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, 119 insertions, 0 deletions

diff --git a/src/client/QXmppOmemoMemoryStorage.cpp b/src/client/QXmppOmemoMemoryStorage.cpp
new file mode 100644
index 00000000..6ff81002
--- /dev/null
+++ b/src/client/QXmppOmemoMemoryStorage.cpp
@@ -0,0 +1,119 @@
+// SPDX-FileCopyrightText: 2022 Melvin Keskin <melvo@olomono.de>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+#include "QXmppOmemoMemoryStorage.h"
+
+#include "QXmppFutureUtils_p.h"
+
+using namespace QXmpp::Private;
+
+///
+/// \class QXmppOmemoMemoryStorage
+///
+/// \brief The QXmppOmemoMemoryStorage class stores data used by
+/// \xep{0384, OMEMO Encryption} in the memory.
+///
+/// \warning THIS API IS NOT FINALIZED YET!
+///
+/// \since QXmpp 1.5
+///
+
+class QXmppOmemoMemoryStoragePrivate
+{
+public:
+    bool isSetUp = false;
+
+    std::optional<QXmppOmemoStorage::OwnDevice> ownDevice;
+
+    // IDs of pre key pairs mapped to pre key pairs
+    QHash<uint32_t, QByteArray> preKeyPairs;
+
+    // IDs of signed pre key pairs mapped to signed pre key pairs
+    QHash<uint32_t, QXmppOmemoStorage::SignedPreKeyPair> signedPreKeyPairs;
+
+    // recipient JID mapped to device ID mapped to device
+    QHash<QString, QHash<uint32_t, QXmppOmemoStorage::Device>> devices;
+};
+
+///
+/// Constructs an OMEMO memory storage.
+///
+QXmppOmemoMemoryStorage::QXmppOmemoMemoryStorage()
+    : d(new QXmppOmemoMemoryStoragePrivate)
+{
+}
+
+QXmppOmemoMemoryStorage::~QXmppOmemoMemoryStorage() = default;
+
+/// \cond
+QFuture<QXmppOmemoStorage::OmemoData> QXmppOmemoMemoryStorage::allData()
+{
+    return makeReadyFuture(std::move(OmemoData { d->ownDevice,
+                                                 d->signedPreKeyPairs,
+                                                 d->preKeyPairs,
+                                                 d->devices }));
+}
+
+QFuture<void> QXmppOmemoMemoryStorage::setOwnDevice(const std::optional<OwnDevice> &device)
+{
+    d->ownDevice = device;
+    return makeReadyFuture();
+}
+
+QFuture<void> QXmppOmemoMemoryStorage::addSignedPreKeyPair(const uint32_t keyId, const SignedPreKeyPair &keyPair)
+{
+    d->signedPreKeyPairs.insert(keyId, keyPair);
+    return makeReadyFuture();
+}
+
+QFuture<void> QXmppOmemoMemoryStorage::removeSignedPreKeyPair(const uint32_t keyId)
+{
+    d->signedPreKeyPairs.remove(keyId);
+    return makeReadyFuture();
+}
+
+QFuture<void> QXmppOmemoMemoryStorage::addPreKeyPairs(const QHash<uint32_t, QByteArray> &keyPairs)
+{
+    d->preKeyPairs.insert(keyPairs);
+    return makeReadyFuture();
+}
+
+QFuture<void> QXmppOmemoMemoryStorage::removePreKeyPair(const uint32_t keyId)
+{
+    d->preKeyPairs.remove(keyId);
+    return makeReadyFuture();
+}
+
+QFuture<void> QXmppOmemoMemoryStorage::addDevice(const QString &jid, const uint32_t deviceId, const QXmppOmemoStorage::Device &device)
+{
+    d->devices[jid].insert(deviceId, device);
+    return makeReadyFuture();
+}
+
+QFuture<void> QXmppOmemoMemoryStorage::removeDevice(const QString &jid, const uint32_t deviceId)
+{
+    auto &devices = d->devices[jid];
+    devices.remove(deviceId);
+
+    // Remove the container for the passed JID if the container stores no
+    // devices anymore.
+    if (devices.isEmpty()) {
+        d->devices.remove(jid);
+    }
+
+    return makeReadyFuture();
+}
+
+QFuture<void> QXmppOmemoMemoryStorage::removeDevices(const QString &jid)
+{
+    d->devices.remove(jid);
+    return makeReadyFuture();
+}
+
+QFuture<void> QXmppOmemoMemoryStorage::resetAll()
+{
+    d.reset(new QXmppOmemoMemoryStoragePrivate());
+    return makeReadyFuture();
+}
+/// \endcond