1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/content/xul/templates/src/nsRDFBinding.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,217 @@
1.4 +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#ifndef nsRDFBinding_h__
1.10 +#define nsRDFBinding_h__
1.11 +
1.12 +#include "nsAutoPtr.h"
1.13 +#include "nsIAtom.h"
1.14 +#include "nsIRDFResource.h"
1.15 +#include "nsISupportsImpl.h"
1.16 +
1.17 +class nsXULTemplateResultRDF;
1.18 +class nsBindingValues;
1.19 +
1.20 +/*
1.21 + * Classes related to storing bindings for RDF handling.
1.22 + */
1.23 +
1.24 +/*
1.25 + * a <binding> descriptors
1.26 + */
1.27 +class RDFBinding {
1.28 +
1.29 +public:
1.30 +
1.31 + nsCOMPtr<nsIAtom> mSubjectVariable;
1.32 + nsCOMPtr<nsIRDFResource> mPredicate;
1.33 + nsCOMPtr<nsIAtom> mTargetVariable;
1.34 +
1.35 + // indicates whether a binding is dependant on the result from a
1.36 + // previous binding
1.37 + bool mHasDependency;
1.38 +
1.39 + RDFBinding* mNext;
1.40 +
1.41 +private:
1.42 +
1.43 + friend class RDFBindingSet;
1.44 +
1.45 + RDFBinding(nsIAtom* aSubjectVariable,
1.46 + nsIRDFResource* aPredicate,
1.47 + nsIAtom* aTargetVariable)
1.48 + : mSubjectVariable(aSubjectVariable),
1.49 + mPredicate(aPredicate),
1.50 + mTargetVariable(aTargetVariable),
1.51 + mHasDependency(false),
1.52 + mNext(nullptr)
1.53 + {
1.54 + MOZ_COUNT_CTOR(RDFBinding);
1.55 + }
1.56 +
1.57 + ~RDFBinding()
1.58 + {
1.59 + MOZ_COUNT_DTOR(RDFBinding);
1.60 + }
1.61 +};
1.62 +
1.63 +/*
1.64 + * a collection of <binding> descriptors. This object is refcounted by
1.65 + * nsBindingValues objects and the query processor.
1.66 + */
1.67 +class RDFBindingSet MOZ_FINAL
1.68 +{
1.69 +private:
1.70 + // Private destructor, to discourage deletion outside of Release():
1.71 + ~RDFBindingSet();
1.72 +
1.73 + // the number of bindings
1.74 + int32_t mCount;
1.75 +
1.76 + // pointer to the first binding in a linked list
1.77 + RDFBinding* mFirst;
1.78 +
1.79 +public:
1.80 +
1.81 + RDFBindingSet()
1.82 + : mCount(0),
1.83 + mFirst(nullptr)
1.84 + {
1.85 + MOZ_COUNT_CTOR(RDFBindingSet);
1.86 + }
1.87 +
1.88 + NS_INLINE_DECL_REFCOUNTING(RDFBindingSet)
1.89 +
1.90 + int32_t Count() const { return mCount; }
1.91 +
1.92 + /*
1.93 + * Add a binding (aRef -> aPredicate -> aVar) to the set
1.94 + */
1.95 + nsresult
1.96 + AddBinding(nsIAtom* aVar, nsIAtom* aRef, nsIRDFResource* aPredicate);
1.97 +
1.98 + /*
1.99 + * Return true if the binding set contains a binding which would cause
1.100 + * the result to need resynchronizing for an RDF triple. The member
1.101 + * variable may be supplied as an optimization since bindings most
1.102 + * commonly use the member variable as the subject. If aMemberVariable
1.103 + * is set, aSubject must be the value of the member variable for the
1.104 + * result. The supplied binding values aBindingValues must be values
1.105 + * using this binding set (that is aBindingValues->GetBindingSet() == this)
1.106 + *
1.107 + * @param aSubject subject of the RDF triple
1.108 + * @param aPredicate predicate of the RDF triple
1.109 + * @param aTarget target of the RDF triple
1.110 + * @param aMemberVariable member variable for the query for the binding
1.111 + * @param aResult result to synchronize
1.112 + * @param aBindingValues the values for the bindings for the result
1.113 + */
1.114 + bool
1.115 + SyncAssignments(nsIRDFResource* aSubject,
1.116 + nsIRDFResource* aPredicate,
1.117 + nsIRDFNode* aTarget,
1.118 + nsIAtom* aMemberVariable,
1.119 + nsXULTemplateResultRDF* aResult,
1.120 + nsBindingValues& aBindingValues);
1.121 +
1.122 + /*
1.123 + * The query processor maintains a map of subjects to an array of results.
1.124 + * This is used such that when a new assertion is added to the RDF graph,
1.125 + * the results associated with the subject of that triple may be checked
1.126 + * to see if their bindings have changed. The AddDependencies method adds
1.127 + * these subject dependencies to the map.
1.128 + */
1.129 + void
1.130 + AddDependencies(nsIRDFResource* aSubject,
1.131 + nsXULTemplateResultRDF* aResult);
1.132 +
1.133 + /*
1.134 + * Remove the results from the dependencies map when results are deleted.
1.135 + */
1.136 + void
1.137 + RemoveDependencies(nsIRDFResource* aSubject,
1.138 + nsXULTemplateResultRDF* aResult);
1.139 +
1.140 + /*
1.141 + * The nsBindingValues classes stores an array of values, one for each
1.142 + * target symbol that could be set by the bindings in the set.
1.143 + * LookupTargetIndex determines the index into the array for a given
1.144 + * target symbol.
1.145 + */
1.146 + int32_t
1.147 + LookupTargetIndex(nsIAtom* aTargetVariable, RDFBinding** aBinding);
1.148 +};
1.149 +
1.150 +/*
1.151 + * A set of values of bindings. This object is used once per result.
1.152 + * This stores a reference to the binding set and an array of node values.
1.153 + * Since the binding set is used once per query and the values are
1.154 + * used once per result, we reduce size by only storing the value array's
1.155 + * length in the binding set. This is possible since the array is always
1.156 + * a fixed length for a particular binding set.
1.157 + *
1.158 + * XXX ndeakin We may want to revisit this later since it makes the code
1.159 + * more complicated.
1.160 + */
1.161 +class nsBindingValues
1.162 +{
1.163 +protected:
1.164 +
1.165 + // the binding set
1.166 + nsRefPtr<RDFBindingSet> mBindings;
1.167 +
1.168 + /*
1.169 + * A set of values for variable bindings. To look up a binding value,
1.170 + * scan through the binding set in mBindings for the right target atom.
1.171 + * Its index will correspond to the index in this array. The size of this
1.172 + * array is determined by the RDFBindingSet's Count().
1.173 + */
1.174 + nsCOMPtr<nsIRDFNode>* mValues;
1.175 +
1.176 +public:
1.177 +
1.178 + nsBindingValues()
1.179 + : mBindings(nullptr),
1.180 + mValues(nullptr)
1.181 + {
1.182 + MOZ_COUNT_CTOR(nsBindingValues);
1.183 + }
1.184 +
1.185 + ~nsBindingValues();
1.186 +
1.187 +
1.188 + /**
1.189 + * Clear the binding set, to be called when the nsBindingValues is deleted
1.190 + * or a new binding set is being set.
1.191 + */
1.192 + void ClearBindingSet();
1.193 +
1.194 + RDFBindingSet* GetBindingSet() { return mBindings; }
1.195 +
1.196 + /**
1.197 + * Set the binding set to use. This needs to be called once a rule matches
1.198 + * since it is then known which bindings will apply.
1.199 + */
1.200 + nsresult SetBindingSet(RDFBindingSet* aBindings);
1.201 +
1.202 + nsCOMPtr<nsIRDFNode>* ValuesArray() { return mValues; }
1.203 +
1.204 + /*
1.205 + * Retrieve the assignment for a particular variable
1.206 + */
1.207 + void
1.208 + GetAssignmentFor(nsXULTemplateResultRDF* aResult,
1.209 + nsIAtom* aVar,
1.210 + nsIRDFNode** aValue);
1.211 +
1.212 + /*
1.213 + * Remove depenedencies the bindings have on particular resources
1.214 + */
1.215 + void
1.216 + RemoveDependencies(nsIRDFResource* aSubject,
1.217 + nsXULTemplateResultRDF* aResult);
1.218 +};
1.219 +
1.220 +#endif // nsRDFBinding_h__
