From 3356db6f1fe75f39a5f6038e94e5af4b5e99f138 Mon Sep 17 00:00:00 2001
From: Christian Mollekopf <chrigi_1@fastmail.fm>
Date: Mon, 23 Jan 2017 11:17:35 +0100
Subject: Ensure we don't accidentally spawn more transactions than necessary.

---
 common/storage/entitystore.cpp | 7 +++++++
 common/storage/entitystore.h   | 1 +
 common/synchronizer.cpp        | 9 +++++----
 3 files changed, 13 insertions(+), 4 deletions(-)

(limited to 'common')

diff --git a/common/storage/entitystore.cpp b/common/storage/entitystore.cpp
index 6c341e2..51e5da7 100644
--- a/common/storage/entitystore.cpp
+++ b/common/storage/entitystore.cpp
@@ -111,6 +111,7 @@ EntityStore::EntityStore(const ResourceContext &context, const Log::Context &ctx
 void EntityStore::startTransaction(Sink::Storage::DataStore::AccessMode accessMode)
 {
     SinkTraceCtx(d->logCtx) << "Starting transaction: " << accessMode;
+    Q_ASSERT(!d->transaction);
     Sink::Storage::DataStore store(Sink::storageLocation(), d->resourceContext.instanceId(), accessMode);
     d->transaction = store.createTransaction(accessMode);
     Q_ASSERT(d->transaction.validateNamedDatabases());
@@ -119,6 +120,7 @@ void EntityStore::startTransaction(Sink::Storage::DataStore::AccessMode accessMo
 void EntityStore::commitTransaction()
 {
     SinkTraceCtx(d->logCtx) << "Committing transaction";
+    Q_ASSERT(d->transaction);
     d->transaction.commit();
     d->transaction = Storage::DataStore::Transaction();
 }
@@ -130,6 +132,11 @@ void EntityStore::abortTransaction()
     d->transaction = Storage::DataStore::Transaction();
 }
 
+bool EntityStore::hasTransaction() const
+{
+    return d->transaction;
+}
+
 void EntityStore::copyBlobs(ApplicationDomain::ApplicationDomainType &entity, qint64 newRevision)
 {
     const auto directory = d->entityBlobStoragePath(entity.identifier());
diff --git a/common/storage/entitystore.h b/common/storage/entitystore.h
index fe75a02..46410cd 100644
--- a/common/storage/entitystore.h
+++ b/common/storage/entitystore.h
@@ -51,6 +51,7 @@ public:
     void startTransaction(Sink::Storage::DataStore::AccessMode);
     void commitTransaction();
     void abortTransaction();
+    bool hasTransaction() const;
 
     QVector<QByteArray> fullScan(const QByteArray &type);
     QVector<QByteArray> indexLookup(const QByteArray &type, const QueryBase &query, QSet<QByteArray> &appliedFilters, QByteArray &appliedSorting);
diff --git a/common/synchronizer.cpp b/common/synchronizer.cpp
index f731b31..3cd0cb6 100644
--- a/common/synchronizer.cpp
+++ b/common/synchronizer.cpp
@@ -62,7 +62,7 @@ void Synchronizer::enqueueCommand(int commandId, const QByteArray &data)
 
 Storage::EntityStore &Synchronizer::store()
 {
-    mEntityStore->startTransaction(Sink::Storage::DataStore::ReadOnly);
+    Q_ASSERT(mEntityStore->hasTransaction());
     return *mEntityStore;
 }
 
@@ -385,11 +385,13 @@ KAsync::Job<void> Synchronizer::processSyncQueue()
     const auto request = mSyncRequestQueue.takeFirst();
     return KAsync::syncStart<void>([this] {
         mMessageQueue->startTransaction();
+        mEntityStore->startTransaction(Sink::Storage::DataStore::ReadOnly);
         mSyncInProgress = true;
     })
     .then(processRequest(request))
     .then<void>([this](const KAsync::Error &error) {
         SinkTraceCtx(mLogCtx) << "Sync request processed";
+        mEntityStore->abortTransaction();
         mSyncTransaction.abort();
         mMessageQueue->commit();
         mSyncStore.clear();
@@ -409,7 +411,6 @@ KAsync::Job<void> Synchronizer::processSyncQueue()
 void Synchronizer::commit()
 {
     mMessageQueue->commit();
-    mEntityStore->abortTransaction();
     mSyncTransaction.commit();
     mSyncStore.clear();
     if (mSyncInProgress) {
@@ -472,7 +473,8 @@ KAsync::Job<void> Synchronizer::replay(const QByteArray &type, const QByteArray
     Q_ASSERT(metadataBuffer);
     Q_ASSERT(!mSyncStore);
     Q_ASSERT(!mSyncTransaction);
-    mEntityStore->startTransaction(Storage::DataStore::ReadOnly);
+    //The entitystore transaction is handled by processSyncQueue
+    Q_ASSERT(mEntityStore->hasTransaction());
 
     const auto operation = metadataBuffer ? metadataBuffer->operation() : Sink::Operation_Creation;
     const auto uid = Sink::Storage::DataStore::uidFromKey(key);
@@ -525,7 +527,6 @@ KAsync::Job<void> Synchronizer::replay(const QByteArray &type, const QByteArray
         }
         mSyncStore.clear();
         mSyncTransaction.commit();
-        mEntityStore->abortTransaction();
     });
 }
 
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