Add QT_IM_MODULES env to allows specify multi IM key

Like as QT_QPA_PLATFORM, supports specifying multiple keys, and can
perform fallback operations to prioritize the use of a certain plug-in.
This is useful when using Wayland and XWayland applications at the same
time. For an example, we can set "QT_IM_MODULES=wayland;fcitx", and the
wayland application will use the wayland input context plugin, the
xwayland application will use fcitx, which can't be done without adding
a new environment variable, if we specify "QT_IM_MODULE=wayland", the
XWayland applications may not be able to use the input method.

Fixes: QTBUG-120202
Change-Id: Iac408af241963147747a2fe685f1e27bf9d9ee64
Reviewed-by: Liang Qi <liang.qi@qt.io>
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
Reviewed-by: David Edmundson <davidedmundson@kde.org>

1 files changed, 6 insertions, 5 deletions

diff --git a/src/plugins/platforms/xcb/qxcbintegration.cpp b/src/plugins/platforms/xcb/qxcbintegration.cpp
index e76a34fce8..4dafae31e3 100644
--- a/src/plugins/platforms/xcb/qxcbintegration.cpp
+++ b/src/plugins/platforms/xcb/qxcbintegration.cpp
@@ -344,11 +344,12 @@ void QXcbIntegration::initialize()
     const auto defaultInputContext = "compose"_L1;
     // Perform everything that may potentially need the event dispatcher (timers, socket
     // notifiers) here instead of the constructor.
-    QString icStr = QPlatformInputContextFactory::requested();
-    if (icStr.isNull())
-        icStr = defaultInputContext;
-    m_inputContext.reset(QPlatformInputContextFactory::create(icStr));
-    if (!m_inputContext && icStr != defaultInputContext && icStr != "none"_L1)
+    auto icStrs = QPlatformInputContextFactory::requested();
+    if (icStrs.isEmpty())
+        icStrs = { defaultInputContext };
+    m_inputContext.reset(QPlatformInputContextFactory::create(icStrs));
+    if (!m_inputContext && !icStrs.contains(defaultInputContext)
+        && icStrs != QStringList{"none"_L1})
         m_inputContext.reset(QPlatformInputContextFactory::create(defaultInputContext));
 
     connection()->keyboard()->initialize();