The Tor Browser / file revision

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

 /* 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 "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

 {

 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 AppendChild(nsIContent* aChild)

   {

     return InsertChildAt(aChild, ChildCount());

   }

   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(nsIAtom* 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;

   nsresult SetAndTakeAttr(nsIAtom* aLocalName, nsAttrValue& aValue);

   nsresult SetAndTakeAttr(nsINodeInfo* aName, nsAttrValue& aValue);

   // 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 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(nsIAtom* aLocalName, int32_t aNamespaceID = kNameSpaceID_None) const;

   nsresult SetAndTakeMappedAttr(nsIAtom* aLocalName, nsAttrValue& aValue,

                                 nsMappedAttributeElement* aContent,

                                 nsHTMLStyleSheet* aSheet);

   nsresult SetMappedAttrStyleSheet(nsHTMLStyleSheet* aSheet) {

     if (!mImpl || !mImpl->mMappedAttrs) {

       return NS_OK;

     }

     return DoSetMappedAttrStyleSheet(aSheet);

   }

   void WalkMappedAttributeStyleRules(nsRuleWalker* aRuleWalker);

   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();

   }

 private:

   nsAttrAndChildArray(const nsAttrAndChildArray& aOther) MOZ_DELETE;

   nsAttrAndChildArray& operator=(const nsAttrAndChildArray& aOther) MOZ_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);

   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

   {

     NS_PRECONDITION(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);

   struct InternalAttr

   {

     nsAttrName mName;

     nsAttrValue mValue;

   };

   struct Impl {

     uint32_t mAttrAndChildCount;

     uint32_t mBufferSize;

     nsMappedAttributes* mMappedAttrs;

     void* mBuffer[1];

   };

   Impl* mImpl;

 };

 #endif