LibRequests: Add hooks to handle RequestServer death

Author: https://github.com/trflynn89
Commit: 6f4be4791a
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/5796

Libraries/LibRequests/NetworkError.h

@@ -20,6 +20,7 @@ enum class NetworkError {
     SSLVerificationFailed,
     MalformedUrl,
     InvalidContentEncoding,
+    RequestServerDied,
     Unknown,
 };
 
@@ -44,6 +45,8 @@ constexpr StringView network_error_to_string(NetworkError network_error)
         return "The URL is not formatted properly"sv;
     case NetworkError::InvalidContentEncoding:
         return "Response could not be decoded with its Content-Encoding"sv;
+    case NetworkError::RequestServerDied:
+        return "RequestServer is currently unavailable"sv;
     case NetworkError::Unknown:
         return "An unexpected network error occurred"sv;
     }

Libraries/LibRequests/RequestClient.cpp

@@ -19,8 +19,12 @@ RequestClient::~RequestClient() = default;
 
 void RequestClient::die()
 {
-    // FIXME: Gracefully handle this, or relaunch and reconnect to RequestServer.
+    for (auto& [id, request] : m_requests) {
-    warnln("\033[31;1m {} Lost connection to RequestServer\033[0m", Core::System::getpid());
+        if (request)
+            request->did_finish({}, {}, {}, NetworkError::RequestServerDied);
+    }
+
+    m_requests.clear();
 }
 
 void RequestClient::ensure_connection(URL::URL const& url, ::RequestServer::CacheLevel cache_level)

Libraries/LibRequests/RequestClient.h

@@ -39,6 +39,8 @@ public:
     bool stop_request(Badge<Request>, Request&);
     bool set_certificate(Badge<Request>, Request&, ByteString, ByteString);
 
+    Function<void()> on_request_server_died;
+
 private:
     virtual void die() override;