Re: Destructors and Deterministic Memory Management

[Sean Kelly]

dsimcha wrote:
Two closely related topics here:
1.  It is often nice to be able to create a single object that works with both
GC and deterministic memory management.  The idea is that, if delete is called
manually, all sub-objects would be freed deterministically, but the object
could still safely be GC'd.  Since the destructor called by the GC can't
reference sub-objects, would it be feasible to have two destructors for each
class, one that is called when delete is invoked manually and another that is
called by the GC?

You can do this today with both Druntime on D 2.0 and Tango on D 1.0, 
though it isn't the most performant approach.  The code would look 
something like this:

import core.runtime;

interface Disposable
{
    void dispose();
}

bool handler( Object o )
{
    auto d = cast(Disposable) o;

    if( d !is null )
    {
        d.dispose();
        return false;
    }
    return true;
}

static this()
{
    Runtime.collectHandler = &handler;
}

If you return false from your collectHandler then the runtime won't call 
the object's dtor.