From a3486fd0e9786c47564ce8173a2e4039135b10f9 Mon Sep 17 00:00:00 2001
From: Alexey Rusakov <Kitsune-Ral@users.sf.net>
Date: Sun, 15 May 2022 22:08:09 +0200
Subject: Simplify QOlmSession::matchesInboundSession*()

There's no particular use in letting `QOlmError` out, only to confirm
that, well, `QOlmError` is just another form of no-match.
---
 autotests/testolmsession.cpp |  2 +-
 lib/connection.cpp           |  3 +--
 lib/e2ee/qolmsession.cpp     | 43 +++++++++++++++++--------------------------
 3 files changed, 19 insertions(+), 29 deletions(-)

diff --git a/autotests/testolmsession.cpp b/autotests/testolmsession.cpp
index 5436c392..2674b60b 100644
--- a/autotests/testolmsession.cpp
+++ b/autotests/testolmsession.cpp
@@ -45,7 +45,7 @@ void TestOlmSession::olmEncryptDecrypt()
     const auto encrypted = outboundSession->encrypt("Hello world!");
     if (encrypted.type() == QOlmMessage::PreKey) {
         QOlmMessage m(encrypted); // clone
-        QVERIFY(std::get<bool>(inboundSession->matchesInboundSession(m)));
+        QVERIFY(inboundSession->matchesInboundSession(m));
     }
 
     const auto decrypted = std::get<QString>(inboundSession->decrypt(encrypted));
diff --git a/lib/connection.cpp b/lib/connection.cpp
index 511b64e2..955b5b1a 100644
--- a/lib/connection.cpp
+++ b/lib/connection.cpp
@@ -226,8 +226,7 @@ public:
     {
         Q_ASSERT(message.type() == QOlmMessage::PreKey);
         for(auto& session : olmSessions[senderKey]) {
-            const auto matches = session->matchesInboundSessionFrom(senderKey, message);
-            if(std::holds_alternative<bool>(matches) && std::get<bool>(matches)) {
+            if (session->matchesInboundSessionFrom(senderKey, message)) {
                 qCDebug(E2EE) << "Found inbound session";
                 const auto result = session->decrypt(message);
                 if(std::holds_alternative<QString>(result)) {
diff --git a/lib/e2ee/qolmsession.cpp b/lib/e2ee/qolmsession.cpp
index 531a6696..5ccbfd40 100644
--- a/lib/e2ee/qolmsession.cpp
+++ b/lib/e2ee/qolmsession.cpp
@@ -209,42 +209,33 @@ bool QOlmSession::hasReceivedMessage() const
     return olm_session_has_received_message(m_session);
 }
 
-std::variant<bool, QOlmError> QOlmSession::matchesInboundSession(const QOlmMessage &preKeyMessage) const
+bool QOlmSession::matchesInboundSession(const QOlmMessage& preKeyMessage) const
 {
     Q_ASSERT(preKeyMessage.type() == QOlmMessage::Type::PreKey);
     QByteArray oneTimeKeyBuf(preKeyMessage.data());
-    const auto matchesResult = olm_matches_inbound_session(m_session, oneTimeKeyBuf.data(), oneTimeKeyBuf.length());
+    const auto maybeMatches =
+        olm_matches_inbound_session(m_session, oneTimeKeyBuf.data(),
+                                    oneTimeKeyBuf.length());
 
-    if (matchesResult == olm_error()) {
+    if (maybeMatches == olm_error()) {
         return lastError(m_session);
     }
-    switch (matchesResult) {
-        case 0:
-            return false;
-        case 1:
-            return true;
-        default:
-            return QOlmError::Unknown;
-    }
+    return maybeMatches == 1;
 }
-std::variant<bool, QOlmError> QOlmSession::matchesInboundSessionFrom(const QString &theirIdentityKey, const QOlmMessage &preKeyMessage) const
+
+bool QOlmSession::matchesInboundSessionFrom(
+    const QString& theirIdentityKey, const QOlmMessage& preKeyMessage) const
 {
     const auto theirIdentityKeyBuf = theirIdentityKey.toUtf8();
     auto oneTimeKeyMessageBuf = preKeyMessage.toCiphertext();
-    const auto error = olm_matches_inbound_session_from(m_session, theirIdentityKeyBuf.data(), theirIdentityKeyBuf.length(),
-            oneTimeKeyMessageBuf.data(), oneTimeKeyMessageBuf.length());
-
-    if (error == olm_error()) {
-        return lastError(m_session);
-    }
-    switch (error) {
-        case 0:
-            return false;
-        case 1:
-            return true;
-        default:
-            return QOlmError::Unknown;
-    }
+    const auto maybeMatches = olm_matches_inbound_session_from(
+        m_session, theirIdentityKeyBuf.data(), theirIdentityKeyBuf.length(),
+        oneTimeKeyMessageBuf.data(), oneTimeKeyMessageBuf.length());
+
+    if (maybeMatches == olm_error())
+        qCWarning(E2EE) << "Error matching an inbound session:"
+                        << olm_session_last_error(m_session);
+    return maybeMatches == 1;
 }
 
 QOlmSession::QOlmSession(OlmSession *session)
-- 
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