michael@0: /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef nsRDFBinding_h__
michael@0: #define nsRDFBinding_h__
michael@0: 
michael@0: #include "nsAutoPtr.h"
michael@0: #include "nsIAtom.h"
michael@0: #include "nsIRDFResource.h"
michael@0: #include "nsISupportsImpl.h"
michael@0: 
michael@0: class nsXULTemplateResultRDF;
michael@0: class nsBindingValues;
michael@0: 
michael@0: /*
michael@0:  * Classes related to storing bindings for RDF handling.
michael@0:  */
michael@0: 
michael@0: /*
michael@0:  * a  <binding> descriptors
michael@0:  */
michael@0: class RDFBinding {
michael@0: 
michael@0: public:
michael@0: 
michael@0:     nsCOMPtr<nsIAtom>        mSubjectVariable;
michael@0:     nsCOMPtr<nsIRDFResource> mPredicate;
michael@0:     nsCOMPtr<nsIAtom>        mTargetVariable;
michael@0: 
michael@0:     // indicates whether a binding is dependant on the result from a
michael@0:     // previous binding
michael@0:     bool                     mHasDependency;
michael@0: 
michael@0:     RDFBinding*              mNext;
michael@0: 
michael@0: private:
michael@0: 
michael@0:     friend class RDFBindingSet;
michael@0: 
michael@0:     RDFBinding(nsIAtom* aSubjectVariable,
michael@0:                nsIRDFResource* aPredicate,
michael@0:                nsIAtom* aTargetVariable)
michael@0:       : mSubjectVariable(aSubjectVariable),
michael@0:         mPredicate(aPredicate),
michael@0:         mTargetVariable(aTargetVariable),
michael@0:         mHasDependency(false),
michael@0:         mNext(nullptr)
michael@0:     {
michael@0:         MOZ_COUNT_CTOR(RDFBinding);
michael@0:     }
michael@0: 
michael@0:     ~RDFBinding()
michael@0:     {
michael@0:         MOZ_COUNT_DTOR(RDFBinding);
michael@0:     }
michael@0: };
michael@0: 
michael@0: /*
michael@0:  * a collection of <binding> descriptors. This object is refcounted by
michael@0:  * nsBindingValues objects and the query processor.
michael@0:  */
michael@0: class RDFBindingSet MOZ_FINAL
michael@0: {
michael@0: private:
michael@0:     // Private destructor, to discourage deletion outside of Release():
michael@0:     ~RDFBindingSet();
michael@0: 
michael@0:     // the number of bindings
michael@0:     int32_t mCount;
michael@0: 
michael@0:     // pointer to the first binding in a linked list
michael@0:     RDFBinding* mFirst;
michael@0: 
michael@0: public:
michael@0: 
michael@0:     RDFBindingSet()
michael@0:         : mCount(0),
michael@0:           mFirst(nullptr)
michael@0:     {
michael@0:         MOZ_COUNT_CTOR(RDFBindingSet);
michael@0:     }
michael@0: 
michael@0:     NS_INLINE_DECL_REFCOUNTING(RDFBindingSet)
michael@0: 
michael@0:     int32_t Count() const { return mCount; }
michael@0: 
michael@0:     /*
michael@0:      * Add a binding (aRef -> aPredicate -> aVar) to the set
michael@0:      */
michael@0:     nsresult
michael@0:     AddBinding(nsIAtom* aVar, nsIAtom* aRef, nsIRDFResource* aPredicate);
michael@0: 
michael@0:     /*
michael@0:      * Return true if the binding set contains a binding which would cause
michael@0:      * the result to need resynchronizing for an RDF triple. The member
michael@0:      * variable may be supplied as an optimization since bindings most
michael@0:      * commonly use the member variable as the subject. If aMemberVariable
michael@0:      * is set, aSubject must be the value of the member variable for the
michael@0:      * result. The supplied binding values aBindingValues must be values
michael@0:      * using this binding set (that is aBindingValues->GetBindingSet() == this)
michael@0:      *
michael@0:      * @param aSubject subject of the RDF triple
michael@0:      * @param aPredicate predicate of the RDF triple
michael@0:      * @param aTarget target of the RDF triple
michael@0:      * @param aMemberVariable member variable for the query for the binding
michael@0:      * @param aResult result to synchronize
michael@0:      * @param aBindingValues the values for the bindings for the result
michael@0:      */
michael@0:     bool
michael@0:     SyncAssignments(nsIRDFResource* aSubject,
michael@0:                     nsIRDFResource* aPredicate,
michael@0:                     nsIRDFNode* aTarget,
michael@0:                     nsIAtom* aMemberVariable,
michael@0:                     nsXULTemplateResultRDF* aResult,
michael@0:                     nsBindingValues& aBindingValues);
michael@0: 
michael@0:     /*
michael@0:      * The query processor maintains a map of subjects to an array of results.
michael@0:      * This is used such that when a new assertion is added to the RDF graph,
michael@0:      * the results associated with the subject of that triple may be checked
michael@0:      * to see if their bindings have changed. The AddDependencies method adds
michael@0:      * these subject dependencies to the map.
michael@0:      */
michael@0:     void
michael@0:     AddDependencies(nsIRDFResource* aSubject,
michael@0:                     nsXULTemplateResultRDF* aResult);
michael@0: 
michael@0:     /*
michael@0:      * Remove the results from the dependencies map when results are deleted.
michael@0:      */
michael@0:     void
michael@0:     RemoveDependencies(nsIRDFResource* aSubject,
michael@0:                        nsXULTemplateResultRDF* aResult);
michael@0: 
michael@0:     /*
michael@0:      * The nsBindingValues classes stores an array of values, one for each
michael@0:      * target symbol that could be set by the bindings in the set.
michael@0:      * LookupTargetIndex determines the index into the array for a given
michael@0:      * target symbol.
michael@0:      */
michael@0:     int32_t
michael@0:     LookupTargetIndex(nsIAtom* aTargetVariable, RDFBinding** aBinding);
michael@0: };
michael@0: 
michael@0: /*
michael@0:  * A set of values of bindings. This object is used once per result.
michael@0:  * This stores a reference to the binding set and an array of node values.
michael@0:  * Since the binding set is used once per query and the values are
michael@0:  * used once per result, we reduce size by only storing the value array's
michael@0:  * length in the binding set. This is possible since the array is always
michael@0:  * a fixed length for a particular binding set.
michael@0:  *
michael@0:  * XXX ndeakin We may want to revisit this later since it makes the code
michael@0:  *             more complicated.
michael@0:  */
michael@0: class nsBindingValues
michael@0: {
michael@0: protected:
michael@0: 
michael@0:     // the binding set
michael@0:     nsRefPtr<RDFBindingSet> mBindings;
michael@0: 
michael@0:     /*
michael@0:      * A set of values for variable bindings. To look up a binding value,
michael@0:      * scan through the binding set in mBindings for the right target atom.
michael@0:      * Its index will correspond to the index in this array. The size of this
michael@0:      * array is determined by the RDFBindingSet's Count().
michael@0:      */
michael@0:     nsCOMPtr<nsIRDFNode>* mValues;
michael@0: 
michael@0: public:
michael@0: 
michael@0:     nsBindingValues()
michael@0:       : mBindings(nullptr),
michael@0:         mValues(nullptr)
michael@0:     {
michael@0:         MOZ_COUNT_CTOR(nsBindingValues);
michael@0:     }
michael@0: 
michael@0:     ~nsBindingValues();
michael@0: 
michael@0: 
michael@0:     /**
michael@0:      * Clear the binding set, to be called when the nsBindingValues is deleted
michael@0:      * or a new binding set is being set.
michael@0:      */
michael@0:     void ClearBindingSet();
michael@0: 
michael@0:     RDFBindingSet* GetBindingSet() { return mBindings; }
michael@0: 
michael@0:     /**
michael@0:      * Set the binding set to use. This needs to be called once a rule matches
michael@0:      * since it is then known which bindings will apply.
michael@0:      */
michael@0:     nsresult SetBindingSet(RDFBindingSet* aBindings);
michael@0: 
michael@0:     nsCOMPtr<nsIRDFNode>* ValuesArray() { return mValues; }
michael@0: 
michael@0:     /*
michael@0:      * Retrieve the assignment for a particular variable
michael@0:      */
michael@0:     void
michael@0:     GetAssignmentFor(nsXULTemplateResultRDF* aResult,
michael@0:                      nsIAtom* aVar,
michael@0:                      nsIRDFNode** aValue);
michael@0: 
michael@0:     /*
michael@0:      * Remove depenedencies the bindings have on particular resources
michael@0:      */
michael@0:     void
michael@0:     RemoveDependencies(nsIRDFResource* aSubject,
michael@0:                        nsXULTemplateResultRDF* aResult);
michael@0: };
michael@0: 
michael@0: #endif // nsRDFBinding_h__