Replace the Auth and Auth::TLS singletons

Use a builder pattern for creation and validation, in a manner that
allows also other authentication methods to be added in the future
besides the current TLS/SSL.

The main Auth instances are built early and then passed by not_null
const pointers, to avoid passing temporaries, replacing the previous
Auth::TLS instances passed by simple nullable const pointers. Where
needed, these passed Auth instances are also stored, by const ref.

Tests also build Auth instances as needed, either with the default
'no certification' or from the test environment arguments.

1 files changed, 20 insertions, 22 deletions

diff --git a/test/utils/test_env.hpp b/test/utils/test_env.hpp
index d9c60fb8..30eba26c 100644
--- a/test/utils/test_env.hpp
+++ b/test/utils/test_env.hpp
@@ -16,6 +16,7 @@
 #define INCLUDED_SRC_TEST_UTILS_TEST_ENV_HPP
 
 #include <cstdlib>
+#include <filesystem>
 #include <map>
 #include <optional>
 #include <sstream>
@@ -62,31 +63,28 @@ static inline void ReadCompatibilityFromEnv() {
                : std::make_optional(std::string{serve_address});
 }
 
-[[nodiscard]] static inline auto ReadTLSAuthArgsFromEnv() -> bool {
+[[nodiscard]] static inline auto ReadTLSAuthCACertFromEnv()
+    -> std::optional<std::filesystem::path> {
     auto* ca_cert = std::getenv("TLS_CA_CERT");
+    return ca_cert == nullptr
+               ? std::nullopt
+               : std::make_optional(std::filesystem::path(ca_cert));
+}
+
+[[nodiscard]] static inline auto ReadTLSAuthClientCertFromEnv()
+    -> std::optional<std::filesystem::path> {
     auto* client_cert = std::getenv("TLS_CLIENT_CERT");
+    return client_cert == nullptr
+               ? std::nullopt
+               : std::make_optional(std::filesystem::path(client_cert));
+}
+
+[[nodiscard]] static inline auto ReadTLSAuthClientKeyFromEnv()
+    -> std::optional<std::filesystem::path> {
     auto* client_key = std::getenv("TLS_CLIENT_KEY");
-    if (ca_cert != nullptr) {
-        if (not Auth::TLS::Instance().SetCACertificate(ca_cert)) {
-            return false;
-        }
-    }
-    if (client_cert != nullptr) {
-        if (not Auth::TLS::Instance().SetClientCertificate(client_cert)) {
-            return false;
-        }
-    }
-    if (client_key != nullptr) {
-        if (not Auth::TLS::Instance().SetClientKey(client_key)) {
-            return false;
-        }
-    }
-    if (Auth::Instance().GetAuthMethod() == AuthMethod::kTLS) {
-        if (not Auth::TLS::Instance().Validate()) {
-            return false;
-        }
-    }
-    return true;
+    return client_key == nullptr
+               ? std::nullopt
+               : std::make_optional(std::filesystem::path(client_key));
 }
 
 [[nodiscard]] static inline auto ReadRemoteServeReposFromEnv()