qqmlxmllistmodel.cpp

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// Copyright (C) 2021 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 "qqmlxmllistmodel_p.h"
 
#include <QtQml/qqmlcontext.h>
#include <QtQml/qqmlengine.h>
#include <QtQml/qqmlinfo.h>
#include <QtQml/qqmlfile.h>
 
#include <QtCore/qcoreapplication.h>
#include <QtCore/qfile.h>
#include <QtCore/qfuturewatcher.h>
#include <QtCore/qtimer.h>
#include <QtCore/qxmlstream.h>
 
#if QT_CONFIG(qml_network)
#include <QtNetwork/qnetworkreply.h>
#include <QtNetwork/qnetworkrequest.h>
#endif
 
Q_DECLARE_METATYPE(QQmlXmlListModelQueryResult)
 
QT_BEGIN_NAMESPACE
 
QString QQmlXmlListModelRole::name() const
{
    return m_name;
}
 
void QQmlXmlListModelRole::setName(const QString &name)
{
    if (name == m_name)
        return;
    m_name = name;
    Q_EMIT nameChanged();
}
 
 
 
 
 
QString QQmlXmlListModelRole::elementName() const
{
    return m_elementName;
}
 
void QQmlXmlListModelRole::setElementName(const QString &name)
{
    if (name.startsWith(QLatin1Char('/'))) {
        qmlWarning(this) << tr("An XML element must not start with '/'");
        return;
    } else if (name.endsWith(QLatin1Char('/'))) {
        qmlWarning(this) << tr("An XML element must not end with '/'");
        return;
    } else if (name.contains(QStringLiteral("//"))) {
        qmlWarning(this) << tr("An XML element must not contain \"//\"");
        return;
    }
 
    if (name == m_elementName)
        return;
    m_elementName = name;
    Q_EMIT elementNameChanged();
}
 
QString QQmlXmlListModelRole::attributeName() const
{
    return m_attributeName;
}
 
void QQmlXmlListModelRole::setAttributeName(const QString &attributeName)
{
    if (m_attributeName == attributeName)
        return;
    m_attributeName = attributeName;
    Q_EMIT attributeNameChanged();
}
 
bool QQmlXmlListModelRole::isValid() const
{
    return !m_name.isEmpty();
}
 
QQmlXmlListModel::QQmlXmlListModel(QObject *parent) : QAbstractListModel(parent) { }
 
QQmlXmlListModel::~QQmlXmlListModel()
{
    // Cancel all objects
    for (auto &w : m_watchers.values())
        w->cancel();
    // Wait until all objects are finished
    while (!m_watchers.isEmpty()) {
        auto it = m_watchers.begin();
        it.value()->waitForFinished();
        // Explicitly delete the watcher here, because the connected lambda
        // would not be called until processEvents() is called
        delete it.value();
        m_watchers.erase(it);
    }
}
 
QModelIndex QQmlXmlListModel::index(int row, int column, const QModelIndex &parent) const
{
    return !parent.isValid() && column == 0 && row >= 0 && m_size ? createIndex(row, column)
                                                                  : QModelIndex();
}
 
int QQmlXmlListModel::rowCount(const QModelIndex &parent) const
{
    return !parent.isValid() ? m_size : 0;
}
 
QVariant QQmlXmlListModel::data(const QModelIndex &index, int role) const
{
    const int roleIndex = m_roles.indexOf(role);
    return (roleIndex == -1 || !index.isValid()) ? QVariant()
                                                 : m_data.value(index.row()).value(roleIndex);
}
 
QHash<int, QByteArray> QQmlXmlListModel::roleNames() const
{
    QHash<int, QByteArray> roleNames;
    for (int i = 0; i < m_roles.size(); ++i)
        roleNames.insert(m_roles.at(i), m_roleNames.at(i).toUtf8());
    return roleNames;
}
 
int QQmlXmlListModel::count() const
{
    return m_size;
}
 
QUrl QQmlXmlListModel::source() const
{
    return m_source;
}
 
void QQmlXmlListModel::setSource(const QUrl &src)
{
    if (m_source != src) {
        m_source = src;
        reload();
        Q_EMIT sourceChanged();
    }
}
 
QString QQmlXmlListModel::query() const
{
    return m_query;
}
 
void QQmlXmlListModel::setQuery(const QString &query)
{
    if (!query.startsWith(QLatin1Char('/'))) {
        qmlWarning(this) << QCoreApplication::translate(
                "XmlListModelRoleList", "An XmlListModel query must start with '/'");
        return;
    }
 
    if (m_query != query) {
        m_query = query;
        reload();
        Q_EMIT queryChanged();
    }
}
 
QQmlListProperty<QQmlXmlListModelRole> QQmlXmlListModel::roleObjects()
{
    QQmlListProperty<QQmlXmlListModelRole> list(this, &m_roleObjects);
    list.append = &QQmlXmlListModel::appendRole;
    list.clear = &QQmlXmlListModel::clearRole;
    return list;
}
 
void QQmlXmlListModel::appendRole(QQmlXmlListModelRole *role)
{
    if (role) {
        int i = m_roleObjects.size();
        m_roleObjects.append(role);
        if (m_roleNames.contains(role->name())) {
            qmlWarning(role)
                    << QQmlXmlListModel::tr(
                               "\"%1\" duplicates a previous role name and will be disabled.")
                               .arg(role->name());
            return;
        }
        m_roles.insert(i, m_highestRole);
        m_roleNames.insert(i, role->name());
        ++m_highestRole;
    }
}
 
void QQmlXmlListModel::clearRole()
{
    m_roles.clear();
    m_roleNames.clear();
    m_roleObjects.clear();
}
 
void QQmlXmlListModel::appendRole(QQmlListProperty<QQmlXmlListModelRole> *list,
                                  QQmlXmlListModelRole *role)
{
    auto object = qobject_cast<QQmlXmlListModel *>(list->object);
    if (object) // role is checked inside appendRole
        object->appendRole(role);
}
 
void QQmlXmlListModel::clearRole(QQmlListProperty<QQmlXmlListModelRole> *list)
{
    auto object = qobject_cast<QQmlXmlListModel *>(list->object);
    if (object)
        object->clearRole();
}
 
void QQmlXmlListModel::tryExecuteQuery(const QByteArray &data)
{
    auto job = createJob(data);
    m_queryId = job.queryId;
    QQmlXmlListModelQueryRunnable *runnable = new QQmlXmlListModelQueryRunnable(std::move(job));
    if (runnable) {
        auto future = runnable->future();
        auto *watcher = new ResultFutureWatcher();
        // No need to connect to canceled signal, because it just notifies that
        // QFuture::cancel() was called. We will get the finished() signal in
        // both cases.
        connect(watcher, &ResultFutureWatcher::finished, this, [id = m_queryId, this]() {
            auto *watcher = static_cast<ResultFutureWatcher *>(sender());
            if (watcher) {
                if (!watcher->isCanceled()) {
                    QQmlXmlListModelQueryResult result = watcher->result();
                    // handle errors
                    for (const auto &errorInfo : result.errors)
                        queryError(errorInfo.first, errorInfo.second);
                    // fill results
                    queryCompleted(result);
                }
                // remove from watchers
                m_watchers.remove(id);
                watcher->deleteLater();
            }
        });
        m_watchers[m_queryId] = watcher;
        watcher->setFuture(future);
        QThreadPool::globalInstance()->start(runnable);
    } else {
        m_errorString = tr("Failed to create an instance of QRunnable query object");
        m_status = QQmlXmlListModel::Error;
        m_queryId = -1;
        Q_EMIT statusChanged(m_status);
    }
}
 
QQmlXmlListModelQueryJob QQmlXmlListModel::createJob(const QByteArray &data)
{
    QQmlXmlListModelQueryJob job;
    job.queryId = nextQueryId();
    job.data = data;
    job.query = m_query;
 
    for (int i = 0; i < m_roleObjects.size(); i++) {
        if (!m_roleObjects.at(i)->isValid()) {
            job.roleNames << QString();
            job.elementNames << QString();
            job.elementAttributes << QString();
            continue;
        }
        job.roleNames << m_roleObjects.at(i)->name();
        job.elementNames << m_roleObjects.at(i)->elementName();
        job.elementAttributes << m_roleObjects.at(i)->attributeName();
        job.roleQueryErrorId << static_cast<void *>(m_roleObjects.at(i));
    }
 
    return job;
}
 
int QQmlXmlListModel::nextQueryId()
{
    m_nextQueryIdGenerator++;
    if (m_nextQueryIdGenerator <= 0)
        m_nextQueryIdGenerator = 1;
    return m_nextQueryIdGenerator;
}
 
QQmlXmlListModel::Status QQmlXmlListModel::status() const
{
    return m_status;
}
 
qreal QQmlXmlListModel::progress() const
{
    return m_progress;
}
 
QString QQmlXmlListModel::errorString() const
{
    return m_errorString;
}
 
void QQmlXmlListModel::classBegin()
{
    m_isComponentComplete = false;
}
 
void QQmlXmlListModel::componentComplete()
{
    m_isComponentComplete = true;
    reload();
}
 
void QQmlXmlListModel::reload()
{
    if (!m_isComponentComplete)
        return;
 
    if (m_queryId > 0 && m_watchers.contains(m_queryId))
        m_watchers[m_queryId]->cancel();
 
    m_queryId = -1;
 
    if (m_size < 0)
        m_size = 0;
 
#if QT_CONFIG(qml_network)
    if (m_reply) {
        m_reply->abort();
        deleteReply();
    }
#endif
 
    const QQmlContext *context = qmlContext(this);
    const auto resolvedSource = context ? context->resolvedUrl(m_source) : m_source;
 
    if (resolvedSource.isEmpty()) {
        m_queryId = 0;
        notifyQueryStarted(false);
        QTimer::singleShot(0, this, &QQmlXmlListModel::dataCleared);
    } else if (QQmlFile::isLocalFile(resolvedSource)) {
        QFile file(QQmlFile::urlToLocalFileOrQrc(resolvedSource));
        const bool opened = file.open(QIODevice::ReadOnly);
        if (!opened)
            qWarning("Failed to open file %s: %s", qPrintable(file.fileName()),
                     qPrintable(file.errorString()));
        QByteArray data = opened ? file.readAll() : QByteArray();
        notifyQueryStarted(false);
        if (data.isEmpty()) {
            m_queryId = 0;
            QTimer::singleShot(0, this, &QQmlXmlListModel::dataCleared);
        } else {
            tryExecuteQuery(data);
        }
    } else {
#if QT_CONFIG(qml_network)
        notifyQueryStarted(true);
        QNetworkRequest req(resolvedSource);
        req.setRawHeader("Accept", "application/xml,*/*");
        m_reply = qmlContext(this)->engine()->networkAccessManager()->get(req);
 
        QObject::connect(m_reply, &QNetworkReply::finished, this,
                         &QQmlXmlListModel::requestFinished);
        QObject::connect(m_reply, &QNetworkReply::downloadProgress, this,
                         &QQmlXmlListModel::requestProgress);
#else
        m_queryId = 0;
        notifyQueryStarted(false);
        QTimer::singleShot(0, this, &QQmlXmlListModel::dataCleared);
#endif
    }
}
 
#if QT_CONFIG(qml_network)
void QQmlXmlListModel::requestFinished()
{
    if (m_reply->error() != QNetworkReply::NoError) {
        m_errorString = m_reply->errorString();
        deleteReply();
 
        if (m_size > 0) {
            beginRemoveRows(QModelIndex(), 0, m_size - 1);
            m_data.clear();
            m_size = 0;
            endRemoveRows();
            Q_EMIT countChanged();
        }
 
        m_status = Error;
        m_queryId = -1;
        Q_EMIT statusChanged(m_status);
    } else {
        QByteArray data = m_reply->readAll();
        if (data.isEmpty()) {
            m_queryId = 0;
            QTimer::singleShot(0, this, &QQmlXmlListModel::dataCleared);
        } else {
            tryExecuteQuery(data);
        }
        deleteReply();
 
        m_progress = 1.0;
        Q_EMIT progressChanged(m_progress);
    }
}
 
void QQmlXmlListModel::deleteReply()
{
    if (m_reply) {
        QObject::disconnect(m_reply, 0, this, 0);
        m_reply->deleteLater();
        m_reply = nullptr;
    }
}
#endif
 
void QQmlXmlListModel::requestProgress(qint64 received, qint64 total)
{
    if (m_status == Loading && total > 0) {
        m_progress = qreal(received) / total;
        Q_EMIT progressChanged(m_progress);
    }
}
 
void QQmlXmlListModel::dataCleared()
{
    QQmlXmlListModelQueryResult r;
    r.queryId = 0;
    queryCompleted(r);
}
 
void QQmlXmlListModel::queryError(void *object, const QString &error)
{
    for (int i = 0; i < m_roleObjects.size(); i++) {
        if (m_roleObjects.at(i) == static_cast<QQmlXmlListModelRole *>(object)) {
            qmlWarning(m_roleObjects.at(i))
                    << QQmlXmlListModel::tr("Query error: \"%1\"").arg(error);
            return;
        }
    }
    qmlWarning(this) << QQmlXmlListModel::tr("Query error: \"%1\"").arg(error);
}
 
void QQmlXmlListModel::queryCompleted(const QQmlXmlListModelQueryResult &result)
{
    if (result.queryId != m_queryId)
        return;
 
    int origCount = m_size;
    bool sizeChanged = result.data.size() != m_size;
 
    if (m_source.isEmpty())
        m_status = Null;
    else
        m_status = Ready;
    m_errorString.clear();
    m_queryId = -1;
 
    if (origCount > 0) {
        beginRemoveRows(QModelIndex(), 0, origCount - 1);
        endRemoveRows();
    }
    m_size = result.data.size();
    m_data = result.data;
 
    if (m_size > 0) {
        beginInsertRows(QModelIndex(), 0, m_size - 1);
        endInsertRows();
    }
 
    if (sizeChanged)
        Q_EMIT countChanged();
 
    Q_EMIT statusChanged(m_status);
}
 
void QQmlXmlListModel::notifyQueryStarted(bool remoteSource)
{
    m_progress = remoteSource ? 0.0 : 1.0;
    m_status = QQmlXmlListModel::Loading;
    m_errorString.clear();
    Q_EMIT progressChanged(m_progress);
    Q_EMIT statusChanged(m_status);
}
 
static qsizetype findIndexOfName(const QStringList &elementNames, const QStringView &name,
                                 qsizetype startIndex = 0)
{
    for (auto idx = startIndex; idx < elementNames.size(); ++idx) {
        if (elementNames[idx].startsWith(name))
            return idx;
    }
    return -1;
}
 
QQmlXmlListModelQueryRunnable::QQmlXmlListModelQueryRunnable(QQmlXmlListModelQueryJob &&job)
    : m_job(std::move(job))
{
    setAutoDelete(true);
}
 
void QQmlXmlListModelQueryRunnable::run()
{
    m_promise.start();
    if (!m_promise.isCanceled()) {
        QQmlXmlListModelQueryResult result;
        result.queryId = m_job.queryId;
        doQueryJob(&result);
        m_promise.addResult(std::move(result));
    }
    m_promise.finish();
}
 
QFuture<QQmlXmlListModelQueryResult> QQmlXmlListModelQueryRunnable::future() const
{
    return m_promise.future();
}
 
void QQmlXmlListModelQueryRunnable::doQueryJob(QQmlXmlListModelQueryResult *currentResult)
{
    Q_ASSERT(m_job.queryId != -1);
 
    QByteArray data(m_job.data);
    QXmlStreamReader reader;
    reader.addData(data);
 
    QStringList items = m_job.query.split(QLatin1Char('/'), Qt::SkipEmptyParts);
 
    while (!reader.atEnd() && !m_promise.isCanceled()) {
        int i = 0;
        while (i < items.size()) {
            if (reader.readNextStartElement()) {
                if (reader.name() == items.at(i)) {
                    if (i != items.size() - 1) {
                        i++;
                        continue;
                    } else {
                        processElement(currentResult, items.at(i), reader);
                    }
                } else {
                    reader.skipCurrentElement();
                }
            }
            if (reader.tokenType() == QXmlStreamReader::Invalid) {
                reader.readNext();
                break;
            } else if (reader.hasError()) {
                reader.raiseError();
                break;
            }
        }
    }
}
 
void QQmlXmlListModelQueryRunnable::processElement(QQmlXmlListModelQueryResult *currentResult,
                                                   const QString &element, QXmlStreamReader &reader)
{
    if (!reader.isStartElement() || reader.name() != element)
        return;
 
    const QStringList &elementNames = m_job.elementNames;
    const QStringList &attributes = m_job.elementAttributes;
    QFlatMap<int, QString> results;
 
    // First of all check all the empty element names. They might have
    // attributes to be read from the current element
    if (!reader.attributes().isEmpty()) {
        for (auto index = 0; index < elementNames.size(); ++index) {
            if (elementNames.at(index).isEmpty() && !attributes.at(index).isEmpty()) {
                const QString &attribute = attributes.at(index);
                if (reader.attributes().hasAttribute(attribute))
                    results[index] = reader.attributes().value(attribute).toString();
            }
        }
    }
 
    // After that we recursively search for the elements, considering that we
    // can have nested element names in our model, and that the same element
    // can be used multiple types (with different attributes, for example)
    readSubTree(QString(), reader, results, &currentResult->errors);
 
    if (reader.hasError())
        currentResult->errors.push_back(qMakePair(this, reader.errorString()));
 
    currentResult->data << results;
}
 
void QQmlXmlListModelQueryRunnable::readSubTree(const QString &prefix, QXmlStreamReader &reader,
                                                QFlatMap<int, QString> &results,
                                                QList<QPair<void *, QString>> *errors)
{
    const QStringList &elementNames = m_job.elementNames;
    const QStringList &attributes = m_job.elementAttributes;
    while (reader.readNextStartElement()) {
        const auto name = reader.name();
        const QString fullName =
                prefix.isEmpty() ? name.toString() : (prefix + QLatin1Char('/') + name.toString());
        qsizetype index = name.isEmpty() ? -1 : findIndexOfName(elementNames, fullName);
        if (index >= 0) {
            // We can have multiple roles with the same element name, but
            // different attributes, so we need to cache the attributes and
            // element text.
            const auto elementAttributes = reader.attributes();
            // We can read text only when the element actually contains it,
            // otherwise it will be an error. It can also be used to check that
            // we've reached the bottom level.
            QString elementText;
            bool elementTextRead = false;
            while (index >= 0) {
                // if the path matches completely, not just starts with, we
                // need to actually extract value
                if (elementNames[index] == fullName) {
                    QString roleResult;
                    const QString &attribute = attributes.at(index);
                    if (!attribute.isEmpty()) {
                        if (elementAttributes.hasAttribute(attribute)) {
                            roleResult = elementAttributes.value(attributes.at(index)).toString();
                        } else {
                            errors->push_back(qMakePair(m_job.roleQueryErrorId.at(index),
                                                        QLatin1String("Attribute %1 not found")
                                                                .arg(attributes[index])));
                        }
                    } else if (!elementNames.at(index).isEmpty()) {
                        if (!elementTextRead) {
                            elementText =
                                    reader.readElementText(QXmlStreamReader::IncludeChildElements);
                            elementTextRead = true;
                        }
                        roleResult = elementText;
                    }
                    results[index] = roleResult;
                }
                // search for the next role with the same element name
                index = findIndexOfName(elementNames, fullName, index + 1);
            }
            if (!elementTextRead)
                readSubTree(fullName, reader, results, errors);
        } else {
            reader.skipCurrentElement();
        }
    }
}
 
QT_END_NAMESPACE
 
#include "moc_qqmlxmllistmodel_p.cpp"