Consolidate all xcb functionality into one subdirectory

The Linux platform has multiple windowing systems. Support for xcb is
currently in progress, support for Wayland is planned in the future. The
way the current xcb support is included is by making some file with a
`_xcb` suffix, and placing `#if PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB` around
most of that file's contents.

With this change, all of the code in AzFramework that uses xcb directly is
inside the `Platform/Common/Xcb` subdirectory. It greatly reduces the
amount of code in compile-time `#ifdef` checks for the chosen windowing
system. It also provides a logical place to include O3DE-specific xcb
C++ wrappers and interfaces, without polluting non-xcb related code.

Signed-off-by: Chris Burel <burelc@amazon.com>

Code/Editor/Core/QtEditorApplication_linux.cpp

@@ -9,7 +9,7 @@
 #include "QtEditorApplication.h"
 
 #ifdef PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB
-#include <AzFramework/API/ApplicationAPI_Linux.h>
+#include <AzFramework/XcbEventHandler.h>
 #endif
 
 namespace Editor
@@ -19,7 +19,7 @@ namespace Editor
         if (GetIEditor()->IsInGameMode())
         {
 #ifdef PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB
-            AzFramework::LinuxXcbEventHandlerBus::Broadcast(&AzFramework::LinuxXcbEventHandler::HandleXcbEvent, static_cast<xcb_generic_event_t*>(message));
+            AzFramework::XcbEventHandlerBus::Broadcast(&AzFramework::XcbEventHandler::HandleXcbEvent, static_cast<xcb_generic_event_t*>(message));
 #endif
             return true;
         }

Code/Framework/AzFramework/Platform/Common/Xcb/AzFramework/XcbApplication.cpp

@@ -6,29 +6,26 @@
  *
  */
 
-#include <AzFramework/API/ApplicationAPI_Platform.h>
+#include <AzFramework/XcbApplication.h>
-#include <AzFramework/Application/Application.h>
+#include <AzFramework/XcbEventHandler.h>
-#include "Application_Linux_xcb.h"
 
-////////////////////////////////////////////////////////////////////////////////////////////////////
 namespace AzFramework
 {
-#if PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB
     ////////////////////////////////////////////////////////////////////////////////////////////////
-    class LinuxXcbConnectionManagerImpl
+    class XcbConnectionManagerImpl
-        : public LinuxXcbConnectionManagerBus::Handler
+        : public XcbConnectionManagerBus::Handler
     {
     public:
-        LinuxXcbConnectionManagerImpl()
+        XcbConnectionManagerImpl()
         {
             m_xcbConnection = xcb_connect(nullptr, nullptr);
-            AZ_Error("ApplicationLinux", m_xcbConnection != nullptr, "Unable to connect to X11 Server.");
+            AZ_Error("Application", m_xcbConnection != nullptr, "Unable to connect to X11 Server.");
-            LinuxXcbConnectionManagerBus::Handler::BusConnect();
+            XcbConnectionManagerBus::Handler::BusConnect();
         }
 
-        ~LinuxXcbConnectionManagerImpl()
+        ~XcbConnectionManagerImpl() override
         {
-            LinuxXcbConnectionManagerBus::Handler::BusDisconnect();
+            XcbConnectionManagerBus::Handler::BusDisconnect();
             xcb_disconnect(m_xcbConnection);   
         }
 
@@ -42,53 +39,51 @@ namespace AzFramework
     };
 
     ////////////////////////////////////////////////////////////////////////////////////////////////
-    ApplicationLinux_xcb::ApplicationLinux_xcb()
+    XcbApplication::XcbApplication()
     {
         LinuxLifecycleEvents::Bus::Handler::BusConnect();
-        m_xcbConnectionManager = AZStd::make_unique<LinuxXcbConnectionManagerImpl>();
+        m_xcbConnectionManager = AZStd::make_unique<XcbConnectionManagerImpl>();
-        if (LinuxXcbConnectionManagerInterface::Get() == nullptr)
+        if (XcbConnectionManagerInterface::Get() == nullptr)
         {
-            LinuxXcbConnectionManagerInterface::Register(m_xcbConnectionManager.get());
+            XcbConnectionManagerInterface::Register(m_xcbConnectionManager.get());
         }
     }
 
     ////////////////////////////////////////////////////////////////////////////////////////////////
-    ApplicationLinux_xcb::~ApplicationLinux_xcb()
+    XcbApplication::~XcbApplication()
     {
-        if (LinuxXcbConnectionManagerInterface::Get() == m_xcbConnectionManager.get())
+        if (XcbConnectionManagerInterface::Get() == m_xcbConnectionManager.get())
         {
-            LinuxXcbConnectionManagerInterface::Unregister(m_xcbConnectionManager.get());
+            XcbConnectionManagerInterface::Unregister(m_xcbConnectionManager.get());
         }
         m_xcbConnectionManager.reset();
         LinuxLifecycleEvents::Bus::Handler::BusDisconnect();
     }
 
     ////////////////////////////////////////////////////////////////////////////////////////////////
-    void ApplicationLinux_xcb::PumpSystemEventLoopOnce()
+    void XcbApplication::PumpSystemEventLoopOnce()
     {
         if (xcb_connection_t* xcbConnection = m_xcbConnectionManager->GetXcbConnection())
         {
             if (xcb_generic_event_t* event = xcb_poll_for_event(xcbConnection))
             {
-                LinuxXcbEventHandlerBus::Broadcast(&LinuxXcbEventHandlerBus::Events::HandleXcbEvent, event);
+                XcbEventHandlerBus::Broadcast(&XcbEventHandlerBus::Events::HandleXcbEvent, event);
                 free(event);
             }
         }
     }
 
     ////////////////////////////////////////////////////////////////////////////////////////////////
-    void ApplicationLinux_xcb::PumpSystemEventLoopUntilEmpty()
+    void XcbApplication::PumpSystemEventLoopUntilEmpty()
     {
         if (xcb_connection_t* xcbConnection = m_xcbConnectionManager->GetXcbConnection())
         {
             while (xcb_generic_event_t* event = xcb_poll_for_event(xcbConnection))
             {
-                LinuxXcbEventHandlerBus::Broadcast(&LinuxXcbEventHandlerBus::Events::HandleXcbEvent, event);
+                XcbEventHandlerBus::Broadcast(&XcbEventHandlerBus::Events::HandleXcbEvent, event);
                 free(event);
             }
         }
     }
 
-#endif // PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB        
-
 } // namespace AzFramework

Code/Framework/AzFramework/Platform/Common/Xcb/AzFramework/XcbApplication.h

@@ -5,27 +5,24 @@
  * SPDX-License-Identifier: Apache-2.0 OR MIT
  *
  */
+
 #pragma once
 
 #include <AzFramework/API/ApplicationAPI_Platform.h>
 #include <AzFramework/Application/Application.h>
+#include <AzFramework/XcbConnectionManager.h>
 
-////////////////////////////////////////////////////////////////////////////////////////////////////
 namespace AzFramework
 {
-
+    class XcbApplication
-#if PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB
-
-    ////////////////////////////////////////////////////////////////////////////////////////////////
-    class ApplicationLinux_xcb
         : public Application::Implementation
         , public LinuxLifecycleEvents::Bus::Handler
     {
     public:
         ////////////////////////////////////////////////////////////////////////////////////////////
-        AZ_CLASS_ALLOCATOR(ApplicationLinux_xcb, AZ::SystemAllocator, 0);
+        AZ_CLASS_ALLOCATOR(XcbApplication, AZ::SystemAllocator, 0);
-        ApplicationLinux_xcb();
+        XcbApplication();
-        ~ApplicationLinux_xcb() override;
+        ~XcbApplication() override;
 
         ////////////////////////////////////////////////////////////////////////////////////////////
         // Application::Implementation
@@ -33,9 +30,6 @@ namespace AzFramework
         void PumpSystemEventLoopUntilEmpty() override;
 
     private:
-        AZStd::unique_ptr<LinuxXcbConnectionManager>    m_xcbConnectionManager;
+        AZStd::unique_ptr<XcbConnectionManager> m_xcbConnectionManager;
     };
-
-#endif // PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB
-
 } // namespace AzFramework

Code/Framework/AzFramework/Platform/Common/Xcb/AzFramework/XcbConnectionManager.h

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) Contributors to the Open 3D Engine Project.
+ * For complete copyright and license terms please see the LICENSE at the root of this distribution.
+ *
+ * SPDX-License-Identifier: Apache-2.0 OR MIT
+ *
+ */
+
+#pragma once
+
+#include <AzCore/EBus/EBus.h>
+#include <AzCore/Interface/Interface.h>
+#include <AzCore/RTTI/RTTI.h>
+
+#include <xcb/xcb.h>
+
+namespace AzFramework
+{
+    class XcbConnectionManager
+    {
+    public:
+        AZ_RTTI(XcbConnectionManager, "{1F756E14-8D74-42FD-843C-4863307710DB}");
+
+        virtual ~XcbConnectionManager() = default;
+
+        virtual xcb_connection_t* GetXcbConnection() const = 0;
+    };
+
+    class XcbConnectionManagerBusTraits
+        : public AZ::EBusTraits
+    {
+    public:
+        //////////////////////////////////////////////////////////////////////////
+        // EBusTraits overrides
+        static constexpr AZ::EBusHandlerPolicy HandlerPolicy = AZ::EBusHandlerPolicy::Single;
+        static constexpr AZ::EBusAddressPolicy AddressPolicy = AZ::EBusAddressPolicy::Single;
+        //////////////////////////////////////////////////////////////////////////
+    };
+
+    using XcbConnectionManagerBus = AZ::EBus<XcbConnectionManager, XcbConnectionManagerBusTraits>;
+    using XcbConnectionManagerInterface = AZ::Interface<XcbConnectionManager>;
+} // namespace AzFramework

Code/Framework/AzFramework/Platform/Common/Xcb/AzFramework/XcbEventHandler.h

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) Contributors to the Open 3D Engine Project.
+ * For complete copyright and license terms please see the LICENSE at the root of this distribution.
+ *
+ * SPDX-License-Identifier: Apache-2.0 OR MIT
+ *
+ */
+
+#pragma once
+
+#include <AzCore/EBus/EBus.h>
+#include <AzCore/RTTI/RTTI.h>
+
+#include <xcb/xcb.h>
+
+namespace AzFramework
+{
+    class XcbEventHandler
+    {
+    public:
+        AZ_RTTI(XcbEventHandler, "{3F756E14-8D74-42FD-843C-4863307710DB}");
+
+        virtual ~XcbEventHandler() = default;
+
+        virtual void HandleXcbEvent(xcb_generic_event_t* event) = 0;
+    };
+
+    class XcbEventHandlerBusTraits
+        : public AZ::EBusTraits
+    {
+    public:
+        //////////////////////////////////////////////////////////////////////////
+        // EBusTraits overrides
+        static constexpr AZ::EBusHandlerPolicy HandlerPolicy = AZ::EBusHandlerPolicy::Multiple;
+        static constexpr AZ::EBusAddressPolicy AddressPolicy = AZ::EBusAddressPolicy::Single;
+        //////////////////////////////////////////////////////////////////////////
+    };
+
+    using XcbEventHandlerBus = AZ::EBus<XcbEventHandler, XcbEventHandlerBusTraits>;
+} // namespace AzFramework

Code/Framework/AzFramework/Platform/Common/Xcb/AzFramework/XcbInputDeviceKeyboard.cpp

@@ -6,9 +6,10 @@
  *
  */
 
-#include <AzCore/std/typetraits/integral_constant.h>
-#include <AzFramework/API/ApplicationAPI_Linux.h>
 #include <AzFramework/Input/Devices/Keyboard/InputDeviceKeyboard.h>
+#include <AzFramework/XcbEventHandler.h>
+#include <AzFramework/XcbConnectionManager.h>
+#include <AzFramework/XcbInputDeviceKeyboard.h>
 
 #define explicit ExplicitIsACXXKeyword
 #include <xcb/xkb.h>
@@ -19,34 +20,26 @@
 
 namespace AzFramework
 {
-    class InputDeviceKeyboardXcb
+    XcbInputDeviceKeyboard::XcbInputDeviceKeyboard(InputDeviceKeyboard& inputDevice)
-        : public InputDeviceKeyboard::Implementation
-        , public LinuxXcbEventHandlerBus::Handler
-    {
-    public:
-        AZ_CLASS_ALLOCATOR(InputDeviceKeyboardXcb, AZ::SystemAllocator, 0);
-
-        using InputDeviceKeyboard::Implementation::Implementation;
-        InputDeviceKeyboardXcb(InputDeviceKeyboard& inputDevice)
         : InputDeviceKeyboard::Implementation(inputDevice)
     {
-            LinuxXcbEventHandlerBus::Handler::BusConnect();
+        XcbEventHandlerBus::Handler::BusConnect();
 
-            auto* interface = AzFramework::LinuxXcbConnectionManagerInterface::Get();
+        auto* interface = AzFramework::XcbConnectionManagerInterface::Get();
         if (!interface)
         {
             AZ_Warning("ApplicationLinux", false, "XCB interface not available");
             return;
         }
 
-            auto* connection = AzFramework::LinuxXcbConnectionManagerInterface::Get()->GetXcbConnection();
+        auto* connection = interface->GetXcbConnection();
         if (!connection)
         {
             AZ_Warning("ApplicationLinux", false, "XCB connection not available");
             return;
         }
 
-            AZStd::unique_ptr<xcb_xkb_use_extension_reply_t, DeleterForFreeFn<::std::free>> xkbUseExtensionReply{
+        XcbStdFreePtr<xcb_xkb_use_extension_reply_t> xkbUseExtensionReply{
             xcb_xkb_use_extension_reply(connection, xcb_xkb_use_extension(connection, 1, 0), nullptr)
         };
         if (!xkbUseExtensionReply)
@@ -69,32 +62,33 @@ namespace AzFramework
         m_initialized = true;
     }
 
-        bool IsConnected() const override
+    bool XcbInputDeviceKeyboard::IsConnected() const
     {
-            return m_initialized;
+        auto* connection = AzFramework::XcbConnectionManagerInterface::Get()->GetXcbConnection();
+        return connection && !xcb_connection_has_error(connection);
     }
 
-        bool HasTextEntryStarted() const override
+    bool XcbInputDeviceKeyboard::HasTextEntryStarted() const
     {
         return false;
     }
 
-        void TextEntryStart(const InputDeviceKeyboard::VirtualKeyboardOptions& options) override
+    void XcbInputDeviceKeyboard::TextEntryStart(const InputDeviceKeyboard::VirtualKeyboardOptions& options)
     {
     }
 
-        void TextEntryStop() override
+    void XcbInputDeviceKeyboard::TextEntryStop()
     {
     }
 
-        void TickInputDevice() override
+    void XcbInputDeviceKeyboard::TickInputDevice()
     {
         ProcessRawEventQueues();
     }
 
-        void HandleXcbEvent(xcb_generic_event_t* event) override
+    void XcbInputDeviceKeyboard::HandleXcbEvent(xcb_generic_event_t* event)
     {
-            if (!IsConnected())
+        if (!m_initialized)
         {
             return;
         }
@@ -126,8 +120,7 @@ namespace AzFramework
         }
     }
 
-    private:
+    [[nodiscard]] const InputChannelId* XcbInputDeviceKeyboard::InputChannelFromKeyEvent(xcb_keycode_t code) const
-        [[nodiscard]] const InputChannelId* InputChannelFromKeyEvent(xcb_keycode_t code) const
     {
         const xcb_keysym_t keysym = xkb_state_key_get_one_sym(m_xkbState.get(), code);
 
@@ -275,19 +268,4 @@ namespace AzFramework
             default: return nullptr;
         }
     }
-
-        template<auto freeFn>
-        using DeleterForFreeFn = AZStd::integral_constant<decltype(freeFn), freeFn>;
-
-        AZStd::unique_ptr<xkb_context, DeleterForFreeFn<xkb_context_unref>> m_xkbContext;
-        AZStd::unique_ptr<xkb_keymap, DeleterForFreeFn<xkb_keymap_unref>> m_xkbKeymap;
-        AZStd::unique_ptr<xkb_state, DeleterForFreeFn<xkb_state_unref>> m_xkbState;
-        int m_coreDeviceId{-1};
-        bool m_initialized{false};
-    };
-
-    InputDeviceKeyboard::Implementation* InputDeviceKeyboard::Implementation::Create(InputDeviceKeyboard& inputDevice)
-    {
-        return aznew InputDeviceKeyboardXcb(inputDevice);
-    }
 } // namespace AzFramework

Code/Framework/AzFramework/Platform/Common/Xcb/AzFramework/XcbInputDeviceKeyboard.h

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) Contributors to the Open 3D Engine Project.
+ * For complete copyright and license terms please see the LICENSE at the root of this distribution.
+ *
+ * SPDX-License-Identifier: Apache-2.0 OR MIT
+ *
+ */
+
+#include <AzFramework/Input/Devices/Keyboard/InputDeviceKeyboard.h>
+#include <AzFramework/XcbEventHandler.h>
+#include <AzFramework/XcbInterface.h>
+
+#include <xcb/xcb.h>
+#include <xkbcommon/xkbcommon.h>
+
+namespace AzFramework
+{
+    class XcbInputDeviceKeyboard
+        : public InputDeviceKeyboard::Implementation
+        , public XcbEventHandlerBus::Handler
+    {
+    public:
+        AZ_CLASS_ALLOCATOR(XcbInputDeviceKeyboard, AZ::SystemAllocator, 0);
+
+        using InputDeviceKeyboard::Implementation::Implementation;
+        XcbInputDeviceKeyboard(InputDeviceKeyboard& inputDevice);
+
+        bool IsConnected() const override;
+
+        bool HasTextEntryStarted() const override;
+        void TextEntryStart(const InputDeviceKeyboard::VirtualKeyboardOptions& options) override;
+        void TextEntryStop() override;
+        void TickInputDevice() override;
+
+        void HandleXcbEvent(xcb_generic_event_t* event) override;
+
+    private:
+        [[nodiscard]] const InputChannelId* InputChannelFromKeyEvent(xcb_keycode_t code) const;
+
+        XcbUniquePtr<xkb_context, xkb_context_unref> m_xkbContext;
+        XcbUniquePtr<xkb_keymap, xkb_keymap_unref> m_xkbKeymap;
+        XcbUniquePtr<xkb_state, xkb_state_unref> m_xkbState;
+        int m_coreDeviceId{-1};
+        bool m_initialized{false};
+    };
+} // namespace AzFramework

Code/Framework/AzFramework/Platform/Common/Xcb/AzFramework/XcbInterface.h

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) Contributors to the Open 3D Engine Project.
+ * For complete copyright and license terms please see the LICENSE at the root of this distribution.
+ *
+ * SPDX-License-Identifier: Apache-2.0 OR MIT
+ *
+ */
+
+#pragma once
+
+#include <xcb/xcb.h>
+
+#include <AzCore/std/smart_ptr/unique_ptr.h>
+
+namespace AzFramework
+{
+    // @brief Wrap a function pointer in a type
+    // This serves as a convenient way to wrap a function pointer in a given
+    // type. That type can then be used in a `unique_ptr` or `shared_ptr`.
+    // Using a type instead of a function pointer by value prevents the need to
+    // copy the pointer when copying the smart poiner.
+    template<auto Callable>
+    struct XcbDeleterFreeFunctionWrapper
+    {
+        using value_type = decltype(Callable);
+        static constexpr value_type s_value = Callable;
+        constexpr operator value_type() const noexcept
+        {
+            return s_value;
+        }
+    };
+
+    template<typename T, auto fn>
+    using XcbUniquePtr = AZStd::unique_ptr<T, XcbDeleterFreeFunctionWrapper<fn>>;
+
+    template<typename T>
+    using XcbStdFreePtr = XcbUniquePtr<T, ::free>;
+} // namespace AzFramework

Code/Framework/AzFramework/Platform/Common/Xcb/AzFramework/XcbNativeWindow.cpp

@@ -6,41 +6,37 @@
  *
  */
 
-#include <AzFramework/API/ApplicationAPI_Platform.h>
 #include <AzFramework/Application/Application.h>
 #include <AzFramework/Windowing/NativeWindow.h>
-#include <xcb/xcb.h>
+#include <AzFramework/XcbNativeWindow.h>
+#include <AzFramework/XcbConnectionManager.h>
 
-#include "NativeWindow_Linux_xcb.h"
+#include <xcb/xcb.h>
 
 namespace AzFramework
 {
-#if PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB
+    [[maybe_unused]] const char XcbErrorWindow[] = "XcbNativeWindow";
-
-    [[maybe_unused]] const char LinuxXcbErrorWindow[] = "NativeWindow_Linux_xcb";
     static constexpr uint8_t s_XcbFormatDataSize = 32;              // Format indicator for xcb for client messages
     static constexpr uint16_t s_DefaultXcbWindowBorderWidth = 4;    // The default border with in pixels if a border was specified
     static constexpr uint8_t s_XcbResponseTypeMask = 0x7f;          // Mask to extract the specific event type from an xcb event
 
     ////////////////////////////////////////////////////////////////////////////////////////////////
-    NativeWindowImpl_Linux_xcb::NativeWindowImpl_Linux_xcb() 
+    XcbNativeWindow::XcbNativeWindow() 
         : NativeWindow::Implementation()
     {
-        if (auto xcbConnectionManager = AzFramework::LinuxXcbConnectionManagerInterface::Get();
+        if (auto xcbConnectionManager = AzFramework::XcbConnectionManagerInterface::Get();
             xcbConnectionManager != nullptr)
         {
             m_xcbConnection = xcbConnectionManager->GetXcbConnection();
         }
-        AZ_Error(LinuxXcbErrorWindow, m_xcbConnection != nullptr, "Unable to get XCB Connection");
+        AZ_Error(XcbErrorWindow, m_xcbConnection != nullptr, "Unable to get XCB Connection");
     }
 
     ////////////////////////////////////////////////////////////////////////////////////////////////
-    NativeWindowImpl_Linux_xcb::~NativeWindowImpl_Linux_xcb()
+    XcbNativeWindow::~XcbNativeWindow() = default;
-    {
-    }
 
     ////////////////////////////////////////////////////////////////////////////////////////////////
-    void NativeWindowImpl_Linux_xcb::InitWindow(const AZStd::string& title,
+    void XcbNativeWindow::InitWindow(const AZStd::string& title,
                                                 const WindowGeometry& geometry,
                                                 const WindowStyleMasks& styleMasks)
     {
@@ -98,13 +94,13 @@ namespace AzFramework
         
         xcb_intern_atom_cookie_t cookieProtocol = xcb_intern_atom(m_xcbConnection, 1, strlen(wmProtocolString), wmProtocolString);
         xcb_intern_atom_reply_t* replyProtocol = xcb_intern_atom_reply(m_xcbConnection, cookieProtocol, nullptr);
-        AZ_Error(LinuxXcbErrorWindow, replyProtocol != nullptr, "Unable to query xcb '%s' atom", wmProtocolString);
+        AZ_Error(XcbErrorWindow, replyProtocol != nullptr, "Unable to query xcb '%s' atom", wmProtocolString);
         m_xcbAtomProtocols = replyProtocol->atom;
 
         const static char* wmDeleteWindowString = "WM_DELETE_WINDOW";
         xcb_intern_atom_cookie_t cookieDeleteWindow = xcb_intern_atom(m_xcbConnection, 0, strlen(wmDeleteWindowString), wmDeleteWindowString);
         xcb_intern_atom_reply_t* replyDeleteWindow = xcb_intern_atom_reply(m_xcbConnection, cookieDeleteWindow, nullptr);
-        AZ_Error(LinuxXcbErrorWindow, replyDeleteWindow != nullptr, "Unable to query xcb '%s' atom", wmDeleteWindowString);
+        AZ_Error(XcbErrorWindow, replyDeleteWindow != nullptr, "Unable to query xcb '%s' atom", wmDeleteWindowString);
         m_xcbAtomDeleteWindow = replyDeleteWindow->atom;
 
         xcbCheckResult = xcb_change_property_checked(m_xcbConnection, 
@@ -123,9 +119,9 @@ namespace AzFramework
     }
 
     ////////////////////////////////////////////////////////////////////////////////////////////////
-    void NativeWindowImpl_Linux_xcb::Activate()
+    void XcbNativeWindow::Activate()
     {
-        LinuxXcbEventHandlerBus::Handler::BusConnect();
+        XcbEventHandlerBus::Handler::BusConnect();
 
         if (!m_activated) // nothing to do if window was already activated
         {
@@ -137,7 +133,7 @@ namespace AzFramework
     }
 
     ////////////////////////////////////////////////////////////////////////////////////////////////
-    void NativeWindowImpl_Linux_xcb::Deactivate()
+    void XcbNativeWindow::Deactivate()
     {
         if (m_activated) // nothing to do if window was already deactivated
         {
@@ -148,17 +144,17 @@ namespace AzFramework
             xcb_unmap_window(m_xcbConnection, m_xcbWindow);
             xcb_flush(m_xcbConnection);
         }
-        LinuxXcbEventHandlerBus::Handler::BusDisconnect();
+        XcbEventHandlerBus::Handler::BusDisconnect();
     }    
 
     ////////////////////////////////////////////////////////////////////////////////////////////////
-    NativeWindowHandle NativeWindowImpl_Linux_xcb::GetWindowHandle() const
+    NativeWindowHandle XcbNativeWindow::GetWindowHandle() const
     {
         return reinterpret_cast<NativeWindowHandle>(m_xcbWindow);
     }
 
     ////////////////////////////////////////////////////////////////////////////////////////////////
-    void NativeWindowImpl_Linux_xcb::SetWindowTitle(const AZStd::string& title)
+    void XcbNativeWindow::SetWindowTitle(const AZStd::string& title)
     {
         xcb_void_cookie_t xcbCheckResult;
         xcbCheckResult = xcb_change_property(m_xcbConnection,
@@ -173,7 +169,7 @@ namespace AzFramework
     }
 
     ////////////////////////////////////////////////////////////////////////////////////////////////
-    void NativeWindowImpl_Linux_xcb::ResizeClientArea(WindowSize clientAreaSize)
+    void XcbNativeWindow::ResizeClientArea(WindowSize clientAreaSize)
     {
         const uint32_t values[] = { clientAreaSize.m_width, clientAreaSize.m_height };
 
@@ -184,7 +180,7 @@ namespace AzFramework
     }
 
     ////////////////////////////////////////////////////////////////////////////////////////////////
-    uint32_t NativeWindowImpl_Linux_xcb::GetDisplayRefreshRate() const
+    uint32_t XcbNativeWindow::GetDisplayRefreshRate() const
     {
         // [GFX TODO][GHI - 2678]
         // Using 60 for now until proper support is added
@@ -192,7 +188,7 @@ namespace AzFramework
     }
 
     ////////////////////////////////////////////////////////////////////////////////////////////////
-    bool NativeWindowImpl_Linux_xcb::ValidateXcbResult(xcb_void_cookie_t cookie)
+    bool XcbNativeWindow::ValidateXcbResult(xcb_void_cookie_t cookie)
     {
         bool result = true;
         if (xcb_generic_error_t* error = xcb_request_check(m_xcbConnection, cookie))
@@ -204,7 +200,7 @@ namespace AzFramework
     }
 
     ////////////////////////////////////////////////////////////////////////////////////////////////
-    void NativeWindowImpl_Linux_xcb::HandleXcbEvent(xcb_generic_event_t* event)
+    void XcbNativeWindow::HandleXcbEvent(xcb_generic_event_t* event)
     {
         switch (event->response_type & s_XcbResponseTypeMask)
         {
@@ -233,7 +229,7 @@ namespace AzFramework
     }
 
     ////////////////////////////////////////////////////////////////////////////////////////////////
-    void NativeWindowImpl_Linux_xcb::WindowSizeChanged(const uint32_t width, const uint32_t height)
+    void XcbNativeWindow::WindowSizeChanged(const uint32_t width, const uint32_t height)
     {
         if (m_width != width || m_height != height)
         {
@@ -246,7 +242,4 @@ namespace AzFramework
             }
         }
     }
-    
-#endif // PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB
-
 } // namespace AzFramework

Code/Framework/AzFramework/Platform/Common/Xcb/AzFramework/XcbNativeWindow.h

@@ -5,24 +5,25 @@
  * SPDX-License-Identifier: Apache-2.0 OR MIT
  *
  */
+
 #pragma once
 
-#include <AzFramework/API/ApplicationAPI_Platform.h>
 #include <AzFramework/Application/Application.h>
 #include <AzFramework/Windowing/NativeWindow.h>
+#include <AzFramework/XcbEventHandler.h>
+
 #include <xcb/xcb.h>
 
 namespace AzFramework
 {
-#if PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB
+    class XcbNativeWindow final
-    class NativeWindowImpl_Linux_xcb final
         : public NativeWindow::Implementation
-        , public LinuxXcbEventHandlerBus::Handler
+        , public XcbEventHandlerBus::Handler
     {
     public:
-        AZ_CLASS_ALLOCATOR(NativeWindowImpl_Linux_xcb, AZ::SystemAllocator, 0);
+        AZ_CLASS_ALLOCATOR(XcbNativeWindow, AZ::SystemAllocator, 0);
-        NativeWindowImpl_Linux_xcb();
+        XcbNativeWindow();
-        ~NativeWindowImpl_Linux_xcb() override;
+        ~XcbNativeWindow() override;
 
         ////////////////////////////////////////////////////////////////////////////////////////////
         // NativeWindow::Implementation
@@ -37,7 +38,7 @@ namespace AzFramework
         uint32_t GetDisplayRefreshRate() const override;        
 
         ////////////////////////////////////////////////////////////////////////////////////////////
-        // LinuxXcbEventHandlerBus::Handler
+        // XcbEventHandlerBus::Handler
         void HandleXcbEvent(xcb_generic_event_t* event) override;
 
     private:
@@ -49,6 +50,4 @@ namespace AzFramework
         xcb_atom_t          m_xcbAtomProtocols;
         xcb_atom_t          m_xcbAtomDeleteWindow;
     };
-#endif // PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB
-
 } // namespace AzFramework

Code/Framework/AzFramework/Platform/Common/Xcb/azframework_xcb_files.cmake

@@ -0,0 +1,18 @@
+#
+# Copyright (c) Contributors to the Open 3D Engine Project.
+# For complete copyright and license terms please see the LICENSE at the root of this distribution.
+#
+# SPDX-License-Identifier: Apache-2.0 OR MIT
+#
+#
+
+set(FILES
+    AzFramework/XcbApplication.cpp
+    AzFramework/XcbApplication.h
+    AzFramework/XcbConnectionManager.h
+    AzFramework/XcbInputDeviceKeyboard.cpp
+    AzFramework/XcbInputDeviceKeyboard.h
+    AzFramework/XcbInterface.h
+    AzFramework/XcbNativeWindow.cpp
+    AzFramework/XcbNativeWindow.h
+)

Code/Framework/AzFramework/Platform/Linux/AzFramework/API/ApplicationAPI_Linux.h

@@ -12,10 +12,6 @@
 #include <AzCore/Interface/Interface.h>
 #include <AzCore/EBus/EBus.h>
 
-#if PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB
-#include <xcb/xcb.h>
-#endif // LY_COMPILE_DEFINITIONS
-
 namespace AzFramework
 {
     class LinuxLifecycleEvents
@@ -30,54 +26,4 @@ namespace AzFramework
 
         using Bus = AZ::EBus<LinuxLifecycleEvents>;
     };
-
-#if PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB
-    class LinuxXcbConnectionManager
-    {
-    public:
-        AZ_RTTI(LinuxXcbConnectionManager, "{1F756E14-8D74-42FD-843C-4863307710DB}");
-
-        virtual ~LinuxXcbConnectionManager() = default;
-
-        virtual xcb_connection_t* GetXcbConnection() const = 0;
-    };
-
-    class LinuxXcbConnectionManagerBusTraits
-        : public AZ::EBusTraits
-    {
-        public:
-            //////////////////////////////////////////////////////////////////////////
-            // EBusTraits overrides
-            static constexpr AZ::EBusHandlerPolicy HandlerPolicy = AZ::EBusHandlerPolicy::Single;
-            static constexpr AZ::EBusAddressPolicy AddressPolicy = AZ::EBusAddressPolicy::Single;
-            //////////////////////////////////////////////////////////////////////////
-    };
-
-    using LinuxXcbConnectionManagerBus = AZ::EBus<LinuxXcbConnectionManager, LinuxXcbConnectionManagerBusTraits>;
-    using LinuxXcbConnectionManagerInterface = AZ::Interface<LinuxXcbConnectionManager>;
-    
-    class LinuxXcbEventHandler
-    {
-    public:
-        AZ_RTTI(LinuxXcbEventHandler, "{3F756E14-8D74-42FD-843C-4863307710DB}");
-
-        virtual ~LinuxXcbEventHandler() = default;
-
-        virtual void HandleXcbEvent(xcb_generic_event_t* event) = 0;
-    };
-
-    class LinuxXcbEventHandlerBusTraits
-        : public AZ::EBusTraits
-    {
-        public:
-            //////////////////////////////////////////////////////////////////////////
-            // EBusTraits overrides
-            static constexpr AZ::EBusHandlerPolicy HandlerPolicy = AZ::EBusHandlerPolicy::Multiple;
-            static constexpr AZ::EBusAddressPolicy AddressPolicy = AZ::EBusAddressPolicy::Single;
-            //////////////////////////////////////////////////////////////////////////
-    };
-
-    using LinuxXcbEventHandlerBus = AZ::EBus<LinuxXcbEventHandler, LinuxXcbEventHandlerBusTraits>;
-
-#endif // PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB
 } // namespace AzFramework

Code/Framework/AzFramework/Platform/Linux/AzFramework/Application/Application_Linux.cpp

@@ -8,7 +8,9 @@
 
 #include <AzFramework/Application/Application.h>
 
-#include "Application_Linux_xcb.h"
+#if PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB
+#include <AzFramework/XcbApplication.h>
+#endif
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 namespace AzFramework
@@ -17,7 +19,7 @@ namespace AzFramework
     Application::Implementation* Application::Implementation::Create()
     {
 #if PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB
-        return aznew ApplicationLinux_xcb();
+        return aznew XcbApplication();
 #elif PAL_TRAIT_LINUX_WINDOW_MANAGER_WAYLAND
         #error "Linux Window Manager Wayland not supported."
         return nullptr;

Code/Framework/AzFramework/Platform/Linux/AzFramework/Input/Devices/Keyboard/InputDeviceKeyboard_Linux.cpp

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) Contributors to the Open 3D Engine Project.
+ * For complete copyright and license terms please see the LICENSE at the root of this distribution.
+ *
+ * SPDX-License-Identifier: Apache-2.0 OR MIT
+ *
+ */
+
+#if PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB
+#include <AzFramework/XcbInputDeviceKeyboard.h>
+#endif
+
+namespace AzFramework
+{
+    InputDeviceKeyboard::Implementation* InputDeviceKeyboard::Implementation::Create(InputDeviceKeyboard& inputDevice)
+    {
+#if PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB
+        return aznew XcbInputDeviceKeyboard(inputDevice);
+#elif PAL_TRAIT_LINUX_WINDOW_MANAGER_WAYLAND
+        #error "Linux Window Manager Wayland not supported."
+        return nullptr;
+#else
+        #error "Linux Window Manager not recognized."
+        return nullptr;
+#endif // PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB
+    }
+} // namespace AzFramework

Code/Framework/AzFramework/Platform/Linux/AzFramework/Windowing/NativeWindow_Linux.cpp

@@ -6,14 +6,16 @@
  *
  */
 
-#include "NativeWindow_Linux_xcb.h"
+#if PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB
+#include <AzFramework/XcbNativeWindow.h>
+#endif
 
 namespace AzFramework
 {
     NativeWindow::Implementation* NativeWindow::Implementation::Create()
     {
 #if PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB
-        return aznew NativeWindowImpl_Linux_xcb();
+        return aznew XcbNativeWindow();
 #elif PAL_TRAIT_LINUX_WINDOW_MANAGER_WAYLAND
         #error "Linux Window Manager Wayland not supported."
         return nullptr;
@@ -22,5 +24,4 @@ namespace AzFramework
         return nullptr;
 #endif // PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB
     }
-
 } // namespace AzFramework

Code/Framework/AzFramework/Platform/Linux/platform_linux.cmake

@@ -10,6 +10,14 @@
 # Only 'xcb' and 'wayland' are recognized
 if (${PAL_TRAIT_LINUX_WINDOW_MANAGER} STREQUAL "xcb")
 
+    set(LY_COMPILE_DEFINITIONS PUBLIC PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB)
+    set(LY_INCLUDE_DIRECTORIES
+        PUBLIC
+            Platform/Common/Xcb
+    )
+    set(LY_FILES_CMAKE
+        Platform/Common/Xcb/azframework_xcb_files.cmake
+    )
     set(LY_BUILD_DEPENDENCIES
         PRIVATE
             3rdParty::X11::xcb
@@ -18,8 +26,6 @@ if (${PAL_TRAIT_LINUX_WINDOW_MANAGER} STREQUAL "xcb")
             3rdParty::X11::xkbcommon_X11
     )
 
-    set(LY_COMPILE_DEFINITIONS PUBLIC PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB)
-
 elseif(PAL_TRAIT_LINUX_WINDOW_MANAGER STREQUAL "wayland")
 
     set(LY_COMPILE_DEFINITIONS PUBLIC PAL_TRAIT_LINUX_WINDOW_MANAGER_WAYLAND)

Code/Framework/AzFramework/Platform/Linux/platform_linux_files.cmake

@@ -12,8 +12,6 @@ set(FILES
     AzFramework/API/ApplicationAPI_Platform.h
     AzFramework/API/ApplicationAPI_Linux.h
     AzFramework/Application/Application_Linux.cpp
-    AzFramework/Application/Application_Linux_xcb.h
-    AzFramework/Application/Application_Linux_xcb.cpp
     AzFramework/Asset/AssetSystemComponentHelper_Linux.cpp
     AzFramework/Process/ProcessWatcher_Linux.cpp
     AzFramework/Process/ProcessCommon.h
@@ -22,10 +20,8 @@ set(FILES
     ../Common/Unimplemented/AzFramework/StreamingInstall/StreamingInstall_Unimplemented.cpp
     ../Common/Default/AzFramework/TargetManagement/TargetManagementComponent_Default.cpp
     AzFramework/Windowing/NativeWindow_Linux.cpp
-    AzFramework/Windowing/NativeWindow_Linux_xcb.h
-    AzFramework/Windowing/NativeWindow_Linux_xcb.cpp
     ../Common/Unimplemented/AzFramework/Input/Devices/Gamepad/InputDeviceGamepad_Unimplemented.cpp
-    AzFramework/Input/Devices/Keyboard/InputDeviceKeyboard_xcb.cpp
+    AzFramework/Input/Devices/Keyboard/InputDeviceKeyboard_Linux.cpp
     ../Common/Unimplemented/AzFramework/Input/Devices/Motion/InputDeviceMotion_Unimplemented.cpp
     ../Common/Unimplemented/AzFramework/Input/Devices/Mouse/InputDeviceMouse_Unimplemented.cpp
     ../Common/Unimplemented/AzFramework/Input/Devices/Touch/InputDeviceTouch_Unimplemented.cpp

Gems/Atom/RHI/Vulkan/Code/Source/Platform/Linux/RHI/WSISurface_Linux.cpp

@@ -10,6 +10,10 @@
 #include <RHI/Instance.h>
 #include <RHI/WSISurface.h>
 
+#if PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB
+#include <AzFramework/XcbConnectionManager.h>
+#endif
+
 namespace AZ
 {
     namespace Vulkan
@@ -21,7 +25,7 @@ namespace AZ
 #if PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB
 
             xcb_connection_t* xcb_connection = nullptr;
-            if (auto xcbConnectionManager = AzFramework::LinuxXcbConnectionManagerInterface::Get();
+            if (auto xcbConnectionManager = AzFramework::XcbConnectionManagerInterface::Get();
                 xcbConnectionManager != nullptr)
             {
                 xcb_connection = xcbConnectionManager->GetXcbConnection();