qqmltypeloader.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 <private/qqmltypeloader_p.h>
 
#include <private/qqmldirdata_p.h>
#include <private/qqmlprofiler_p.h>
#include <private/qqmlscriptblob_p.h>
#include <private/qqmltypedata_p.h>
#include <private/qqmltypeloaderqmldircontent_p.h>
#include <private/qqmltypeloaderthread_p.h>
#include <private/qqmlsourcecoordinate_p.h>
 
#include <QtQml/qqmlabstracturlinterceptor.h>
#include <QtQml/qqmlengine.h>
#include <QtQml/qqmlextensioninterface.h>
#include <QtQml/qqmlfile.h>
 
#include <qtqml_tracepoints_p.h>
 
#include <QtCore/qdir.h>
#include <QtCore/qdiriterator.h>
#include <QtCore/qfile.h>
#include <QtCore/qthread.h>
 
#include <functional>
 
// #define DATABLOB_DEBUG
#ifdef DATABLOB_DEBUG
#define ASSERT_LOADTHREAD() do { if (!m_thread->isThisThread()) qFatal("QQmlTypeLoader: Caller not in load thread"); } while (false)
#else
#define ASSERT_LOADTHREAD()
#endif
 
 
QT_BEGIN_NAMESPACE
 
namespace {
 
    template<typename LockType>
    struct LockHolder
    {
        LockType& lock;
        LockHolder(LockType *l) : lock(*l) { lock.lock(); }
        ~LockHolder() { lock.unlock(); }
    };
}
 
Q_TRACE_POINT(qtqml, QQmlCompiling_entry, const QUrl &url)
Q_TRACE_POINT(qtqml, QQmlCompiling_exit)
 
 
void QQmlTypeLoader::invalidate()
{
    if (m_thread) {
        shutdownThread();
        delete m_thread;
        m_thread = nullptr;
    }
 
#if QT_CONFIG(qml_network)
    // Need to delete the network replies after
    // the loader thread is shutdown as it could be
    // getting new replies while we clear them
    m_networkReplies.clear();
#endif // qml_network
}
 
#if QT_CONFIG(qml_debug)
void QQmlTypeLoader::setProfiler(QQmlProfiler *profiler)
{
    Q_ASSERT(!m_profiler);
    m_profiler.reset(profiler);
}
#endif
 
struct PlainLoader {
    void loadThread(QQmlTypeLoader *loader, QQmlDataBlob *blob) const
    {
        loader->loadThread(blob);
    }
    void load(QQmlTypeLoader *loader, QQmlDataBlob *blob) const
    {
        loader->m_thread->load(blob);
    }
    void loadAsync(QQmlTypeLoader *loader, QQmlDataBlob *blob) const
    {
        loader->m_thread->loadAsync(blob);
    }
};
 
struct StaticLoader {
    const QByteArray &data;
    StaticLoader(const QByteArray &data) : data(data) {}
 
    void loadThread(QQmlTypeLoader *loader, QQmlDataBlob *blob) const
    {
        loader->loadWithStaticDataThread(blob, data);
    }
    void load(QQmlTypeLoader *loader, QQmlDataBlob *blob) const
    {
        loader->m_thread->loadWithStaticData(blob, data);
    }
    void loadAsync(QQmlTypeLoader *loader, QQmlDataBlob *blob) const
    {
        loader->m_thread->loadWithStaticDataAsync(blob, data);
    }
};
 
struct CachedLoader {
    const QQmlPrivate::CachedQmlUnit *unit;
    CachedLoader(const QQmlPrivate::CachedQmlUnit *unit) :  unit(unit) {}
 
    void loadThread(QQmlTypeLoader *loader, QQmlDataBlob *blob) const
    {
        loader->loadWithCachedUnitThread(blob, unit);
    }
    void load(QQmlTypeLoader *loader, QQmlDataBlob *blob) const
    {
        loader->m_thread->loadWithCachedUnit(blob, unit);
    }
    void loadAsync(QQmlTypeLoader *loader, QQmlDataBlob *blob) const
    {
        loader->m_thread->loadWithCachedUnitAsync(blob, unit);
    }
};
 
template<typename Loader>
void QQmlTypeLoader::doLoad(const Loader &loader, QQmlDataBlob *blob, Mode mode)
{
#ifdef DATABLOB_DEBUG
    qWarning("QQmlTypeLoader::doLoad(%s): %s thread", qPrintable(blob->urlString()),
             m_thread->isThisThread()?"Compile":"Engine");
#endif
    blob->startLoading();
 
    if (m_thread->isThisThread()) {
        unlock();
        loader.loadThread(this, blob);
        lock();
    } else if (mode == Asynchronous) {
        blob->m_data.setIsAsync(true);
        unlock();
        loader.loadAsync(this, blob);
        lock();
    } else {
        unlock();
        loader.load(this, blob);
        lock();
        if (mode == PreferSynchronous) {
            if (!blob->isCompleteOrError())
                blob->m_data.setIsAsync(true);
        } else {
            Q_ASSERT(mode == Synchronous);
            while (!blob->isCompleteOrError()) {
                m_thread->waitForNextMessage();
            }
        }
    }
}
 
void QQmlTypeLoader::load(QQmlDataBlob *blob, Mode mode)
{
    doLoad(PlainLoader(), blob, mode);
}
 
void QQmlTypeLoader::loadWithStaticData(QQmlDataBlob *blob, const QByteArray &data, Mode mode)
{
    doLoad(StaticLoader(data), blob, mode);
}
 
void QQmlTypeLoader::loadWithCachedUnit(QQmlDataBlob *blob, const QQmlPrivate::CachedQmlUnit *unit, Mode mode)
{
    doLoad(CachedLoader(unit), blob, mode);
}
 
void QQmlTypeLoader::loadWithStaticDataThread(const QQmlDataBlob::Ptr &blob, const QByteArray &data)
{
    ASSERT_LOADTHREAD();
 
    setData(blob, data);
}
 
void QQmlTypeLoader::loadWithCachedUnitThread(const QQmlDataBlob::Ptr &blob, const QQmlPrivate::CachedQmlUnit *unit)
{
    ASSERT_LOADTHREAD();
 
    setCachedUnit(blob, unit);
}
 
void QQmlTypeLoader::loadThread(const QQmlDataBlob::Ptr &blob)
{
    ASSERT_LOADTHREAD();
 
    // Don't continue loading if we've been shutdown
    if (m_thread->isShutdown()) {
        QQmlError error;
        error.setDescription(QLatin1String("Interrupted by shutdown"));
        blob->setError(error);
        return;
    }
 
    if (blob->m_url.isEmpty()) {
        QQmlError error;
        error.setDescription(QLatin1String("Invalid null URL"));
        blob->setError(error);
        return;
    }
 
    if (QQmlFile::isSynchronous(blob->m_url)) {
        const QString fileName = QQmlFile::urlToLocalFileOrQrc(blob->m_url);
        if (!QQml_isFileCaseCorrect(fileName)) {
            blob->setError(QLatin1String("File name case mismatch"));
            return;
        }
 
        blob->m_data.setProgress(1.f);
        if (blob->m_data.isAsync())
            m_thread->callDownloadProgressChanged(blob, 1.);
 
        setData(blob, fileName);
 
    } else {
#if QT_CONFIG(qml_network)
        QNetworkReply *reply = m_thread->networkAccessManager()->get(QNetworkRequest(blob->m_url));
        QQmlTypeLoaderNetworkReplyProxy *nrp = m_thread->networkReplyProxy();
        m_networkReplies.insert(reply, blob);
 
        if (reply->isFinished()) {
            nrp->manualFinished(reply);
        } else {
            QObject::connect(reply, SIGNAL(downloadProgress(qint64,qint64)),
                             nrp, SLOT(downloadProgress(qint64,qint64)));
            QObject::connect(reply, SIGNAL(finished()),
                             nrp, SLOT(finished()));
        }
 
#ifdef DATABLOB_DEBUG
        qWarning("QQmlDataBlob: requested %s", qPrintable(blob->urlString()));
#endif // DATABLOB_DEBUG
#endif // qml_network
    }
}
 
#define DATALOADER_MAXIMUM_REDIRECT_RECURSION 16
 
#ifndef TYPELOADER_MINIMUM_TRIM_THRESHOLD
#define TYPELOADER_MINIMUM_TRIM_THRESHOLD 64
#endif
 
#if QT_CONFIG(qml_network)
void QQmlTypeLoader::networkReplyFinished(QNetworkReply *reply)
{
    Q_ASSERT(m_thread->isThisThread());
 
    reply->deleteLater();
 
    QQmlRefPointer<QQmlDataBlob> blob = m_networkReplies.take(reply);
 
    Q_ASSERT(blob);
 
    blob->m_redirectCount++;
 
    if (blob->m_redirectCount < DATALOADER_MAXIMUM_REDIRECT_RECURSION) {
        QVariant redirect = reply->attribute(QNetworkRequest::RedirectionTargetAttribute);
        if (redirect.isValid()) {
            QUrl url = reply->url().resolved(redirect.toUrl());
            blob->m_finalUrl = url;
            blob->m_finalUrlString.clear();
 
            QNetworkReply *reply = m_thread->networkAccessManager()->get(QNetworkRequest(url));
            QObject *nrp = m_thread->networkReplyProxy();
            QObject::connect(reply, SIGNAL(finished()), nrp, SLOT(finished()));
            m_networkReplies.insert(reply, std::move(blob));
#ifdef DATABLOB_DEBUG
            qWarning("QQmlDataBlob: redirected to %s", qPrintable(blob->finalUrlString()));
#endif
            return;
        }
    }
 
    if (reply->error()) {
        blob->networkError(reply->error());
    } else {
        QByteArray data = reply->readAll();
        setData(blob, data);
    }
}
 
void QQmlTypeLoader::networkReplyProgress(QNetworkReply *reply,
                                                  qint64 bytesReceived, qint64 bytesTotal)
{
    Q_ASSERT(m_thread->isThisThread());
 
    const QQmlRefPointer<QQmlDataBlob> blob = m_networkReplies.value(reply);
 
    Q_ASSERT(blob);
 
    if (bytesTotal != 0) {
        qreal progress = (qreal(bytesReceived) / qreal(bytesTotal));
        blob->m_data.setProgress(progress);
        if (blob->m_data.isAsync())
            m_thread->callDownloadProgressChanged(blob, blob->m_data.progress());
    }
}
#endif // qml_network
 
QQmlEngine *QQmlTypeLoader::engine() const
{
    return m_engine;
}
 
template<class Interface>
void doInitializeEngine(Interface *iface, QQmlTypeLoaderThread *thread, QQmlEngine *engine,
                      const char *uri)
{
    Q_ASSERT(thread->isThisThread() || engine->thread() == QThread::currentThread());
 
    if (thread->isThisThread()) {
        thread->initializeEngine(iface, uri);
    } else {
        Q_ASSERT(engine->thread() == QThread::currentThread());
        iface->initializeEngine(engine, uri);
    }
}
 
void QQmlTypeLoader::initializeEngine(QQmlEngineExtensionInterface *iface, const char *uri)
{
    doInitializeEngine(iface, m_thread, engine(), uri);
}
 
void QQmlTypeLoader::initializeEngine(QQmlExtensionInterface *iface, const char *uri)
{
    doInitializeEngine(iface, m_thread, engine(), uri);
}
 
void QQmlTypeLoader::setData(const QQmlDataBlob::Ptr &blob, const QByteArray &data)
{
    QQmlDataBlob::SourceCodeData d;
    d.inlineSourceCode = QString::fromUtf8(data);
    d.hasInlineSourceCode = true;
    setData(blob, d);
}
 
void QQmlTypeLoader::setData(const QQmlDataBlob::Ptr &blob, const QString &fileName)
{
    QQmlDataBlob::SourceCodeData d;
    d.fileInfo = QFileInfo(fileName);
    setData(blob, d);
}
 
void QQmlTypeLoader::setData(const QQmlDataBlob::Ptr &blob, const QQmlDataBlob::SourceCodeData &d)
{
    Q_TRACE_SCOPE(QQmlCompiling, blob->url());
    QQmlCompilingProfiler prof(profiler(), blob.data());
 
    blob->m_inCallback = true;
 
    blob->dataReceived(d);
 
    if (!blob->isError() && !blob->isWaiting())
        blob->allDependenciesDone();
 
    if (blob->status() != QQmlDataBlob::Error)
        blob->m_data.setStatus(QQmlDataBlob::WaitingForDependencies);
 
    blob->m_inCallback = false;
 
    blob->tryDone();
}
 
void QQmlTypeLoader::setCachedUnit(const QQmlDataBlob::Ptr &blob, const QQmlPrivate::CachedQmlUnit *unit)
{
    Q_TRACE_SCOPE(QQmlCompiling, blob->url());
    QQmlCompilingProfiler prof(profiler(), blob.data());
 
    blob->m_inCallback = true;
 
    blob->initializeFromCachedUnit(unit);
 
    if (!blob->isError() && !blob->isWaiting())
        blob->allDependenciesDone();
 
    if (blob->status() != QQmlDataBlob::Error)
        blob->m_data.setStatus(QQmlDataBlob::WaitingForDependencies);
 
    blob->m_inCallback = false;
 
    blob->tryDone();
}
 
void QQmlTypeLoader::shutdownThread()
{
    if (m_thread && !m_thread->isShutdown())
        m_thread->shutdown();
}
 
QQmlTypeLoader::Blob::PendingImport::PendingImport(
        QQmlTypeLoader::Blob *blob, const QV4::CompiledData::Import *import,
        QQmlImports::ImportFlags flags)
    : uri(blob->stringAt(import->uriIndex))
    , qualifier(blob->stringAt(import->qualifierIndex))
    , type(static_cast<QV4::CompiledData::Import::ImportType>(quint32(import->type)))
    , location(import->location)
    , flags(flags)
    , version(import->version)
{
}
 
QQmlTypeLoader::Blob::Blob(const QUrl &url, QQmlDataBlob::Type type, QQmlTypeLoader *loader)
  : QQmlDataBlob(url, type, loader)
  , m_importCache(new QQmlImports(loader), QQmlRefPointer<QQmlImports>::Adopt)
{
}
 
QQmlTypeLoader::Blob::~Blob()
{
}
 
bool QQmlTypeLoader::Blob::fetchQmldir(const QUrl &url, PendingImportPtr import, int priority, QList<QQmlError> *errors)
{
    QQmlRefPointer<QQmlQmldirData> data = typeLoader()->getQmldir(url);
 
    data->setPriority(this, std::move(import), priority);
 
    if (data->status() == Error) {
        // This qmldir must not exist - which is not an error
        return true;
    } else if (data->status() == Complete) {
        // This data is already available
        return qmldirDataAvailable(data, errors);
    }
 
    // Wait for this data to become available
    addDependency(data.data());
    return true;
}
 
void QQmlTypeLoader::Blob::importQmldirScripts(
        const QQmlTypeLoader::Blob::PendingImportPtr &import,
        const QQmlTypeLoaderQmldirContent &qmldir, const QUrl &qmldirUrl)
{
    const auto qmldirScripts = qmldir.scripts();
    for (const QQmlDirParser::Script &script : qmldirScripts) {
        const QUrl scriptUrl = qmldirUrl.resolved(QUrl(script.fileName));
        QQmlRefPointer<QQmlScriptBlob> blob = typeLoader()->getScript(scriptUrl);
        addDependency(blob.data());
        scriptImported(blob, import->location, script.nameSpace, import->qualifier);
    }
}
 
template<typename URL>
void postProcessQmldir(
        QQmlTypeLoader::Blob *self,
        const QQmlTypeLoader::Blob::PendingImportPtr &import, const QString &qmldirFilePath,
        const URL &qmldirUrl)
{
    const QQmlTypeLoaderQmldirContent qmldir = self->typeLoader()->qmldirContent(qmldirFilePath);
    if (!import->qualifier.isEmpty())
        self->importQmldirScripts(import, qmldir, QUrl(qmldirUrl));
 
    if (qmldir.plugins().isEmpty()) {
        // If the qmldir does not register a plugin, we might still have declaratively
        // registered types (if we are dealing with an application instead of a library)
        // We should use module name given in the qmldir rather than the one given by the
        // import since the import may be a directory import.
        auto module = QQmlMetaType::typeModule(qmldir.typeNamespace(), import->version);
        if (!module)
            QQmlMetaType::qmlRegisterModuleTypes(qmldir.typeNamespace());
        // else: If the module already exists, the types must have been already registered
    }
}
 
bool QQmlTypeLoader::Blob::updateQmldir(const QQmlRefPointer<QQmlQmldirData> &data, const QQmlTypeLoader::Blob::PendingImportPtr &import, QList<QQmlError> *errors)
{
    QString qmldirIdentifier = data->urlString();
    QString qmldirUrl = qmldirIdentifier.left(qmldirIdentifier.lastIndexOf(QLatin1Char('/')) + 1);
 
    typeLoader()->setQmldirContent(qmldirIdentifier, data->content());
 
    const QTypeRevision version = m_importCache->updateQmldirContent(
                typeLoader()->importDatabase(), import->uri, import->qualifier, qmldirIdentifier,
                qmldirUrl, errors);
    if (!version.isValid())
        return false;
 
    // Use more specific version for dependencies if possible
    if (version.hasMajorVersion())
        import->version = version;
 
    if (!loadImportDependencies(import, qmldirIdentifier, import->flags, errors))
        return false;
 
    import->priority = 0;
 
    // Release this reference at destruction
    m_qmldirs << data;
 
    postProcessQmldir(this, import, qmldirIdentifier, qmldirUrl);
    return true;
}
 
bool QQmlTypeLoader::Blob::addScriptImport(const QQmlTypeLoader::Blob::PendingImportPtr &import)
{
    const QUrl url(import->uri);
    const auto module = m_typeLoader->engine()->handle()->moduleForUrl(url);
    QQmlRefPointer<QQmlScriptBlob> blob;
    if (module.native) {
        blob.adopt(new QQmlScriptBlob(url, m_typeLoader));
        blob->initializeFromNative(*module.native);
        blob->tryDone();
    } else {
        blob = typeLoader()->getScript(finalUrl().resolved(url));
    }
    addDependency(blob.data());
    scriptImported(blob, import->location, import->qualifier, QString());
    return true;
}
 
bool QQmlTypeLoader::Blob::addFileImport(const QQmlTypeLoader::Blob::PendingImportPtr &import, QList<QQmlError> *errors)
{
    QQmlImportDatabase *importDatabase = typeLoader()->importDatabase();
    QQmlImports::ImportFlags flags;
 
    QUrl importUrl(import->uri);
    QString path = importUrl.path();
    path.append(QLatin1String(path.endsWith(QLatin1Char('/')) ? "qmldir" : "/qmldir"));
    importUrl.setPath(path);
    QUrl qmldirUrl = finalUrl().resolved(importUrl);
    if (!QQmlImports::isLocal(qmldirUrl)) {
        // This is a remote file; the import is currently incomplete
        flags = QQmlImports::ImportIncomplete;
    }
 
    const QTypeRevision version = m_importCache->addFileImport(
                importDatabase, import->uri, import->qualifier, import->version, flags,
                import->precedence, nullptr, errors);
    if (!version.isValid())
        return false;
 
    // Use more specific version for the qmldir if possible
    if (version.hasMajorVersion())
        import->version = version;
 
    if (flags & QQmlImports::ImportIncomplete) {
        if (!fetchQmldir(qmldirUrl, import, 1, errors))
            return false;
    } else {
        const QString qmldirFilePath = QQmlFile::urlToLocalFileOrQrc(qmldirUrl);
        if (!loadImportDependencies(import, qmldirFilePath, import->flags, errors))
            return false;
 
        postProcessQmldir(this, import, qmldirFilePath, qmldirUrl);
    }
 
    return true;
}
 
bool QQmlTypeLoader::Blob::addLibraryImport(const QQmlTypeLoader::Blob::PendingImportPtr &import, QList<QQmlError> *errors)
{
    QQmlImportDatabase *importDatabase = typeLoader()->importDatabase();
 
    const QQmlImportDatabase::LocalQmldirSearchLocation searchMode =
            QQmlMetaType::isStronglyLockedModule(import->uri, import->version)
                ? QQmlImportDatabase::QmldirCacheOnly
                : QQmlImportDatabase::QmldirFileAndCache;
 
    const QQmlImportDatabase::LocalQmldirResult qmldirResult
            = importDatabase->locateLocalQmldir(
                import->uri, import->version, searchMode,
                [&](const QString &qmldirFilePath, const QString &qmldirUrl) {
        // This is a local library import
        const QTypeRevision actualVersion = m_importCache->addLibraryImport(
                    importDatabase, import->uri, import->qualifier,
                    import->version, qmldirFilePath, qmldirUrl, import->flags, import->precedence,
                    errors);
        if (!actualVersion.isValid())
            return false;
 
        // Use more specific version for dependencies if possible
        if (actualVersion.hasMajorVersion())
            import->version = actualVersion;
 
        if (!loadImportDependencies(import, qmldirFilePath, import->flags, errors)) {
            QQmlError error;
            QString reason = errors->front().description();
            if (reason.size() > 512)
                reason = reason.first(252) + QLatin1String("... ...") + reason.last(252);
            if (import->version.hasMajorVersion()) {
                error.setDescription(QQmlImportDatabase::tr(
                                         "module \"%1\" version %2.%3 cannot be imported because:\n%4")
                                     .arg(import->uri).arg(import->version.majorVersion())
                                     .arg(import->version.hasMinorVersion()
                                          ? QString::number(import->version.minorVersion())
                                          : QLatin1String("x"))
                                     .arg(reason));
            } else {
                error.setDescription(QQmlImportDatabase::tr("module \"%1\" cannot be imported because:\n%2")
                                     .arg(import->uri, reason));
            }
            errors->prepend(error);
            return false;
        }
 
        postProcessQmldir(this, import, qmldirFilePath, qmldirUrl);
        return true;
    });
 
    switch (qmldirResult) {
    case QQmlImportDatabase::QmldirFound:
        return true;
    case QQmlImportDatabase::QmldirNotFound:
    case QQmlImportDatabase::QmldirInterceptedToRemote:
        break;
    case QQmlImportDatabase::QmldirRejected:
        return false;
    }
 
    // If there is a qmldir we cannot see, yet, then we have to wait.
    // The qmldir might contain import directives.
    if (qmldirResult != QQmlImportDatabase::QmldirInterceptedToRemote && (
            // Major version of module already registered:
            // We believe that the registration is complete.
            QQmlMetaType::typeModule(import->uri, import->version)
 
            // Otherwise, try to register further module types.
            || QQmlMetaType::qmlRegisterModuleTypes(import->uri)
 
            // Otherwise, there is no way to register any further types.
            // Try with any module of that name.
            || QQmlMetaType::latestModuleVersion(import->uri).isValid())) {
 
        if (!m_importCache->addLibraryImport(
                    importDatabase, import->uri, import->qualifier, import->version,
                    QString(), QString(), import->flags, import->precedence, errors).isValid()) {
            return false;
        }
    } else {
        // We haven't yet resolved this import
        m_unresolvedImports << import;
 
        const QQmlEngine *engine = typeLoader()->engine();
        const bool hasInterceptors
                = !(QQmlEnginePrivate::get(engine)->urlInterceptors.isEmpty());
 
        // Query any network import paths for this library.
        // Interceptor might redirect local paths.
        QStringList remotePathList = importDatabase->importPathList(
                    hasInterceptors ? QQmlImportDatabase::LocalOrRemote
                                    : QQmlImportDatabase::Remote);
        if (!remotePathList.isEmpty()) {
            // Add this library and request the possible locations for it
            const QTypeRevision version = m_importCache->addLibraryImport(
                        importDatabase, import->uri, import->qualifier, import->version,
                        QString(), QString(), import->flags | QQmlImports::ImportIncomplete,
                        import->precedence, errors);
 
            if (!version.isValid())
                return false;
 
            // Use more specific version for finding the qmldir if possible
            if (version.hasMajorVersion())
                import->version = version;
 
            // Probe for all possible locations
            int priority = 0;
            const QStringList qmlDirPaths = QQmlImports::completeQmldirPaths(
                        import->uri, remotePathList, import->version);
            for (const QString &qmldirPath : qmlDirPaths) {
                if (hasInterceptors) {
                    QUrl url = engine->interceptUrl(
                                QQmlImports::urlFromLocalFileOrQrcOrUrl(qmldirPath),
                                QQmlAbstractUrlInterceptor::QmldirFile);
                    if (!QQmlFile::isLocalFile(url)
                            && !fetchQmldir(url, import, ++priority, errors)) {
                        return false;
                    }
                } else if (!fetchQmldir(QUrl(qmldirPath), import, ++priority, errors)) {
                    return false;
                }
 
            }
        }
    }
 
    return true;
}
 
bool QQmlTypeLoader::Blob::addImport(const QV4::CompiledData::Import *import,
                                     QQmlImports::ImportFlags flags, QList<QQmlError> *errors)
{
    return addImport(std::make_shared<PendingImport>(this, import, flags), errors);
}
 
bool QQmlTypeLoader::Blob::addImport(
        QQmlTypeLoader::Blob::PendingImportPtr import, QList<QQmlError> *errors)
{
    Q_ASSERT(errors);
 
    switch (import->type)
    {
    case QV4::CompiledData::Import::ImportLibrary:
        return addLibraryImport(import, errors);
    case QV4::CompiledData::Import::ImportFile:
        return addFileImport(import ,errors);
    case QV4::CompiledData::Import::ImportScript:
        return addScriptImport(import);
    case QV4::CompiledData::Import::ImportInlineComponent:
        Q_UNREACHABLE_RETURN(false); // addImport is never called with an inline component import
    }
 
    Q_UNREACHABLE_RETURN(false);
}
 
void QQmlTypeLoader::Blob::dependencyComplete(QQmlDataBlob *blob)
{
    if (blob->type() == QQmlDataBlob::QmldirFile) {
        QQmlQmldirData *data = static_cast<QQmlQmldirData *>(blob);
        QList<QQmlError> errors;
        if (!qmldirDataAvailable(data, &errors)) {
            Q_ASSERT(errors.size());
            QQmlError error(errors.takeFirst());
            error.setUrl(m_importCache->baseUrl());
            const QV4::CompiledData::Location importLocation = data->importLocation(this);
            error.setLine(qmlConvertSourceCoordinate<quint32, int>(importLocation.line()));
            error.setColumn(qmlConvertSourceCoordinate<quint32, int>(importLocation.column()));
            errors.prepend(error); // put it back on the list after filling out information.
            setError(errors);
        }
    }
}
 
bool QQmlTypeLoader::Blob::loadDependentImports(
        const QList<QQmlDirParser::Import> &imports, const QString &qualifier,
        QTypeRevision version, quint16 precedence, QQmlImports::ImportFlags flags,
        QList<QQmlError> *errors)
{
    for (const auto &import : imports) {
        if (import.flags & QQmlDirParser::Import::Optional)
            continue;
        auto dependencyImport = std::make_shared<PendingImport>();
        dependencyImport->uri = import.module;
        dependencyImport->qualifier = qualifier;
        dependencyImport->version = (import.flags & QQmlDirParser::Import::Auto)
                ? version : import.version;
        dependencyImport->flags = flags;
        dependencyImport->precedence = precedence;
 
        qCDebug(lcQmlImport)
                << "loading dependent import" << dependencyImport->uri << "version"
                << dependencyImport->version << "as" << dependencyImport->qualifier;
 
        if (!addImport(dependencyImport, errors)) {
            QQmlError error;
            error.setDescription(
                        QString::fromLatin1(
                            "Failed to load dependent import \"%1\" version %2.%3")
                        .arg(dependencyImport->uri)
                        .arg(dependencyImport->version.majorVersion())
                        .arg(dependencyImport->version.minorVersion()));
            errors->append(error);
            return false;
        }
    }
 
    return true;
}
 
bool QQmlTypeLoader::Blob::loadImportDependencies(
        const QQmlTypeLoader::Blob::PendingImportPtr &currentImport, const QString &qmldirUri,
        QQmlImports::ImportFlags flags, QList<QQmlError> *errors)
{
    const QQmlTypeLoaderQmldirContent qmldir = typeLoader()->qmldirContent(qmldirUri);
    const QList<QQmlDirParser::Import> implicitImports
            = QQmlMetaType::moduleImports(currentImport->uri, currentImport->version)
            + qmldir.imports();
 
    // Prevent overflow from one category of import into the other.
    switch (currentImport->precedence) {
    case QQmlImportInstance::Implicit - 1:
    case QQmlImportInstance::Lowest: {
        QQmlError error;
        error.setDescription(
                    QString::fromLatin1("Too many dependent imports for %1 %2.%3")
                    .arg(currentImport->uri)
                    .arg(currentImport->version.majorVersion())
                    .arg(currentImport->version.minorVersion()));
        errors->append(error);
        return false;
    }
    default:
        break;
    }
 
    if (!loadDependentImports(
                implicitImports, currentImport->qualifier, currentImport->version,
                currentImport->precedence + 1, flags, errors)) {
        QQmlError error;
        error.setDescription(
                    QString::fromLatin1(
                        "Failed to load dependencies for module \"%1\" version %2.%3")
                    .arg(currentImport->uri)
                    .arg(currentImport->version.majorVersion())
                    .arg(currentImport->version.minorVersion()));
        errors->append(error);
        return false;
    }
 
    return true;
}
 
bool QQmlTypeLoader::Blob::isDebugging() const
{
    return typeLoader()->engine()->handle()->debugger() != nullptr;
}
 
bool QQmlTypeLoader::Blob::readCacheFile() const
{
    return typeLoader()->engine()->handle()->diskCacheOptions()
            & QV4::ExecutionEngine::DiskCache::QmlcRead;
}
 
bool QQmlTypeLoader::Blob::writeCacheFile() const
{
    return typeLoader()->engine()->handle()->diskCacheOptions()
            & QV4::ExecutionEngine::DiskCache::QmlcWrite;
}
 
QQmlMetaType::CacheMode QQmlTypeLoader::Blob::aotCacheMode() const
{
    const QV4::ExecutionEngine::DiskCacheOptions options
            = typeLoader()->engine()->handle()->diskCacheOptions();
    if (!(options & QV4::ExecutionEngine::DiskCache::Aot))
        return QQmlMetaType::RejectAll;
    if (options & QV4::ExecutionEngine::DiskCache::AotByteCode)
        return QQmlMetaType::AcceptUntyped;
    return QQmlMetaType::RequireFullyTyped;
}
 
bool QQmlTypeLoader::Blob::qmldirDataAvailable(const QQmlRefPointer<QQmlQmldirData> &data, QList<QQmlError> *errors)
{
    return data->processImports(this, [&](PendingImportPtr import) {
        return updateQmldir(data, import, errors);
    });
}
 
QQmlTypeLoader::QQmlTypeLoader(QQmlEngine *engine)
    : m_engine(engine)
    , m_thread(new QQmlTypeLoaderThread(this))
    , m_mutex(m_thread->mutex())
    , m_typeCacheTrimThreshold(TYPELOADER_MINIMUM_TRIM_THRESHOLD)
{
}
 
QQmlTypeLoader::~QQmlTypeLoader()
{
    // Stop the loader thread before releasing resources
    shutdownThread();
 
    clearCache();
 
    invalidate();
}
 
QQmlImportDatabase *QQmlTypeLoader::importDatabase() const
{
    return &QQmlEnginePrivate::get(engine())->importDatabase;
}
 
QUrl QQmlTypeLoader::normalize(const QUrl &unNormalizedUrl)
{
    QUrl normalized(unNormalizedUrl);
    if (normalized.scheme() == QLatin1String("qrc"))
        normalized.setHost(QString()); // map qrc:///a.qml to qrc:/a.qml
    return normalized;
}
 
QQmlRefPointer<QQmlTypeData> QQmlTypeLoader::getType(const QUrl &unNormalizedUrl, Mode mode)
{
    Q_ASSERT(!unNormalizedUrl.isRelative() &&
            (QQmlFile::urlToLocalFileOrQrc(unNormalizedUrl).isEmpty() ||
             !QDir::isRelativePath(QQmlFile::urlToLocalFileOrQrc(unNormalizedUrl))));
 
    const QUrl url = normalize(unNormalizedUrl);
 
    LockHolder<QQmlTypeLoader> holder(this);
 
    QQmlTypeData *typeData = m_typeCache.value(url);
 
    if (!typeData) {
        // Trim before adding the new type, so that we don't immediately trim it away
        if (m_typeCache.size() >= m_typeCacheTrimThreshold)
            trimCache();
 
        typeData = new QQmlTypeData(url, this);
        // TODO: if (compiledData == 0), is it safe to omit this insertion?
        m_typeCache.insert(url, typeData);
        QQmlMetaType::CachedUnitLookupError error = QQmlMetaType::CachedUnitLookupError::NoError;
 
        const QQmlMetaType::CacheMode cacheMode = typeData->aotCacheMode();
        if (const QQmlPrivate::CachedQmlUnit *cachedUnit = (cacheMode != QQmlMetaType::RejectAll)
                ? QQmlMetaType::findCachedCompilationUnit(typeData->url(), cacheMode, &error)
                : nullptr) {
            QQmlTypeLoader::loadWithCachedUnit(typeData, cachedUnit, mode);
        } else {
            typeData->setCachedUnitStatus(error);
            QQmlTypeLoader::load(typeData, mode);
        }
    } else if ((mode == PreferSynchronous || mode == Synchronous) && QQmlFile::isSynchronous(url)) {
        // this was started Asynchronous, but we need to force Synchronous
        // completion now (if at all possible with this type of URL).
 
        if (!m_thread->isThisThread()) {
            // this only works when called directly from the UI thread, but not
            // when recursively called on the QML thread via resolveTypes()
 
            while (!typeData->isCompleteOrError()) {
                m_thread->waitForNextMessage();
            }
        }
    }
 
    return typeData;
}
 
QQmlRefPointer<QQmlTypeData> QQmlTypeLoader::getType(const QByteArray &data, const QUrl &url, Mode mode)
{
    LockHolder<QQmlTypeLoader> holder(this);
 
    QQmlTypeData *typeData = new QQmlTypeData(url, this);
    QQmlTypeLoader::loadWithStaticData(typeData, data, mode);
 
    return QQmlRefPointer<QQmlTypeData>(typeData, QQmlRefPointer<QQmlTypeData>::Adopt);
}
 
QQmlRefPointer<QQmlScriptBlob> QQmlTypeLoader::getScript(const QUrl &unNormalizedUrl)
{
    Q_ASSERT(!unNormalizedUrl.isRelative() &&
            (QQmlFile::urlToLocalFileOrQrc(unNormalizedUrl).isEmpty() ||
             !QDir::isRelativePath(QQmlFile::urlToLocalFileOrQrc(unNormalizedUrl))));
 
    const QUrl url = normalize(unNormalizedUrl);
 
    LockHolder<QQmlTypeLoader> holder(this);
 
    QQmlScriptBlob *scriptBlob = m_scriptCache.value(url);
 
    if (!scriptBlob) {
        scriptBlob = new QQmlScriptBlob(url, this);
        m_scriptCache.insert(url, scriptBlob);
 
        QQmlMetaType::CachedUnitLookupError error = QQmlMetaType::CachedUnitLookupError::NoError;
        const QQmlMetaType::CacheMode cacheMode = scriptBlob->aotCacheMode();
        if (const QQmlPrivate::CachedQmlUnit *cachedUnit = (cacheMode != QQmlMetaType::RejectAll)
                ? QQmlMetaType::findCachedCompilationUnit(scriptBlob->url(), cacheMode, &error)
                : nullptr) {
            QQmlTypeLoader::loadWithCachedUnit(scriptBlob, cachedUnit);
        } else {
            scriptBlob->setCachedUnitStatus(error);
            QQmlTypeLoader::load(scriptBlob);
        }
    }
 
    return scriptBlob;
}
 
QQmlRefPointer<QQmlQmldirData> QQmlTypeLoader::getQmldir(const QUrl &url)
{
    Q_ASSERT(!url.isRelative() &&
            (QQmlFile::urlToLocalFileOrQrc(url).isEmpty() ||
             !QDir::isRelativePath(QQmlFile::urlToLocalFileOrQrc(url))));
    LockHolder<QQmlTypeLoader> holder(this);
 
    QQmlQmldirData *qmldirData = m_qmldirCache.value(url);
 
    if (!qmldirData) {
        qmldirData = new QQmlQmldirData(url, this);
        m_qmldirCache.insert(url, qmldirData);
        QQmlTypeLoader::load(qmldirData);
    }
 
    return qmldirData;
}
 
QString QQmlTypeLoader::absoluteFilePath(const QString &path)
{
    if (path.isEmpty())
        return QString();
    if (path.at(0) == QLatin1Char(':')) {
        // qrc resource
        QFileInfo fileInfo(path);
        return fileInfo.isFile() ? fileInfo.absoluteFilePath() : QString();
    } else if (path.size() > 3 && path.at(3) == QLatin1Char(':') &&
               path.startsWith(QLatin1String("qrc"), Qt::CaseInsensitive)) {
        // qrc resource url
        QFileInfo fileInfo(QQmlFile::urlToLocalFileOrQrc(path));
        return fileInfo.isFile() ? fileInfo.absoluteFilePath() : QString();
    }
#if defined(Q_OS_ANDROID)
    else if (path.size() > 7 && path.at(6) == QLatin1Char(':') && path.at(7) == QLatin1Char('/') &&
           path.startsWith(QLatin1String("assets"), Qt::CaseInsensitive)) {
        // assets resource url
        QFileInfo fileInfo(QQmlFile::urlToLocalFileOrQrc(path));
        return fileInfo.isFile() ? fileInfo.absoluteFilePath() : QString();
    } else if (path.size() > 8 && path.at(7) == QLatin1Char(':') && path.at(8) == QLatin1Char('/') &&
           path.startsWith(QLatin1String("content"), Qt::CaseInsensitive)) {
        // content url
        QFileInfo fileInfo(QQmlFile::urlToLocalFileOrQrc(path));
        return fileInfo.isFile() ? fileInfo.absoluteFilePath() : QString();
    }
#endif
 
    int lastSlash = path.lastIndexOf(QLatin1Char('/'));
    QString dirPath(path.left(lastSlash));
 
    LockHolder<QQmlTypeLoader> holder(this);
    if (!m_importDirCache.contains(dirPath)) {
        bool exists = QDir(dirPath).exists();
        QCache<QString, bool> *entry = exists ? new QCache<QString, bool> : nullptr;
        m_importDirCache.insert(dirPath, entry);
    }
    QCache<QString, bool> *fileSet = m_importDirCache.object(dirPath);
    if (!fileSet)
        return QString();
 
    QString absoluteFilePath;
    QString fileName(path.mid(lastSlash+1, path.size()-lastSlash-1));
 
    bool *value = fileSet->object(fileName);
    if (value) {
        if (*value)
            absoluteFilePath = path;
    } else {
        bool exists = QFile::exists(path);
        fileSet->insert(fileName, new bool(exists));
        if (exists)
            absoluteFilePath = path;
    }
 
    if (absoluteFilePath.size() > 2 && absoluteFilePath.at(0) != QLatin1Char('/') && absoluteFilePath.at(1) != QLatin1Char(':'))
        absoluteFilePath = QFileInfo(absoluteFilePath).absoluteFilePath();
 
    return absoluteFilePath;
}
 
bool QQmlTypeLoader::fileExists(const QString &path, const QString &file)
{
    const QChar nullChar(QChar::Null);
    if (path.isEmpty() || path.contains(nullChar) || file.isEmpty() || file.contains(nullChar))
        return false;
 
    Q_ASSERT(path.endsWith(QLatin1Char('/')));
 
    LockHolder<QQmlTypeLoader> holder(this);
    QCache<QString, bool> *fileSet = m_importDirCache.object(path);
    if (fileSet) {
        if (bool *value = fileSet->object(file))
            return *value;
    } else if (m_importDirCache.contains(path)) {
        // explicit nullptr in cache
        return false;
    }
 
    auto addToCache = [&](const QFileInfo &fileInfo) {
        if (!fileSet) {
            fileSet = fileInfo.dir().exists() ? new QCache<QString, bool> : nullptr;
            m_importDirCache.insert(path, fileSet);
            if (!fileSet)
                return false;
        }
 
        const bool exists = fileInfo.exists();
        fileSet->insert(file, new bool(exists));
        return exists;
    };
 
    if (path.at(0) == QLatin1Char(':')) {
        // qrc resource
        return addToCache(QFileInfo(path + file));
    }
 
    if (path.size() > 3 && path.at(3) == QLatin1Char(':')
            && path.startsWith(QLatin1String("qrc"), Qt::CaseInsensitive)) {
        // qrc resource url
        return addToCache(QFileInfo(QQmlFile::urlToLocalFileOrQrc(path + file)));
    }
 
#if defined(Q_OS_ANDROID)
    if (path.size() > 7 && path.at(6) == QLatin1Char(':') && path.at(7) == QLatin1Char('/')
            && path.startsWith(QLatin1String("assets"), Qt::CaseInsensitive)) {
        // assets resource url
        return addToCache(QFileInfo(QQmlFile::urlToLocalFileOrQrc(path + file)));
    }
 
    if (path.size() > 8 && path.at(7) == QLatin1Char(':') && path.at(8) == QLatin1Char('/')
            && path.startsWith(QLatin1String("content"), Qt::CaseInsensitive)) {
        // content url
        return addToCache(QFileInfo(QQmlFile::urlToLocalFileOrQrc(path + file)));
    }
#endif
 
    return addToCache(QFileInfo(path + file));
}
 
 
bool QQmlTypeLoader::directoryExists(const QString &path)
{
    if (path.isEmpty())
        return false;
 
    bool isResource = path.at(0) == QLatin1Char(':');
#if defined(Q_OS_ANDROID)
    isResource = isResource || path.startsWith(QLatin1String("assets:/")) || path.startsWith(QLatin1String("content:/"));
#endif
 
    if (isResource) {
        // qrc resource
        QFileInfo fileInfo(path);
        return fileInfo.exists() && fileInfo.isDir();
    }
 
    int length = path.size();
    if (path.endsWith(QLatin1Char('/')))
        --length;
    QString dirPath(path.left(length));
 
    LockHolder<QQmlTypeLoader> holder(this);
    if (!m_importDirCache.contains(dirPath)) {
        bool exists = QDir(dirPath).exists();
        QCache<QString, bool> *files = exists ? new QCache<QString, bool> : nullptr;
        m_importDirCache.insert(dirPath, files);
    }
 
    QCache<QString, bool> *fileSet = m_importDirCache.object(dirPath);
    return fileSet != nullptr;
}
 
 
const QQmlTypeLoaderQmldirContent QQmlTypeLoader::qmldirContent(const QString &filePathIn)
{
    LockHolder<QQmlTypeLoader> holder(this);
 
    QString filePath;
 
    // Try to guess if filePathIn is already a URL. This is necessarily fragile, because
    // - paths can contain ':', which might make them appear as URLs with schemes.
    // - windows drive letters appear as schemes (thus "< 2" below).
    // - a "file:" URL is equivalent to the respective file, but will be treated differently.
    // Yet, this heuristic is the best we can do until we pass more structured information here,
    // for example a QUrl also for local files.
    QUrl url(filePathIn);
    if (url.scheme().size() < 2) {
        filePath = filePathIn;
    } else {
        filePath = QQmlFile::urlToLocalFileOrQrc(url);
        if (filePath.isEmpty()) { // Can't load the remote here, but should be cached
            if (auto entry = m_importQmlDirCache.value(filePathIn))
                return **entry;
            else
                return QQmlTypeLoaderQmldirContent();
        }
    }
 
    QQmlTypeLoaderQmldirContent **val = m_importQmlDirCache.value(filePath);
    if (val)
        return **val;
    QQmlTypeLoaderQmldirContent *qmldir = new QQmlTypeLoaderQmldirContent;
 
#define ERROR(description) { QQmlError e; e.setDescription(description); qmldir->setError(e); }
#define NOT_READABLE_ERROR QString(QLatin1String("module \"$$URI$$\" definition \"%1\" not readable"))
#define CASE_MISMATCH_ERROR QString(QLatin1String("cannot load module \"$$URI$$\": File name case mismatch for \"%1\""))
 
    QFile file(filePath);
    if (!QQml_isFileCaseCorrect(filePath)) {
        ERROR(CASE_MISMATCH_ERROR.arg(filePath));
    } else if (file.open(QFile::ReadOnly)) {
        QByteArray data = file.readAll();
        qmldir->setContent(filePath, QString::fromUtf8(data));
    } else {
        ERROR(NOT_READABLE_ERROR.arg(filePath));
    }
 
#undef ERROR
#undef NOT_READABLE_ERROR
#undef CASE_MISMATCH_ERROR
 
    m_importQmlDirCache.insert(filePath, qmldir);
    return *qmldir;
}
 
void QQmlTypeLoader::setQmldirContent(const QString &url, const QString &content)
{
    QQmlTypeLoaderQmldirContent *qmldir;
    QQmlTypeLoaderQmldirContent **val = m_importQmlDirCache.value(url);
    if (val) {
        qmldir = *val;
    } else {
        qmldir = new QQmlTypeLoaderQmldirContent;
        m_importQmlDirCache.insert(url, qmldir);
    }
 
    if (!qmldir->hasContent())
        qmldir->setContent(url, content);
}
 
void QQmlTypeLoader::clearCache()
{
    for (TypeCache::Iterator iter = m_typeCache.begin(), end = m_typeCache.end(); iter != end; ++iter)
        (*iter)->release();
    for (ScriptCache::Iterator iter = m_scriptCache.begin(), end = m_scriptCache.end(); iter != end; ++iter)
        (*iter)->release();
    for (QmldirCache::Iterator iter = m_qmldirCache.begin(), end = m_qmldirCache.end(); iter != end; ++iter)
        (*iter)->release();
 
    qDeleteAll(m_importQmlDirCache);
 
    m_typeCache.clear();
    m_typeCacheTrimThreshold = TYPELOADER_MINIMUM_TRIM_THRESHOLD;
    m_scriptCache.clear();
    m_qmldirCache.clear();
    m_importDirCache.clear();
    m_importQmlDirCache.clear();
    m_checksumCache.clear();
    QQmlMetaType::freeUnusedTypesAndCaches();
}
 
void QQmlTypeLoader::updateTypeCacheTrimThreshold()
{
    int size = m_typeCache.size();
    if (size > m_typeCacheTrimThreshold)
        m_typeCacheTrimThreshold = size * 2;
    if (size < m_typeCacheTrimThreshold / 2)
        m_typeCacheTrimThreshold = qMax(size * 2, TYPELOADER_MINIMUM_TRIM_THRESHOLD);
}
 
void QQmlTypeLoader::trimCache()
{
    while (true) {
        bool deletedOneType = false;
        for (TypeCache::Iterator iter = m_typeCache.begin(), end = m_typeCache.end(); iter != end;)  {
            QQmlTypeData *typeData = iter.value();
 
            // typeData->m_compiledData may be set early on in the proccess of loading a file, so
            // it's important to check the general loading status of the typeData before making any
            // other decisions.
            if (typeData->count() != 1 || (!typeData->isError() && !typeData->isComplete())) {
                ++iter;
                continue;
            }
 
            const QQmlRefPointer<QV4::ExecutableCompilationUnit> &compilationUnit
                = typeData->m_compiledData;
            if (compilationUnit) {
                if (compilationUnit->count()
                        > QQmlMetaType::countInternalCompositeTypeSelfReferences(
                              compilationUnit) + 1) {
                    ++iter;
                    continue;
                }
 
                QQmlMetaType::unregisterInternalCompositeType(compilationUnit);
                Q_ASSERT(compilationUnit->count() == 1);
            }
 
            // There are no live objects of this type
            iter.value()->release();
            iter = m_typeCache.erase(iter);
            deletedOneType = true;
        }
 
        if (!deletedOneType)
            break;
    }
 
    updateTypeCacheTrimThreshold();
 
    QQmlMetaType::freeUnusedTypesAndCaches();
 
    // TODO: release any scripts which are no longer referenced by any types
}
 
bool QQmlTypeLoader::isTypeLoaded(const QUrl &url) const
{
    LockHolder<QQmlTypeLoader> holder(const_cast<QQmlTypeLoader *>(this));
    return m_typeCache.contains(url);
}
 
bool QQmlTypeLoader::isScriptLoaded(const QUrl &url) const
{
    LockHolder<QQmlTypeLoader> holder(const_cast<QQmlTypeLoader *>(this));
    return m_scriptCache.contains(url);
}
 
QT_END_NAMESPACE