QOlmExpected and associated refactoring

As mentioned in the commit introducing `Expected`, `QOlmExpected` is
simply an alias for `Expected<T, QOlmError>`. This simplifies quite
a few function signatures in `QOlm*` classes and collapses unwieldy
`std::holds_alternative<>`/`std::get<>` constructs into a neat
contextual bool cast and an invocation of `operator*` or
`value()`/`error()` accessors that don't need to specify the type.

While refactoring the code, I found a couple of cases of mismatching
`uint32_t` and `qint32_t` in return values; a couple of cases where
`decrypt()` returns `QString` which is in fact `QByteArray` (e.g., in
`QOlmSession::decrypt()`); there's a repetitive algorithm in
`Connection::Private::sessionDecryptPrekey()` and
`sessionDecryptGeneral()`

1 files changed, 8 insertions, 0 deletions

diff --git a/lib/e2ee/e2ee.h b/lib/e2ee/e2ee.h
index 268cb525..8e433d60 100644
--- a/lib/e2ee/e2ee.h
+++ b/lib/e2ee/e2ee.h
@@ -6,6 +6,8 @@
 #pragma once
 
 #include "converters.h"
+#include "expected.h"
+#include "qolmerrors.h"
 #include "quotient_common.h"
 
 #include <QtCore/QMetaType>
@@ -55,6 +57,12 @@ using QOlmSessionPtr = std::unique_ptr<QOlmSession>;
 class QOlmInboundGroupSession;
 using QOlmInboundGroupSessionPtr = std::unique_ptr<QOlmInboundGroupSession>;
 
+class QOlmOutboundGroupSession;
+using QOlmOutboundGroupSessionPtr = std::unique_ptr<QOlmOutboundGroupSession>;
+
+template <typename T>
+using QOlmExpected = Expected<T, QOlmError>;
+
 struct IdentityKeys
 {
     QByteArray curve25519;