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pjs/layout/style/nsStyleContext.cpp

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is mozilla.org code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* David Hyatt <hyatt@netscape.com>
* Pierre Phaneuf <pp@ludusdesign.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
/* the interface (to internal code) for retrieving computed style data */
#include "nsStyleConsts.h"
#include "nsString.h"
#include "nsPresContext.h"
#include "nsIStyleRule.h"
#include "nsCOMPtr.h"
#include "nsStyleSet.h"
#include "nsIPresShell.h"
#include "nsRuleNode.h"
#include "nsStyleContext.h"
#include "prlog.h"
#include "nsStyleAnimation.h"
#ifdef DEBUG
// #define NOISY_DEBUG
#endif
//----------------------------------------------------------------------
nsStyleContext::nsStyleContext(nsStyleContext* aParent,
nsIAtom* aPseudoTag,
nsCSSPseudoElements::Type aPseudoType,
nsRuleNode* aRuleNode,
nsPresContext* aPresContext)
: mParent(aParent),
mChild(nsnull),
mEmptyChild(nsnull),
mPseudoTag(aPseudoTag),
mRuleNode(aRuleNode),
mAllocations(nsnull),
mCachedResetData(nsnull),
mBits(((PRUint32)aPseudoType) << NS_STYLE_CONTEXT_TYPE_SHIFT),
mRefCnt(0)
{
PR_STATIC_ASSERT((PR_UINT32_MAX >> NS_STYLE_CONTEXT_TYPE_SHIFT) >
nsCSSPseudoElements::ePseudo_MAX);
mNextSibling = this;
mPrevSibling = this;
if (mParent) {
mParent->AddRef();
mParent->AddChild(this);
#ifdef DEBUG
nsRuleNode *r1 = mParent->GetRuleNode(), *r2 = aRuleNode;
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
}
ApplyStyleFixups(aPresContext);
#define eStyleStruct_LastItem (nsStyleStructID_Length - 1)
NS_ASSERTION(NS_STYLE_INHERIT_MASK & NS_STYLE_INHERIT_BIT(LastItem),
"NS_STYLE_INHERIT_MASK must be bigger, and other bits shifted");
#undef eStyleStruct_LastItem
mRuleNode->AddRef();
}
nsStyleContext::~nsStyleContext()
{
NS_ASSERTION((nsnull == mChild) && (nsnull == mEmptyChild), "destructing context with children");
nsPresContext *presContext = mRuleNode->GetPresContext();
mRuleNode->Release();
presContext->PresShell()->StyleSet()->
NotifyStyleContextDestroyed(presContext, this);
if (mParent) {
mParent->RemoveChild(this);
mParent->Release();
}
// Free up our data structs.
mCachedInheritedData.DestroyStructs(mBits, presContext);
if (mCachedResetData) {
mCachedResetData->Destroy(mBits, presContext);
}
FreeAllocations(presContext);
}
void nsStyleContext::AddChild(nsStyleContext* aChild)
{
NS_ASSERTION(aChild->mPrevSibling == aChild &&
aChild->mNextSibling == aChild,
"child already in a child list");
nsStyleContext **list = aChild->mRuleNode->IsRoot() ? &mEmptyChild : &mChild;
// 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;
}
(*list) = aChild;
}
void nsStyleContext::RemoveChild(nsStyleContext* aChild)
{
NS_PRECONDITION(nsnull != aChild && this == aChild->mParent, "bad argument");
nsStyleContext **list = aChild->mRuleNode->IsRoot() ? &mEmptyChild : &mChild;
if (aChild->mPrevSibling != aChild) { // has siblings
if ((*list) == aChild) {
(*list) = (*list)->mNextSibling;
}
}
else {
NS_ASSERTION((*list) == aChild, "bad sibling pointers");
(*list) = nsnull;
}
aChild->mPrevSibling->mNextSibling = aChild->mNextSibling;
aChild->mNextSibling->mPrevSibling = aChild->mPrevSibling;
aChild->mNextSibling = aChild;
aChild->mPrevSibling = aChild;
}
already_AddRefed<nsStyleContext>
nsStyleContext::FindChildWithRules(const nsIAtom* aPseudoTag,
nsRuleNode* aRuleNode,
nsRuleNode* aRulesIfVisited,
PRBool aRelevantLinkVisited)
{
NS_ABORT_IF_FALSE(aRulesIfVisited || !aRelevantLinkVisited,
"aRelevantLinkVisited should only be set when we have a separate style");
PRUint32 threshold = 10; // The # of siblings we're willing to examine
// before just giving this whole thing up.
nsStyleContext* result = nsnull;
nsStyleContext *list = aRuleNode->IsRoot() ? mEmptyChild : mChild;
if (list) {
nsStyleContext *child = list;
do {
if (child->mRuleNode == aRuleNode &&
child->mPseudoTag == aPseudoTag &&
!child->IsStyleIfVisited() &&
child->RelevantLinkVisited() == aRelevantLinkVisited) {
PRBool match = PR_FALSE;
if (aRulesIfVisited) {
match = child->GetStyleIfVisited() &&
child->GetStyleIfVisited()->mRuleNode == aRulesIfVisited;
} else {
match = !child->GetStyleIfVisited();
}
if (match) {
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);
}
// Add reference for the caller.
result->AddRef();
}
return result;
}
const void* nsStyleContext::GetCachedStyleData(nsStyleStructID aSID)
{
const void* cachedData;
PRBool isReset = nsCachedStyleData::IsReset(aSID);
if (isReset) {
if (mCachedResetData) {
char* slot = reinterpret_cast<char*>(mCachedResetData) +
nsCachedStyleData::gInfo[aSID].mInheritResetOffset;
cachedData = *reinterpret_cast<void**>(slot);
} else {
cachedData = nsnull;
}
} else {
char* slot = reinterpret_cast<char*>(&mCachedInheritedData) +
nsCachedStyleData::gInfo[aSID].mInheritResetOffset;
cachedData = *reinterpret_cast<void**>(slot);
}
return cachedData;
}
const void* nsStyleContext::GetStyleData(nsStyleStructID aSID)
{
const void* cachedData = GetCachedStyleData(aSID);
if (cachedData)
return cachedData; // We have computed data stored on this node in the context tree.
return mRuleNode->GetStyleData(aSID, this, PR_TRUE); // Our rule node will take care of it for us.
}
// 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)
{
// 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 = GetStyleData(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(Display)
UNIQUE_CASE(Background)
UNIQUE_CASE(Text)
UNIQUE_CASE(TextReset)
#undef UNIQUE_CASE
default:
NS_ERROR("Struct type not supported. Please find another way to do this if you can!");
return nsnull;
}
if (!result) {
NS_WARNING("Ran out of memory while trying to allocate memory for a unique style struct! "
"Returning the non-unique data.");
return const_cast<void*>(current);
}
SetStyle(aSID, result);
mBits &= ~nsCachedStyleData::GetBitForSID(aSID);
return result;
}
void
nsStyleContext::SetStyle(nsStyleStructID aSID, void* aStruct)
{
// 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.
char* dataSlot;
if (nsCachedStyleData::IsReset(aSID)) {
if (!mCachedResetData) {
mCachedResetData = new (mRuleNode->GetPresContext()) nsResetStyleData;
// XXXbz And if that fails?
}
dataSlot = reinterpret_cast<char*>(mCachedResetData) +
nsCachedStyleData::gInfo[aSID].mInheritResetOffset;
} else {
dataSlot = reinterpret_cast<char*>(&mCachedInheritedData) +
nsCachedStyleData::gInfo[aSID].mInheritResetOffset;
}
NS_ASSERTION(!*reinterpret_cast<void**>(dataSlot) ||
(mBits & nsCachedStyleData::GetBitForSID(aSID)),
"Going to leak style data");
*reinterpret_cast<void**>(dataSlot) = aStruct;
}
void
nsStyleContext::ApplyStyleFixups(nsPresContext* aPresContext)
{
// 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->HasTextDecorations())
mBits |= NS_STYLE_HAS_TEXT_DECORATIONS;
else {
// We might have defined a decoration.
const nsStyleTextReset* text = GetStyleTextReset();
if (text->mTextDecoration != NS_STYLE_TEXT_DECORATION_NONE &&
text->mTextDecoration != NS_STYLE_TEXT_DECORATION_OVERRIDE_ALL)
mBits |= NS_STYLE_HAS_TEXT_DECORATIONS;
}
if ((mParent && mParent->HasPseudoElementData()) || mPseudoTag) {
mBits |= NS_STYLE_HAS_PSEUDO_ELEMENT_DATA;
}
// Correct tables.
const nsStyleDisplay* disp = GetStyleDisplay();
if (disp->mDisplay == NS_STYLE_DISPLAY_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 = GetStyleText();
if (text->mTextAlign == NS_STYLE_TEXT_ALIGN_MOZ_CENTER ||
text->mTextAlign == NS_STYLE_TEXT_ALIGN_MOZ_RIGHT)
{
nsStyleText* uniqueText = (nsStyleText*)GetUniqueStyleData(eStyleStruct_Text);
uniqueText->mTextAlign = NS_STYLE_TEXT_ALIGN_DEFAULT;
}
}
// 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) {
if (disp->mDisplay != NS_STYLE_DISPLAY_NONE &&
disp->mDisplay != NS_STYLE_DISPLAY_BLOCK &&
disp->mDisplay != NS_STYLE_DISPLAY_TABLE) {
nsStyleDisplay *mutable_display = static_cast<nsStyleDisplay*>
(GetUniqueStyleData(eStyleStruct_Display));
if (mutable_display->mDisplay == NS_STYLE_DISPLAY_INLINE_TABLE)
mutable_display->mDisplay = NS_STYLE_DISPLAY_TABLE;
else
mutable_display->mDisplay = NS_STYLE_DISPLAY_BLOCK;
}
}
// Computer User Interface style, to trigger loads of cursors
GetStyleUserInterface();
}
nsChangeHint
nsStyleContext::CalcStyleDifference(nsStyleContext* aOther)
{
nsChangeHint hint = NS_STYLE_HINT_NONE;
NS_ENSURE_TRUE(aOther, 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.
// If our rule nodes are the same, then we are looking at the same
// style data. We know this because CalcStyleDifference is always
// called on two style contexts that point to the same element, so we
// know that our position in the style context tree is the same and
// our position in the rule node tree is also the same.
PRBool compare = mRuleNode != aOther->mRuleNode;
#define DO_STRUCT_DIFFERENCE(struct_) \
PR_BEGIN_MACRO \
NS_ASSERTION(NS_IsHintSubset(nsStyle##struct_::MaxDifference(), maxHint), \
"Struct placed in the wrong maxHint section"); \
const nsStyle##struct_* this##struct_ = PeekStyle##struct_(); \
if (this##struct_) { \
const nsStyle##struct_* other##struct_ = aOther->GetStyle##struct_(); \
if ((compare || nsStyle##struct_::ForceCompare()) && \
!NS_IsHintSubset(maxHint, hint) && \
this##struct_ != other##struct_) { \
NS_ASSERTION(NS_IsHintSubset( \
this##struct_->CalcDifference(*other##struct_), \
nsStyle##struct_::MaxDifference()), \
"CalcDifference() returned bigger hint than MaxDifference()"); \
NS_UpdateHint(hint, this##struct_->CalcDifference(*other##struct_)); \
} \
} \
PR_END_MACRO
// We begin by examining those style structs that are capable of
// causing the maximal difference, a FRAMECHANGE.
// FRAMECHANGE Structs: Display, XUL, Content, UserInterface,
// Visibility, Outline, TableBorder, Table, Text, UIReset, Quotes
nsChangeHint maxHint = nsChangeHint(NS_STYLE_HINT_FRAMECHANGE |
nsChangeHint_UpdateOpacityLayer);
DO_STRUCT_DIFFERENCE(Display);
maxHint = nsChangeHint(NS_STYLE_HINT_FRAMECHANGE |
nsChangeHint_UpdateCursor);
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);
// If the quotes implementation is ever going to change we might not need
// a framechange here and a reflow should be sufficient. See bug 35768.
DO_STRUCT_DIFFERENCE(Quotes);
maxHint = nsChangeHint(NS_STYLE_HINT_REFLOW | nsChangeHint_UpdateEffects);
DO_STRUCT_DIFFERENCE(SVGReset);
DO_STRUCT_DIFFERENCE(SVG);
// At this point, we know that the worst kind of damage we could do is
// a reflow.
maxHint = NS_STYLE_HINT_REFLOW;
// The following structs cause (as their maximal difference) a reflow
// to occur. REFLOW Structs: Font, Margin, Padding, Border, List,
// Position, Text, TextReset
DO_STRUCT_DIFFERENCE(Font);
DO_STRUCT_DIFFERENCE(Margin);
DO_STRUCT_DIFFERENCE(Padding);
DO_STRUCT_DIFFERENCE(Border);
DO_STRUCT_DIFFERENCE(Position);
DO_STRUCT_DIFFERENCE(TextReset);
// At this point, we know that the worst kind of damage we could do is
// a re-render (i.e., a VISUAL change).
maxHint = NS_STYLE_HINT_VISUAL;
// The following structs cause (as their maximal difference) a
// re-render to occur. VISUAL Structs: Color, Background
DO_STRUCT_DIFFERENCE(Color);
DO_STRUCT_DIFFERENCE(Background);
#undef DO_STRUCT_DIFFERENCE
// Note that we do not check whether this->RelevantLinkVisited() !=
// aOther->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 = aOther->GetStyleIfVisited();
if (!thisVis != !otherVis) {
// One style context has a style-if-visited and the other doesn't.
// Presume a difference.
NS_UpdateHint(hint, nsChangeHint_RepaintFrame);
} else if (thisVis && !NS_IsHintSubset(nsChangeHint_RepaintFrame, hint)) {
// Both style contexts have a style-if-visited.
PRBool change = PR_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.
if (PeekStyleColor()) {
if (thisVis->GetStyleColor()->mColor !=
otherVis->GetStyleColor()->mColor) {
change = PR_TRUE;
}
}
// NB: Calling Peek on |this|, not |thisVis| (see above).
if (!change && PeekStyleBackground()) {
if (thisVis->GetStyleBackground()->mBackgroundColor !=
otherVis->GetStyleBackground()->mBackgroundColor) {
change = PR_TRUE;
}
}
// NB: Calling Peek on |this|, not |thisVis| (see above).
if (!change && PeekStyleBorder()) {
const nsStyleBorder *thisVisBorder = thisVis->GetStyleBorder();
const nsStyleBorder *otherVisBorder = otherVis->GetStyleBorder();
NS_FOR_CSS_SIDES(side) {
PRBool thisFG, otherFG;
nscolor thisColor, otherColor;
thisVisBorder->GetBorderColor(side, thisColor, thisFG);
otherVisBorder->GetBorderColor(side, otherColor, otherFG);
if (thisFG != otherFG || (!thisFG && thisColor != otherColor)) {
change = PR_TRUE;
break;
}
}
}
// NB: Calling Peek on |this|, not |thisVis| (see above).
if (!change && PeekStyleOutline()) {
const nsStyleOutline *thisVisOutline = thisVis->GetStyleOutline();
const nsStyleOutline *otherVisOutline = otherVis->GetStyleOutline();
PRBool haveColor;
nscolor thisColor, otherColor;
if (thisVisOutline->GetOutlineInitialColor() !=
otherVisOutline->GetOutlineInitialColor() ||
(haveColor = thisVisOutline->GetOutlineColor(thisColor)) !=
otherVisOutline->GetOutlineColor(otherColor) ||
(haveColor && thisColor != otherColor)) {
change = PR_TRUE;
}
}
// NB: Calling Peek on |this|, not |thisVis| (see above).
if (!change && PeekStyleColumn()) {
const nsStyleColumn *thisVisColumn = thisVis->GetStyleColumn();
const nsStyleColumn *otherVisColumn = otherVis->GetStyleColumn();
if (thisVisColumn->mColumnRuleColor != otherVisColumn->mColumnRuleColor ||
thisVisColumn->mColumnRuleColorIsForeground !=
otherVisColumn->mColumnRuleColorIsForeground) {
change = PR_TRUE;
}
}
// NB: Calling Peek on |this|, not |thisVis| (see above).
if (!change && PeekStyleSVG()) {
const nsStyleSVG *thisVisSVG = thisVis->GetStyleSVG();
const nsStyleSVG *otherVisSVG = otherVis->GetStyleSVG();
if (thisVisSVG->mFill != otherVisSVG->mFill ||
thisVisSVG->mStroke != otherVisSVG->mStroke) {
change = PR_TRUE;
}
}
if (change) {
NS_UpdateHint(hint, nsChangeHint_RepaintFrame);
}
}
return hint;
}
void
nsStyleContext::Mark()
{
// Mark our rule node.
mRuleNode->Mark();
// Mark our children (i.e., tell them to mark their rule nodes, etc.).
if (mChild) {
nsStyleContext* child = mChild;
do {
child->Mark();
child = child->mNextSibling;
} while (mChild != child);
}
if (mEmptyChild) {
nsStyleContext* child = mEmptyChild;
do {
child->Mark();
child = child->mNextSibling;
} while (mEmptyChild != child);
}
}
#ifdef DEBUG
void nsStyleContext::List(FILE* out, PRInt32 aIndent)
{
// Indent
PRInt32 ix;
for (ix = aIndent; --ix >= 0; ) fputs(" ", out);
fprintf(out, "%p(%d) parent=%p ",
(void*)this, mRefCnt, (void *)mParent);
if (mPseudoTag) {
nsAutoString buffer;
mPseudoTag->ToString(buffer);
fputs(NS_LossyConvertUTF16toASCII(buffer).get(), out);
fputs(" ", out);
}
if (mRuleNode) {
fputs("{\n", out);
nsRuleNode* ruleNode = mRuleNode;
while (ruleNode) {
nsIStyleRule *styleRule = ruleNode->GetRule();
if (styleRule) {
styleRule->List(out, aIndent + 1);
}
ruleNode = ruleNode->GetParent();
}
for (ix = aIndent; --ix >= 0; ) fputs(" ", out);
fputs("}\n", out);
}
else {
fputs("{}\n", out);
}
if (nsnull != mChild) {
nsStyleContext* child = mChild;
do {
child->List(out, aIndent + 1);
child = child->mNextSibling;
} while (mChild != child);
}
if (nsnull != mEmptyChild) {
nsStyleContext* child = mEmptyChild;
do {
child->List(out, aIndent + 1);
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) CPP_THROW_NEW
{
// Check the recycle list first.
return aPresContext->AllocateFromShell(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 from our rule node.
nsRefPtr<nsPresContext> presContext = mRuleNode->GetPresContext();
// 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->FreeToShell(sizeof(nsStyleContext), this);
}
already_AddRefed<nsStyleContext>
NS_NewStyleContext(nsStyleContext* aParentContext,
nsIAtom* aPseudoTag,
nsCSSPseudoElements::Type aPseudoType,
nsRuleNode* aRuleNode,
nsPresContext* aPresContext)
{
nsStyleContext* context =
new (aPresContext) nsStyleContext(aParentContext, aPseudoTag, aPseudoType,
aRuleNode, aPresContext);
if (context)
context->AddRef();
return context;
}
static nscolor ExtractColor(nsCSSProperty aProperty,
nsStyleContext *aStyleContext)
{
nsStyleAnimation::Value val;
#ifdef DEBUG
PRBool success =
#endif
nsStyleAnimation::ExtractComputedValue(aProperty, aStyleContext, val);
NS_ABORT_IF_FALSE(success,
"aProperty must be extractable by nsStyleAnimation");
return val.GetColorValue();
}
struct ColorIndexSet {
PRUint8 colorIndex, alphaIndex;
};
static const ColorIndexSet gVisitedIndices[2] = { { 0, 0 }, { 1, 0 } };
nscolor
nsStyleContext::GetVisitedDependentColor(nsCSSProperty aProperty)
{
NS_ASSERTION(aProperty == eCSSProperty_color ||
aProperty == eCSSProperty_background_color ||
aProperty == eCSSProperty_border_top_color ||
aProperty == eCSSProperty_border_right_color_value ||
aProperty == eCSSProperty_border_bottom_color ||
aProperty == eCSSProperty_border_left_color_value ||
aProperty == eCSSProperty_outline_color ||
aProperty == eCSSProperty__moz_column_rule_color ||
aProperty == eCSSProperty_fill ||
aProperty == eCSSProperty_stroke,
"we need to add to nsStyleContext::CalcStyleDifference");
nscolor colors[2];
colors[0] = ExtractColor(aProperty, this);
nsStyleContext *visitedStyle = this->GetStyleIfVisited();
if (!visitedStyle) {
return colors[0];
}
colors[1] = ExtractColor(aProperty, visitedStyle);
return nsStyleContext::CombineVisitedColors(colors,
this->RelevantLinkVisited());
}
/* static */ nscolor
nsStyleContext::CombineVisitedColors(nscolor *aColors, PRBool 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 = PR_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));
}
void*
nsStyleContext::Alloc(size_t aSize)
{
nsIPresShell *shell = PresContext()->PresShell();
aSize += offsetof(AllocationHeader, mStorageStart);
AllocationHeader *alloc =
static_cast<AllocationHeader*>(shell->AllocateMisc(aSize));
alloc->mSize = aSize; // NOTE: inflated by header
alloc->mNext = mAllocations;
mAllocations = alloc;
return static_cast<void*>(&alloc->mStorageStart);
}
void
nsStyleContext::FreeAllocations(nsPresContext *aPresContext)
{
nsIPresShell *shell = aPresContext->PresShell();
for (AllocationHeader *alloc = mAllocations, *next; alloc; alloc = next) {
next = alloc->mNext;
shell->FreeMisc(alloc->mSize, alloc);
}
}
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