LibCore: Add a forward declaration header

This patch adds <LibCore/Forward.h> and uses it in various places to
shrink the header dependency graph.

Author: awesomekling

AK/Forward.h

@@ -70,6 +70,9 @@ class NonnullRefPtr;
 template<typename T>
 class NonnullOwnPtr;
 
+template<typename T>
+class Optional;
+
 template<typename T>
 class RefPtr;
 
@@ -98,6 +101,7 @@ using AK::JsonObject;
 using AK::JsonValue;
 using AK::NonnullOwnPtr;
 using AK::NonnullRefPtr;
+using AK::Optional;
 using AK::OwnPtr;
 using AK::RefPtr;
 using AK::SinglyLinkedList;

AK/IntrusiveList.h

@@ -26,6 +26,8 @@
 
 #pragma once
 
+#include <AK/Assertions.h>
+
 namespace AK {
 
 class IntrusiveListNode;

AK/Optional.h

@@ -30,6 +30,8 @@
 #include <AK/Platform.h>
 #include <AK/StdLibExtras.h>
 
+namespace AK {
+
 template<typename T>
 class CONSUMABLE(unknown) alignas(T) Optional {
 public:
@@ -161,3 +163,7 @@ class CONSUMABLE(unknown) alignas(T) Optional {
     char m_storage[sizeof(T)];
     bool m_has_value { false };
 };
+
+}
+
+using AK::Optional;

Applications/Help/main.cpp

@@ -26,6 +26,7 @@
 
 #include "History.h"
 #include "ManualModel.h"
+#include <AK/ByteBuffer.h>
 #include <LibCore/File.h>
 #include <LibGUI/AboutDialog.h>
 #include <LibGUI/Action.h>

Applications/SystemMonitor/ProcessStacksWidget.cpp

@@ -25,6 +25,7 @@
  */
 
 #include "ProcessStacksWidget.h"
+#include <AK/ByteBuffer.h>
 #include <LibCore/File.h>
 #include <LibCore/Timer.h>
 #include <LibGUI/BoxLayout.h>

DevTools/HackStudio/Editor.cpp

@@ -26,6 +26,7 @@
 
 #include "Editor.h"
 #include "EditorWrapper.h"
+#include <AK/ByteBuffer.h>
 #include <AK/FileSystemPath.h>
 #include <LibCore/DirIterator.h>
 #include <LibCore/File.h>

DevTools/IPCCompiler/main.cpp

@@ -25,6 +25,7 @@
  */
 
 #include <AK/BufferStream.h>
+#include <AK/Function.h>
 #include <AK/HashMap.h>
 #include <AK/StringBuilder.h>
 #include <LibCore/File.h>

Libraries/LibAudio/WavLoader.cpp

@@ -25,6 +25,7 @@
  */
 
 #include <AK/BufferStream.h>
+#include <AK/OwnPtr.h>
 #include <LibAudio/WavLoader.h>
 #include <LibCore/File.h>
 #include <LibCore/IODeviceStreamReader.h>

Libraries/LibCore/Event.h

@@ -30,11 +30,10 @@
 #include <AK/String.h>
 #include <AK/Types.h>
 #include <AK/WeakPtr.h>
+#include <LibCore/Forward.h>
 
 namespace Core {
 
-class Object;
-
 class Event {
 public:
     enum Type {

Libraries/LibCore/EventLoop.cpp

@@ -24,12 +24,14 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include <AK/Badge.h>
 #include <AK/IDAllocator.h>
 #include <AK/JsonObject.h>
 #include <AK/JsonValue.h>
 #include <AK/Time.h>
 #include <LibCore/Event.h>
 #include <LibCore/EventLoop.h>
+#include <LibCore/LocalServer.h>
 #include <LibCore/LocalSocket.h>
 #include <LibCore/Notifier.h>
 #include <LibCore/Object.h>
@@ -328,7 +330,7 @@ void EventLoop::post_event(Object& receiver, NonnullOwnPtr<Event>&& event)
 #ifdef CEVENTLOOP_DEBUG
     dbg() << "Core::EventLoop::post_event: {" << m_queued_events.size() << "} << receiver=" << receiver << ", event=" << event;
 #endif
-    m_queued_events.append({ receiver.make_weak_ptr(), move(event) });
+    m_queued_events.empend(receiver, move(event));
 }
 
 void EventLoop::wait_for_event(WaitMode mode)
@@ -509,4 +511,20 @@ void EventLoop::wake()
     }
 }
 
+EventLoop::QueuedEvent::QueuedEvent(Object& receiver, NonnullOwnPtr<Event> event)
+    : receiver(receiver.make_weak_ptr())
+    , event(move(event))
+{
+}
+
+EventLoop::QueuedEvent::QueuedEvent(QueuedEvent&& other)
+    : receiver(other.receiver)
+    , event(move(other.event))
+{
+}
+
+EventLoop::QueuedEvent::~QueuedEvent()
+{
+}
+
 }