QFactoryLoader: Add API for supporting the metadata containing keys.

- Add a method returning a QMultiMap<int index, QString key>
  to QFactoryLoader, determined from metadata(), correctly
  reflecting the data structure ('Keys' being a list)
- Add convenience templates to create plugins via factory
  interfaces

Change-Id: I247749aa3245f635e476605db1c4cd9c74b74dea
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>

src/corelib/plugin/qfactoryloader.cpp

@@ -370,6 +370,39 @@ void QFactoryLoader::refreshAll()
     }
 }
 
+QMultiMap<int, QString> QFactoryLoader::keyMap() const
+{
+    QMultiMap<int, QString> result;
+    const QString metaDataKey = QStringLiteral("MetaData");
+    const QString keysKey = QStringLiteral("Keys");
+    const QList<QJsonObject> metaDataList = metaData();
+    for (int i = 0; i < metaDataList.size(); ++i) {
+        const QJsonObject metaData = metaDataList.at(i).value(metaDataKey).toObject();
+        const QJsonArray keys = metaData.value(keysKey).toArray();
+        const int keyCount = keys.size();
+        for (int k = 0; k < keyCount; ++k)
+            result.insert(i, keys.at(k).toString());
+    }
+    return result;
+}
+
+int QFactoryLoader::indexOf(const QString &needle) const
+{
+    const QString metaDataKey = QStringLiteral("MetaData");
+    const QString keysKey = QStringLiteral("Keys");
+    const QList<QJsonObject> metaDataList = metaData();
+    for (int i = 0; i < metaDataList.size(); ++i) {
+        const QJsonObject metaData = metaDataList.at(i).value(metaDataKey).toObject();
+        const QJsonArray keys = metaData.value(keysKey).toArray();
+        const int keyCount = keys.size();
+        for (int k = 0; k < keyCount; ++k) {
+            if (!keys.at(k).toString().compare(needle, Qt::CaseInsensitive))
+                return i;
+        }
+    }
+    return -1;
+}
+
 QT_END_NAMESPACE
 
 #endif // QT_NO_LIBRARY

src/corelib/plugin/qfactoryloader_p.h

@@ -56,6 +56,7 @@
 #include "QtCore/qobject.h"
 #include "QtCore/qstringlist.h"
 #include "QtCore/qjsonobject.h"
+#include "QtCore/qmap.h"
 #include "private/qlibrary_p.h"
 #ifndef QT_NO_LIBRARY
 
@@ -84,11 +85,42 @@ public:
     QLibraryPrivate *library(const QString &key) const;
 #endif
 
+    QMultiMap<int, QString> keyMap() const;
+    int indexOf(const QString &needle) const;
+
     void update();
 
     static void refreshAll();
 };
 
+template <class PluginInterface, class FactoryInterface>
+    PluginInterface *qLoadPlugin(const QFactoryLoader *loader, const QString &key)
+{
+    const int index = loader->indexOf(key);
+    if (index != -1) {
+        QObject *factoryObject = loader->instance(index);
+        if (FactoryInterface *factory = qobject_cast<FactoryInterface *>(factoryObject))
+            if (PluginInterface *result = factory->create(key))
+                return result;
+    }
+    return 0;
+}
+
+template <class PluginInterface, class FactoryInterface, class Parameter1>
+PluginInterface *qLoadPlugin1(const QFactoryLoader *loader,
+                              const QString &key,
+                              const Parameter1 &parameter1)
+{
+    const int index = loader->indexOf(key);
+    if (index != -1) {
+        QObject *factoryObject = loader->instance(index);
+        if (FactoryInterface *factory = qobject_cast<FactoryInterface *>(factoryObject))
+            if (PluginInterface *result = factory->create(key, parameter1))
+                return result;
+    }
+    return 0;
+}
+
 QT_END_NAMESPACE
 
 #endif // QT_NO_LIBRARY