fix(dock): fix pasting text in Wayland plugin windows

To fix pasting text in Wayland plugin windows, this commit ensures that nested
Wayland clients can correctly receive host clipboard contents.

Wayland compositor (dde-shell) does not automatically synchronize the host system's
clipboard to its nested clients. This caused plugin popup windows to be unable to
paste text that was copied from outside applications.

This fix enables retained selection in QWaylandCompositor and explicitly listens to
QClipboard::changed from the host environment to forward the QMimeData to the
compositor via overrideSelection().

Log: fix pasting text in Wayland plugin windows
Pms: BUG-329435

Author: yixinshark

panels/dock/pluginmanagerextension.cpp

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2023 UnionTech Software Technology Co., Ltd.
+// SPDX-FileCopyrightText: 2023 - 2026 UnionTech Software Technology Co., Ltd.
 //
 // SPDX-License-Identifier: GPL-3.0-or-later
 
@@ -26,6 +26,11 @@
 #include <QtWaylandCompositor/QWaylandQtTextInputMethod>
 #include <QtWaylandCompositor/QWaylandQuickItem>
 
+#include <QGuiApplication>
+#include <QInputMethod>
+#include <QClipboard>
+#include <QMimeData>
+
 #include <QJsonObject>
 #include <QJsonParseError>
 
@@ -39,9 +44,6 @@
 #include <private/qwlqttouch_p.h>
 #endif
 
-#include <QtGui/qguiapplication.h>
-#include <QtGui/qinputmethod.h>
-
 DGUI_USE_NAMESPACE
 
 struct WlQtTextInputMethodHelper : public QtWaylandServer::qt_text_input_method_v1 {
@@ -75,11 +77,9 @@ struct WlQtTextInputMethodHelper : public QtWaylandServer::qt_text_input_method_
             d->cursorRectangle = QRect();
             d->preferredLanguage.clear();
             d->hints = Qt::InputMethodHints();
-            auto *helper = static_cast<WlQtTextInputMethodHelper*>(base);
-            helper->send_enter(d->resource->handle, d->focusedSurface->resource());
-            
-            helper->send_input_direction_changed(d->resource->handle, int(qApp->inputMethod()->inputDirection()));
-            helper->send_locale_changed(d->resource->handle, qApp->inputMethod()->locale().bcp47Name());
+            base->send_enter(d->resource->handle, d->focusedSurface->resource());
+            base->send_input_direction_changed(d->resource->handle, int(qApp->inputMethod()->inputDirection()));
+            base->send_locale_changed(d->resource->handle, qApp->inputMethod()->locale().bcp47Name());
 
             d->focusDestroyListener.listenForDestruction(surface->resource());
             if (d->inputPanelVisible && d->enabledSurfaces.values().contains(surface))
@@ -516,6 +516,21 @@ void PluginManager::initialize()
 
     // 设置 text input 焦点代理
     setupTextInputProxy(compositor);
+
+    // 启用剪贴板保留并在宿主系统剪贴板更新时同步给插件 Wayland 客户端，实现粘贴功能
+    compositor->setRetainedSelectionEnabled(true);
+    if (auto *clipboard = QGuiApplication::clipboard()) {
+        QObject::connect(clipboard, &QClipboard::changed, this, [compositor](QClipboard::Mode mode) {
+            if (mode == QClipboard::Clipboard) {
+                if (const QMimeData *mimeData = QGuiApplication::clipboard()->mimeData(mode)) {
+                    compositor->overrideSelection(mimeData);
+                }
+            }
+        });
+        if (const QMimeData *mimeData = clipboard->mimeData(QClipboard::Clipboard)) {
+            compositor->overrideSelection(mimeData);
+        }
+    }
 }
 
 void PluginManager::updateDockOverflowState(int state)
@@ -836,6 +851,10 @@ void PluginManager::setupTextInputProxy(QWaylandCompositor *compositor)
         (QWaylandSurface *newFocus, QWaylandSurface *oldFocus) {
         Q_UNUSED(oldFocus);
 
+        if (newFocus) {
+            newFocus->updateSelection();
+        }
+
         // 由于 Deepin Qt6 构建中 QWaylandTextInput/V3 的公开类符号没有导出，
         // 无法使用 findIn() 和公开的 setFocus()。
         // 改用 Private API：遍历 seat 的 extension 列表，

panels/dock/pluginmanagerextension_p.h

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2023 UnionTech Software Technology Co., Ltd.
+// SPDX-FileCopyrightText: 2023 - 2026 UnionTech Software Technology Co., Ltd.
 //
 // SPDX-License-Identifier: GPL-3.0-or-later