dom/base/nsMappedAttributes.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 /*
   8  * A unique per-element set of attributes that is used as an
   9  * nsIStyleRule; used to implement presentational attributes.
  10  */
  11
  12 #ifndef nsMappedAttributes_h___
  13 #define nsMappedAttributes_h___
  14
  15 #include "AttrArray.h"
  16 #include "nsMappedAttributeElement.h"
  17 #include "mozilla/Attributes.h"
  18 #include "mozilla/ServoBindingTypes.h"
  19 #include "mozilla/MemoryReporting.h"
  20
  21 class nsAtom;
  22 class nsHTMLStyleSheet;
  23
  24 class nsMappedAttributes final {
  25  public:
  26   nsMappedAttributes(nsHTMLStyleSheet* aSheet,
  27                      nsMapRuleToAttributesFunc aMapRuleFunc);
  28
  29   // Do not return null.
  30   void* operator new(size_t size, uint32_t aAttrCount = 1) CPP_THROW_NEW;
  31   nsMappedAttributes* Clone(bool aWillAddAttr);
  32
  33   NS_INLINE_DECL_REFCOUNTING_WITH_DESTROY(nsMappedAttributes, LastRelease())
  34
  35   void SetAndSwapAttr(nsAtom* aAttrName, nsAttrValue& aValue,
  36                       bool* aValueWasSet);
  37   const nsAttrValue* GetAttr(const nsAtom* aAttrName) const;
  38   const nsAttrValue* GetAttr(const nsAString& aAttrName) const;
  39
  40   uint32_t Count() const { return mAttrCount; }
  41
  42   bool Equals(const nsMappedAttributes* aAttributes) const;
  43   PLDHashNumber HashValue() const;
  44
  45   void DropStyleSheetReference() { mSheet = nullptr; }
  46   void SetStyleSheet(nsHTMLStyleSheet* aSheet);
  47   nsHTMLStyleSheet* GetStyleSheet() { return mSheet; }
  48
  49   void SetRuleMapper(nsMapRuleToAttributesFunc aRuleMapper) {
  50     mRuleMapper = aRuleMapper;
  51   }
  52
  53   const nsAttrName* NameAt(uint32_t aPos) const {
  54     NS_ASSERTION(aPos < mAttrCount, "out-of-bounds");
  55     return &Attrs()[aPos].mName;
  56   }
  57   const nsAttrValue* AttrAt(uint32_t aPos) const {
  58     NS_ASSERTION(aPos < mAttrCount, "out-of-bounds");
  59     return &Attrs()[aPos].mValue;
  60   }
  61   // Remove the attr at position aPos.  The value of the attr is placed in
  62   // aValue; any value that was already in aValue is destroyed.
  63   void RemoveAttrAt(uint32_t aPos, nsAttrValue& aValue);
  64   const nsAttrName* GetExistingAttrNameFromQName(const nsAString& aName) const;
  65   int32_t IndexOfAttr(const nsAtom* aLocalName) const;
  66
  67   // Apply the contained mapper to the contained set of servo rules,
  68   // unless the servo rules have already been initialized.
  69   void LazilyResolveServoDeclaration(mozilla::dom::Document* aDocument);
  70
  71   // Obtain the contained servo declaration block
  72   // May return null if called before the inner block
  73   // has been (lazily) resolved
  74   const RefPtr<RawServoDeclarationBlock>& GetServoStyle() const {
  75     return mServoStyle;
  76   }
  77
  78   void ClearServoStyle() {
  79     MOZ_ASSERT(NS_IsMainThread());
  80     mServoStyle = nullptr;
  81   }
  82
  83   size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
  84
  85   static void Shutdown();
  86
  87  private:
  88   void LastRelease();
  89
  90   nsMappedAttributes(const nsMappedAttributes& aCopy);
  91   ~nsMappedAttributes();
  92
  93   struct InternalAttr {
  94     nsAttrName mName;
  95     nsAttrValue mValue;
  96   };
  97
  98   /**
  99    * Due to a compiler bug in VisualAge C++ for AIX, we need to return the
 100    * address of the first index into mAttrs here, instead of simply
 101    * returning mAttrs itself.
 102    *
 103    * See Bug 231104 for more information.
 104    */
 105   const InternalAttr* Attrs() const {
 106     return reinterpret_cast<const InternalAttr*>(&(mAttrs[0]));
 107   }
 108   InternalAttr* Attrs() {
 109     return reinterpret_cast<InternalAttr*>(&(mAttrs[0]));
 110   }
 111
 112   uint16_t mAttrCount;
 113 #ifdef DEBUG
 114   uint16_t mBufferSize;
 115 #endif
 116   nsHTMLStyleSheet* mSheet;  // weak
 117   nsMapRuleToAttributesFunc mRuleMapper;
 118   RefPtr<RawServoDeclarationBlock> mServoStyle;
 119   void* mAttrs[1];
 120
 121   static bool sShuttingDown;
 122
 123   // We're caching some memory to avoid trashing the allocator.
 124   // The memory stored at index N can hold N attribute values.
 125   static nsTArray<void*>* sCachedMappedAttributeAllocations;
 126 };
 127
 128 #endif /* nsMappedAttributes_h___ */