From: Jaakko Salli <jaakko.salli@dnainternet.net>
Date: Fri, 18 Jun 2010 13:18:22 +0000 (+0000)
Subject: Use placement new when storing value in wxAnyValueBuffer. This should allow using... 
X-Git-Url: https://git.saurik.com/wxWidgets.git/commitdiff_plain/94cd7b004d3587fdec8f91dea7f770c58f4f84db?hp=854492623833a7070a435c3632cf156de952182c

Use placement new when storing value in wxAnyValueBuffer. This should allow using any data type, regardless whether it is Plain Old Data or copyable or not.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@64623 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
---

diff --git a/include/wx/any.h b/include/wx/any.h
index 366f4bc5e3..03453ead82 100644
--- a/include/wx/any.h
+++ b/include/wx/any.h
@@ -16,8 +16,8 @@
 
 #if wxUSE_ANY
 
+#include <new> // for placement new
 #include "wx/string.h"
-#include "wx/meta/pod.h"
 #include "wx/meta/if.h"
 #include "wx/typeinfo.h"
 
@@ -193,18 +193,24 @@ namespace wxPrivate
 {
 
 template<typename T>
-class wxAnyValueTypeOpsPOD
+class wxAnyValueTypeOpsInplace
 {
 public:
     static void DeleteValue(wxAnyValueBuffer& buf)
     {
-        wxUnusedVar(buf);
+        T* value = reinterpret_cast<T*>(&buf.m_buffer[0]);
+        value->~T();
+
+        // Some compiler may given 'unused variable' warnings without this
+        wxUnusedVar(value);
     }
 
     static void SetValue(const T& value,
                          wxAnyValueBuffer& buf)
     {
-        memcpy(buf.m_buffer, &value, sizeof(T));
+        // Use placement new
+        void* const place = buf.m_buffer;
+        ::new(place) T(value);
     }
 
     static const T& GetValue(const wxAnyValueBuffer& buf)
@@ -270,9 +276,8 @@ public:
 template<typename T>
 class wxAnyValueTypeImplBase : public wxAnyValueType
 {
-    typedef typename wxIf< wxIsPod<T>::value &&
-                                sizeof(T) <= WX_ANY_VALUE_BUFFER_SIZE,
-                           wxPrivate::wxAnyValueTypeOpsPOD<T>,
+    typedef typename wxIf< sizeof(T) <= WX_ANY_VALUE_BUFFER_SIZE,
+                           wxPrivate::wxAnyValueTypeOpsInplace<T>,
                            wxPrivate::wxAnyValueTypeOpsGeneric<T> >::value
             Ops;
 
diff --git a/interface/wx/any.h b/interface/wx/any.h
index b7e1fe0725..47cc6fb6cd 100644
--- a/interface/wx/any.h
+++ b/interface/wx/any.h
@@ -45,27 +45,8 @@
 
     When compared to wxVariant, there are various internal implementation
     differences as well. For instance, wxAny only allocates separate data
-    object in heap for large (i.e. size in bytes more than
-    WX_ANY_VALUE_BUFFER_SIZE) or non-POD (Plain Old Data) data types.
-    Pointers, integers, bools etc. are fitted in the wxAny's internal buffer
-    without need for any extra allocation. It is possible that wxAny cannot
-    automatically determine if your own data structure is considered a
-    POD or not, so you may need to declare it as such explicitly, using
-    code like this:
-
-    @code
-    #include "wx/meta/pod.h"
-    WX_DECLARE_TYPE_POD(MyPodStruct)
-    @endcode
-
-    Be extra careful what you declare as Plain Old Data. It must be such data
-    that can be copied with memcpy() without corrupting program integrity. For
-    instance, POD structures usually cannot contain pointers or references to
-    other data. wxRect, wxPoint, and wxSize are good examples of POD
-    classes.
-
-    Note that pointers to any and all types are already automatically
-    declared as Plain Old Data.
+    object in heap for large objects (i.e. ones with size more than
+    WX_ANY_VALUE_BUFFER_SIZE, which at the time of writing is 16 bytes).
 
     @library{wxbase}
     @category{data}