1 files changed, 110 insertions, 0 deletions

diff --git a/common/entityreader.h b/common/entityreader.h
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+++ b/common/entityreader.h
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+
+/*
+ * Copyright (C) 2016 Christian Mollekopf <mollekopf@kolabsys.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) version 3, or any
+ * later version accepted by the membership of KDE e.V. (or its
+ * successor approved by the membership of KDE e.V.), which shall
+ * act as a proxy defined in Section 6 of version 3 of the license.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+
+#include "sink_export.h"
+#include <domainadaptor.h>
+
+#include "storage.h"
+#include "resultprovider.h"
+#include "adaptorfactoryregistry.h"
+
+namespace Sink {
+
+namespace EntityReaderUtils {
+    SINK_EXPORT QSharedPointer<Sink::ApplicationDomain::BufferAdaptor> getLatest(const Sink::Storage::NamedDatabase &db, const QByteArray &uid, DomainTypeAdaptorFactoryInterface &adaptorFactory, qint64 &retrievedRevision);
+    SINK_EXPORT QSharedPointer<Sink::ApplicationDomain::BufferAdaptor> get(const Sink::Storage::NamedDatabase &db, const QByteArray &key, DomainTypeAdaptorFactoryInterface &adaptorFactory, qint64 &retrievedRevision);
+    SINK_EXPORT QSharedPointer<Sink::ApplicationDomain::BufferAdaptor> getPrevious(const Sink::Storage::NamedDatabase &db, const QByteArray &uid, qint64 revision, DomainTypeAdaptorFactoryInterface &adaptorFactory, qint64 &retrievedRevision);
+};
+
+/**
+ * A synchronous interface to read entities from the storage.
+ *
+ * All callbacks will be called before the end of the function.
+ * The caller must ensure passed in references remain valid for the lifetime of the object.
+ *
+ * This class is meaent to be instantiated temporarily during reads on the stack.
+ *
+ * Note that all objects returned in callbacks are only valid during the execution of the callback and may start pointing into invalid memory if shallow-copied.
+ */
+template<typename DomainType>
+class SINK_EXPORT EntityReader
+{
+    typedef std::function<bool(const typename DomainType::Ptr &domainObject, Sink::Operation operation)> ResultCallback;
+
+public:
+    EntityReader(const QByteArray &resourceType, const QByteArray &mResourceInstanceIdentifier, Sink::Storage::Transaction &transaction);
+    EntityReader(DomainTypeAdaptorFactoryInterface &domainTypeAdaptorFactory, const QByteArray &resourceInstanceIdentifier, Sink::Storage::Transaction &transaction);
+
+    /**
+     * Reads the latest revision of an entity identified by @param uid
+     */
+    DomainType read(const QByteArray &uid) const;
+
+    /**
+     * Reads the revision of the entity identified by @param key (uid + revision)
+     */
+    DomainType readFromKey(const QByteArray &key) const;
+
+    /**
+     * Reads the (revision - 1) of an entity identified by @param uid
+     */
+    DomainType readPrevious(const QByteArray &uid, qint64 revision) const;
+
+    /**
+     * Reads all entities that match @param query.
+     */
+    void query(const Sink::Query &query, const std::function<bool(const DomainType &)> &callback);
+
+    /**
+     * Returns all entities that match @param query.
+     * 
+     * @param offset and @param batchsize can be used to return paginated results.
+     */
+    QPair<qint64, qint64> executeInitialQuery(const Sink::Query &query, int offset, int batchsize, const ResultCallback &callback);
+
+    /**
+     * Returns all changed entities that match @param query starting from @param lastRevision
+     */
+    QPair<qint64, qint64> executeIncrementalQuery(const Sink::Query &query, qint64 lastRevision, const ResultCallback &callback);
+
+private:
+    qint64 replaySet(ResultSet &resultSet, int offset, int batchSize, const ResultCallback &callback);
+
+    void readEntity(const Sink::Storage::NamedDatabase &db, const QByteArray &key,
+        const std::function<void(const Sink::ApplicationDomain::ApplicationDomainType::Ptr &, Sink::Operation)> &resultCallback);
+
+    ResultSet loadInitialResultSet(const Sink::Query &query, QSet<QByteArray> &remainingFilters, QByteArray &remainingSorting);
+    ResultSet loadIncrementalResultSet(qint64 baseRevision, const Sink::Query &query, QSet<QByteArray> &remainingFilters);
+
+    ResultSet filterAndSortSet(ResultSet &resultSet, const std::function<bool(const Sink::ApplicationDomain::ApplicationDomainType::Ptr &domainObject)> &filter,
+        const Sink::Storage::NamedDatabase &db, bool initialQuery, const QByteArray &sortProperty);
+    std::function<bool(const Sink::ApplicationDomain::ApplicationDomainType::Ptr &domainObject)> getFilter(const QSet<QByteArray> remainingFilters, const Sink::Query &query);
+    QPair<qint64, qint64> load(const Sink::Query &query, const std::function<ResultSet(QSet<QByteArray> &, QByteArray &)> &baseSetRetriever, bool initialQuery, int offset, int batchSize, const ResultCallback &callback);
+
+private:
+    QByteArray mResourceInstanceIdentifier;
+    Sink::Storage::Transaction &mTransaction;
+    std::shared_ptr<DomainTypeAdaptorFactoryInterface> mDomainTypeAdaptorFactoryPtr;
+    DomainTypeAdaptorFactoryInterface &mDomainTypeAdaptorFactory;
+};
+
+}