LibIPC+Everywhere: Introduce an IPC Transport abstraction

This abstraction will help us to support multiple IPC transport
mechanisms going forward. For now, we only have a TransportSocket that
implements the same behavior we previously had, using Unix Sockets for
IPC.

Ladybird/AppKit/Application/Application.mm

@@ -134,7 +134,7 @@ static ErrorOr<NonnullRefPtr<ImageDecoderClient::Client>> launch_new_image_decod
     auto web_worker_paths = TRY(get_paths_for_helper_process("WebWorker"sv));
     auto worker_client = TRY(launch_web_worker_process(web_worker_paths, *m_request_server_client));
 
-    return worker_client->dup_socket();
+    return worker_client->clone_transport();
 }
 
 #pragma mark - NSApplication

Ladybird/Headless/HeadlessWebView.cpp

@@ -33,7 +33,7 @@ HeadlessWebView::HeadlessWebView(Core::AnonymousBuffer theme, Gfx::IntSize viewp
         auto web_worker_paths = MUST(get_paths_for_helper_process("WebWorker"sv));
         auto worker_client = MUST(launch_web_worker_process(web_worker_paths, Application::request_client()));
 
-        return worker_client->dup_socket();
+        return worker_client->clone_transport();
     };
 }
 

Ladybird/Qt/WebContentView.cpp

@@ -135,7 +135,7 @@ WebContentView::WebContentView(QWidget* window, RefPtr<WebView::WebContentClient
     on_request_worker_agent = [&]() {
         auto& request_server_client = static_cast<Ladybird::Application*>(QApplication::instance())->request_server_client;
         auto worker_client = MUST(launch_web_worker_process(MUST(get_paths_for_helper_process("WebWorker"sv)), *request_server_client));
-        return worker_client->dup_socket();
+        return worker_client->clone_transport();
     };
 
     m_select_dropdown = new QMenu("Select Dropdown", this);

Ladybird/WebContent/main.cpp

@@ -188,8 +188,10 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     if (maybe_autoplay_allowlist_error.is_error())
         dbgln("Failed to load autoplay allowlist: {}", maybe_autoplay_allowlist_error.error());
 
+    static_assert(IsSame<IPC::Transport, IPC::TransportSocket>, "Need to handle other IPC transports here");
+
     auto webcontent_socket = TRY(Core::take_over_socket_from_system_server("WebContent"sv));
-    auto webcontent_client = TRY(WebContent::ConnectionFromClient::try_create(move(webcontent_socket)));
+    auto webcontent_client = TRY(WebContent::ConnectionFromClient::try_create(IPC::Transport(move(webcontent_socket))));
 
     webcontent_client->on_image_decoder_connection = [&](auto& socket_file) {
         auto maybe_error = reinitialize_image_decoder(socket_file);
@@ -250,10 +252,12 @@ static ErrorOr<void> load_autoplay_allowlist(StringView config_path)
 
 ErrorOr<void> initialize_resource_loader(int request_server_socket)
 {
+    static_assert(IsSame<IPC::Transport, IPC::TransportSocket>, "Need to handle other IPC transports here");
+
     auto socket = TRY(Core::LocalSocket::adopt_fd(request_server_socket));
     TRY(socket->set_blocking(true));
 
-    auto request_client = TRY(try_make_ref_counted<Requests::RequestClient>(move(socket)));
+    auto request_client = TRY(try_make_ref_counted<Requests::RequestClient>(IPC::Transport(move(socket))));
     Web::ResourceLoader::initialize(move(request_client));
 
     return {};
@@ -261,10 +265,11 @@ ErrorOr<void> initialize_resource_loader(int request_server_socket)
 
 ErrorOr<void> initialize_image_decoder(int image_decoder_socket)
 {
+    static_assert(IsSame<IPC::Transport, IPC::TransportSocket>, "Need to handle other IPC transports here");
     auto socket = TRY(Core::LocalSocket::adopt_fd(image_decoder_socket));
     TRY(socket->set_blocking(true));
 
-    auto new_client = TRY(try_make_ref_counted<ImageDecoderClient::Client>(move(socket)));
+    auto new_client = TRY(try_make_ref_counted<ImageDecoderClient::Client>(IPC::Transport(move(socket))));
 
     Web::Platform::ImageCodecPlugin::install(*new Ladybird::ImageCodecPlugin(move(new_client)));
 
@@ -273,10 +278,12 @@ ErrorOr<void> initialize_image_decoder(int image_decoder_socket)
 
 ErrorOr<void> reinitialize_image_decoder(IPC::File const& image_decoder_socket)
 {
+    static_assert(IsSame<IPC::Transport, IPC::TransportSocket>, "Need to handle other IPC transports here");
+
     auto socket = TRY(Core::LocalSocket::adopt_fd(image_decoder_socket.take_fd()));
     TRY(socket->set_blocking(true));
 
-    auto new_client = TRY(try_make_ref_counted<ImageDecoderClient::Client>(move(socket)));
+    auto new_client = TRY(try_make_ref_counted<ImageDecoderClient::Client>(IPC::Transport(move(socket))));
 
     static_cast<Ladybird::ImageCodecPlugin&>(Web::Platform::ImageCodecPlugin::the()).set_client(move(new_client));
 

Ladybird/WebWorker/main.cpp

@@ -73,10 +73,12 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
 
 static ErrorOr<void> initialize_resource_loader(int request_server_socket)
 {
+    static_assert(IsSame<IPC::Transport, IPC::TransportSocket>, "Need to handle other IPC transports here");
+
     auto socket = TRY(Core::LocalSocket::adopt_fd(request_server_socket));
     TRY(socket->set_blocking(true));
 
-    auto request_client = TRY(try_make_ref_counted<Requests::RequestClient>(move(socket)));
+    auto request_client = TRY(try_make_ref_counted<Requests::RequestClient>(IPC::Transport(move(socket))));
     Web::ResourceLoader::initialize(move(request_client));
 
     return {};

Userland/Libraries/LibIPC/CMakeLists.txt

@@ -5,5 +5,9 @@ set(SOURCES
     Message.cpp
 )
 
+if (UNIX)
+    list(APPEND SOURCES TransportSocket.cpp)
+endif()
+
 serenity_lib(LibIPC ipc)
 target_link_libraries(LibIPC PRIVATE LibCore LibURL LibThreading)

Userland/Libraries/LibIPC/Connection.cpp

@@ -14,22 +14,19 @@
 
 namespace IPC {
 
-ConnectionBase::ConnectionBase(IPC::Stub& local_stub, NonnullOwnPtr<Core::LocalSocket> socket, u32 local_endpoint_magic)
+ConnectionBase::ConnectionBase(IPC::Stub& local_stub, Transport transport, u32 local_endpoint_magic)
     : m_local_stub(local_stub)
-    , m_socket(move(socket))
+    , m_transport(move(transport))
     , m_local_endpoint_magic(local_endpoint_magic)
 {
-    socklen_t socket_buffer_size = 128 * KiB;
-    (void)Core::System::setsockopt(m_socket->fd().value(), SOL_SOCKET, SO_SNDBUF, &socket_buffer_size, sizeof(socket_buffer_size));
-    (void)Core::System::setsockopt(m_socket->fd().value(), SOL_SOCKET, SO_RCVBUF, &socket_buffer_size, sizeof(socket_buffer_size));
-
     m_responsiveness_timer = Core::Timer::create_single_shot(3000, [this] { may_have_become_unresponsive(); });
-    m_socket->on_ready_to_read = [this] {
+
+    m_transport.set_up_read_hook([this] {
         NonnullRefPtr protect = *this;
         // FIXME: Do something about errors.
         (void)drain_messages_from_peer();
         handle_messages();
-    };
+    });
 
     m_send_queue = adopt_ref(*new SendQueue);
     m_send_thread = Threading::Thread::construct([this, queue = m_send_queue]() -> intptr_t {
@@ -46,7 +43,7 @@ ConnectionBase::ConnectionBase(IPC::Stub& local_stub, NonnullOwnPtr<Core::LocalS
             auto message = queue->messages.take_first();
             queue->mutex.unlock();
 
-            if (auto result = message.transfer_message(*m_socket); result.is_error()) {
+            if (auto result = message.transfer_message(m_transport); result.is_error()) {
                 dbgln("ConnectionBase::send_thread: {}", result.error());
                 continue;
             }
@@ -68,7 +65,7 @@ ConnectionBase::~ConnectionBase()
 
 bool ConnectionBase::is_open() const
 {
-    return m_socket->is_open();
+    return m_transport.is_open();
 }
 
 ErrorOr<void> ConnectionBase::post_message(Message const& message)
@@ -80,7 +77,7 @@ ErrorOr<void> ConnectionBase::post_message(MessageBuffer buffer)
 {
     // NOTE: If this connection is being shut down, but has not yet been destroyed,
     //       the socket will be closed. Don't try to send more messages.
-    if (!m_socket->is_open())
+    if (!m_transport.is_open())
         return Error::from_string_literal("Trying to post_message during IPC shutdown");
 
     {
@@ -95,7 +92,7 @@ ErrorOr<void> ConnectionBase::post_message(MessageBuffer buffer)
 
 void ConnectionBase::shutdown()
 {
-    m_socket->close();
+    m_transport.close();
     die();
 }
 
@@ -125,19 +122,12 @@ void ConnectionBase::handle_messages()
     }
 }
 
-void ConnectionBase::wait_for_socket_to_become_readable()
+void ConnectionBase::wait_for_transport_to_become_readable()
 {
-    auto maybe_did_become_readable = m_socket->can_read_without_blocking(-1);
+    m_transport.wait_until_readable();
-    if (maybe_did_become_readable.is_error()) {
-        dbgln("ConnectionBase::wait_for_socket_to_become_readable: {}", maybe_did_become_readable.error());
-        warnln("ConnectionBase::wait_for_socket_to_become_readable: {}", maybe_did_become_readable.error());
-        VERIFY_NOT_REACHED();
-    }
-
-    VERIFY(maybe_did_become_readable.value());
 }
 
-ErrorOr<Vector<u8>> ConnectionBase::read_as_much_as_possible_from_socket_without_blocking()
+ErrorOr<Vector<u8>> ConnectionBase::read_as_much_as_possible_from_transport_without_blocking()
 {
     Vector<u8> bytes;
 
@@ -146,9 +136,6 @@ ErrorOr<Vector<u8>> ConnectionBase::read_as_much_as_possible_from_socket_without
         m_unprocessed_bytes.clear();
     }
 
-    u8 buffer[4096];
-    Vector<int> received_fds;
-
     bool should_shut_down = false;
     auto schedule_shutdown = [this, &should_shut_down]() {
         should_shut_down = true;
@@ -157,34 +144,11 @@ ErrorOr<Vector<u8>> ConnectionBase::read_as_much_as_possible_from_socket_without
         });
     };
 
-    while (m_socket->is_open()) {
+    auto&& [new_bytes, received_fds] = m_transport.read_as_much_as_possible_without_blocking(move(schedule_shutdown));
-        auto maybe_bytes_read = m_socket->receive_message({ buffer, 4096 }, MSG_DONTWAIT, received_fds);
+    bytes.append(new_bytes.data(), new_bytes.size());
-        if (maybe_bytes_read.is_error()) {
-            auto error = maybe_bytes_read.release_error();
-            if (error.is_syscall() && error.code() == EAGAIN) {
-                break;
-            }
 
-            if (error.is_syscall() && error.code() == ECONNRESET) {
-                schedule_shutdown();
-                break;
-            }
-
-            dbgln("ConnectionBase::read_as_much_as_possible_from_socket_without_blocking: {}", error);
-            warnln("ConnectionBase::read_as_much_as_possible_from_socket_without_blocking: {}", error);
-            VERIFY_NOT_REACHED();
-        }
-
-        auto bytes_read = maybe_bytes_read.release_value();
-        if (bytes_read.is_empty()) {
-            schedule_shutdown();
-            break;
-        }
-
-        bytes.append(bytes_read.data(), bytes_read.size());
     for (auto const& fd : received_fds)
         m_unprocessed_fds.enqueue(IPC::File::adopt_fd(fd));
-    }
 
     if (!bytes.is_empty()) {
         m_responsiveness_timer->stop();
@@ -198,7 +162,7 @@ ErrorOr<Vector<u8>> ConnectionBase::read_as_much_as_possible_from_socket_without
 
 ErrorOr<void> ConnectionBase::drain_messages_from_peer()
 {
-    auto bytes = TRY(read_as_much_as_possible_from_socket_without_blocking());
+    auto bytes = TRY(read_as_much_as_possible_from_transport_without_blocking());
 
     size_t index = 0;
     try_parse_messages(bytes, index);
@@ -236,10 +200,10 @@ OwnPtr<IPC::Message> ConnectionBase::wait_for_specific_endpoint_message_impl(u32
                 return m_unprocessed_messages.take(i);
         }
 
-        if (!m_socket->is_open())
+        if (!is_open())
             break;
 
-        wait_for_socket_to_become_readable();
+        wait_for_transport_to_become_readable();
         if (drain_messages_from_peer().is_error())
             break;
     }

Userland/Libraries/LibIPC/Connection.h

@@ -12,6 +12,7 @@
 #include <LibCore/EventReceiver.h>
 #include <LibIPC/File.h>
 #include <LibIPC/Forward.h>
+#include <LibIPC/Transport.h>
 #include <LibThreading/ConditionVariable.h>
 #include <LibThreading/MutexProtected.h>
 #include <LibThreading/Thread.h>
@@ -30,10 +31,10 @@ public:
     void shutdown();
     virtual void die() { }
 
-    Core::LocalSocket& socket() { return *m_socket; }
+    Transport& transport() { return m_transport; }
 
 protected:
-    explicit ConnectionBase(IPC::Stub&, NonnullOwnPtr<Core::LocalSocket>, u32 local_endpoint_magic);
+    explicit ConnectionBase(IPC::Stub&, Transport, u32 local_endpoint_magic);
 
     virtual void may_have_become_unresponsive() { }
     virtual void did_become_responsive() { }
@@ -41,8 +42,8 @@ protected:
     virtual OwnPtr<Message> try_parse_message(ReadonlyBytes, Queue<IPC::File>&) = 0;
 
     OwnPtr<IPC::Message> wait_for_specific_endpoint_message_impl(u32 endpoint_magic, int message_id);
-    void wait_for_socket_to_become_readable();
+    void wait_for_transport_to_become_readable();
-    ErrorOr<Vector<u8>> read_as_much_as_possible_from_socket_without_blocking();
+    ErrorOr<Vector<u8>> read_as_much_as_possible_from_transport_without_blocking();
     ErrorOr<void> drain_messages_from_peer();
     void try_parse_messages(Vector<u8> const& bytes, size_t& index);
 
@@ -51,7 +52,7 @@ protected:
 
     IPC::Stub& m_local_stub;
 
-    NonnullOwnPtr<Core::LocalSocket> m_socket;
+    Transport m_transport;
 
     RefPtr<Core::Timer> m_responsiveness_timer;
 
@@ -75,8 +76,8 @@ protected:
 template<typename LocalEndpoint, typename PeerEndpoint>
 class Connection : public ConnectionBase {
 public:
-    Connection(IPC::Stub& local_stub, NonnullOwnPtr<Core::LocalSocket> socket)
+    Connection(IPC::Stub& local_stub, Transport transport)
-        : ConnectionBase(local_stub, move(socket), LocalEndpoint::static_magic())
+        : ConnectionBase(local_stub, move(transport), LocalEndpoint::static_magic())
     {
     }
 

Userland/Libraries/LibIPC/ConnectionFromClient.h

@@ -26,16 +26,16 @@ public:
     using ServerStub = typename ServerEndpoint::Stub;
     using IPCProxy = typename ClientEndpoint::template Proxy<ServerEndpoint>;
 
-    ConnectionFromClient(ServerStub& stub, NonnullOwnPtr<Core::LocalSocket> socket, int client_id)
+    ConnectionFromClient(ServerStub& stub, Transport transport, int client_id)
-        : IPC::Connection<ServerEndpoint, ClientEndpoint>(stub, move(socket))
+        : IPC::Connection<ServerEndpoint, ClientEndpoint>(stub, move(transport))
         , ClientEndpoint::template Proxy<ServerEndpoint>(*this, {})
         , m_client_id(client_id)
     {
-        VERIFY(this->socket().is_open());
+        this->transport().set_up_read_hook([this] {
-        this->socket().on_ready_to_read = [this] {
+            NonnullRefPtr protect = *this;
             // FIXME: Do something about errors.
             (void)this->drain_messages_from_peer();
-        };
+        });
     }
 
     virtual ~ConnectionFromClient() override = default;

Userland/Libraries/LibIPC/ConnectionToServer.h

@@ -22,7 +22,7 @@ public:
         /* We want to rate-limit our clients */                                                                        \
         TRY(socket->set_blocking(true));                                                                               \
                                                                                                                        \
-        return adopt_nonnull_ref_or_enomem(new (nothrow) Klass(move(socket), forward<Args>(args)...)); \
+        return adopt_nonnull_ref_or_enomem(new (nothrow) Klass(IPC::Transport(move(socket)), forward<Args>(args)...)); \
     }
 
 template<typename ClientEndpoint, typename ServerEndpoint>
@@ -33,8 +33,8 @@ public:
     using ClientStub = typename ClientEndpoint::Stub;
     using IPCProxy = typename ServerEndpoint::template Proxy<ClientEndpoint>;
 
-    ConnectionToServer(ClientStub& local_endpoint, NonnullOwnPtr<Core::LocalSocket> socket)
+    ConnectionToServer(ClientStub& local_endpoint, Transport transport)
-        : Connection<ClientEndpoint, ServerEndpoint>(local_endpoint, move(socket))
+        : Connection<ClientEndpoint, ServerEndpoint>(local_endpoint, move(transport))
         , ServerEndpoint::template Proxy<ClientEndpoint>(*this, {})
     {
     }

Userland/Libraries/LibIPC/Message.cpp

@@ -5,10 +5,7 @@
  */
 
 #include <AK/Checked.h>
-#include <LibCore/Socket.h>
-#include <LibCore/System.h>
 #include <LibIPC/Message.h>
-#include <sched.h>
 
 namespace IPC {
 
@@ -38,7 +35,7 @@ ErrorOr<void> MessageBuffer::append_file_descriptor(int fd)
     return {};
 }
 
-ErrorOr<void> MessageBuffer::transfer_message(Core::LocalSocket& socket)
+ErrorOr<void> MessageBuffer::transfer_message(Transport& transport)
 {
     Checked<MessageSizeType> checked_message_size { m_data.size() };
     checked_message_size -= sizeof(MessageSizeType);
@@ -58,49 +55,7 @@ ErrorOr<void> MessageBuffer::transfer_message(Core::LocalSocket& socket)
         }
     }
 
-    ReadonlyBytes bytes_to_write { m_data.span() };
+    TRY(transport.transfer(m_data.span(), raw_fds));
-
-    while (!bytes_to_write.is_empty()) {
-        ErrorOr<ssize_t> maybe_nwritten = 0;
-        if (num_fds_to_transfer > 0) {
-            maybe_nwritten = socket.send_message(bytes_to_write, 0, raw_fds);
-            if (!maybe_nwritten.is_error())
-                num_fds_to_transfer = 0;
-        } else {
-            maybe_nwritten = socket.write_some(bytes_to_write);
-        }
-
-        if (maybe_nwritten.is_error()) {
-            if (auto error = maybe_nwritten.release_error(); error.is_errno() && (error.code() == EAGAIN || error.code() == EWOULDBLOCK)) {
-                Vector<struct pollfd, 1> pollfds;
-                if (pollfds.is_empty())
-                    pollfds.append({ .fd = socket.fd().value(), .events = POLLOUT, .revents = 0 });
-
-                ErrorOr<int> result { 0 };
-                do {
-                    constexpr u32 POLL_TIMEOUT_MS = 100;
-                    result = Core::System::poll(pollfds, POLL_TIMEOUT_MS);
-                } while (result.is_error() && result.error().code() == EINTR);
-
-                if (!result.is_error() && result.value() != 0)
-                    continue;
-
-                switch (error.code()) {
-                case EPIPE:
-                    return Error::from_string_literal("IPC::transfer_message: Disconnected from peer");
-                case EAGAIN:
-                    return Error::from_string_literal("IPC::transfer_message: Timed out waiting for socket to become writable");
-                default:
-                    return Error::from_syscall("IPC::transfer_message write"sv, -error.code());
-                }
-            } else {
-                return error;
-            }
-        }
-
-        bytes_to_write = bytes_to_write.slice(maybe_nwritten.value());
-    }
-
     return {};
 }
 

Userland/Libraries/LibIPC/Message.h

@@ -12,6 +12,7 @@
 #include <AK/RefPtr.h>
 #include <AK/Vector.h>
 #include <LibCore/Forward.h>
+#include <LibIPC/Transport.h>
 #include <unistd.h>
 
 namespace IPC {
@@ -44,7 +45,7 @@ public:
 
     ErrorOr<void> append_file_descriptor(int fd);
 
-    ErrorOr<void> transfer_message(Core::LocalSocket& socket);
+    ErrorOr<void> transfer_message(Transport& socket);
 
 private:
     Vector<u8, 1024> m_data;

Userland/Libraries/LibIPC/MultiServer.h

@@ -37,7 +37,7 @@ private:
         m_server->on_accept = [&](auto client_socket) {
             auto client_id = ++m_next_client_id;
 
-            auto client = IPC::new_client_connection<ConnectionFromClientType>(move(client_socket), client_id);
+            auto client = IPC::new_client_connection<ConnectionFromClientType>(IPC::Transport(move(client_socket)), client_id);
             if (on_new_client)
                 on_new_client(*client);
         };

Userland/Libraries/LibIPC/SingleServer.h

@@ -16,7 +16,7 @@ template<typename ConnectionFromClientType>
 ErrorOr<NonnullRefPtr<ConnectionFromClientType>> take_over_accepted_client_from_system_server()
 {
     auto socket = TRY(Core::take_over_socket_from_system_server());
-    return IPC::new_client_connection<ConnectionFromClientType>(move(socket));
+    return IPC::new_client_connection<ConnectionFromClientType>(IPC::Transport(move(socket)));
 }
 
 }

Userland/Libraries/LibIPC/Transport.h

@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2024, Andrew Kaster <andrew@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Platform.h>
+
+#if !defined(AK_OS_WINDOWS)
+#    include <LibIPC/TransportSocket.h>
+#endif
+
+namespace IPC {
+
+#if !defined(AK_OS_WINDOWS)
+// Unix Domain Sockets
+using Transport = TransportSocket;
+#else
+#    error "LibIPC Transport has not been ported to this platform"
+#endif
+
+}

Userland/Libraries/LibIPC/TransportSocket.cpp

@@ -0,0 +1,151 @@
+/*
+ * Copyright (c) 2024, Andrew Kaster <andrew@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/NonnullOwnPtr.h>
+#include <LibCore/Socket.h>
+#include <LibCore/System.h>
+#include <LibIPC/File.h>
+#include <LibIPC/TransportSocket.h>
+
+namespace IPC {
+
+TransportSocket::TransportSocket(NonnullOwnPtr<Core::LocalSocket> socket)
+    : m_socket(move(socket))
+{
+    socklen_t socket_buffer_size = 128 * KiB;
+    (void)Core::System::setsockopt(m_socket->fd().value(), SOL_SOCKET, SO_SNDBUF, &socket_buffer_size, sizeof(socket_buffer_size));
+    (void)Core::System::setsockopt(m_socket->fd().value(), SOL_SOCKET, SO_RCVBUF, &socket_buffer_size, sizeof(socket_buffer_size));
+}
+
+TransportSocket::~TransportSocket() = default;
+
+void TransportSocket::set_up_read_hook(Function<void()> hook)
+{
+    VERIFY(m_socket->is_open());
+    m_socket->on_ready_to_read = move(hook);
+}
+
+bool TransportSocket::is_open() const
+{
+    return m_socket->is_open();
+}
+
+void TransportSocket::close()
+{
+    m_socket->close();
+}
+
+void TransportSocket::wait_until_readable()
+{
+    auto maybe_did_become_readable = m_socket->can_read_without_blocking(-1);
+    if (maybe_did_become_readable.is_error()) {
+        dbgln("TransportSocket::wait_until_readable: {}", maybe_did_become_readable.error());
+        warnln("TransportSocket::wait_until_readable: {}", maybe_did_become_readable.error());
+        VERIFY_NOT_REACHED();
+    }
+
+    VERIFY(maybe_did_become_readable.value());
+}
+
+ErrorOr<void> TransportSocket::transfer(ReadonlyBytes bytes_to_write, Vector<int, 1> const& unowned_fds)
+{
+    auto num_fds_to_transfer = unowned_fds.size();
+    while (!bytes_to_write.is_empty()) {
+        ErrorOr<ssize_t> maybe_nwritten = 0;
+        if (num_fds_to_transfer > 0) {
+            maybe_nwritten = m_socket->send_message(bytes_to_write, 0, unowned_fds);
+            if (!maybe_nwritten.is_error())
+                num_fds_to_transfer = 0;
+        } else {
+            maybe_nwritten = m_socket->write_some(bytes_to_write);
+        }
+
+        if (maybe_nwritten.is_error()) {
+            if (auto error = maybe_nwritten.release_error(); error.is_errno() && (error.code() == EAGAIN || error.code() == EWOULDBLOCK)) {
+
+                // FIXME: Refactor this to pass the unwritten bytes back to the caller to send 'later'
+                //        or next time the socket is writable
+                Vector<struct pollfd, 1> pollfds;
+                if (pollfds.is_empty())
+                    pollfds.append({ .fd = m_socket->fd().value(), .events = POLLOUT, .revents = 0 });
+
+                ErrorOr<int> result { 0 };
+                do {
+                    constexpr u32 POLL_TIMEOUT_MS = 100;
+                    result = Core::System::poll(pollfds, POLL_TIMEOUT_MS);
+                } while (result.is_error() && result.error().code() == EINTR);
+
+                if (!result.is_error() && result.value() != 0)
+                    continue;
+
+                switch (error.code()) {
+                case EPIPE:
+                    return Error::from_string_literal("IPC::transfer_message: Disconnected from peer");
+                case EAGAIN:
+                    return Error::from_string_literal("IPC::transfer_message: Timed out waiting for socket to become writable");
+                default:
+                    return Error::from_syscall("IPC::transfer_message write"sv, -error.code());
+                }
+            } else {
+                return error;
+            }
+        }
+
+        bytes_to_write = bytes_to_write.slice(maybe_nwritten.value());
+    }
+    return {};
+}
+
+TransportSocket::ReadResult TransportSocket::read_as_much_as_possible_without_blocking(Function<void()> schedule_shutdown)
+{
+    u8 buffer[4096];
+
+    ReadResult result;
+    auto received_fds = Vector<int> {};
+    auto& bytes = result.bytes;
+
+    while (is_open()) {
+        auto maybe_bytes_read = m_socket->receive_message({ buffer, 4096 }, MSG_DONTWAIT, received_fds);
+        if (maybe_bytes_read.is_error()) {
+            auto error = maybe_bytes_read.release_error();
+            if (error.is_syscall() && error.code() == EAGAIN) {
+                break;
+            }
+
+            if (error.is_syscall() && error.code() == ECONNRESET) {
+                schedule_shutdown();
+                break;
+            }
+
+            dbgln("TransportSocket::read_as_much_as_possible_without_blocking: {}", error);
+            warnln("TransportSocket::read_as_much_as_possible_without_blocking: {}", error);
+            VERIFY_NOT_REACHED();
+        }
+
+        auto bytes_read = maybe_bytes_read.release_value();
+        if (bytes_read.is_empty()) {
+            schedule_shutdown();
+            break;
+        }
+
+        bytes.append(bytes_read.data(), bytes_read.size());
+        result.fds.append(received_fds.data(), received_fds.size());
+    }
+
+    return result;
+}
+
+ErrorOr<int> TransportSocket::release_underlying_transport_for_transfer()
+{
+    return m_socket->release_fd();
+}
+
+ErrorOr<IPC::File> TransportSocket::clone_for_transfer()
+{
+    return IPC::File::clone_fd(m_socket->fd().value());
+}
+
+}

Userland/Libraries/LibIPC/TransportSocket.h

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2024, Andrew Kaster <andrew@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibCore/File.h>
+
+namespace IPC {
+
+class TransportSocket {
+    AK_MAKE_NONCOPYABLE(TransportSocket);
+    AK_MAKE_DEFAULT_MOVABLE(TransportSocket);
+
+public:
+    explicit TransportSocket(NonnullOwnPtr<Core::LocalSocket> socket);
+    ~TransportSocket();
+
+    void set_up_read_hook(Function<void()>);
+    bool is_open() const;
+    void close();
+
+    void wait_until_readable();
+
+    ErrorOr<void> transfer(ReadonlyBytes, Vector<int, 1> const& unowned_fds);
+
+    struct [[nodiscard]] ReadResult {
+        Vector<u8> bytes;
+        Vector<int> fds;
+    };
+    ReadResult read_as_much_as_possible_without_blocking(Function<void()> schedule_shutdown);
+
+    // Obnoxious name to make it clear that this is a dangerous operation.
+    ErrorOr<int> release_underlying_transport_for_transfer();
+
+    ErrorOr<IPC::File> clone_for_transfer();
+
+private:
+    NonnullOwnPtr<Core::LocalSocket> m_socket;
+};
+
+}

Userland/Libraries/LibImageDecoderClient/Client.cpp

@@ -9,8 +9,8 @@
 
 namespace ImageDecoderClient {
 
-Client::Client(NonnullOwnPtr<Core::LocalSocket> socket)
+Client::Client(IPC::Transport transport)
-    : IPC::ConnectionToServer<ImageDecoderClientEndpoint, ImageDecoderServerEndpoint>(*this, move(socket))
+    : IPC::ConnectionToServer<ImageDecoderClientEndpoint, ImageDecoderServerEndpoint>(*this, move(transport))
 {
 }
 

Userland/Libraries/LibImageDecoderClient/Client.h

@@ -32,7 +32,7 @@ class Client final
     IPC_CLIENT_CONNECTION(Client, "/tmp/session/%sid/portal/image"sv);
 
 public:
-    Client(NonnullOwnPtr<Core::LocalSocket>);
+    Client(IPC::Transport);
 
     NonnullRefPtr<Core::Promise<DecodedImage>> decode_image(ReadonlyBytes, Function<ErrorOr<void>(DecodedImage&)> on_resolved, Function<void(Error&)> on_rejected, Optional<Gfx::IntSize> ideal_size = {}, Optional<ByteString> mime_type = {});
 

Userland/Libraries/LibRequests/RequestClient.cpp

@@ -9,8 +9,8 @@
 
 namespace Requests {
 
-RequestClient::RequestClient(NonnullOwnPtr<Core::LocalSocket> socket)
+RequestClient::RequestClient(IPC::Transport transport)
-    : IPC::ConnectionToServer<RequestClientEndpoint, RequestServerEndpoint>(*this, move(socket))
+    : IPC::ConnectionToServer<RequestClientEndpoint, RequestServerEndpoint>(*this, move(transport))
 {
 }
 

Userland/Libraries/LibRequests/RequestClient.h

@@ -24,7 +24,7 @@ class RequestClient final
     IPC_CLIENT_CONNECTION(RequestClient, "/tmp/session/%sid/portal/request"sv)
 
 public:
-    explicit RequestClient(NonnullOwnPtr<Core::LocalSocket>);
+    explicit RequestClient(IPC::Transport);
     virtual ~RequestClient() override;
 
     RefPtr<Request> start_request(ByteString const& method, URL::URL const&, HTTP::HeaderMap const& request_headers = {}, ReadonlyBytes request_body = {}, Core::ProxyData const& = {});

Userland/Libraries/LibWeb/HTML/MessagePort.cpp

@@ -12,6 +12,7 @@
 #include <LibIPC/Decoder.h>
 #include <LibIPC/Encoder.h>
 #include <LibIPC/File.h>
+#include <LibIPC/Transport.h>
 #include <LibWeb/Bindings/ExceptionOrUtils.h>
 #include <LibWeb/Bindings/Intrinsics.h>
 #include <LibWeb/Bindings/MessagePortPrototype.h>
@@ -71,6 +72,11 @@ void MessagePort::visit_edges(Cell::Visitor& visitor)
     visitor.visit(m_worker_event_target);
 }
 
+bool MessagePort::is_entangled() const
+{
+    return m_transport.has_value();
+}
+
 void MessagePort::set_worker_event_target(JS::NonnullGCPtr<DOM::EventTarget> target)
 {
     m_worker_event_target = target;
@@ -91,10 +97,14 @@ WebIDL::ExceptionOr<void> MessagePort::transfer_steps(HTML::TransferDataHolder&
         m_remote_port->m_has_been_shipped = true;
 
         // 2. Set dataHolder.[[RemotePort]] to remotePort.
-        auto fd = MUST(m_socket->release_fd());
+        if constexpr (IsSame<IPC::Transport, IPC::TransportSocket>) {
-        m_socket = nullptr;
+            auto fd = MUST(m_transport->release_underlying_transport_for_transfer());
+            m_transport = {};
             data_holder.fds.append(IPC::File::adopt_fd(fd));
             data_holder.data.append(IPC_FILE_TAG);
+        } else {
+            VERIFY(false && "Don't know how to transfer IPC::Transport type");
+        }
     }
 
     // 4. Otherwise, set dataHolder.[[RemotePort]] to null.
@@ -118,12 +128,16 @@ WebIDL::ExceptionOr<void> MessagePort::transfer_receiving_steps(HTML::TransferDa
     //     (This will disentangle dataHolder.[[RemotePort]] from the original port that was transferred.)
     auto fd_tag = data_holder.data.take_first();
     if (fd_tag == IPC_FILE_TAG) {
+        if constexpr (IsSame<IPC::Transport, IPC::TransportSocket>) {
             auto fd = data_holder.fds.take_first();
-        m_socket = MUST(Core::LocalSocket::adopt_fd(fd.take_fd()));
+            m_transport = IPC::Transport(MUST(Core::LocalSocket::adopt_fd(fd.take_fd())));
 
-        m_socket->on_ready_to_read = [strong_this = JS::make_handle(this)]() {
+            m_transport->set_up_read_hook([strong_this = JS::make_handle(this)]() {
-            strong_this->read_from_socket();
+                strong_this->read_from_transport();
-        };
+            });
+        } else {
+            VERIFY(false && "Don't know how to receive IPC::Transport type");
+        }
     } else if (fd_tag != 0) {
         dbgln("Unexpected byte {:x} in MessagePort transfer data", fd_tag);
         VERIFY_NOT_REACHED();
@@ -138,7 +152,7 @@ void MessagePort::disentangle()
         m_remote_port->m_remote_port = nullptr;
     m_remote_port = nullptr;
 
-    m_socket = nullptr;
+    m_transport = {};
 
     m_worker_event_target = nullptr;
 }
@@ -160,6 +174,7 @@ void MessagePort::entangle_with(MessagePort& remote_port)
     remote_port.m_remote_port = this;
     m_remote_port = &remote_port;
 
+    // FIXME: Abstract such that we can entangle different transport types
     auto create_paired_sockets = []() -> Array<NonnullOwnPtr<Core::LocalSocket>, 2> {
         int fds[2] = {};
         MUST(Core::System::socketpair(AF_LOCAL, SOCK_STREAM, 0, fds));
@@ -174,16 +189,16 @@ void MessagePort::entangle_with(MessagePort& remote_port)
     };
 
     auto sockets = create_paired_sockets();
-    m_socket = move(sockets[0]);
+    m_transport = IPC::Transport(move(sockets[0]));
-    m_remote_port->m_socket = move(sockets[1]);
+    m_remote_port->m_transport = IPC::Transport(move(sockets[1]));
 
-    m_socket->on_ready_to_read = [strong_this = JS::make_handle(this)]() {
+    m_transport->set_up_read_hook([strong_this = JS::make_handle(this)]() {
-        strong_this->read_from_socket();
+        strong_this->read_from_transport();
-    };
+    });
 
-    m_remote_port->m_socket->on_ready_to_read = [remote_port = JS::make_handle(m_remote_port)]() {
+    m_remote_port->m_transport->set_up_read_hook([remote_port = JS::make_handle(m_remote_port)]() {
-        remote_port->read_from_socket();
+        remote_port->read_from_transport();
-    };
+    });
 }
 
 // https://html.spec.whatwg.org/multipage/web-messaging.html#dom-messageport-postmessage-options
@@ -243,7 +258,7 @@ WebIDL::ExceptionOr<void> MessagePort::message_port_post_message_steps(JS::GCPtr
     // 6. If targetPort is null, or if doomed is true, then return.
     // IMPLEMENTATION DEFINED: Actually check the socket here, not the target port.
     //     If there's no target message port in the same realm, we still want to send the message over IPC
-    if (!m_socket || doomed) {
+    if (!m_transport.has_value() || doomed) {
         return {};
     }
 
@@ -253,13 +268,13 @@ WebIDL::ExceptionOr<void> MessagePort::message_port_post_message_steps(JS::GCPtr
     return {};
 }
 
-ErrorOr<void> MessagePort::send_message_on_socket(SerializedTransferRecord const& serialize_with_transfer_result)
+ErrorOr<void> MessagePort::send_message_on_transport(SerializedTransferRecord const& serialize_with_transfer_result)
 {
     IPC::MessageBuffer buffer;
     IPC::Encoder encoder(buffer);
     MUST(encoder.encode(serialize_with_transfer_result));
 
-    TRY(buffer.transfer_message(*m_socket));
+    TRY(buffer.transfer_message(*m_transport));
     return {};
 }
 
@@ -267,9 +282,9 @@ void MessagePort::post_port_message(SerializedTransferRecord serialize_with_tran
 {
     // FIXME: Use the correct task source?
     queue_global_task(Task::Source::PostedMessage, relevant_global_object(*this), JS::create_heap_function(heap(), [this, serialize_with_transfer_result = move(serialize_with_transfer_result)]() mutable {
-        if (!m_socket || !m_socket->is_open())
+        if (!m_transport.has_value() || !m_transport->is_open())
             return;
-        if (auto result = send_message_on_socket(serialize_with_transfer_result); result.is_error()) {
+        if (auto result = send_message_on_transport(serialize_with_transfer_result); result.is_error()) {
             dbgln("Failed to post message: {}", result.error());
             disentangle();
         }
@@ -320,18 +335,13 @@ ErrorOr<MessagePort::ParseDecision> MessagePort::parse_message()
     return ParseDecision::ParseNextMessage;
 }
 
-void MessagePort::read_from_socket()
+void MessagePort::read_from_transport()
 {
-    u8 buffer[4096] {};
+    auto&& [bytes, fds] = m_transport->read_as_much_as_possible_without_blocking([this] {
-
+        queue_global_task(Task::Source::PostedMessage, relevant_global_object(*this), JS::create_heap_function(heap(), [this] {
-    Vector<int> fds;
+            this->close();
-    // FIXME: What if pending bytes is > 4096? Should we loop here?
+        }));
-    auto maybe_bytes = m_socket->receive_message(buffer, MSG_NOSIGNAL, fds);
+    });
-    if (maybe_bytes.is_error()) {
-        dbgln("MessagePort::read_from_socket(): Failed to receive message: {}", maybe_bytes.error());
-        return;
-    }
-    auto bytes = maybe_bytes.release_value();
 
     m_buffered_data.append(bytes.data(), bytes.size());
 
@@ -406,7 +416,7 @@ void MessagePort::start()
     if (!is_entangled())
         return;
 
-    VERIFY(m_socket);
+    VERIFY(m_transport.has_value());
 
     // TODO: The start() method steps are to enable this's port message queue, if it is not already enabled.
 }

Userland/Libraries/LibWeb/HTML/MessagePort.h

@@ -11,6 +11,7 @@
 #include <AK/Weakable.h>
 #include <LibCore/Socket.h>
 #include <LibIPC/File.h>
+#include <LibIPC/Transport.h>
 #include <LibWeb/Bindings/Transferable.h>
 #include <LibWeb/DOM/EventTarget.h>
 #include <LibWeb/Forward.h>
@@ -69,13 +70,13 @@ private:
     virtual void initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;
 
-    bool is_entangled() const { return static_cast<bool>(m_socket); }
+    bool is_entangled() const;
 
     WebIDL::ExceptionOr<void> message_port_post_message_steps(JS::GCPtr<MessagePort> target_port, JS::Value message, StructuredSerializeOptions const& options);
     void post_message_task_steps(SerializedTransferRecord&);
     void post_port_message(SerializedTransferRecord);
-    ErrorOr<void> send_message_on_socket(SerializedTransferRecord const&);
+    ErrorOr<void> send_message_on_transport(SerializedTransferRecord const&);
-    void read_from_socket();
+    void read_from_transport();
 
     enum class ParseDecision {
         NotEnoughData,
@@ -89,7 +90,7 @@ private:
     // https://html.spec.whatwg.org/multipage/web-messaging.html#has-been-shipped
     bool m_has_been_shipped { false };
 
-    OwnPtr<Core::LocalSocket> m_socket;
+    Optional<IPC::Transport> m_transport;
 
     enum class SocketState : u8 {
         Header,

Userland/Libraries/LibWeb/HTML/WorkerAgent.cpp

@@ -35,10 +35,14 @@ void WorkerAgent::initialize(JS::Realm& realm)
     // NOTE: This blocking IPC call may launch another process.
     //    If spinning the event loop for this can cause other javascript to execute, we're in trouble.
     auto worker_socket_file = Bindings::host_defined_page(realm).client().request_worker_agent();
+
     auto worker_socket = MUST(Core::LocalSocket::adopt_fd(worker_socket_file.take_fd()));
     MUST(worker_socket->set_blocking(true));
+    static_assert(IsSame<IPC::Transport, IPC::TransportSocket>, "Handle other IPC::Transport types here");
 
-    m_worker_ipc = make_ref_counted<WebWorkerClient>(move(worker_socket));
+    auto transport = IPC::Transport(move(worker_socket));
+
+    m_worker_ipc = make_ref_counted<WebWorkerClient>(move(transport));
 
     m_worker_ipc->async_start_dedicated_worker(m_url, m_worker_options.type, m_worker_options.credentials, m_worker_options.name, move(data_holder), m_outside_settings->serialize());
 }

Userland/Libraries/LibWeb/Worker/WebWorkerClient.cpp

@@ -20,14 +20,14 @@ void WebWorkerClient::did_close_worker()
         on_worker_close();
 }
 
-WebWorkerClient::WebWorkerClient(NonnullOwnPtr<Core::LocalSocket> socket)
+WebWorkerClient::WebWorkerClient(IPC::Transport transport)
-    : IPC::ConnectionToServer<WebWorkerClientEndpoint, WebWorkerServerEndpoint>(*this, move(socket))
+    : IPC::ConnectionToServer<WebWorkerClientEndpoint, WebWorkerServerEndpoint>(*this, move(transport))
 {
 }
 
-IPC::File WebWorkerClient::dup_socket()
+IPC::File WebWorkerClient::clone_transport()
 {
-    return MUST(IPC::File::clone_fd(socket().fd().value()));
+    return MUST(m_transport.clone_for_transfer());
 }
 
 }

Userland/Libraries/LibWeb/Worker/WebWorkerClient.h

@@ -19,13 +19,13 @@ class WebWorkerClient final
     IPC_CLIENT_CONNECTION(WebWorkerClient, "/tmp/session/%sid/portal/webworker"sv);
 
 public:
-    explicit WebWorkerClient(NonnullOwnPtr<Core::LocalSocket>);
+    explicit WebWorkerClient(IPC::Transport);
 
     virtual void did_close_worker() override;
 
     Function<void()> on_worker_close;
 
-    IPC::File dup_socket();
+    IPC::File clone_transport();
 
 private:
     virtual void die() override;

Userland/Libraries/LibWebView/ChromeProcess.cpp

@@ -22,7 +22,7 @@ class UIProcessClient final
     C_OBJECT(UIProcessClient);
 
 private:
-    UIProcessClient(NonnullOwnPtr<Core::LocalSocket>);
+    explicit UIProcessClient(IPC::Transport);
 };
 
 ErrorOr<ChromeProcess::ProcessDisposition> ChromeProcess::connect(Vector<ByteString> const& raw_urls, NewWindow new_window)
@@ -48,7 +48,8 @@ ErrorOr<ChromeProcess::ProcessDisposition> ChromeProcess::connect(Vector<ByteStr
 ErrorOr<void> ChromeProcess::connect_as_client(ByteString const& socket_path, Vector<ByteString> const& raw_urls, NewWindow new_window)
 {
     auto socket = TRY(Core::LocalSocket::connect(socket_path));
-    auto client = UIProcessClient::construct(move(socket));
+    static_assert(IsSame<IPC::Transport, IPC::TransportSocket>, "Need to handle other IPC transports here");
+    auto client = UIProcessClient::construct(IPC::Transport(move(socket)));
 
     if (new_window == NewWindow::Yes) {
         if (!client->send_sync_but_allow_failure<Messages::UIProcessServer::CreateNewWindow>(raw_urls))
@@ -63,10 +64,13 @@ ErrorOr<void> ChromeProcess::connect_as_client(ByteString const& socket_path, Ve
 
 ErrorOr<void> ChromeProcess::connect_as_server(ByteString const& socket_path)
 {
+    static_assert(IsSame<IPC::Transport, IPC::TransportSocket>, "Need to handle other IPC transports here");
+
     auto socket_fd = TRY(Process::create_ipc_socket(socket_path));
     m_socket_path = socket_path;
     auto local_server = TRY(Core::LocalServer::try_create());
     TRY(local_server->take_over_fd(socket_fd));
+
     m_server_connection = TRY(IPC::MultiServer<UIProcessConnectionFromClient>::try_create(move(local_server)));
 
     m_server_connection->on_new_client = [this](auto& client) {
@@ -95,13 +99,13 @@ ChromeProcess::~ChromeProcess()
         MUST(Core::System::unlink(m_socket_path));
 }
 
-UIProcessClient::UIProcessClient(NonnullOwnPtr<Core::LocalSocket> socket)
+UIProcessClient::UIProcessClient(IPC::Transport transport)
-    : IPC::ConnectionToServer<UIProcessClientEndpoint, UIProcessServerEndpoint>(*this, move(socket))
+    : IPC::ConnectionToServer<UIProcessClientEndpoint, UIProcessServerEndpoint>(*this, move(transport))
 {
 }
 
-UIProcessConnectionFromClient::UIProcessConnectionFromClient(NonnullOwnPtr<Core::LocalSocket> socket, int client_id)
+UIProcessConnectionFromClient::UIProcessConnectionFromClient(IPC::Transport transport, int client_id)
-    : IPC::ConnectionFromClient<UIProcessClientEndpoint, UIProcessServerEndpoint>(*this, move(socket), client_id)
+    : IPC::ConnectionFromClient<UIProcessClientEndpoint, UIProcessServerEndpoint>(*this, move(transport), client_id)
 {
     s_connections.set(client_id, *this);
 }

Userland/Libraries/LibWebView/ChromeProcess.h

@@ -10,7 +10,6 @@
 #include <AK/Function.h>
 #include <AK/OwnPtr.h>
 #include <AK/Types.h>
-#include <LibCore/Socket.h>
 #include <LibIPC/ConnectionFromClient.h>
 #include <LibIPC/Forward.h>
 #include <LibIPC/MultiServer.h>
@@ -33,7 +32,7 @@ public:
     Function<void(Vector<URL::URL> const&)> on_new_window;
 
 private:
-    UIProcessConnectionFromClient(NonnullOwnPtr<Core::LocalSocket>, int client_id);
+    UIProcessConnectionFromClient(IPC::Transport, int client_id);
 
     virtual void create_new_tab(Vector<ByteString> const& urls) override;
     virtual void create_new_window(Vector<ByteString> const& urls) override;

Userland/Libraries/LibWebView/Process.cpp

@@ -6,6 +6,7 @@
 
 #include <LibCore/Environment.h>
 #include <LibCore/Process.h>
+#include <LibCore/Socket.h>
 #include <LibCore/StandardPaths.h>
 #include <LibWebView/Process.h>
 
@@ -24,8 +25,10 @@ Process::~Process()
         m_connection->shutdown();
 }
 
-ErrorOr<Process::ProcessAndIPCSocket> Process::spawn_and_connect_to_process(Core::ProcessSpawnOptions const& options)
+ErrorOr<Process::ProcessAndIPCTransport> Process::spawn_and_connect_to_process(Core::ProcessSpawnOptions const& options)
 {
+    static_assert(IsSame<IPC::Transport, IPC::TransportSocket>, "Need to handle other IPC transports here");
+
     int socket_fds[2] {};
     TRY(Core::System::socketpair(AF_LOCAL, SOCK_STREAM, 0, socket_fds));
 
@@ -44,7 +47,7 @@ ErrorOr<Process::ProcessAndIPCSocket> Process::spawn_and_connect_to_process(Core
     guard_fd_0.disarm();
     TRY(ipc_socket->set_blocking(true));
 
-    return ProcessAndIPCSocket { move(process), move(ipc_socket) };
+    return ProcessAndIPCTransport { move(process), IPC::Transport(move(ipc_socket)) };
 }
 
 ErrorOr<Optional<pid_t>> Process::get_process_pid(StringView process_name, StringView pid_path)

Userland/Libraries/LibWebView/Process.h

@@ -9,8 +9,8 @@
 #include <AK/String.h>
 #include <AK/WeakPtr.h>
 #include <LibCore/Process.h>
-#include <LibCore/Socket.h>
 #include <LibIPC/Connection.h>
+#include <LibIPC/Transport.h>
 #include <LibWebView/ProcessType.h>
 
 namespace WebView {
@@ -52,11 +52,11 @@ public:
     static ErrorOr<int> create_ipc_socket(ByteString const& socket_path);
 
 private:
-    struct ProcessAndIPCSocket {
+    struct ProcessAndIPCTransport {
         Core::Process process;
-        NonnullOwnPtr<Core::LocalSocket> socket;
+        IPC::Transport transport;
     };
-    static ErrorOr<ProcessAndIPCSocket> spawn_and_connect_to_process(Core::ProcessSpawnOptions const& options);
+    static ErrorOr<ProcessAndIPCTransport> spawn_and_connect_to_process(Core::ProcessSpawnOptions const& options);
 
     Core::Process m_process;
     ProcessType m_type;
@@ -73,8 +73,8 @@ struct Process::ProcessAndClient {
 template<typename ClientType, typename... ClientArguments>
 ErrorOr<Process::ProcessAndClient<ClientType>> Process::spawn(ProcessType type, Core::ProcessSpawnOptions const& options, ClientArguments&&... client_arguments)
 {
-    auto [core_process, socket] = TRY(spawn_and_connect_to_process(options));
+    auto [core_process, transport] = TRY(spawn_and_connect_to_process(options));
-    auto client = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) ClientType { move(socket), forward<ClientArguments>(client_arguments)... }));
+    auto client = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) ClientType { move(transport), forward<ClientArguments>(client_arguments)... }));
 
     return ProcessAndClient { Process { type, client, move(core_process) }, client };
 }

Userland/Libraries/LibWebView/WebContentClient.cpp

@@ -23,8 +23,8 @@ Optional<ViewImplementation&> WebContentClient::view_for_pid_and_page_id(pid_t p
     return {};
 }
 
-WebContentClient::WebContentClient(NonnullOwnPtr<Core::LocalSocket> socket, ViewImplementation& view)
+WebContentClient::WebContentClient(IPC::Transport transport, ViewImplementation& view)
-    : IPC::ConnectionToServer<WebContentClientEndpoint, WebContentServerEndpoint>(*this, move(socket))
+    : IPC::ConnectionToServer<WebContentClientEndpoint, WebContentServerEndpoint>(*this, move(transport))
 {
     s_clients.set(this);
     m_views.set(0, &view);

Userland/Libraries/LibWebView/WebContentClient.h

@@ -9,6 +9,7 @@
 #include <AK/HashMap.h>
 #include <AK/SourceLocation.h>
 #include <LibIPC/ConnectionToServer.h>
+#include <LibIPC/Transport.h>
 #include <LibWeb/CSS/StyleSheetIdentifier.h>
 #include <LibWeb/HTML/ActivateTab.h>
 #include <LibWeb/HTML/FileFilter.h>
@@ -35,7 +36,7 @@ public:
 
     static size_t client_count() { return s_clients.size(); }
 
-    WebContentClient(NonnullOwnPtr<Core::LocalSocket>, ViewImplementation&);
+    WebContentClient(IPC::Transport, ViewImplementation&);
     ~WebContentClient();
 
     void register_view(u64 page_id, ViewImplementation&);

Userland/Services/ImageDecoder/ConnectionFromClient.cpp

@@ -17,8 +17,8 @@ namespace ImageDecoder {
 static HashMap<int, RefPtr<ConnectionFromClient>> s_connections;
 static IDAllocator s_client_ids;
 
-ConnectionFromClient::ConnectionFromClient(NonnullOwnPtr<Core::LocalSocket> socket)
+ConnectionFromClient::ConnectionFromClient(IPC::Transport transport)
-    : IPC::ConnectionFromClient<ImageDecoderClientEndpoint, ImageDecoderServerEndpoint>(*this, move(socket), s_client_ids.allocate())
+    : IPC::ConnectionFromClient<ImageDecoderClientEndpoint, ImageDecoderServerEndpoint>(*this, move(transport), s_client_ids.allocate())
 {
     s_connections.set(client_id(), *this);
 }
@@ -55,7 +55,7 @@ ErrorOr<IPC::File> ConnectionFromClient::connect_new_client()
 
     auto client_socket = client_socket_or_error.release_value();
     // Note: A ref is stored in the static s_connections map
-    auto client = adopt_ref(*new ConnectionFromClient(move(client_socket)));
+    auto client = adopt_ref(*new ConnectionFromClient(IPC::Transport(move(client_socket))));
 
     return IPC::File::adopt_fd(socket_fds[1]);
 }

Userland/Services/ImageDecoder/ConnectionFromClient.h

@@ -36,7 +36,7 @@ public:
 private:
     using Job = Threading::BackgroundAction<DecodeResult>;
 
-    explicit ConnectionFromClient(NonnullOwnPtr<Core::LocalSocket>);
+    explicit ConnectionFromClient(IPC::Transport);
 
     virtual Messages::ImageDecoderServer::DecodeImageResponse decode_image(Core::AnonymousBuffer const&, Optional<Gfx::IntSize> const& ideal_size, Optional<ByteString> const& mime_type) override;
     virtual void cancel_decoding(i64 image_id) override;

Userland/Services/RequestServer/ConnectionFromClient.cpp

@@ -175,8 +175,8 @@ int ConnectionFromClient::on_timeout_callback(void*, long timeout_ms, void* user
     return 0;
 }
 
-ConnectionFromClient::ConnectionFromClient(NonnullOwnPtr<Core::LocalSocket> socket)
+ConnectionFromClient::ConnectionFromClient(IPC::Transport transport)
-    : IPC::ConnectionFromClient<RequestClientEndpoint, RequestServerEndpoint>(*this, move(socket), s_client_ids.allocate())
+    : IPC::ConnectionFromClient<RequestClientEndpoint, RequestServerEndpoint>(*this, move(transport), s_client_ids.allocate())
 {
     s_connections.set(client_id(), *this);
 
@@ -215,6 +215,8 @@ void ConnectionFromClient::die()
 
 Messages::RequestServer::ConnectNewClientResponse ConnectionFromClient::connect_new_client()
 {
+    static_assert(IsSame<IPC::Transport, IPC::TransportSocket>, "Need to handle other IPC transports here");
+
     int socket_fds[2] {};
     if (auto err = Core::System::socketpair(AF_LOCAL, SOCK_STREAM, 0, socket_fds); err.is_error()) {
         dbgln("Failed to create client socketpair: {}", err.error());
@@ -230,7 +232,7 @@ Messages::RequestServer::ConnectNewClientResponse ConnectionFromClient::connect_
     }
     auto client_socket = client_socket_or_error.release_value();
     // Note: A ref is stored in the static s_connections map
-    auto client = adopt_ref(*new ConnectionFromClient(move(client_socket)));
+    auto client = adopt_ref(*new ConnectionFromClient(IPC::Transport(move(client_socket))));
 
     return IPC::File::adopt_fd(socket_fds[1]);
 }

Userland/Services/RequestServer/ConnectionFromClient.h

@@ -30,7 +30,7 @@ public:
     void did_request_certificates(Badge<Request>, Request&);
 
 private:
-    explicit ConnectionFromClient(NonnullOwnPtr<Core::LocalSocket>);
+    explicit ConnectionFromClient(IPC::Transport);
 
     virtual Messages::RequestServer::ConnectNewClientResponse connect_new_client() override;
     virtual Messages::RequestServer::IsSupportedProtocolResponse is_supported_protocol(ByteString const&) override;

Userland/Services/WebContent/ConnectionFromClient.cpp

@@ -53,8 +53,8 @@
 
 namespace WebContent {
 
-ConnectionFromClient::ConnectionFromClient(NonnullOwnPtr<Core::LocalSocket> socket)
+ConnectionFromClient::ConnectionFromClient(IPC::Transport transport)
-    : IPC::ConnectionFromClient<WebContentClientEndpoint, WebContentServerEndpoint>(*this, move(socket), 1)
+    : IPC::ConnectionFromClient<WebContentClientEndpoint, WebContentServerEndpoint>(*this, move(transport), 1)
     , m_page_host(PageHost::create(*this))
 {
     m_input_event_queue_timer = Web::Platform::Timer::create_single_shot(0, [this] { process_next_input_event(); });

Userland/Services/WebContent/ConnectionFromClient.h

@@ -42,15 +42,13 @@ public:
 
     void request_file(u64 page_id, Web::FileRequest);
 
-    Optional<int> fd() { return socket().fd(); }
-
     PageHost& page_host() { return *m_page_host; }
     PageHost const& page_host() const { return *m_page_host; }
 
     Function<void(IPC::File const&)> on_image_decoder_connection;
 
 private:
-    explicit ConnectionFromClient(NonnullOwnPtr<Core::LocalSocket>);
+    explicit ConnectionFromClient(IPC::Transport);
 
     Optional<PageClient&> page(u64 index, SourceLocation = SourceLocation::current());
     Optional<PageClient const&> page(u64 index, SourceLocation = SourceLocation::current()) const;

Userland/Services/WebContent/WebDriverConnection.cpp

@@ -184,6 +184,8 @@ static bool fire_an_event(FlyString name, Optional<Web::DOM::Element&> target)
 
 ErrorOr<NonnullRefPtr<WebDriverConnection>> WebDriverConnection::connect(Web::PageClient& page_client, ByteString const& webdriver_ipc_path)
 {
+    static_assert(IsSame<IPC::Transport, IPC::TransportSocket>, "Need to handle other IPC transports here");
+
     dbgln_if(WEBDRIVER_DEBUG, "Trying to connect to {}", webdriver_ipc_path);
     auto socket = TRY(Core::LocalSocket::connect(webdriver_ipc_path));
 
@@ -191,11 +193,11 @@ ErrorOr<NonnullRefPtr<WebDriverConnection>> WebDriverConnection::connect(Web::Pa
     page_client.page().set_should_block_pop_ups(false);
 
     dbgln_if(WEBDRIVER_DEBUG, "Connected to WebDriver");
-    return adopt_nonnull_ref_or_enomem(new (nothrow) WebDriverConnection(move(socket), page_client));
+    return adopt_nonnull_ref_or_enomem(new (nothrow) WebDriverConnection(IPC::Transport(move(socket)), page_client));
 }
 
-WebDriverConnection::WebDriverConnection(NonnullOwnPtr<Core::LocalSocket> socket, Web::PageClient& page_client)
+WebDriverConnection::WebDriverConnection(IPC::Transport transport, Web::PageClient& page_client)
-    : IPC::ConnectionToServer<WebDriverClientEndpoint, WebDriverServerEndpoint>(*this, move(socket))
+    : IPC::ConnectionToServer<WebDriverClientEndpoint, WebDriverServerEndpoint>(*this, move(transport))
 {
     set_current_top_level_browsing_context(page_client.page().top_level_browsing_context());
 }

Userland/Services/WebContent/WebDriverConnection.h

@@ -14,6 +14,7 @@
 #include <AK/String.h>
 #include <LibGfx/Rect.h>
 #include <LibIPC/ConnectionToServer.h>
+#include <LibIPC/Transport.h>
 #include <LibJS/Forward.h>
 #include <LibJS/Heap/MarkedVector.h>
 #include <LibWeb/Forward.h>
@@ -37,7 +38,7 @@ public:
     void visit_edges(JS::Cell::Visitor&);
 
 private:
-    WebDriverConnection(NonnullOwnPtr<Core::LocalSocket> socket, Web::PageClient& page_client);
+    WebDriverConnection(IPC::Transport transport, Web::PageClient& page_client);
 
     virtual void die() override { }
 

Userland/Services/WebDriver/Session.cpp

@@ -56,6 +56,8 @@ Session::~Session()
 
 ErrorOr<NonnullRefPtr<Core::LocalServer>> Session::create_server(NonnullRefPtr<ServerPromise> promise)
 {
+    static_assert(IsSame<IPC::Transport, IPC::TransportSocket>, "Need to handle other IPC transports here");
+
     dbgln("Listening for WebDriver connection on {}", *m_web_content_socket_path);
 
     (void)Core::System::unlink(*m_web_content_socket_path);
@@ -64,7 +66,7 @@ ErrorOr<NonnullRefPtr<Core::LocalServer>> Session::create_server(NonnullRefPtr<S
     server->listen(*m_web_content_socket_path);
 
     server->on_accept = [this, promise](auto client_socket) {
-        auto maybe_connection = adopt_nonnull_ref_or_enomem(new (nothrow) WebContentConnection(move(client_socket)));
+        auto maybe_connection = adopt_nonnull_ref_or_enomem(new (nothrow) WebContentConnection(IPC::Transport(move(client_socket))));
         if (maybe_connection.is_error()) {
             promise->resolve(maybe_connection.release_error());
             return;

Userland/Services/WebDriver/WebContentConnection.cpp

@@ -9,8 +9,8 @@
 
 namespace WebDriver {
 
-WebContentConnection::WebContentConnection(NonnullOwnPtr<Core::LocalSocket> socket)
+WebContentConnection::WebContentConnection(IPC::Transport transport)
-    : IPC::ConnectionFromClient<WebDriverClientEndpoint, WebDriverServerEndpoint>(*this, move(socket), 1)
+    : IPC::ConnectionFromClient<WebDriverClientEndpoint, WebDriverServerEndpoint>(*this, move(transport), 1)
 {
 }
 

Userland/Services/WebDriver/WebContentConnection.h

@@ -7,6 +7,7 @@
 #pragma once
 
 #include <LibIPC/ConnectionFromClient.h>
+#include <LibIPC/Transport.h>
 #include <WebContent/WebDriverClientEndpoint.h>
 #include <WebContent/WebDriverServerEndpoint.h>
 
@@ -18,7 +19,7 @@ class WebContentConnection
     : public IPC::ConnectionFromClient<WebDriverClientEndpoint, WebDriverServerEndpoint> {
     C_OBJECT_ABSTRACT(WebContentConnection)
 public:
-    WebContentConnection(NonnullOwnPtr<Core::LocalSocket> socket);
+    explicit WebContentConnection(IPC::Transport transport);
 
     Function<void()> on_close;
     Function<void(Web::WebDriver::Response)> on_script_executed;

Userland/Services/WebWorker/ConnectionFromClient.cpp

@@ -45,8 +45,8 @@ void ConnectionFromClient::request_file(Web::FileRequest request)
         handle_file_return(0, IPC::File::adopt_file(file.release_value()), request_id);
 }
 
-ConnectionFromClient::ConnectionFromClient(NonnullOwnPtr<Core::LocalSocket> socket)
+ConnectionFromClient::ConnectionFromClient(IPC::Transport transport)
-    : IPC::ConnectionFromClient<WebWorkerClientEndpoint, WebWorkerServerEndpoint>(*this, move(socket), 1)
+    : IPC::ConnectionFromClient<WebWorkerClientEndpoint, WebWorkerServerEndpoint>(*this, move(transport), 1)
     , m_page_host(PageHost::create(Web::Bindings::main_thread_vm(), *this))
 {
 }

Userland/Services/WebWorker/ConnectionFromClient.h

@@ -36,7 +36,7 @@ public:
     PageHost const& page_host() const { return *m_page_host; }
 
 private:
-    explicit ConnectionFromClient(NonnullOwnPtr<Core::LocalSocket>);
+    explicit ConnectionFromClient(IPC::Transport);
 
     Web::Page& page();
     Web::Page const& page() const;