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    41 

    42 #include "qcardinalityverifier_p.h"

    43 #include "qcommonsequencetypes_p.h"

    44 #include "qemptysequence_p.h"

    45 #include "qsequencemappingiterator_p.h"

    46 

    47 #include "qexpressionsequence_p.h"

    48 

    49 QT_BEGIN_NAMESPACE

    50 

    51 using namespace QPatternist;

    52 

    53 ExpressionSequence::ExpressionSequence(const Expression::List &ops) : UnlimitedContainer(ops)

    54 {

    55     Q_ASSERT_X(1 < ops.count(), Q_FUNC_INFO,

    56                "It makes no sense to have an ExpressionSequence containing less than two expressions.");

    57 }

    58 

    59 Item::Iterator::Ptr ExpressionSequence::mapToSequence(const Expression::Ptr &expr,

    60                                                       const DynamicContext::Ptr &context) const

    61 {

    62     return expr->evaluateSequence(context);

    63 }

    64 

    65 Item::Iterator::Ptr ExpressionSequence::evaluateSequence(const DynamicContext::Ptr &context) const

    66 {

    67     return makeSequenceMappingIterator<Item>(ConstPtr(this),

    68                                              makeListIterator(m_operands),

    69                                              context);

    70 }

    71 

    72 void ExpressionSequence::evaluateToSequenceReceiver(const DynamicContext::Ptr &context) const

    73 {

    74     Expression::List::const_iterator it(m_operands.constBegin());

    75     const Expression::List::const_iterator end(m_operands.constEnd());

    76     Expression::List result;

    77 

    78     for(; it != end; ++it)

    79         (*it)->evaluateToSequenceReceiver(context);

    80 }

    81 

    82 Expression::Ptr ExpressionSequence::compress(const StaticContext::Ptr &context)

    83 {

    84     const Expression::Ptr me(UnlimitedContainer::compress(context));

    85 

    86     if(me != this)

    87         return me;

    88 

    89     Expression::List::const_iterator it(m_operands.constBegin());

    90     const Expression::List::const_iterator end(m_operands.constEnd());

    91     Expression::List result;

    92 

    93     for(; it != end; ++it)

    94     {

    95         const ID Id = (*it)->id();

    96 

    97         /* Remove empty sequences. This is rather important because we have some steps in the parser that

    98          * intentionally, unconditionally and for temporary reasons create expressions like (expr, ()). Of course,

    99          * empty sequences also occur as part of optimizations.

   100          *

   101          * User function call sites that are of type empty-sequence() must be avoided since

   102          * they may contain calls to fn:error(), which we would rewrite away otherwise. */

   103         if(Id != IDUserFunctionCallsite && (*it)->staticType()->cardinality().isEmpty())

   104         {

   105             /* Rewrite "(1, (), 2)" into "(1, 2)" by not

   106              * adding (*it) to result. */

   107             continue;

   108         }

   109         else if(Id == IDExpressionSequence)

   110         {

   111             /* Rewrite "(1, (2, 3), 4)" into "(1, 2, 3, 4)" */

   112             Expression::List::const_iterator seqIt((*it)->operands().constBegin());

   113             const Expression::List::const_iterator seqEnd((*it)->operands().constEnd());

   114 

   115             for(; seqIt != seqEnd; ++seqIt)

   116                 result.append(*seqIt);

   117         }

   118         else

   119             result.append(*it);

   120     }

   121 

   122     if(result.isEmpty())

   123         return EmptySequence::create(this, context);

   124     else if(result.count() == 1)

   125         return result.first();

   126     else

   127     {

   128         m_operands = result;

   129         return me;

   130     }

   131 }

   132 

   133 Expression::Ptr ExpressionSequence::typeCheck(const StaticContext::Ptr &context,

   134                                               const SequenceType::Ptr &reqType)

   135 {

   136     Q_ASSERT(reqType);

   137     Expression::List::iterator it(m_operands.begin());

   138     const Expression::List::iterator end(m_operands.end());

   139 

   140     /* We treat the cardinality differently here by allowing the empty sequence

   141      * for each individual Expression, since the Cardinality can be conformed to by

   142      * the ExpressionSequence as a whole(which we check for at the end). */

   143     const SequenceType::Ptr testOnlyIT(makeGenericSequenceType(reqType->itemType(),

   144                                                                Cardinality::empty() |

   145                                                                reqType->cardinality()));

   146 

   147     for(; it != end; ++it)

   148         *it = (*it)->typeCheck(context, testOnlyIT);

   149 

   150     /* The above loop is only guaranteed to find item type errors, but the cardinality

   151      * can still be wrong since the operands were treated individually. */

   152     return CardinalityVerifier::verifyCardinality(Expression::Ptr(this), reqType->cardinality(), context);

   153 }

   154 

   155 Expression::Properties ExpressionSequence::properties() const

   156 {

   157     const Expression::List::const_iterator end(m_operands.constEnd());

   158     Expression::List::const_iterator it;

   159     bool allEvaled = true;

   160     Expression::Properties props(DisableElimination); /* Why do we have this flag? */

   161 

   162     for(it = m_operands.constBegin(); it != end; ++it)

   163     {

   164         const Expression::Properties newp((*it)->properties());

   165         props |= newp;

   166 

   167         if((newp & IsEvaluated) != IsEvaluated)

   168         {

   169             allEvaled = false;

   170             break;

   171         }

   172     }

   173 

   174     if(!allEvaled)

   175         props &= ~IsEvaluated; /* Remove IsEvaluated. */

   176 

   177     /* One of our children might need the focus, but we don't, so

   178      * cut it out. */

   179     return props & ~RequiresFocus;

   180 }

   181 

   182 SequenceType::Ptr ExpressionSequence::staticType() const

   183 {

   184     return operandsUnionType<ProductOfCardinality>();

   185 }

   186 

   187 SequenceType::List ExpressionSequence::expectedOperandTypes() const

   188 {

   189     SequenceType::List result;

   190     /* ExpressionSequence is a bit strange type wise since it has an

   191      * infinite amount of operands. */

   192     result.append(CommonSequenceTypes::ZeroOrMoreItems);

   193     return result;

   194 }

   195 

   196 ExpressionVisitorResult::Ptr ExpressionSequence::accept(const ExpressionVisitor::Ptr &visitor) const

   197 {

   198     return visitor->visit(this);

   199 }

   200 

   201 Expression::ID ExpressionSequence::id() const

   202 {

   203     return IDExpressionSequence;

   204 }

   205 

   206 QT_END_NAMESPACE