns the struct.
AddStyleBit(nsCachedStyleData::GetBitForSID(aSID));
// XXXbholley: Unconditionally caching reset structs here defeats the memory
// optimization where we lazily allocate mCachedResetData, so that we can avoid
// performing an FFI call each time we want to get the style structs. We should
// measure the tradeoffs at some point. If the FFI overhead is low and the memory
// win significant, we should consider _always_ grabbing the struct over FFI, and
// potentially giving mCachedInheritedData the same treatment.
//
// Note that there is a similar comment in the struct getters in nsStyleContext.h.
SetStyle(aSID, const_cast<void*>(newData));
}
return newData;
}
// This is an evil evil function, since it forces you to alloc your own separate copy of
// style data! Do not use this function unless you absolutely have to! You should avoid
// this at all costs! -dwh
void*
nsStyleContext::GetUniqueStyleData(const nsStyleStructID& aSID)
{
MOZ_ASSERT(!mSource.IsServoComputedValues(),
"Can't COW-mutate servo values from Gecko!");
// If we already own the struct and no kids could depend on it, then
// just return it. (We leak in this case if there are kids -- and this
// function really shouldn't be called for style contexts that could
// have kids depending on the data. ClearStyleData would be OK, but
// this test for no mChild or mEmptyChild doesn't catch that case.)
const void *current = StyleData(aSID);
if (!mChild && !mEmptyChild &&
!(mBits & nsCachedStyleData::GetBitForSID(aSID)) &&
GetCachedStyleData(aSID))
return const_cast<void*>(current);
void* result;
nsPresContext *presContext = PresContext();
switch (aSID) {
#define UNIQUE_CASE(c_) \
case eStyleStruct_##c_: \
result = new (presContext) nsStyle##c_( \
* static_cast<const nsStyle##c_ *>(current)); \
break;
UNIQUE_CASE(Font)
UNIQUE_CASE(Display)
UNIQUE_CASE(Text)
UNIQUE_CASE(TextReset)
UNIQUE_CASE(Visibility)
#undef UNIQUE_CASE
default:
NS_ERROR("Struct type not supported. Please find another way to do this if you can!");
return nullptr;
}
SetStyle(aSID, result);
mBits &= ~static_cast<uint64_t>(nsCachedStyleData::GetBitForSID(aSID));
return result;
}
// This is an evil function, but less evil than GetUniqueStyleData. It
// creates an empty style struct for this nsStyleContext.
void*
nsStyleContext::CreateEmptyStyleData(const nsStyleStructID& aSID)
{
MOZ_ASSERT(!mChild && !mEmptyChild &&
!(mBits & nsCachedStyleData::GetBitForSID(aSID)) &&
!GetCachedStyleData(aSID),
"This style should not have been computed");
void* result;
nsPresContext* presContext = PresContext();
switch (aSID) {
#define UNIQUE_CASE(c_) \
case eStyleStruct_##c_: \
result = new (presContext) nsStyle##c_(presContext); \
break;
UNIQUE_CASE(Border)
UNIQUE_CASE(Padding)
#undef UNIQUE_CASE
default:
NS_ERROR("Struct type not supported.");
return nullptr;
}
// The new struct is owned by this style context, but that we don't
// need to clear the bit in mBits because we've asserted that at the
// top of this function.
SetStyle(aSID, result);
return result;
}
void
nsStyleContext::SetStyle(nsStyleStructID aSID, void* aStruct)
{
MOZ_ASSERT(!mSource.IsServoComputedValues(),
"Servo shouldn't cache style structs in the style context!");
// This method should only be called from nsRuleNode! It is not a public
// method!
NS_ASSERTION(aSID >= 0 && aSID < nsStyleStructID_Length, "out of bounds");
// NOTE: nsCachedStyleData::GetStyleData works roughly the same way.
// See the comments there (in nsRuleNode.h) for more details about
// what this is doing and why.
void** dataSlot;
if (nsCachedStyleData::IsReset(aSID)) {
if (!mCachedResetData) {
mCachedResetData = new (PresContext()) nsResetStyleData;
}
dataSlot = &mCachedResetData->mStyleStructs[aSID];
} else {
dataSlot = &mCachedInheritedData.mStyleStructs[aSID];
}
NS_ASSERTION(!*dataSlot || (mBits & nsCachedStyleData::GetBitForSID(aSID)),
"Going to leak style data");
*dataSlot = aStruct;
}
static bool
ShouldSuppressLineBreak(const nsStyleContext* aContext,
const nsStyleDisplay* aDisplay,
const nsStyleContext* aParentContext,
const nsStyleDisplay* aParentDisplay)
{
// The display change should only occur for "in-flow" children
if (aDisplay->IsOutOfFlowStyle()) {
return false;
}
// Display value of any anonymous box should not be touched. In most
// cases, anonymous boxes are actually not in ruby frame, but instead,
// some other frame with a ruby display value. Non-element pseudos
// which represents text frames, as well as ruby pseudos are excluded
// because we still want to set the flag for them.
if ((aContext->GetPseudoType() == CSSPseudoElementType::InheritingAnonBox ||
aContext->GetPseudoType() == CSSPseudoElementType::NonInheritingAnonBox) &&
!nsCSSAnonBoxes::IsNonElement(aContext->GetPseudo()) &&
!RubyUtils::IsRubyPseudo(aContext->GetPseudo())) {
return false;
}
if (aParentContext->ShouldSuppressLineBreak()) {
// Line break suppressing bit is propagated to any children of
// line participants, which include inline, contents, and inline
// ruby boxes.
if (aParentDisplay->mDisplay == mozilla::StyleDisplay::Inline ||
aParentDisplay->mDisplay == mozilla::StyleDisplay::Contents ||
aParentDisplay->mDisplay == mozilla::StyleDisplay::Ruby ||
aParentDisplay->mDisplay == mozilla::StyleDisplay::RubyBaseContainer) {
return true;
}
}
// Any descendant of ruby level containers is non-breakable, but
// the level containers themselves are breakable. We have to check
// the container display type against all ruby display type here
// because any of the ruby boxes could be anonymous.
// Note that, when certain HTML tags, e.g. form controls, have ruby
// level container display type, they could also escape from this flag
// while they shouldn't. However, it is generally fine since they
// won't usually break the assertion that there is no line break
// inside ruby, because:
// 1. their display types, the ruby level container types, are inline-
// outside, which means they won't cause any forced line break; and
// 2. they never start an inline span, which means their children, if
// any, won't be able to break the line its ruby ancestor lays; and
// 3. their parent frame is always a ruby content frame (due to
// anonymous ruby box generation), which makes line layout suppress
// any optional line break around this frame.
// However, there is one special case which is BR tag, because it
// directly affects the line layout. This case is handled by the BR
// frame which checks the flag of its parent frame instead of itself.
if ((aParentDisplay->IsRubyDisplayType() &&
aDisplay->mDisplay != mozilla::StyleDisplay::RubyBaseContainer &&
aDisplay->mDisplay != mozilla::StyleDisplay::RubyTextContainer) ||
// Since ruby base and ruby text may exist themselves without any
// non-anonymous frame outside, we should also check them.
aDisplay->mDisplay == mozilla::StyleDisplay::RubyBase ||
aDisplay->mDisplay == mozilla::StyleDisplay::RubyText) {
return true;
}
return false;
}
// Flex & grid containers blockify their children.
// "The display value of a flex item is blockified"
// https://drafts.csswg.org/css-flexbox-1/#flex-items
// "The display value of a grid item is blockified"
// https://drafts.csswg.org/css-grid/#grid-items
static bool
ShouldBlockifyChildren(const nsStyleDisplay* aStyleDisp)
{
auto displayVal = aStyleDisp->mDisplay;
return mozilla::StyleDisplay::Flex == displayVal ||
mozilla::StyleDisplay::InlineFlex == displayVal ||
mozilla::StyleDisplay::Grid == displayVal ||
mozilla::StyleDisplay::InlineGrid == displayVal;
}
void
nsStyleContext::SetStyleBits()
{
// Here we set up various style bits for both the Gecko and Servo paths.
// _Only_ change the bits here. For fixups of the computed values, you can
// add to ApplyStyleFixups in Gecko and StyleAdjuster as part of Servo's
// cascade.
// See if we have any text decorations.
// First see if our parent has text decorations. If our parent does, then we inherit the bit.
if (mParent && mParent->HasTextDecorationLines()) {
AddStyleBit(NS_STYLE_HAS_TEXT_DECORATION_LINES);
} else {
// We might have defined a decoration.
if (StyleTextReset()->HasTextDecorationLines()) {
AddStyleBit(NS_STYLE_HAS_TEXT_DECORATION_LINES);
}
}
if ((mParent && mParent->HasPseudoElementData()) || IsPseudoElement()) {
AddStyleBit(NS_STYLE_HAS_PSEUDO_ELEMENT_DATA);
}
// Set the NS_STYLE_IN_DISPLAY_NONE_SUBTREE bit
const nsStyleDisplay* disp = StyleDisplay();
if ((mParent && mParent->IsInDisplayNoneSubtree()) ||
disp->mDisplay == mozilla::StyleDisplay::None) {
AddStyleBit(NS_STYLE_IN_DISPLAY_NONE_SUBTREE);
}
// Mark text combined for text-combine-upright, as needed.
if (mPseudoTag == nsCSSAnonBoxes::mozText && mParent &&
mParent->StyleVisibility()->mWritingMode !=
NS_STYLE_WRITING_MODE_HORIZONTAL_TB &&
mParent->StyleText()->mTextCombineUpright ==
NS_STYLE_TEXT_COMBINE_UPRIGHT_ALL) {
AddStyleBit(NS_STYLE_IS_TEXT_COMBINED);
}
}
void
nsStyleContext::ApplyStyleFixups(bool aSkipParentDisplayBasedStyleFixup)
{
MOZ_ASSERT(!mSource.IsServoComputedValues(),
"Can't do Gecko style fixups on Servo values");
#define GET_UNIQUE_STYLE_DATA(name_) \
static_cast<nsStyle##name_*>(GetUniqueStyleData(eStyleStruct_##name_))
// CSS Inline Layout Level 3 - 3.5 Sizing Initial Letters:
// For an N-line drop initial in a Western script, the cap-height of the
// letter needs to be (N – 1) times the line-height, plus the cap-height
// of the surrounding text.
if (mPseudoTag == nsCSSPseudoElements::firstLetter) {
const nsStyleTextReset* textReset = StyleTextReset();
if (textReset->mInitialLetterSize != 0.0f) {
nsStyleContext* containerSC = mParent;
const nsStyleDisplay* containerDisp = containerSC->StyleDisplay();
while (containerDisp->mDisplay == mozilla::StyleDisplay::Contents) {
if (!containerSC->GetParent()) {
break;
}
containerSC = containerSC->GetParent();
containerDisp = containerSC->StyleDisplay();
}
nscoord containerLH =
ReflowInput::CalcLineHeight(nullptr, containerSC, NS_AUTOHEIGHT, 1.0f);
RefPtr<nsFontMetrics> containerFM =
nsLayoutUtils::GetFontMetricsForStyleContext(containerSC);
MOZ_ASSERT(containerFM, "Should have fontMetrics!!");
nscoord containerCH = containerFM->CapHeight();
RefPtr<nsFontMetrics> firstLetterFM =
nsLayoutUtils::GetFontMetricsForStyleContext(this);
MOZ_ASSERT(firstLetterFM, "Should have fontMetrics!!");
nscoord firstLetterCH = firstLetterFM->CapHeight();
nsStyleFont* mutableStyleFont = GET_UNIQUE_STYLE_DATA(Font);
float invCapHeightRatio =
mutableStyleFont->mFont.size / NSCoordToFloat(firstLetterCH);
mutableStyleFont->mFont.size =
NSToCoordRound(((textReset->mInitialLetterSize - 1) * containerLH +
containerCH) *
invCapHeightRatio);
}
}
// Change writing mode of text frame for text-combine-upright. We use
// style structs of the parent to avoid triggering computation before
// we change the writing mode.
// It is safe to look at the parent's style because we are looking at
// inherited properties, and ::-moz-text never matches any rules.
if (mPseudoTag == nsCSSAnonBoxes::mozText && mParent &&
mParent->StyleVisibility()->mWritingMode !=
NS_STYLE_WRITING_MODE_HORIZONTAL_TB &&
mParent->StyleText()->mTextCombineUpright ==
NS_STYLE_TEXT_COMBINE_UPRIGHT_ALL) {
MOZ_ASSERT(!PeekStyleVisibility(), "If StyleVisibility was already "
"computed, some properties may have been computed "
"incorrectly based on the old writing mode value");
nsStyleVisibility* mutableVis = GET_UNIQUE_STYLE_DATA(Visibility);
mutableVis->mWritingMode = NS_STYLE_WRITING_MODE_HORIZONTAL_TB;
}
// CSS 2.1 10.1: Propagate the root element's 'direction' to the ICB.
// (PageContentFrame/CanvasFrame etc will inherit 'direction')
if (mPseudoTag == nsCSSAnonBoxes::viewport) {
nsPresContext* presContext = PresContext();
mozilla::dom::Element* docElement = presContext->Document()->GetRootElement();
if (docElement) {
RefPtr<nsStyleContext> rootStyle =
presContext->StyleSet()->AsGecko()->ResolveStyleFor(docElement, nullptr);
auto dir = rootStyle->StyleVisibility()->mDirection;
if (dir != StyleVisibility()->mDirection) {
nsStyleVisibility* uniqueVisibility = GET_UNIQUE_STYLE_DATA(Visibility);
uniqueVisibility->mDirection = dir;
}
}
}
// Correct tables.
const nsStyleDisplay* disp = StyleDisplay();
if (disp->mDisplay == mozilla::StyleDisplay::Table) {
// -moz-center and -moz-right are used for HTML's alignment
// This is covering the <div align="right"><table>...</table></div> case.
// In this case, we don't want to inherit the text alignment into the table.
const nsStyleText* text = StyleText();
if (text->mTextAlign == NS_STYLE_TEXT_ALIGN_MOZ_LEFT ||
text->mTextAlign == NS_STYLE_TEXT_ALIGN_MOZ_CENTER ||
text->mTextAlign == NS_STYLE_TEXT_ALIGN_MOZ_RIGHT)
{
nsStyleText* uniqueText = GET_UNIQUE_STYLE_DATA(Text);
uniqueText->mTextAlign = NS_STYLE_TEXT_ALIGN_START;
}
}
// CSS2.1 section 9.2.4 specifies fixups for the 'display' property of
// the root element. We can't implement them in nsRuleNode because we
// don't want to store all display structs that aren't 'block',
// 'inline', or 'table' in the style context tree on the off chance
// that the root element has its style reresolved later. So do them
// here if needed, by changing the style data, so that other code
// doesn't get confused by looking at the style data.
if (!mParent &&
// We don't want to blockify various anon boxes that just happen to not
// inherit from anything. So restrict blockification only to actual
// elements, the viewport (which should be block anyway, but in SVG
// document's isn't because we lazy-load ua.css there), and the ::backdrop
// pseudo-element. This last is explicitly allowed to have any specified
// display type in the spec, but computes to a blockified display type per
// various provisions of
// https://fullscreen.spec.whatwg.org/#new-stacking-layer
(!mPseudoTag ||
mPseudoTag == nsCSSAnonBoxes::viewport ||
mPseudoTag == nsCSSPseudoElements::backdrop)) {
auto displayVal = disp->mDisplay;
if (displayVal != mozilla::StyleDisplay::Contents) {
nsRuleNode::EnsureBlockDisplay(displayVal, true);
} else {
// http://dev.w3.org/csswg/css-display/#transformations
// "... a display-outside of 'contents' computes to block-level
// on the root element."
displayVal = mozilla::StyleDisplay::Block;
}
if (displayVal != disp->mDisplay) {
nsStyleDisplay* mutable_display = GET_UNIQUE_STYLE_DATA(Display);
disp = mutable_display;
// If we're in this code, then mOriginalDisplay doesn't matter
// for purposes of the cascade (because this nsStyleDisplay
// isn't living in the ruletree anyway), and for determining
// hypothetical boxes it's better to have mOriginalDisplay
// matching mDisplay here.
mutable_display->mOriginalDisplay = mutable_display->mDisplay =
displayVal;
}
}
// Adjust the "display" values of flex and grid items (but not for raw text
// or placeholders). CSS3 Flexbox section 4 says:
// # The computed 'display' of a flex item is determined
// # by applying the table in CSS 2.1 Chapter 9.7.
// ...which converts inline-level elements to their block-level equivalents.
// Any block-level element directly contained by elements with ruby display
// values are converted to their inline-level equivalents.
if (!aSkipParentDisplayBasedStyleFixup && mParent) {
// Skip display:contents ancestors to reach the potential container.
// (If there are only display:contents ancestors between this node and
// a flex/grid container ancestor, then this node is a flex/grid item, since
// its parent *in the frame tree* will be the flex/grid container. So we treat
// it like a flex/grid item here.)
nsStyleContext* containerContext = mParent;
const nsStyleDisplay* containerDisp = containerContext->StyleDisplay();
while (containerDisp->mDisplay == mozilla::StyleDisplay::Contents) {
if (!containerContext->GetParent()) {
break;
}
containerContext = containerContext->GetParent();
containerDisp = containerContext->StyleDisplay();
}
if (ShouldBlockifyChildren(containerDisp) &&
!nsCSSAnonBoxes::IsNonElement(GetPseudo())) {
// NOTE: Technically, we shouldn't modify the 'display' value of
// positioned elements, since they aren't flex/grid items. However,
// we don't need to worry about checking for that, because if we're
// positioned, we'll have already been through a call to
// EnsureBlockDisplay() in nsRuleNode, so this call here won't change
// anything. So we're OK.
auto displayVal = disp->mDisplay;
nsRuleNode::EnsureBlockDisplay(displayVal);
if (displayVal != disp->mDisplay) {
NS_ASSERTION(!disp->IsAbsolutelyPositionedStyle(),
"We shouldn't be changing the display value of "
"positioned content (and we should have already "
"converted its display value to be block-level...)");
nsStyleDisplay* mutable_display = GET_UNIQUE_STYLE_DATA(Display);
disp = mutable_display;
mutable_display->mDisplay = displayVal;
}
}
}
// Note: This must come after the blockification above, otherwise we fail
// the grid-item-blockifying-001.html reftest.
if (mParent && ::ShouldSuppressLineBreak(this, disp, mParent,
mParent->StyleDisplay())) {
mBits |= NS_STYLE_SUPPRESS_LINEBREAK;
auto displayVal = disp->mDisplay;
nsRuleNode::EnsureInlineDisplay(displayVal);
if (displayVal != disp->mDisplay) {
nsStyleDisplay* mutable_display = GET_UNIQUE_STYLE_DATA(Display);
disp = mutable_display;
mutable_display->mDisplay = displayVal;
}
}
// Suppress border/padding of ruby level containers
if (disp->mDisplay == mozilla::StyleDisplay::RubyBaseContainer ||
disp->mDisplay == mozilla::StyleDisplay::RubyTextContainer) {
CreateEmptyStyleData(eStyleStruct_Border);
CreateEmptyStyleData(eStyleStruct_Padding);
}
if (disp->IsRubyDisplayType()) {
// Per CSS Ruby spec section Bidi Reordering, for all ruby boxes,
// the 'normal' and 'embed' values of 'unicode-bidi' should compute to
// 'isolate', and 'bidi-override' should compute to 'isolate-override'.
const nsStyleTextReset* textReset = StyleTextReset();
uint8_t unicodeBidi = textReset->mUnicodeBidi;
if (unicodeBidi == NS_STYLE_UNICODE_BIDI_NORMAL ||
unicodeBidi == NS_STYLE_UNICODE_BIDI_EMBED) {
unicodeBidi = NS_STYLE_UNICODE_BIDI_ISOLATE;
} else if (unicodeBidi == NS_STYLE_UNICODE_BIDI_BIDI_OVERRIDE) {
unicodeBidi = NS_STYLE_UNICODE_BIDI_ISOLATE_OVERRIDE;
}
if (unicodeBidi != textReset->mUnicodeBidi) {
nsStyleTextReset* mutableTextReset = GET_UNIQUE_STYLE_DATA(TextReset);
mutableTextReset->mUnicodeBidi = unicodeBidi;
}
}
/*
* According to https://drafts.csswg.org/css-writing-modes-3/#block-flow:
*
* If a box has a different block flow direction than its containing block:
* * If the box has a specified display of inline, its display computes
* to inline-block. [CSS21]
* ...etc.
*/
if (disp->mDisplay == mozilla::StyleDisplay::Inline &&
!nsCSSAnonBoxes::IsNonElement(mPseudoTag) &&
mParent) {
auto cbContext = mParent;
while (cbContext->StyleDisplay()->mDisplay == mozilla::StyleDisplay::Contents) {
cbContext = cbContext->mParent;
}
MOZ_ASSERT(cbContext, "the root context can't have display:contents");
// We don't need the full mozilla::WritingMode value (incorporating dir
// and text-orientation) here; just the writing-mode property is enough.
if (StyleVisibility()->mWritingMode !=
cbContext->StyleVisibility()->mWritingMode) {
nsStyleDisplay* mutable_display = GET_UNIQUE_STYLE_DATA(Display);
disp = mutable_display;
mutable_display->mOriginalDisplay = mutable_display->mDisplay =
mozilla::StyleDisplay::InlineBlock;
}
}
// Compute User Interface style, to trigger loads of cursors
StyleUserInterface();
#undef GET_UNIQUE_STYLE_DATA
}
template<class StyleContextLike>
nsChangeHint
nsStyleContext::CalcStyleDifferenceInternal(StyleContextLike* aNewContext,
uint32_t* aEqualStructs,
uint32_t* aSamePointerStructs)
{
PROFILER_LABEL("nsStyleContext", "CalcStyleDifference",
js::ProfileEntry::Category::CSS);
static_assert(nsStyleStructID_Length <= 32,
"aEqualStructs is not big enough");
*aEqualStructs = 0;
nsChangeHint hint = nsChangeHint(0);
NS_ENSURE_TRUE(aNewContext, hint);
// We must always ensure that we populate the structs on the new style
// context that are filled in on the old context, so that if we get
// two style changes in succession, the second of which causes a real
// style change, the PeekStyleData doesn't return null (implying that
// nobody ever looked at that struct's data). In other words, we
// can't skip later structs if we get a big change up front, because
// we could later get a small change in one of those structs that we
// don't want to miss.
DebugOnly<uint32_t> structsFound = 0;
// FIXME(heycam): We should just do the comparison in
// nsStyleVariables::CalcDifference, returning NeutralChange if there are
// any Variables differences.
const nsStyleVariables* thisVariables = PeekStyleVariables();
if (thisVariables) {
structsFound |= NS_STYLE_INHERIT_BIT(Variables);
const nsStyleVariables* otherVariables = aNewContext->StyleVariables();
if (thisVariables->mVariables == otherVariables->mVariables) {
*aEqualStructs |= NS_STYLE_INHERIT_BIT(Variables);
}
} else {
*aEqualStructs |= NS_STYLE_INHERIT_BIT(Variables);
}
DebugOnly<int> styleStructCount = 1; // count Variables already
// Servo's optimization to stop the cascade when there are no style changes
// that children need to be recascade for relies on comparing all of the
// structs, not just those that are returned from PeekStyleData, although
// if PeekStyleData does return null we still don't want to accumulate
// any change hints for those structs.
bool checkUnrequestedServoStructs = mSource.IsServoComputedValues();
#define DO_STRUCT_DIFFERENCE(struct_) \
PR_BEGIN_MACRO \
const nsStyle##struct_* this##struct_ = PeekStyle##struct_(); \
bool unrequestedStruct; \
if (this##struct_) { \
unrequestedStruct = false; \
structsFound |= NS_STYLE_INHERIT_BIT(struct_); \
} else if (checkUnrequestedServoStructs) { \
this##struct_ = \
Servo_GetStyle##struct_(mSource.AsServoComputedValues()); \
unrequestedStruct = true; \
} else { \
unrequestedStruct = false; \
} \
if (this##struct_) { \
const nsStyle##struct_* other##struct_ = aNewContext->Style##struct_(); \
if (this##struct_ == other##struct_) { \
/* The very same struct, so we know that there will be no */ \
/* differences. */ \
*aEqualStructs |= NS_STYLE_INHERIT_BIT(struct_); \
} else { \
nsChangeHint difference = \
this##struct_->CalcDifference(*other##struct_ EXTRA_DIFF_ARGS); \
if (!unrequestedStruct) { \
hint |= difference; \
} \
if (!difference) { \
*aEqualStructs |= NS_STYLE_INHERIT_BIT(struct_); \
} \
} \
} else { \
*aEqualStructs |= NS_STYLE_INHERIT_BIT(struct_); \
} \
styleStructCount++; \
PR_END_MACRO
// FIXME: The order of these DO_STRUCT_DIFFERENCE calls is no longer
// significant. With a small amount of effort, we could replace them with a
// #include "nsStyleStructList.h".
#define EXTRA_DIFF_ARGS /* nothing */
DO_STRUCT_DIFFERENCE(Display);
DO_STRUCT_DIFFERENCE(XUL);
DO_STRUCT_DIFFERENCE(Column);
DO_STRUCT_DIFFERENCE(Content);
DO_STRUCT_DIFFERENCE(UserInterface);
DO_STRUCT_DIFFERENCE(Visibility);
DO_STRUCT_DIFFERENCE(Outline);
DO_STRUCT_DIFFERENCE(TableBorder);
DO_STRUCT_DIFFERENCE(Table);
DO_STRUCT_DIFFERENCE(UIReset);
DO_STRUCT_DIFFERENCE(Text);
DO_STRUCT_DIFFERENCE(List);
DO_STRUCT_DIFFERENCE(SVGReset);
DO_STRUCT_DIFFERENCE(SVG);
#undef EXTRA_DIFF_ARGS
#define EXTRA_DIFF_ARGS , PeekStyleVisibility()
DO_STRUCT_DIFFERENCE(Position);
#undef EXTRA_DIFF_ARGS
#define EXTRA_DIFF_ARGS /* nothing */
DO_STRUCT_DIFFERENCE(Font);
DO_STRUCT_DIFFERENCE(Margin);
DO_STRUCT_DIFFERENCE(Padding);
DO_STRUCT_DIFFERENCE(Border);
DO_STRUCT_DIFFERENCE(TextReset);
DO_STRUCT_DIFFERENCE(Effects);
DO_STRUCT_DIFFERENCE(Background);
DO_STRUCT_DIFFERENCE(Color);
#undef EXTRA_DIFF_ARGS
#undef DO_STRUCT_DIFFERENCE
MOZ_ASSERT(styleStructCount == nsStyleStructID_Length,
"missing a call to DO_STRUCT_DIFFERENCE");
#ifdef DEBUG
#define STYLE_STRUCT(name_, callback_) \
MOZ_ASSERT(!!(structsFound & NS_STYLE_INHERIT_BIT(name_)) == \
!!PeekStyle##name_(), \
"PeekStyleData results must not change in the middle of " \
"difference calculation.");
#include "nsStyleStructList.h"
#undef STYLE_STRUCT
#endif
// We check for struct pointer equality here rather than as part of the
// DO_STRUCT_DIFFERENCE calls, since those calls can result in structs
// we previously examined and found to be null on this style context
// getting computed by later DO_STRUCT_DIFFERENCE calls (which can
// happen when the nsRuleNode::ComputeXXXData method looks up another
// struct.) This is important for callers in RestyleManager that
// need to know the equality or not of the final set of cached struct
// pointers.
*aSamePointerStructs = 0;
#define STYLE_STRUCT(name_, callback_) \
{ \
const nsStyle##name_* data = PeekStyle##name_(); \
if (!data || data == aNewContext->Style##name_()) { \
*aSamePointerStructs |= NS_STYLE_INHERIT_BIT(name_); \
} \
}
#include "nsStyleStructList.h"
#undef STYLE_STRUCT
// Note that we do not check whether this->RelevantLinkVisited() !=
// aNewContext->RelevantLinkVisited(); we don't need to since
// nsCSSFrameConstructor::DoContentStateChanged always adds
// nsChangeHint_RepaintFrame for NS_EVENT_STATE_VISITED changes (and
// needs to, since HasStateDependentStyle probably doesn't work right
// for NS_EVENT_STATE_VISITED). Hopefully this doesn't actually
// expose whether links are visited to performance tests since all
// link coloring happens asynchronously at a time when it's hard for
// the page to measure.
// However, we do need to compute the larger of the changes that can
// happen depending on whether the link is visited or unvisited, since
// doing only the one that's currently appropriate would expose which
// links are in history to easy performance measurement. Therefore,
// here, we add nsChangeHint_RepaintFrame hints (the maximum for
// things that can depend on :visited) for the properties on which we
// call GetVisitedDependentColor.
nsStyleContext *thisVis = GetStyleIfVisited(),
*otherVis = aNewContext->GetStyleIfVisited();
if (!thisVis != !otherVis) {
// One style context has a style-if-visited and the other doesn't.
// Presume a difference.
hint |= nsChangeHint_RepaintFrame;
} else if (thisVis && !NS_IsHintSubset(nsChangeHint_RepaintFrame, hint)) {
// Bug 1364484: Update comments here and potentially remove the assertion
// below once we return a non-null visited context in CalcStyleDifference
// using Servo values. The approach is becoming quite similar to Gecko.
// We'll handle visited style differently in servo. Assert against being
// in the parallel traversal to avoid static analysis hazards when calling
// StyleFoo() below.
MOZ_ASSERT(!ServoStyleSet::IsInServoTraversal());
// Both style contexts have a style-if-visited.
bool change = false;
// NB: Calling Peek on |this|, not |thisVis|, since callers may look
// at a struct on |this| without looking at the same struct on
// |thisVis| (including this function if we skip one of these checks
// due to change being true already or due to the old style context
// not having a style-if-visited), but not the other way around.
#define STYLE_FIELD(name_) thisVisStruct->name_ != otherVisStruct->name_
#define STYLE_STRUCT(name_, fields_) \
if (!change && PeekStyle##name_()) { \
const nsStyle##name_* thisVisStruct = thisVis->Style##name_(); \
const nsStyle##name_* otherVisStruct = otherVis->Style##name_(); \
if (MOZ_FOR_EACH_SEPARATED(STYLE_FIELD, (||), (), fields_)) { \
change = true; \
} \
}
#include "nsCSSVisitedDependentPropList.h"
#undef STYLE_STRUCT
#undef STYLE_FIELD
if (change) {
hint |= nsChangeHint_RepaintFrame;
}
}
if (hint & nsChangeHint_UpdateContainingBlock) {
// If a struct returned nsChangeHint_UpdateContainingBlock, that
// means that one property's influence on whether we're a containing
// block for abs-pos or fixed-pos elements has changed. However, we
// only need to return the hint if the overall computation of
// whether we establish a containing block has changed.
// This depends on data in nsStyleDisplay, nsStyleEffects and
// nsStyleSVGReset, so we do it here.
// Note that it's perhaps good for this test to be last because it
// doesn't use Peek* functions to get the structs on the old
// context. But this isn't a big concern because these struct
// getters should be called during frame construction anyway.
if (ThreadsafeStyleDisplay()->IsAbsPosContainingBlockForAppropriateFrame(this) ==
aNewContext->ThreadsafeStyleDisplay()->
IsAbsPosContainingBlockForAppropriateFrame(aNewContext) &&
ThreadsafeStyleDisplay()->IsFixedPosContainingBlockForAppropriateFrame(this) ==
aNewContext->ThreadsafeStyleDisplay()->
IsFixedPosContainingBlockForAppropriateFrame(aNewContext)) {
// While some styles that cause the frame to be a containing block
// has changed, the overall result hasn't.
hint &= ~nsChangeHint_UpdateContainingBlock;
}
}
MOZ_ASSERT(NS_IsHintSubset(hint, nsChangeHint_AllHints),
"Added a new hint without bumping AllHints?");
return hint & ~nsChangeHint_NeutralChange;
}
nsChangeHint
nsStyleContext::CalcStyleDifference(nsStyleContext* aNewContext,
uint32_t* aEqualStructs,
uint32_t* aSamePointerStructs)
{
return CalcStyleDifferenceInternal(aNewContext,
aEqualStructs,
aSamePointerStructs);
}
class MOZ_STACK_CLASS FakeStyleContext
{
public:
explicit FakeStyleContext(const ServoComputedValues* aComputedValues)
: mComputedValues(aComputedValues) {}
mozilla::NonOwningStyleContextSource StyleSource() const {
return mozilla::NonOwningStyleContextSource(mComputedValues);
}
nsStyleContext* GetStyleIfVisited() {
// Bug 1364484: Figure out what to do here for Stylo visited values. We can
// get the visited computed values:
// RefPtr<ServoComputedValues> visitedComputedValues =
// Servo_ComputedValues_GetVisitedStyle(mComputedValues).Consume();
// But what's the best way to create the nsStyleContext?
return nullptr;
}
#define STYLE_STRUCT(name_, checkdata_cb_) \
const nsStyle##name_ * Style##name_() { \
return Servo_GetStyle##name_(mComputedValues); \
} \
const nsStyle##name_ * ThreadsafeStyle##name_() { \
return Servo_GetStyle##name_(mComputedValues); \
}
#include "nsStyleStructList.h"
#undef STYLE_STRUCT
private:
const ServoComputedValues* MOZ_NON_OWNING_REF mComputedValues;
};
nsChangeHint
nsStyleContext::CalcStyleDifference(const ServoComputedValues* aNewComputedValues,
uint32_t* aEqualStructs,
uint32_t* aSamePointerStructs)
{
FakeStyleContext newContext(aNewComputedValues);
return CalcStyleDifferenceInternal(&newContext,
aEqualStructs,
aSamePointerStructs);
}
void
nsStyleContext::EnsureSameStructsCached(nsStyleContext* aOldContext)
{
// NOTE(emilio): We could do better here for stylo, where we only call
// Style##name_() because we need to run FinishStyle, but otherwise this
// is only a bitwise or.
//
// We could reduce the FFI traffic we do only doing it for structs that have
// non-trivial FinishStyle.
#define STYLE_STRUCT(name_, checkdata_cb_) \
if (aOldContext->PeekStyle##name_()) { \
Style##name_(); \
}
#include "nsStyleStructList.h"
#undef STYLE_STRUCT
#ifdef DEBUG
if (mSource.IsServoComputedValues()) {
auto oldMask = aOldContext->mBits & NS_STYLE_INHERIT_MASK;
auto newMask = mBits & NS_STYLE_INHERIT_MASK;
MOZ_ASSERT((oldMask & newMask) == oldMask,
"Should have at least as many structs computed as the "
"old context!");
}
#endif
}
#ifdef DEBUG
void nsStyleContext::List(FILE* out, int32_t aIndent, bool aListDescendants)
{
nsAutoCString str;
// Indent
int32_t ix;
for (ix = aIndent; --ix >= 0; ) {
str.AppendLiteral(" ");
}
str.Append(nsPrintfCString("%p(%d) parent=%p ",
(void*)this, mRefCnt, (void *)mParent));
if (mPseudoTag) {
nsAutoString buffer;
mPseudoTag->ToString(buffer);
AppendUTF16toUTF8(buffer, str);
str.Append(' ');
}
if (mSource.IsServoComputedValues()) {
fprintf_stderr(out, "%s{ServoComputedValues}\n", str.get());
} else if (mSource.IsGeckoRuleNode()) {
fprintf_stderr(out, "%s{\n", str.get());
str.Truncate();
nsRuleNode* ruleNode = mSource.AsGeckoRuleNode();
while (ruleNode) {
nsIStyleRule *styleRule = ruleNode->GetRule();
if (styleRule) {
styleRule->List(out, aIndent + 1);
}
ruleNode = ruleNode->GetParent();
}
for (ix = aIndent; --ix >= 0; ) {
str.AppendLiteral(" ");
}
fprintf_stderr(out, "%s}\n", str.get());
}
else {
fprintf_stderr(out, "%s{}\n", str.get());
}
if (aListDescendants) {
if (nullptr != mChild) {
nsStyleContext* child = mChild;
do {
child->List(out, aIndent + 1, aListDescendants);
child = child->mNextSibling;
} while (mChild != child);
}
if (nullptr != mEmptyChild) {
nsStyleContext* child = mEmptyChild;
do {
child->List(out, aIndent + 1, aListDescendants);
child = child->mNextSibling;
} while (mEmptyChild != child);
}
}
}
#endif
// Overloaded new operator. Initializes the memory to 0 and relies on an arena
// (which comes from the presShell) to perform the allocation.
void*
nsStyleContext::operator new(size_t sz, nsPresContext* aPresContext)
{
// Check the recycle list first.
return aPresContext->PresShell()->
AllocateByObjectID(eArenaObjectID_nsStyleContext, sz);
}
// Overridden to prevent the global delete from being called, since the memory
// came out of an nsIArena instead of the global delete operator's heap.
void
nsStyleContext::Destroy()
{
// Get the pres context.
RefPtr<nsPresContext> presContext = PresContext();
// Call our destructor.
this->~nsStyleContext();
// Don't let the memory be freed, since it will be recycled
// instead. Don't call the global operator delete.
presContext->PresShell()->
FreeByObjectID(eArenaObjectID_nsStyleContext, this);
}
already_AddRefed<nsStyleContext>
NS_NewStyleContext(nsStyleContext* aParentContext,
nsIAtom* aPseudoTag,
CSSPseudoElementType aPseudoType,
nsRuleNode* aRuleNode,
bool aSkipParentDisplayBasedStyleFixup)
{
RefPtr<nsRuleNode> node = aRuleNode;
RefPtr<nsStyleContext> context =
new (aRuleNode->PresContext())
nsStyleContext(aParentContext, aPseudoTag, aPseudoType, node.forget(),
aSkipParentDisplayBasedStyleFixup);
return context.forget();
}
already_AddRefed<nsStyleContext>
NS_NewStyleContext(nsStyleContext* aParentContext,
nsPresContext* aPresContext,
nsIAtom* aPseudoTag,
CSSPseudoElementType aPseudoType,
already_AddRefed<ServoComputedValues> aComputedValues)
{
RefPtr<nsStyleContext> context =
new (aPresContext)
nsStyleContext(aParentContext, aPresContext, aPseudoTag, aPseudoType,
Move(aComputedValues));
return context.forget();
}
nsIPresShell*
nsStyleContext::Arena()
{
return PresContext()->PresShell();
}
template<typename Func>
static nscolor
GetVisitedDependentColorInternal(nsStyleContext* aSc, Func aColorFunc)
{
nscolor colors[2];
colors[0] = aColorFunc(aSc);
if (nsStyleContext* visitedStyle = aSc->GetStyleIfVisited()) {
colors[1] = aColorFunc(visitedStyle);
return nsStyleContext::
CombineVisitedColors(colors, aSc->RelevantLinkVisited());
}
return colors[0];
}
static nscolor
ExtractColor(nsStyleContext* aContext, const nscolor& aColor)
{
return aColor;
}
static nscolor
ExtractColor(nsStyleContext* aContext, const StyleComplexColor& aColor)
{
return aContext->StyleColor()->CalcComplexColor(aColor);
}
static nscolor
ExtractColor(nsStyleContext* aContext, const nsStyleSVGPaint& aPaintServer)
{
return aPaintServer.Type() == eStyleSVGPaintType_Color
? aPaintServer.GetColor() : NS_RGBA(0, 0, 0, 0);
}
#define STYLE_FIELD(struct_, field_) aField == &struct_::field_ ||
#define STYLE_STRUCT(name_, fields_) \
template<> nscolor \
nsStyleContext::GetVisitedDependentColor( \
decltype(nsStyle##name_::MOZ_ARG_1 fields_) nsStyle##name_::* aField) \
{ \
MOZ_ASSERT(MOZ_FOR_EACH(STYLE_FIELD, (nsStyle##name_,), fields_) false, \
"Getting visited-dependent color for a field in nsStyle"#name_ \
" which is not listed in nsCSSVisitedDependentPropList.h"); \
return GetVisitedDependentColorInternal(this, \
[aField](nsStyleContext* sc) { \
return ExtractColor(sc, sc->Style##name_()->*aField); \
}); \
}
#include "nsCSSVisitedDependentPropList.h"
#undef STYLE_STRUCT
#undef STYLE_FIELD
struct ColorIndexSet {
uint8_t colorIndex, alphaIndex;
};
static const ColorIndexSet gVisitedIndices[2] = { { 0, 0 }, { 1, 0 } };
/* static */ nscolor
nsStyleContext::CombineVisitedColors(nscolor *aColors, bool aLinkIsVisited)
{
if (NS_GET_A(aColors[1]) == 0) {
// If the style-if-visited is transparent, then just use the
// unvisited style rather than using the (meaningless) color
// components of the visited style along with a potentially
// non-transparent alpha value.
aLinkIsVisited = false;
}
// NOTE: We want this code to have as little timing dependence as
// possible on whether this->RelevantLinkVisited() is true.
const ColorIndexSet &set =
gVisitedIndices[aLinkIsVisited ? 1 : 0];
nscolor colorColor = aColors[set.colorIndex];
nscolor alphaColor = aColors[set.alphaIndex];
return NS_RGBA(NS_GET_R(colorColor), NS_GET_G(colorColor),
NS_GET_B(colorColor), NS_GET_A(alphaColor));
}
#ifdef DEBUG
/* static */ const char*
nsStyleContext::StructName(nsStyleStructID aSID)
{
switch (aSID) {
#define STYLE_STRUCT(name_, checkdata_cb) \
case eStyleStruct_##name_: \
return #name_;
#include "nsStyleStructList.h"
#undef STYLE_STRUCT
default:
return "Unknown";
}
}
/* static */ bool
nsStyleContext::LookupStruct(const nsACString& aName, nsStyleStructID& aResult)
{
if (false)
;
#define STYLE_STRUCT(name_, checkdata_cb_) \
else if (aName.EqualsLiteral(#name_)) \
aResult = eStyleStruct_##name_;
#include "nsStyleStructList.h"
#undef STYLE_STRUCT
else
return false;
return true;
}
#endif
void
nsStyleContext::SwapStyleData(nsStyleContext* aNewContext, uint32_t aStructs)
{
static_assert(nsStyleStructID_Length <= 32, "aStructs is not big enough");
for (nsStyleStructID i = nsStyleStructID_Inherited_Start;
i < nsStyleStructID_Inherited_Start + nsStyleStructID_Inherited_Count;
i = nsStyleStructID(i + 1)) {
uint32_t bit = nsCachedStyleData::GetBitForSID(i);
if (!(aStructs & bit)) {
continue;
}
void*& thisData = mCachedInheritedData.mStyleStructs[i];
void*& otherData = aNewContext->mCachedInheritedData.mStyleStructs[i];
if (mBits & bit) {
if (thisData == otherData) {
thisData = nullptr;
}
} else if (!(aNewContext->mBits & bit) && thisData && otherData) {
std::swap(thisData, otherData);
}
}
for (nsStyleStructID i = nsStyleStructID_Reset_Start;
i < nsStyleStructID_Reset_Start + nsStyleStructID_Reset_Count;
i = nsStyleStructID(i + 1)) {
uint32_t bit = nsCachedStyleData::GetBitForSID(i);
if (!(aStructs & bit)) {
continue;
}
if (!mCachedResetData) {
mCachedResetData = new (PresContext()) nsResetStyleData;
}
if (!aNewContext->mCachedResetData) {
aNewContext->mCachedResetData = new (PresContext()) nsResetStyleData;
}
void*& thisData = mCachedResetData->mStyleStructs[i];
void*& otherData = aNewContext->mCachedResetData->mStyleStructs[i];
if (mBits & bit) {
if (thisData == otherData) {
thisData = nullptr;
}
} else if (!(aNewContext->mBits & bit) && thisData && otherData) {
std::swap(thisData, otherData);
}
}
}
void
nsStyleContext::ClearCachedInheritedStyleDataOnDescendants(uint32_t aStructs)
{
if (mChild) {
nsStyleContext* child = mChild;
do {
child->DoClearCachedInheritedStyleDataOnDescendants(aStructs);
child = child->mNextSibling;
} while (mChild != child);
}
if (mEmptyChild) {
nsStyleContext* child = mEmptyChild;
do {
child->DoClearCachedInheritedStyleDataOnDescendants(aStructs);
child = child->mNextSibling;
} while (mEmptyChild != child);
}
}
void
nsStyleContext::DoClearCachedInheritedStyleDataOnDescendants(uint32_t aStructs)
{
NS_ASSERTION(mFrameRefCnt == 0, "frame still referencing style context");
for (nsStyleStructID i = nsStyleStructID_Inherited_Start;
i < nsStyleStructID_Inherited_Start + nsStyleStructID_Inherited_Count;
i = nsStyleStructID(i + 1)) {
uint32_t bit = nsCachedStyleData::GetBitForSID(i);
if (aStructs & bit) {
if (!(mBits & bit) && mCachedInheritedData.mStyleStructs[i]) {
aStructs &= ~bit;
} else {
mCachedInheritedData.mStyleStructs[i] = nullptr;
}
}
}
if (mCachedResetData) {
for (nsStyleStructID i = nsStyleStructID_Reset_Start;
i < nsStyleStructID_Reset_Start + nsStyleStructID_Reset_Count;
i = nsStyleStructID(i + 1)) {
uint32_t bit = nsCachedStyleData::GetBitForSID(i);
if (aStructs & bit) {
if (!(mBits & bit) && mCachedResetData->mStyleStructs[i]) {
aStructs &= ~bit;
} else {
mCachedResetData->mStyleStructs[i] = nullptr;
}
}
}
}
if (aStructs == 0) {
return;
}
ClearCachedInheritedStyleDataOnDescendants(aStructs);
}
void
nsStyleContext::SetIneligibleForSharing()
{
if (mBits & NS_STYLE_INELIGIBLE_FOR_SHARING) {
return;
}
mBits |= NS_STYLE_INELIGIBLE_FOR_SHARING;
if (mChild) {
nsStyleContext* child = mChild;
do {
child->SetIneligibleForSharing();
child = child->mNextSibling;
} while (mChild != child);
}
if (mEmptyChild) {
nsStyleContext* child = mEmptyChild;
do {
child->SetIneligibleForSharing();
child = child->mNextSibling;
} while (mEmptyChild != child);
}
}
#ifdef RESTYLE_LOGGING
nsCString
nsStyleContext::GetCachedStyleDataAsString(uint32_t aStructs)
{
nsCString structs;
for (nsStyleStructID i = nsStyleStructID(0);
i < nsStyleStructID_Length;
i = nsStyleStructID(i + 1)) {
if (aStructs & nsCachedStyleData::GetBitForSID(i)) {
const void* data = GetCachedStyleData(i);
if (!structs.IsEmpty()) {
structs.Append(' ');
}
structs.AppendPrintf("%s=%p", StructName(i), data);
if (HasCachedDependentStyleData(i)) {
structs.AppendLiteral("(dependent)");
} else {
structs.AppendLiteral("(owned)");
}
}
}
return structs;
}
int32_t&
nsStyleContext::LoggingDepth()
{
static int32_t depth = 0;
return depth;
}
void
nsStyleContext::LogStyleContextTree(int32_t aLoggingDepth, uint32_t aStructs)
{
LoggingDepth() = aLoggingDepth;
LogStyleContextTree(true, aStructs);
}
void
nsStyleContext::LogStyleContextTree(bool aFirst, uint32_t aStructs)
{
nsCString structs = GetCachedStyleDataAsString(aStructs);
if (!structs.IsEmpty()) {
structs.Append(' ');
}
nsCString pseudo;
if (mPseudoTag) {
nsAutoString pseudoTag;
mPseudoTag->ToString(pseudoTag);
AppendUTF16toUTF8(pseudoTag, pseudo);
pseudo.Append(' ');
}
nsCString flags;
if (IsStyleIfVisited()) {
flags.AppendLiteral("IS_STYLE_IF_VISITED ");
}
if (HasChildThatUsesGrandancestorStyle()) {
flags.AppendLiteral("CHILD_USES_GRANDANCESTOR_STYLE ");
}
if (IsShared()) {
flags.AppendLiteral("IS_SHARED ");
}
nsCString parent;
if (aFirst) {
parent.AppendPrintf("parent=%p ", mParent.get());
}
LOG_RESTYLE("%p(%d) %s%s%s%s",
this, mRefCnt,
structs.get(), pseudo.get(), flags.get(), parent.get());
LOG_RESTYLE_INDENT();
if (nullptr != mChild) {
nsStyleContext* child = mChild;
do {
child->LogStyleContextTree(false, aStructs);
child = child->mNextSibling;
} while (mChild != child);
}
if (nullptr != mEmptyChild) {
nsStyleContext* child = mEmptyChild;
do {
child->LogStyleContextTree(false, aStructs);
child = child->mNextSibling;
} while (mEmptyChild != child);
}
}
#endif
#ifdef DEBUG
/* static */ void
nsStyleContext::Initialize()
{
Preferences::AddBoolVarCache(
&sExpensiveStyleStructAssertionsEnabled,
"layout.css.expensive-style-struct-assertions.enabled");
}
#endif
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