Re: Libification project (SoC)

From: Marco Costalba <mcostalba@gmail.com>
Date: Mar 19, 2007, 13:04 UTC
Message-ID: <e5bfff550703190604n6360659cl3880ec5b3a9b5042@mail.gmail.com>
In-Reply-To: <Pine.LNX.4.63.0703191329220.22628@wbgn013.biozentrum.uni-wuerzburg.de>

On 3/19/07, Johannes Schindelin <Johannes.Schindelin@gmx.de> wrote:

Show 20 quoted lines

> Hi,
>
> On Mon, 19 Mar 2007, Marco Costalba wrote:
>
> > On 3/19/07, Johannes Schindelin <Johannes.Schindelin@gmx.de> wrote:
> > >
> > > I don't see _any_ problem in making an API which works with _one_ repo
> > > first. This has several advantages:
> > >
> > > - most users (if any!) will work that way,
> > >
> >
> > Sometime could be useful to write a list of possible users before
> > starting to code.
>
> Fair enough.
>
> I expect the most visible users of libgit to be: the core Git programs!
> Because if we don't eat our own dog food, why should anybody else?
>

But in case you eat your own food, why others should to the same?

> And I am absolutely utterly opposed to make them slower just to support a
> program which wants to cache meta data from multiple repositories.
>

The problem, at least with viewers I know, it's not with multiple repositories but with multiple views of the same repo.

Anyway. Just to give my two cent:

The two possible features we are talking about are:

  - reentrancy (many views open on the same repo)

  - non-blocking behaviour (loading repo in background)

These two features are _very_ different. I agree an async library it's not a small thing, and probably it involves using an external thread library in libgit itself, like pthread, just to not reinventing the (difficult) wheel.

Regarding reentrancy I don't know what is involved in avoiding globals and the like, but I would think it's really an absolute minimum to get people eating your food ;-)

I completely agree that it's impossible to know how a library will be used when you write it, but giving a good look around before to start allows you to get a minimum subset of needed features and if you add a little bit of generalization and you are lucky enough perhaps you will avoid to rewrite the library in the future.

>From the viewers survey and also from the interesting examples of

Steve I would say that do not planning for reentarncy would be a big no-no

  Marco