gecko-dev/dom/base/nsAttrAndChildArray.h

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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/. */
/*
* Storage of the children and attributes of a DOM node; storage for
* the two is unified to minimize footprint.
*/
#ifndef nsAttrAndChildArray_h___
#define nsAttrAndChildArray_h___
#include "mozilla/Attributes.h"
#include "mozilla/MemoryReporting.h"
#include "mozilla/dom/BorrowedAttrInfo.h"
#include "nscore.h"
#include "nsAttrName.h"
#include "nsAttrValue.h"
#include "nsCaseTreatment.h"
class nsINode;
class nsIContent;
class nsMappedAttributes;
class nsHTMLStyleSheet;
class nsRuleWalker;
class nsMappedAttributeElement;
#define ATTRCHILD_ARRAY_GROWSIZE 8
#define ATTRCHILD_ARRAY_LINEAR_THRESHOLD 32
#define ATTRCHILD_ARRAY_ATTR_SLOTS_BITS 10
#define ATTRCHILD_ARRAY_MAX_ATTR_COUNT \
((1 << ATTRCHILD_ARRAY_ATTR_SLOTS_BITS) - 1)
#define ATTRCHILD_ARRAY_MAX_CHILD_COUNT \
(~uint32_t(0) >> ATTRCHILD_ARRAY_ATTR_SLOTS_BITS)
#define ATTRCHILD_ARRAY_ATTR_SLOTS_COUNT_MASK \
((1 << ATTRCHILD_ARRAY_ATTR_SLOTS_BITS) - 1)
#define ATTRSIZE (sizeof(InternalAttr) / sizeof(void*))
class nsAttrAndChildArray
{
typedef mozilla::dom::BorrowedAttrInfo BorrowedAttrInfo;
public:
nsAttrAndChildArray();
~nsAttrAndChildArray();
uint32_t ChildCount() const
{
return mImpl ? (mImpl->mAttrAndChildCount >> ATTRCHILD_ARRAY_ATTR_SLOTS_BITS) : 0;
}
nsIContent* ChildAt(uint32_t aPos) const
{
NS_ASSERTION(aPos < ChildCount(), "out-of-bounds access in nsAttrAndChildArray");
return reinterpret_cast<nsIContent*>(mImpl->mBuffer[AttrSlotsSize() + aPos]);
}
nsIContent* GetSafeChildAt(uint32_t aPos) const;
nsIContent * const * GetChildArray(uint32_t* aChildCount) const;
nsresult InsertChildAt(nsIContent* aChild, uint32_t aPos);
void RemoveChildAt(uint32_t aPos);
// Like RemoveChildAt but hands the reference to the child being
// removed back to the caller instead of just releasing it.
already_AddRefed<nsIContent> TakeChildAt(uint32_t aPos);
int32_t IndexOfChild(const nsINode* aPossibleChild) const;
bool HasAttrs() const
{
return MappedAttrCount() || (AttrSlotCount() && AttrSlotIsTaken(0));
}
uint32_t AttrCount() const;
const nsAttrValue* GetAttr(nsAtom* aLocalName,
int32_t aNamespaceID = kNameSpaceID_None) const;
// As above but using a string attr name and always using
// kNameSpaceID_None. This is always case-sensitive.
const nsAttrValue* GetAttr(const nsAString& aName) const;
// Get an nsAttrValue by qualified name. Can optionally do
// ASCII-case-insensitive name matching.
const nsAttrValue* GetAttr(const nsAString& aName,
nsCaseTreatment aCaseSensitive) const;
const nsAttrValue* AttrAt(uint32_t aPos) const;
// SetAndSwapAttr swaps the current attribute value with aValue.
// If the attribute was unset, an empty value will be swapped into aValue
// and aHadValue will be set to false. Otherwise, aHadValue will be set to
// true.
nsresult SetAndSwapAttr(nsAtom* aLocalName, nsAttrValue& aValue,
bool* aHadValue);
nsresult SetAndSwapAttr(mozilla::dom::NodeInfo* aName, nsAttrValue& aValue,
bool* aHadValue);
// Remove the attr at position aPos. The value of the attr is placed in
// aValue; any value that was already in aValue is destroyed.
nsresult RemoveAttrAt(uint32_t aPos, nsAttrValue& aValue);
// Returns attribute name at given position, *not* out-of-bounds safe
const nsAttrName* AttrNameAt(uint32_t aPos) const;
// Returns the attribute info at a given position, *not* out-of-bounds safe
BorrowedAttrInfo AttrInfoAt(uint32_t aPos) const;
// Returns attribute name at given position or null if aPos is out-of-bounds
const nsAttrName* GetSafeAttrNameAt(uint32_t aPos) const;
const nsAttrName* GetExistingAttrNameFromQName(const nsAString& aName) const;
int32_t IndexOfAttr(nsAtom* aLocalName, int32_t aNamespaceID = kNameSpaceID_None) const;
// SetAndSwapMappedAttr swaps the current attribute value with aValue.
// If the attribute was unset, an empty value will be swapped into aValue
// and aHadValue will be set to false. Otherwise, aHadValue will be set to
// true.
nsresult SetAndSwapMappedAttr(nsAtom* aLocalName, nsAttrValue& aValue,
nsMappedAttributeElement* aContent,
nsHTMLStyleSheet* aSheet,
bool* aHadValue);
nsresult SetMappedAttrStyleSheet(nsHTMLStyleSheet* aSheet) {
if (!mImpl || !mImpl->mMappedAttrs) {
return NS_OK;
}
return DoSetMappedAttrStyleSheet(aSheet);
}
// Update the rule mapping function on our mapped attributes, if we have any.
// We take a nsMappedAttributeElement, not a nsMapRuleToAttributesFunc,
// because the latter is defined in a header we can't include here.
nsresult UpdateMappedAttrRuleMapper(nsMappedAttributeElement& aElement)
{
if (!mImpl || !mImpl->mMappedAttrs) {
return NS_OK;
}
return DoUpdateMappedAttrRuleMapper(aElement);
}
void Compact();
bool CanFitMoreAttrs() const
{
return AttrSlotCount() < ATTRCHILD_ARRAY_MAX_ATTR_COUNT ||
!AttrSlotIsTaken(ATTRCHILD_ARRAY_MAX_ATTR_COUNT - 1);
}
size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
bool HasMappedAttrs() const
{
return MappedAttrCount();
}
const nsMappedAttributes* GetMapped() const;
// Force this to have mapped attributes, even if those attributes are empty.
nsresult ForceMapped(nsMappedAttributeElement* aContent, nsIDocument* aDocument);
// Clear the servo declaration block on the mapped attributes, if any
// Will assert off main thread
void ClearMappedServoStyle();
// Increases capacity (if necessary) to have enough space to accomodate the
// unmapped attributes and children of |aOther|. If |aAllocateChildren| is not
// true, only enough space for unmapped attributes will be reserved.
// It is REQUIRED that this function be called ONLY when the array is empty.
nsresult EnsureCapacityToClone(const nsAttrAndChildArray& aOther,
bool aAllocateChildren);
private:
nsAttrAndChildArray(const nsAttrAndChildArray& aOther) = delete;
nsAttrAndChildArray& operator=(const nsAttrAndChildArray& aOther) = delete;
void Clear();
uint32_t NonMappedAttrCount() const;
uint32_t MappedAttrCount() const;
// Returns a non-null zero-refcount object.
nsMappedAttributes*
GetModifiableMapped(nsMappedAttributeElement* aContent,
nsHTMLStyleSheet* aSheet,
bool aWillAddAttr,
int32_t aAttrCount = 1);
nsresult MakeMappedUnique(nsMappedAttributes* aAttributes);
uint32_t AttrSlotsSize() const
{
return AttrSlotCount() * ATTRSIZE;
}
uint32_t AttrSlotCount() const
{
return mImpl ? mImpl->mAttrAndChildCount & ATTRCHILD_ARRAY_ATTR_SLOTS_COUNT_MASK : 0;
}
bool AttrSlotIsTaken(uint32_t aSlot) const
{
MOZ_ASSERT(aSlot < AttrSlotCount(), "out-of-bounds");
return mImpl->mBuffer[aSlot * ATTRSIZE];
}
void SetChildCount(uint32_t aCount)
{
mImpl->mAttrAndChildCount =
(mImpl->mAttrAndChildCount & ATTRCHILD_ARRAY_ATTR_SLOTS_COUNT_MASK) |
(aCount << ATTRCHILD_ARRAY_ATTR_SLOTS_BITS);
}
void SetAttrSlotCount(uint32_t aCount)
{
mImpl->mAttrAndChildCount =
(mImpl->mAttrAndChildCount & ~ATTRCHILD_ARRAY_ATTR_SLOTS_COUNT_MASK) |
aCount;
}
void SetAttrSlotAndChildCount(uint32_t aSlotCount, uint32_t aChildCount)
{
mImpl->mAttrAndChildCount = aSlotCount |
(aChildCount << ATTRCHILD_ARRAY_ATTR_SLOTS_BITS);
}
bool GrowBy(uint32_t aGrowSize);
bool AddAttrSlot();
/**
* Set *aPos to aChild and update sibling pointers as needed. aIndex is the
* index at which aChild is actually being inserted. aChildCount is the
* number of kids we had before the insertion.
*/
inline void SetChildAtPos(void** aPos, nsIContent* aChild, uint32_t aIndex,
uint32_t aChildCount);
/**
* Guts of SetMappedAttrStyleSheet for the rare case when we have mapped attrs
*/
nsresult DoSetMappedAttrStyleSheet(nsHTMLStyleSheet* aSheet);
/**
* Guts of UpdateMappedAttrRuleMapper for the case when we have mapped attrs.
*/
nsresult DoUpdateMappedAttrRuleMapper(nsMappedAttributeElement& aElement);
struct InternalAttr
{
nsAttrName mName;
nsAttrValue mValue;
};
struct Impl {
uint32_t mAttrAndChildCount;
uint32_t mBufferSize;
nsMappedAttributes* mMappedAttrs;
void* mBuffer[1];
};
Impl* mImpl;
};
#endif