content/xul/templates/src/nsRDFPropertyTestNode.h

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   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/
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  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 Communicator client code.
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  17  * The Initial Developer of the Original Code is
  18  * Netscape Communications Corporation.
  19  * Portions created by the Initial Developer are Copyright (C) 1998
  20  * the Initial Developer. All Rights Reserved.
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  22  * Contributor(s):
  23  *   Chris Waterson <waterson@netscape.com>
  24  *
  25  * Alternatively, the contents of this file may be used under the terms of
  26  * either of the GNU General Public License Version 2 or later (the "GPL"),
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  36  *
  37  * ***** END LICENSE BLOCK ***** */
  38
  39 #ifndef nsRDFPropertyTestNode_h__
  40 #define nsRDFPropertyTestNode_h__
  41
  42 #include "nscore.h"
  43 #include "nsRDFTestNode.h"
  44 #include "nsIRDFDataSource.h"
  45 #include "nsIRDFResource.h"
  46 #include "nsXULTemplateQueryProcessorRDF.h"
  47
  48 class nsRDFPropertyTestNode : public nsRDFTestNode
  49 {
  50 public:
  51     /**
  52      * Both source and target unbound (?source ^property ?target)
  53      */
  54     nsRDFPropertyTestNode(TestNode* aParent,
  55                           nsXULTemplateQueryProcessorRDF* aProcessor,
  56                           nsIAtom* aSourceVariable,
  57                           nsIRDFResource* aProperty,
  58                           nsIAtom* aTargetVariable);
  59
  60     /**
  61      * Source bound, target unbound (source ^property ?target)
  62      */
  63     nsRDFPropertyTestNode(TestNode* aParent,
  64                           nsXULTemplateQueryProcessorRDF* aProcessor,
  65                           nsIRDFResource* aSource,
  66                           nsIRDFResource* aProperty,
  67                           nsIAtom* aTargetVariable);
  68
  69     /**
  70      * Source unbound, target bound (?source ^property target)
  71      */
  72     nsRDFPropertyTestNode(TestNode* aParent,
  73                           nsXULTemplateQueryProcessorRDF* aProcessor,
  74                           nsIAtom* aSourceVariable,
  75                           nsIRDFResource* aProperty,
  76                           nsIRDFNode* aTarget);
  77
  78     virtual nsresult FilterInstantiations(InstantiationSet& aInstantiations,
  79                                           PRBool* aCantHandleYet) const;
  80
  81     virtual PRBool
  82     CanPropagate(nsIRDFResource* aSource,
  83                  nsIRDFResource* aProperty,
  84                  nsIRDFNode* aTarget,
  85                  Instantiation& aInitialBindings) const;
  86
  87     virtual void
  88     Retract(nsIRDFResource* aSource,
  89             nsIRDFResource* aProperty,
  90             nsIRDFNode* aTarget) const;
  91
  92
  93     class Element : public MemoryElement {
  94     protected:
  95         // Hide so that only Create() and Destroy() can be used to
  96         // allocate and deallocate from the heap
  97         static void* operator new(size_t) CPP_THROW_NEW { return 0; }
  98         static void operator delete(void*, size_t) {}
  99
 100     public:
 101         Element(nsIRDFResource* aSource,
 102                 nsIRDFResource* aProperty,
 103                 nsIRDFNode* aTarget)
 104             : mSource(aSource),
 105               mProperty(aProperty),
 106               mTarget(aTarget) {
 107             MOZ_COUNT_CTOR(nsRDFPropertyTestNode::Element); }
 108
 109         virtual ~Element() { MOZ_COUNT_DTOR(nsRDFPropertyTestNode::Element); }
 110
 111         static Element*
 112         Create(nsIRDFResource* aSource,
 113                nsIRDFResource* aProperty,
 114                nsIRDFNode* aTarget) {
 115             void* place = MemoryElement::gPool.Alloc(sizeof(Element));
 116             return place ? ::new (place) Element(aSource, aProperty, aTarget) : nsnull; }
 117
 118         void Destroy() {
 119             this->~Element();
 120             MemoryElement::gPool.Free(this, sizeof(Element));
 121         }
 122
 123         virtual const char* Type() const {
 124             return "nsRDFPropertyTestNode::Element"; }
 125
 126         virtual PLHashNumber Hash() const {
 127             return PLHashNumber(NS_PTR_TO_INT32(mSource.get())) ^
 128                 (PLHashNumber(NS_PTR_TO_INT32(mProperty.get())) >> 4) ^
 129                 (PLHashNumber(NS_PTR_TO_INT32(mTarget.get())) >> 12); }
 130
 131         virtual PRBool Equals(const MemoryElement& aElement) const {
 132             if (aElement.Type() == Type()) {
 133                 const Element& element = static_cast<const Element&>(aElement);
 134                 return mSource == element.mSource
 135                     && mProperty == element.mProperty
 136                     && mTarget == element.mTarget;
 137             }
 138             return PR_FALSE; }
 139
 140     protected:
 141         nsCOMPtr<nsIRDFResource> mSource;
 142         nsCOMPtr<nsIRDFResource> mProperty;
 143         nsCOMPtr<nsIRDFNode> mTarget;
 144     };
 145
 146 protected:
 147     nsXULTemplateQueryProcessorRDF* mProcessor;
 148     nsCOMPtr<nsIAtom>        mSourceVariable;
 149     nsCOMPtr<nsIRDFResource> mSource;
 150     nsCOMPtr<nsIRDFResource> mProperty;
 151     nsCOMPtr<nsIAtom>        mTargetVariable;
 152     nsCOMPtr<nsIRDFNode>     mTarget;
 153 };
 154
 155 #endif // nsRDFPropertyTestNode_h__