gecko/layout/style/nsStyleContext.cpp

585 lines
20 KiB
C++

/* -*- 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"
#ifdef DEBUG
// #define NOISY_DEBUG
#endif
//----------------------------------------------------------------------
nsStyleContext::nsStyleContext(nsStyleContext* aParent,
nsIAtom* aPseudoTag,
nsRuleNode* aRuleNode,
nsPresContext* aPresContext)
: mParent(aParent),
mChild(nsnull),
mEmptyChild(nsnull),
mPseudoTag(aPseudoTag),
mRuleNode(aRuleNode),
mBits(0),
mRefCnt(0)
{
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.
if (mCachedStyleData.mResetData || mCachedStyleData.mInheritedData) {
mCachedStyleData.Destroy(mBits, 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)
{
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) {
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::GetStyleData(nsStyleStructID aSID)
{
const void* cachedData = mCachedStyleData.GetStyleData(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.
}
#define STYLE_STRUCT(name_, checkdata_cb_, ctor_args_) \
const nsStyle##name_ * nsStyleContext::GetStyle##name_ () \
{ \
const nsStyle##name_ * cachedData = mCachedStyleData.GetStyle##name_(); \
if (cachedData) \
return cachedData; /* We have computed data stored on this node */ \
/* in the context tree. */ \
/* Else our rule node will take care of it for us. */ \
return mRuleNode->GetStyle##name_(this, PR_TRUE); \
}
#include "nsStyleStructList.h"
#undef STYLE_STRUCT
const void* nsStyleContext::PeekStyleData(nsStyleStructID aSID)
{
const void* cachedData = mCachedStyleData.GetStyleData(aSID);
if (cachedData)
return cachedData; // We have computed data stored on this node in the context tree.
return mRuleNode->GetStyleData(aSID, this, PR_FALSE); // 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)) &&
mCachedStyleData.GetStyleData(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!\n");
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.
const nsCachedStyleData::StyleStructInfo& info =
nsCachedStyleData::gInfo[aSID];
char* resetOrInheritSlot = reinterpret_cast<char*>(&mCachedStyleData) +
info.mCachedStyleDataOffset;
char* resetOrInherit = reinterpret_cast<char*>
(*reinterpret_cast<void**>(resetOrInheritSlot));
if (!resetOrInherit) {
nsPresContext *presContext = mRuleNode->GetPresContext();
if (mCachedStyleData.IsReset(aSID)) {
mCachedStyleData.mResetData = new (presContext) nsResetStyleData;
resetOrInherit = reinterpret_cast<char*>(mCachedStyleData.mResetData);
} else {
mCachedStyleData.mInheritedData =
new (presContext) nsInheritedStyleData;
resetOrInherit =
reinterpret_cast<char*>(mCachedStyleData.mInheritedData);
}
}
char* dataSlot = resetOrInherit + info.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;
nsChangeHint maxHint = nsChangeHint(NS_STYLE_HINT_FRAMECHANGE |
nsChangeHint_UpdateCursor);
#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_ = \
static_cast<const nsStyle##struct_*>( \
PeekStyleData(eStyleStruct_##struct_)); \
if (this##struct_) { \
const nsStyle##struct_* other##struct_ = aOther->GetStyle##struct_(); \
if (compare && \
!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
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);
// 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);
#ifdef MOZ_SVG
maxHint = nsChangeHint(NS_STYLE_HINT_REFLOW | nsChangeHint_UpdateEffects);
DO_STRUCT_DIFFERENCE(SVGReset);
DO_STRUCT_DIFFERENCE(SVG);
#endif
// 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
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.
nsCOMPtr<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,
nsRuleNode* aRuleNode,
nsPresContext* aPresContext)
{
nsStyleContext* context = new (aPresContext) nsStyleContext(aParentContext, aPseudoTag,
aRuleNode, aPresContext);
if (context)
context->AddRef();
return context;
}