Core: Return expected_str<void> from IDocumnet::autoSave()

... and adapt caller.

Change-Id: Ib139069a1a44116d661979e115e1a3daebf9b136
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/coreplugin/editormanager/editormanager.cpp

@@ -2382,9 +2382,8 @@ void EditorManagerPrivate::autoSave()
         if (document->filePath().isEmpty()
                 || !savePath.isWritableDir()) // FIXME: save them to a dedicated directory
             continue;
-        QString errorString;
-        if (!document->autoSave(&errorString, saveName))
-            errors << errorString;
+        if (expected_str<void> res = document->autoSave(saveName); !res)
+            errors << res.error();
     }
     if (!errors.isEmpty())
         QMessageBox::critical(ICore::dialogParent(),

src/plugins/coreplugin/idocument.cpp

@@ -647,15 +647,13 @@ void IDocument::setMimeType(const QString &mimeType)
 /*!
     \internal
 */
-bool IDocument::autoSave(QString *errorString, const FilePath &filePath)
+expected_str<void> IDocument::autoSave(const FilePath &filePath)
 {
-    const expected_str<void> res = save(filePath, true);
-    if (!res) {
-        *errorString = res.error();
-        return false;
-    }
+    if (const expected_str<void> res = save(filePath, true); !res)
+        return res;
+
     d->autoSavePath = filePath;
-    return true;
+    return {};
 }
 
 static const char kRestoredAutoSave[] = "RestoredAutoSave";

src/plugins/coreplugin/idocument.h

@@ -104,7 +104,7 @@ public:
 
     void checkPermissions();
 
-    bool autoSave(QString *errorString, const Utils::FilePath &filePath);
+    Utils::expected_str<void> autoSave(const Utils::FilePath &filePath);
     void setRestoredFrom(const Utils::FilePath &path);
     void removeAutoSaveFile();