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From: Eric Sunshine <sunshine@sunshineco.com>
To: randall.s.becker@rogers.com
Cc: Git List <git@vger.kernel.org>,
	"Randall S. Becker" <rsbecker@nexbridge.com>
Subject: Re: [Patch v1 1/3] test-lib-functions.sh: add generate_zero_bytes function
Date: Sat, 9 Feb 2019 21:05:04 -0500	[thread overview]
Message-ID: <CAPig+cRARdkKN-wR4EzVSzxuK51VOPf-kFFG57kkEsnFBfe4TA@mail.gmail.com> (raw)
In-Reply-To: <20190209185930.5256-2-randall.s.becker@rogers.com>

On Sat, Feb 9, 2019 at 1:59 PM <randall.s.becker@rogers.com> wrote:
> t5318 and t5562 used /dev/zero, which is not portable. This function
> provides both a fixed block of NUL bytes and an infinite stream of NULs.
>
> Signed-off-by: Randall S. Becker <rsbecker@nexbridge.com>
> ---
> diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
> @@ -116,6 +116,19 @@ remove_cr () {
> +# Generate an output of $1 bytes of all zeroes (NULs, not ASCII zeroes).
> +# If $1 is 'infinity', output forever or until the receiving pipe stops reading,
> +# whichever comes first.

This is a somewhat unusual API. A (perhaps) more intuitive behavior
would be for it to emit an infinite stream of NULs when given no
argument, and a limited number of NULs when given an argument.
Redefining the behavior like that also fixes the "problem" with the
current implementation erroring-out if no argument is provided.

> +generate_zero_bytes () {
> +       perl -e 'if ($ARGV[0] == "infinity") {

s/perl/"$PERL_PATH"/

> +               while (-1) {
> +                       print "\0"
> +               }

Or, more compactly:

    print "\0" while 1;

> +       } else {
> +               print "\0" x $ARGV[0]
> +       }' "$@"
> +}

  reply	other threads:[~2019-02-10  2:06 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-09 18:59 [Patch v1 0/3] 2.21.0-rc0 test fixes resulting from use of /dev/zero randall.s.becker
2019-02-09 18:59 ` [Patch v1 1/3] test-lib-functions.sh: add generate_zero_bytes function randall.s.becker
2019-02-10  2:05   ` Eric Sunshine [this message]
2019-02-10 19:19     ` Randall S. Becker
2019-02-12  0:37     ` Jeff King
2019-02-12  1:17       ` Eric Sunshine
2019-02-12  2:47         ` randall.s.becker
2019-02-09 18:59 ` [Patch v1 2/3] t5318: replace use of /dev/zero with generate_zero_bytes randall.s.becker
2019-02-10  2:07   ` Eric Sunshine
2019-02-12 17:18     ` Junio C Hamano
2019-02-13 17:25       ` Junio C Hamano
2019-02-13 18:18         ` Randall S. Becker
2019-02-13 21:00           ` Junio C Hamano
2019-02-13 21:03             ` Randall S. Becker
2019-02-09 18:59 ` [Patch v1 3/3] t5562: replace /dev/zero with a pipe from generate_zero_bytes randall.s.becker
2019-02-10  2:12   ` Eric Sunshine
2019-02-12 17:24     ` Junio C Hamano
2019-02-12 20:50       ` Johannes Sixt
2019-02-13 17:26         ` Junio C Hamano
2019-02-15 16:42   ` [PATCH] t5562: do not depend on /dev/zero Max Kirillov
2019-02-15 17:13     ` Randall S. Becker
2019-02-15 18:00       ` Junio C Hamano
2019-02-15 18:10         ` Randall S. Becker
2019-02-15 18:45           ` Junio C Hamano

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