gecko-dev/dom/base/nsIdentifierMapEntry.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/. */
/*
* Base class for all our document implementations.
*/
#ifndef nsIdentifierMapEntry_h
#define nsIdentifierMapEntry_h
#include "PLDHashTable.h"
#include "mozilla/MemoryReporting.h"
#include "mozilla/Move.h"
#include "mozilla/net/ReferrerPolicy.h"
#include "nsCOMPtr.h"
#include "nsAtom.h"
#include "nsTArray.h"
#include "nsTHashtable.h"
class nsIContent;
class nsContentList;
class nsBaseContentList;
/**
* Right now our identifier map entries contain information for 'name'
* and 'id' mappings of a given string. This is so that
* nsHTMLDocument::ResolveName only has to do one hash lookup instead
* of two. It's not clear whether this still matters for performance.
*
* We also store the document.all result list here. This is mainly so that
* when all elements with the given ID are removed and we remove
* the ID's nsIdentifierMapEntry, the document.all result is released too.
* Perhaps the document.all results should have their own hashtable
* in nsHTMLDocument.
*/
class nsIdentifierMapEntry : public PLDHashEntryHdr
{
typedef mozilla::dom::Element Element;
typedef mozilla::net::ReferrerPolicy ReferrerPolicy;
/**
* @see nsIDocument::IDTargetObserver, this is just here to avoid include
* hell.
*/
typedef bool (* IDTargetObserver)(Element* aOldElement,
Element* aNewelement, void* aData);
public:
struct AtomOrString
{
MOZ_IMPLICIT AtomOrString(nsAtom* aAtom) : mAtom(aAtom) {}
MOZ_IMPLICIT AtomOrString(const nsAString& aString) : mString(aString) {}
AtomOrString(const AtomOrString& aOther)
: mAtom(aOther.mAtom)
, mString(aOther.mString)
{
}
AtomOrString(AtomOrString&& aOther)
: mAtom(aOther.mAtom.forget())
, mString(aOther.mString)
{
}
RefPtr<nsAtom> mAtom;
const nsString mString;
};
typedef const AtomOrString& KeyType;
typedef const AtomOrString* KeyTypePointer;
explicit nsIdentifierMapEntry(const AtomOrString& aKey);
explicit nsIdentifierMapEntry(const AtomOrString* aKey);
nsIdentifierMapEntry(nsIdentifierMapEntry&& aOther);
~nsIdentifierMapEntry();
nsString GetKeyAsString() const
{
if (mKey.mAtom) {
return nsAtomString(mKey.mAtom);
}
return mKey.mString;
}
bool KeyEquals(const KeyTypePointer aOtherKey) const
{
if (mKey.mAtom) {
if (aOtherKey->mAtom) {
return mKey.mAtom == aOtherKey->mAtom;
}
return mKey.mAtom->Equals(aOtherKey->mString);
}
if (aOtherKey->mAtom) {
return aOtherKey->mAtom->Equals(mKey.mString);
}
return mKey.mString.Equals(aOtherKey->mString);
}
static KeyTypePointer KeyToPointer(KeyType aKey) { return &aKey; }
static PLDHashNumber HashKey(const KeyTypePointer aKey)
{
return aKey->mAtom ?
aKey->mAtom->hash() : mozilla::HashString(aKey->mString);
}
enum { ALLOW_MEMMOVE = false };
void AddNameElement(nsINode* aDocument, Element* aElement);
void RemoveNameElement(Element* aElement);
bool IsEmpty();
nsBaseContentList* GetNameContentList() {
return mNameContentList;
}
bool HasNameElement() const;
/**
* Returns the element if we know the element associated with this
* id. Otherwise returns null.
*/
Element* GetIdElement();
/**
* Returns the list of all elements associated with this id.
*/
const nsTArray<Element*>& GetIdElements() const {
return mIdContentList;
}
/**
* If this entry has a non-null image element set (using SetImageElement),
* the image element will be returned, otherwise the same as GetIdElement().
*/
Element* GetImageIdElement();
/**
* This can fire ID change callbacks.
* @return true if the content could be added, false if we failed due
* to OOM.
*/
bool AddIdElement(Element* aElement);
/**
* This can fire ID change callbacks.
*/
void RemoveIdElement(Element* aElement);
/**
* Set the image element override for this ID. This will be returned by
* GetIdElement(true) if non-null.
*/
void SetImageElement(Element* aElement);
bool HasIdElementExposedAsHTMLDocumentProperty();
bool HasContentChangeCallback() { return mChangeCallbacks != nullptr; }
void AddContentChangeCallback(IDTargetObserver aCallback,
void* aData, bool aForImage);
void RemoveContentChangeCallback(IDTargetObserver aCallback,
void* aData, bool aForImage);
void Traverse(nsCycleCollectionTraversalCallback* aCallback);
struct ChangeCallback {
IDTargetObserver mCallback;
void* mData;
bool mForImage;
};
struct ChangeCallbackEntry : public PLDHashEntryHdr {
typedef const ChangeCallback KeyType;
typedef const ChangeCallback* KeyTypePointer;
explicit ChangeCallbackEntry(const ChangeCallback* aKey) :
mKey(*aKey) { }
ChangeCallbackEntry(const ChangeCallbackEntry& toCopy) :
mKey(toCopy.mKey) { }
KeyType GetKey() const { return mKey; }
bool KeyEquals(KeyTypePointer aKey) const {
return aKey->mCallback == mKey.mCallback &&
aKey->mData == mKey.mData &&
aKey->mForImage == mKey.mForImage;
}
static KeyTypePointer KeyToPointer(KeyType& aKey) { return &aKey; }
static PLDHashNumber HashKey(KeyTypePointer aKey)
{
return mozilla::HashGeneric(aKey->mCallback, aKey->mData);
}
enum { ALLOW_MEMMOVE = true };
ChangeCallback mKey;
};
size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
private:
nsIdentifierMapEntry(const nsIdentifierMapEntry& aOther) = delete;
nsIdentifierMapEntry& operator=(const nsIdentifierMapEntry& aOther) = delete;
void FireChangeCallbacks(Element* aOldElement, Element* aNewElement,
bool aImageOnly = false);
AtomOrString mKey;
// empty if there are no elements with this ID.
// The elements are stored as weak pointers.
AutoTArray<Element*, 1> mIdContentList;
RefPtr<nsBaseContentList> mNameContentList;
nsAutoPtr<nsTHashtable<ChangeCallbackEntry> > mChangeCallbacks;
RefPtr<Element> mImageElement;
};
#endif // #ifndef nsIdentifierMapEntry_h