Imported SharedPtr.h header file from Vaca library.

third_party/vaca/include/Vaca/SharedPtr.h

@@ -0,0 +1,160 @@
+// Vaca - Visual Application Components Abstraction
+// Copyright (c) 2005-2009 David Capello
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions
+// are met:
+//
+// * Redistributions of source code must retain the above copyright
+//   notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above copyright
+//   notice, this list of conditions and the following disclaimer in
+//   the documentation and/or other materials provided with the
+//   distribution.
+// * Neither the name of the author nor the names of its contributors
+//   may be used to endorse or promote products derived from this
+//   software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+// COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+// OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef VACA_SHAREDPTR_H
+#define VACA_SHAREDPTR_H
+
+#include "Vaca/base.h"
+#include "Vaca/Referenceable.h"
+
+namespace Vaca {
+
+/**
+   A pointer which maintains reference counting and
+   automatically deletes the pointed object when it is
+   no longer referenced.
+
+   What is a shared pointer? It is a class that wraps a pointer to a
+   dynamically allocated object. Various shared pointers can share
+   the same object counting references for that object. When the
+   last shared pointer is destroyed, the object is automatically
+   deleted.
+
+   The SharedPtr is mainly used to wrap classes that handle
+   graphics resources (like Brush, Pen, Image, Icon, etc.).
+
+   @tparam T Must be of Referenceable type, because Referenceable has
+	     the reference counter.
+*/
+template<class T>
+class SharedPtr
+{
+  T* m_ptr;
+
+public:
+
+  SharedPtr() {
+    m_ptr = NULL;
+  }
+
+  /*explicit*/ SharedPtr(T* ptr) {
+    m_ptr = ptr;
+    ref();
+  }
+
+  SharedPtr(const SharedPtr<T>& other) {
+    m_ptr = other.get();
+    ref();
+  }
+
+  template<class T2>
+  SharedPtr(const SharedPtr<T2>& other) {
+    m_ptr = static_cast<T*>(other.get());
+    ref();
+  }
+
+  virtual ~SharedPtr() {
+    unref();
+  }
+
+  void reset(T* ptr = NULL) {
+    if (m_ptr != ptr) {
+      unref();
+      m_ptr = ptr;
+      ref();
+    }
+  }
+
+  SharedPtr& operator=(const SharedPtr<T>& other) {
+    if (m_ptr != other.get()) {
+      unref();
+      m_ptr = other.get();
+      ref();
+    }
+    return *this;
+  }
+
+  template<class T2>
+  SharedPtr& operator=(const SharedPtr<T2>& other) {
+    if (m_ptr != static_cast<T*>(other.get())) {
+      unref();
+      m_ptr = static_cast<T*>(other.get());
+      ref();
+    }
+    return *this;
+  }
+
+  inline T* get() const { return m_ptr; }
+  inline T& operator*() const { return *m_ptr; }
+  inline T* operator->() const { return m_ptr; }
+  inline operator T*() const { return m_ptr; }
+
+private:
+
+  void ref() {
+    if (m_ptr)
+      ((Referenceable*)m_ptr)->ref();
+  }
+
+  void unref() {
+    if (m_ptr) {
+      if (((Referenceable*)m_ptr)->unref() == 0)
+	((Referenceable*)m_ptr)->destroy();
+      m_ptr = NULL;
+    }
+  }
+};
+
+/**
+   Compares if two shared-pointers points to the same place (object, memory address).
+
+   @see @ref SharedPtr
+*/
+template<class T>
+bool operator==(const SharedPtr<T>& ptr1, const SharedPtr<T>& ptr2)
+{
+  return ptr1.get() == ptr2.get();
+}
+
+/**
+   Compares if two shared-pointers points to different places (objects, memory addresses).
+
+   @see @ref SharedPtr
+*/
+template<class T>
+bool operator!=(const SharedPtr<T>& ptr1, const SharedPtr<T>& ptr2)
+{
+  return ptr1.get() != ptr2.get();
+}
+
+} // namespace Vaca
+
+#endif // VACA_SHAREDPTR_H