LibCore: Introduce a C_OBJECT macro.

This macro goes at the top of every CObject-derived class like so:

class SomeClass : public CObject {
    C_OBJECT(SomeClass)
public:
    ...

At the moment, all it does is create an override for the class_name() getter
but in the future this will be used to automatically insert member functions
into these classes.

Libraries/LibCore/CFile.h

@@ -4,6 +4,7 @@
 #include <LibCore/CIODevice.h>
 
 class CFile final : public CIODevice {
+    C_OBJECT(CFile)
 public:
     CFile() {}
     explicit CFile(const StringView&);
@@ -20,8 +21,6 @@ public:
     };
     bool open(int fd, CIODevice::OpenMode, ShouldCloseFileDescription);
 
-    virtual const char* class_name() const override { return "CFile"; }
-
 private:
     String m_filename;
     ShouldCloseFileDescription m_should_close_file_descriptor { ShouldCloseFileDescription::Yes };

Libraries/LibCore/CHttpJob.h

@@ -7,14 +7,13 @@
 class CTCPSocket;
 
 class CHttpJob final : public CNetworkJob {
+    C_OBJECT(CHttpJob)
 public:
     explicit CHttpJob(const CHttpRequest&);
     virtual ~CHttpJob() override;
 
     virtual void start() override;
 
-    virtual const char* class_name() const override { return "CHttpJob"; }
-
 private:
     void on_socket_connected();
 

Libraries/LibCore/CIODevice.h

@@ -5,6 +5,7 @@
 #include <LibCore/CObject.h>
 
 class CIODevice : public CObject {
+    C_OBJECT(CIODevice)
 public:
     enum OpenMode {
         NotOpen = 0,
@@ -52,8 +53,6 @@ public:
 
     int printf(const char*, ...);
 
-    virtual const char* class_name() const override { return "CIODevice"; }
-
 protected:
     explicit CIODevice(CObject* parent = nullptr);
 

Libraries/LibCore/CLocalSocket.h

@@ -2,6 +2,7 @@
 #include <LibCore/CSocket.h>
 
 class CLocalSocket final : public CSocket {
+    C_OBJECT(CLocalSocket)
 public:
     explicit CLocalSocket(CObject* parent = nullptr);
     virtual ~CLocalSocket() override;

Libraries/LibCore/CNetworkJob.h

@@ -6,6 +6,7 @@
 class CNetworkResponse;
 
 class CNetworkJob : public CObject {
+    C_OBJECT(CNetworkJob)
 public:
     enum class Error {
         None,
@@ -24,8 +25,6 @@ public:
 
     virtual void start() = 0;
 
-    virtual const char* class_name() const override { return "CNetworkJob"; }
-
 protected:
     CNetworkJob();
     void did_finish(NonnullRefPtr<CNetworkResponse>&&);

Libraries/LibCore/CNotifier.h

@@ -4,6 +4,7 @@
 #include "CObject.h"
 
 class CNotifier : public CObject {
+    C_OBJECT(CNotifier)
 public:
     enum Event {
         None = 0,
@@ -12,7 +13,7 @@ public:
         Exceptional = 4,
     };
     CNotifier(int fd, unsigned event_mask);
-    ~CNotifier();
+    virtual ~CNotifier() override;
 
     void set_enabled(bool);
 
@@ -23,8 +24,7 @@ public:
     unsigned event_mask() const { return m_event_mask; }
     void set_event_mask(unsigned event_mask) { m_event_mask = event_mask; }
 
-    const char* class_name() const override { return "CNotifier"; }
-    void event(CEvent& event) override;
+    void event(CEvent&) override;
 
 private:
     int m_fd { -1 };

Libraries/LibCore/CObject.h

@@ -11,13 +11,16 @@ class CChildEvent;
 class CCustomEvent;
 class CTimerEvent;
 
+#define C_OBJECT(klass) \
+public:                 \
+    virtual const char* class_name() const override { return #klass; }
+
 class CObject : public Weakable<CObject> {
+    // NOTE: No C_OBJECT macro for CObject itself.
 public:
-    CObject(CObject* parent = nullptr, bool is_widget = false);
     virtual ~CObject();
 
-    virtual const char* class_name() const { return "CObject"; }
-
+    virtual const char* class_name() const = 0;
     virtual void event(CEvent&);
 
     const String& name() const { return m_name; }
@@ -58,6 +61,8 @@ public:
     virtual bool is_window() const { return false; }
 
 protected:
+    CObject(CObject* parent = nullptr, bool is_widget = false);
+
     virtual void timer_event(CTimerEvent&);
     virtual void child_event(CChildEvent&);
     virtual void custom_event(CCustomEvent&);

Libraries/LibCore/CSocket.h

@@ -6,6 +6,7 @@
 class CNotifier;
 
 class CSocket : public CIODevice {
+    C_OBJECT(CSocket)
 public:
     enum class Type {
         Invalid,
@@ -35,8 +36,6 @@ public:
 
     Function<void()> on_connected;
 
-    virtual const char* class_name() const override { return "CSocket"; }
-
 protected:
     CSocket(Type, CObject* parent);
 

Libraries/LibCore/CTCPSocket.h

@@ -1,6 +1,7 @@
 #include <LibCore/CSocket.h>
 
 class CTCPSocket final : public CSocket {
+    C_OBJECT(CTCPSocket)
 public:
     explicit CTCPSocket(CObject* parent = nullptr);
     virtual ~CTCPSocket() override;

Libraries/LibCore/CTimer.h

@@ -4,6 +4,7 @@
 #include <LibCore/CObject.h>
 
 class CTimer final : public CObject {
+    C_OBJECT(CTimer)
 public:
     explicit CTimer(CObject* parent = nullptr);
     CTimer(int interval, Function<void()>&& timeout_handler, CObject* parent = nullptr);
@@ -29,8 +30,6 @@ public:
 
     Function<void()> on_timeout;
 
-    virtual const char* class_name() const override { return "CTimer"; }
-
 private:
     virtual void timer_event(CTimerEvent&) override;
 

Libraries/LibCore/CoreIPCClient.h

@@ -49,6 +49,7 @@ private:
 
 template <typename ServerMessage, typename ClientMessage>
 class Connection : public CObject {
+    C_OBJECT(Connection)
 public:
     Connection(const StringView& address)
         : m_notifier(CNotifier(m_connection.fd(), CNotifier::Read))

Libraries/LibCore/CoreIPCServer.h

@@ -55,8 +55,8 @@ T* new_connection_for_client(Args&& ... args)
 };
 
 template <typename ServerMessage, typename ClientMessage>
-class Connection : public CObject
-{
+class Connection : public CObject {
+    C_OBJECT(Connection)
 public:
     Connection(int fd, int client_id)
         : m_socket(fd)
@@ -168,8 +168,6 @@ public:
         m_notifier.set_enabled(false);
     }
 
-    const char* class_name() const override { return "Connection"; }
-
     int client_id() const { return m_client_id; }
     pid_t client_pid() const { return m_pid; }
     void set_client_pid(pid_t pid) { m_pid = pid; }
@@ -194,10 +192,9 @@ protected:
 
 private:
     // TODO: A way to create some kind of CIODevice with an open FD would be nice.
-    class COpenedSocket : public CIODevice
-    {
+    class COpenedSocket : public CIODevice {
+        C_OBJECT(COpenedSocket)
     public:
-        const char* class_name() const override { return "COpenedSocket"; }
         COpenedSocket(int fd)
         {
             set_fd(fd);