Add templated module api registration function

This commit adds a templated module api registration function which
allows clients to provide type information at registration time.
We use this typeinformation in V4 if available, in order to allow
module APIs to be used in v4 bindings.

This commit also clarifies the ownership semantics of QObject module
apis, and updates some documentation references which were missed
during the rename of Declarative to Qml.

Task-number: QTBUG-24894
Change-Id: Iebb61ca8d8eacbb15218549eab715e22f52a1474
Reviewed-by: Michael Brasser <michael.brasser@nokia.com>

7 files changed, 42 insertions, 17 deletions

diff --git a/src/imports/localstorage/plugin.cpp b/src/imports/localstorage/plugin.cpp
index 0187d06e6a..4f08e71fd0 100644
--- a/src/imports/localstorage/plugin.cpp
+++ b/src/imports/localstorage/plugin.cpp
@@ -661,7 +661,7 @@ public:
     void registerTypes(const char *uri)
     {
         Q_ASSERT(QLatin1String(uri) == "QtQuick.LocalStorage");
-        qmlRegisterModuleApi(uri, 2, 0, module_api_factory);
+        qmlRegisterModuleApi<QQuickLocalStorage>(uri, 2, 0, module_api_factory);
     }
 };
 
diff --git a/src/qml/qml/qqml.h b/src/qml/qml/qqml.h
index 32da2c616e..5b500e0814 100644
--- a/src/qml/qml/qqml.h
+++ b/src/qml/qml/qqml.h
@@ -421,7 +421,7 @@ inline int qmlRegisterModuleApi(const char *uri, int versionMajor, int versionMi
 
         uri, versionMajor, versionMinor,
 
-        callback, 0
+        callback, 0, 0
     };
 
     return QQmlPrivate::qmlregister(QQmlPrivate::ModuleApiRegistration, &api);
@@ -435,7 +435,22 @@ inline int qmlRegisterModuleApi(const char *uri, int versionMajor, int versionMi
 
         uri, versionMajor, versionMinor,
 
-        0, callback
+        0, callback, 0 // unknown QObject instance type
+    };
+
+    return QQmlPrivate::qmlregister(QQmlPrivate::ModuleApiRegistration, &api);
+}
+
+template <typename T>
+inline int qmlRegisterModuleApi(const char *uri, int versionMajor, int versionMinor,
+                                QObject *(*callback)(QQmlEngine *, QJSEngine *))
+{
+    QQmlPrivate::RegisterModuleApi api = {
+        1,
+
+        uri, versionMajor, versionMinor,
+
+        0, callback, &T::staticMetaObject
     };
 
     return QQmlPrivate::qmlregister(QQmlPrivate::ModuleApiRegistration, &api);
diff --git a/src/qml/qml/qqmlengine.cpp b/src/qml/qml/qqmlengine.cpp
index 489b4f895a..3d09ebb83f 100644
--- a/src/qml/qml/qqmlengine.cpp
+++ b/src/qml/qml/qqmlengine.cpp
@@ -1701,6 +1701,7 @@ QQmlEnginePrivate::moduleApiInstance(const QQmlMetaType::ModuleApi &module)
         a = new QQmlMetaType::ModuleApiInstance;
         a->scriptCallback = module.script;
         a->qobjectCallback = module.qobject;
+        a->instanceMetaObject = module.instanceMetaObject;
         moduleApiInstances.insert(module, a);
     }
 
diff --git a/src/qml/qml/qqmlmetatype.cpp b/src/qml/qml/qqmlmetatype.cpp
index 985adbfec7..d4c19f8325 100644
--- a/src/qml/qml/qqmlmetatype.cpp
+++ b/src/qml/qml/qqmlmetatype.cpp
@@ -913,6 +913,10 @@ int registerModuleApi(const QQmlPrivate::RegisterModuleApi &api)
     import.minor = api.versionMinor;
     import.script = api.scriptApi;
     import.qobject = api.qobjectApi;
+    import.instanceMetaObject = (api.qobjectApi && api.version >= 1) ? api.instanceMetaObject : 0; // BC with version 0.
+
+    if (import.qobject && !import.instanceMetaObject) // BC - check import.iMO rather than api.iMO.
+        qWarning() << "qmlRegisterModuleApi(): sub-optimal: use the templated version of this function instead!";
 
     int index = data->moduleApiCount++;
 
diff --git a/src/qml/qml/qqmlmetatype_p.h b/src/qml/qml/qqmlmetatype_p.h
index b715d0c8f2..03017cafab 100644
--- a/src/qml/qml/qqmlmetatype_p.h
+++ b/src/qml/qml/qqmlmetatype_p.h
@@ -115,20 +115,23 @@ public:
 
     struct ModuleApiInstance {
         ModuleApiInstance()
-            : scriptCallback(0), qobjectCallback(0), qobjectApi(0) {}
+            : scriptCallback(0), qobjectCallback(0), qobjectApi(0), instanceMetaObject(0) {}
 
         QJSValue (*scriptCallback)(QQmlEngine *, QJSEngine *);
         QObject *(*qobjectCallback)(QQmlEngine *, QJSEngine *);
-        QJSValue scriptApi;
         QObject *qobjectApi;
+        const QMetaObject *instanceMetaObject;
+        QJSValue scriptApi;
+
     };
     struct ModuleApi {
         inline ModuleApi();
         inline bool operator==(const ModuleApi &) const;
         int major;
         int minor;
-        QJSValue (*script)(QQmlEngine *, QJSEngine *);
         QObject *(*qobject)(QQmlEngine *, QJSEngine *);
+        const QMetaObject *instanceMetaObject;
+        QJSValue (*script)(QQmlEngine *, QJSEngine *);
     };
     static ModuleApi moduleApi(const QString &, int, int);
     static QHash<QString, QList<ModuleApi> > moduleApis();
@@ -247,8 +250,9 @@ QQmlMetaType::ModuleApi::ModuleApi()
 {
     major = 0;
     minor = 0;
-    script = 0;
     qobject = 0;
+    instanceMetaObject = 0;
+    script = 0;
 }
 
 bool QQmlMetaType::ModuleApi::operator==(const ModuleApi &other) const
diff --git a/src/qml/qml/qqmlprivate.h b/src/qml/qml/qqmlprivate.h
index b4c6fc3a12..82da62ff45 100644
--- a/src/qml/qml/qqmlprivate.h
+++ b/src/qml/qml/qqmlprivate.h
@@ -246,6 +246,7 @@ namespace QQmlPrivate
 
         QJSValue (*scriptApi)(QQmlEngine *, QJSEngine *);
         QObject *(*qobjectApi)(QQmlEngine *, QJSEngine *);
+        const QMetaObject *instanceMetaObject;
     };
 
     enum RegistrationType {
diff --git a/src/qml/qml/v4/qv4irbuilder.cpp b/src/qml/qml/v4/qv4irbuilder.cpp
index ea4d1afbbc..453120c6c7 100644
--- a/src/qml/qml/v4/qv4irbuilder.cpp
+++ b/src/qml/qml/v4/qv4irbuilder.cpp
@@ -428,18 +428,18 @@ bool QV4IRBuilder::visit(AST::IdentifierExpression *ast)
         if (r.isValid()) {
             if (r.type) {
                 _expr.code = _block->ATTACH_TYPE(name, r.type, IR::Name::ScopeStorage, line, column);
-            } /*else if (r.importNamespace) {
+            } else if (r.importNamespace) {
                 QQmlMetaType::ModuleApiInstance *moduleApi = m_expression->importCache->moduleApi(r.importNamespace);
-                if (moduleApi) {
-                    if (moduleApi->qobjectCallback) {
-                        moduleApi->qobjectApi = moduleApi->qobjectCallback(QQmlEnginePrivate::get(m_engine), QQmlEnginePrivate::get(m_engine));
-                        moduleApi->qobjectCallback = 0;
-                        moduleApi->scriptCallback = 0;
-                    }
-                    if (moduleApi->qobjectApi)
-                        _expr.code = _block->MODULE_OBJECT(name, moduleApi->qobjectApi->metaObject(), IR::Name::MemberStorage, line, column);
+                if (moduleApi && moduleApi->instanceMetaObject) {
+                    // Note: we don't need to check moduleApi->qobjectCallback here, since
+                    // we did that check in registerModuleApi() in qqmlmetatype.cpp.
+                    // We cannot create the QObject Module Api Instance here,
+                    // as we might be running in a loader thread.
+                    // Thus, V4 can only handle bindings which use Module APIs which
+                    // were registered with the templated registration function.
+                    _expr.code = _block->MODULE_OBJECT(name, moduleApi->instanceMetaObject, IR::Name::MemberStorage, line, column);
                 }
-            }*/ //### we can't create the actual QObject here, as we may be running in a thread (can be reenabled once QTBUG-24894 is handled)
+            }
             // We don't support anything else
         } else {
             bool found = false;