content/base/src/nsAttrAndChildArray.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* ***** BEGIN LICENSE BLOCK *****
   3  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   4  *
   5  * The contents of this file are subject to the Mozilla Public License Version
   6  * 1.1 (the "License"); you may not use this file except in compliance with
   7  * the License. You may obtain a copy of the License at
   8  * http://www.mozilla.org/MPL/
   9  *
  10  * Software distributed under the License is distributed on an "AS IS" basis,
  11  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  12  * for the specific language governing rights and limitations under the
  13  * License.
  14  *
  15  * The Original Code is mozilla.org code.
  16  *
  17  * The Initial Developer of the Original Code is
  18  * IBM Corporation.
  19  * Portions created by the Initial Developer are Copyright (C) 2003
  20  * IBM Corporation. All Rights Reserved.
  21  *
  22  * Contributor(s):
  23  *   IBM Corporation
  24  *
  25  * Alternatively, the contents of this file may be used under the terms of
  26  * either the GNU General Public License Version 2 or later (the "GPL"), or
  27  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  28  * in which case the provisions of the GPL or the LGPL are applicable instead
  29  * of those above. If you wish to allow use of your version of this file only
  30  * under the terms of either the GPL or the LGPL, and not to allow others to
  31  * use your version of this file under the terms of the MPL, indicate your
  32  * decision by deleting the provisions above and replace them with the notice
  33  * and other provisions required by the GPL or the LGPL. If you do not delete
  34  * the provisions above, a recipient may use your version of this file under
  35  * the terms of any one of the MPL, the GPL or the LGPL.
  36  *
  37  * ***** END LICENSE BLOCK ***** */
  38
  39 /*
  40  * Storage of the children and attributes of a DOM node; storage for
  41  * the two is unified to minimize footprint.
  42  */
  43
  44 #ifndef nsAttrAndChildArray_h___
  45 #define nsAttrAndChildArray_h___
  46
  47 #include "nscore.h"
  48 #include "nsAttrName.h"
  49 #include "nsAttrValue.h"
  50
  51 class nsINode;
  52 class nsIContent;
  53 class nsMappedAttributes;
  54 class nsHTMLStyleSheet;
  55 class nsRuleWalker;
  56 class nsMappedAttributeElement;
  57
  58 #define ATTRCHILD_ARRAY_GROWSIZE 8
  59 #define ATTRCHILD_ARRAY_LINEAR_THRESHOLD 32
  60
  61 #define ATTRCHILD_ARRAY_ATTR_SLOTS_BITS 10
  62
  63 #define ATTRCHILD_ARRAY_MAX_ATTR_COUNT \
  64     ((1 << ATTRCHILD_ARRAY_ATTR_SLOTS_BITS) - 1)
  65
  66 #define ATTRCHILD_ARRAY_MAX_CHILD_COUNT \
  67     (~PtrBits(0) >> ATTRCHILD_ARRAY_ATTR_SLOTS_BITS)
  68
  69 #define ATTRCHILD_ARRAY_ATTR_SLOTS_COUNT_MASK \
  70     ((1 << ATTRCHILD_ARRAY_ATTR_SLOTS_BITS) - 1)
  71
  72
  73 #define ATTRSIZE (sizeof(InternalAttr) / sizeof(void*))
  74
  75 class nsAttrAndChildArray
  76 {
  77 public:
  78   nsAttrAndChildArray();
  79   ~nsAttrAndChildArray();
  80
  81   PRUint32 ChildCount() const
  82   {
  83     return mImpl ? (mImpl->mAttrAndChildCount >> ATTRCHILD_ARRAY_ATTR_SLOTS_BITS) : 0;
  84   }
  85   nsIContent* ChildAt(PRUint32 aPos) const
  86   {
  87     NS_ASSERTION(aPos < ChildCount(), "out-of-bounds access in nsAttrAndChildArray");
  88     return reinterpret_cast<nsIContent*>(mImpl->mBuffer[AttrSlotsSize() + aPos]);
  89   }
  90   nsIContent* GetSafeChildAt(PRUint32 aPos) const;
  91   nsIContent * const * GetChildArray(PRUint32* aChildCount) const;
  92   nsresult AppendChild(nsIContent* aChild)
  93   {
  94     return InsertChildAt(aChild, ChildCount());
  95   }
  96   nsresult InsertChildAt(nsIContent* aChild, PRUint32 aPos);
  97   void RemoveChildAt(PRUint32 aPos);
  98   PRInt32 IndexOfChild(nsINode* aPossibleChild) const;
  99
 100   PRUint32 AttrCount() const;
 101   const nsAttrValue* GetAttr(nsIAtom* aLocalName, PRInt32 aNamespaceID = kNameSpaceID_None) const;
 102   const nsAttrValue* AttrAt(PRUint32 aPos) const;
 103   nsresult SetAttr(nsIAtom* aLocalName, const nsAString& aValue);
 104   nsresult SetAndTakeAttr(nsIAtom* aLocalName, nsAttrValue& aValue);
 105   nsresult SetAndTakeAttr(nsINodeInfo* aName, nsAttrValue& aValue);
 106
 107   // Remove the attr at position aPos.  The value of the attr is placed in
 108   // aValue; any value that was already in aValue is destroyed.
 109   nsresult RemoveAttrAt(PRUint32 aPos, nsAttrValue& aValue);
 110
 111   // Returns attribute name at given position, *not* out-of-bounds safe
 112   const nsAttrName* AttrNameAt(PRUint32 aPos) const;
 113
 114   // Returns attribute name at given position or null if aPos is out-of-bounds
 115   const nsAttrName* GetSafeAttrNameAt(PRUint32 aPos) const;
 116
 117   // aName is UTF-8 encoded
 118   const nsAttrName* GetExistingAttrNameFromQName(const nsACString& aName) const;
 119   PRInt32 IndexOfAttr(nsIAtom* aLocalName, PRInt32 aNamespaceID = kNameSpaceID_None) const;
 120
 121   nsresult SetAndTakeMappedAttr(nsIAtom* aLocalName, nsAttrValue& aValue,
 122                                 nsMappedAttributeElement* aContent,
 123                                 nsHTMLStyleSheet* aSheet);
 124   nsresult SetMappedAttrStyleSheet(nsHTMLStyleSheet* aSheet);
 125   void WalkMappedAttributeStyleRules(nsRuleWalker* aRuleWalker);
 126
 127   void Compact();
 128
 129 private:
 130   nsAttrAndChildArray(const nsAttrAndChildArray& aOther); // Not to be implemented
 131   nsAttrAndChildArray& operator=(const nsAttrAndChildArray& aOther); // Not to be implemented
 132
 133   void Clear();
 134
 135   PRUint32 NonMappedAttrCount() const;
 136   PRUint32 MappedAttrCount() const;
 137
 138   nsresult GetModifiableMapped(nsMappedAttributeElement* aContent,
 139                                nsHTMLStyleSheet* aSheet,
 140                                PRBool aWillAddAttr,
 141                                nsMappedAttributes** aModifiable);
 142   nsresult MakeMappedUnique(nsMappedAttributes* aAttributes);
 143
 144   PRUint32 AttrSlotsSize() const
 145   {
 146     return AttrSlotCount() * ATTRSIZE;
 147   }
 148
 149   PRUint32 AttrSlotCount() const
 150   {
 151     return mImpl ? mImpl->mAttrAndChildCount & ATTRCHILD_ARRAY_ATTR_SLOTS_COUNT_MASK : 0;
 152   }
 153
 154   void SetChildCount(PRUint32 aCount)
 155   {
 156     mImpl->mAttrAndChildCount =
 157         (mImpl->mAttrAndChildCount & ATTRCHILD_ARRAY_ATTR_SLOTS_COUNT_MASK) |
 158         (aCount << ATTRCHILD_ARRAY_ATTR_SLOTS_BITS);
 159   }
 160
 161   void SetAttrSlotCount(PRUint32 aCount)
 162   {
 163     mImpl->mAttrAndChildCount =
 164         (mImpl->mAttrAndChildCount & ~ATTRCHILD_ARRAY_ATTR_SLOTS_COUNT_MASK) |
 165         aCount;
 166   }
 167
 168   void SetAttrSlotAndChildCount(PRUint32 aSlotCount, PRUint32 aChildCount)
 169   {
 170     mImpl->mAttrAndChildCount = aSlotCount |
 171       (aChildCount << ATTRCHILD_ARRAY_ATTR_SLOTS_BITS);
 172   }
 173
 174   PRBool GrowBy(PRUint32 aGrowSize);
 175   PRBool AddAttrSlot();
 176
 177   struct InternalAttr
 178   {
 179     nsAttrName mName;
 180     nsAttrValue mValue;
 181   };
 182
 183   struct Impl {
 184     PRUint32 mAttrAndChildCount;
 185     PRUint32 mBufferSize;
 186     nsMappedAttributes* mMappedAttrs;
 187     void* mBuffer[1];
 188   };
 189
 190   Impl* mImpl;
 191 };
 192
 193 #endif