LibGUI+WindowServer: Separate window manager IPC from regular IPC

With this patch the window manager related functionality is split out
onto a new endpoint pair named WindowManagerServer/Client.  This allows
window manager functionality to be potentially privilege separated in
the future.  To this end, a new client named WMConnectionClient
is used to maintain a window manager connection.  When a process
connects to the endpoint and greets the WindowServer as a window manager
(via Window::make_window_manager(int)), they're subscribed to the events
they requested via the WM event mask.

This patch also removes the hardcoding of the Taskbar WindowType to
receive WM events automatically.  However, being a window manager still
requires having an active window, at the moment.

Userland/Libraries/LibGUI/CMakeLists.txt

@@ -96,6 +96,7 @@ set(SOURCES
     Widget.cpp
     Window.cpp
     WindowServerConnection.cpp
+    WindowManagerServerConnection.cpp
     Wizards/WizardDialog.cpp
     Wizards/AbstractWizardPage.cpp
     Wizards/CoverWizardPage.cpp

Userland/Libraries/LibGUI/Window.cpp

@@ -39,6 +39,7 @@
 #include <LibGUI/Painter.h>
 #include <LibGUI/Widget.h>
 #include <LibGUI/Window.h>
+#include <LibGUI/WindowManagerServerConnection.h>
 #include <LibGUI/WindowServerConnection.h>
 #include <LibGfx/Bitmap.h>
 #include <fcntl.h>
@@ -315,6 +316,14 @@ void Window::set_window_type(WindowType window_type)
     }
 }
 
+void Window::make_window_manager(unsigned event_mask)
+{
+    GUI::WindowManagerServerConnection::the()
+        .post_message(Messages::WindowManagerServer::SetEventMask(event_mask));
+    GUI::WindowManagerServerConnection::the()
+        .post_message(Messages::WindowManagerServer::SetManagerWindow(m_window_id));
+}
+
 void Window::set_cursor(Gfx::StandardCursor cursor)
 {
     if (m_cursor == cursor)

Userland/Libraries/LibGUI/Window.h

@@ -80,6 +80,8 @@ public:
 
     int window_id() const { return m_window_id; }
 
+    void make_window_manager(unsigned event_mask);
+
     String title() const;
     void set_title(String);
 

Userland/Libraries/LibGUI/WindowManagerServerConnection.cpp

@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2021, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <LibGUI/Event.h>
+#include <LibGUI/Window.h>
+#include <LibGUI/WindowManagerServerConnection.h>
+#include <WindowServer/Window.h>
+
+namespace GUI {
+
+WindowManagerServerConnection& WindowManagerServerConnection::the()
+{
+    static WindowManagerServerConnection* s_connection = nullptr;
+    if (!s_connection)
+        s_connection = new WindowManagerServerConnection;
+    return *s_connection;
+}
+
+void WindowManagerServerConnection::handshake()
+{
+    // :^)
+}
+
+void WindowManagerServerConnection::handle(const Messages::WindowManagerClient::WindowStateChanged& message)
+{
+    if (auto* window = Window::from_window_id(message.wm_id()))
+        Core::EventLoop::current().post_event(*window, make<WMWindowStateChangedEvent>(message.client_id(), message.window_id(), message.parent_client_id(), message.parent_window_id(), message.title(), message.rect(), message.is_active(), message.is_modal(), static_cast<WindowType>(message.window_type()), message.is_minimized(), message.is_frameless(), message.progress()));
+}
+
+void WindowManagerServerConnection::handle(const Messages::WindowManagerClient::AppletAreaSizeChanged& message)
+{
+    if (auto* window = Window::from_window_id(message.wm_id()))
+        Core::EventLoop::current().post_event(*window, make<WMAppletAreaSizeChangedEvent>(message.size()));
+}
+
+void WindowManagerServerConnection::handle(const Messages::WindowManagerClient::WindowRectChanged& message)
+{
+    if (auto* window = Window::from_window_id(message.wm_id()))
+        Core::EventLoop::current().post_event(*window, make<WMWindowRectChangedEvent>(message.client_id(), message.window_id(), message.rect()));
+}
+
+void WindowManagerServerConnection::handle(const Messages::WindowManagerClient::WindowIconBitmapChanged& message)
+{
+    if (auto* window = Window::from_window_id(message.wm_id())) {
+        Core::EventLoop::current().post_event(*window, make<WMWindowIconBitmapChangedEvent>(message.client_id(), message.window_id(), message.bitmap().bitmap()));
+    }
+}
+
+void WindowManagerServerConnection::handle(const Messages::WindowManagerClient::WindowRemoved& message)
+{
+    if (auto* window = Window::from_window_id(message.wm_id()))
+        Core::EventLoop::current().post_event(*window, make<WMWindowRemovedEvent>(message.client_id(), message.window_id()));
+}
+}

Userland/Libraries/LibGUI/WindowManagerServerConnection.h

@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2021, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <LibIPC/ServerConnection.h>
+#include <WindowServer/WindowManagerClientEndpoint.h>
+#include <WindowServer/WindowManagerServerEndpoint.h>
+
+namespace GUI {
+
+class WindowManagerServerConnection
+    : public IPC::ServerConnection<WindowManagerClientEndpoint, WindowManagerServerEndpoint>
+    , public WindowManagerClientEndpoint {
+    C_OBJECT(WindowManagerServerConnection)
+public:
+    WindowManagerServerConnection()
+        : IPC::ServerConnection<WindowManagerClientEndpoint, WindowManagerServerEndpoint>(*this, "/tmp/portal/wm")
+    {
+        handshake();
+    }
+
+    virtual void handshake() override;
+    static WindowManagerServerConnection& the();
+
+private:
+    virtual void handle(const Messages::WindowManagerClient::WindowRemoved&) override;
+    virtual void handle(const Messages::WindowManagerClient::WindowStateChanged&) override;
+    virtual void handle(const Messages::WindowManagerClient::WindowIconBitmapChanged&) override;
+    virtual void handle(const Messages::WindowManagerClient::WindowRectChanged&) override;
+    virtual void handle(const Messages::WindowManagerClient::AppletAreaSizeChanged&) override;
+};
+
+}

Userland/Libraries/LibGUI/WindowServerConnection.cpp

@@ -273,37 +273,6 @@ void WindowServerConnection::handle(const Messages::WindowClient::MenuItemActiva
         action->activate(menu);
 }
 
-void WindowServerConnection::handle(const Messages::WindowClient::WM_WindowStateChanged& message)
-{
-    if (auto* window = Window::from_window_id(message.wm_id()))
-        Core::EventLoop::current().post_event(*window, make<WMWindowStateChangedEvent>(message.client_id(), message.window_id(), message.parent_client_id(), message.parent_window_id(), message.title(), message.rect(), message.is_active(), message.is_modal(), static_cast<WindowType>(message.window_type()), message.is_minimized(), message.is_frameless(), message.progress()));
-}
-
-void WindowServerConnection::handle(const Messages::WindowClient::WM_AppletAreaSizeChanged& message)
-{
-    if (auto* window = Window::from_window_id(message.wm_id()))
-        Core::EventLoop::current().post_event(*window, make<WMAppletAreaSizeChangedEvent>(message.size()));
-}
-
-void WindowServerConnection::handle(const Messages::WindowClient::WM_WindowRectChanged& message)
-{
-    if (auto* window = Window::from_window_id(message.wm_id()))
-        Core::EventLoop::current().post_event(*window, make<WMWindowRectChangedEvent>(message.client_id(), message.window_id(), message.rect()));
-}
-
-void WindowServerConnection::handle(const Messages::WindowClient::WM_WindowIconBitmapChanged& message)
-{
-    if (auto* window = Window::from_window_id(message.wm_id())) {
-        Core::EventLoop::current().post_event(*window, make<WMWindowIconBitmapChangedEvent>(message.client_id(), message.window_id(), message.bitmap().bitmap()));
-    }
-}
-
-void WindowServerConnection::handle(const Messages::WindowClient::WM_WindowRemoved& message)
-{
-    if (auto* window = Window::from_window_id(message.wm_id()))
-        Core::EventLoop::current().post_event(*window, make<WMWindowRemovedEvent>(message.client_id(), message.window_id()));
-}
-
 void WindowServerConnection::handle(const Messages::WindowClient::ScreenRectChanged& message)
 {
     Desktop::the().did_receive_screen_rect({}, message.rect());

Userland/Libraries/LibGUI/WindowServerConnection.h

@@ -66,11 +66,6 @@ private:
     virtual void handle(const Messages::WindowClient::MenuItemActivated&) override;
     virtual void handle(const Messages::WindowClient::MenuVisibilityDidChange&) override;
     virtual void handle(const Messages::WindowClient::ScreenRectChanged&) override;
-    virtual void handle(const Messages::WindowClient::WM_WindowRemoved&) override;
-    virtual void handle(const Messages::WindowClient::WM_WindowStateChanged&) override;
-    virtual void handle(const Messages::WindowClient::WM_WindowIconBitmapChanged&) override;
-    virtual void handle(const Messages::WindowClient::WM_WindowRectChanged&) override;
-    virtual void handle(const Messages::WindowClient::WM_AppletAreaSizeChanged&) override;
     virtual void handle(const Messages::WindowClient::AsyncSetWallpaperFinished&) override;
     virtual void handle(const Messages::WindowClient::DragDropped&) override;
     virtual void handle(const Messages::WindowClient::DragAccepted&) override;