Harmonize input context selection

Input context selection works differently across platforms. On some
platforms it is not possible to request a specific context at all
(e.g. Wayland). This will be unified, depending on the environment
variable "QT_IM_MODULE", you will get:
- null:  default (platform) context, if defined (otherwise no context)
- empty: no context
- set:   set one, if it exists and is valid (otherwise no context)

[ChangeLog][Platform Specific Changes] Haromnized input context selection.
QT_IM_MODULE environment variable will be taken into account.

Change-Id: Ic8f826fbc6ace25941cd19b9b086943e848fbe01
Reviewed-by: Lars Knoll <lars.knoll@theqtcompany.com>
Reviewed-by: Nedim Hadzic <nedim.hadzic@pelagicore.com>

4 files changed, 11 insertions, 11 deletions

diff --git a/src/plugins/platforms/cocoa/qcocoaintegration.mm b/src/plugins/platforms/cocoa/qcocoaintegration.mm
index 2e6bfc95db..051a1c8710 100644
--- a/src/plugins/platforms/cocoa/qcocoaintegration.mm
+++ b/src/plugins/platforms/cocoa/qcocoaintegration.mm
@@ -47,6 +47,7 @@
 #include "qcocoamimetypes.h"
 #include "qcocoaaccessibility.h"
 
+#include <qpa/qplatforminputcontextfactory_p.h>
 #include <qpa/qplatformaccessibility.h>
 #include <qpa/qplatforminputcontextfactory_p.h>
 #include <QtCore/qcoreapplication.h>
@@ -286,9 +287,9 @@ QCocoaIntegration::QCocoaIntegration(const QStringList &paramList)
         qWarning("Creating multiple Cocoa platform integrations is not supported");
     mInstance = this;
 
-    mInputContext.reset(QPlatformInputContextFactory::create());
-    if (mInputContext.isNull())
-        mInputContext.reset(new QCocoaInputContext());
+    QString icStr = QPlatformInputContextFactory::requested();
+    icStr.isNull() ? mInputContext.reset(new QCocoaInputContext)
+                   : mInputContext.reset(QPlatformInputContextFactory::create(icStr));
 
     initResources();
     QMacAutoReleasePool pool;
diff --git a/src/plugins/platforms/windows/qwindowsintegration.cpp b/src/plugins/platforms/windows/qwindowsintegration.cpp
index f97c23c207..bbb1f68a52 100644
--- a/src/plugins/platforms/windows/qwindowsintegration.cpp
+++ b/src/plugins/platforms/windows/qwindowsintegration.cpp
@@ -264,10 +264,9 @@ QWindowsIntegration::~QWindowsIntegration()
 
 void QWindowsIntegration::initialize()
 {
-    if (QPlatformInputContext *pluginContext = QPlatformInputContextFactory::create())
-        d->m_inputContext.reset(pluginContext);
-    else
-        d->m_inputContext.reset(new QWindowsInputContext);
+    QString icStr = QPlatformInputContextFactory::requested();
+    icStr.isNull() ? d->m_inputContext.reset(new QWindowsInputContext)
+                   : d->m_inputContext.reset(QPlatformInputContextFactory::create(icStr));
 }
 
 bool QWindowsIntegration::hasCapability(QPlatformIntegration::Capability cap) const
diff --git a/src/plugins/platforms/xcb/qxcbconnection.cpp b/src/plugins/platforms/xcb/qxcbconnection.cpp
index 15d3575e60..e612cff9a3 100644
--- a/src/plugins/platforms/xcb/qxcbconnection.cpp
+++ b/src/plugins/platforms/xcb/qxcbconnection.cpp
@@ -590,9 +590,6 @@ QXcbConnection::QXcbConnection(QXcbNativeInterface *nativeInterface, bool canGra
         qCDebug(QT_XCB_GLINTEGRATION) << "Failed to create xcb gl-integration";
 
     sync();
-
-    if (qEnvironmentVariableIsEmpty("QT_IM_MODULE"))
-        qputenv("QT_IM_MODULE", QByteArray("compose"));
 }
 
 QXcbConnection::~QXcbConnection()
diff --git a/src/plugins/platforms/xcb/qxcbintegration.cpp b/src/plugins/platforms/xcb/qxcbintegration.cpp
index fc06f1a7b0..9cedfa77ad 100644
--- a/src/plugins/platforms/xcb/qxcbintegration.cpp
+++ b/src/plugins/platforms/xcb/qxcbintegration.cpp
@@ -268,7 +268,10 @@ void QXcbIntegration::initialize()
 {
     // Perform everything that may potentially need the event dispatcher (timers, socket
     // notifiers) here instead of the constructor.
-    m_inputContext.reset(QPlatformInputContextFactory::create());
+    QString icStr = QPlatformInputContextFactory::requested();
+    if (icStr.isNull())
+        icStr = QLatin1String("compose");
+    m_inputContext.reset(QPlatformInputContextFactory::create(icStr));
 }
 
 void QXcbIntegration::moveToScreen(QWindow *window, int screen)