content/xul/templates/src/nsRDFConInstanceTestNode.h

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  15  * The Original Code is Mozilla Communicator client code.
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  22  * Contributor(s):
  23  *   Chris Waterson <waterson@netscape.com>
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  38
  39 #ifndef nsRDFConInstanceTestNode_h__
  40 #define nsRDFConInstanceTestNode_h__
  41
  42 #include "nscore.h"
  43 #include "nsFixedSizeAllocator.h"
  44 #include "nsRDFTestNode.h"
  45 #include "nsIRDFResource.h"
  46 #include "nsIRDFDataSource.h"
  47 #include "nsXULTemplateQueryProcessorRDF.h"
  48
  49 /**
  50  * Rule network node that tests if a resource is an RDF container, or
  51  * uses multi-attributes to ``contain'' other elements.
  52  */
  53 class nsRDFConInstanceTestNode : public nsRDFTestNode
  54 {
  55 public:
  56     enum Test { eFalse, eTrue, eDontCare };
  57
  58     nsRDFConInstanceTestNode(TestNode* aParent,
  59                              nsXULTemplateQueryProcessorRDF* aProcessor,
  60                              nsIAtom* aContainerVariable,
  61                              Test aContainer,
  62                              Test aEmpty);
  63
  64     virtual nsresult FilterInstantiations(InstantiationSet& aInstantiations,
  65                                           PRBool* aCantHandleYet) const;
  66
  67     virtual PRBool
  68     CanPropagate(nsIRDFResource* aSource,
  69                  nsIRDFResource* aProperty,
  70                  nsIRDFNode* aTarget,
  71                  Instantiation& aInitialBindings) const;
  72
  73     virtual void
  74     Retract(nsIRDFResource* aSource,
  75             nsIRDFResource* aProperty,
  76             nsIRDFNode* aTarget) const;
  77
  78
  79     class Element : public MemoryElement {
  80     protected:
  81         // Hide so that only Create() and Destroy() can be used to
  82         // allocate and deallocate from the heap
  83         static void* operator new(size_t) CPP_THROW_NEW { return 0; }
  84         static void operator delete(void*, size_t) {}
  85
  86     public:
  87         Element(nsIRDFResource* aContainer,
  88                 Test aContainerTest,
  89                 Test aEmptyTest)
  90             : mContainer(aContainer),
  91               mContainerTest(aContainerTest),
  92               mEmptyTest(aEmptyTest) {
  93             MOZ_COUNT_CTOR(nsRDFConInstanceTestNode::Element); }
  94
  95         virtual ~Element() { MOZ_COUNT_DTOR(nsRDFConInstanceTestNode::Element); }
  96
  97         static Element*
  98         Create(nsIRDFResource* aContainer,
  99                Test aContainerTest, Test aEmptyTest) {
 100             void* place = MemoryElement::gPool.Alloc(sizeof(Element));
 101             return place ? ::new (place) Element(aContainer, aContainerTest, aEmptyTest) : nsnull; }
 102
 103         void Destroy() {
 104             this->~Element();
 105             MemoryElement::gPool.Free(this, sizeof(Element));
 106         }
 107
 108         virtual const char* Type() const {
 109             return "nsRDFConInstanceTestNode::Element"; }
 110
 111         virtual PLHashNumber Hash() const {
 112             return (PLHashNumber(NS_PTR_TO_INT32(mContainer.get())) >> 4) ^
 113                 PLHashNumber(mContainerTest) ^
 114                 (PLHashNumber(mEmptyTest) << 4); }
 115
 116         virtual PRBool Equals(const MemoryElement& aElement) const {
 117             if (aElement.Type() == Type()) {
 118                 const Element& element = static_cast<const Element&>(aElement);
 119                 return mContainer == element.mContainer
 120                     && mContainerTest == element.mContainerTest
 121                     && mEmptyTest == element.mEmptyTest;
 122             }
 123             return PR_FALSE; }
 124
 125     protected:
 126         nsCOMPtr<nsIRDFResource> mContainer;
 127         Test mContainerTest;
 128         Test mEmptyTest;
 129     };
 130
 131 protected:
 132     nsXULTemplateQueryProcessorRDF* mProcessor;
 133     nsCOMPtr<nsIAtom> mContainerVariable;
 134     Test mContainer;
 135     Test mEmpty;
 136 };
 137
 138 #endif // nsRDFConInstanceTestNode_h__
 139