X-Git-Url: http://git.tdb.fi/?p=libs%2Fcore.git;a=blobdiff_plain;f=source%2Fcore%2Frefptr.h;h=79401dce5be40094a9f55212c0c3fb4abd8f7dc9;hp=8ab1b7cbfbdb6e752afd4b7634e807a8a836e10a;hb=HEAD;hpb=74e62aabadda67d02b3eab09baa37c9d7640b794

diff --git a/source/core/refptr.h b/source/core/refptr.h
index 8ab1b7c..1a164c1 100644
--- a/source/core/refptr.h
+++ b/source/core/refptr.h
@@ -10,11 +10,13 @@ struct RefCounts
 		KEEP = 1U<<(sizeof(unsigned)*8-1)
 	};
 
-	unsigned count;
-
-	RefCounts(): count(0) { }
+	unsigned count = 0;
+	unsigned weak_count = 0;
 };
 
+template<typename T>
+class WeakPtr;
+
 
 /**
 A reference counting smart pointer.  When the last RefPtr for the data gets
@@ -24,16 +26,17 @@ template<typename T>
 class RefPtr
 {
 	template<typename U> friend class RefPtr;
+	template<typename U> friend class WeakPtr;
 
 private:
-	T *data;
-	RefCounts *counts;
+	T *data = nullptr;
+	RefCounts *counts = nullptr;
 
 public:
-	RefPtr(): data(0), counts(0) { }
-	RefPtr(T *d): data(d), counts(data ? new RefCounts : 0) { incref(); }
+	RefPtr() = default;
+	RefPtr(T *d): data(d), counts(data ? new RefCounts : nullptr) { incref(); }
 private:
-	RefPtr(T *d, RefCounts *c): data(d), counts(d ? c : 0) { incref(); }
+	RefPtr(T *d, RefCounts *c): data(d), counts(d ? c : nullptr) { incref(); }
 
 public:
 	/* Must have this or the compiler will generate a default copy-c'tor despite
@@ -43,16 +46,12 @@ public:
 	template<typename U>
 	RefPtr(const RefPtr<U> &p): data(p.data), counts(p.counts) { incref(); }
 
+	template<typename U>
+	RefPtr(const WeakPtr<U> &p): data(p.get()), counts(data ? p.counts : nullptr) { incref(); }
+
 	~RefPtr() { decref(); }
 
-	RefPtr &operator=(T *d)
-	{
-		decref();
-		data = d;
-		counts = (d ? new RefCounts : 0);
-		incref();
-		return *this;
-	}
+	RefPtr &operator=(T *);
 
 	// Likewise for the assignment operator
 	RefPtr &operator=(const RefPtr &p) { return assign(p); }
@@ -60,42 +59,27 @@ public:
 	template<typename U>
 	RefPtr &operator=(const RefPtr<U> &p) { return assign(p); }
 
+	template<typename U>
+	RefPtr &operator=(const WeakPtr<U> &p) { return assign(RefPtr(p)); }
+
 private:
 	template<typename U>
-	RefPtr &assign(const RefPtr<U> &p)
-	{
-		decref();
-		data = p.data;
-		counts = p.counts;
-		incref();
-		return *this;
-	}
+	RefPtr &assign(const RefPtr<U> &);
 
 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();
-		counts = 0;
-		return d;
-	}
+	T *release();
 
 	/** Marks the data to not be deleted.  This affects all RefPtrs with the
 	same data. */
-	void keep()
-	{
-		if(counts)
-			counts->count |= RefCounts::KEEP;
-	}
+	void keep() { if(counts) counts->count |= RefCounts::KEEP; }
 
 	T *get() const { return data; }
 	T &operator*() const { return *data; }
 	T *operator->() const { return data; }
-	operator bool() const { return data!=0; }
+	explicit operator bool() const { return data; }
 
 	unsigned refcount() const { return (data ? counts->count : 0); }
 
@@ -104,31 +88,136 @@ public:
 	{ return RefPtr<T>(dynamic_cast<T *>(p.data), p.counts); }
 
 private:
-	void incref()
+	void incref() { if(counts) ++counts->count; }
+	void decref();
+};
+
+
+template<typename T>
+class WeakPtr
+{
+	template<typename U> friend class RefPtr;
+	template<typename U> friend class WeakPtr;
+
+private:
+	T *data = nullptr;
+	RefCounts *counts = nullptr;
+
+public:
+	WeakPtr() = default;
+private:
+	WeakPtr(T *d, RefCounts *c): data(d), counts(d ? c : nullptr) { incref(); }
+
+public:
+	WeakPtr(const WeakPtr &p): data(p.get()), counts(data ? p.counts : nullptr) { incref(); }
+
+	template<typename U>
+	WeakPtr(const WeakPtr<U> &p): data(p.get()), counts(data ? p.counts : nullptr) { incref(); }
+
+	template<typename U>
+	WeakPtr(const RefPtr<U> &p): data(p.data), counts(p.counts) { incref(); }
+
+	WeakPtr &operator=(const WeakPtr &p) { return assign(p); }
+
+	template<typename U>
+	WeakPtr &operator=(const WeakPtr<U> &p) { return assign(p); }
+
+	template<typename U>
+	WeakPtr &operator=(const RefPtr<U> &p) { return assign(WeakPtr(p)); }
+
+private:
+	template<typename U>
+	WeakPtr &assign(const WeakPtr<U> &);
+
+	T *get() const { return (counts && counts->count ? data : nullptr); }
+	void incref() { if(counts) ++counts->weak_count; }
+	void decref();
+};
+
+
+template<typename T>
+RefPtr<T> &RefPtr<T>::operator=(T *d)
+{
+	decref();
+	data = d;
+	counts = (d ? new RefCounts : nullptr);
+	incref();
+	return *this;
+}
+
+template<typename T>
+template<typename U>
+RefPtr<T> &RefPtr<T>::assign(const RefPtr<U> &p)
+{
+	if(static_cast<const void *>(&p)==this)
+		return *this;
+
+	decref();
+	data = p.data;
+	counts = p.counts;
+	incref();
+	return *this;
+}
+
+template<typename T>
+T *RefPtr<T>::release()
+{
+	T *d = data;
+	data = nullptr;
+	decref();
+	counts = nullptr;
+	return d;
+}
+
+template<typename T>
+void RefPtr<T>::decref()
+{
+	if(!counts) return;
+	--counts->count;
+	if(!counts->count)
 	{
-		if(!counts) return;
-		++counts->count;
+		delete data;
+		data = nullptr;
 	}
+	else if(counts->count==RefCounts::KEEP)
+		data = nullptr;
+	else
+		return;
 
-	void decref()
+	if(!counts->weak_count)
 	{
-		if(!counts) return;
-		--counts->count;
-		if(!counts->count)
-		{
-			delete data;
-			delete counts;
-			data = 0;
-			counts = 0;
-		}
-		else if(counts->count==RefCounts::KEEP)
-		{
-			delete counts;
-			data = 0;
-			counts = 0;
-		}
+		delete counts;
+		counts = nullptr;
 	}
-};
+}
+
+
+template<typename T>
+template<typename U>
+WeakPtr<T> &WeakPtr<T>::assign(const WeakPtr<U> &p)
+{
+	if(&p==this)
+		return *this;
+
+	decref();
+	data = p.get();
+	counts = (data ? p.counts : nullptr);
+	incref();
+	return *this;
+}
+
+template<typename T>
+void WeakPtr<T>::decref()
+{
+	if(!counts) return;
+	--counts->weak_count;
+	if(!counts->weak_count && (!counts->count || counts->count==RefCounts::KEEP))
+	{
+		delete counts;
+		data = nullptr;
+		counts = nullptr;
+	}
+}
 
 } // namespace Msp