Introduced a QueryRunner object

The QueryRunner object lives for the duration of the query (so just
for the initial query for non-live queries, and for the lifetime of the
result model for live queries).
It's supposed to handle all the threading internally and decouple the
lifetime of the facade.

1 files changed, 5 insertions, 277 deletions

diff --git a/common/facade.cpp b/common/facade.cpp
index 92124fc..1d6b9a7 100644
--- a/common/facade.cpp
+++ b/common/facade.cpp
@@ -24,76 +24,10 @@
 #include "storage.h"
 #include "definitions.h"
 #include "domainadaptor.h"
+#include "queryrunner.h"
 
 using namespace Akonadi2;
 
-/**
- * A QueryRunner runs a query and updates the corresponding result set.
- * 
- * The lifetime of the QueryRunner is defined by the resut set (otherwise it's doing useless work),
- * and by how long a result set must be updated. If the query is one off the runner dies after the execution,
- * otherwise it lives on the react to changes and updates the corresponding result set.
- * 
- * QueryRunner has to keep ResourceAccess alive in order to keep getting updates.
- */
-class QueryRunner : public QObject
-{
-    Q_OBJECT
-public:
-    typedef std::function<KAsync::Job<void>()> QueryFunction;
-
-    QueryRunner(const Akonadi2::Query &query) {};
-    /**
-     * Starts query
-     */
-    KAsync::Job<void> run(qint64 newRevision = 0)
-    {
-        return queryFunction();
-    }
-
-    /**
-     * Set the query to run
-     */
-    void setQuery(const QueryFunction &query)
-    {
-        queryFunction = query;
-    }
-
-public slots:
-    /**
-     * Rerun query with new revision
-     */
-    void revisionChanged(qint64 newRevision)
-    {
-        Trace() << "New revision: " << newRevision;
-        run().exec();
-    }
-
-private:
-    QueryFunction queryFunction;
-};
-
-static inline ResultSet fullScan(const Akonadi2::Storage::Transaction &transaction, const QByteArray &bufferType)
-{
-    //TODO use a result set with an iterator, to read values on demand
-    QVector<QByteArray> keys;
-    transaction.openDatabase(bufferType + ".main").scan(QByteArray(), [&](const QByteArray &key, const QByteArray &value) -> bool {
-        //Skip internals
-        if (Akonadi2::Storage::isInternalKey(key)) {
-            return true;
-        }
-        keys << Akonadi2::Storage::uidFromKey(key);
-        return true;
-    },
-    [](const Akonadi2::Storage::Error &error) {
-        qWarning() << "Error during query: " << error.message;
-    });
-
-    Trace() << "Full scan found " << keys.size() << " results";
-    return ResultSet(keys);
-}
-
-
 
 template<class DomainType>
 GenericFacade<DomainType>::GenericFacade(const QByteArray &resourceIdentifier, const DomainTypeAdaptorFactoryInterface::Ptr &adaptorFactory , const QSharedPointer<Akonadi2::ResourceAccessInterface> resourceAccess)
@@ -150,220 +84,14 @@ KAsync::Job<void> GenericFacade<DomainType>::remove(const DomainType &domainObje
 }
 
 template<class DomainType>
-KAsync::Job<void> GenericFacade<DomainType>::load(const Akonadi2::Query &query, Akonadi2::ResultProviderInterface<typename DomainType::Ptr> &resultProvider)
-{
-    //We delegate loading of initial data to the result provider, os it can decide for itself what it needs to load.
-    resultProvider.setFetcher([this, query, &resultProvider](const typename DomainType::Ptr &parent) {
-        const qint64 newRevision = executeInitialQuery(query, parent, resultProvider);
-        mResourceAccess->sendRevisionReplayedCommand(newRevision);
-    });
-
-
-    //In case of a live query we keep the runner for as long alive as the result provider exists
-    if (query.liveQuery) {
-        auto runner = QSharedPointer<QueryRunner>::create(query);
-        //Incremental updates are always loaded directly, leaving it up to the result to discard the changes if they are not interesting
-        runner->setQuery([this, query, &resultProvider] () -> KAsync::Job<void> {
-            return KAsync::start<void>([this, query, &resultProvider](KAsync::Future<void> &future) {
-                const qint64 newRevision = executeIncrementalQuery(query, resultProvider);
-                mResourceAccess->sendRevisionReplayedCommand(newRevision);
-                future.setFinished();
-            });
-        });
-        resultProvider.setQueryRunner(runner);
-        //Ensure the connection is open, if it wasn't already opened
-        //TODO If we are not connected already, we have to check for the latest revision once connected, otherwise we could miss some updates
-        mResourceAccess->open();
-        QObject::connect(mResourceAccess.data(), &Akonadi2::ResourceAccess::revisionChanged, runner.data(), &QueryRunner::revisionChanged);
-    }
-    return KAsync::null<void>();
-}
-
-    //TODO move into result provider?
-template<class DomainType>
-void GenericFacade<DomainType>::replaySet(ResultSet &resultSet, Akonadi2::ResultProviderInterface<typename DomainType::Ptr> &resultProvider)
-{
-    while (resultSet.next([&resultProvider](const Akonadi2::ApplicationDomain::ApplicationDomainType::Ptr &value, Akonadi2::Operation operation) -> bool {
-        switch (operation) {
-        case Akonadi2::Operation_Creation:
-            // Trace() << "Got creation";
-            resultProvider.add(Akonadi2::ApplicationDomain::ApplicationDomainType::getInMemoryRepresentation<DomainType>(*value).template staticCast<DomainType>());
-            break;
-        case Akonadi2::Operation_Modification:
-            // Trace() << "Got modification";
-            resultProvider.modify(Akonadi2::ApplicationDomain::ApplicationDomainType::getInMemoryRepresentation<DomainType>(*value).template staticCast<DomainType>());
-            break;
-        case Akonadi2::Operation_Removal:
-            // Trace() << "Got removal";
-            resultProvider.remove(Akonadi2::ApplicationDomain::ApplicationDomainType::getInMemoryRepresentation<DomainType>(*value).template staticCast<DomainType>());
-            break;
-        }
-        return true;
-    })){};
-}
-
-template<class DomainType>
-void GenericFacade<DomainType>::readEntity(const Akonadi2::Storage::NamedDatabase &db, const QByteArray &key, const std::function<void(const Akonadi2::ApplicationDomain::ApplicationDomainType::Ptr &, Akonadi2::Operation)> &resultCallback)
-{
-    //This only works for a 1:1 mapping of resource to domain types.
-    //Not i.e. for tags that are stored as flags in each entity of an imap store.
-    //additional properties that don't have a 1:1 mapping (such as separately stored tags),
-    //could be added to the adaptor.
-    //
-    // Akonadi2::Storage::getLatest(transaction, bufferTye, key);
-    db.findLatest(key, [=](const QByteArray &key, const QByteArray &value) -> bool {
-        Akonadi2::EntityBuffer buffer(value.data(), value.size());
-        const Akonadi2::Entity &entity = buffer.entity();
-        const auto metadataBuffer = Akonadi2::EntityBuffer::readBuffer<Akonadi2::Metadata>(entity.metadata());
-        Q_ASSERT(metadataBuffer);
-        const qint64 revision = metadataBuffer ? metadataBuffer->revision() : -1;
-        resultCallback(DomainType::Ptr::create(mResourceInstanceIdentifier, Akonadi2::Storage::uidFromKey(key), revision, mDomainTypeAdaptorFactory->createAdaptor(entity)), metadataBuffer->operation());
-        return false;
-    },
-    [](const Akonadi2::Storage::Error &error) {
-        qWarning() << "Error during query: " << error.message;
-    });
-}
-
-template<class DomainType>
-ResultSet GenericFacade<DomainType>::loadInitialResultSet(const Akonadi2::Query &query, Akonadi2::Storage::Transaction &transaction, QSet<QByteArray> &remainingFilters)
+QPair<KAsync::Job<void>, typename ResultEmitter<typename DomainType::Ptr>::Ptr> GenericFacade<DomainType>::load(const Akonadi2::Query &query)
 {
-    QSet<QByteArray> appliedFilters;
-    auto resultSet = Akonadi2::ApplicationDomain::TypeImplementation<DomainType>::queryIndexes(query, mResourceInstanceIdentifier, appliedFilters, transaction);
-    remainingFilters = query.propertyFilter.keys().toSet() - appliedFilters;
-
-    //We do a full scan if there were no indexes available to create the initial set.
-    if (appliedFilters.isEmpty()) {
-        //TODO this should be replaced by an index lookup as well
-        resultSet = fullScan(transaction, bufferTypeForDomainType());
-    }
-    return resultSet;
-}
-
-template<class DomainType>
-ResultSet GenericFacade<DomainType>::loadIncrementalResultSet(qint64 baseRevision, const Akonadi2::Query &query, Akonadi2::Storage::Transaction &transaction, QSet<QByteArray> &remainingFilters)
-{
-    const auto bufferType = bufferTypeForDomainType();
-    auto revisionCounter = QSharedPointer<qint64>::create(baseRevision);
-    remainingFilters = query.propertyFilter.keys().toSet();
-    return ResultSet([bufferType, revisionCounter, &transaction]() -> QByteArray {
-        const qint64 topRevision = Akonadi2::Storage::maxRevision(transaction);
-        //Spit out the revision keys one by one.
-        while (*revisionCounter <= topRevision) {
-            const auto uid = Akonadi2::Storage::getUidFromRevision(transaction, *revisionCounter);
-            const auto type = Akonadi2::Storage::getTypeFromRevision(transaction, *revisionCounter);
-            Trace() << "Revision" << *revisionCounter << type << uid;
-            if (type != bufferType) {
-                //Skip revision
-                *revisionCounter += 1;
-                continue;
-            }
-            const auto key = Akonadi2::Storage::assembleKey(uid, *revisionCounter);
-            *revisionCounter += 1;
-            return key;
-        }
-        Trace() << "Finished reading incremental result set:" << *revisionCounter;
-        //We're done
-        return QByteArray();
-    });
-}
-
-template<class DomainType>
-ResultSet GenericFacade<DomainType>::filterSet(const ResultSet &resultSet, const std::function<bool(const Akonadi2::ApplicationDomain::ApplicationDomainType::Ptr &domainObject)> &filter, const Akonadi2::Storage::NamedDatabase &db, bool initialQuery)
-{
-    auto resultSetPtr = QSharedPointer<ResultSet>::create(resultSet);
-
-    //Read through the source values and return whatever matches the filter
-    std::function<bool(std::function<void(const Akonadi2::ApplicationDomain::ApplicationDomainType::Ptr &, Akonadi2::Operation)>)> generator = [this, resultSetPtr, &db, filter, initialQuery](std::function<void(const Akonadi2::ApplicationDomain::ApplicationDomainType::Ptr &, Akonadi2::Operation)> callback) -> bool {
-        while (resultSetPtr->next()) {
-            //readEntity is only necessary if we actually want to filter or know the operation type (but not a big deal if we do it always I guess)
-            readEntity(db, resultSetPtr->id(), [this, filter, callback, initialQuery](const Akonadi2::ApplicationDomain::ApplicationDomainType::Ptr &domainObject, Akonadi2::Operation operation) {
-                //Always remove removals, they probably don't match due to non-available properties
-                if (filter(domainObject) || operation == Akonadi2::Operation_Removal) {
-                    if (initialQuery) {
-                        //We're not interested in removals during the initial query
-                        if (operation != Akonadi2::Operation_Removal) {
-                            callback(domainObject, Akonadi2::Operation_Creation);
-                        }
-                    } else {
-                        callback(domainObject, operation);
-                    }
-                }
-            });
-        }
-        return false;
-    };
-    return ResultSet(generator);
-}
-
-
-template<class DomainType>
-std::function<bool(const Akonadi2::ApplicationDomain::ApplicationDomainType::Ptr &domainObject)> GenericFacade<DomainType>::getFilter(const QSet<QByteArray> remainingFilters, const Akonadi2::Query &query)
-{
-    return [remainingFilters, query](const Akonadi2::ApplicationDomain::ApplicationDomainType::Ptr &domainObject) -> bool {
-        for (const auto &filterProperty : remainingFilters) {
-            const auto property = domainObject->getProperty(filterProperty);
-            if (property.isValid()) {
-                //TODO implement other comparison operators than equality
-                if (property != query.propertyFilter.value(filterProperty)) {
-                    Trace() << "Filtering entity due to property mismatch: " << domainObject->getProperty(filterProperty);
-                    return false;
-                }
-            } else {
-                Warning() << "Ignored property filter because value is invalid: " << filterProperty;
-            }
-        }
-        return true;
-    };
-}
-
-template<class DomainType>
-qint64 GenericFacade<DomainType>::load(const Akonadi2::Query &query, const std::function<ResultSet(Akonadi2::Storage::Transaction &, QSet<QByteArray> &)> &baseSetRetriever, Akonadi2::ResultProviderInterface<typename DomainType::Ptr> &resultProvider, bool initialQuery)
-{
-    Akonadi2::Storage storage(Akonadi2::storageLocation(), mResourceInstanceIdentifier);
-    storage.setDefaultErrorHandler([](const Akonadi2::Storage::Error &error) {
-        Warning() << "Error during query: " << error.store << error.message;
-    });
-    auto transaction = storage.createTransaction(Akonadi2::Storage::ReadOnly);
-    auto db = transaction.openDatabase(bufferTypeForDomainType() + ".main");
-
-    QSet<QByteArray> remainingFilters;
-    auto resultSet = baseSetRetriever(transaction, remainingFilters);
-    auto filteredSet = filterSet(resultSet, getFilter(remainingFilters, query), db, initialQuery);
-    replaySet(filteredSet, resultProvider);
-    resultProvider.setRevision(Akonadi2::Storage::maxRevision(transaction));
-    return Akonadi2::Storage::maxRevision(transaction);
+    //The runner lives for the lifetime of the query
+    auto runner = new QueryRunner<DomainType>(query, mResourceAccess, mResourceInstanceIdentifier, mDomainTypeAdaptorFactory, bufferTypeForDomainType());
+    return qMakePair(KAsync::null<void>(), runner->emitter());
 }
 
 
-template<class DomainType>
-qint64 GenericFacade<DomainType>::executeIncrementalQuery(const Akonadi2::Query &query, Akonadi2::ResultProviderInterface<typename DomainType::Ptr> &resultProvider)
-{
-    const qint64 baseRevision = resultProvider.revision() + 1;
-    Trace() << "Running incremental query " << baseRevision;
-    return load(query, [&](Akonadi2::Storage::Transaction &transaction, QSet<QByteArray> &remainingFilters) -> ResultSet {
-        return loadIncrementalResultSet(baseRevision, query, transaction, remainingFilters);
-    }, resultProvider, false);
-}
-
-template<class DomainType>
-qint64 GenericFacade<DomainType>::executeInitialQuery(const Akonadi2::Query &query, const typename DomainType::Ptr &parent, Akonadi2::ResultProviderInterface<typename DomainType::Ptr> &resultProvider)
-{
-    auto modifiedQuery = query;
-    if (!query.parentProperty.isEmpty()) {
-        if (parent) {
-            Trace() << "Running initial query for parent:" << parent->identifier();
-            modifiedQuery.propertyFilter.insert(query.parentProperty, parent->identifier());
-        } else {
-            Trace() << "Running initial query for toplevel";
-            modifiedQuery.propertyFilter.insert(query.parentProperty, QVariant());
-        }
-    }
-    return load(modifiedQuery, [&](Akonadi2::Storage::Transaction &transaction, QSet<QByteArray> &remainingFilters) -> ResultSet {
-        return loadInitialResultSet(modifiedQuery, transaction, remainingFilters);
-    }, resultProvider, true);
-}
-
 template class Akonadi2::GenericFacade<Akonadi2::ApplicationDomain::Folder>;
 template class Akonadi2::GenericFacade<Akonadi2::ApplicationDomain::Mail>;
 template class Akonadi2::GenericFacade<Akonadi2::ApplicationDomain::Event>;