Implement XEP-0384: OMEMO Encryption v0.8

This implements XEP-0384 in version v0.8 with a manager and storage
classes to be user-implemented for persistant storage.

The license of the code is LGPL-2.1-or-later as usual.  However since
libomemo-c (libsignal-protocol-c) is GPL-3.0, the built binary is always
licensed under GPL-3.0.  Having our code LGPL licensed will make it
avoids relicensing in the future in case we port it to an LGPL
compatible omemo library.

Closes #133.

Co-authored-by: Linus Jahn <lnj@kaidan.im>

1 files changed, 97 insertions, 0 deletions

diff --git a/src/client/QXmppOmemoStorage.cpp b/src/client/QXmppOmemoStorage.cpp
new file mode 100644
index 00000000..97b66dbe
--- /dev/null
+++ b/src/client/QXmppOmemoStorage.cpp
@@ -0,0 +1,97 @@
+// SPDX-FileCopyrightText: 2022 Melvin Keskin <melvo@olomono.de>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+///
+/// \class QXmppOmemoStorage
+///
+/// \brief The QXmppOmemoStorage class stores data used by
+/// \xep{0384, OMEMO Encryption}.
+///
+/// \warning THIS API IS NOT FINALIZED YET!
+///
+/// \since QXmpp 1.5
+///
+
+///
+/// \fn QXmppOmemoStorage::allData()
+///
+/// Returns all data used by OMEMO.
+///
+/// \return the OMEMO data
+///
+
+///
+/// \fn QXmppOmemoStorage::setOwnDevice(const std::optional<OwnDevice> &device)
+///
+/// Sets the own device (i.e., the device used by this client instance).
+///
+/// \param device own device
+///
+
+///
+/// \fn QXmppOmemoStorage::addSignedPreKeyPair(uint32_t keyId, const SignedPreKeyPair &keyPair)
+///
+/// Adds a signed pre key pair.
+///
+/// \param keyId ID of the signed pre key pair
+/// \param keyPair signed pre key pair
+///
+
+///
+/// \fn QXmppOmemoStorage::removeSignedPreKeyPair(uint32_t keyId)
+///
+/// Removes a signed pre key pair.
+///
+/// \param keyId ID of the signed pre key pair
+///
+
+///
+/// \fn QXmppOmemoStorage::addPreKeyPairs(const QHash<uint32_t, QByteArray> &keyPairs)
+///
+/// Adds pre key pairs.
+///
+/// \param keyPairs key IDs mapped to the pre key pairs
+///
+
+///
+/// \fn QXmppOmemoStorage::removePreKeyPair(uint32_t keyId)
+///
+/// Removes a pre key pair.
+///
+/// \param keyId ID of the pre key pair
+///
+
+///
+/// \fn QXmppOmemoStorage::addDevice(const QString &jid, uint32_t deviceId, const Device &device)
+///
+/// Adds other devices (i.e., all devices but the own one).
+///
+/// \param jid JID of the device owner
+/// \param deviceId ID of the device
+/// \param device device being added
+///
+
+///
+/// \fn QXmppOmemoStorage::removeDevice(const QString &jid, uint32_t deviceId)
+///
+/// Removes a device of the other devices (i.e., all devices but the own one).
+///
+/// \param jid JID of the device owner
+/// \param deviceId ID of the device being removed
+///
+
+///
+/// \fn QXmppOmemoStorage::removeDevices(const QString &jid)
+///
+/// Removes all devices of a passed JID from the other devices (i.e., all
+/// devices but the own one).
+///
+/// \param jid JID of the device owner
+///
+
+///
+/// \fn QXmppOmemoStorage::resetAll()
+///
+/// Resets all data.
+///