[webkit-dev] Simplifying "hub" classes (was Cleaning up directories in WebCore)

[Hajime Morrita]

One traditional pattern is to split a big class into  a set small
classes plus a "hub" class
like how Adam has done for original Frame.
In that pattern, small classes has a reference to the hub class and
know its API.
I hope these small classes know just a small part of its hub class via
interface (abstract class.)
In that way, such classes can be unit-tested independently without
instantiating the hub class,
whose instantiation is typically a difficult job.

Personally, I feel that we don't need category-like mixin mechanism
for existing hub classes.
Since we have just a few or dozen of instances of these classes and
the size overhead from extra pointers
is negligible. It isn't case for the node family though.

--
morrita

On Sun, Nov 20, 2011 at 2:23 AM, Adam Roben <aroben at apple.com> wrote:
> On Nov 18, 2011, at 5:55 PM, Adam Barth wrote:
>
>> Really, SQL_DATABASE just wants to store some state per
>> ScriptExecutionContext.  It seems like there should be a way to do
>> that without making a mess of ScriptExecutionContext.
>>
>> IMHO, we want something like the C++ equivalent of Objective-C
>> categories.  I'm not sure how best to achieve that.
>
> Note that ObjC categories don't allow you to add extra state (i.e., ivars) to classes. They only allow you to add extra methods.
>
> -Adam
>
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-- 
morrita