From 2beb09e8b3f4922a15ec0abde737d4cf9b9d4f8b Mon Sep 17 00:00:00 2001
From: Christian Mollekopf <chrigi_1@fastmail.fm>
Date: Thu, 22 Feb 2018 10:16:18 +0100
Subject: Deal with removals in reduced queries

---
 common/datastorequery.cpp      | 22 +++++++++++++++++-----
 common/datastorequery.h        |  7 +++++++
 common/storage/entitystore.cpp |  2 +-
 3 files changed, 25 insertions(+), 6 deletions(-)

(limited to 'common')

diff --git a/common/datastorequery.cpp b/common/datastorequery.cpp
index 218796f..dacc8ab 100644
--- a/common/datastorequery.cpp
+++ b/common/datastorequery.cpp
@@ -300,11 +300,18 @@ public:
     bool next(const std::function<void(const ResultSet::Result &)> &callback) Q_DECL_OVERRIDE {
         bool foundValue = false;
         while(!foundValue && mSource->next([this, callback, &foundValue](const ResultSet::Result &result) {
-                if (result.operation == Sink::Operation_Removal) {
-                    callback(result);
-                    return false;
-                }
-                auto reductionValue = result.entity.getProperty(mReductionProperty);
+                const auto reductionValue = [&] {
+                    if (result.operation == Sink::Operation_Removal) {
+                        //For removals we have to read the last revision to get a value, and thus be able to find the correct thread.
+                        QVariant reductionValue;
+                        readPrevious(result.entity.identifier(), [&] (const ApplicationDomain::ApplicationDomainType &prev) {
+                            reductionValue = prev.getProperty(mReductionProperty);
+                        });
+                        return reductionValue;
+                    } else {
+                        return result.entity.getProperty(mReductionProperty);
+                    }
+                }();
                 const auto &reductionValueBa = getByteArray(reductionValue);
                 if (!mReducedValues.contains(reductionValueBa)) {
                     //Only reduce every value once.
@@ -439,6 +446,11 @@ void DataStoreQuery::readEntity(const QByteArray &key, const BufferCallback &res
     mStore.readLatest(mType, key, resultCallback);
 }
 
+void DataStoreQuery::readPrevious(const QByteArray &key, const std::function<void (const ApplicationDomain::ApplicationDomainType &)> &callback)
+{
+    mStore.readPrevious(mType, key, mStore.maxRevision(), callback);
+}
+
 QVector<QByteArray> DataStoreQuery::indexLookup(const QByteArray &property, const QVariant &value)
 {
     return mStore.indexLookup(mType, property, value);
diff --git a/common/datastorequery.h b/common/datastorequery.h
index 8800644..2311585 100644
--- a/common/datastorequery.h
+++ b/common/datastorequery.h
@@ -62,6 +62,7 @@ private:
     QVector<QByteArray> indexLookup(const QByteArray &property, const QVariant &value);
 
     void readEntity(const QByteArray &key, const BufferCallback &resultCallback);
+    void readPrevious(const QByteArray &key, const std::function<void (const Sink::ApplicationDomain::ApplicationDomainType &)> &callback);
 
     ResultSet createFilteredSet(ResultSet &resultSet, const FilterFunction &);
     QVector<QByteArray> loadIncrementalResultSet(qint64 baseRevision);
@@ -107,6 +108,12 @@ public:
         return mDatastore->indexLookup(property, value);
     }
 
+    void readPrevious(const QByteArray &key, const std::function<void (const Sink::ApplicationDomain::ApplicationDomainType &)> &callback)
+    {
+        Q_ASSERT(mDatastore);
+        mDatastore->readPrevious(key, callback);
+    }
+
     virtual void skip() { mSource->skip(); }
 
     //Returns true for as long as a result is available
diff --git a/common/storage/entitystore.cpp b/common/storage/entitystore.cpp
index 020f3fd..7da7efa 100644
--- a/common/storage/entitystore.cpp
+++ b/common/storage/entitystore.cpp
@@ -563,7 +563,7 @@ void EntityStore::readPrevious(const QByteArray &type, const QByteArray &uid, qi
             return true;
         },
         [&](const Sink::Storage::DataStore::Error &error) { SinkWarningCtx(d->logCtx) << "Failed to read current value from storage: " << error.message; }, true);
-    return readEntity(type, Sink::Storage::DataStore::assembleKey(uid, latestRevision), callback);
+    readEntity(type, Sink::Storage::DataStore::assembleKey(uid, latestRevision), callback);
 }
 
 void EntityStore::readPrevious(const QByteArray &type, const QByteArray &uid, qint64 revision, const std::function<void(const ApplicationDomain::ApplicationDomainType &)> callback)
-- 
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