Add initial pass of syscall API kobjects

src/kernel/objects/kobject.h

@@ -0,0 +1,110 @@
+#pragma once
+/// \file kobject.h
+/// Definition of base type for user-interactable kernel objects
+
+#include "j6/errors.h"
+#include "j6/types.h"
+#include "kutil/vector.h"
+
+/// Base type for all user-interactable kernel objects
+class kobject
+{
+public:
+	/// Types of kernel objects.
+	enum class type : uint16_t
+	{
+		none,
+
+		event,
+		eventpair,
+
+		vms,
+		vmo,
+
+		job,
+		process,
+		thread,
+	};
+
+	kobject(type t, j6_signal_t signals = 0ull);
+	virtual ~kobject();
+
+	/// Generate a new koid for a given type
+	/// \arg t    The object type
+	/// \returns  A new unique koid
+	static j6_koid_t koid_generate(type t);
+
+	/// Get the kobject type from a given koid
+	/// \arg koid  An existing koid
+	/// \returns   The object type for the koid
+	static type koid_type(j6_koid_t koid);
+
+	/// Set the given signals active on this object
+	/// \arg s  The set of signals to assert
+	void assert_signal(j6_signal_t s);
+
+	/// Clear the given signals on this object
+	/// \arg s  The set of signals to deassert
+	void deassert_signal(j6_signal_t s);
+
+	class observer
+	{
+	public:
+		/// Callback for when signals change.
+		/// \arg obj     The object triggering the callback
+		/// \arg s       The current state of obj's signals
+		/// \arg ds      Which signals caused the callback
+		/// \arg result  Status code for this notification
+		/// \returns     True if this object wants to keep watching signals
+		virtual bool on_signals_changed(
+				kobject *obj,
+				j6_signal_t s,
+				j6_signal_t ds,
+				j6_status_t result) = 0;
+	};
+
+	/// Register a signal observer
+	/// \arg object  The observer
+	/// \arg s       The signals the object wants notifiations for
+	void register_signal_observer(observer *object, j6_signal_t s);
+
+	/// Deegister a signal observer
+	/// \arg object  The observer
+	void deregister_signal_observer(observer *object);
+
+	/// Increment the handle refcount
+	inline void handle_retain() { ++m_handle_count; }
+
+	/// Decrement the handle refcount
+	inline void handle_release() {
+		if (--m_handle_count == 0) on_no_handles();
+	}
+
+protected:
+	kobject() = delete;
+	kobject(const kobject &other) = delete;
+	kobject(const kobject &&other) = delete;
+
+	/// Notifiy observers of this object
+	/// \arg mask    The signals that triggered this call. If 0, notify all observers.
+	/// \arg result  The result to pass to the observers
+	void notify_signal_observers(j6_signal_t mask, j6_status_t result = j6_status_ok);
+
+	/// Interface for subclasses to handle when all handles are closed. Subclasses
+	/// should either call the base version, or assert j6_signal_no_handles.
+	virtual void on_no_handles();
+
+	j6_koid_t m_koid;
+	j6_signal_t m_signals;
+	uint16_t m_handle_count;
+
+	struct observer_registration
+	{
+		observer_registration(observer* o = nullptr, j6_signal_t s = 0) :
+			object(o), signals(s) {}
+
+		observer *object;
+		j6_signal_t signals;
+	};
+	kutil::vector<observer_registration> m_observers;
+};