qtdeclarative/src/qmlcompiler/qqmljsstoragegeneralizer.cpp

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#include "qqmljsstoragegeneralizer_p.h"

QT_BEGIN_NAMESPACE

/*!
 * \internal
 * \class QQmlJSStorageGeneralizer
 *
 * The QQmlJSStorageGeneralizer is a compile pass that changes all type
 * annotations and the function signature to use a generic storage type like
 * QVariant or QObject*. This is necessary if we cannot rely on the original
 * type to be immediately accessible, for example because we cannot include its
 * header.
 *
 * QQmlJSStorageGeneralizer does not have to use the byte code at all but
 * operates only on the annotations and the function description.
 */

QQmlJSCompilePass::InstructionAnnotations QQmlJSStorageGeneralizer::run(
        InstructionAnnotations annotations, Function *function,
        QQmlJS::DiagnosticMessage *error)
{
    m_error = error;

    if (QQmlJSScope::ConstPtr &returnType = function->returnType) {
        if (QQmlJSScope::ConstPtr stored = m_typeResolver->genericType(
                    returnType, QQmlJSTypeResolver::ComponentIsGeneric::Yes)) {
            returnType = stored;
        } else {
            setError(QStringLiteral("Cannot store the return type %1.")
                     .arg(returnType->internalName(), 0));
            return InstructionAnnotations();
        }
    }

    for (QQmlJSScope::ConstPtr &argument : function->argumentTypes) {
        Q_ASSERT(argument);
        if (QQmlJSScope::ConstPtr stored = m_typeResolver->genericType(
                    argument, QQmlJSTypeResolver::ComponentIsGeneric::Yes)) {
            argument = std::move(stored);
        } else {
            setError(QStringLiteral("Cannot store the argument type %1.")
                     .arg(argument->internalName(), 0));
            return InstructionAnnotations();
        }
    }

    const auto transformRegister = [&](QQmlJSRegisterContent &content, int offset) {
        if (QQmlJSScope::ConstPtr specific = content.storedType()) {
            if (QQmlJSScope::ConstPtr generic = m_typeResolver->genericType(specific)) {
                content = content.storedIn(generic);
            } else {
                setError(QStringLiteral("Cannot store the register type %1.")
                         .arg(specific->internalName()), offset);
                return false;
            }
        }
        return true;
    };

    const auto transformRegisters
            = [&](QFlatMap<int, QQmlJSRegisterContent> &registers, int offset) {
        for (auto j = registers.begin(), jEnd = registers.end(); j != jEnd; ++j) {
            if (!transformRegister(j.value(), offset))
                return false;
        }
        return true;
    };

    for (auto i = annotations.begin(), iEnd = annotations.end(); i != iEnd; ++i) {
        if (!transformRegister(i->second.changedRegister, i.key()))
            return InstructionAnnotations();
        if (!transformRegisters(i->second.typeConversions, i.key()))
            return InstructionAnnotations();
    }

    return annotations;
}

QT_END_NAMESPACE