gecko-dev/layout/style/nsStyleContext.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 "nsStyleContext.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/GeckoStyleContext.h"
#include "mozilla/ServoStyleContext.h"
#include "nsStyleContextInlines.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
};
#endif
nsStyleContext::nsStyleContext(nsAtom* aPseudoTag,
CSSPseudoElementType aPseudoType)
: mPseudoTag(aPseudoTag)
, mBits(((uint64_t)aPseudoType) << NS_STYLE_CONTEXT_TYPE_SHIFT)
{
// 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
#ifdef DEBUG
static_assert(MOZ_ARRAY_LENGTH(nsStyleContext::sDependencyTable)
== nsStyleStructID_Length,
"Number of items in dependency table doesn't match IDs");
#endif
}
nsChangeHint
nsStyleContext::CalcStyleDifference(nsStyleContext* aNewContext,
uint32_t* aEqualStructs,
uint32_t* aSamePointerStructs,
bool aIgnoreVariables)
{
AUTO_PROFILER_LABEL("nsStyleContext::CalcStyleDifference", CSS);
static_assert(nsStyleStructID_Length <= 32,
"aEqualStructs is not big enough");
MOZ_ASSERT(!aIgnoreVariables || IsServo(),
"aIgnoreVariables must be false for Gecko contexts");
*aEqualStructs = 0;
*aSamePointerStructs = 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;
if (IsGecko()) {
// CalcStyleDifference is always called on the main thread for Gecko
// style contexts. This assertion helps the heap write static analysis.
MOZ_ASSERT(NS_IsMainThread());
// 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 == otherVariables) {
*aSamePointerStructs |= NS_STYLE_INHERIT_BIT(Variables);
*aEqualStructs |= NS_STYLE_INHERIT_BIT(Variables);
} else if (thisVariables->mVariables == otherVariables->mVariables) {
*aEqualStructs |= NS_STYLE_INHERIT_BIT(Variables);
}
} else {
*aEqualStructs |= NS_STYLE_INHERIT_BIT(Variables);
}
} else {
if (aIgnoreVariables ||
Servo_ComputedValues_EqualCustomProperties(
AsServo()->ComputedData(),
aNewContext->ComputedData())) {
*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 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.
//
// For Gecko structs, we just defer to PeekStyleXXX. But for Servo structs,
// we need to use the aRelevantStructs bitfield passed in to determine
// whether to return a struct or not, since this->mBits might not yet
// be correct (due to not calling ResolveSameStructsAs on it yet).
#define PEEK(struct_) \
(IsGecko() \
? PeekStyle##struct_() \
: AsServo()->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_LIST_IGNORE_VARIABLES
#define STYLE_STRUCT(name_, callback_) \
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
#undef STYLE_STRUCT_LIST_IGNORE_VARIABLES
#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_LIST_IGNORE_VARIABLES
#define STYLE_STRUCT(name_, callback_) \
{ \
const nsStyle##name_* data = PEEK(name_); \
if (!data || data == aNewContext->ThreadsafeStyle##name_()) { \
*aSamePointerStructs |= NS_STYLE_INHERIT_BIT(name_); \
} \
}
#include "nsStyleStructList.h"
#undef STYLE_STRUCT_LIST_IGNORE_VARIABLES
#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();
nsStyleContext* 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)) {
// 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 && (PEEK(name_) != nullptr)) { \
const nsStyle##name_* thisVisStruct = \
thisVis->ThreadsafeStyle##name_(); \
const nsStyle##name_* otherVisStruct = \
otherVis->ThreadsafeStyle##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;
}
namespace mozilla {
void
GeckoStyleContext::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
}
} // namespace mozilla
#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, IsGecko() ? AsGecko()->mRefCnt : 0,
IsGecko() ? AsGecko()->GetParent() : nullptr));
if (mPseudoTag) {
nsAutoString buffer;
mPseudoTag->ToString(buffer);
AppendUTF16toUTF8(buffer, str);
str.Append(' ');
}
if (IsServo()) {
fprintf_stderr(out, "%s{ServoComputedData}\n", str.get());
} else if (nsRuleNode* ruleNode = AsGecko()->RuleNode()) {
fprintf_stderr(out, "%s{\n", str.get());
str.Truncate();
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 (GeckoStyleContext* gecko = GetAsGecko()) {
gecko->ListDescendants(out, aIndent);
}
}
}
#endif
already_AddRefed<GeckoStyleContext>
NS_NewStyleContext(GeckoStyleContext* aParentContext,
nsAtom* aPseudoTag,
CSSPseudoElementType aPseudoType,
nsRuleNode* aRuleNode,
bool aSkipParentDisplayBasedStyleFixup)
{
RefPtr<nsRuleNode> node = aRuleNode;
RefPtr<GeckoStyleContext> context =
new (aRuleNode->PresContext())
GeckoStyleContext(aParentContext, aPseudoTag, aPseudoType, node.forget(),
aSkipParentDisplayBasedStyleFixup);
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;
}
void
nsStyleContext::FrameAddRef()
{
if (auto gecko = GetAsGecko()) {
gecko->FrameAddRef();
}
}
void
nsStyleContext::FrameRelease()
{
if (auto gecko = GetAsGecko()) {
gecko->FrameRelease();
}
}
#endif