src/xmlpatterns/schema/qxsdparticlechecker.cpp
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     1 /****************************************************************************
       
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    38 ** $QT_END_LICENSE$
       
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    40 ****************************************************************************/
       
    41 
       
    42 #include "qxsdparticlechecker_p.h"
       
    43 
       
    44 #include "qxsdelement_p.h"
       
    45 #include "qxsdmodelgroup_p.h"
       
    46 #include "qxsdschemahelper_p.h"
       
    47 #include "qxsdstatemachine_p.h"
       
    48 #include "qxsdstatemachinebuilder_p.h"
       
    49 #include "qxsdtypechecker_p.h"
       
    50 
       
    51 #include <QtCore/QFile>
       
    52 
       
    53 QT_BEGIN_NAMESPACE
       
    54 
       
    55 using namespace QPatternist;
       
    56 
       
    57 namespace QPatternist
       
    58 {
       
    59     /**
       
    60      * This template specialization is picked up by XsdStateMachine and allows us
       
    61      * to print nice edge labels.
       
    62      */
       
    63     template <>
       
    64     QString XsdStateMachine<XsdTerm::Ptr>::transitionTypeToString(XsdTerm::Ptr term) const
       
    65     {
       
    66         if (!term)
       
    67             return QLatin1String("(empty)");
       
    68 
       
    69         if (term->isElement()) {
       
    70             return XsdElement::Ptr(term)->displayName(m_namePool);
       
    71         } else if (term->isWildcard()) {
       
    72             const XsdWildcard::Ptr wildcard(term);
       
    73             return QLatin1String("(wildcard)");
       
    74         } else {
       
    75             return QString();
       
    76         }
       
    77     }
       
    78 }
       
    79 
       
    80 /**
       
    81  * This method is used by the isUPAConform method to check whether @p term and @p otherTerm
       
    82  * are the same resp. match each other.
       
    83  */
       
    84 static bool termMatches(const XsdTerm::Ptr &term, const XsdTerm::Ptr &otherTerm, const NamePool::Ptr &namePool)
       
    85 {
       
    86     if (term->isElement()) {
       
    87         const XsdElement::Ptr element(term);
       
    88 
       
    89         if (otherTerm->isElement()) {
       
    90             // both, the term and the other term are elements
       
    91 
       
    92             const XsdElement::Ptr otherElement(otherTerm);
       
    93 
       
    94             // if they have the same name they match
       
    95             if (element->name(namePool) == otherElement->name(namePool))
       
    96                 return true;
       
    97 
       
    98         } else if (otherTerm->isWildcard()) {
       
    99             // the term is an element and the other term a wildcard
       
   100 
       
   101             const XsdWildcard::Ptr wildcard(otherTerm);
       
   102 
       
   103             // wildcards using XsdWildcard::absentNamespace, so we have to fix that here
       
   104             QXmlName name = element->name(namePool);
       
   105             if (name.namespaceURI() == StandardNamespaces::empty)
       
   106                 name.setNamespaceURI(namePool->allocateNamespace(XsdWildcard::absentNamespace()));
       
   107 
       
   108             // if the wildcards namespace constraint allows the elements name, they match
       
   109             if (XsdSchemaHelper::wildcardAllowsExpandedName(name, wildcard, namePool))
       
   110                 return true;
       
   111         }
       
   112     } else if (term->isWildcard()) {
       
   113         const XsdWildcard::Ptr wildcard(term);
       
   114 
       
   115         if (otherTerm->isElement()) {
       
   116             // the term is a wildcard and the other term an element
       
   117 
       
   118             const XsdElement::Ptr otherElement(otherTerm);
       
   119 
       
   120             // wildcards using XsdWildcard::absentNamespace, so we have to fix that here
       
   121             QXmlName name = otherElement->name(namePool);
       
   122             if (name.namespaceURI() == StandardNamespaces::empty)
       
   123                 name.setNamespaceURI(namePool->allocateNamespace(XsdWildcard::absentNamespace()));
       
   124 
       
   125             // if the wildcards namespace constraint allows the elements name, they match
       
   126             if (XsdSchemaHelper::wildcardAllowsExpandedName(name, wildcard, namePool))
       
   127                 return true;
       
   128 
       
   129         } else if (otherTerm->isWildcard()) {
       
   130             // both, the term and the other term are wildcards
       
   131 
       
   132             const XsdWildcard::Ptr otherWildcard(otherTerm);
       
   133 
       
   134             // check if the range of the wildcard overlaps.
       
   135             const XsdWildcard::Ptr intersectionWildcard = XsdSchemaHelper::wildcardIntersection(wildcard, otherWildcard);
       
   136             if (!intersectionWildcard ||
       
   137                 (intersectionWildcard && !(intersectionWildcard->namespaceConstraint()->variety() != XsdWildcard::NamespaceConstraint::Not && intersectionWildcard->namespaceConstraint()->namespaces().isEmpty())))
       
   138                 return true;
       
   139         }
       
   140     }
       
   141 
       
   142     return false;
       
   143 }
       
   144 
       
   145 /**
       
   146  * This method is used by the subsumes algorithm to check whether the @p derivedTerm is validly derived from the @p baseTerm.
       
   147  *
       
   148  * @param baseTerm The term of the base component (type or group).
       
   149  * @param derivedTerm The term of the derived component (type or group).
       
   150  * @param particles A hash to map the passed base and derived term to the particles they belong to.
       
   151  * @param context The schema context.
       
   152  * @param errorMsg The error message in the case that an error occurs.
       
   153  */
       
   154 static bool derivedTermValid(const XsdTerm::Ptr &baseTerm, const XsdTerm::Ptr &derivedTerm, const QHash<XsdTerm::Ptr, XsdParticle::Ptr> &particles, const XsdSchemaContext::Ptr &context, QString &errorMsg)
       
   155 {
       
   156     const NamePool::Ptr namePool(context->namePool());
       
   157 
       
   158     // find the particles where the base and derived term belongs to
       
   159     const XsdParticle::Ptr baseParticle = particles.value(baseTerm);
       
   160     const XsdParticle::Ptr derivedParticle = particles.value(derivedTerm);
       
   161 
       
   162     // check that an empty particle can not be derived from a non-empty particle
       
   163     if (derivedParticle && baseParticle) {
       
   164         if (XsdSchemaHelper::isParticleEmptiable(derivedParticle) && !XsdSchemaHelper::isParticleEmptiable(baseParticle)) {
       
   165             errorMsg = QtXmlPatterns::tr("Empty particle cannot be derived from non-empty particle.");
       
   166             return false;
       
   167         }
       
   168     }
       
   169 
       
   170     if (baseTerm->isElement()) {
       
   171         const XsdElement::Ptr element(baseTerm);
       
   172 
       
   173         if (derivedTerm->isElement()) {
       
   174             // if both terms are elements
       
   175 
       
   176             const XsdElement::Ptr derivedElement(derivedTerm);
       
   177 
       
   178             // check names are equal
       
   179             if (element->name(namePool) != derivedElement->name(namePool)) {
       
   180                 errorMsg = QtXmlPatterns::tr("Derived particle is missing element %1.").arg(formatKeyword(element->displayName(namePool)));
       
   181                 return false;
       
   182             }
       
   183 
       
   184             // check value constraints are equal (if available)
       
   185             if (element->valueConstraint() && element->valueConstraint()->variety() == XsdElement::ValueConstraint::Fixed) {
       
   186                 if (!derivedElement->valueConstraint()) {
       
   187                     errorMsg = QtXmlPatterns::tr("Derived element %1 is missing value constraint as defined in base particle.").arg(formatKeyword(derivedElement->displayName(namePool)));
       
   188                     return false;
       
   189                 }
       
   190 
       
   191                 if (derivedElement->valueConstraint()->variety() != XsdElement::ValueConstraint::Fixed) {
       
   192                     errorMsg = QtXmlPatterns::tr("Derived element %1 has weaker value constraint than base particle.").arg(formatKeyword(derivedElement->displayName(namePool)));
       
   193                     return false;
       
   194                 }
       
   195 
       
   196                 const QSourceLocation dummyLocation(QUrl(QLatin1String("http://dummy.org")), 1, 1);
       
   197                 const XsdTypeChecker checker(context, QVector<QXmlName>(), dummyLocation);
       
   198                 if (!checker.valuesAreEqual(element->valueConstraint()->value(), derivedElement->valueConstraint()->value(), derivedElement->type())) {
       
   199                     errorMsg = QtXmlPatterns::tr("Fixed value constraint of element %1 differs from value constraint in base particle.").arg(formatKeyword(derivedElement->displayName(namePool)));
       
   200                     return false;
       
   201                 }
       
   202             }
       
   203 
       
   204             // check that a derived element can not be nillable if the base element is not nillable
       
   205             if (!element->isNillable() && derivedElement->isNillable()) {
       
   206                 errorMsg = QtXmlPatterns::tr("Derived element %1 cannot be nillable as base element is not nillable.").arg(formatKeyword(derivedElement->displayName(namePool)));
       
   207                 return false;
       
   208             }
       
   209 
       
   210             // check that the constraints of the derived element are more strict then the constraints of the base element
       
   211             const XsdElement::BlockingConstraints baseConstraints = element->disallowedSubstitutions();
       
   212             const XsdElement::BlockingConstraints derivedConstraints = derivedElement->disallowedSubstitutions();
       
   213             if (((baseConstraints & XsdElement::RestrictionConstraint) && !(derivedConstraints & XsdElement::RestrictionConstraint)) ||
       
   214                 ((baseConstraints & XsdElement::ExtensionConstraint) && !(derivedConstraints & XsdElement::ExtensionConstraint)) ||
       
   215                 ((baseConstraints & XsdElement::SubstitutionConstraint) && !(derivedConstraints & XsdElement::SubstitutionConstraint))) {
       
   216                 errorMsg = QtXmlPatterns::tr("Block constraints of derived element %1 must not be more weaker than in the base element.").arg(formatKeyword(derivedElement->displayName(namePool)));
       
   217                 return false;
       
   218             }
       
   219 
       
   220             // if the type of both elements is the same we can stop testing here
       
   221             if (element->type()->name(namePool) == derivedElement->type()->name(namePool))
       
   222                 return true;
       
   223 
       
   224             // check that the type of the derived element can validly derived from the type of the base element
       
   225             if (derivedElement->type()->isSimpleType()) {
       
   226                 if (!XsdSchemaHelper::isSimpleDerivationOk(derivedElement->type(), element->type(), SchemaType::DerivationConstraints())) {
       
   227                     errorMsg = QtXmlPatterns::tr("Simple type of derived element %1 cannot be validly derived from base element.").arg(formatKeyword(derivedElement->displayName(namePool)));
       
   228                     return false;
       
   229                 }
       
   230             } else if (derivedElement->type()->isComplexType()) {
       
   231                 if (!XsdSchemaHelper::isComplexDerivationOk(derivedElement->type(), element->type(), SchemaType::DerivationConstraints())) {
       
   232                     errorMsg = QtXmlPatterns::tr("Complex type of derived element %1 cannot be validly derived from base element.").arg(formatKeyword(derivedElement->displayName(namePool)));
       
   233                     return false;
       
   234                 }
       
   235             }
       
   236 
       
   237             // if both, derived and base element, have a complex type that contains a particle itself, apply the subsumes algorithm
       
   238             // recursive on their particles
       
   239             if (element->type()->isComplexType() && derivedElement->type()->isComplexType()) {
       
   240                 if (element->type()->isDefinedBySchema() && derivedElement->type()->isDefinedBySchema()) {
       
   241                     const XsdComplexType::Ptr baseType(element->type());
       
   242                     const XsdComplexType::Ptr derivedType(derivedElement->type());
       
   243                     if ((baseType->contentType()->variety() == XsdComplexType::ContentType::ElementOnly ||
       
   244                         baseType->contentType()->variety() == XsdComplexType::ContentType::Mixed) &&
       
   245                         (derivedType->contentType()->variety() == XsdComplexType::ContentType::ElementOnly ||
       
   246                          derivedType->contentType()->variety() == XsdComplexType::ContentType::Mixed)) {
       
   247 
       
   248                         return XsdParticleChecker::subsumes(baseType->contentType()->particle(), derivedType->contentType()->particle(), context, errorMsg);
       
   249                     }
       
   250                 }
       
   251             }
       
   252 
       
   253             return true;
       
   254         } else if (derivedTerm->isWildcard()) {
       
   255             // derive a wildcard from an element is not allowed
       
   256             errorMsg = QtXmlPatterns::tr("Element %1 is missing in derived particle.").arg(formatKeyword(element->displayName(namePool)));
       
   257             return false;
       
   258         }
       
   259     } else if (baseTerm->isWildcard()) {
       
   260         const XsdWildcard::Ptr wildcard(baseTerm);
       
   261 
       
   262         if (derivedTerm->isElement()) {
       
   263             // the base term is a wildcard and derived term an element
       
   264 
       
   265             const XsdElement::Ptr derivedElement(derivedTerm);
       
   266 
       
   267             // wildcards using XsdWildcard::absentNamespace, so we have to fix that here
       
   268             QXmlName name = derivedElement->name(namePool);
       
   269             if (name.namespaceURI() == StandardNamespaces::empty)
       
   270                 name.setNamespaceURI(namePool->allocateNamespace(XsdWildcard::absentNamespace()));
       
   271 
       
   272             // check that name of the element is allowed by the wildcards namespace constraint
       
   273             if (!XsdSchemaHelper::wildcardAllowsExpandedName(name, wildcard, namePool)) {
       
   274                 errorMsg = QtXmlPatterns::tr("Element %1 does not match namespace constraint of wildcard in base particle.").arg(formatKeyword(derivedElement->displayName(namePool)));
       
   275                 return false;
       
   276             }
       
   277 
       
   278         } else if (derivedTerm->isWildcard()) {
       
   279             // both, derived and base term are wildcards
       
   280 
       
   281             const XsdWildcard::Ptr derivedWildcard(derivedTerm);
       
   282 
       
   283             // check that the derived wildcard is a valid subset of the base wildcard
       
   284             if (!XsdSchemaHelper::isWildcardSubset(derivedWildcard, wildcard)) {
       
   285                 errorMsg = QtXmlPatterns::tr("Wildcard in derived particle is not a valid subset of wildcard in base particle.");
       
   286                 return false;
       
   287             }
       
   288 
       
   289             if (!XsdSchemaHelper::checkWildcardProcessContents(wildcard, derivedWildcard)) {
       
   290                 errorMsg = QtXmlPatterns::tr("processContent of wildcard in derived particle is weaker than wildcard in base particle.");
       
   291                 return false;
       
   292             }
       
   293         }
       
   294 
       
   295         return true;
       
   296     }
       
   297 
       
   298     return false;
       
   299 }
       
   300 
       
   301 typedef QHash<QXmlName, XsdElement::Ptr> ElementHash;
       
   302 
       
   303 /**
       
   304  * Internal helper method that checks if the given @p particle contains an element with the
       
   305  * same name and type twice.
       
   306  */
       
   307 static bool hasDuplicatedElementsInternal(const XsdParticle::Ptr &particle, const NamePool::Ptr &namePool, ElementHash &hash, XsdElement::Ptr &conflictingElement)
       
   308 {
       
   309     const XsdTerm::Ptr term = particle->term();
       
   310     if (term->isElement()) {
       
   311         const XsdElement::Ptr mainElement(term);
       
   312         XsdElement::List substGroups = mainElement->substitutionGroups();
       
   313         if (substGroups.isEmpty())
       
   314             substGroups << mainElement;
       
   315 
       
   316         for (int i = 0; i < substGroups.count(); ++i) {
       
   317             const XsdElement::Ptr element = substGroups.at(i);
       
   318             if (hash.contains(element->name(namePool))) {
       
   319                 if (element->type()->name(namePool) != hash.value(element->name(namePool))->type()->name(namePool)) {
       
   320                     conflictingElement = element;
       
   321                     return true;
       
   322                 }
       
   323             } else {
       
   324                 hash.insert(element->name(namePool), element);
       
   325             }
       
   326         }
       
   327     } else if (term->isModelGroup()) {
       
   328         const XsdModelGroup::Ptr group(term);
       
   329         const XsdParticle::List particles = group->particles();
       
   330         for (int i = 0; i < particles.count(); ++i) {
       
   331             if (hasDuplicatedElementsInternal(particles.at(i), namePool, hash, conflictingElement))
       
   332                 return true;
       
   333         }
       
   334     }
       
   335 
       
   336     return false;
       
   337 }
       
   338 
       
   339 bool XsdParticleChecker::hasDuplicatedElements(const XsdParticle::Ptr &particle, const NamePool::Ptr &namePool, XsdElement::Ptr &conflictingElement)
       
   340 {
       
   341     ElementHash hash;
       
   342     return hasDuplicatedElementsInternal(particle, namePool, hash, conflictingElement);
       
   343 }
       
   344 
       
   345 bool XsdParticleChecker::isUPAConform(const XsdParticle::Ptr &particle, const NamePool::Ptr &namePool)
       
   346 {
       
   347     /**
       
   348      * The algorithm is implemented like described in http://www.ltg.ed.ac.uk/~ht/XML_Europe_2003.html#S2.2
       
   349      */
       
   350 
       
   351     // create a state machine for the given particle
       
   352     XsdStateMachine<XsdTerm::Ptr> stateMachine(namePool);
       
   353 
       
   354     XsdStateMachineBuilder builder(&stateMachine, namePool);
       
   355     const XsdStateMachine<XsdTerm::Ptr>::StateId endState = builder.reset();
       
   356     const XsdStateMachine<XsdTerm::Ptr>::StateId startState = builder.buildParticle(particle, endState);
       
   357     builder.addStartState(startState);
       
   358 
       
   359 /*
       
   360     static int counter = 0;
       
   361     {
       
   362         QFile file(QString("/tmp/file_upa%1.dot").arg(counter));
       
   363         file.open(QIODevice::WriteOnly);
       
   364         stateMachine.outputGraph(&file, "Base");
       
   365         file.close();
       
   366     }
       
   367     ::system(QString("dot -Tpng /tmp/file_upa%1.dot -o/tmp/file_upa%1.png").arg(counter).toLatin1().data());
       
   368 */
       
   369     const XsdStateMachine<XsdTerm::Ptr> dfa = stateMachine.toDFA();
       
   370 /*
       
   371     {
       
   372         QFile file(QString("/tmp/file_upa%1dfa.dot").arg(counter));
       
   373         file.open(QIODevice::WriteOnly);
       
   374         dfa.outputGraph(&file, "Base");
       
   375         file.close();
       
   376     }
       
   377     ::system(QString("dot -Tpng /tmp/file_upa%1dfa.dot -o/tmp/file_upa%1dfa.png").arg(counter).toLatin1().data());
       
   378 */
       
   379     const QHash<XsdStateMachine<XsdTerm::Ptr>::StateId, XsdStateMachine<XsdTerm::Ptr>::StateType> states = dfa.states();
       
   380     const QHash<XsdStateMachine<XsdTerm::Ptr>::StateId, QHash<XsdTerm::Ptr, QVector<XsdStateMachine<XsdTerm::Ptr>::StateId> > > transitions = dfa.transitions();
       
   381 
       
   382     // the basic idea of that algorithm is to iterate over all states of that machine and check that no two edges
       
   383     // that match on the same term leave a state, so for a given term it should always be obvious which edge to take
       
   384     QHashIterator<XsdStateMachine<XsdTerm::Ptr>::StateId, XsdStateMachine<XsdTerm::Ptr>::StateType> stateIt(states);
       
   385     while (stateIt.hasNext()) { // iterate over all states
       
   386         stateIt.next();
       
   387 
       
   388         // fetch all transitions the current state allows
       
   389         const QHash<XsdTerm::Ptr, QVector<XsdStateMachine<XsdTerm::Ptr>::StateId> > currentTransitions = transitions.value(stateIt.key());
       
   390         QHashIterator<XsdTerm::Ptr, QVector<XsdStateMachine<XsdTerm::Ptr>::StateId> > transitionIt(currentTransitions);
       
   391         while (transitionIt.hasNext()) { // iterate over all transitions
       
   392             transitionIt.next();
       
   393 
       
   394             if (transitionIt.value().size() > 1) {
       
   395                 // we have one state with two edges leaving it, that means
       
   396                 // the XsdTerm::Ptr exists twice, that is an error
       
   397                 return false;
       
   398             }
       
   399 
       
   400             QHashIterator<XsdTerm::Ptr, QVector<XsdStateMachine<XsdTerm::Ptr>::StateId> > innerTransitionIt(currentTransitions);
       
   401             while (innerTransitionIt.hasNext()) { // iterate over all transitions again, as we have to compare all transitions with all
       
   402                 innerTransitionIt.next();
       
   403 
       
   404                 if (transitionIt.key() == innerTransitionIt.key()) // do no compare with ourself
       
   405                     continue;
       
   406 
       
   407                 // use the helper method termMatches to check if both term matches
       
   408                 if (termMatches(transitionIt.key(), innerTransitionIt.key(), namePool))
       
   409                     return false;
       
   410             }
       
   411         }
       
   412     }
       
   413 
       
   414     return true;
       
   415 }
       
   416 
       
   417 bool XsdParticleChecker::subsumes(const XsdParticle::Ptr &particle, const XsdParticle::Ptr &derivedParticle, const XsdSchemaContext::Ptr &context, QString &errorMsg)
       
   418 {
       
   419     /**
       
   420      * The algorithm is implemented like described in http://www.ltg.ed.ac.uk/~ht/XML_Europe_2003.html#S2.3
       
   421      */
       
   422 
       
   423     const NamePool::Ptr namePool(context->namePool());
       
   424 
       
   425     XsdStateMachine<XsdTerm::Ptr> baseStateMachine(namePool);
       
   426     XsdStateMachine<XsdTerm::Ptr> derivedStateMachine(namePool);
       
   427 
       
   428     // build up state machines for both particles
       
   429     {
       
   430         XsdStateMachineBuilder builder(&baseStateMachine, namePool);
       
   431         const XsdStateMachine<XsdTerm::Ptr>::StateId endState = builder.reset();
       
   432         const XsdStateMachine<XsdTerm::Ptr>::StateId startState = builder.buildParticle(particle, endState);
       
   433         builder.addStartState(startState);
       
   434 
       
   435         baseStateMachine = baseStateMachine.toDFA();
       
   436     }
       
   437     {
       
   438         XsdStateMachineBuilder builder(&derivedStateMachine, namePool);
       
   439         const XsdStateMachine<XsdTerm::Ptr>::StateId endState = builder.reset();
       
   440         const XsdStateMachine<XsdTerm::Ptr>::StateId startState = builder.buildParticle(derivedParticle, endState);
       
   441         builder.addStartState(startState);
       
   442 
       
   443         derivedStateMachine = derivedStateMachine.toDFA();
       
   444     }
       
   445 
       
   446     QHash<XsdTerm::Ptr, XsdParticle::Ptr> particlesHash = XsdStateMachineBuilder::particleLookupMap(particle);
       
   447     particlesHash.unite(XsdStateMachineBuilder::particleLookupMap(derivedParticle));
       
   448 
       
   449 /*
       
   450     static int counter = 0;
       
   451     {
       
   452         QFile file(QString("/tmp/file_base%1.dot").arg(counter));
       
   453         file.open(QIODevice::WriteOnly);
       
   454         baseStateMachine.outputGraph(&file, QLatin1String("Base"));
       
   455         file.close();
       
   456     }
       
   457     {
       
   458         QFile file(QString("/tmp/file_derived%1.dot").arg(counter));
       
   459         file.open(QIODevice::WriteOnly);
       
   460         derivedStateMachine.outputGraph(&file, QLatin1String("Base"));
       
   461         file.close();
       
   462     }
       
   463     ::system(QString("dot -Tpng /tmp/file_base%1.dot -o/tmp/file_base%1.png").arg(counter).toLatin1().data());
       
   464     ::system(QString("dot -Tpng /tmp/file_derived%1.dot -o/tmp/file_derived%1.png").arg(counter).toLatin1().data());
       
   465 */
       
   466 
       
   467     const XsdStateMachine<XsdTerm::Ptr>::StateId baseStartState = baseStateMachine.startState();
       
   468     const QHash<XsdStateMachine<XsdTerm::Ptr>::StateId, XsdStateMachine<XsdTerm::Ptr>::StateType> baseStates = baseStateMachine.states();
       
   469     const QHash<XsdStateMachine<XsdTerm::Ptr>::StateId, QHash<XsdTerm::Ptr, QVector<XsdStateMachine<XsdTerm::Ptr>::StateId> > > baseTransitions = baseStateMachine.transitions();
       
   470 
       
   471     const XsdStateMachine<XsdTerm::Ptr>::StateId derivedStartState = derivedStateMachine.startState();
       
   472     const QHash<XsdStateMachine<XsdTerm::Ptr>::StateId, XsdStateMachine<XsdTerm::Ptr>::StateType> derivedStates = derivedStateMachine.states();
       
   473     const QHash<XsdStateMachine<XsdTerm::Ptr>::StateId, QHash<XsdTerm::Ptr, QVector<XsdStateMachine<XsdTerm::Ptr>::StateId> > > derivedTransitions = derivedStateMachine.transitions();
       
   474 
       
   475     // @see http://www.ltg.ed.ac.uk/~ht/XML_Europe_2003.html#S2.3.1
       
   476 
       
   477     // define working set
       
   478     QList<QPair<XsdStateMachine<XsdTerm::Ptr>::StateId, XsdStateMachine<XsdTerm::Ptr>::StateId> > workSet;
       
   479     QList<QPair<XsdStateMachine<XsdTerm::Ptr>::StateId, XsdStateMachine<XsdTerm::Ptr>::StateId> > processedSet;
       
   480 
       
   481     // 1) fill working set initially with start states
       
   482     workSet.append(qMakePair<XsdStateMachine<XsdTerm::Ptr>::StateId, XsdStateMachine<XsdTerm::Ptr>::StateId>(baseStartState, derivedStartState));
       
   483     processedSet.append(qMakePair<XsdStateMachine<XsdTerm::Ptr>::StateId, XsdStateMachine<XsdTerm::Ptr>::StateId>(baseStartState, derivedStartState));
       
   484 
       
   485     while (!workSet.isEmpty()) { // while there are state sets to process
       
   486 
       
   487         // 3) dequeue on state set
       
   488         const QPair<XsdStateMachine<XsdTerm::Ptr>::StateId, XsdStateMachine<XsdTerm::Ptr>::StateId> set = workSet.takeFirst();
       
   489 
       
   490         const QHash<XsdTerm::Ptr, QVector<XsdStateMachine<XsdTerm::Ptr>::StateId> > derivedTrans = derivedTransitions.value(set.second);
       
   491         QHashIterator<XsdTerm::Ptr, QVector<XsdStateMachine<XsdTerm::Ptr>::StateId> > derivedIt(derivedTrans);
       
   492 
       
   493         const QHash<XsdTerm::Ptr, QVector<XsdStateMachine<XsdTerm::Ptr>::StateId> > baseTrans = baseTransitions.value(set.first);
       
   494 
       
   495         while (derivedIt.hasNext()) {
       
   496             derivedIt.next();
       
   497 
       
   498             bool found = false;
       
   499             QHashIterator<XsdTerm::Ptr, QVector<XsdStateMachine<XsdTerm::Ptr>::StateId> > baseIt(baseTrans);
       
   500             while (baseIt.hasNext()) {
       
   501                 baseIt.next();
       
   502                 if (derivedTermValid(baseIt.key(), derivedIt.key(), particlesHash, context, errorMsg)) {
       
   503                     const QPair<XsdStateMachine<XsdTerm::Ptr>::StateId, XsdStateMachine<XsdTerm::Ptr>::StateId> endSet =
       
   504                              qMakePair<XsdStateMachine<XsdTerm::Ptr>::StateId, XsdStateMachine<XsdTerm::Ptr>::StateId>(baseIt.value().first(), derivedIt.value().first());
       
   505                     if (!processedSet.contains(endSet) && !workSet.contains(endSet)) {
       
   506                         workSet.append(endSet);
       
   507                         processedSet.append(endSet);
       
   508                     }
       
   509 
       
   510                     found = true;
       
   511                 }
       
   512             }
       
   513 
       
   514             if (!found) {
       
   515                 return false;
       
   516             }
       
   517         }
       
   518     }
       
   519 
       
   520     // 5)
       
   521     QHashIterator<XsdStateMachine<XsdTerm::Ptr>::StateId, XsdStateMachine<XsdTerm::Ptr>::StateType> it(derivedStates);
       
   522     while (it.hasNext()) {
       
   523         it.next();
       
   524 
       
   525         if (it.value() == XsdStateMachine<XsdTerm::Ptr>::EndState || it.value() == XsdStateMachine<XsdTerm::Ptr>::StartEndState) {
       
   526             for (int i = 0; i < processedSet.count(); ++i) {
       
   527                 if (processedSet.at(i).second == it.key() &&
       
   528                     (baseStates.value(processedSet.at(i).first) != XsdStateMachine<XsdTerm::Ptr>::EndState &&
       
   529                      baseStates.value(processedSet.at(i).first) != XsdStateMachine<XsdTerm::Ptr>::StartEndState)) {
       
   530                     errorMsg = QtXmlPatterns::tr("Derived particle allows content that is not allowed in the base particle.");
       
   531                     return false;
       
   532                 }
       
   533             }
       
   534         }
       
   535     }
       
   536 
       
   537     return true;
       
   538 }
       
   539 
       
   540 QT_END_NAMESPACE