Make sure we load translations on the main thread.

Because the old implementation (accidentally) worked when you put the
ecm_create_qm_loader call in a different CMakeLists.txt file to the
target the file was added to, some projects did this.

This won't work with build-time-generated files, though, like moc files.
So we (ab)use QTimer events to make the loading happen on the main
thread.

BUG: 346188
REVIEW: 126000

5 files changed, 128 insertions, 2 deletions

diff --git a/tests/ECMPoQmToolsTest/CMakeLists.txt b/tests/ECMPoQmToolsTest/CMakeLists.txt
index 73d2b427..2cd76f8f 100644
--- a/tests/ECMPoQmToolsTest/CMakeLists.txt
+++ b/tests/ECMPoQmToolsTest/CMakeLists.txt
@@ -82,7 +82,7 @@ target_link_libraries(tr_test PRIVATE Qt5::Core)
 
 
 #
-# single-threaded test (different catalog name)
+# single-threaded test (different catalog name, automoc)
 #
 # This is to check we don't overwrite previously-generated files.
 set(tr_test_2_SRCS
@@ -90,15 +90,55 @@ set(tr_test_2_SRCS
 )
 ecm_create_qm_loader(tr_test_2_SRCS catalog2)
 add_executable(tr_test_2 ${tr_test_2_SRCS})
+set_target_properties(tr_test_2 PROPERTIES AUTOMOC ON)
+target_include_directories(tr_test_2 PRIVATE "${CMAKE_CURRENT_BINARY_DIR}")
 target_link_libraries(tr_test_2 PRIVATE Qt5::Core)
 
 
 #
+# module for tr_thread_test
+#
+add_library(tr_thread_module MODULE tr_thread_test_module.cpp ${QMLOADER_FILES})
+target_link_libraries(tr_thread_module PRIVATE Qt5::Core)
+
+
+#
+# loading a module on a thread other than the main thread
+# (automoc)
+#
+set(tr_thread_test_SRCS
+    tr_thread_test.cpp
+)
+ecm_create_qm_loader(tr_thread_test_SRCS catalog)
+add_executable(tr_thread_test ${tr_thread_test_SRCS})
+set_target_properties(tr_thread_test PROPERTIES AUTOMOC ON)
+target_include_directories(tr_thread_test PRIVATE "${CMAKE_CURRENT_BINARY_DIR}")
+target_compile_definitions(tr_thread_test PRIVATE "MODULE_PATH=\"$<TARGET_FILE:tr_thread_module>\"")
+target_link_libraries(tr_thread_test PRIVATE Qt5::Core)
+
+
+#
+# loading a module on a thread other than the main thread
+# (different catalog, no AUTOMOC)
+#
+qt5_generate_moc(tr_thread_test.cpp "${CMAKE_CURRENT_BINARY_DIR}/tr_thread_test.moc")
+set(tr_thread_test_2_SRCS
+    tr_thread_test.cpp
+    "${CMAKE_CURRENT_BINARY_DIR}/tr_thread_test.moc"
+)
+ecm_create_qm_loader(tr_thread_test_2_SRCS catalog2)
+add_executable(tr_thread_test_2 ${tr_thread_test_2_SRCS})
+target_include_directories(tr_thread_test_2 PRIVATE "${CMAKE_CURRENT_BINARY_DIR}")
+target_compile_definitions(tr_thread_test_2 PRIVATE "MODULE_PATH=\"$<TARGET_FILE:tr_thread_module>\"")
+target_link_libraries(tr_thread_test_2 PRIVATE Qt5::Core)
+
+
+#
 # call to ecm_create_qm_loader is in a different CMakeLists.txt to where
 # the target it is added to is defined
 #
 # This is not something we want people to do, but it's unfortunately something
-# projects have done and we need to keep them building
+# projects have done and we need to keep them building.
 unset(QMLOADER_FILES)
 ecm_create_qm_loader(QMLOADER_FILES catalog)
 assert_var_defined(QMLOADER_FILES)
diff --git a/tests/ECMPoQmToolsTest/check.cmake.in b/tests/ECMPoQmToolsTest/check.cmake.in
index 5329b78d..4fe2ac33 100644
--- a/tests/ECMPoQmToolsTest/check.cmake.in
+++ b/tests/ECMPoQmToolsTest/check.cmake.in
@@ -87,6 +87,9 @@ if("@CMAKE_SYSTEM_NAME@" STREQUAL "Linux")
     check_translations(TR_TEST_2 "${TR_TEST_2_EXEC}" catalog2)
 
     check_translations(TR_TEST_SUBDIR "${TR_TEST_SUBDIR_EXEC}" catalog)
+
+    check_translations(TR_THREAD_TEST "${TR_THREAD_TEST_EXEC}" catalog)
+    check_translations(TR_THREAD_TEST_2 "${TR_THREAD_TEST_2_EXEC}" catalog2)
 endif()
 
 if (fail)
diff --git a/tests/ECMPoQmToolsTest/check_conf.cmake.in b/tests/ECMPoQmToolsTest/check_conf.cmake.in
index 7bd11c36..a752d5bd 100644
--- a/tests/ECMPoQmToolsTest/check_conf.cmake.in
+++ b/tests/ECMPoQmToolsTest/check_conf.cmake.in
@@ -1,3 +1,5 @@
 set(TR_TEST_EXEC "$<TARGET_FILE:tr_test>")
 set(TR_TEST_2_EXEC "$<TARGET_FILE:tr_test_2>")
 set(TR_TEST_SUBDIR_EXEC "$<TARGET_FILE:tr_test_subdir>")
+set(TR_THREAD_TEST_EXEC "$<TARGET_FILE:tr_thread_test>")
+set(TR_THREAD_TEST_2_EXEC "$<TARGET_FILE:tr_thread_test_2>")
diff --git a/tests/ECMPoQmToolsTest/tr_thread_test.cpp b/tests/ECMPoQmToolsTest/tr_thread_test.cpp
new file mode 100644
index 00000000..40e4d1eb
--- /dev/null
+++ b/tests/ECMPoQmToolsTest/tr_thread_test.cpp
@@ -0,0 +1,69 @@
+#include <QCoreApplication>
+#include <QLibrary>
+#include <QMetaObject>
+#include <QThread>
+
+class Thread : public QThread
+{
+    Q_OBJECT
+
+    QLibrary *m_lib;
+
+public:
+    Thread()
+        : m_lib(0)
+    {}
+    ~Thread()
+    {
+        delete m_lib;
+    }
+
+Q_SIGNALS:
+    void libraryLoaded();
+
+public Q_SLOTS:
+    void printStrings()
+    {
+        Q_ASSERT(QThread::currentThread() == QCoreApplication::instance()->thread());
+
+        QFunctionPointer print_strings = m_lib->resolve("print_strings");
+        if (print_strings) {
+            print_strings();
+        } else {
+            qFatal("Could not resolve print_strings: %s", qPrintable(m_lib->errorString()));
+        }
+
+        QCoreApplication::instance()->quit();
+    }
+protected:
+    void run()
+    {
+        m_lib = new QLibrary(MODULE_PATH);
+
+        if (!m_lib->load()) {
+            qFatal("Could not load module: %s", m_lib->errorString().toUtf8().data());
+        }
+
+        // Queue a call to printStrings() on the main event loop (giving the
+        // translations a chance to be loaded).
+        QMetaObject::invokeMethod(this, "printStrings", Qt::QueuedConnection);
+    }
+};
+
+int main(int argc, char** argv)
+{
+    QCoreApplication app(argc, argv);
+
+    Thread thread;
+
+    // Start the thread *after* QCoreApplication is started (otherwise the
+    // plugin's startup function won't be run on the Thread, and we won't test
+    // what we wanted to test).
+    QMetaObject::invokeMethod(&thread, "start", Qt::QueuedConnection);
+
+    app.exec();
+
+    return 0;
+}
+
+#include "tr_thread_test.moc"
diff --git a/tests/ECMPoQmToolsTest/tr_thread_test_module.cpp b/tests/ECMPoQmToolsTest/tr_thread_test_module.cpp
new file mode 100644
index 00000000..b9000ffa
--- /dev/null
+++ b/tests/ECMPoQmToolsTest/tr_thread_test_module.cpp
@@ -0,0 +1,12 @@
+#include <QCoreApplication>
+#include <QTextStream>
+
+#include <stdio.h>
+
+extern "C" Q_DECL_EXPORT void print_strings()
+{
+    QTextStream output(stdout);
+
+    output << QCoreApplication::translate("testcontext", "test string") << ":";
+    output << QCoreApplication::translate("testcontext", "test plural %n", 0, 5) << '\n';
+}