subversion-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Ivan Zhakov <i...@visualsvn.com>
Subject Re: svn commit: r1701633 - /subversion/trunk/subversion/libsvn_subr/stream.c
Date Tue, 08 Sep 2015 09:21:19 GMT
On 7 September 2015 at 18:06,  <kotkov@apache.org> wrote:
> Author: kotkov
> Date: Mon Sep  7 15:06:57 2015
> New Revision: 1701633
>
> URL: http://svn.apache.org/r1701633
> Log:
> Fix svn_stream_for_stdin() and related functions for STDOUT and STDERR
> that were returning streams with mark() and seek() capabilities.
>
> STDIN, STDOUT and STDERR don't provide general support for positioning
> requests.  This behavior is implementation-specific and depends on what's
> passed as the corresponding handle.  For example, on Linux, apr_file_seek()
> that calls lseek() internally fails with ESPIPE [1] when the descriptor is
> associated with a terminal device.  As we cannot safely advertise mark()
> and seek() support for these streams, don't do that.
>
> [1] http://pubs.opengroup.org/onlinepubs/9699919799/functions/lseek.html
>
> * subversion/libsvn_subr/stream.c
>   (svn_stream_for_stdin, svn_stream_for_stdout, svn_stream_for_stderr):
>    Don't install mark and seek handlers.
>
It may be worth to introduce local helper like
'make_stream_from_apr_file(svn_boolean_t supports_seek)' and use it in
svn_stream_from_apr_file2() and svn_stream_for_stdin() instead of
clearing mark/seek handlers after calling svn_stream_from_apr_file2().

Another problem that currently svn_stream_t for stdin/stderr/stdout
pretends to support native svn_stream_skip(), while I'm not sure that
all platforms support seek for stdin.

-- 
Ivan Zhakov

Mime
View raw message