LanguageClient: Do not add hover handler twice to editor

Check whether an editor already contains the hover handler before adding
to the list of handlers. Also remove the handler when a document is
deactivated for a specific client.

Change-Id: Iec1d3a0fd1dc3f02c8dd50b8968ff063efe2508a
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/languageclient/client.cpp

@@ -377,7 +377,7 @@ void Client::activateDocument(TextEditor::TextDocument *document)
     for (Core::IEditor *editor : Core::DocumentModel::editorsForDocument(document)) {
         updateEditorToolBar(editor);
         if (auto textEditor = qobject_cast<TextEditor::BaseTextEditor *>(editor))
-            textEditor->editorWidget()->addHoverHandler(hoverHandler());
+            textEditor->editorWidget()->addHoverHandler(&m_hoverHandler);
     }
 }
 
@@ -387,6 +387,10 @@ void Client::deactivateDocument(TextEditor::TextDocument *document)
     resetAssistProviders(document);
     if (TextEditor::SyntaxHighlighter *highlighter = document->syntaxHighlighter())
         highlighter->clearAllExtraFormats();
+    for (Core::IEditor *editor : Core::DocumentModel::editorsForDocument(document)) {
+        if (auto textEditor = qobject_cast<TextEditor::BaseTextEditor *>(editor))
+            textEditor->editorWidget()->removeHoverHandler(&m_hoverHandler);
+    }
 }
 
 bool Client::documentOpen(TextEditor::TextDocument *document) const

src/plugins/texteditor/texteditor.cpp

@@ -5640,6 +5640,7 @@ void TextEditorWidget::showDefaultContextMenu(QContextMenuEvent *e, Id menuConte
 
 void TextEditorWidget::addHoverHandler(BaseHoverHandler *handler)
 {
+    if (!d->m_hoverHandlers.contains(handler))
         d->m_hoverHandlers.append(handler);
 }