1 files changed, 91 insertions, 0 deletions
diff --git a/lib/e2ee/qolmsession.h b/lib/e2ee/qolmsession.h
new file mode 100644
index 00000000..f20c9837
--- /dev/null
+++ b/lib/e2ee/qolmsession.h
@@ -0,0 +1,91 @@
+// SPDX-FileCopyrightText: 2021 Alexey Andreyev <aa13q@ya.ru>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+#pragma once
+
+#include <QDebug>
+#include <olm/olm.h> // FIXME: OlmSession
+#include "e2ee/e2ee.h"
+#include "e2ee/qolmmessage.h"
+#include "e2ee/qolmerrors.h"
+#include "e2ee/qolmaccount.h"
+
+namespace Quotient {
+
+class QOlmAccount;
+class QOlmSession;
+
+//! Either an outbound or inbound session for secure communication.
+class QUOTIENT_API QOlmSession
+{
+public:
+    ~QOlmSession();
+    //! Creates an inbound session for sending/receiving messages from a received 'prekey' message.
+    static std::variant<std::unique_ptr<QOlmSession>, QOlmError>
+    createInboundSession(QOlmAccount* account, const QOlmMessage& preKeyMessage);
+
+    static std::variant<std::unique_ptr<QOlmSession>, QOlmError>
+    createInboundSessionFrom(QOlmAccount* account,
+                             const QString& theirIdentityKey,
+                             const QOlmMessage& preKeyMessage);
+
+    static std::variant<std::unique_ptr<QOlmSession>, QOlmError>
+    createOutboundSession(QOlmAccount* account, const QString& theirIdentityKey,
+                          const QString& theirOneTimeKey);
+
+    //! Serialises an `QOlmSession` to encrypted Base64.
+    std::variant<QByteArray, QOlmError> pickle(const PicklingMode &mode);
+
+    //! Deserialises from encrypted Base64 that was previously obtained by pickling a `QOlmSession`.
+    static std::variant<std::unique_ptr<QOlmSession>, QOlmError> unpickle(
+        const QByteArray& pickled, const PicklingMode& mode);
+
+    //! Encrypts a plaintext message using the session.
+    QOlmMessage encrypt(const QString &plaintext);
+
+    //! Decrypts a message using this session. Decoding is lossy, meaing if
+    //! the decrypted plaintext contains invalid UTF-8 symbols, they will
+    //! be returned as `U+FFFD` (�).
+    std::variant<QString, QOlmError> decrypt(const QOlmMessage &message) const;
+
+    //! Get a base64-encoded identifier for this session.
+    QByteArray sessionId() const;
+
+    //! The type of the next message that will be returned from encryption.
+    QOlmMessage::Type encryptMessageType();
+
+    //! Checker for any received messages for this session.
+    bool hasReceivedMessage() const;
+
+    //! Checks if the 'prekey' message is for this in-bound session.
+    std::variant<bool, QOlmError> matchesInboundSession(
+        const QOlmMessage& preKeyMessage) const;
+
+    //! Checks if the 'prekey' message is for this in-bound session.
+    std::variant<bool, QOlmError> matchesInboundSessionFrom(
+        const QString& theirIdentityKey, const QOlmMessage& preKeyMessage) const;
+
+    friend bool operator<(const QOlmSession& lhs, const QOlmSession& rhs)
+    {
+        return lhs.sessionId() < rhs.sessionId();
+    }
+
+    friend bool operator<(const std::unique_ptr<QOlmSession>& lhs,
+                          const std::unique_ptr<QOlmSession>& rhs)
+    {
+        return *lhs < *rhs;
+    }
+
+    OlmSession* raw() const { return m_session; }
+
+    QOlmSession(OlmSession* session);
+private:
+    //! Helper function for creating new sessions and handling errors.
+    static OlmSession* create();
+    static std::variant<std::unique_ptr<QOlmSession>, QOlmError> createInbound(
+        QOlmAccount* account, const QOlmMessage& preKeyMessage,
+        bool from = false, const QString& theirIdentityKey = "");
+    OlmSession* m_session;
+};
+} //namespace Quotient