From edd806fc74e5f58c73ab79e5fd63a6da14458344 Mon Sep 17 00:00:00 2001
From: Jonas 'Sortie' Termansen <sortie@maxsi.org>
Date: Tue, 21 Feb 2012 20:12:52 +0100
Subject: [PATCH] Added a Refcounted class, useful for refcounted objects.

---
 sortix/Makefile     |  1 +
 sortix/refcount.cpp | 52 +++++++++++++++++++++++++++++++++++++++++++++
 sortix/refcount.h   | 47 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 100 insertions(+)
 create mode 100644 sortix/refcount.cpp
 create mode 100644 sortix/refcount.h

diff --git a/sortix/Makefile b/sortix/Makefile
index fc80dc0f..e4dea8d9 100644
--- a/sortix/Makefile
+++ b/sortix/Makefile
@@ -95,6 +95,7 @@ vgaterminal.o \
 serialterminal.o \
 descriptors.o \
 device.o \
+refcount.o \
 vga.o \
 elf.o \
 process.o \
diff --git a/sortix/refcount.cpp b/sortix/refcount.cpp
new file mode 100644
index 00000000..29cecd43
--- /dev/null
+++ b/sortix/refcount.cpp
@@ -0,0 +1,52 @@
+/*******************************************************************************
+
+	COPYRIGHT(C) JONAS 'SORTIE' TERMANSEN 2012.
+
+	This file is part of Sortix.
+
+	Sortix is free software: you can redistribute it and/or modify it under the
+	terms of the GNU General Public License as published by the Free Software
+	Foundation, either version 3 of the License, or (at your option) any later
+	version.
+
+	Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
+	WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+	FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+	details.
+
+	You should have received a copy of the GNU General Public License along with
+	Sortix. If not, see <http://www.gnu.org/licenses/>.
+
+	refcount.cpp
+	A class that implements reference counting.
+
+*******************************************************************************/
+
+#include "platform.h"
+#include "refcount.h"
+
+namespace Sortix
+{
+	Refcounted::Refcounted()
+	{
+		refcount = 1;
+	}
+
+	Refcounted::~Refcounted()
+	{
+		// It's OK to be deleted if our refcount is 1, it won't mess with any
+		// other owners that might need us.
+		ASSERT(refcount <= 1);
+	}
+
+	void Refcounted::Refer()
+	{
+		refcount++;
+	}
+
+	void Refcounted::Unref()
+	{
+		if ( !--refcount ) { delete this; }
+	}
+}
+
diff --git a/sortix/refcount.h b/sortix/refcount.h
new file mode 100644
index 00000000..9ceb79c6
--- /dev/null
+++ b/sortix/refcount.h
@@ -0,0 +1,47 @@
+/*******************************************************************************
+
+	COPYRIGHT(C) JONAS 'SORTIE' TERMANSEN 2012.
+
+	This file is part of Sortix.
+
+	Sortix is free software: you can redistribute it and/or modify it under the
+	terms of the GNU General Public License as published by the Free Software
+	Foundation, either version 3 of the License, or (at your option) any later
+	version.
+
+	Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
+	WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+	FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+	details.
+
+	You should have received a copy of the GNU General Public License along with
+	Sortix. If not, see <http://www.gnu.org/licenses/>.
+
+	refcount.h
+	A class that implements reference counting.
+
+*******************************************************************************/
+
+#ifndef SORTIX_REFCOUNT_H
+#define SORTIX_REFCOUNT_H
+
+namespace Sortix
+{
+	class Refcounted
+	{
+	public:
+		Refcounted();
+		~Refcounted();
+
+	public:
+		void Refer();
+		void Unref();
+
+	private:
+		size_t refcount;
+
+	};
+}
+
+#endif
+