C++ List::append方法代码示例

Expression::List TripleContainer::operands() const
{
    Expression::List result;
    result.append(m_operand1);
    result.append(m_operand2);
    result.append(m_operand3);
    return result;
}

Expression::Ptr ExpressionSequence::compress(const StaticContext::Ptr &context)
{
    const Expression::Ptr me(UnlimitedContainer::compress(context));

    if(me != this)
        return me;

    Expression::List::const_iterator it(m_operands.constBegin());
    const Expression::List::const_iterator end(m_operands.constEnd());
    Expression::List result;

    for(; it != end; ++it)
    {
        const ID Id = (*it)->id();

        /* Remove empty sequences. This is rather important because we have some steps in the parser that
         * intentionally, unconditionally and for temporary reasons create expressions like (expr, ()). Of course,
         * empty sequences also occur as part of optimizations.
         *
         * User function call sites that are of type empty-sequence() must be avoided since
         * they may contain calls to fn:error(), which we would rewrite away otherwise. */
        if(Id != IDUserFunctionCallsite && (*it)->staticType()->cardinality().isEmpty())
        {
            /* Rewrite "(1, (), 2)" into "(1, 2)" by not
             * adding (*it) to result. */
            continue;
        }
        else if(Id == IDExpressionSequence)
        {
            /* Rewrite "(1, (2, 3), 4)" into "(1, 2, 3, 4)" */
            Expression::List::const_iterator seqIt((*it)->operands().constBegin());
            const Expression::List::const_iterator seqEnd((*it)->operands().constEnd());

            for(; seqIt != seqEnd; ++seqIt)
                result.append(*seqIt);
        }
        else
            result.append(*it);
    }

    if(result.isEmpty())
        return EmptySequence::create(this, context);
    else if(result.count() == 1)
        return result.first();
    else
    {
        m_operands = result;
        return me;
    }
}

Expression::List PairContainer::operands() const
{
    Expression::List list;
    list.append(m_operand1);
    list.append(m_operand2);
    return list;
}

void Expression::typeCheckOperands(const StaticContext::Ptr &context)
{
    const Expression::List ops(operands());

    /* Check if this expression has any operands at all. */
    if(ops.isEmpty())
        return; /* We're done, early exit. */

    const SequenceType::List opTypes(expectedOperandTypes());
    Expression::List result;

    /* If we create a focus, we handle the last one specially, so avoid it in the loop. */
    const bool createsFocus = has(CreatesFocusForLast);
    const SequenceType::List::const_iterator typeEnd(createsFocus ? --opTypes.constEnd()
                                                                  : opTypes.constEnd());
    const Expression::List::const_iterator end(createsFocus ? --ops.constEnd()
                                                            : ops.constEnd());

    SequenceType::List::const_iterator reqType(opTypes.constBegin());
    SequenceType::Ptr t(*reqType);
    // TODO we assign twice to t here(also below in loop) when ops.size() > 1

    Expression::List::const_iterator it(ops.constBegin());

    for(; it != end; ++it)
    {
        /* This ensures that the last expectedOperandType stays, and is
         * used for all other operands. This is used for expressions that
         * have an infinite amount of operands, such as the concat() function. */
        if(reqType != typeEnd)
        {
            t = *reqType;
            ++reqType;
        }

         /* Let the child & its children typecheck. */
        result.append((*it)->typeCheck(context, t));
    }

    if(createsFocus)
    {
        const StaticContext::Ptr newContext(finalizeStaticContext(context));
        result.append(ops.last()->typeCheck(newContext, opTypes.last()));
    }

    setOperands(result);
}

Expression::Ptr DocumentFN::typeCheck(const StaticContext::Ptr &context,
                                      const SequenceType::Ptr &reqType)
{
    /* See the class documentation for the rewrite that we're doing here. */

    /* Generate type checking code for our operands such that they match. */
    typeCheckOperands(context);

    const QSourceLocation myLocation(context->locationFor(this));
    const FunctionFactory::Ptr functions(context->functionSignatures());

    Expression::Ptr uriSource;

    {
        Expression::List distinctValuesArgs;
        distinctValuesArgs.append(m_operands.first());

        uriSource = functions->createFunctionCall(QXmlName(StandardNamespaces::fn, StandardLocalNames::distinct_values),
                    distinctValuesArgs,
                    context,
                    this);
        context->addLocation(uriSource.data(), myLocation);
    }

    const VariableSlotID rangeSlot = context->allocateRangeSlot();
    const Expression::Ptr uriReference(new RangeVariableReference(uriSource, rangeSlot));
    context->addLocation(uriReference.data(), myLocation);

    Expression::List docArgs;

    if(m_operands.count() == 2)
    {
        Expression::List baseUriArgs;
        baseUriArgs.append(uriReference);
        baseUriArgs.append(m_operands.at(1));

        const Expression::Ptr fnBaseUri(functions->createFunctionCall(QXmlName(StandardNamespaces::fn, StandardLocalNames::resolve_uri),
                                        baseUriArgs,
                                        context,
                                        this));
        context->addLocation(fnBaseUri.data(), myLocation);
        docArgs.append(fnBaseUri);
    }
    else
        docArgs.append(uriReference);

    const Expression::Ptr fnDoc(functions->createFunctionCall(QXmlName(StandardNamespaces::fn, StandardLocalNames::doc),
                                docArgs,
                                context,
                                this));
    context->addLocation(fnDoc.data(), myLocation);


    Expression::Ptr newMe(new ForClause(rangeSlot,
                                        uriSource,
                                        fnDoc,
                                        -1 /* We have no position variable. */));

    Expression::Ptr oldMe(this);
    rewrite(oldMe, newMe, context);
    return newMe->typeCheck(context, reqType);
}

Expression::List SingleContainer::operands() const
{
    Expression::List list;
    list.append(m_operand);
    return list;
}

Expression::Ptr TypeChecker::verifyType(const Expression::Ptr &operand,
                                        const SequenceType::Ptr &reqSeqType,
                                        const StaticContext::Ptr &context,
                                        const ReportContext::ErrorCode code,
                                        const Options options)
{
    const ItemType::Ptr reqType(reqSeqType->itemType());
    const Expression::Properties props(operand->properties());

    /* If operand requires a focus, do the necessary type checking for that. */
    if(props.testFlag(Expression::RequiresFocus) && options.testFlag(CheckFocus))
    {
        const ItemType::Ptr contextType(context->contextItemType());
        if(contextType)
        {
            if(props.testFlag(Expression::RequiresContextItem))
            {
                Q_ASSERT_X(operand->expectedContextItemType(), Q_FUNC_INFO,
                           "When the Expression sets the RequiresContextItem property, it must "
                           "return a type in expectedContextItemType()");
                const ItemType::Ptr expectedContextType(operand->expectedContextItemType());

                /* Allow the empty sequence. We don't want to trigger XPTY0020 on ()/... . */
                if(!expectedContextType->xdtTypeMatches(contextType) && contextType != CommonSequenceTypes::Empty)
                {
                    context->error(wrongType(context->namePool(), operand->expectedContextItemType(), contextType),
                                   ReportContext::XPTY0020, operand.data());
                    return operand;
                }
            }
        }
        else
        {
            context->error(QtXmlPatterns::tr("The focus is undefined."), ReportContext::XPDY0002, operand.data());
            return operand;
        }
    }

    SequenceType::Ptr operandSeqType(operand->staticType());
    ItemType::Ptr operandType(operandSeqType->itemType());

    /* This returns the operand if the types are identical or if operandType
     * is a subtype of reqType. */
    if(reqType->xdtTypeMatches(operandType) || *operandType == *CommonSequenceTypes::Empty)
        return operand;

    /* Since we haven't exited yet, it means that the operandType is a super type
     * of reqType, and that there hence is a path down to it through the
     * type hierachy -- but that doesn't necessarily mean that a up-cast(down the
     * hierarchy) would succeed. */

    Expression::Ptr result(operand);

    if(reqType->isAtomicType())
    {
        const Expression::ID opID = operand->id();
        if((opID == Expression::IDArgumentReference ||
                (opID == Expression::IDCardinalityVerifier && operand->operands().first()->is(Expression::IDArgumentReference)))
                && *BuiltinTypes::item == *operandType)
            return Expression::Ptr(new ArgumentConverter(result, reqType));

        if(!operandType->isAtomicType())
        {
            result = Expression::Ptr(new Atomizer(result));
            /* The atomizer might know more about the type. */
            operandType = result->staticType()->itemType();
        }

        if(reqType->xdtTypeMatches(operandType))
        {
            /* Atomization was sufficient. Either the expected type is xs:anyAtomicType
             * or the type the Atomizer knows it returns, matches the required type. */
            return result;
        }

        const bool compatModeEnabled = context->compatModeEnabled();

        if((options.testFlag(AutomaticallyConvert) && BuiltinTypes::xsUntypedAtomic->xdtTypeMatches(operandType)) ||
                (compatModeEnabled && BuiltinTypes::xsString->xdtTypeMatches(reqType)))
        {
            if(*reqType == *BuiltinTypes::numeric)
            {
                result = typeCheck(new UntypedAtomicConverter(result, BuiltinTypes::xsDouble, code),
                                   context, reqSeqType);
            }
            else
                result = typeCheck(new UntypedAtomicConverter(result, reqType, code), context, reqSeqType);

            /* The UntypedAtomicConverter might know more about the type, so reload. */
            operandType = result->staticType()->itemType();
        }
        else if(compatModeEnabled && *reqType == *BuiltinTypes::xsDouble)
        {
            const FunctionFactory::Ptr functions(context->functionSignatures());
            Expression::List numberArgs;
            numberArgs.append(operand);

            result = functions->createFunctionCall(QXmlName(StandardNamespaces::fn, StandardLocalNames::number),
                                                   numberArgs,
                                                   context,
//.........这里部分代码省略.........

Expression::Ptr Expression::invokeOptimizers(const Expression::Ptr &expr,
                                             const StaticContext::Ptr &context)
{
    Q_ASSERT(expr);

    const OptimizationPass::List opts(expr->optimizationPasses());

    if(opts.isEmpty()) /* Early exit. */
    {
        return expr;
    }

    const OptimizationPass::List::const_iterator passEnd(opts.constEnd());
    const OptimizationPass::List::const_iterator end(opts.constEnd());
    OptimizationPass::List::const_iterator passIt(opts.constBegin());

    for(; passIt != passEnd; ++passIt) /* Invoke each optimization pass. */
    {
        const OptimizationPass::Ptr pass(*passIt); /* Alias, for readability. */
        OptimizationPass::ExpressionMarker sourceMarker(pass->sourceExpression);

        if(pass->startIdentifier && !pass->startIdentifier->matches(expr))
        {
            /* This pass specified a start identifier and it did
             * not match -- let's try the next OptimizationPass. */
            continue;
        }

        const ExpressionIdentifier::List::const_iterator idEnd(pass->operandIdentifiers.constEnd());
        ExpressionIdentifier::List::const_iterator idIt(pass->operandIdentifiers.constBegin());
        const Expression::List ops(expr->operands());
        const Expression::List::const_iterator opEnd(ops.constEnd());
        Expression::List::const_iterator opIt(ops.constBegin());

        switch(pass->operandsMatchMethod)
        {
            case OptimizationPass::Sequential:
            {
                for(; opIt != opEnd; ++opIt)
                {
                    const Expression::Ptr operand(*opIt); /* Alias, for readability. */
                    const ExpressionIdentifier::Ptr opIdentifier(*idIt); /* Alias, for readability. */
                    if(opIdentifier && !opIdentifier->matches(operand))
                    {
                        break;
                    }

                    ++idIt;
                }

                if(opIt == opEnd)
                    break; /* All operands matched, so this pass matched. */
                else
                {
                    /* The loop above did not finish which means all operands did not match.
                       Therefore, this OptimizationPass did not match -- let's try the next one. */
                    continue;
                }
            }
            case OptimizationPass::AnyOrder:
            {
                Q_ASSERT_X(ops.count() == 2, Q_FUNC_INFO,
                           "AnyOrder is currently only supported for Expressions with two operands.");
                if(pass->operandIdentifiers.first()->matches(ops.first()) &&
                   pass->operandIdentifiers.last()->matches(ops.last()))
                {
                    break;
                }
                else if(pass->operandIdentifiers.first()->matches(ops.last()) &&
                        pass->operandIdentifiers.last()->matches(ops.first()))
                {
                    sourceMarker.first() = 1;
                    sourceMarker[1] = 0;
                    break; /* This pass matched. */
                }
                else
                    continue; /* This pass didn't match, let's loop through the next pass. */
            }
        }

        /* Figure out the source Expression, if any. */
        Expression::List operands;
        Expression::Ptr sourceExpr;

        if(!sourceMarker.isEmpty())
        {
            const OptimizationPass::ExpressionMarker::const_iterator mEnd(sourceMarker.constEnd());
            OptimizationPass::ExpressionMarker::const_iterator mIt(sourceMarker.constBegin());
            sourceExpr = expr;

            for(; mIt != mEnd; ++mIt)
            {
                Q_ASSERT(*mIt >= 0);
                sourceExpr = sourceExpr->operands().at(*mIt);
            }

            operands.append(sourceExpr);
        }

        if(operands.isEmpty())
//.........这里部分代码省略.........