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, 2 insertions, 5 deletions

diff --git a/lib/e2ee/qolmutility.h b/lib/e2ee/qolmutility.h
index a12af49a..5f6bcdc5 100644
--- a/lib/e2ee/qolmutility.h
+++ b/lib/e2ee/qolmutility.h
@@ -4,15 +4,12 @@
 
 #pragma once
 
-#include <variant>
-#include "e2ee/qolmerrors.h"
+#include "e2ee/e2ee.h"
 
 struct OlmUtility;
 
 namespace Quotient {
 
-class QOlmSession;
-
 //! Allows you to make use of crytographic hashing via SHA-2 and
 //! verifying ed25519 signatures.
 class QUOTIENT_API QOlmUtility
@@ -32,7 +29,7 @@ public:
     //! \param key QByteArray The public part of the ed25519 key that signed the message.
     //! \param message QByteArray The message that was signed.
     //! \param signature QByteArray The signature of the message.
-    std::variant<bool, QOlmError> ed25519Verify(const QByteArray &key,
+    QOlmExpected<bool> ed25519Verify(const QByteArray &key,
             const QByteArray &message, const QByteArray &signature);
 
 private: