3 files changed, 97 insertions, 0 deletions
diff --git a/lib/olm/errors.h b/lib/olm/errors.h
new file mode 100644
index 00000000..e51400ef
--- /dev/null
+++ b/lib/olm/errors.h
@@ -0,0 +1,46 @@
+// SPDX-FileCopyrightText: 2021 Carl Schwan <carlschwan@kde.org>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+#pragma once
+
+//! All errors that could be caused by an operation regarding an `QOlmAccount`.
+//! Errors are named exactly like the ones in libolm.
+enum OlmAccountError {
+    BadAccountKey,
+    BadMessageKeyId,
+    InvalidBase64,
+    NotEnoughRandom,
+    OutputBufferTooSmall,
+    Unknown,
+};
+
+//! All errors that could be caused by an operation regarding an `QOlmSession`.
+//! Errors are named exactly like the ones in libolm.
+enum OlmSessionError {
+    BadAccountKey,
+    BadMessageFormat,
+    BadMessageKeyId,
+    BadMessageMac,
+    BadMessageVersion,
+    InvalidBase64,
+    NotEnoughRandom,
+    OutputBufferTooSmall,
+    Unknown,
+};
+
+//! All errors that could be caused by an operation
+//! regarding QOlmOutboundGroupSession and QOlmInboundGroupSession.
+//! Errors are named exactly like the ones in libolm.
+enum OlmGroupSessionError {
+    BadAccountKey,
+    BadMessageFormat,
+    BadMessageMac,
+    BadMessageVersion,
+    BadSessionKey,
+    InvalidBase64,
+    NotEnoughRandom,
+    OutputBufferTooSmall,
+    UnknownMessageIndex,
+    Unknown,
+};
diff --git a/lib/olm/qolminboundsession.cpp b/lib/olm/qolminboundsession.cpp
new file mode 100644
index 00000000..fbcaa802
--- /dev/null
+++ b/lib/olm/qolminboundsession.cpp
@@ -0,0 +1,30 @@
+// SPDX-FileCopyrightText: 2021 Carl Schwan <carlschwan@kde.org>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+#include <qolminboundsession.h>
+
+std::variant<QOlmInboundGroupSession, OlmInboundGroupSession> QOlmInboundGroupSession::create(const QString &key)
+{
+    auto olmInboundGroupSessionBuf = QByteArray(olm_inbound_group_session_size(), '0');
+
+    const auto olmInboundGroupSession = olm_inbound_group_session(olmInboundGroupSessionBuf.data());
+
+    QByteArray keyBuf = key.toUtf8();
+
+    const auto error = olm_init_inbound_group_session(olmInboundGroupSession, keyBuf.data(), keyBuf.size());
+
+    if (error == olm_error()) {
+        return 
+    }
+
+    if create_error == errors::olm_error() {
+        Err(Self::last_error(olm_inbound_group_session_ptr))
+    } else {
+        Ok(OlmInboundGroupSession {
+            group_session_ptr: olm_inbound_group_session_ptr,
+            group_session_buf: olm_inbound_group_session_buf,
+        })
+    }
+
+}
diff --git a/lib/olm/qolminboundsession.h b/lib/olm/qolminboundsession.h
new file mode 100644
index 00000000..520f8b68
--- /dev/null
+++ b/lib/olm/qolminboundsession.h
@@ -0,0 +1,21 @@
+// SPDX-FileCopyrightText: 2021 Carl Schwan <carlschwan@kde.org>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+#pragma once
+
+#include <QByteArray>
+#include <variant>
+
+//! An in-bound group session is responsible for decrypting incoming
+//! communication in a Megolm session.
+struct QOlmInboundGroupSession
+{
+public:
+    //! Creates a new instance of `OlmInboundGroupSession`.
+    static std::variant<OlmInboundGroupSession, OlmGroupSessionError> create(const QString &key);
+private:
+    OlmInboundGroupSession *m_groupSession
+    QByteArray m_buffer;
+};
+