Add implementation of QCocoaInputContext::commit()

Without this we end up treating input method commits from the
input items as cancellations, as the base class implementation
doesn't do anything.

Pick-to: 6.2
Change-Id: Ieeed71404ee32ab51287b2f4f2d70ffcf9d8e7ef
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

src/plugins/platforms/cocoa/qcocoainputcontext.h

@@ -59,6 +59,7 @@ public:
 
     void setFocusObject(QObject *object) override;
 
+    void commit() override;
     void reset() override;
 
     QLocale locale() const override { return m_locale; }

src/plugins/platforms/cocoa/qcocoainputcontext.mm

@@ -95,6 +95,33 @@ QCocoaInputContext::~QCocoaInputContext()
 {
 }
 
+/*!
+    Commits the current composition if there is one,
+    by "unmarking" the text in the edit buffer, and
+    informing the system input context of this fact.
+*/
+void QCocoaInputContext::commit()
+{
+    qCDebug(lcQpaInputMethods) << "Committing composition";
+
+    if (!m_focusWindow)
+        return;
+
+    auto *platformWindow = m_focusWindow->handle();
+    if (!platformWindow)
+        return;
+
+    auto *cocoaWindow = static_cast<QCocoaWindow *>(platformWindow);
+    QNSView *view = qnsview_cast(cocoaWindow->view());
+    if (!view)
+        return;
+
+    QMacAutoReleasePool pool;
+    [view unmarkText];
+    [view.inputContext discardMarkedText];
+}
+
+
 /*!
     \brief Cancels a composition.
 */