Everywhere: Transition ImageDecoder to be single-instance, owned by UI

This is the same behavior as RequestServer, with the added benefit that
we know how to gracefully reconnect ImageDecoder to all WebContent
processes on restart.

Ladybird/AppKit/Application/Application.h

@@ -22,6 +22,7 @@ class WebViewBridge;
 - (instancetype)init;
 
 - (ErrorOr<void>)launchRequestServer:(Vector<ByteString> const&)certificates;
+- (ErrorOr<void>)launchImageDecoder;
 - (ErrorOr<NonnullRefPtr<WebView::WebContentClient>>)launchWebContent:(Ladybird::WebViewBridge&)web_view_bridge;
 - (ErrorOr<IPC::File>)launchWebWorker;
 

Ladybird/AppKit/Application/Application.mm

@@ -41,6 +41,11 @@
     return m_application_bridge->launch_request_server(certificates);
 }
 
+- (ErrorOr<void>)launchImageDecoder
+{
+    return m_application_bridge->launch_image_decoder();
+}
+
 - (ErrorOr<NonnullRefPtr<WebView::WebContentClient>>)launchWebContent:(Ladybird::WebViewBridge&)web_view_bridge
 {
     return m_application_bridge->launch_web_content(web_view_bridge);

Ladybird/AppKit/Application/ApplicationBridge.cpp

@@ -9,6 +9,7 @@
 #include <Ladybird/AppKit/UI/LadybirdWebViewBridge.h>
 #include <Ladybird/HelperProcess.h>
 #include <Ladybird/Utilities.h>
+#include <LibImageDecoderClient/Client.h>
 #include <LibProtocol/RequestClient.h>
 #include <LibWebView/WebContentClient.h>
 
@@ -19,6 +20,7 @@ namespace Ladybird {
 // is limited to .cpp files (i.e. not .h files that an Objective-C file can include).
 struct ApplicationBridgeImpl {
     RefPtr<Protocol::RequestClient> request_server_client;
+    RefPtr<ImageDecoderClient::Client> image_decoder_client;
 };
 
 ApplicationBridge::ApplicationBridge()
@@ -37,13 +39,47 @@ ErrorOr<void> ApplicationBridge::launch_request_server(Vector<ByteString> const&
     return {};
 }
 
+static ErrorOr<NonnullRefPtr<ImageDecoderClient::Client>> launch_new_image_decoder()
+{
+    auto image_decoder_paths = TRY(get_paths_for_helper_process("ImageDecoder"sv));
+    return launch_image_decoder_process(image_decoder_paths);
+}
+
+ErrorOr<void> ApplicationBridge::launch_image_decoder()
+{
+    m_impl->image_decoder_client = TRY(launch_new_image_decoder());
+
+    m_impl->image_decoder_client->on_death = [this] {
+        m_impl->image_decoder_client = nullptr;
+        if (auto err = this->launch_image_decoder(); err.is_error()) {
+            dbgln("Failed to restart image decoder: {}", err.error());
+            VERIFY_NOT_REACHED();
+        }
+
+        auto num_clients = WebView::WebContentClient::client_count();
+        auto new_sockets = m_impl->image_decoder_client->send_sync_but_allow_failure<Messages::ImageDecoderServer::ConnectNewClients>(num_clients);
+        if (!new_sockets || new_sockets->sockets().size() == 0) {
+            dbgln("Failed to connect {} new clients to ImageDecoder", num_clients);
+            VERIFY_NOT_REACHED();
+        }
+
+        WebView::WebContentClient::for_each_client([sockets = new_sockets->take_sockets()](WebView::WebContentClient& client) mutable {
+            client.async_connect_to_image_decoder(sockets.take_last());
+            return IterationDecision::Continue;
+        });
+    };
+
+    return {};
+}
+
 ErrorOr<NonnullRefPtr<WebView::WebContentClient>> ApplicationBridge::launch_web_content(WebViewBridge& web_view_bridge)
 {
     // FIXME: Fail to open the tab, rather than crashing the whole application if this fails
     auto request_server_socket = TRY(connect_new_request_server_client(*m_impl->request_server_client));
+    auto image_decoder_socket = TRY(connect_new_image_decoder_client(*m_impl->image_decoder_client));
 
     auto web_content_paths = TRY(get_paths_for_helper_process("WebContent"sv));
-    auto web_content = TRY(launch_web_content_process(web_view_bridge, web_content_paths, web_view_bridge.web_content_options(), move(request_server_socket)));
+    auto web_content = TRY(launch_web_content_process(web_view_bridge, web_content_paths, web_view_bridge.web_content_options(), move(image_decoder_socket), move(request_server_socket)));
 
     return web_content;
 }

Ladybird/AppKit/Application/ApplicationBridge.h

@@ -22,6 +22,7 @@ public:
     ~ApplicationBridge();
 
     ErrorOr<void> launch_request_server(Vector<ByteString> const& certificates);
+    ErrorOr<void> launch_image_decoder();
     ErrorOr<NonnullRefPtr<WebView::WebContentClient>> launch_web_content(WebViewBridge&);
     ErrorOr<IPC::File> launch_web_worker();
 

Ladybird/AppKit/main.mm

@@ -136,6 +136,8 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     // FIXME: Create an abstraction to re-spawn the RequestServer and re-hook up its client hooks to each tab on crash
     TRY([application launchRequestServer:certificates]);
 
+    TRY([application launchImageDecoder]);
+
     StringBuilder command_line_builder;
     command_line_builder.join(' ', arguments.strings);
     Ladybird::WebContentOptions web_content_options {

Ladybird/HelperProcess.cpp

@@ -77,6 +77,7 @@ ErrorOr<NonnullRefPtr<WebView::WebContentClient>> launch_web_content_process(
     WebView::ViewImplementation& view,
     ReadonlySpan<ByteString> candidate_web_content_paths,
     Ladybird::WebContentOptions const& web_content_options,
+    IPC::File image_decoder_socket,
     Optional<IPC::File> request_server_socket)
 {
     Vector<ByteString> arguments {
@@ -113,6 +114,9 @@ ErrorOr<NonnullRefPtr<WebView::WebContentClient>> launch_web_content_process(
         arguments.append(ByteString::number(request_server_socket->fd()));
     }
 
+    arguments.append("--image-decoder-socket"sv);
+    arguments.append(ByteString::number(image_decoder_socket.fd()));
+
     return launch_server_process<WebView::WebContentClient>("WebContent"sv, candidate_web_content_paths, move(arguments), RegisterWithProcessManager::No, web_content_options.enable_callgrind_profiling, view);
 }
 
@@ -164,3 +168,19 @@ ErrorOr<IPC::File> connect_new_request_server_client(Protocol::RequestClient& cl
 
     return socket;
 }
+
+ErrorOr<IPC::File> connect_new_image_decoder_client(ImageDecoderClient::Client& client)
+{
+    auto new_socket = client.send_sync_but_allow_failure<Messages::ImageDecoderServer::ConnectNewClients>(1);
+    if (!new_socket)
+        return Error::from_string_literal("Failed to connect to ImageDecoder");
+
+    auto sockets = new_socket->take_sockets();
+    if (sockets.size() != 1)
+        return Error::from_string_literal("Failed to connect to ImageDecoder");
+
+    auto socket = sockets.take_last();
+    TRY(socket.clear_close_on_exec());
+
+    return socket;
+}

Ladybird/HelperProcess.h

@@ -21,6 +21,7 @@ ErrorOr<NonnullRefPtr<WebView::WebContentClient>> launch_web_content_process(
     WebView::ViewImplementation& view,
     ReadonlySpan<ByteString> candidate_web_content_paths,
     Ladybird::WebContentOptions const&,
+    IPC::File image_decoder_socket,
     Optional<IPC::File> request_server_socket = {});
 
 ErrorOr<NonnullRefPtr<ImageDecoderClient::Client>> launch_image_decoder_process(ReadonlySpan<ByteString> candidate_image_decoder_paths);
@@ -28,3 +29,4 @@ ErrorOr<NonnullRefPtr<Web::HTML::WebWorkerClient>> launch_web_worker_process(Rea
 ErrorOr<NonnullRefPtr<Protocol::RequestClient>> launch_request_server_process(ReadonlySpan<ByteString> candidate_request_server_paths, StringView serenity_resource_root, Vector<ByteString> const& certificates);
 
 ErrorOr<IPC::File> connect_new_request_server_client(Protocol::RequestClient&);
+ErrorOr<IPC::File> connect_new_image_decoder_client(ImageDecoderClient::Client&);

Ladybird/ImageCodecPlugin.cpp

@@ -6,11 +6,6 @@
  */
 
 #include "ImageCodecPlugin.h"
-#ifdef AK_OS_ANDROID
-#    include <Ladybird/Android/src/main/cpp/WebContentService.h>
-#else
-#    include "HelperProcess.h"
-#endif
 #include "Utilities.h"
 #include <LibGfx/Bitmap.h>
 #include <LibGfx/ImageFormats/ImageDecoder.h>
@@ -18,28 +13,37 @@
 
 namespace Ladybird {
 
-ImageCodecPlugin::~ImageCodecPlugin() = default;
-
-NonnullRefPtr<Core::Promise<Web::Platform::DecodedImage>> ImageCodecPlugin::decode_image(ReadonlyBytes bytes, Function<ErrorOr<void>(Web::Platform::DecodedImage&)> on_resolved, Function<void(Error&)> on_rejected)
+ImageCodecPlugin::ImageCodecPlugin(NonnullRefPtr<ImageDecoderClient::Client> client)
+    : m_client(move(client))
 {
-    if (!m_client) {
-#ifdef AK_OS_ANDROID
-        m_client = MUST(bind_service<ImageDecoderClient::Client>(&bind_image_decoder_java));
-#else
-        auto candidate_image_decoder_paths = get_paths_for_helper_process("ImageDecoder"sv).release_value_but_fixme_should_propagate_errors();
-        m_client = launch_image_decoder_process(candidate_image_decoder_paths).release_value_but_fixme_should_propagate_errors();
-#endif
-        m_client->on_death = [&] {
+    m_client->on_death = [this] {
         m_client = nullptr;
     };
 }
 
+void ImageCodecPlugin::set_client(NonnullRefPtr<ImageDecoderClient::Client> client)
+{
+    m_client = move(client);
+    m_client->on_death = [this] {
+        m_client = nullptr;
+    };
+}
+
+ImageCodecPlugin::~ImageCodecPlugin() = default;
+
+NonnullRefPtr<Core::Promise<Web::Platform::DecodedImage>> ImageCodecPlugin::decode_image(ReadonlyBytes bytes, Function<ErrorOr<void>(Web::Platform::DecodedImage&)> on_resolved, Function<void(Error&)> on_rejected)
+{
     auto promise = Core::Promise<Web::Platform::DecodedImage>::construct();
     if (on_resolved)
         promise->on_resolution = move(on_resolved);
     if (on_rejected)
         promise->on_rejection = move(on_rejected);
 
+    if (!m_client) {
+        promise->reject(Error::from_string_literal("ImageDecoderClient is disconnected"));
+        return promise;
+    }
+
     auto image_decoder_promise = m_client->decode_image(
         bytes,
         [promise](ImageDecoderClient::DecodedImage& result) -> ErrorOr<void> {

Ladybird/ImageCodecPlugin.h

@@ -14,11 +14,13 @@ namespace Ladybird {
 
 class ImageCodecPlugin final : public Web::Platform::ImageCodecPlugin {
 public:
-    ImageCodecPlugin() = default;
+    explicit ImageCodecPlugin(NonnullRefPtr<ImageDecoderClient::Client>);
     virtual ~ImageCodecPlugin() override;
 
     virtual NonnullRefPtr<Core::Promise<Web::Platform::DecodedImage>> decode_image(ReadonlyBytes, Function<ErrorOr<void>(Web::Platform::DecodedImage&)> on_resolved, Function<void(Error&)> on_rejected) override;
 
+    void set_client(NonnullRefPtr<ImageDecoderClient::Client>);
+
 private:
     RefPtr<ImageDecoderClient::Client> m_client;
 };

Ladybird/Qt/Application.cpp

@@ -7,6 +7,8 @@
 #include "Application.h"
 #include "StringUtils.h"
 #include "TaskManagerWindow.h"
+#include <Ladybird/HelperProcess.h>
+#include <Ladybird/Utilities.h>
 #include <LibWebView/URL.h>
 #include <QFileOpenEvent>
 
@@ -43,6 +45,38 @@ bool Application::event(QEvent* event)
     return QApplication::event(event);
 }
 
+static ErrorOr<NonnullRefPtr<ImageDecoderClient::Client>> launch_new_image_decoder()
+{
+    auto paths = TRY(get_paths_for_helper_process("ImageDecoder"sv));
+    return launch_image_decoder_process(paths);
+}
+
+ErrorOr<void> Application::initialize_image_decoder()
+{
+    m_image_decoder_client = TRY(launch_new_image_decoder());
+
+    m_image_decoder_client->on_death = [this] {
+        m_image_decoder_client = nullptr;
+        if (auto err = this->initialize_image_decoder(); err.is_error()) {
+            dbgln("Failed to restart image decoder: {}", err.error());
+            VERIFY_NOT_REACHED();
+        }
+
+        auto num_clients = WebView::WebContentClient::client_count();
+        auto new_sockets = m_image_decoder_client->send_sync_but_allow_failure<Messages::ImageDecoderServer::ConnectNewClients>(num_clients);
+        if (!new_sockets || new_sockets->sockets().size() == 0) {
+            dbgln("Failed to connect {} new clients to ImageDecoder", num_clients);
+            VERIFY_NOT_REACHED();
+        }
+
+        WebView::WebContentClient::for_each_client([sockets = new_sockets->take_sockets()](WebView::WebContentClient& client) mutable {
+            client.async_connect_to_image_decoder(sockets.take_last());
+            return IterationDecision::Continue;
+        });
+    };
+    return {};
+}
+
 void Application::show_task_manager_window()
 {
     if (!m_task_manager_window) {

Ladybird/Qt/Application.h

@@ -9,6 +9,7 @@
 #include <AK/Function.h>
 #include <AK/HashTable.h>
 #include <Ladybird/Qt/BrowserWindow.h>
+#include <LibImageDecoderClient/Client.h>
 #include <LibProtocol/RequestClient.h>
 #include <LibURL/URL.h>
 #include <QApplication>
@@ -27,6 +28,9 @@ public:
     Function<void(URL::URL)> on_open_file;
     RefPtr<Protocol::RequestClient> request_server_client;
 
+    NonnullRefPtr<ImageDecoderClient::Client> image_decoder_client() const { return *m_image_decoder_client; }
+    ErrorOr<void> initialize_image_decoder();
+
     BrowserWindow& new_window(Vector<URL::URL> const& initial_urls, WebView::CookieJar&, WebContentOptions const&, StringView webdriver_content_ipc_path, bool allow_popups, Tab* parent_tab = nullptr, Optional<u64> page_index = {});
 
     void show_task_manager_window();
@@ -38,6 +42,8 @@ public:
 private:
     TaskManagerWindow* m_task_manager_window { nullptr };
     BrowserWindow* m_active_window { nullptr };
+
+    RefPtr<ImageDecoderClient::Client> m_image_decoder_client;
 };
 
 }

Ladybird/Qt/WebContentView.cpp

@@ -549,8 +549,11 @@ void WebContentView::initialize_client(WebView::ViewImplementation::CreateNewCli
             request_server_socket = AK::move(socket);
         }
 
+        auto image_decoder = static_cast<Ladybird::Application*>(QApplication::instance())->image_decoder_client();
+        auto image_decoder_socket = connect_new_image_decoder_client(*image_decoder).release_value_but_fixme_should_propagate_errors();
+
         auto candidate_web_content_paths = get_paths_for_helper_process("WebContent"sv).release_value_but_fixme_should_propagate_errors();
-        auto new_client = launch_web_content_process(*this, candidate_web_content_paths, m_web_content_options, AK::move(request_server_socket)).release_value_but_fixme_should_propagate_errors();
+        auto new_client = launch_web_content_process(*this, candidate_web_content_paths, m_web_content_options, AK::move(image_decoder_socket), AK::move(request_server_socket)).release_value_but_fixme_should_propagate_errors();
 
         m_client_state.client = new_client;
     } else {

Ladybird/Qt/main.cpp

@@ -166,7 +166,9 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     // FIXME: Create an abstraction to re-spawn the RequestServer and re-hook up its client hooks to each tab on crash
     auto request_server_paths = TRY(get_paths_for_helper_process("RequestServer"sv));
     auto protocol_client = TRY(launch_request_server_process(request_server_paths, s_serenity_resource_root, certificates));
-    app.request_server_client = protocol_client;
+    app.request_server_client = move(protocol_client);
+
+    TRY(app.initialize_image_decoder());
 
     StringBuilder command_line_builder;
     command_line_builder.join(' ', arguments.strings);

Ladybird/WebContent/main.cpp

@@ -14,7 +14,6 @@
 #include <LibCore/LocalServer.h>
 #include <LibCore/Process.h>
 #include <LibCore/Resource.h>
-#include <LibCore/System.h>
 #include <LibCore/SystemServerTakeover.h>
 #include <LibIPC/ConnectionFromClient.h>
 #include <LibJS/Bytecode/Interpreter.h>
@@ -28,9 +27,7 @@
 #include <LibWeb/PermissionsPolicy/AutoplayAllowlist.h>
 #include <LibWeb/Platform/AudioCodecPluginAgnostic.h>
 #include <LibWeb/Platform/EventLoopPluginSerenity.h>
-#include <LibWeb/WebSockets/WebSocket.h>
 #include <LibWebView/RequestServerAdapter.h>
-#include <LibWebView/WebSocketClientAdapter.h>
 #include <WebContent/ConnectionFromClient.h>
 #include <WebContent/PageClient.h>
 #include <WebContent/WebDriverConnection.h>
@@ -52,6 +49,8 @@
 static ErrorOr<void> load_content_filters();
 static ErrorOr<void> load_autoplay_allowlist();
 static ErrorOr<void> initialize_lagom_networking(int request_server_socket);
+static ErrorOr<void> initialize_image_decoder(int image_decoder_socket);
+static ErrorOr<void> reinitialize_image_decoder(IPC::File const& image_decoder_socket);
 
 namespace JS {
 extern bool g_log_all_js_exceptions;
@@ -79,7 +78,6 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     platform_init();
 
     Web::Platform::EventLoopPlugin::install(*new Web::Platform::EventLoopPluginSerenity);
-    Web::Platform::ImageCodecPlugin::install(*new Ladybird::ImageCodecPlugin);
 
     Web::Platform::AudioCodecPlugin::install_creation_hook([](auto loader) {
 #if defined(HAVE_QT_MULTIMEDIA)
@@ -97,6 +95,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     StringView mach_server_name {};
     Vector<ByteString> certificates;
     int request_server_socket { -1 };
+    int image_decoder_socket { -1 };
     bool is_layout_test_mode = false;
     bool expose_internals_object = false;
     bool use_lagom_networking = false;
@@ -111,6 +110,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     args_parser.add_option(command_line, "Chrome process command line", "command-line", 0, "command_line");
     args_parser.add_option(executable_path, "Chrome process executable path", "executable-path", 0, "executable_path");
     args_parser.add_option(request_server_socket, "File descriptor of the socket for the RequestServer connection", "request-server-socket", 'r', "request_server_socket");
+    args_parser.add_option(image_decoder_socket, "File descriptor of the socket for the ImageDecoder connection", "image-decoder-socket", 'i', "image_decoder_socket");
     args_parser.add_option(is_layout_test_mode, "Is layout test mode", "layout-test-mode");
     args_parser.add_option(expose_internals_object, "Expose internals object", "expose-internals-object");
     args_parser.add_option(use_lagom_networking, "Enable Lagom servers for networking", "use-lagom-networking");
@@ -160,6 +160,8 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
 #endif
         TRY(initialize_lagom_networking(request_server_socket));
 
+    TRY(initialize_image_decoder(image_decoder_socket));
+
     Web::HTML::Window::set_internals_object_exposed(expose_internals_object);
 
     Web::Platform::FontPlugin::install(*new Ladybird::FontPlugin(is_layout_test_mode));
@@ -185,6 +187,12 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     auto webcontent_socket = TRY(Core::take_over_socket_from_system_server("WebContent"sv));
     auto webcontent_client = TRY(WebContent::ConnectionFromClient::try_create(move(webcontent_socket)));
 
+    webcontent_client->on_image_decoder_connection = [&](auto& socket_file) {
+        auto maybe_error = reinitialize_image_decoder(socket_file);
+        if (maybe_error.is_error())
+            dbgln("Failed to reinitialize image decoder: {}", maybe_error.error());
+    };
+
     return event_loop.exec();
 }
 
@@ -246,3 +254,27 @@ ErrorOr<void> initialize_lagom_networking(int request_server_socket)
     Web::ResourceLoader::initialize(TRY(WebView::RequestServerAdapter::try_create(move(new_client))));
     return {};
 }
+
+ErrorOr<void> initialize_image_decoder(int image_decoder_socket)
+{
+    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)));
+
+    Web::Platform::ImageCodecPlugin::install(*new Ladybird::ImageCodecPlugin(move(new_client)));
+
+    return {};
+}
+
+ErrorOr<void> reinitialize_image_decoder(IPC::File const& image_decoder_socket)
+{
+    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)));
+
+    static_cast<Ladybird::ImageCodecPlugin&>(Web::Platform::ImageCodecPlugin::the()).set_client(move(new_client));
+
+    return {};
+}

Userland/Services/ImageDecoder/ConnectionFromClient.cpp

@@ -5,6 +5,7 @@
  */
 
 #include <AK/Debug.h>
+#include <AK/IDAllocator.h>
 #include <ImageDecoder/ConnectionFromClient.h>
 #include <ImageDecoder/ImageDecoderClientEndpoint.h>
 #include <LibGfx/Bitmap.h>
@@ -13,9 +14,13 @@
 
 namespace ImageDecoder {
 
+static HashMap<int, RefPtr<ConnectionFromClient>> s_connections;
+static IDAllocator s_client_ids;
+
 ConnectionFromClient::ConnectionFromClient(NonnullOwnPtr<Core::LocalSocket> socket)
-    : IPC::ConnectionFromClient<ImageDecoderClientEndpoint, ImageDecoderServerEndpoint>(*this, move(socket), 1)
+    : IPC::ConnectionFromClient<ImageDecoderClientEndpoint, ImageDecoderServerEndpoint>(*this, move(socket), s_client_ids.allocate())
 {
+    s_connections.set(client_id(), *this);
 }
 
 void ConnectionFromClient::die()
@@ -25,9 +30,50 @@ void ConnectionFromClient::die()
     }
     m_pending_jobs.clear();
 
+    auto client_id = this->client_id();
+    s_connections.remove(client_id);
+    s_client_ids.deallocate(client_id);
+
+    if (s_connections.is_empty()) {
         Threading::quit_background_thread();
         Core::EventLoop::current().quit(0);
     }
+}
+
+ErrorOr<IPC::File> ConnectionFromClient::connect_new_client()
+{
+    int socket_fds[2] {};
+    if (auto err = Core::System::socketpair(AF_LOCAL, SOCK_STREAM, 0, socket_fds); err.is_error())
+        return err.release_error();
+
+    auto client_socket_or_error = Core::LocalSocket::adopt_fd(socket_fds[0]);
+    if (client_socket_or_error.is_error()) {
+        close(socket_fds[0]);
+        close(socket_fds[1]);
+        return client_socket_or_error.release_error();
+    }
+
+    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)));
+
+    return IPC::File::adopt_fd(socket_fds[1]);
+}
+
+Messages::ImageDecoderServer::ConnectNewClientsResponse ConnectionFromClient::connect_new_clients(size_t count)
+{
+    Vector<IPC::File> files;
+    files.ensure_capacity(count);
+    for (size_t i = 0; i < count; ++i) {
+        auto file_or_error = connect_new_client();
+        if (file_or_error.is_error()) {
+            dbgln("Failed to connect new client: {}", file_or_error.error());
+            return Vector<IPC::File> {};
+        }
+        files.unchecked_append(file_or_error.release_value());
+    }
+    return files;
+}
 
 static void decode_image_to_bitmaps_and_durations_with_decoder(Gfx::ImageDecoder const& decoder, Optional<Gfx::IntSize> ideal_size, Vector<Gfx::ShareableBitmap>& bitmaps, Vector<u32>& durations)
 {

Userland/Services/ImageDecoder/ConnectionFromClient.h

@@ -39,6 +39,9 @@ private:
 
     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;
+    virtual Messages::ImageDecoderServer::ConnectNewClientsResponse connect_new_clients(size_t count) override;
+
+    ErrorOr<IPC::File> connect_new_client();
 
     NonnullRefPtr<Job> make_decode_image_job(i64 image_id, Core::AnonymousBuffer, Optional<Gfx::IntSize> ideal_size, Optional<ByteString> mime_type);
 

Userland/Services/ImageDecoder/ImageDecoderServer.ipc

@@ -4,4 +4,6 @@ endpoint ImageDecoderServer
 {
     decode_image(Core::AnonymousBuffer data, Optional<Gfx::IntSize> ideal_size, Optional<ByteString> mime_type) => (i64 image_id)
     cancel_decoding(i64 image_id) =|
+
+    connect_new_clients(size_t count) => (Vector<IPC::File> sockets)
 }

Userland/Services/WebContent/ConnectionFromClient.cpp

@@ -104,6 +104,12 @@ void ConnectionFromClient::connect_to_webdriver(u64 page_id, ByteString const& w
     }
 }
 
+void ConnectionFromClient::connect_to_image_decoder(IPC::File const& image_decoder_socket)
+{
+    if (on_image_decoder_connection)
+        on_image_decoder_connection(image_decoder_socket);
+}
+
 void ConnectionFromClient::update_system_theme(u64 page_id, Core::AnonymousBuffer const& theme_buffer)
 {
     auto page = this->page(page_id);

Userland/Services/WebContent/ConnectionFromClient.h

@@ -45,6 +45,8 @@ public:
     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>);
 
@@ -54,6 +56,7 @@ private:
     virtual Messages::WebContentServer::GetWindowHandleResponse get_window_handle(u64 page_id) override;
     virtual void set_window_handle(u64 page_id, String const& handle) override;
     virtual void connect_to_webdriver(u64 page_id, ByteString const& webdriver_ipc_path) override;
+    virtual void connect_to_image_decoder(IPC::File const& image_decoder_socket) override;
     virtual void update_system_theme(u64 page_id, Core::AnonymousBuffer const&) override;
     virtual void update_screen_rects(u64 page_id, Vector<Web::DevicePixelRect> const&, u32) override;
     virtual void load_url(u64 page_id, URL::URL const&) override;

Userland/Services/WebContent/WebContentServer.ipc

@@ -17,6 +17,7 @@ endpoint WebContentServer
     set_window_handle(u64 page_id, String handle) =|
 
     connect_to_webdriver(u64 page_id, ByteString webdriver_ipc_path) =|
+    connect_to_image_decoder(IPC::File socket_fd) =|
 
     update_system_theme(u64 page_id, Core::AnonymousBuffer theme_buffer) =|
     update_screen_rects(u64 page_id, Vector<Web::DevicePixelRect> rects, u32 main_screen_index) =|

Userland/Utilities/headless-browser.cpp

@@ -43,6 +43,7 @@
 #include <LibGfx/StandardCursor.h>
 #include <LibGfx/SystemTheme.h>
 #include <LibIPC/File.h>
+#include <LibImageDecoderClient/Client.h>
 #include <LibProtocol/RequestClient.h>
 #include <LibURL/URL.h>
 #include <LibWeb/Cookie/Cookie.h>
@@ -65,14 +66,18 @@ public:
     static ErrorOr<NonnullOwnPtr<HeadlessWebContentView>> create(Core::AnonymousBuffer theme, Gfx::IntSize const& window_size, String const& command_line, StringView web_driver_ipc_path, Ladybird::IsLayoutTestMode is_layout_test_mode = Ladybird::IsLayoutTestMode::No, Vector<ByteString> const& certificates = {}, StringView resources_folder = {})
     {
         RefPtr<Protocol::RequestClient> request_client;
+        RefPtr<ImageDecoderClient::Client> image_decoder_client;
 
         auto request_server_paths = TRY(get_paths_for_helper_process("RequestServer"sv));
         request_client = TRY(launch_request_server_process(request_server_paths, resources_folder, certificates));
 
+        auto image_decoder_paths = TRY(get_paths_for_helper_process("ImageDecoder"sv));
+        image_decoder_client = TRY(launch_image_decoder_process(image_decoder_paths));
+
         auto database = TRY(WebView::Database::create());
         auto cookie_jar = TRY(WebView::CookieJar::create(*database));
 
-        auto view = TRY(adopt_nonnull_own_or_enomem(new (nothrow) HeadlessWebContentView(move(database), move(cookie_jar), request_client)));
+        auto view = TRY(adopt_nonnull_own_or_enomem(new (nothrow) HeadlessWebContentView(move(database), move(cookie_jar), image_decoder_client, request_client)));
 
         Ladybird::WebContentOptions web_content_options {
             .command_line = command_line,
@@ -81,9 +86,10 @@ public:
         };
 
         auto request_server_socket = TRY(connect_new_request_server_client(*request_client));
+        auto image_decoder_socket = TRY(connect_new_image_decoder_client(*image_decoder_client));
 
         auto candidate_web_content_paths = TRY(get_paths_for_helper_process("WebContent"sv));
-        view->m_client_state.client = TRY(launch_web_content_process(*view, candidate_web_content_paths, web_content_options, move(request_server_socket)));
+        view->m_client_state.client = TRY(launch_web_content_process(*view, candidate_web_content_paths, web_content_options, move(image_decoder_socket), move(request_server_socket)));
 
         view->client().async_update_system_theme(0, move(theme));
 
@@ -145,10 +151,11 @@ public:
     }
 
 private:
-    HeadlessWebContentView(NonnullRefPtr<WebView::Database> database, NonnullOwnPtr<WebView::CookieJar> cookie_jar, RefPtr<Protocol::RequestClient> request_client = nullptr)
+    HeadlessWebContentView(NonnullRefPtr<WebView::Database> database, NonnullOwnPtr<WebView::CookieJar> cookie_jar, RefPtr<ImageDecoderClient::Client> image_decoder_client, RefPtr<Protocol::RequestClient> request_client)
         : m_database(move(database))
         , m_cookie_jar(move(cookie_jar))
         , m_request_client(move(request_client))
+        , m_image_decoder_client(move(image_decoder_client))
     {
         on_get_cookie = [this](auto const& url, auto source) {
             return m_cookie_jar->get_cookie(url, source);
@@ -178,6 +185,7 @@ private:
     NonnullRefPtr<WebView::Database> m_database;
     NonnullOwnPtr<WebView::CookieJar> m_cookie_jar;
     RefPtr<Protocol::RequestClient> m_request_client;
+    RefPtr<ImageDecoderClient::Client> m_image_decoder_client;
 };
 
 static ErrorOr<NonnullRefPtr<Core::Timer>> load_page_for_screenshot_and_exit(Core::EventLoop& event_loop, HeadlessWebContentView& view, URL::URL url, int screenshot_timeout)