Merge remote-tracking branch 'origin/5.11' into dev

Change-Id: I9c90d71fde002544fd97df7e8a2690953cf9f817

1 files changed, 51 insertions, 36 deletions

diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index f7da94d111..12390928f0 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -525,21 +525,21 @@ static QWindowGeometrySpecification windowGeometrySpecification = Q_WINDOW_GEOME
         \li \c{-platform} \e {platformName[:options]}, specifies the
             \l{Qt Platform Abstraction} (QPA) plugin.
 
-            Overridden by the \c QT_QPA_PLATFORM environment variable.
+            Overrides the \c QT_QPA_PLATFORM environment variable.
         \li \c{-platformpluginpath} \e path, specifies the path to platform
             plugins.
 
-            Overridden by the \c QT_QPA_PLATFORM_PLUGIN_PATH environment
-            variable.
+            Overrides the \c QT_QPA_PLATFORM_PLUGIN_PATH environment variable.
 
         \li \c{-platformtheme} \e platformTheme, specifies the platform theme.
 
-            Overridden by the \c QT_QPA_PLATFORMTHEME environment variable.
+            Overrides the \c QT_QPA_PLATFORMTHEME environment variable.
 
         \li \c{-plugin} \e plugin, specifies additional plugins to load. The argument
             may appear multiple times.
 
-            Overridden by the \c QT_QPA_GENERIC_PLUGINS environment variable.
+            Concatenated with the plugins in the \c QT_QPA_GENERIC_PLUGINS environment
+            variable.
 
         \li \c{-qmljsdebugger=}, activates the QML/JS debugger with a specified port.
             The value must be of format \c{port:1234}\e{[,block]}, where
@@ -1125,6 +1125,8 @@ QWindow *QGuiApplication::topLevelAt(const QPoint &pos)
         \li \c openwfd
         \li \c qnx
         \li \c windows
+        \li \c wayland is a platform plugin for modern Linux desktops and some
+            embedded systems.
         \li \c xcb is the X11 plugin used on regular desktop Linux platforms.
     \endlist
 
@@ -1138,33 +1140,47 @@ QString QGuiApplication::platformName()
            *QGuiApplicationPrivate::platform_name : QString();
 }
 
-static void init_platform(const QString &pluginArgument, const QString &platformPluginPath, const QString &platformThemeName, int &argc, char **argv)
-{
-    // Split into platform name and arguments
-    QStringList arguments = pluginArgument.split(QLatin1Char(':'));
-    const QString name = arguments.takeFirst().toLower();
-    QString argumentsKey = name;
-    argumentsKey[0] = argumentsKey.at(0).toUpper();
-    arguments.append(QLibraryInfo::platformPluginArguments(argumentsKey));
+Q_LOGGING_CATEGORY(lcQpaPluginLoading, "qt.qpa.plugin");
+
+static void init_platform(const QString &pluginNamesWithArguments, const QString &platformPluginPath, const QString &platformThemeName, int &argc, char **argv)
+{
+    QStringList plugins = pluginNamesWithArguments.split(QLatin1Char(';'));
+    QStringList platformArguments;
+    QStringList availablePlugins = QPlatformIntegrationFactory::keys(platformPluginPath);
+    for (auto pluginArgument : plugins) {
+        // Split into platform name and arguments
+        QStringList arguments = pluginArgument.split(QLatin1Char(':'));
+        const QString name = arguments.takeFirst().toLower();
+        QString argumentsKey = name;
+        argumentsKey[0] = argumentsKey.at(0).toUpper();
+        arguments.append(QLibraryInfo::platformPluginArguments(argumentsKey));
+
+        // Create the platform integration.
+        QGuiApplicationPrivate::platform_integration = QPlatformIntegrationFactory::create(name, arguments, argc, argv, platformPluginPath);
+        if (Q_UNLIKELY(!QGuiApplicationPrivate::platform_integration)) {
+            if (availablePlugins.contains(name)) {
+                qCInfo(lcQpaPluginLoading).nospace().noquote()
+                        << "Could not load the Qt platform plugin \"" << name << "\" in \""
+                        << QDir::toNativeSeparators(platformPluginPath) << "\" even though it was found.";
+            } else {
+                qCWarning(lcQpaPluginLoading).nospace().noquote()
+                        << "Could not find the Qt platform plugin \"" << name << "\" in \""
+                        << QDir::toNativeSeparators(platformPluginPath) << "\"";
+            }
+        } else {
+            QGuiApplicationPrivate::platform_name = new QString(name);
+            platformArguments = arguments;
+            break;
+        }
+    }
 
-   // Create the platform integration.
-    QGuiApplicationPrivate::platform_integration = QPlatformIntegrationFactory::create(name, arguments, argc, argv, platformPluginPath);
     if (Q_UNLIKELY(!QGuiApplicationPrivate::platform_integration)) {
-        QStringList keys = QPlatformIntegrationFactory::keys(platformPluginPath);
+        QString fatalMessage = QStringLiteral("This application failed to start because no Qt platform plugin could be initialized. "
+                                              "Reinstalling the application may fix this problem.\n");
 
-        QString fatalMessage;
-        if (keys.contains(name)) {
-            fatalMessage = QStringLiteral("This application failed to start because it could not load the Qt platform plugin \"%2\"\nin \"%3\", even though it was found. ").arg(name, QDir::toNativeSeparators(platformPluginPath));
-            fatalMessage += QStringLiteral("This is usually due to missing dependencies, which you can verify by setting the env variable QT_DEBUG_PLUGINS to 1.\n\n");
-        } else {
-            fatalMessage = QStringLiteral("This application failed to start because it could not find the Qt platform plugin \"%2\"\nin \"%3\".\n\n").arg(name, QDir::toNativeSeparators(platformPluginPath));
-        }
+        if (!availablePlugins.isEmpty())
+            fatalMessage += QStringLiteral("\nAvailable platform plugins are: %1.\n").arg(availablePlugins.join(QLatin1String(", ")));
 
-        if (!keys.isEmpty()) {
-            fatalMessage += QStringLiteral("Available platform plugins are: %1.\n\n").arg(
-                        keys.join(QLatin1String(", ")));
-        }
-        fatalMessage += QStringLiteral("Reinstalling the application may fix this problem.");
 #if defined(Q_OS_WIN) && !defined(Q_OS_WINRT)
         // Windows: Display message box unless it is a console application
         // or debug build showing an assert box.
@@ -1172,11 +1188,10 @@ static void init_platform(const QString &pluginArgument, const QString &platform
             MessageBox(0, (LPCTSTR)fatalMessage.utf16(), (LPCTSTR)(QCoreApplication::applicationName().utf16()), MB_OK | MB_ICONERROR);
 #endif // Q_OS_WIN && !Q_OS_WINRT
         qFatal("%s", qPrintable(fatalMessage));
+
         return;
     }
 
-    QGuiApplicationPrivate::platform_name = new QString(name);
-
     // Many platforms have created QScreens at this point. Finish initializing
     // QHighDpiScaling to be prepared for early calls to qt_defaultDpi().
     if (QGuiApplication::primaryScreen()) {
@@ -1223,9 +1238,9 @@ static void init_platform(const QString &pluginArgument, const QString &platform
 #ifndef QT_NO_PROPERTIES
     // Set arguments as dynamic properties on the native interface as
     // boolean 'foo' or strings: 'foo=bar'
-    if (!arguments.isEmpty()) {
+    if (!platformArguments.isEmpty()) {
         if (QObject *nativeInterface = QGuiApplicationPrivate::platform_integration->nativeInterface()) {
-            for (const QString &argument : qAsConst(arguments)) {
+            for (const QString &argument : qAsConst(platformArguments)) {
                 const int equalsPos = argument.indexOf(QLatin1Char('='));
                 const QByteArray name =
                     equalsPos != -1 ? argument.left(equalsPos).toUtf8() : argument.toUtf8();
@@ -1289,7 +1304,7 @@ void QGuiApplicationPrivate::createPlatformIntegration()
             argv[j++] = argv[i];
             continue;
         }
-        const bool isXcb = platformName == "xcb";
+        const bool xcbIsDefault = platformName.startsWith("xcb");
         const char *arg = argv[i];
         if (arg[1] == '-') // startsWith("--")
             ++arg;
@@ -1302,13 +1317,13 @@ void QGuiApplicationPrivate::createPlatformIntegration()
         } else if (strcmp(arg, "-platformtheme") == 0) {
             if (++i < argc)
                 platformThemeName = QString::fromLocal8Bit(argv[i]);
-        } else if (strcmp(arg, "-qwindowgeometry") == 0 || (isXcb && strcmp(arg, "-geometry") == 0)) {
+        } else if (strcmp(arg, "-qwindowgeometry") == 0 || (xcbIsDefault && strcmp(arg, "-geometry") == 0)) {
             if (++i < argc)
                 windowGeometrySpecification = QWindowGeometrySpecification::fromArgument(argv[i]);
-        } else if (strcmp(arg, "-qwindowtitle") == 0 || (isXcb && strcmp(arg, "-title") == 0)) {
+        } else if (strcmp(arg, "-qwindowtitle") == 0 || (xcbIsDefault && strcmp(arg, "-title") == 0)) {
             if (++i < argc)
                 firstWindowTitle = QString::fromLocal8Bit(argv[i]);
-        } else if (strcmp(arg, "-qwindowicon") == 0 || (isXcb && strcmp(arg, "-icon") == 0)) {
+        } else if (strcmp(arg, "-qwindowicon") == 0 || (xcbIsDefault && strcmp(arg, "-icon") == 0)) {
             if (++i < argc) {
                 icon = QString::fromLocal8Bit(argv[i]);
             }