From be8dba1827ec54ec11d9a3ef143db9ad7f7f38df Mon Sep 17 00:00:00 2001
From: Christian Mollekopf <chrigi_1@fastmail.fm>
Date: Mon, 26 Sep 2016 11:58:38 +0200
Subject: The threading reduction is working.

---
 common/datastorequery.cpp | 121 +++++++++++++++++++++++++++++-----------------
 1 file changed, 76 insertions(+), 45 deletions(-)

(limited to 'common/datastorequery.cpp')

diff --git a/common/datastorequery.cpp b/common/datastorequery.cpp
index 95df1a0..7c0fdea 100644
--- a/common/datastorequery.cpp
+++ b/common/datastorequery.cpp
@@ -141,51 +141,78 @@ public:
     }
 };
 
-/* class Reduction : public FilterBase { */
-/* public: */
-/*     typedef QSharedPointer<Reduction> Ptr; */
+class Reduce : public FilterBase {
+public:
+    typedef QSharedPointer<Reduce> Ptr;
+
+    QHash<QByteArray, QVariant> mAggregateValues;
+    QByteArray mReductionProperty;
+    QByteArray mSelectionProperty;
+    enum SelectionComparator {
+        Max
+        /* Min, */
+        /* First */
+    };
+    SelectionComparator mSelectionComparator;
 
-/*     QHash<QByteArray, QDateTime> aggregateValues; */
+    Reduce(const QByteArray &reductionProperty, const QByteArray &selectionProperty, SelectionComparator comparator, FilterBase::Ptr source, DataStoreQuery *store)
+        : FilterBase(source, store),
+        mReductionProperty(reductionProperty),
+        mSelectionProperty(selectionProperty),
+        mSelectionComparator(comparator)
+    {
 
-/*     Reduction(FilterBase::Ptr source, DataStoreQuery *store) */
-/*         : FilterBase(source, store) */
-/*     { */
+    }
 
-/*     } */
+    virtual ~Reduce(){}
 
-/*     virtual ~Reduction(){} */
-
-/*     bool next(const std::function<void(const QByteArray &uid, const Sink::EntityBuffer &entityBuffer)> &callback) Q_DECL_OVERRIDE { */
-/*         bool foundValue = false; */
-/*         while(!foundValue && mSource->next([this, callback, &foundValue](const QByteArray &uid, const Sink::EntityBuffer &entityBuffer) { */
-/*                 const auto operation = entityBuffer.operation(); */
-/*                 SinkTrace() << "Filter: " << uid << operation; */
-/*                 //Always accept removals. They can't match the filter since the data is gone. */
-/*                 if (operation == Sink::Operation_Removal) { */
-/*                     callback(uid, entityBuffer); */
-/*                     foundValue = true; */
-/*                 } else if (matchesFilter(uid, entityBuffer)) { */
-/*                     callback(uid, entityBuffer); */
-/*                     foundValue = true; */
-/*                 } */
-/*                 return false; */
-/*             })) */
-/*         {} */
-/*         return foundValue; */
-/*     } */
+    static QByteArray getByteArray(const QVariant &value)
+    {
+        if (value.type() == QVariant::DateTime) {
+            return value.toDateTime().toString().toLatin1();
+        }
+        if (value.isValid() && !value.toByteArray().isEmpty()) {
+            return value.toByteArray();
+        }
+        return QByteArray();
+    }
 
-/*     bool matchesFilter(const QByteArray &uid, const Sink::EntityBuffer &entityBuffer) { */
-/*         for (const auto &filterProperty : propertyFilter.keys()) { */
-/*             const auto property = getProperty(entityBuffer.entity(), filterProperty); */
-/*             const auto comparator = propertyFilter.value(filterProperty); */
-/*             if (!comparator.matches(property)) { */
-/*                 SinkTrace() << "Filtering entity due to property mismatch on filter: " << filterProperty << property << ":" << comparator.value; */
-/*                 return false; */
-/*             } */
-/*         } */
-/*         return true; */
-/*     } */
-/* }; */
+    static bool compare(const QVariant &left, const QVariant &right, SelectionComparator comparator)
+    {
+        if (comparator == Max) {
+            return left > right;
+        }
+        return false;
+    }
+
+    bool next(const std::function<void(Sink::Operation operation, const QByteArray &uid, const Sink::EntityBuffer &entityBuffer)> &callback) Q_DECL_OVERRIDE {
+        bool foundValue = false;
+        while(!foundValue && mSource->next([this, callback, &foundValue](Sink::Operation operation, const QByteArray &uid, const Sink::EntityBuffer &entityBuffer) {
+                auto reductionValue = getProperty(entityBuffer.entity(), mReductionProperty);
+                if (!mAggregateValues.contains(getByteArray(reductionValue))) {
+                    QVariant selectionResultValue;
+                    QByteArray selectionResult;
+                    auto results = indexLookup(mReductionProperty, reductionValue);
+                    for (const auto r : results) {
+                        readEntity(r, [&, this](const QByteArray &uid, const Sink::EntityBuffer &entityBuffer) {
+                            auto selectionValue = getProperty(entityBuffer.entity(), mSelectionProperty);
+                            if (!selectionResultValue.isValid() || compare(selectionValue, selectionResultValue, mSelectionComparator)) {
+                                selectionResultValue = selectionValue;
+                                selectionResult = uid;
+                            }
+                        });
+                    }
+                    readEntity(selectionResult, [&, this](const QByteArray &uid, const Sink::EntityBuffer &entityBuffer) {
+                        callback(Sink::Operation_Creation, uid, entityBuffer);
+                        foundValue = true;
+                    });
+                }
+                return false;
+            }))
+        {}
+        return foundValue;
+    }
+};
 
 DataStoreQuery::DataStoreQuery(const Sink::Query &query, const QByteArray &type, Sink::Storage::Transaction &transaction, TypeIndex &typeIndex, std::function<QVariant(const Sink::Entity &entity, const QByteArray &property)> getProperty)
     : mQuery(query), mTransaction(transaction), mType(type), mTypeIndex(typeIndex), mDb(Storage::mainDatabase(mTransaction, mType)), mGetProperty(getProperty)
@@ -230,6 +257,11 @@ QVariant DataStoreQuery::getProperty(const Sink::Entity &entity, const QByteArra
     return mGetProperty(entity, property);
 }
 
+QVector<QByteArray> DataStoreQuery::indexLookup(const QByteArray &property, const QVariant &value)
+{
+    return mTypeIndex.lookup(property, value, mTransaction);
+}
+
 /* ResultSet DataStoreQuery::filterAndSortSet(ResultSet &resultSet, const FilterFunction &filter, const QByteArray &sortProperty) */
 /* { */
 /*     const bool sortingRequired = !sortProperty.isEmpty(); */
@@ -347,11 +379,10 @@ void DataStoreQuery::setupQuery()
     /*     baseSet = Sort::Ptr::create(baseSet, mQuery.sortProperty); */
     /* } */
 
-    /* if (mQuery.threadLeaderOnly) { */
-    /*     auto reduce = Reduce::Ptr::create(baseSet, this); */
-
-    /*     baseSet = reduce; */
-    /* } */
+    if (mQuery.threadLeaderOnly) {
+        auto reduce = Reduce::Ptr::create("threadId", "date", Reduce::Max, baseSet, this);
+        baseSet = reduce;
+    }
 
     mCollector = Collector::Ptr::create(baseSet, this);
 }
-- 
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