Start working on a GUI kernel API.

Kernel/GUITypes.h

@@ -0,0 +1,23 @@
+#pragma once
+
+// GUI system call API types.
+
+struct GUI_Rect {
+    int x;
+    int y;
+    int width;
+    int height;
+};
+
+struct GUI_WindowFlags { enum {
+    Visible = 1 << 0,
+}; };
+
+typedef unsigned GUI_Color;
+
+struct GUI_CreateWindowParameters {
+    GUI_Rect rect;
+    GUI_Color background_color;
+    unsigned flags;
+    char title[128];
+};

Kernel/Makefile

@@ -5,6 +5,7 @@ KERNEL_OBJS = \
        StdLib.o \
        i386.o \
        Process.o \
+       ProcessGUI.o \
        i8253.o \
        Keyboard.o \
        CMOS.o \

Kernel/Process.cpp

@@ -54,6 +54,7 @@ void Process::initialize()
     g_processes = new InlineLinkedList<Process>;
     s_hostname = new String("courage");
     Scheduler::initialize();
+    initialize_gui_statics();
 }
 
 Vector<Process*> Process::allProcesses()

Kernel/Process.h

@@ -5,6 +5,7 @@
 #include "i386.h"
 #include "TTY.h"
 #include "Syscall.h"
+#include "GUITypes.h"
 #include <VirtualFileSystem/VirtualFileSystem.h>
 #include <VirtualFileSystem/UnixTypes.h>
 #include <AK/InlineLinkedList.h>
@@ -16,6 +17,7 @@ class PageDirectory;
 class Region;
 class VMObject;
 class Zone;
+class Window;
 
 #define COOL_GLOBALS
 #ifdef COOL_GLOBALS
@@ -185,9 +187,13 @@ public:
     Unix::clock_t sys$times(Unix::tms*);
     int sys$utime(const char* pathname, const struct Unix::utimbuf*);
 
+    int gui$create_window(const GUI_CreateWindowParameters*);
+    int gui$destroy_window(int window_id);
+
     DisplayInfo get_display_info();
 
     static void initialize();
+    static void initialize_gui_statics();
 
     void crash() NORETURN;
     static int reap(Process&) WARN_UNUSED_RESULT;
@@ -331,6 +337,8 @@ private:
     Region* m_signal_stack_kernel_region { nullptr };
 
     RetainPtr<Region> m_display_framebuffer_region;
+
+    Vector<Window*> m_windows;
 };
 
 extern Process* current;

Kernel/ProcessGUI.cpp

@@ -0,0 +1,77 @@
+#include "Process.h"
+#include "MemoryManager.h"
+#include <LibC/errno_numbers.h>
+#include <Widgets/AbstractScreen.h>
+#include <Widgets/FrameBuffer.h>
+#include <Widgets/EventLoop.h>
+#include <Widgets/Font.h>
+#include <Widgets/Widget.h>
+#include <Widgets/Window.h>
+#include <Widgets/WindowManager.h>
+
+void Process::initialize_gui_statics()
+{
+    Font::initialize();
+    FrameBuffer::initialize();
+    EventLoop::initialize();
+    WindowManager::initialize();
+    AbstractScreen::initialize();
+
+    new EventLoop;
+}
+
+static void wait_for_gui_server()
+{
+    // FIXME: Time out after a while and return an error.
+    while (!EventLoop::main().running())
+        sleep(10);
+}
+
+int Process::gui$create_window(const GUI_CreateWindowParameters* user_params)
+{
+    wait_for_gui_server();
+
+    if (!validate_read_typed(user_params))
+        return -EFAULT;
+
+    GUI_CreateWindowParameters params = *user_params;
+    Rect rect { params.rect.x, params.rect.y, params.rect.width, params.rect.height };
+
+    if (rect.is_empty())
+        return -EINVAL;
+
+    ProcessPagingScope scope(EventLoop::main().server_process());
+
+    auto* window = new Window;
+    if (!window)
+        return -ENOMEM;
+
+    int window_id = m_windows.size();
+    m_windows.append(window);
+
+    window->setTitle(params.title);
+    window->setRect(rect);
+
+    auto* main_widget = new Widget;
+    window->setMainWidget(main_widget);
+    main_widget->setWindowRelativeRect({ 0, 0, rect.width(), rect.height() });
+    main_widget->setBackgroundColor(params.background_color);
+    main_widget->setFillWithBackgroundColor(true);
+    dbgprintf("%s<%u> gui$create_window: %d with rect {%d,%d %dx%d}\n", name().characters(), pid(), window_id, rect.x(), rect.y(), rect.width(), rect.height());
+
+    return window_id;
+}
+
+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);
+    window->deleteLater();
+    return 0;
+}

Kernel/Syscall.cpp

@@ -187,6 +187,10 @@ static dword handle(RegisterDump& regs, dword function, dword arg1, dword arg2,
         return current->sys$utime((const char*)arg1, (const Unix::utimbuf*)arg2);
     case Syscall::SC_sync:
         return sync();
+    case Syscall::SC_gui_create_window:
+        return current->gui$create_window((const GUI_CreateWindowParameters*)arg1);
+    case Syscall::SC_gui_destroy_window:
+        return current->gui$destroy_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

@@ -66,6 +66,8 @@
     __ENUMERATE_SYSCALL(times) \
     __ENUMERATE_SYSCALL(utime) \
     __ENUMERATE_SYSCALL(sync) \
+    __ENUMERATE_SYSCALL(gui_create_window) \
+    __ENUMERATE_SYSCALL(gui_destroy_window) \
 
 namespace Syscall {
 

Kernel/WindowComposer.cpp

@@ -14,18 +14,11 @@
 
 void WindowComposer_main()
 {
-    Font::initialize();
-    FrameBuffer::initialize();
-    EventLoop::initialize();
-    WindowManager::initialize();
-    AbstractScreen::initialize();
-
     auto info = current->get_display_info();
 
     dbgprintf("Screen is %ux%ux%ubpp\n", info.width, info.height, info.bpp);
 
     FrameBuffer framebuffer((dword*)info.framebuffer, info.width, info.height);
-    EventLoop loop;
 
     MsgBox(nullptr, "Serenity Operating System");
 
@@ -75,7 +68,7 @@ void WindowComposer_main()
     }
 
     dbgprintf("Entering WindowComposer main loop.\n");
-    loop.exec();
+    EventLoop::main().exec();
 
     ASSERT_NOT_REACHED();
 }

Kernel/init.cpp

@@ -22,6 +22,7 @@
 #include "Scheduler.h"
 #include "PS2MouseDevice.h"
 
+#define SPAWN_GUI_TEST_APP
 //#define SPAWN_MULTIPLE_SHELLS
 //#define STRESS_TEST_SPAWNING
 
@@ -94,6 +95,9 @@ static void init_stage2()
 
     int error;
     Process::create_user_process("/bin/sh", (uid_t)100, (gid_t)100, (pid_t)0, error, { }, move(environment), tty0);
+#ifdef SPAWN_GUI_TEST_APP
+    Process::create_user_process("/bin/guitest", (uid_t)100, (gid_t)100, (pid_t)0, error, { }, move(environment), tty0);
+#endif
 #ifdef SPAWN_MULTIPLE_SHELLS
     Process::create_user_process("/bin/sh", (uid_t)100, (gid_t)100, (pid_t)0, error, { }, { }, tty1);
     Process::create_user_process("/bin/sh", (uid_t)100, (gid_t)100, (pid_t)0, error, { }, { }, tty2);

Kernel/sync.sh

@@ -30,6 +30,7 @@ cp -v ../Userland/mkdir mnt/bin/mkdir
 cp -v ../Userland/touch mnt/bin/touch
 cp -v ../Userland/sync mnt/bin/sync
 cp -v ../Userland/more mnt/bin/more
+cp -v ../Userland/guitest mnt/bin/guitest
 sh sync-local.sh
 cp -v kernel.map mnt/
 ln -s dir_a mnt/dir_cur