Make Dali::InstrusivePtr able to compare with nullptr

[platform/core/uifw/dali-core.git] / dali / public-api / common / intrusive-ptr.h

diff --git a/dali/public-api/common/intrusive-ptr.h b/dali/public-api/common/intrusive-ptr.h
index b566257..c962338 100644 (file)
--- a/dali/public-api/common/intrusive-ptr.h
+++ b/dali/public-api/common/intrusive-ptr.h
@@ -2,7 +2,7 @@
 #define DALI_INTRUSIVE_PTR_H
 
 /*
- * Copyright (c) 2020 Samsung Electronics Co., Ltd.
+ * Copyright (c) 2022 Samsung Electronics Co., Ltd.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,6 +18,9 @@
  *
  */
 
+// EXTERNAL INCLUDES
+#include <cstddef> // for std::nullptr_t
+
 // INTERNAL INCLUDES
 #include <dali/public-api/common/dali-common.h>
 
@@ -251,24 +254,17 @@ public:
     IntrusivePtr(rhs).Swap(*this);
   }
 
-  // IntrusivePtr comparisons - This is a variation of the safe bool idiom
-
-  /**
-   * @brief Pointer-to-member type.
-   *
-   * Objects can be implicitly converted to this for validity checks.
-   */
-  using BooleanType = void (IntrusivePtr<T>::*)() const;
+  // IntrusivePtr comparisons
 
   /**
-   * @brief Converts an object handle to a BooleanType.
+   * @brief Converts an object handle to a bool.
    *
    * This is useful for checking whether the handle is NULL.
    * @SINCE_1_0.0
    */
-  operator BooleanType() const
+  explicit operator bool() const
   {
-    return mPtr ? &IntrusivePtr::ThisIsSaferThanReturningVoidStar : nullptr;
+    return mPtr != nullptr;
   }
 
   /**
@@ -287,14 +283,6 @@ public:
 
 private:
   /**
-   * @brief Used by the safe bool idiom.
-   * @SINCE_1_0.0
-   */
-  void ThisIsSaferThanReturningVoidStar() const
-  {
-  }
-
-  /**
    * @brief Internal swap function.
    * @SINCE_1_0.0
    */
@@ -393,6 +381,62 @@ inline bool operator!=(T* lhs, IntrusivePtr<U> const& rhs)
 }
 
 /**
+ * @brief Comparison overrides of objects with nullptr_t.
+ *
+ * @SINCE_2_1.12
+ * @param[in] lhs Intrusive pointer to compare with
+ * @param[in] rhs nullptr
+ * @return True if the pointers is nullptr
+ */
+template<typename T>
+inline bool operator==(IntrusivePtr<T> const& lhs, std::nullptr_t rhs)
+{
+  return lhs.Get() == nullptr;
+}
+
+/**
+ * @brief Comparison overrides of objects with nullptr_t.
+ *
+ * @SINCE_2_1.12
+ * @param[in] lhs Intrusive pointer to compare with
+ * @param[in] rhs nullptr
+ * @return True if the pointers is not nullptr
+ */
+template<typename T>
+inline bool operator!=(IntrusivePtr<T> const& lhs, std::nullptr_t rhs)
+{
+  return lhs.Get() != nullptr;
+}
+
+/**
+ * @brief Comparison overrides of objects with nullptr_t.
+ *
+ * @SINCE_2_1.12
+ * @param[in] lhs nullptr
+ * @param[in] rhs Intrusive pointer to compare against
+ * @return True if the pointers is nullptr
+ */
+template<typename T>
+inline bool operator==(std::nullptr_t lhs, IntrusivePtr<T> const& rhs)
+{
+  return nullptr == rhs.Get();
+}
+
+/**
+ * @brief Comparison overrides of objects with nullptr_t.
+ *
+ * @SINCE_2_1.12
+ * @param[in] lhs nullptr
+ * @param[in] rhs Intrusive pointer to compare against
+ * @return True if the pointers is not nullptr
+ */
+template<typename T>
+inline bool operator!=(std::nullptr_t lhs, IntrusivePtr<T> const& rhs)
+{
+  return nullptr != rhs.Get();
+}
+
+/**
  * @}
  */
 } // namespace Dali