Revert "Make sure we load translations on the main thread."

This broke the build for projects which used ecm_create_qm_loader in
unusual ways. A better approach is coming, but won't be in e-c-m 5.16.

This reverts commit 009c480413910e8c1a18f4d1420f4a517ea606e6.

CCBUG: 346188
CCMAIL: release-team@kde.org
CCMAIL: kde-buildsystem@kde.org

2 files changed, 28 insertions, 75 deletions

diff --git a/modules/ECMPoQmTools.cmake b/modules/ECMPoQmTools.cmake
index 22258dc8..12bcf6b6 100644
--- a/modules/ECMPoQmTools.cmake
+++ b/modules/ECMPoQmTools.cmake
@@ -99,20 +99,9 @@ endfunction()
 
 
 function(ecm_create_qm_loader out_var catalog_name)
-    set(loader_cpp ${CMAKE_CURRENT_BINARY_DIR}/ECMQmLoader.cpp)
-    set(loader_moc ${CMAKE_CURRENT_BINARY_DIR}/ECMQmLoader.moc)
-
     # catalog_name is used in ECMQmLoader.cpp.in
-    configure_file(${ECM_MODULE_DIR}/ECMQmLoader.cpp.in "${loader_cpp}" @ONLY)
-    set(${out_var} "${${out_var}}" "${loader_cpp}" "${loader_moc}" PARENT_SCOPE)
-
-    # can't assume target has AUTOMOC turned on
-    if(NOT Qt5Core_FOUND)
-        find_package(Qt5Core)
-    endif()
-    if(Qt5Core_FOUND)
-        qt5_generate_moc("${loader_cpp}" "${loader_moc}")
-    endif()
+    configure_file(${ECM_MODULE_DIR}/ECMQmLoader.cpp.in ECMQmLoader.cpp @ONLY)
+    set(${out_var} ${${out_var}} ${CMAKE_CURRENT_BINARY_DIR}/ECMQmLoader.cpp PARENT_SCOPE)
 endfunction()
 
 
diff --git a/modules/ECMQmLoader.cpp.in b/modules/ECMQmLoader.cpp.in
index fc667ba2..423d1c93 100644
--- a/modules/ECMQmLoader.cpp.in
+++ b/modules/ECMQmLoader.cpp.in
@@ -32,77 +32,41 @@
  */
 #include <QCoreApplication>
 #include <QLocale>
-#include <QMetaObject>
 #include <QStandardPaths>
-#include <QThread>
 #include <QTranslator>
 
-namespace {
+#include <QDebug>
 
-    bool loadTranslation(const QString &localeDirName)
-    {
-        QString subPath = QStringLiteral("locale/") + localeDirName + QStringLiteral("/LC_MESSAGES/@catalog_name@.qm");
-        QString fullPath = QStandardPaths::locate(QStandardPaths::GenericDataLocation, subPath);
-        if (fullPath.isEmpty()) {
-            return false;
-        }
-        QTranslator *translator = new QTranslator(QCoreApplication::instance());
-        if (!translator->load(fullPath)) {
-            delete translator;
-            return false;
-        }
-        QCoreApplication::instance()->installTranslator(translator);
-        return true;
+static bool loadTranslation(const QString &localeDirName)
+{
+    QString subPath = QStringLiteral("locale/") + localeDirName + QStringLiteral("/LC_MESSAGES/@catalog_name@.qm");
+    QString fullPath = QStandardPaths::locate(QStandardPaths::GenericDataLocation, subPath);
+    if (fullPath.isEmpty()) {
+        return false;
     }
-
-    void load()
-    {
-        // The way Qt translation system handles plural forms makes it necessary to
-        // have a translation file which contains only plural forms for `en`. That's
-        // why we load the `en` translation unconditionally, then load the
-        // translation for the current locale to overload it.
-        loadTranslation(QStringLiteral("en"));
-
-        QLocale locale = QLocale::system();
-        if (locale.name() != QStringLiteral("en")) {
-            if (!loadTranslation(locale.name())) {
-                loadTranslation(locale.bcp47Name());
-            }
-        }
+    QTranslator *translator = new QTranslator(QCoreApplication::instance());
+    if (!translator->load(fullPath)) {
+        delete translator;
+        return false;
     }
+    QCoreApplication::instance()->installTranslator(translator);
+    return true;
+}
 
-    // helper to call load() on the correct thread
-    class Loader : public QObject
-    {
-        Q_OBJECT
-
-    public Q_SLOTS:
-        void callLoadAndDeleteSelf()
-        {
-            load();
-            this->deleteLater();
-        }
-    };
+static void load()
+{
+    // The way Qt translation system handles plural forms makes it necessary to
+    // have a translation file which contains only plural forms for `en`. That's
+    // why we load the `en` translation unconditionally, then load the
+    // translation for the current locale to overload it.
+    loadTranslation(QStringLiteral("en"));
 
-    void loadOnMainThread()
-    {
-        // If this library is loaded after the QCoreApplication instance is created
-        // (eg: because it is brought in by a plugin), there is no guarantee this
-        // function will be called on the main thread.
-        // QCoreApplication::installTranslator needs to be called on the main
-        // thread, because it uses QCoreApplication::sendEvent.
-        if (QThread::currentThread() == QCoreApplication::instance()->thread()) {
-            load();
-        } else {
-            // QObjects inherit their parent object's thread
-            Loader *loader = new Loader();
-            loader->moveToThread(QCoreApplication::instance()->thread());
-            QMetaObject::invokeMethod(loader, "callLoadAndDeleteSelf", Qt::AutoConnection);
+    QLocale locale = QLocale::system();
+    if (locale.name() != QStringLiteral("en")) {
+        if (!loadTranslation(locale.name())) {
+            loadTranslation(locale.bcp47Name());
         }
     }
-
 }
 
-Q_COREAPP_STARTUP_FUNCTION(loadOnMainThread)
-
-#include "ECMQmLoader.moc"
+Q_COREAPP_STARTUP_FUNCTION(load)