[Xapian-tickets] [Xapian] #554: Complement clone() method with destroy()

[Xapian]

#554: Complement clone() method with destroy()
-------------------------+--------------------------------------------------
 Reporter:  olly         |       Owner:  olly 
     Type:  enhancement  |      Status:  new  
 Priority:  normal       |   Milestone:  1.3.0
Component:  Library API  |     Version:       
 Severity:  normal       |    Keywords:       
Blockedby:               |    Platform:  All  
 Blocking:               |  
-------------------------+--------------------------------------------------

Comment(by olly):

 Oh, actually the user can implement {{{operator new}}} and {{{operator
 delete}}} in their subclass, and that approach doesn't require an extra
 virtual method, or the (admittedly small) overhead of calling it for each
 object destroyed.

 This code demonstrates that this works for the situation we'd have:

 {{{
 #!cpp
 #include <iostream>

 using namespace std;

 class Base {
     int x;
   public:
     Base(int x_) : x(x_) { }
     virtual ~Base() { }
 };

 class Derived : public Base {
   public:
     Derived(int x_) : Base(x_) { }

     static void* operator new(size_t size) {
         cout << "Derived::new(" << size << ")" << endl;
         return ::operator new(size);
     }

     static void operator delete(void * p, size_t size) {
         cout << "Derived::delete(" << size << ")" << endl;
         ::operator delete(p);
     }
 };

 int main() {
     Base * o = new Derived(42);
     delete o;
 }
 }}}

 This trick probably also opens the way to wrapping {{{Xapian::Weight}}}
 (#401).

-- 
Ticket URL: <http://trac.xapian.org/ticket/554#comment:1>
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