gecko-dev/layout/style/ComputedStyle.cpp

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/* -*- 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/. */
/* the interface (to internal code) for retrieving computed style data */
#include "mozilla/ComputedStyle.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 "nsWindowSizes.h"
#include "nsCOMPtr.h"
#include "nsIPresShell.h"
#include "GeckoProfiler.h"
#include "nsIDocument.h"
#include "nsPrintfCString.h"
#include "RubyUtils.h"
#include "mozilla/ArenaObjectID.h"
#include "mozilla/ComputedStyleInlines.h"
#include "mozilla/Preferences.h"
#include "mozilla/ReflowInput.h"
#include "nsLayoutUtils.h"
#include "nsCoord.h"
// Ensure the binding function declarations in ComputedStyle.h matches
// those in ServoBindings.h.
#include "mozilla/ServoBindings.h"
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) eDebugStyleStruct_##name,
#include "nsStyleStructList.h"
#undef STYLE_STRUCT
};
#define STYLE_STRUCT(name) \
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
#endif
ComputedStyle::ComputedStyle(nsPresContext* aPresContext,
nsAtom* aPseudoTag,
CSSPseudoElementType aPseudoType,
ServoComputedDataForgotten aComputedValues)
: mPresContext(aPresContext)
, mSource(aComputedValues)
, mPseudoTag(aPseudoTag)
, mBits(((uint64_t)aPseudoType) << NS_STYLE_CONTEXT_TYPE_SHIFT)
{
AddStyleBit(Servo_ComputedValues_GetStyleBits(this));
MOZ_ASSERT(ComputedData());
// 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");
#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
}
nsChangeHint
ComputedStyle::CalcStyleDifference(ComputedStyle* aNewContext,
uint32_t* aEqualStructs)
{
AUTO_PROFILER_LABEL("ComputedStyle::CalcStyleDifference", 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;
DebugOnly<int> styleStructCount = 0;
// 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 could avoid to accumulate any change
// hints for those structs.
//
// FIXME(emilio): Reintroduce that optimization either for all kind of structs
// after bug 1368290 with a weak parent pointer from text, or just for reset
// structs.
#define PEEK(struct_) \
ComputedData()->GetStyle##struct_()
#define EXPAND(...) __VA_ARGS__
#define DO_STRUCT_DIFFERENCE_WITH_ARGS(struct_, extra_args_) \
PR_BEGIN_MACRO \
const nsStyle##struct_* this##struct_ = PEEK(struct_); \
if (this##struct_) { \
structsFound |= NS_STYLE_INHERIT_BIT(struct_); \
\
const nsStyle##struct_* other##struct_ = \
aNewContext->ThreadsafeStyle##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_ EXPAND extra_args_); \
hint |= difference; \
if (!difference) { \
*aEqualStructs |= NS_STYLE_INHERIT_BIT(struct_); \
} \
} \
} else { \
*aEqualStructs |= NS_STYLE_INHERIT_BIT(struct_); \
} \
styleStructCount++; \
PR_END_MACRO
#define DO_STRUCT_DIFFERENCE(struct_) \
DO_STRUCT_DIFFERENCE_WITH_ARGS(struct_, ())
// 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".
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_WITH_ARGS(List, (, PEEK(Display)));
DO_STRUCT_DIFFERENCE(SVGReset);
DO_STRUCT_DIFFERENCE(SVG);
DO_STRUCT_DIFFERENCE_WITH_ARGS(Position, (, PEEK(Visibility)));
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 DO_STRUCT_DIFFERENCE
#undef DO_STRUCT_DIFFERENCE_WITH_ARGS
#undef EXPAND
MOZ_ASSERT(styleStructCount == nsStyleStructID_Length,
"missing a call to DO_STRUCT_DIFFERENCE");
#ifdef DEBUG
#define STYLE_STRUCT(name_) \
MOZ_ASSERT(!!(structsFound & NS_STYLE_INHERIT_BIT(name_)) == \
(PEEK(name_) != nullptr), \
"PeekStyleData results must not change in the middle of " \
"difference calculation.");
#include "nsStyleStructList.h"
#undef STYLE_STRUCT
#endif
// 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.
ComputedStyle* thisVis = GetStyleIfVisited();
ComputedStyle* otherVis = aNewContext->GetStyleIfVisited();
if (!thisVis != !otherVis) {
// One style has a style-if-visited and the other doesn't.
// Presume a difference.
#define STYLE_STRUCT(name_, fields_) \
*aEqualStructs &= ~NS_STYLE_INHERIT_BIT(name_);
#include "nsCSSVisitedDependentPropList.h"
#undef STYLE_STRUCT
hint |= nsChangeHint_RepaintFrame;
} else if (thisVis) {
// Both styles 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 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 (PEEK(name_)) { \
const nsStyle##name_* thisVisStruct = \
thisVis->ThreadsafeStyle##name_(); \
const nsStyle##name_* otherVisStruct = \
otherVis->ThreadsafeStyle##name_(); \
if (MOZ_FOR_EACH_SEPARATED(STYLE_FIELD, (||), (), fields_)) { \
*aEqualStructs &= ~NS_STYLE_INHERIT_BIT(name_); \
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;
}
#ifdef DEBUG
void ComputedStyle::List(FILE* out, int32_t aIndent)
{
nsAutoCString str;
// Indent
int32_t ix;
for (ix = aIndent; --ix >= 0; ) {
str.AppendLiteral(" ");
}
str.Append(nsPrintfCString("%p(%d) parent=%p ",
(void*)this,
0, nullptr
));
if (mPseudoTag) {
nsAutoString buffer;
mPseudoTag->ToString(buffer);
AppendUTF16toUTF8(buffer, str);
str.Append(' ');
}
fprintf_stderr(out, "%s{ServoComputedData}\n", str.get());
}
#endif
nsIPresShell*
ComputedStyle::Arena()
{
return mPresContext->PresShell();
}
template<typename Func>
static nscolor
GetVisitedDependentColorInternal(ComputedStyle* aSc, Func aColorFunc)
{
nscolor colors[2];
colors[0] = aColorFunc(aSc);
if (ComputedStyle* visitedStyle = aSc->GetStyleIfVisited()) {
colors[1] = aColorFunc(visitedStyle);
return ComputedStyle::
CombineVisitedColors(colors, aSc->RelevantLinkVisited());
}
return colors[0];
}
static nscolor
ExtractColor(ComputedStyle* aStyle, const nscolor& aColor)
{
return aColor;
}
static nscolor
ExtractColor(ComputedStyle* aStyle, const StyleComplexColor& aColor)
{
return aColor.CalcColor(aStyle);
}
static nscolor
ExtractColor(ComputedStyle* aStyle, 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 \
ComputedStyle::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](ComputedStyle* 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
ComputedStyle::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*
ComputedStyle::StructName(nsStyleStructID aSID)
{
switch (aSID) {
#define STYLE_STRUCT(name_) \
case eStyleStruct_##name_: \
return #name_;
#include "nsStyleStructList.h"
#undef STYLE_STRUCT
default:
return "Unknown";
}
}
/* static */ bool
ComputedStyle::LookupStruct(const nsACString& aName, nsStyleStructID& aResult)
{
if (false)
;
#define STYLE_STRUCT(name_) \
else if (aName.EqualsLiteral(#name_)) \
aResult = eStyleStruct_##name_;
#include "nsStyleStructList.h"
#undef STYLE_STRUCT
else
return false;
return true;
}
#endif // DEBUG
ComputedStyle*
ComputedStyle::GetCachedLazyPseudoStyle(CSSPseudoElementType aPseudo) const
{
MOZ_ASSERT(aPseudo != CSSPseudoElementType::NotPseudo &&
aPseudo != CSSPseudoElementType::InheritingAnonBox &&
aPseudo != CSSPseudoElementType::NonInheritingAnonBox);
MOZ_ASSERT(!IsLazilyCascadedPseudoElement(), "Lazy pseudos can't inherit lazy pseudos");
if (nsCSSPseudoElements::PseudoElementSupportsUserActionState(aPseudo)) {
return nullptr;
}
return mCachedInheritingStyles.Lookup(nsCSSPseudoElements::GetPseudoAtom(aPseudo));
}
MOZ_DEFINE_MALLOC_ENCLOSING_SIZE_OF(ServoComputedValuesMallocEnclosingSizeOf)
void
ComputedStyle::AddSizeOfIncludingThis(nsWindowSizes& aSizes,
size_t* aCVsSize) const
{
// Note: |this| sits within a servo_arc::Arc, i.e. it is preceded by a
// refcount. So we need to measure it with a function that can handle an
// interior pointer. We use ServoComputedValuesMallocEnclosingSizeOf to
// clearly identify in DMD's output the memory measured here.
*aCVsSize += ServoComputedValuesMallocEnclosingSizeOf(this);
mSource.AddSizeOfExcludingThis(aSizes);
mCachedInheritingStyles.AddSizeOfIncludingThis(aSizes, aCVsSize);
}
} // namespace mozilla