[vlc-devel] [PATCH] vlc_common: Add C++ memory management helpers

[Hugo Beauzée-Luyssen]

Those are coming from my medialibrary branch, but since I plan on using
them elsewhere at some point, might as well make them VLC wide
Those helpers won't accept void* so they can't directly wrap a malloc
call, but we could have additional wrapper that perform the
reinterpret_cast for the caller.
---
 include/vlc_common.h | 55 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/include/vlc_common.h b/include/vlc_common.h
index c88503c1a5..606f5fedf7 100644
--- a/include/vlc_common.h
+++ b/include/vlc_common.h
@@ -1170,6 +1170,61 @@ static inline char *xstrdup (const char *str)
     return ptr;
 }
 
+/******************************************************************************
+ * C++ memory management helpers
+ ******************************************************************************/
+
+#ifdef __cplusplus
+
+#include <memory>
+
+// Wraps a C pointer to be released with free.
+// ex: vlc_wrap_cptr( var_GetString( "foo" ) );
+template <typename T>
+static inline std::unique_ptr<T, void (*)(void*)> vlc_wrap_cptr( T* ptr ) noexcept
+{
+    return std::unique_ptr<T, decltype( &free )>( ptr, &free );
+}
+
+// Wraps a C array to be released with free.
+// This is necessary to allow the operator[] to be used
+template <typename T>
+static inline std::unique_ptr<T[], void (*)(void*)> vlc_wrap_carray( T* ptr ) noexcept
+{
+    return std::unique_ptr<T[], decltype( &free )>( ptr, &free );
+}
+
+// Wraps a pointer with a custom releaser
+// ex: auto ptr = vlc_wrap_cptr( input_item, &input_item_Release );
+template <typename T, typename Releaser>
+static inline auto vlc_wrap_cptr( T* ptr, Releaser&& r )
+    noexcept( noexcept( std::unique_ptr<T,
+                        typename std::decay<decltype( r )>::type> {
+                            ptr, std::forward<Releaser>( r )
+                        } ) )
+    -> std::unique_ptr<T, typename std::decay<decltype( r )>::type>
+{
+    return std::unique_ptr<T, typename std::decay<decltype( r )>::type>{
+                ptr, std::forward<Releaser>( r )
+    };
+}
+
+// Wraps a C array with a custom releaser
+template <typename T, typename Releaser>
+static inline auto vlc_wrap_carray( T* ptr, Releaser&& r )
+    noexcept( noexcept( std::unique_ptr<T[],
+                    typename std::decay<decltype( r )>::type> {
+                        ptr, std::forward<Releaser>( r )
+                    } ) )
+    -> std::unique_ptr<T[], typename std::decay<decltype( r )>::type>
+{
+    return std::unique_ptr<T[], typename std::decay<decltype( r )>::type>{
+        ptr, std::forward<Releaser>( r )
+    };
+}
+
+#endif
+
 /*****************************************************************************
  * libvlc features
  *****************************************************************************/
-- 
2.18.0