Share GraphicsBitmaps between the windowing server and the client process.

This is pretty cool. :^)

GraphicsBitmaps are now mapped into both the server and the client address
space (usually at different addresses but that doesn't matter.)

Added a GUI syscall for getting a window's backing store, and another one
for invalidating a window so that the server redraws it.

Kernel/GUITypes.h

@@ -33,6 +33,13 @@ struct GUI_CreateWindowParameters {
     char title[128];
 };
 
+struct GUI_WindowBackingStoreInfo {
+    GUI_Size size;
+    size_t bpp;
+    size_t pitch;
+    RGBA32* pixels;
+};
+
 enum class GUI_MouseButton : unsigned char {
     NoButton = 0,
     Left = 1,

Kernel/Process.h

@@ -192,6 +192,8 @@ public:
 
     int gui$create_window(const GUI_CreateWindowParameters*);
     int gui$destroy_window(int window_id);
+    int gui$get_window_backing_store(int window_id, GUI_WindowBackingStoreInfo*);
+    int gui$invalidate_window(int window_id);
 
     DisplayInfo get_display_info();
 

Kernel/ProcessGUI.cpp

@@ -25,8 +25,11 @@ void Process::initialize_gui_statics()
 int Process::make_window_id()
 {
     int new_id = m_next_window_id++;
-    while (!new_id || m_windows.contains(new_id))
+    while (!new_id || m_windows.contains(new_id)) {
         new_id = m_next_window_id++;
+        if (new_id < 0)
+            new_id = 1;
+    }
     return new_id;
 }
 
@@ -74,11 +77,40 @@ int Process::gui$destroy_window(int window_id)
     dbgprintf("%s<%u> gui$destroy_window (window_id=%d)\n", name().characters(), pid(), window_id);
     if (window_id < 0)
         return -EINVAL;
-    if (window_id >= static_cast<int>(m_windows.size()))
-        return -EBADWINDOW;
     auto it = m_windows.find(window_id);
     if (it == m_windows.end())
         return -EBADWINDOW;
     m_windows.remove(window_id);
     return 0;
 }
+
+int Process::gui$get_window_backing_store(int window_id, GUI_WindowBackingStoreInfo* info)
+{
+    dbgprintf("%s<%u> gui$get_window_backing_store (window_id=%d, info=%p)\n", name().characters(), pid(), window_id, info);
+    if (!validate_write_typed(info))
+        return -EFAULT;
+    if (window_id < 0)
+        return -EINVAL;
+    auto it = m_windows.find(window_id);
+    if (it == m_windows.end())
+        return -EBADWINDOW;
+    auto& window = *(*it).value;
+    info->bpp = sizeof(RGBA32);
+    info->pitch = window.backing()->pitch();
+    info->size = window.backing()->size();
+    info->pixels = reinterpret_cast<RGBA32*>(window.backing()->client_region()->linearAddress.asPtr());
+    return 0;
+}
+
+int Process::gui$invalidate_window(int window_id)
+{
+    dbgprintf("%s<%u> gui$invalidate_window (window_id=%d)\n", name().characters(), pid(), window_id);
+    if (window_id < 0)
+        return -EINVAL;
+    auto it = m_windows.find(window_id);
+    if (it == m_windows.end())
+        return -EBADWINDOW;
+    auto& window = *(*it).value;
+    WindowManager::the().invalidate(window);
+    return 0;
+}

Kernel/Syscall.cpp

@@ -191,6 +191,10 @@ static dword handle(RegisterDump& regs, dword function, dword arg1, dword arg2,
         return current->gui$create_window((const GUI_CreateWindowParameters*)arg1);
     case Syscall::SC_gui_destroy_window:
         return current->gui$destroy_window((int)arg1);
+    case Syscall::SC_gui_get_window_backing_store:
+        return current->gui$get_window_backing_store((int)arg1, (GUI_WindowBackingStoreInfo*)arg2);
+    case Syscall::SC_gui_invalidate_window:
+        return current->gui$invalidate_window((int)arg1);
     default:
         kprintf("<%u> int0x80: Unknown function %u requested {%x, %x, %x}\n", current->pid(), function, arg1, arg2, arg3);
         break;

Kernel/Syscall.h

@@ -68,6 +68,9 @@
     __ENUMERATE_SYSCALL(sync) \
     __ENUMERATE_SYSCALL(gui_create_window) \
     __ENUMERATE_SYSCALL(gui_destroy_window) \
+    __ENUMERATE_SYSCALL(gui_get_window_backing_store) \
+    __ENUMERATE_SYSCALL(gui_invalidate_window) \
+
 
 namespace Syscall {