qqmlincubator.cpp

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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#include "qqmlincubator.h"
#include "qqmlcomponent.h"
#include "qqmlincubator_p.h"
 
#include "qqmlobjectcreator_p.h"
#include <private/qqmlcomponent_p.h>
 
void QQmlEnginePrivate::incubate(
        QQmlIncubator &i, const QQmlRefPointer<QQmlContextData> &forContext)
{
    QExplicitlySharedDataPointer<QQmlIncubatorPrivate> p(i.d);
 
    QQmlIncubator::IncubationMode mode = i.incubationMode();
 
    if (!incubationController)
        mode = QQmlIncubator::Synchronous;
 
    if (mode == QQmlIncubator::AsynchronousIfNested) {
        mode = QQmlIncubator::Synchronous;
 
        // Need to find the first constructing context and see if it is asynchronous
        QExplicitlySharedDataPointer<QQmlIncubatorPrivate> parentIncubator;
        QQmlRefPointer<QQmlContextData> cctxt = forContext;
        while (cctxt) {
            if (QQmlIncubatorPrivate *incubator = cctxt->incubator()) {
                parentIncubator = incubator;
                break;
            }
            cctxt = cctxt->parent();
        }
 
        if (parentIncubator && parentIncubator->isAsynchronous) {
            mode = QQmlIncubator::Asynchronous;
            p->waitingOnMe = parentIncubator;
            parentIncubator->waitingFor.insert(p.data());
        }
    }
 
    p->isAsynchronous = (mode != QQmlIncubator::Synchronous);
 
    inProgressCreations++;
 
    if (mode == QQmlIncubator::Synchronous) {
        QRecursionWatcher<QQmlIncubatorPrivate, &QQmlIncubatorPrivate::recursion> watcher(p.data());
 
        p->changeStatus(QQmlIncubator::Loading);
 
        if (!watcher.hasRecursed()) {
            QQmlInstantiationInterrupt i;
            p->incubate(i);
        }
    } else {
        incubatorList.insert(p.data());
        incubatorCount++;
 
        p->vmeGuard.guard(p->creator.data());
        p->changeStatus(QQmlIncubator::Loading);
 
        if (incubationController)
             incubationController->incubatingObjectCountChanged(incubatorCount);
    }
}
 
void QQmlEngine::setIncubationController(QQmlIncubationController *controller)
{
    Q_D(QQmlEngine);
    if (d->incubationController)
        d->incubationController->d = nullptr;
    d->incubationController = controller;
    if (controller) controller->d = d;
}
 
QQmlIncubationController *QQmlEngine::incubationController() const
{
    Q_D(const QQmlEngine);
    return d->incubationController;
}
 
QQmlIncubatorPrivate::QQmlIncubatorPrivate(QQmlIncubator *q, QQmlIncubator::IncubationMode m)
    : q(q), status(QQmlIncubator::Null), mode(m), isAsynchronous(false), progress(Execute),
      result(nullptr), enginePriv(nullptr), waitingOnMe(nullptr)
{
}
 
QQmlIncubatorPrivate::~QQmlIncubatorPrivate()
{
    clear();
}
 
void QQmlIncubatorPrivate::clear()
{
    // reset the tagged pointer
    if (requiredPropertiesFromComponent)
        requiredPropertiesFromComponent = decltype(requiredPropertiesFromComponent){};
    compilationUnit.reset();
    if (next.isInList()) {
        next.remove();
        enginePriv->incubatorCount--;
        QQmlIncubationController *controller = enginePriv->incubationController;
        if (controller)
             controller->incubatingObjectCountChanged(enginePriv->incubatorCount);
    }
    enginePriv = nullptr;
    if (!rootContext.isNull()) {
        if (rootContext->incubator())
            rootContext->setIncubator(nullptr);
        rootContext.setContextData({});
    }
 
    if (nextWaitingFor.isInList()) {
        Q_ASSERT(waitingOnMe);
        nextWaitingFor.remove();
        waitingOnMe = nullptr;
    }
 
    // if we're waiting on any incubators then they should be cleared too.
    while (waitingFor.first()) {
        QQmlIncubator * i = static_cast<QQmlIncubatorPrivate*>(waitingFor.first())->q;
        if (i)
            i->clear();
    }
 
    bool guardOk = vmeGuard.isOK();
 
    vmeGuard.clear();
    if (creator && guardOk)
        creator->clear();
    creator.reset(nullptr);
}
 
QQmlIncubationController::QQmlIncubationController()
: d(nullptr)
{
}
 
QQmlIncubationController::~QQmlIncubationController()
{
    if (d) QQmlEnginePrivate::get(d)->setIncubationController(nullptr);
    d = nullptr;
}
 
QQmlEngine *QQmlIncubationController::engine() const
{
    return QQmlEnginePrivate::get(d);
}
 
int QQmlIncubationController::incubatingObjectCount() const
{
    return d ? d->incubatorCount : 0;
}
 
void QQmlIncubationController::incubatingObjectCountChanged(int incubatingObjectCount)
{
    Q_UNUSED(incubatingObjectCount);
}
 
void QQmlIncubatorPrivate::forceCompletion(QQmlInstantiationInterrupt &i)
{
    while (QQmlIncubator::Loading == status) {
        while (QQmlIncubator::Loading == status && !waitingFor.isEmpty())
            waitingFor.first()->forceCompletion(i);
        if (QQmlIncubator::Loading == status)
            incubate(i);
    }
}
 
 
void QQmlIncubatorPrivate::incubate(QQmlInstantiationInterrupt &i)
{
    if (!compilationUnit)
        return;
 
    QExplicitlySharedDataPointer<QQmlIncubatorPrivate> protectThis(this);
 
    QRecursionWatcher<QQmlIncubatorPrivate, &QQmlIncubatorPrivate::recursion> watcher(this);
    // get a copy of the engine pointer as it might get reset;
    QQmlEnginePrivate *enginePriv = this->enginePriv;
 
    // Incubating objects takes quite a bit more stack space than our usual V4 function
    enum { EstimatedSizeInV4Frames = 2 };
    QV4::ExecutionEngineCallDepthRecorder<EstimatedSizeInV4Frames> callDepthRecorder(
                compilationUnit->engine);
    if (callDepthRecorder.hasOverflow()) {
        QQmlError error;
        error.setMessageType(QtCriticalMsg);
        error.setUrl(compilationUnit->url());
        error.setDescription(QQmlComponent::tr("Maximum call stack size exceeded."));
        errors << error;
        progress = QQmlIncubatorPrivate::Completed;
        goto finishIncubate;
    }
 
    if (!vmeGuard.isOK()) {
        QQmlError error;
        error.setMessageType(QtInfoMsg);
        error.setUrl(compilationUnit->url());
        error.setDescription(QQmlComponent::tr("Object or context destroyed during incubation"));
        errors << error;
        progress = QQmlIncubatorPrivate::Completed;
 
        goto finishIncubate;
    }
 
    vmeGuard.clear();
 
    if (progress == QQmlIncubatorPrivate::Execute) {
        enginePriv->referenceScarceResources();
        QObject *tresult = nullptr;
        tresult = creator->create(subComponentToCreate, /*parent*/nullptr, &i);
        if (!tresult)
            errors = creator->errors;
        else {
           RequiredProperties* requiredProperties = creator->requiredProperties();
           for (auto it = initialProperties.cbegin(); it != initialProperties.cend(); ++it) {
               auto component = tresult;
               auto name = it.key();
               QQmlProperty prop = QQmlComponentPrivate::removePropertyFromRequired(
                           component, name, requiredProperties, QQmlEnginePrivate::get(enginePriv));
               if (!prop.isValid() || !prop.write(it.value())) {
                   QQmlError error{};
                   error.setUrl(compilationUnit->url());
                   error.setDescription(QLatin1String("Could not set property %1").arg(name));
                   errors.push_back(error);
               }
           }
        }
        enginePriv->dereferenceScarceResources();
 
        if (watcher.hasRecursed())
            return;
 
        result = tresult;
        if (errors.isEmpty() && result == nullptr)
            goto finishIncubate;
 
        if (result) {
            QQmlData *ddata = QQmlData::get(result);
            Q_ASSERT(ddata);
            //see QQmlComponent::beginCreate for explanation of indestructible
            ddata->indestructible = true;
            ddata->explicitIndestructibleSet = true;
            ddata->rootObjectInCreation = false;
            if (q) {
                q->setInitialState(result);
                if (creator && !creator->requiredProperties()->empty()) {
                    const RequiredProperties *unsetRequiredProperties = creator->requiredProperties();
                    for (const auto& unsetRequiredProperty: *unsetRequiredProperties)
                        errors << QQmlComponentPrivate::unsetRequiredPropertyToQQmlError(unsetRequiredProperty);
                }
            }
        }
 
        if (watcher.hasRecursed())
            return;
 
        if (errors.isEmpty())
            progress = QQmlIncubatorPrivate::Completing;
        else
            progress = QQmlIncubatorPrivate::Completed;
 
        changeStatus(calculateStatus());
 
        if (watcher.hasRecursed())
            return;
 
        if (i.shouldInterrupt())
            goto finishIncubate;
    }
 
    if (progress == QQmlIncubatorPrivate::Completing) {
        do {
            if (watcher.hasRecursed())
                return;
 
            if (creator->finalize(i)) {
                rootContext = creator->rootContext();
                progress = QQmlIncubatorPrivate::Completed;
                goto finishIncubate;
            }
        } while (!i.shouldInterrupt());
    }
 
finishIncubate:
    if (progress == QQmlIncubatorPrivate::Completed && waitingFor.isEmpty()) {
        QExplicitlySharedDataPointer<QQmlIncubatorPrivate> isWaiting = waitingOnMe;
        clear();
 
        if (isWaiting) {
            QRecursionWatcher<QQmlIncubatorPrivate, &QQmlIncubatorPrivate::recursion> watcher(isWaiting.data());
            changeStatus(calculateStatus());
            if (!watcher.hasRecursed())
                isWaiting->incubate(i);
        } else {
            changeStatus(calculateStatus());
        }
 
        enginePriv->inProgressCreations--;
 
        if (0 == enginePriv->inProgressCreations) {
            while (enginePriv->erroredBindings)
                enginePriv->warning(enginePriv->erroredBindings->removeError());
        }
    } else if (!creator.isNull()) {
        vmeGuard.guard(creator.data());
    }
}
 
void QQmlIncubatorPrivate::incubateCppBasedComponent(QQmlComponent *component, QQmlContext *context)
{
    auto compPriv = QQmlComponentPrivate::get(component);
    Q_ASSERT(compPriv->loadedType.isCreatable());
    std::unique_ptr<QObject> object(component->beginCreate(context));
    component->setInitialProperties(object.get(), initialProperties);
    if (auto props = compPriv->state.requiredProperties()) {
        requiredPropertiesFromComponent = props;
        requiredPropertiesFromComponent.setTag(HadTopLevelRequired::Yes);
    }
    q->setInitialState(object.get());
    if (requiredPropertiesFromComponent && !requiredPropertiesFromComponent->isEmpty()) {
        for (const RequiredPropertyInfo &unsetRequiredProperty :
             std::as_const(*requiredPropertiesFromComponent)) {
            errors << QQmlComponentPrivate::unsetRequiredPropertyToQQmlError(unsetRequiredProperty);
        }
    } else {
        compPriv->completeCreate();
        result = object.release();
        progress = QQmlIncubatorPrivate::Completed;
    }
    changeStatus(calculateStatus());
 
}
 
void QQmlIncubationController::incubateFor(int msecs)
{
    if (!d || !d->incubatorCount)
        return;
 
    QDeadlineTimer deadline(msecs);
    QQmlInstantiationInterrupt i(deadline);
    do {
        static_cast<QQmlIncubatorPrivate*>(d->incubatorList.first())->incubate(i);
    } while (d && d->incubatorCount != 0 && !i.shouldInterrupt());
}
 
void QQmlIncubationController::incubateWhile(std::atomic<bool> *flag, int msecs)
{
    if (!d || !d->incubatorCount)
        return;
 
    QQmlInstantiationInterrupt i(flag, msecs ? QDeadlineTimer(msecs) : QDeadlineTimer::Forever);
    do {
        static_cast<QQmlIncubatorPrivate*>(d->incubatorList.first())->incubate(i);
    } while (d && d->incubatorCount != 0 && !i.shouldInterrupt());
}
 
QQmlIncubator::QQmlIncubator(IncubationMode mode)
    : d(new QQmlIncubatorPrivate(this, mode))
{
    d->ref.ref();
}
 
QQmlIncubator::~QQmlIncubator()
{
    d->q = nullptr;
 
    if (!d->ref.deref()) {
        delete d;
    }
    d = nullptr;
}
 
void QQmlIncubator::clear()
{
    QRecursionWatcher<QQmlIncubatorPrivate, &QQmlIncubatorPrivate::recursion> watcher(d);
 
    Status s = status();
 
    if (s == Null)
        return;
 
    QQmlEnginePrivate *enginePriv = d->enginePriv;
    if (s == Loading) {
        Q_ASSERT(d->compilationUnit);
        if (d->result) d->result->deleteLater();
        d->result = nullptr;
    }
 
    d->clear();
 
    Q_ASSERT(d->compilationUnit.isNull());
    Q_ASSERT(d->waitingOnMe.data() == nullptr);
    Q_ASSERT(d->waitingFor.isEmpty());
 
    d->errors.clear();
    d->progress = QQmlIncubatorPrivate::Execute;
    d->result = nullptr;
 
    if (s == Loading) {
        Q_ASSERT(enginePriv);
 
        enginePriv->inProgressCreations--;
        if (0 == enginePriv->inProgressCreations) {
            while (enginePriv->erroredBindings)
                enginePriv->warning(enginePriv->erroredBindings->removeError());
        }
    }
 
    d->changeStatus(Null);
}
 
void QQmlIncubator::forceCompletion()
{
    QQmlInstantiationInterrupt i;
    d->forceCompletion(i);
}
 
bool QQmlIncubator::isNull() const
{
    return status() == Null;
}
 
bool QQmlIncubator::isReady() const
{
    return status() == Ready;
}
 
bool QQmlIncubator::isError() const
{
    return status() == Error;
}
 
bool QQmlIncubator::isLoading() const
{
    return status() == Loading;
}
 
QList<QQmlError> QQmlIncubator::errors() const
{
    return d->errors;
}
 
QQmlIncubator::IncubationMode QQmlIncubator::incubationMode() const
{
    return d->mode;
}
 
QQmlIncubator::Status QQmlIncubator::status() const
{
    return d->status;
}
 
QObject *QQmlIncubator::object() const
{
    if (status() != Ready)
        return nullptr;
    else
        return d->result;
}
 
RequiredProperties *QQmlIncubatorPrivate::requiredProperties()
{
    if (creator)
        return creator->requiredProperties();
    else
        return requiredPropertiesFromComponent.data();
}
 
bool QQmlIncubatorPrivate::hadTopLevelRequiredProperties() const
{
    if (creator)
        return creator->componentHadTopLevelRequiredProperties();
    else
        return requiredPropertiesFromComponent.tag() == HadTopLevelRequired::Yes;
}
 
void QQmlIncubator::setInitialProperties(const QVariantMap &initialProperties)
{
    d->initialProperties = initialProperties;
}
 
void QQmlIncubator::statusChanged(Status status)
{
    Q_UNUSED(status);
}
 
void QQmlIncubator::setInitialState(QObject *object)
{
    Q_UNUSED(object);
}
 
void QQmlIncubatorPrivate::changeStatus(QQmlIncubator::Status s)
{
    if (s == status)
        return;
 
    status = s;
    if (q)
        q->statusChanged(status);
}
 
QQmlIncubator::Status QQmlIncubatorPrivate::calculateStatus() const
{
    if (!errors.isEmpty())
        return QQmlIncubator::Error;
    else if (result && progress == QQmlIncubatorPrivate::Completed && waitingFor.isEmpty())
        return QQmlIncubator::Ready;
    else if (compilationUnit)
        return QQmlIncubator::Loading;
    else
        return QQmlIncubator::Null;
}