Add QXmppError holding a description and std::any

1 files changed, 51 insertions, 0 deletions

diff --git a/src/base/QXmppError.h b/src/base/QXmppError.h
new file mode 100644
index 00000000..a646b6e5
--- /dev/null
+++ b/src/base/QXmppError.h
@@ -0,0 +1,51 @@
+// SPDX-FileCopyrightText: 2022 Linus Jahn <lnj@kaidan.im>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+#ifndef QXMPPERROR_H
+#define QXMPPERROR_H
+
+#include "QXmppGlobal.h"
+
+#include <any>
+#include <optional>
+
+struct QXMPP_EXPORT QXmppError
+{
+    QString description;
+    std::any error;
+
+    bool isFileError() const;
+    bool isNetworkError() const;
+    bool isStanzaError() const;
+
+    template<typename T>
+    bool holdsType() const
+    {
+        return error.type().hash_code() == typeid(T).hash_code();
+    }
+    template<typename T>
+    std::optional<T> value() const
+    {
+        // any_cast always checks this, to avoid an additional check we use exceptions
+        try {
+            return std::any_cast<T>(error);
+        } catch (std::bad_any_cast) {
+            return {};
+        }
+    }
+    template<typename T>
+    std::optional<T> takeValue()
+    {
+        // we can't use unchecked any_cast with moving because we can't access the error after a
+        // failed any_cast
+        if (error.type().hash_code() == typeid(T).hash_code()) {
+            auto value = std::any_cast<T>(std::move(error));
+            error = std::any();
+            return value;
+        }
+        return {};
+    }
+};
+
+#endif  // QXMPPERROR_H