Add basic GUI API for creating labels and buttons.

AK/WeakPtr.h

@@ -11,6 +11,12 @@ public:
     WeakPtr() { }
     WeakPtr(std::nullptr_t) { }
 
+    template<typename U>
+    WeakPtr(WeakPtr<U>&& other)
+        : m_link(reinterpret_cast<WeakLink<T>*>(other.leakLink()))
+    {
+    }
+
     template<typename U>
     WeakPtr& operator=(WeakPtr<U>&& other)
     {

Kernel/GUITypes.h

@@ -21,3 +21,17 @@ struct GUI_CreateWindowParameters {
     unsigned flags;
     char title[128];
 };
+
+enum class GUI_WidgetType : unsigned {
+    Label,
+    Button,
+};
+
+struct GUI_CreateWidgetParameters {
+    GUI_WidgetType type;
+    GUI_Rect rect;
+    GUI_Color background_color;
+    bool opaque;
+    unsigned flags;
+    char text[256];
+};

Kernel/Process.h

@@ -11,6 +11,7 @@
 #include <AK/InlineLinkedList.h>
 #include <AK/AKString.h>
 #include <AK/Vector.h>
+#include <AK/WeakPtr.h>
 
 class FileDescriptor;
 class PageDirectory;
@@ -18,6 +19,7 @@ class Region;
 class VMObject;
 class Zone;
 class Window;
+class Widget;
 
 #define COOL_GLOBALS
 #ifdef COOL_GLOBALS
@@ -189,6 +191,8 @@ public:
 
     int gui$create_window(const GUI_CreateWindowParameters*);
     int gui$destroy_window(int window_id);
+    int gui$create_widget(int window_id, const GUI_CreateWidgetParameters*);
+    int gui$destroy_widget(int widget_id);
 
     DisplayInfo get_display_info();
 
@@ -338,7 +342,8 @@ private:
 
     RetainPtr<Region> m_display_framebuffer_region;
 
-    Vector<Window*> m_windows;
+    Vector<WeakPtr<Window>> m_windows;
+    Vector<WeakPtr<Widget>> m_widgets;
 };
 
 extern Process* current;

Kernel/ProcessGUI.cpp

@@ -5,6 +5,8 @@
 #include <Widgets/FrameBuffer.h>
 #include <Widgets/EventLoop.h>
 #include <Widgets/Font.h>
+#include <Widgets/Button.h>
+#include <Widgets/Label.h>
 #include <Widgets/Widget.h>
 #include <Widgets/Window.h>
 #include <Widgets/WindowManager.h>
@@ -34,7 +36,7 @@ int Process::gui$create_window(const GUI_CreateWindowParameters* user_params)
     if (!validate_read_typed(user_params))
         return -EFAULT;
 
-    GUI_CreateWindowParameters params = *user_params;
+    auto params = *user_params;
     Rect rect { params.rect.x, params.rect.y, params.rect.width, params.rect.height };
 
     if (rect.is_empty())
@@ -47,7 +49,7 @@ int Process::gui$create_window(const GUI_CreateWindowParameters* user_params)
         return -ENOMEM;
 
     int window_id = m_windows.size();
-    m_windows.append(window);
+    m_windows.append(window->makeWeakPtr());
 
     window->setTitle(params.title);
     window->setRect(rect);
@@ -64,14 +66,71 @@ int Process::gui$create_window(const GUI_CreateWindowParameters* user_params)
 
 int Process::gui$destroy_window(int window_id)
 {
-    wait_for_gui_server();
     dbgprintf("%s<%u> gui$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 -EBADWIN;
-    auto* window = m_windows[window_id];
-    m_windows.remove(window_id);
+        return -EBADWINDOW;
+    auto* window = m_windows[window_id].ptr();
+    if (!window)
+        return -EBADWINDOW;
     window->deleteLater();
     return 0;
 }
+
+int Process::gui$create_widget(int window_id, const GUI_CreateWidgetParameters* user_params)
+{
+    if (!validate_read_typed(user_params))
+        return -EFAULT;
+
+    if (window_id < 0)
+        return -EINVAL;
+    if (window_id >= static_cast<int>(m_windows.size()))
+        return -EINVAL;
+    if (!m_windows[window_id])
+        return -EINVAL;
+    auto& window = *m_windows[window_id];
+
+    auto params = *user_params;
+    Rect rect { params.rect.x, params.rect.y, params.rect.width, params.rect.height };
+
+    if (rect.is_empty())
+        return -EINVAL;
+
+    Widget* widget = nullptr;
+    switch (params.type) {
+    case GUI_WidgetType::Label:
+        widget = new Label(window.mainWidget());
+        static_cast<Label*>(widget)->setText(params.text);
+        break;
+    case GUI_WidgetType::Button:
+        widget = new Button(window.mainWidget());
+        static_cast<Button*>(widget)->setCaption(params.text);
+        break;
+    }
+
+    int widget_id = m_widgets.size();
+    m_widgets.append(widget->makeWeakPtr());
+
+    widget->setWindowRelativeRect(rect);
+    widget->setBackgroundColor(params.background_color);
+    widget->setFillWithBackgroundColor(params.opaque);
+    dbgprintf("%s<%u> gui$create_widget: %d with rect {%d,%d %dx%d}\n", name().characters(), pid(), widget_id, rect.x(), rect.y(), rect.width(), rect.height());
+
+    return window_id;
+}
+
+int Process::gui$destroy_widget(int widget_id)
+{
+    dbgprintf("%s<%u> gui$destroy_widget (widget_id=%d)\n", name().characters(), pid(), widget_id);
+    if (widget_id < 0)
+        return -EINVAL;
+    if (widget_id >= static_cast<int>(m_widgets.size()))
+        return -EBADWINDOW;
+    auto* widget = m_widgets[widget_id].ptr();
+    if (!widget)
+        return -EBADWIDGET;
+    widget->deleteLater();
+    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_create_widget:
+        return current->gui$create_widget((int)arg1, (const GUI_CreateWidgetParameters*)arg2);
+    case Syscall::SC_gui_destroy_widget:
+        return current->gui$destroy_widget((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 +68,8 @@
     __ENUMERATE_SYSCALL(sync) \
     __ENUMERATE_SYSCALL(gui_create_window) \
     __ENUMERATE_SYSCALL(gui_destroy_window) \
+    __ENUMERATE_SYSCALL(gui_create_widget) \
+    __ENUMERATE_SYSCALL(gui_destroy_widget) \
 
 namespace Syscall {
 

LibC/errno_numbers.h

@@ -42,7 +42,8 @@
     __ERROR(ENOTIMPL,       "Not implemented") \
     __ERROR(EAFNOSUPPORT,   "Address family not supported") \
     __ERROR(EWHYTHO,        "Failed without setting an error code (Bug!)") \
-    __ERROR(EBADWIN,        "Bad WindowID") \
+    __ERROR(EBADWINDOW,     "Bad Window ID") \
+    __ERROR(EBADWIDGET,     "Bad Widget ID") \
 
 enum __errno_values {
 #undef __ERROR