Refactored the generic resource to use separate classes for

changereplay and synchronization.

This cleans up the API and avoids the excessive passing around of
transactions. It also provides more flexibility in eventually using
different synchronization strategies for different resources.

1 files changed, 102 insertions, 0 deletions

diff --git a/common/changereplay.cpp b/common/changereplay.cpp
new file mode 100644
index 0000000..2447b6e
--- /dev/null
+++ b/common/changereplay.cpp
@@ -0,0 +1,102 @@
+/*
+ * 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/>.
+ */
+#include "changereplay.h"
+
+#include "entitybuffer.h"
+#include "log.h"
+#include "definitions.h"
+#include "bufferutils.h"
+
+using namespace Sink;
+
+#undef DEBUG_AREA
+#define DEBUG_AREA "resource.changereplay"
+
+ChangeReplay::ChangeReplay(const QByteArray &resourceName)
+    : mStorage(storageLocation(), resourceName, Storage::ReadOnly), mChangeReplayStore(storageLocation(), resourceName + ".changereplay", Storage::ReadWrite)
+{
+    Trace() << "Created change replay: " << resourceName;
+}
+
+qint64 ChangeReplay::getLastReplayedRevision()
+{
+    qint64 lastReplayedRevision = 0;
+    auto replayStoreTransaction = mChangeReplayStore.createTransaction(Storage::ReadOnly);
+    replayStoreTransaction.openDatabase().scan("lastReplayedRevision",
+        [&lastReplayedRevision](const QByteArray &key, const QByteArray &value) -> bool {
+            lastReplayedRevision = value.toLongLong();
+            return false;
+        },
+        [](const Storage::Error &) {});
+    return lastReplayedRevision;
+}
+
+bool ChangeReplay::allChangesReplayed()
+{
+    const qint64 topRevision = Storage::maxRevision(mStorage.createTransaction(Storage::ReadOnly, [](const Sink::Storage::Error &error) {
+        Warning() << error.message;
+    }));
+    const qint64 lastReplayedRevision = getLastReplayedRevision();
+    Trace() << "All changes replayed " << topRevision << lastReplayedRevision;
+    return (lastReplayedRevision >= topRevision);
+}
+
+void ChangeReplay::revisionChanged()
+{
+    auto mainStoreTransaction = mStorage.createTransaction(Storage::ReadOnly, [](const Sink::Storage::Error &error) {
+        Warning() << error.message;
+    });
+    auto replayStoreTransaction = mChangeReplayStore.createTransaction(Storage::ReadWrite, [](const Sink::Storage::Error &error) {
+        Warning() << error.message;
+    });
+    qint64 lastReplayedRevision = 1;
+    replayStoreTransaction.openDatabase().scan("lastReplayedRevision",
+        [&lastReplayedRevision](const QByteArray &key, const QByteArray &value) -> bool {
+            lastReplayedRevision = value.toLongLong();
+            return false;
+        },
+        [](const Storage::Error &) {});
+    const qint64 topRevision = Storage::maxRevision(mainStoreTransaction);
+
+    Trace() << "Changereplay from " << lastReplayedRevision << " to " << topRevision;
+    if (lastReplayedRevision <= topRevision) {
+        qint64 revision = lastReplayedRevision;
+        for (; revision <= topRevision; revision++) {
+            const auto uid = Storage::getUidFromRevision(mainStoreTransaction, revision);
+            const auto type = Storage::getTypeFromRevision(mainStoreTransaction, revision);
+            const auto key = Storage::assembleKey(uid, revision);
+            Storage::mainDatabase(mainStoreTransaction, type)
+                .scan(key,
+                    [&lastReplayedRevision, type, this](const QByteArray &key, const QByteArray &value) -> bool {
+                        replay(type, key, value).exec();
+                        // TODO make for loop async, and pass to async replay function together with type
+                        Trace() << "Replaying " << key;
+                        return false;
+                    },
+                    [key](const Storage::Error &) { ErrorMsg() << "Failed to replay change " << key; });
+        }
+        revision--;
+        replayStoreTransaction.openDatabase().write("lastReplayedRevision", QByteArray::number(revision));
+        replayStoreTransaction.commit();
+        Trace() << "Replayed until " << revision;
+    }
+    emit changesReplayed();
+}
+