From 5dc14c88f9510795835fb4f0a0d46d67c40f7020 Mon Sep 17 00:00:00 2001
From: Ulf Hermann <ulf.hermann@qt.io>
Date: Tue, 2 Jun 2020 16:50:20 +0200
Subject: Allow QML plugins to be optional

If a plugin does nothing but load the library that provides the types,
we can skip the plugin loading by linking the library directly. State
that in the qmldir file, and evaluate it when loading the module.

Task-number: QTBUG-84639
Change-Id: I2097237866a50f66c55e4653ad119fe10e18a893
Reviewed-by: Paul Wicking <paul.wicking@qt.io>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
---
 src/qml/qml/qqmlmetatype.cpp | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

(limited to 'src/qml/qml/qqmlmetatype.cpp')

diff --git a/src/qml/qml/qqmlmetatype.cpp b/src/qml/qml/qqmlmetatype.cpp
index 61e8e323c6..fd307e4575 100644
--- a/src/qml/qml/qqmlmetatype.cpp
+++ b/src/qml/qml/qqmlmetatype.cpp
@@ -681,9 +681,9 @@ public:
 };
 
 
-bool QQmlMetaType::registerPluginTypes(QObject *instance, const QString &basePath,
-                                       const QString &uri, const QString &typeNamespace,
-                                       QTypeRevision version, QList<QQmlError> *errors)
+QQmlMetaType::RegistrationResult QQmlMetaType::registerPluginTypes(
+        QObject *instance, const QString &basePath, const QString &uri,
+        const QString &typeNamespace, QTypeRevision version, QList<QQmlError> *errors)
 {
     if (!typeNamespace.isEmpty() && typeNamespace != uri) {
         // This is an 'identified' module
@@ -695,7 +695,7 @@ bool QQmlMetaType::registerPluginTypes(QObject *instance, const QString &basePat
                             .arg(typeNamespace).arg(uri));
             errors->prepend(error);
         }
-        return false;
+        return RegistrationResult::Failure;
     }
 
     QStringList failures;
@@ -713,7 +713,7 @@ bool QQmlMetaType::registerPluginTypes(QObject *instance, const QString &basePat
                                                  .arg(typeNamespace));
                     errors->prepend(error);
                 }
-                return false;
+                return RegistrationResult::Failure;
             }
         } else {
             // This is not an identified module - provide a warning
@@ -722,7 +722,7 @@ bool QQmlMetaType::registerPluginTypes(QObject *instance, const QString &basePat
                                    "it cannot be protected from external registrations.").arg(uri));
         }
 
-        if (!qobject_cast<QQmlEngineExtensionInterface *>(instance)) {
+        if (instance && !qobject_cast<QQmlEngineExtensionInterface *>(instance)) {
             QQmlTypesExtensionInterface *iface = qobject_cast<QQmlTypesExtensionInterface *>(instance);
             if (!iface) {
                 if (errors) {
@@ -732,7 +732,7 @@ bool QQmlMetaType::registerPluginTypes(QObject *instance, const QString &basePat
                                                         "QQmlEngineExtensionInterface").arg(typeNamespace));
                     errors->prepend(error);
                 }
-                return false;
+                return RegistrationResult::Failure;
             }
 
             if (auto *plugin = qobject_cast<QQmlExtensionPlugin *>(instance)) {
@@ -746,7 +746,8 @@ bool QQmlMetaType::registerPluginTypes(QObject *instance, const QString &basePat
             iface->registerTypes(moduleId);
         }
 
-        data->registerModuleTypes(uri);
+        if (failures.isEmpty() && !data->registerModuleTypes(uri))
+            return RegistrationResult::NoRegistrationFunction;
 
         if (!failures.isEmpty()) {
             if (errors) {
@@ -756,11 +757,11 @@ bool QQmlMetaType::registerPluginTypes(QObject *instance, const QString &basePat
                     errors->prepend(error);
                 }
             }
-            return false;
+            return RegistrationResult::Failure;
         }
     }
 
-    return true;
+    return RegistrationResult::Success;
 }
 
 /*
-- 
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