QPluginLoader: add 'staticPlugins' function

Currently there is no API to extract the meta data
from static plugins. This is needed in e.g QtDeclarative
for loading static module plugins.

This patch moves the 'staticPlugins' function from
QLibraryPrivate into QPluginLoader, and makes it public.
As such, we now also export QStaticPlugin.
Since an application developer cannot do much with raw
metadata, we add a new function
QStaticPlugin::metaData() that returns the QJsonObject
for the plugin. The old metaData function is
renamed 'rawMetaData'.

Change-Id: Idb0bf9ad8ebb13340565512e1998b26e762a357e
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

5 files changed, 66 insertions, 15 deletions

diff --git a/src/corelib/plugin/qfactoryloader.cpp b/src/corelib/plugin/qfactoryloader.cpp
index 3c8e00519b..a3e809a266 100644
--- a/src/corelib/plugin/qfactoryloader.cpp
+++ b/src/corelib/plugin/qfactoryloader.cpp
@@ -235,13 +235,10 @@ QList<QJsonObject> QFactoryLoader::metaData() const
     for (int i = 0; i < d->libraryList.size(); ++i)
         metaData.append(d->libraryList.at(i)->metaData);
 
-    QVector<QStaticPlugin> staticPlugins = QLibraryPrivate::staticPlugins();
-    for (int i = 0; i < staticPlugins.count(); ++i) {
-        const char *rawMetaData = staticPlugins.at(i).metaData();
-        QJsonObject object = QLibraryPrivate::fromRawMetaData(rawMetaData).object();
+    foreach (const QStaticPlugin &plugin, QPluginLoader::staticPlugins()) {
+        const QJsonObject object = plugin.metaData();
         if (object.value(QLatin1String("IID")) != QLatin1String(d->iid.constData(), d->iid.size()))
             continue;
-
         metaData.append(object);
     }
     return metaData;
@@ -269,10 +266,9 @@ QObject *QFactoryLoader::instance(int index) const
     }
 
     index -= d->libraryList.size();
-    QVector<QStaticPlugin> staticPlugins = QLibraryPrivate::staticPlugins();
+    QVector<QStaticPlugin> staticPlugins = QPluginLoader::staticPlugins();
     for (int i = 0; i < staticPlugins.count(); ++i) {
-        const char *rawMetaData = staticPlugins.at(i).metaData();
-        QJsonObject object = QLibraryPrivate::fromRawMetaData(rawMetaData).object();
+        const QJsonObject object = staticPlugins.at(i).metaData();
         if (object.value(QLatin1String("IID")) != QLatin1String(d->iid.constData(), d->iid.size()))
             continue;
 
diff --git a/src/corelib/plugin/qlibrary_p.h b/src/corelib/plugin/qlibrary_p.h
index abf11be9f7..20b0c7e20f 100644
--- a/src/corelib/plugin/qlibrary_p.h
+++ b/src/corelib/plugin/qlibrary_p.h
@@ -98,9 +98,6 @@ public:
     static QStringList suffixes_sys(const QString &fullVersion);
     static QStringList prefixes_sys();
 
-    static QVector<QStaticPlugin> staticPlugins();
-
-
     QPointer<QObject> inst;
     QtPluginInstanceFunction instance;
     QJsonObject metaData;
diff --git a/src/corelib/plugin/qplugin.h b/src/corelib/plugin/qplugin.h
index b91a0e9900..1ec9325e5e 100644
--- a/src/corelib/plugin/qplugin.h
+++ b/src/corelib/plugin/qplugin.h
@@ -44,6 +44,7 @@
 
 #include <QtCore/qobject.h>
 #include <QtCore/qpointer.h>
+#include <QtCore/qjsonobject.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -59,11 +60,22 @@ QT_BEGIN_NAMESPACE
 typedef QObject *(*QtPluginInstanceFunction)();
 typedef const char *(*QtPluginMetaDataFunction)();
 
-struct QStaticPlugin
+struct Q_CORE_EXPORT QStaticPlugin
 {
+    // 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 metaData;
+    QtPluginMetaDataFunction rawMetaData;
+#else
+    // Since qdoc gets confused by the use of function
+    // pointers, we add these dummes for it to parse instead:
+    QObject *instance();
+    const char *rawMetaData();
+#endif
+    QJsonObject metaData() const;
 };
+Q_DECLARE_TYPEINFO(QStaticPlugin, Q_PRIMITIVE_TYPE);
 
 void Q_CORE_EXPORT qRegisterStaticPluginFunction(QStaticPlugin staticPlugin);
 
diff --git a/src/corelib/plugin/qpluginloader.cpp b/src/corelib/plugin/qpluginloader.cpp
index 5a59942aad..46844acb01 100644
--- a/src/corelib/plugin/qpluginloader.cpp
+++ b/src/corelib/plugin/qpluginloader.cpp
@@ -107,6 +107,33 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
+    \class QStaticPlugin
+    \inmodule QtCore
+    \since 5.2
+
+    \brief QStaticPlugin is a struct containing a reference to a
+    static plugin instance together with its meta data.
+
+    \sa QPluginLoader, {How to Create Qt Plugins}
+*/
+
+/*!
+    \fn QObject *QStaticPlugin::instance()
+
+    Returns the plugin instance.
+
+    \sa QPluginLoader::staticInstances()
+*/
+
+/*!
+    \fn const char *QStaticPlugin::rawMetaData()
+
+    Returns the raw meta data for the plugin.
+
+    \sa metaData(), Q_PLUGIN_METADATA()
+*/
+
+/*!
     Constructs a plugin loader with the given \a parent.
 */
 QPluginLoader::QPluginLoader(QObject *parent)
@@ -407,6 +434,7 @@ void Q_CORE_EXPORT qRegisterStaticPluginFunction(QStaticPlugin plugin)
 /*!
     Returns a list of static plugin instances (root components) held
     by the plugin loader.
+    \sa staticPlugins()
 */
 QObjectList QPluginLoader::staticInstances()
 {
@@ -419,8 +447,14 @@ QObjectList QPluginLoader::staticInstances()
     return instances;
 }
 
-
-QVector<QStaticPlugin> QLibraryPrivate::staticPlugins()
+/*!
+    Returns a list of QStaticPlugins held by the plugin
+    loader. The function is similar to \l staticInstances()
+    with the addition that a QStaticPlugin also contains
+    meta data information.
+    \sa staticInstances()
+*/
+QVector<QStaticPlugin> QPluginLoader::staticPlugins()
 {
     StaticPluginList *plugins = staticPluginList();
     if (plugins)
@@ -428,6 +462,16 @@ QVector<QStaticPlugin> QLibraryPrivate::staticPlugins()
     return QVector<QStaticPlugin>();
 }
 
+/*!
+    Returns a the meta data for the plugin as a QJsonObject.
+
+    \sa rawMetaData()
+*/
+QJsonObject QStaticPlugin::metaData() const
+{
+    return QLibraryPrivate::fromRawMetaData(rawMetaData()).object();
+}
+
 QT_END_NAMESPACE
 
 #endif // QT_NO_LIBRARY
diff --git a/src/corelib/plugin/qpluginloader.h b/src/corelib/plugin/qpluginloader.h
index 8f8833e839..88c8ba4fa0 100644
--- a/src/corelib/plugin/qpluginloader.h
+++ b/src/corelib/plugin/qpluginloader.h
@@ -43,6 +43,7 @@
 #define QPLUGINLOADER_H
 
 #include <QtCore/qlibrary.h>
+#include <QtCore/qplugin.h>
 
 #ifndef QT_NO_LIBRARY
 
@@ -65,6 +66,7 @@ public:
     QJsonObject metaData() const;
 
     static QObjectList staticInstances();
+    static QVector<QStaticPlugin> staticPlugins();
 
     bool load();
     bool unload();