QPluginLoader: pave the way for Qt 6 plugin meta data

We want to store the metadata size and get it from the plugin in Qt 6.

Change-Id: Ieb48f7c0dd0e4e0fb35efffd153bebc2914d9a3c
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

src/corelib/plugin/qplugin.h

@@ -1,6 +1,7 @@
 /****************************************************************************
 **
 ** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2018 Intel Corporation.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtCore module of the Qt Toolkit.
@@ -56,13 +57,27 @@ QT_BEGIN_NAMESPACE
 #endif
 
 typedef QObject *(*QtPluginInstanceFunction)();
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
 typedef const char *(*QtPluginMetaDataFunction)();
+#else
+typedef QPair<const uchar *, size_t> (*QtPluginMetaDataFunction)();
+#endif
+
 
 struct Q_CORE_EXPORT QStaticPlugin
 {
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+public:
+    constexpr QStaticPlugin(QtPluginInstanceFunction i, QtPluginMetaDataFunction m)
+        : instance(i), rawMetaData(m().first), rawMetaDataSize(m().second)
+    QtPluginInstanceFunction instance;
+private:
+    // ### Qt 6: revise, as this is not standard-layout
+    const void *rawMetaData;
+    qsizetype rawMetaDataSize
+#elif !defined(Q_QDOC)
     // Note: This struct is initialized using an initializer list.
     // As such, it cannot have any new constructors or variables.
-#ifndef Q_QDOC
     QtPluginInstanceFunction instance;
     QtPluginMetaDataFunction rawMetaData;
 #else
@@ -133,6 +148,15 @@ void Q_CORE_EXPORT qRegisterStaticPluginFunction(QStaticPlugin staticPlugin);
         return plugin; \
     }
 
+#elif QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+
+#  define QT_MOC_EXPORT_PLUGIN(PLUGINCLASS, PLUGINCLASSNAME)      \
+            Q_EXTERN_C Q_DECL_EXPORT \
+            auto qt_plugin_query_metadata() \
+            { return qMakePair<const void *, size_t>(qt_pluginMetaData, sizeof qt_pluginMetaData); } \
+            Q_EXTERN_C Q_DECL_EXPORT QT_PREPEND_NAMESPACE(QObject) *qt_plugin_instance() \
+            Q_PLUGIN_INSTANCE(PLUGINCLASS)
+
 #else
 
 #  define QT_MOC_EXPORT_PLUGIN(PLUGINCLASS, PLUGINCLASSNAME)      \

tests/auto/corelib/plugin/qpluginloader/qpluginloader.pro

@@ -3,6 +3,7 @@ TEMPLATE = subdirs
 
 tst.depends = lib theplugin
 SUBDIRS = lib \
+          staticplugin \
           theplugin \
           tst
 !android:!win32:!darwin {

tests/auto/corelib/plugin/qpluginloader/staticplugin/.gitignore

@@ -0,0 +1,3 @@
+*staticplugin.prl
+libstaticplugin.a
+staticplugin.lib

tests/auto/corelib/plugin/qpluginloader/staticplugin/main.cpp

@@ -0,0 +1,39 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 Intel Corporation.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+#include <QtPlugin>
+#include <QObject>
+
+class StaticPlugin : public QObject
+{
+    Q_OBJECT
+    Q_PLUGIN_METADATA(IID "SomeIID")
+public:
+    StaticPlugin() {}
+};
+
+#include "main.moc"

tests/auto/corelib/plugin/qpluginloader/staticplugin/staticplugin.pro

@@ -0,0 +1,7 @@
+TEMPLATE = lib
+CONFIG += plugin static
+SOURCES = main.cpp
+QT = core
+
+# Add extra metadata to the plugin
+QMAKE_MOC_OPTIONS += -M ExtraMetaData=StaticPlugin -M ExtraMetaData=foo

tests/auto/corelib/plugin/qpluginloader/tst/tst.pro

@@ -8,9 +8,14 @@ HEADERS = ../theplugin/plugininterface.h
 win32 {
     CONFIG(debug, debug|release) {
         TARGET = ../../debug/tst_qpluginloader
+        LIBS += -L../staticplugin/debug
     } else {
         TARGET = ../../release/tst_qpluginloader
+        LIBS += -L../staticplugin/release
     }
+} else {
+    LIBS += -L../staticplugin
 }
+LIBS += -lstaticplugin
 
 TESTDATA += ../elftest ../machtest

tests/auto/corelib/plugin/qpluginloader/tst_qpluginloader.cpp

@@ -1,7 +1,7 @@
 /****************************************************************************
 **
 ** Copyright (C) 2016 The Qt Company Ltd.
-** Copyright (C) 2016 Intel Corporation.
+** Copyright (C) 2018 Intel Corporation.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the test suite of the Qt Toolkit.
@@ -121,8 +121,11 @@ private slots:
     void reloadPlugin();
     void preloadedPlugin_data();
     void preloadedPlugin();
+    void staticPlugins();
 };
 
+Q_IMPORT_PLUGIN(StaticPlugin)
+
 void tst_QPluginLoader::cleanup()
 {
     // check if the library/plugin was leaked
@@ -512,5 +515,37 @@ void tst_QPluginLoader::preloadedPlugin()
     QVERIFY(lib.unload());
 }
 
+void tst_QPluginLoader::staticPlugins()
+{
+    const QObjectList instances = QPluginLoader::staticInstances();
+    QVERIFY(instances.size());
+
+    bool found = false;
+    for (QObject *obj : instances) {
+        found = obj->metaObject()->className() == QLatin1String("StaticPlugin");
+        if (found)
+            break;
+    }
+    QVERIFY(found);
+
+    const auto plugins = QPluginLoader::staticPlugins();
+    QCOMPARE(plugins.size(), instances.size());
+
+    // find the metadata
+    QJsonObject metaData;
+    for (const auto &p : plugins) {
+        metaData = p.metaData();
+        found = metaData.value("className").toString() == QLatin1String("StaticPlugin");
+        if (found)
+            break;
+    }
+    QVERIFY(found);
+
+    QCOMPARE(metaData.value("version").toInt(), QT_VERSION);
+    QCOMPARE(metaData.value("IID").toString(), "SomeIID");
+    QCOMPARE(metaData.value("ExtraMetaData"), QJsonArray({ "StaticPlugin", "foo" }));
+}
+
+
 QTEST_MAIN(tst_QPluginLoader)
 #include "tst_qpluginloader.moc"