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Date: Mon, 15 Mar 2010 18:37:19 -0500
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] [PATCH 1/7] Add support for generic notifier lists
References: <1268239869-16058-1-git-send-email-aliguori@us.ibm.com>	<201003111257.59828.paul@codesourcery.com>	<4B98F99F.1000506@codemonkey.ws>	<201003111419.53494.paul@codesourcery.com>
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To: Anthony Liguori <aliguori@linux.vnet.ibm.com>
Cc: qemu-devel@nongnu.org, Gerd Hoffman <kraxel@redhat.com>, Paul Brook <paul@codesourcery.com>, Luiz Capitulino <lcapitulino@redhat.com>

On 03/15/2010 03:31 PM, Anthony Liguori wrote:
> On 03/11/2010 08:19 AM, Paul Brook wrote:
>>> On 03/11/2010 06:57 AM, Paul Brook wrote:
>>>>> +struct QEMUNotifier
>>>>> +{
>>>>> +    void (*notify)(QEMUNotifier *notifier);
>>>>> +};
>>>> I suggest combining this with QEMUBH.
>>> I take it your not opposed to converting QEMUBH to be a QEMUNotifier?
>>> If so, I'm happy to do it.
>> It's unclear to me why you've invented a new thing in the first place.
>
> It's a better approximation of the command pattern because the command 
> is a single object as opposed to a tuple.  Because the command is an 
> object, you can also do things like binding.  For instance:

typedef struct IONotifier
{
    Notifier parent;
    void (*notify)(IONotifier *notifier, int fd);
    int fd;
} IONotifier;

It's been a long day...

> Which now gives you a notifier that has an fd bound to it's second 
> argument (which is pretty useful for IO dispatch).
>
> You can do this with a tuple representation, but it gets awkward.  One 
> could argue for formalizing the tuple as a struct but extending by 
> nesting becomes more complicated.  Also, for the most part, you 
> already have a state for the command and embedding the object means 
> less dynamic memory allocation and less code to handle that.
>
> Regards,
>
> Anthony Liguori
>

Regards,

Anthony Liguori