X-Git-Url: http://git.tdb.fi/?p=libs%2Fcore.git;a=blobdiff_plain;f=source%2Fcore%2Frefptr.h;h=d245b34a7e90bab8fb14f5e26cc691a1385f761c;hp=ee020e0eb8783f3af6579f8960b4ae1707b9b18d;hb=967785734be5c3fc6f75da122c2d93ebbb338271;hpb=521cf1db00f8ce2d9f9494dca503d6c17d89ac2f

diff --git a/source/core/refptr.h b/source/core/refptr.h
index ee020e0..d245b34 100644
--- a/source/core/refptr.h
+++ b/source/core/refptr.h
@@ -1,53 +1,105 @@
-/* $Id$
-
-This file is part of libmspcore
-Copyright © 2006-2007 Mikko Rasa, Mikkosoft Productions
-Distributed under the LGPL
-*/
 #ifndef MSP_CORE_REFPTR_H_
 #define MSP_CORE_REFPTR_H_
 
 namespace Msp {
 
+/**
+A reference counting smart pointer.  When the last RefPtr for the data gets
+destroyed, the data is deleted as well.
+*/
 template<typename T>
 class RefPtr
 {
+	template<typename U> friend class RefPtr;
+
+private:
+	enum
+	{
+		KEEP = 1U<<(sizeof(unsigned)*8-1)
+	};
+
+	T *data;
+	unsigned *count;
+
 public:
 	RefPtr(): data(0), count(0) { }
-	RefPtr(T *d): data(d), count(0) { if(data) count=new unsigned(1); }
+	RefPtr(T *d): data(d), count(data ? new unsigned(1) : 0) { }
+private:
+	RefPtr(T *d, unsigned *c): data(d), count(d ? c : 0) { incref(); }
+
+public:
+	/* Must have this or the compiler will generate a default copy-c'tor despite
+	the template version */
 	RefPtr(const RefPtr &p): data(p.data), count(p.count) { incref(); }
+
+	template<typename U>
+	RefPtr(const RefPtr<U> &p): data(p.data), count(p.count) { incref(); }
+
 	~RefPtr() { decref(); }
 
-	RefPtr &operator=(const RefPtr &p)
+	RefPtr &operator=(T *d)
+	{
+		decref();
+		data = d;
+		count = (d ? new unsigned(1) : 0);
+		return *this;
+	}
+
+	// Likewise for the assignment operator
+	RefPtr &operator=(const RefPtr &p) { return assign(p); }
+
+	template<typename U>
+	RefPtr &operator=(const RefPtr<U> &p) { return assign(p); }
+
+private:
+	template<typename U>
+	RefPtr &assign(const RefPtr<U> &p)
 	{
 		decref();
-		data=p.data;
-		count=p.count;
+		data = p.data;
+		count = p.count;
 		incref();
 		return *this;
 	}
 
-	T *get() const        { return data; }
-	T &operator*() const  { return *data; }
+public:
+	/** Makes the RefPtr release its reference of the data without deleting it.
+	Note that if there are other RefPtrs left with the same data, it might
+	still get deleted automatically. */
+	T *release()
+	{
+		T *d = data;
+		data = 0;
+		decref();
+		count = 0;
+		return d;
+	}
+
+	/** Marks the data to not be deleted.  This affects all RefPtrs with the
+	same data. */
+	void keep()
+	{
+		if(count)
+			*count |= KEEP;
+	}
+
+	T *get() const { return data; }
+	T &operator*() const { return *data; }
 	T *operator->() const { return data; }
 	operator bool() const { return data!=0; }
 
 	template<typename U>
-	static RefPtr<T> cast_dynamic(const RefPtr<U> &p)  { return RefPtr<T>(dynamic_cast<T *>(p.get()), p.count); }
-	template<typename U> friend class RefPtr;
-private:
-	T        *data;
-	unsigned *count;
+	static RefPtr<T> cast_dynamic(const RefPtr<U> &p)
+	{ return RefPtr<T>(dynamic_cast<T *>(p.data), p.count); }
 
-	RefPtr(T *d, unsigned *c): data(d), count(c) { incref(); }
-
-	void  incref()
+private:
+	void incref()
 	{
 		if(!count) return;
 		++*count;
 	}
 
-	void  decref()
+	void decref()
 	{
 		if(!count) return;
 		--*count;
@@ -55,8 +107,14 @@ private:
 		{
 			delete data;
 			delete count;
-			data=0;
-			count=0;
+			data = 0;
+			count = 0;
+		}
+		else if(*count==KEEP)
+		{
+			delete count;
+			data = 0;
+			count = 0;
 		}
 	}
 };