Destroy all remaining windows in a process when it dies.

Kernel/Process.cpp

@@ -1490,9 +1490,10 @@ int Process::reap(Process& process)
 
     if (process.ppid()) {
         auto* parent = Process::from_pid(process.ppid());
-        ASSERT(parent);
+        if (parent) {
-        parent->m_ticks_in_user_for_dead_children += process.m_ticks_in_user + process.m_ticks_in_user_for_dead_children;
+            parent->m_ticks_in_user_for_dead_children += process.m_ticks_in_user + process.m_ticks_in_user_for_dead_children;
-        parent->m_ticks_in_kernel_for_dead_children += process.m_ticks_in_kernel + process.m_ticks_in_kernel_for_dead_children;
+            parent->m_ticks_in_kernel_for_dead_children += process.m_ticks_in_kernel + process.m_ticks_in_kernel_for_dead_children;
+        }
     }
 
     dbgprintf("reap: %s(%u) {%s}\n", process.name().characters(), process.pid(), toString(process.state()));
@@ -2143,4 +2144,5 @@ void Process::die()
 {
     set_state(Dead);
     m_fds.clear();
+    destroy_all_windows();
 }

Kernel/Process.h

@@ -216,6 +216,7 @@ public:
     static void initialize();
     static void initialize_gui_statics();
     int make_window_id();
+    void destroy_all_windows();
 
     void crash() NORETURN;
     static int reap(Process&) WARN_UNUSED_RESULT;

Kernel/ProcessGUI.cpp

@@ -257,3 +257,12 @@ int Process::gui$set_global_cursor_tracking_enabled(int window_id, bool enabled)
     window.set_global_cursor_tracking_enabled(enabled);
     return 0;
 }
+
+void Process::destroy_all_windows()
+{
+    for (auto& it : m_windows) {
+        auto message = make<WSMessage>(WSMessage::WM_DestroyWindow);
+        WSMessageLoop::the().post_message(it.value.leakPtr(), move(message), true);
+    }
+    m_windows.clear();
+}

WindowServer/WSMessage.h

@@ -14,6 +14,7 @@ public:
         WM_SetWindowTitle,
         WM_SetWindowRect,
         WM_DeferredCompose,
+        WM_DestroyWindow,
         MouseMove,
         MouseDown,
         MouseUp,

WindowServer/WSMessageLoop.cpp

@@ -71,9 +71,15 @@ int WSMessageLoop::exec()
     }
 }
 
-void WSMessageLoop::post_message(WSMessageReceiver* receiver, OwnPtr<WSMessage>&& message)
+void WSMessageLoop::post_message(WSMessageReceiver* receiver, OwnPtr<WSMessage>&& message, bool unsafe)
 {
-    ASSERT_INTERRUPTS_ENABLED();
+    if (unsafe) {
+        // FIXME: This is such a hack. It should not exist.
+        m_queued_messages.append({ receiver, move(message) });
+        if (current != m_server_process)
+            m_server_process->request_wakeup();
+        return;
+    }
     LOCKER(m_lock);
 #ifdef WSEVENTLOOP_DEBUG
     dbgprintf("WSMessageLoop::post_message: {%u} << receiver=%p, message=%p\n", m_queued_messages.size(), receiver, message.ptr());

WindowServer/WSMessageLoop.h

@@ -15,7 +15,7 @@ public:
 
     int exec();
 
-    void post_message(WSMessageReceiver* receiver, OwnPtr<WSMessage>&&);
+    void post_message(WSMessageReceiver* receiver, OwnPtr<WSMessage>&&, bool unsafe = false);
 
     static WSMessageLoop& the();
 

WindowServer/WSWindow.cpp

@@ -107,12 +107,17 @@ void WSWindow::on_message(WSMessage& message)
     case WSMessage::WM_SetWindowTitle:
         set_title(static_cast<WSSetWindowTitleMessage&>(message).title());
         return;
+    case WSMessage::WM_DestroyWindow:
+        delete this;
+        return;
     case WSMessage::WindowActivated:
         gui_event.type = GUI_Event::Type::WindowActivated;
         break;
     case WSMessage::WindowDeactivated:
         gui_event.type = GUI_Event::Type::WindowDeactivated;
         break;
+    default:
+        break;
     }
 
     if (gui_event.type == GUI_Event::Type::Invalid)