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Subject: File buckets v. core_output_filter
From: Bojan Smojver <bojan@rexursive.com>
To: Apache Dev List <dev@httpd.apache.org>
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Organization: Rexursive
Message-Id: <1060256982.1293.28.camel@beast.rexursive.com>
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Date: Thu, 07 Aug 2003 21:49:42 +1000
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Greetings everyone, it has been a while since I posted my ramblings
about mod_logio... Anyway, it's that time of the year again :-)

I'm working on a new module and I have hit a strange problem in relation
to core_output_filter, which is as far as I can see affecting my output.

Let's say I have a file that contains 300 bytes of something I'm
interested in, then 10 bytes of rubbish, then 300 bytes of good stuff
again and so on. The reason I'm picking 300 bytes here is because this
number is greater than AP_MIN_SENDFILE_BYTES, which is 256.

So, I build up a brigade that looks like this:

FILE - POOL - FILE - POOL - FILE - EOS

The POOL buckets contains something useful instead of 10 bytes of
rubbish that I would normally find in the file. The file buckets are
chunks of the same file that I'm interested in.

When I pass this to output filters in my handler with
ap_pass_brigade(r->output_filters,bb), I'm getting completely random
output from. In other words, offsets of FILE buckets are completely
screwed or buckets down show up at all.

If I, however, build a brigade like this:

FILE - FLUSH - POOL - FILE - FLUSH - POOL - FILE - FLUSH - EOS

then it all works fine. Also, if the good parts of my file are below 256
bytes (or if I increase AP_MIN_SENDFILE_BYTES above the threshold),
there are no problems at all.

I was testing this all this on 2.0.46, Red Hat Linux 9. Has anyone else
observed anything like that? Has anything like that been fixed lately?

Or am I simply doing something really stupid...

-- 
Bojan