Add SharedAllocatorList

[jercaianu]

Added the shared version of AllocatorList.
This will be very useful together with SharedAscendingPageAllocator. Instead of mapping a huge chunk of virtual memory when constructing the allocator, we can now use it together with SharedAllocatorList and gradually map smaller chunks of memory on demand.

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[n8sh]

Some things about it seem a bit odd to me, but they're the same as the existing AllocatorList so I'll give this a thumbs up.

[edi33416]

LGTM

[wilzbach]

LGTM too.
I would prefer if we could automatically generate all this locking code with static foreach over the public methods of the base type (D shouldn't be about repeating code).
At the moment we can't generate documentation strings (I think someone was working on a DIP for it, but probably that got stalled).

Also most doc strings miss the Returns/Params ddoc parts.

[wilzbach]

Do we really need this? Can't you use impl.allocators directly?

[wilzbach]

Could be a one-liner:

synchronized(lock) return assumeUnshared(impl).allocate(s);

[wilzbach]

FWIW all the following code could be replaced with a nice static foreach.
Of course the disadvantage is that it won't be shown in the docs, which actually might not be too important.

[wilzbach]

Params need to be documented.

[wilzbach]

Params + Returns

[wilzbach]

Params

[wilzbach]

Params + Returns

[wilzbach]

@jercaianu try sth. like this:

static foreach (T; __traits(allMembers, typeof(impl)))
{
    static if (mixin("isCallable!(impl." ~ T ~ ")") && !T.startsWith("__"))
    static if (mixin("__traits(getProtection, impl." ~ T ~ ") == `public`"))
    {
        mixin(`auto ` ~ T ~ `(Parameters!(impl.`~T~`) params)
        {
            lock.lock();
            scope(exit) lock.unlock();
            return assumeUnshared(impl).`~T~`(params);
        }
        `);
    }
}

[wilzbach]

Oh and if you use synchronized you don't need assumeUnshared because the compiler is then smart enough:

synchronized(mutex) {
  return impl.foo();
}

(though it needs to be a mutex, e.g. new Mutex)

[andralex]

@RazvanN7 can you please look at the compiler bug exposed by the win32 failure?

[andralex]

Please add a comment before this loop explaining what it does. Cool idea @wilzbach !!

[andralex]

Note: this does not work well with rvalues because it copies them once more. Probably not a problem here because all parameters are cheap.

[thewilsonator]

Removing auto merge, this is stalled.

[LightBender]

@thewilsonator this one can be merged with resolutions.