Re: [boost] [Block Pointer] Update

Subject: Re: [boost] [Block Pointer] Update
From: Phil Bouchard (philippeb8_at_[hidden])
Date: 2016-03-11 08:02:25

On 03/11/2016 01:31 AM, Gavin Lambert wrote:
> On 11/03/2016 16:50, Phil Bouchard wrote:
>
> I don't really understand the proxy thing, but I sense possible trouble
> in a single API name apparently creating different behaviour depending
> on the first parameter type, especially when the remaining parameters
> appear to be forwarded constructor parameters.  (What happens if you
> want to construct an object that takes a proxy as a parameter?)

The proxy ensures all sub allocations will be wiped out when it is 
destructed, cyclic or not.

> Perhaps the first call should be to a method make_root_block and the
> second two to one called make_child_block, or something along those lines?

I am fixing the pointer again and now the proxy will have to be fully 
explicit:

struct list {
public:
     list() : root(x) {}
     void clear() {
         root.reset();
     }
     void insert() {
         if(root.get() == 0) {
             root = make_block<node>(x, x);
         } else {
             root->next = make_block<node>(x, x);
             root->next->prior = root;
             root = root->next;
         }
     }
     ~list()
     {
     }
private:
     block_proxy x;
     block_ptr<node> root;
     };

But I guess I could define a new type like:

struct list {
public:
     [...]
private:
     block_root_ptr<node> root;
     };

Where block_root_ptr could be something like:

template <typename T>
     struct block_root_ptr : private block_proxy, public block_ptr<T>
     {
         block_root_ptr() : block_proxy(), 
block_ptr<T>(static_cast<block_proxy &>(*this)) {}
     };

Subsequent make_*() would follow the respective syntax.  Thanks for your 
input...!

Regards,
-Phil