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From Greg Stein <gst...@lyra.org>
Subject Re: Filtered I/O ... again. :-)
Date Sat, 03 Jun 2000 10:51:19 GMT
On Sat, 3 Jun 2000, Life is hard, and then you die wrote:
> On Wed, May 31, 2000 at 02:50:10PM -0700, Greg Stein wrote:
>...
> > Oh. That is better than my first pass on this. In my proposal, I said a
> > zero-length buffer. But I can easily see a mistake where zero-length is
> > passed (ap_rwrite(buf, len, r) without testing "len"), thus making things
> > believe they just hit EOF. Better is a NULL pointer for the buffer. Even
> > if somebody passes len==0, I find it quite "impossible" for them to
> > arrange a NULL buffer pointer. If they do... TFB for them. That is like
> > expecting ap_rwrite(NULL, 0, r) to "work". Negative!
> 
> Overloading ap_rwrite() will work, but I feel adding ap_rclose() would be
> cleaner/more natural.

Nobody would be calling ap_rwrite(NULL, ...) or ap_rclose().

In ap_finalize_request_protocol(), Apache will tell the filters to flush
their state. It does this by passing a NULL buffer.

The conversation with myself (above) was whether a NULL buffer could be
confused with "normal operation", or whether it was a good signal to
flush. My answer is that nobody is going to be able to pass a NULL buffer,
so it is fine.

Technically, we could have filters implement a close/flush function, but
we've been attempting to minimize the number of entry points for them (for
simplicity).

Cheers,
-g

-- 
Greg Stein, http://www.lyra.org/


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