Re: bzr commit into mysql-trunk-bugfixing branch (martin.hansson:3260) Bug#58918

[Tor Didriksen]

On Tue, Dec 14, 2010 at 1:50 PM, Martin Hansson
<martin.hansson@stripped>wrote:

> #At file:///data0/martin/bzrroot/refactoring-Field_clone/n-mr-o-t/ based on
> revid:tor.didriksen@stripped
>
>  3260 Martin Hansson    2010-12-14
>      Bug#58918: Add a clone member function to the Field class for better
>      duplication
>
>      The patch removes all copying of Field objects using memcpy() and
> replaces it
>      with virtual clone() and clone(MEM_ROOT*) member functions that rely
> on the
>      copy constructor. An operator new (MEM_ROOT*) is also implemented. The
> sole
>      purpose of the Field::size_of() member function was to support the
> memcpy and
>      it is now removed.
>     @ sql/field.cc
>        Removal of memcpy() based duplication.
>     @ sql/field.h
>        New implementation of clone() member functions.
>        Removal of size_of() member functions
>     @ sql/item.cc
>        Removal of memcpy() based duplication.
> @@ -84,8 +79,12 @@ class Field
>   Field(const Item &);                         /* Prevent use of these */
>   void operator=(Field &);
>  public:
> +  /* To do: inherit Sql_alloc and get these for free */
>
>
Why not go all the way :-)
This works like a charm:

class Field : public Sql_alloc
{
  Field(const Item &);                /* Prevent use of these */
  void operator=(Field &);
public:
  uchar        *ptr;            // Position to field in record
...
...


-- didrik


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