AK: Add Eternal<T> and use it in various places.

This is useful for static locals that never need to be destroyed:

Thing& Thing::the()
{
    static Eternal<Thing> the;
    return the;
}

The object will be allocated in data segment memory and will never have
its destructor invoked.

AK/Eternal.h

@@ -0,0 +1,30 @@
+#pragma once
+
+#include <AK/StdLibExtras.h>
+
+namespace AK {
+
+template<typename T>
+class Eternal {
+public:
+    template<typename... Args>
+    Eternal(Args&&... args)
+    {
+        new (m_slot) T(forward<Args>(args)...);
+    }
+
+    T& get() { return *reinterpret_cast<T*>(&m_slot); }
+    const T& get() const { return *reinterpret_cast<T*>(&m_slot); }
+    T* operator->() { return &get(); }
+    const T* operator->() const { return &get(); }
+    operator T&() { return get(); }
+    operator const T&() const { return get(); }
+
+
+private:
+    [[gnu::aligned(alignof(T))]] char m_slot[sizeof(T)];
+};
+
+}
+
+using AK::Eternal;

AK/kmalloc.h

@@ -8,6 +8,7 @@
 #define AK_MAKE_ETERNAL \
 public: \
     void* operator new(size_t size) { return kmalloc_eternal(size); } \
+    void* operator new(size_t, void* ptr) { return ptr; } \
 private:
 #else
 #define AK_MAKE_ETERNAL

Applications/ProcessManager/MemoryStatsWidget.cpp

@@ -106,5 +106,5 @@ void MemoryStatsWidget::paint_event(GPaintEvent& event)
 {
     GPainter painter(*this);
     painter.add_clip_rect(event.rect());
-    StylePainter::the().paint_surface(painter, rect());
+    StylePainter::paint_surface(painter, rect());
 }

Kernel/Net/LoopbackAdapter.cpp

@@ -1,11 +1,10 @@
 #include <Kernel/Net/LoopbackAdapter.h>
+#include <AK/Eternal.h>
 
 LoopbackAdapter& LoopbackAdapter::the()
 {
-    static LoopbackAdapter* the;
-    if (!the)
-        the = new LoopbackAdapter;
-    return *the;
+    static Eternal<LoopbackAdapter> the;
+    return the;
 }
 
 LoopbackAdapter::LoopbackAdapter()

Kernel/Net/LoopbackAdapter.h

@@ -6,12 +6,11 @@ class LoopbackAdapter final : public NetworkAdapter {
     AK_MAKE_ETERNAL
 public:
     static LoopbackAdapter& the();
-
-    virtual ~LoopbackAdapter() override;
+    LoopbackAdapter();
 
     virtual void send_raw(const byte*, int) override;
     virtual const char* class_name() const override { return "LoopbackAdapter"; }
 
 private:
-    LoopbackAdapter();
+    virtual ~LoopbackAdapter() override;
 };

Kernel/Net/NetworkTask.cpp

@@ -12,7 +12,7 @@
 #include <Kernel/Process.h>
 #include <Kernel/Net/EtherType.h>
 #include <Kernel/Lock.h>
-
+#include <AK/Eternal.h>
 
 //#define ETHERNET_DEBUG
 #define IPV4_DEBUG
@@ -28,10 +28,8 @@ static void handle_tcp(const EthernetFrameHeader&, int frame_size);
 
 Lockable<HashMap<IPv4Address, MACAddress>>& arp_table()
 {
-    static Lockable<HashMap<IPv4Address, MACAddress>>* the;
-    if (!the)
-        the = new Lockable<HashMap<IPv4Address, MACAddress>>;
-    return *the;
+    static Eternal<Lockable<HashMap<IPv4Address, MACAddress>>> the;
+    return the;
 }
 
 void NetworkTask_main()

Kernel/StdLib.cpp

@@ -145,4 +145,14 @@ int memcmp(const void* v1, const void* v2, size_t n)
     ASSERT_NOT_REACHED();
 }
 
+void __cxa_guard_acquire(void*)
+{
+    // FIXME: Lock somehow?
+}
+
+void __cxa_guard_release(void*)
+{
+    // FIXME: Unlock somehow?
+}
+
 }

LibGUI/GButton.cpp

@@ -26,7 +26,7 @@ void GButton::paint_event(GPaintEvent& event)
     GPainter painter(*this);
     painter.add_clip_rect(event.rect());
 
-    StylePainter::the().paint_button(painter, rect(), m_button_style, m_being_pressed, m_hovered);
+    StylePainter::paint_button(painter, rect(), m_button_style, m_being_pressed, m_hovered);
 
     if (!caption().is_empty() || m_icon) {
         auto content_rect = rect();

LibGUI/GClipboard.cpp

@@ -3,19 +3,7 @@
 #include <WindowServer/WSAPITypes.h>
 #include <LibC/SharedBuffer.h>
 
-GClipboard& GClipboard::the()
-{
-    static GClipboard* s_the;
-    if (!s_the)
-        s_the = new GClipboard;
-    return *s_the;
-}
-
-GClipboard::GClipboard()
-{
-}
-
-String GClipboard::data() const
+String GClipboard::data()
 {
     WSAPI_ClientMessage request;
     request.type = WSAPI_ClientMessage::Type::GetClipboardContents;

LibGUI/GClipboard.h

@@ -4,11 +4,6 @@
 
 class GClipboard {
 public:
-    static GClipboard& the();
-
-    String data() const;
-    void set_data(const String&);
-
-private:
-    GClipboard();
+    static String data();
+    static void set_data(const String&);
 };

LibGUI/GDesktop.cpp

@@ -1,13 +1,12 @@
 #include <LibGUI/GDesktop.h>
 #include <LibGUI/GEventLoop.h>
+#include <AK/Eternal.h>
 #include <string.h>
 
 GDesktop& GDesktop::the()
 {
-    static GDesktop* s_the;
-    if (!s_the)
-        s_the = new GDesktop;
-    return *s_the;
+    static Eternal<GDesktop> the;
+    return the;
 }
 
 GDesktop::GDesktop()

LibGUI/GDesktop.h

@@ -6,12 +6,11 @@
 class GDesktop {
 public:
     static GDesktop& the();
+    GDesktop();
 
     String wallpaper() const;
     bool set_wallpaper(const String& path);
 
 private:
-    GDesktop();
-
     Rect m_rect;
 };

LibGUI/GFontDatabase.cpp

@@ -1,16 +1,14 @@
 #include <LibGUI/GFontDatabase.h>
 #include <SharedGraphics/Font.h>
+#include <AK/Eternal.h>
 #include <dirent.h>
 #include <stdio.h>
 #include <stdlib.h>
 
-static GFontDatabase* s_the;
-
 GFontDatabase& GFontDatabase::the()
 {
-    if (!s_the)
-        s_the = new GFontDatabase;
-    return *s_the;
+    static Eternal<GFontDatabase> the;
+    return the;
 }
 
 GFontDatabase::GFontDatabase()

LibGUI/GFontDatabase.h

@@ -9,13 +9,13 @@ class Font;
 class GFontDatabase {
 public:
     static GFontDatabase& the();
+    GFontDatabase();
 
     RetainPtr<Font> get_by_name(const String&);
     void for_each_font(Function<void(const String&)>);
     void for_each_fixed_width_font(Function<void(const String&)>);
 
 private:
-    GFontDatabase();
     ~GFontDatabase();
 
     struct Metadata {

LibGUI/GScrollBar.cpp

@@ -197,14 +197,14 @@ void GScrollBar::paint_event(GPaintEvent& event)
 
     painter.fill_rect(rect(), Color::from_rgb(0xd6d2ce));
 
-    StylePainter::the().paint_button(painter, up_button_rect(), ButtonStyle::Normal, false);
+    StylePainter::paint_button(painter, up_button_rect(), ButtonStyle::Normal, false);
     painter.draw_bitmap(up_button_rect().location().translated(3, 3), orientation() == Orientation::Vertical ? *s_up_arrow_bitmap : *s_left_arrow_bitmap, has_scrubber() ? Color::Black : Color::MidGray);
 
-    StylePainter::the().paint_button(painter, down_button_rect(), ButtonStyle::Normal, false);
+    StylePainter::paint_button(painter, down_button_rect(), ButtonStyle::Normal, false);
     painter.draw_bitmap(down_button_rect().location().translated(3, 3), orientation() == Orientation::Vertical ? *s_down_arrow_bitmap : *s_right_arrow_bitmap, has_scrubber() ? Color::Black : Color::MidGray);
 
     if (has_scrubber())
-        StylePainter::the().paint_button(painter, scrubber_rect(), ButtonStyle::Normal, false);
+        StylePainter::paint_button(painter, scrubber_rect(), ButtonStyle::Normal, false);
 }
 
 void GScrollBar::mousedown_event(GMouseEvent& event)

LibGUI/GStatusBar.cpp

@@ -37,5 +37,5 @@ void GStatusBar::paint_event(GPaintEvent& event)
 {
     GPainter painter(*this);
     painter.add_clip_rect(event.rect());
-    StylePainter::the().paint_surface(painter, rect(), !spans_entire_window_horizontally());
+    StylePainter::paint_surface(painter, rect(), !spans_entire_window_horizontally());
 }

LibGUI/GTextEditor.cpp

@@ -785,7 +785,7 @@ void GTextEditor::cut()
 {
     auto selected_text = this->selected_text();
     printf("Cut: \"%s\"\n", selected_text.characters());
-    GClipboard::the().set_data(selected_text);
+    GClipboard::set_data(selected_text);
     delete_selection();
 }
 
@@ -793,12 +793,12 @@ void GTextEditor::copy()
 {
     auto selected_text = this->selected_text();
     printf("Copy: \"%s\"\n", selected_text.characters());
-    GClipboard::the().set_data(selected_text);
+    GClipboard::set_data(selected_text);
 }
 
 void GTextEditor::paste()
 {
-    auto paste_text = GClipboard::the().data();
+    auto paste_text = GClipboard::data();
     printf("Paste: \"%s\"\n", paste_text.characters());
     insert_at_cursor_or_replace_selection(paste_text);
 }

LibGUI/GToolBar.cpp

@@ -79,5 +79,5 @@ void GToolBar::paint_event(GPaintEvent& event)
 {
     GPainter painter(*this);
     painter.add_clip_rect(event.rect());
-    StylePainter::the().paint_surface(painter, rect(), !spans_entire_window_horizontally());
+    StylePainter::paint_surface(painter, rect(), !spans_entire_window_horizontally());
 }

Servers/WindowServer/WSClipboard.cpp

@@ -1,11 +1,10 @@
 #include <WindowServer/WSClipboard.h>
+#include <AK/Eternal.h>
 
 WSClipboard& WSClipboard::the()
 {
-    static WSClipboard* s_the;
-    if (!s_the)
-        s_the = new WSClipboard;
-    return *s_the;
+    static Eternal<WSClipboard> the;
+    return the;
 }
 
 WSClipboard::WSClipboard()

Servers/WindowServer/WSClipboard.h

@@ -7,7 +7,7 @@
 class WSClipboard final : public WSMessageReceiver {
 public:
     static WSClipboard& the();
-    virtual ~WSClipboard() override;
+    WSClipboard();
 
     bool has_data() const
     {
@@ -21,7 +21,7 @@ public:
     void set_data(Retained<SharedBuffer>&&, int contents_size);
 
 private:
-    WSClipboard();
+    virtual ~WSClipboard() override;
     virtual void on_message(const WSMessage&) override;
 
     RetainPtr<SharedBuffer> m_shared_buffer;

Servers/WindowServer/WSWindowManager.cpp

@@ -473,7 +473,7 @@ void WSWindowManager::paint_window_frame(const WSWindow& window)
     if (!s_close_button_bitmap)
         s_close_button_bitmap = &CharacterBitmap::create_from_ascii(s_close_button_bitmap_data, s_close_button_bitmap_width, s_close_button_bitmap_height).leak_ref();
 
-    StylePainter::the().paint_button(*m_back_painter, close_button_rect, ButtonStyle::Normal, false, false);
+    StylePainter::paint_button(*m_back_painter, close_button_rect, ButtonStyle::Normal, false, false);
 
     auto x_location = close_button_rect.center();
     x_location.move_by(-(s_close_button_bitmap_width / 2), -(s_close_button_bitmap_height / 2));

SharedGraphics/StylePainter.cpp

@@ -1,19 +1,6 @@
 #include <SharedGraphics/StylePainter.h>
 #include <LibGUI/GPainter.h>
 
-static StylePainter* s_the;
-
-StylePainter& StylePainter::the()
-{
-    if (!s_the)
-        s_the = new StylePainter;
-    return *s_the;
-}
-
-StylePainter::StylePainter()
-{
-}
-
 static void paint_button_new(Painter& painter, const Rect& rect, bool pressed)
 {
     Color button_color = Color::from_rgb(0xc0c0c0);

SharedGraphics/StylePainter.h

@@ -7,11 +7,6 @@ enum class ButtonStyle { Normal, CoolBar, OldNormal };
 
 class StylePainter {
 public:
-    static StylePainter& the();
-
-    void paint_button(Painter&, const Rect&, ButtonStyle, bool pressed, bool hovered = false);
-    void paint_surface(Painter&, const Rect&, bool paint_vertical_lines = true);
-
-private:
-    StylePainter();
+    static void paint_button(Painter&, const Rect&, ButtonStyle, bool pressed, bool hovered = false);
+    static void paint_surface(Painter&, const Rect&, bool paint_vertical_lines = true);
 };