Updated Reduce

* Added sourceKeyFunction for determining source key as alternative to sourceKeyName
* If targetValueName is null, use whole object returned from
  add/subtract as result of reduce. This will be the only behavior
  once all Reduces are converted.
* Combined some redundant code in JsonDbReduceDefinition.
* Added basic Reduce documentation.

Change-Id: I258d9e24bb5fa620634b1168832ee4bbc1d58aca
Reviewed-by: Kevin Simons <kevin.simons@nokia.com>

6 files changed, 345 insertions, 77 deletions

diff --git a/doc/src/index.qdoc b/doc/src/index.qdoc
index 4026e8c..6e8842a 100644
--- a/doc/src/index.qdoc
+++ b/doc/src/index.qdoc
@@ -110,6 +110,7 @@ sets.
 
 \list
 \li \l {Map and Join Views}
+\li \l {Reduce Views}
 \endlist
 
 \section2 Notifications
@@ -134,6 +135,7 @@ See also \l{QJsonDbWatcher}
 \li \l{declarative/desktop-inspector}{Desktop Database Inspector Example}
 \li \l{declarative/map-phone}{Creating a Map View}
 \li \l{declarative/joinview}{Creating a Join View}
+\li \l{declarative/reduce-phone}{Creating a Reduce View}
 \li \l{client/chat}{Creating a chat client using the C++ API}
 \endlist
 */
diff --git a/doc/src/reduce-views.qdoc b/doc/src/reduce-views.qdoc
new file mode 100644
index 0000000..d16c5f9
--- /dev/null
+++ b/doc/src/reduce-views.qdoc
@@ -0,0 +1,136 @@
+/****************************************************************************
+**
+** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/
+**
+** This file is part of the documentation of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:FDL$
+** GNU Free Documentation License
+** Alternatively, this file may be used under the terms of the GNU Free
+** Documentation License version 1.3 as published by the Free Software
+** Foundation and appearing in the file included in the packaging of
+** this file.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms
+** and conditions contained in a signed written agreement between you
+** and Nokia.
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+/*!
+\page reduce-views.html
+\title Reduce Views
+
+\target reduce
+
+\section1 Performing a Reduce
+
+A reduce is defined by creating a \l Reduce object in the database. A
+Reduce operates on objects of a single source type, producing values
+of a single target type. A Reduce incrementally combines source
+objects with matching keys using JavaScript "add" and "subtract"
+functions.
+
+\table
+\row
+\li _type
+\li Reduce
+
+\row
+\li targetType
+\li The output type of this reduction. The target type must extend \l View.
+
+\row
+\li targetKeyName
+\li The name of the key property in the target objects. Defaults to "key" if unspecified.
+
+\row
+\li targetValueName (should be "null")
+
+\li The name of the value property in the target objects. Defaults to
+"value" if unspecified. If this is defined to be "null", then the
+object returned from the "add" and "subtract" functions is used as the
+whole target object. The old behavior is deprecated and will be
+removed.
+
+\row
+\li sourceType
+\li The type of the source objects used in this reduction
+
+\row
+\li sourceKeyName
+
+\li The name of the key property in the source objects. Defaults to
+"key" if unspecified. Exactly one of sourceKeyName and
+sourceKeyFunction must be specified.
+
+\row
+\li sourceKeyFunction
+
+\li A string that represents a JavaScript function that takes an
+object and returns the key value for that object.  Exactly one of
+sourceKeyName and sourceKeyFunction must be specified.
+
+\row
+\li add
+\li A string that evaluates to a Javascript function taking three arguments: keyValue, targetObject, sourceObject..
+
+\row
+\li subtract
+\li A string that evaluates to a Javascript function taking three arguments: keyValue, targetObject, sourceObject.
+\endtable
+
+
+\section2 Deterministic Uuids
+
+View objects created by Reduce are assigned a deterministic Uuid. If
+the "add" or "subtract" functions assign _uuid to the object they
+return, then that value is used as the uuid for the object. Otherwise,
+the view engine constructs an identifier string as follows:
+\code
+        var identifier = targetType + ":" + reduceDefinitionUuid + ":" + keyValue;
+        var uuid = jsondb.createUuidFromString(identifier);
+\endcode
+
+\section2 Theory of Operation
+
+When the view is updated, it operates on all of the source objects
+that were changed since the last time the view was updated.
+
+If a source object is created, the key is extracted from the object
+using either sourceKeyName or sourceKeyFunction. The "add" function is
+applied to three arguments: the key value, the previous target object
+for the key value or undefined, and the source object.
+
+If a source object is removed, the key is extracted from the object
+that was removed using either sourceKeyName or sourceKeyFunction. The
+"remove" function is applied to three arguments: the key value, the
+previous target object for the key value or undefined, and the source
+object.
+
+If a source object is updated, it is treated as a remove of the
+previous value and a creation of the new value, so there will be a
+call to the "subtract" function and then the "add" function.
+
+All of the changes are staged together during an update of the view to
+minimize the number of changes of target objects visible via
+notifications.
+
+\section2 Reduce Proxy
+
+When the map functions run, they have access to a jsondb proxy object with one method:
+
+\table
+\row
+\li \l {jsondb.createUuidFromString}{jsondb.createUuidFromString}(identifier)
+\endtable
+
+*/
diff --git a/src/daemon/jsondbreducedefinition.cpp b/src/daemon/jsondbreducedefinition.cpp
index f591fd5..1021413 100644
--- a/src/daemon/jsondbreducedefinition.cpp
+++ b/src/daemon/jsondbreducedefinition.cpp
@@ -73,11 +73,20 @@ JsonDbReduceDefinition::JsonDbReduceDefinition(const JsonDbOwner *owner, JsonDbP
     , mTargetType(mDefinition.value("targetType").toString())
     , mTargetTable(mPartition->findObjectTable(mTargetType))
     , mSourceType(mDefinition.value("sourceType").toString())
-    , mTargetKeyName(mDefinition.contains("targetKeyName") ? mDefinition.value("targetKeyName").toString() : QString("key"))
-    , mTargetValueName(mDefinition.contains("targetValueName") ? mDefinition.value("targetValueName").toString() : QString("value"))
-    , mSourceKeyName(mDefinition.contains("sourceKeyName") ? mDefinition.value("sourceKeyName").toString() : QString("key"))
-    , mSourceKeyNameList(mSourceKeyName.split("."))
 {
+    if (mDefinition.contains("targetKeyName"))
+        mTargetKeyName = mDefinition.value("targetKeyName").toString();
+    else
+        mTargetKeyName = QLatin1String("key");
+    if (mDefinition.contains("sourceKeyName"))
+        mSourceKeyName = mDefinition.value("sourceKeyName").toString();
+    mSourceKeyNameList = mSourceKeyName.split(".");
+    if (mDefinition.contains("targetValueName")) {
+        if (mDefinition.value("targetValueName").isString())
+            mTargetValueName = mDefinition.value("targetValueName").toString();
+    } else
+        mTargetValueName = QLatin1String("value");
+
 }
 
 void JsonDbReduceDefinition::definitionCreated()
@@ -115,7 +124,7 @@ void JsonDbReduceDefinition::initScriptEngine()
 
     mScriptEngine = new QJSEngine(this);
     QString message;
-    bool status = compileFunctions(mScriptEngine, mDefinition, mAddFunction, mSubtractFunction, message);
+    bool status = compileFunctions(mScriptEngine, mDefinition, mFunctions, message);
     if (!status)
         setError(message);
 
@@ -128,14 +137,19 @@ void JsonDbReduceDefinition::initScriptEngine()
 
 void JsonDbReduceDefinition::releaseScriptEngine()
 {
-    mAddFunction = QJSValue();
-    mSubtractFunction = QJSValue();
+    mFunctions.clear();
     delete mScriptEngine;
     mScriptEngine = 0;
 }
 
 void JsonDbReduceDefinition::initIndexes()
 {
+    // TODO: this index should not be automatic
+    if (!mSourceKeyName.isEmpty()) {
+        JsonDbObjectTable *sourceTable = mPartition->findObjectTable(mSourceType);
+        sourceTable->addIndexOnProperty(mSourceKeyName, QLatin1String("string"));
+    }
+    // TODO: this index should not be automatic
     mTargetTable->addIndexOnProperty(mTargetKeyName, QLatin1String("string"), mTargetType);
     mTargetTable->addIndexOnProperty(QLatin1String("_reduceUuid"), QLatin1String("string"), mTargetType);
 }
@@ -143,14 +157,9 @@ void JsonDbReduceDefinition::initIndexes()
 void JsonDbReduceDefinition::updateObject(JsonDbObject before, JsonDbObject after)
 {
     initScriptEngine();
-    Q_ASSERT(mAddFunction.isCallable());
 
-    QJsonValue beforeKeyValue = mSourceKeyName.contains(".")
-        ? before.propertyLookup(mSourceKeyNameList)
-        : before.value(mSourceKeyName);
-    QJsonValue afterKeyValue = mSourceKeyName.contains(".")
-        ? after.propertyLookup(mSourceKeyNameList)
-        : after.value(mSourceKeyName);
+    QJsonValue beforeKeyValue = sourceKeyValue(before);
+    QJsonValue afterKeyValue = sourceKeyValue(after);
 
     if (!after.isEmpty() && !before.isEmpty() && (beforeKeyValue != afterKeyValue)) {
         // do a subtract only on the before key
@@ -184,9 +193,9 @@ void JsonDbReduceDefinition::updateObject(JsonDbObject before, JsonDbObject afte
 
     QJsonValue value = previousValue;
     if (!before.isEmpty())
-        value = subtractObject(keyValue, value, before);
+        value = addObject(JsonDbReduceDefinition::Subtract, keyValue, value, before);
     if (!after.isEmpty())
-        value = addObject(keyValue, value, after);
+        value = addObject(JsonDbReduceDefinition::Add, keyValue, value, after);
 
     JsonDbWriteResult res;
     // if we had a previous object to reduce
@@ -222,21 +231,28 @@ void JsonDbReduceDefinition::updateObject(JsonDbObject before, JsonDbObject afte
         setError(QString("Error executing add function: %1").arg(res.message));
 }
 
-QJsonValue JsonDbReduceDefinition::addObject(const QJsonValue &keyValue, const QJsonValue &previousValue, JsonDbObject object)
+QJsonValue JsonDbReduceDefinition::addObject(JsonDbReduceDefinition::FunctionNumber functionNumber,
+                                             const QJsonValue &keyValue, QJsonValue previousValue, JsonDbObject object)
 {
     initScriptEngine();
     QJSValue svKeyValue = JsonDbObject::toJSValue(keyValue, mScriptEngine);
-    QJSValue svPreviousValue = JsonDbObject::toJSValue(previousValue.toObject().value(mTargetValueName), mScriptEngine);
+    if (!mTargetValueName.isEmpty())
+        previousValue = previousValue.toObject().value(mTargetValueName);
+    QJSValue svPreviousValue = JsonDbObject::toJSValue(previousValue, mScriptEngine);
     QJSValue svObject = JsonDbObject::toJSValue(object, mScriptEngine);
 
     QJSValueList reduceArgs;
     reduceArgs << svKeyValue << svPreviousValue << svObject;
-    QJSValue reduced = mAddFunction.call(reduceArgs);
+    QJSValue reduced = mFunctions[functionNumber].call(reduceArgs);
 
     if (!reduced.isUndefined() && !reduced.isError()) {
-        QJsonObject jsonReduced;
-        jsonReduced.insert(mTargetValueName, JsonDbObject::fromJSValue(reduced));
-        return jsonReduced;
+        QJsonValue jsonReduced = JsonDbObject::fromJSValue(reduced);
+        QJsonObject jsonReducedObject;
+        if (!mTargetValueName.isEmpty())
+            jsonReducedObject.insert(mTargetValueName, jsonReduced);
+        else
+            jsonReducedObject = jsonReduced.toObject();
+        return jsonReducedObject;
     } else {
 
         if (reduced.isError())
@@ -246,31 +262,6 @@ QJsonValue JsonDbReduceDefinition::addObject(const QJsonValue &keyValue, const Q
     }
 }
 
-QJsonValue JsonDbReduceDefinition::subtractObject(const QJsonValue &keyValue, const QJsonValue &previousValue, JsonDbObject object)
-{
-    initScriptEngine();
-    Q_ASSERT(mSubtractFunction.isCallable());
-
-    QJSValue svKeyValue = JsonDbObject::toJSValue(keyValue, mScriptEngine);
-    QJSValue svPreviousValue = JsonDbObject::toJSValue(previousValue.toObject().value(mTargetValueName),
-                                                       mScriptEngine);
-    QJSValue sv = JsonDbObject::toJSValue(object, mScriptEngine);
-
-    QJSValueList reduceArgs;
-    reduceArgs << svKeyValue << svPreviousValue << sv;
-    QJSValue reduced = mSubtractFunction.call(reduceArgs);
-
-    if (!reduced.isUndefined() && !reduced.isError()) {
-        QJsonObject jsonReduced;
-        jsonReduced.insert(mTargetValueName, JsonDbObject::fromJSValue(reduced));
-        return jsonReduced;
-    } else {
-        if (reduced.isError())
-            setError("Error executing subtract function: " + reduced.toString());
-        return QJsonValue(QJsonValue::Undefined);
-    }
-}
-
 bool JsonDbReduceDefinition::isActive() const
 {
     return !mDefinition.contains(JsonDbString::kActiveStr) || mDefinition.value(JsonDbString::kActiveStr).toBool();
@@ -302,45 +293,67 @@ bool JsonDbReduceDefinition::validateDefinition(const JsonDbObject &reduce, Json
              && view->mReduceDefinitionsBySource.value(sourceType)->uuid() != uuid)
         message = QString("duplicate Reduce definition on source %1 and target %2")
             .arg(sourceType).arg(targetType);
-    else if (reduce.value("sourceKeyName").toString().isEmpty())
-        message = QLatin1Literal("sourceKeyName property for Reduce not specified");
+    else if (reduce.value("sourceKeyName").toString().isEmpty() && reduce.value("sourceKeyFunction").toString().isEmpty())
+        message = QLatin1Literal("sourceKeyName or sourceKeyFunction must be provided for Reduce");
+    else if (!reduce.value("sourceKeyName").toString().isEmpty() && !reduce.value("sourceKeyFunction").toString().isEmpty())
+        message = QLatin1Literal("Only one of sourceKeyName and sourceKeyFunction may be provided for Reduce");
     else if (reduce.value("add").toString().isEmpty())
         message = QLatin1Literal("add function for Reduce not specified");
     else if (reduce.value("subtract").toString().isEmpty())
         message = QLatin1Literal("subtract function for Reduce not specified");
+    else if (reduce.contains("targetValueName")
+             && !(reduce.value("targetValueName").isString() || reduce.value("targetValueName").isNull()))
+        message = QLatin1Literal("targetValueName for Reduce must be a string or null");
     else {
         // FIXME: This is static because otherwise we leak memory per QJSEngine instance
         static QJSEngine *scriptEngine = new QJSEngine;
-        QJSValue addFunction, subtractFunction;
+        QVector<QJSValue> functions;
         // check for script errors
-        compileFunctions(scriptEngine, reduce, addFunction, subtractFunction, message);
+        compileFunctions(scriptEngine, reduce, functions, message);
         scriptEngine->collectGarbage();
     }
     return message.isEmpty();
 }
 
-bool JsonDbReduceDefinition::compileFunctions(QJSEngine *scriptEngine, QJsonObject definition, QJSValue &addFunction, QJSValue &subtractFunction, QString &message)
+bool JsonDbReduceDefinition::compileFunctions(QJSEngine *scriptEngine, QJsonObject definition,
+                                              QVector<QJSValue> &functions, QString &message)
 {
-    Q_ASSERT(!definition.value("add").toString().isEmpty());
-    Q_ASSERT(!definition.value("subtract").toString().isEmpty());
-    QString script = definition.value("add").toString();
-    QJSValue result = scriptEngine->evaluate(QString("var %1 = (%2); %1;").arg("add").arg(script));
-
-    if (result.isError() || !result.isCallable()) {
-        message = QString("Unable to parse add function: %1").arg(result.toString());
-        return false;
+    bool status = true;
+    QStringList functionNames = (QStringList()
+                                 << QLatin1String("add")
+                                 << QLatin1String("subtract")
+                                 << QLatin1String("sourceKeyFunction"));
+    int i = 0;
+    functions.resize(3);
+    foreach (const QString &functionName, functionNames) {
+        int functionNumber = i++;
+        if (!definition.contains(functionName))
+            continue;
+        QString script = definition.value(functionName).toString();
+        QJSValue result = scriptEngine->evaluate(QString("(%1)").arg(script));
+
+        if (result.isError() || !result.isCallable()) {
+            message = QString("Unable to parse add function: %1").arg(result.toString());
+            status = false;
+            continue;
+        }
+        functions[functionNumber] = result;
     }
-    addFunction = result;
+    return status;
+}
 
-    script = definition.value("subtract").toString();
-    result = scriptEngine->evaluate(QString("var %1 = (%2); %1;").arg("subtract").arg(script));
+QJsonValue JsonDbReduceDefinition::sourceKeyValue(const QJsonObject &object)
+{
+    if (object.isEmpty()) {
+        return QJsonValue(QJsonValue::Undefined);
+    } else if (mFunctions[JsonDbReduceDefinition::SourceKeyValue].isCallable()) {
+        QJSValueList args;
+        args << JsonDbObject::toJSValue(object, mScriptEngine);
+        QJsonValue keyValue = JsonDbObject::fromJSValue(mFunctions[JsonDbReduceDefinition::SourceKeyValue].call(args));
+        return keyValue;
+    } else
+        return mSourceKeyName.contains(".") ? JsonDbObject(object).propertyLookup(mSourceKeyNameList) : object.value(mSourceKeyName);
 
-    if (result.isError() || !result.isCallable()) {
-        message = QString("Unable to parse subtract function: %1").arg(result.toString());
-        return false;
-    }
-    subtractFunction = result;
-    return true;
 }
 
 QT_END_NAMESPACE_JSONDB
diff --git a/src/daemon/jsondbreducedefinition.h b/src/daemon/jsondbreducedefinition.h
index 6530a82..214153e 100644
--- a/src/daemon/jsondbreducedefinition.h
+++ b/src/daemon/jsondbreducedefinition.h
@@ -77,8 +77,6 @@ public:
     QStringList sourceKeyNameList() const { return mSourceKeyNameList; }
     bool isActive() const;
     QJsonObject definition() const { return mDefinition; }
-    const QJSValue &addFunction() const { return mAddFunction; }
-    const QJSValue &subtractFunction() const { return mSubtractFunction; }
     const JsonDbOwner *owner() const { return mOwner; }
 
     static void definitionRemoved(JsonDbPartition *partition, JsonDbObjectTable *table, const QString targetType, const QString &definitionUuid);
@@ -89,21 +87,27 @@ public:
     void initIndexes();
 
     void updateObject(JsonDbObject before, JsonDbObject after);
-    QJsonValue addObject(const QJsonValue &keyValue, const QJsonValue &previousResult, JsonDbObject object);
-    QJsonValue subtractObject(const QJsonValue &keyValue, const QJsonValue &previousResult, JsonDbObject object);
 
     void setError(const QString &errorMsg);
 
     static bool validateDefinition(const JsonDbObject &reduce, JsonDbPartition *partition, QString &message);
-    static bool compileFunctions(QJSEngine *scriptEngine, QJsonObject definition, QJSValue &addFunction, QJSValue &subFunction, QString &message);
+
+private:
+    enum FunctionNumber {
+        Add = 0,
+        Subtract = 1,
+        SourceKeyValue = 2
+    };
+    static bool compileFunctions(QJSEngine *scriptEngine, QJsonObject definition, QVector<QJSValue> &mFunctions, QString &message);
+    QJsonValue sourceKeyValue(const QJsonObject &object);
+    QJsonValue addObject(FunctionNumber fn, const QJsonValue &keyValue, QJsonValue previousResult, JsonDbObject object);
 
 private:
     const JsonDbOwner *mOwner;
     JsonDbPartition *mPartition;
     QJsonObject    mDefinition;
     QJSEngine *mScriptEngine;
-    QJSValue   mAddFunction;
-    QJSValue   mSubtractFunction;
+    QVector<QJSValue> mFunctions;
     QString        mUuid;
     QString        mTargetType;
     JsonDbObjectTable   *mTargetTable;
diff --git a/tests/auto/daemon/json/reduce.json b/tests/auto/daemon/json/reduce.json
index f95d4f1..5939fb7 100644
--- a/tests/auto/daemon/json/reduce.json
+++ b/tests/auto/daemon/json/reduce.json
@@ -20,6 +20,8 @@
     "targetKeyName": "firstName",
     "targetValueName": "count",
     "add": "function add (k, z, c) { if (!z) {z = 0}; z += 1; if (z) return z;}",
-    "subtract": "function subtract (k, z, c) { if (!z) {z = 0}; z -= 1; if (z) return z;}"
+    "subtract": "function subtract (k, z, c) { if (!z) {z = 0}; z -= 1; if (z) return z;}",
+    "addFlattened": "function add (k, z, c) { if (!z) {z = {count: 0}}; z.count += 1; if (z.count) return z;}",
+    "subtractFlattened": "function subtract (k, z, c) { if (!z) {z = {count: 0}}; z.count -= 1; if (z.count) return z;}"
   }
 ]
diff --git a/tests/auto/daemon/testjsondb.cpp b/tests/auto/daemon/testjsondb.cpp
index 3532faa..ac37b35 100644
--- a/tests/auto/daemon/testjsondb.cpp
+++ b/tests/auto/daemon/testjsondb.cpp
@@ -175,6 +175,8 @@ private slots:
     void mapSchemaViolation();
     void mapArrayConversion();
     void reduce();
+    void reduceFlattened();
+    void reduceSourceKeyFunction();
     void reduceRemoval();
     void reduceUpdate();
     void reduceDuplicate();
@@ -1556,6 +1558,17 @@ void TestJsonDb::reduceDefinitionInvalid()
     verifyErrorResult(res);
     QVERIFY(res.message.contains("View"));
 
+    // fail because targetValue name is not a string or null
+    reduceDefinition = JsonDbObject();
+    reduceDefinition.insert(JsonDbString::kTypeStr, QLatin1String("Reduce"));
+    reduceDefinition.insert("targetType", QLatin1String("MyViewType"));
+    reduceDefinition.insert("sourceType", QLatin1String("Contact"));
+    reduceDefinition.insert("add", QLatin1String("function add (k, z, c) { }"));
+    reduceDefinition.insert("subtract", QLatin1String("function subtract (k, z, c) { }"));
+    reduceDefinition.insert("targetValueName", true);
+    res = create(mOwner, reduceDefinition);
+    verifyErrorResult(res);
+
     //schemaRes.value("result").toObject()
     verifyGoodResult(remove(mOwner, schema));
 }
@@ -2182,6 +2195,104 @@ void TestJsonDb::reduce()
     mJsonDbPartition->removeIndex("MyContactCount");
 }
 
+void TestJsonDb::reduceFlattened()
+{
+    QJsonArray objects(readJsonFile(":/daemon/json/reduce-data.json").toArray());
+
+    JsonDbObjectList toDelete;
+    JsonDbObjectList reduces;
+
+    QHash<QString, int> firstNameCount;
+    for (int ii = 0; ii < objects.size(); ii++) {
+        JsonDbObject object(objects.at(ii).toObject());
+        JsonDbWriteResult result = create(mOwner, object);
+        verifyGoodResult(result);
+        firstNameCount[object.value("firstName").toString()]++;
+        toDelete.append(object);
+    }
+
+    objects = readJsonFile(":/daemon/json/reduce.json").toArray();
+    for (int ii = 0; ii < objects.size(); ii++) {
+        JsonDbObject object(objects.at(ii).toObject());
+        if (object.value(JsonDbString::kTypeStr).toString() == JsonDbString::kReduceTypeStr) {
+            object.insert(QLatin1String("add"), object.value(QLatin1String("addFlattened")));
+            object.insert(QLatin1String("subtract"), object.value(QLatin1String("subtractFlattened")));
+            // transitional behavior: null targetValueName indicates whole object is value of the Reduce
+            object.insert(QLatin1String("targetValueName"), QJsonValue(QJsonValue::Null));
+        }
+        JsonDbWriteResult result = create(mOwner, object);
+        verifyGoodResult(result);
+        if (object.value(JsonDbString::kTypeStr).toString() == "Reduce")
+            reduces.append(object);
+        else
+            toDelete.append(object);
+    }
+
+    JsonDbQueryResult queryResult = find(mOwner, QLatin1String("[?_type=\"MyContactCount\"]"));
+    verifyGoodQueryResult(queryResult);
+    QCOMPARE(queryResult.data.size(), firstNameCount.keys().count());
+
+    JsonDbObjectList data = queryResult.data;
+    for (int ii = 0; ii < data.size(); ii++) {
+        QCOMPARE((int)data.at(ii).value("count").toDouble(),
+                 firstNameCount[data.at(ii).value("firstName").toString()]);
+    }
+    for (int ii = 0; ii < reduces.size(); ii++)
+        verifyGoodResult(remove(mOwner, reduces.at(ii)));
+    for (int ii = 0; ii < toDelete.size(); ii++)
+        verifyGoodResult(remove(mOwner, toDelete.at(ii)));
+    mJsonDbPartition->removeIndex("MyContactCount");
+}
+
+void TestJsonDb::reduceSourceKeyFunction()
+{
+    QJsonArray objects(readJsonFile(":/daemon/json/reduce-data.json").toArray());
+
+    JsonDbObjectList toDelete;
+    JsonDbObjectList reduces;
+
+    QHash<QString, int> firstNameCount;
+    for (int ii = 0; ii < objects.size(); ii++) {
+        JsonDbObject object(objects.at(ii).toObject());
+        JsonDbWriteResult result = create(mOwner, object);
+        verifyGoodResult(result);
+        firstNameCount[object.value("firstName").toString()]++;
+        toDelete.append(object);
+    }
+
+    objects = readJsonFile(":/daemon/json/reduce.json").toArray();
+    for (int ii = 0; ii < objects.size(); ii++) {
+        JsonDbObject object(objects.at(ii).toObject());
+        if (object.value(JsonDbString::kTypeStr).toString() == JsonDbString::kReduceTypeStr) {
+            QString sourceKeyName = object.value(QLatin1String("sourceKeyName")).toString();
+            object.remove(QLatin1String("sourceKeyName"));
+            object.insert(QLatin1String("sourceKeyFunction"),
+                          QString("function (o) { return o.%1; }").arg(sourceKeyName));
+        }
+        JsonDbWriteResult result = create(mOwner, object);
+        verifyGoodResult(result);
+        if (object.value(JsonDbString::kTypeStr).toString() == "Reduce")
+            reduces.append(object);
+        else
+            toDelete.append(object);
+    }
+
+    JsonDbQueryResult queryResult = find(mOwner, QLatin1String("[?_type=\"MyContactCount\"]"));
+    verifyGoodQueryResult(queryResult);
+    QCOMPARE(queryResult.data.size(), firstNameCount.keys().count());
+
+    JsonDbObjectList data = queryResult.data;
+    for (int ii = 0; ii < data.size(); ii++) {
+        QCOMPARE((int)data.at(ii).value("count").toDouble(),
+                 firstNameCount[data.at(ii).value("firstName").toString()]);
+    }
+    for (int ii = 0; ii < reduces.size(); ii++)
+        verifyGoodResult(remove(mOwner, reduces.at(ii)));
+    for (int ii = 0; ii < toDelete.size(); ii++)
+        verifyGoodResult(remove(mOwner, toDelete.at(ii)));
+    mJsonDbPartition->removeIndex("MyContactCount");
+}
+
 void TestJsonDb::reduceRemoval()
 {
     QJsonArray objects(readJsonFile(":/daemon/json/reduce-data.json").toArray());