[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH v3] qemu-img: correct size parsers and help mess
From: |
Eric Blake |
Subject: |
Re: [Qemu-devel] [PATCH v3] qemu-img: correct size parsers and help message |
Date: |
Wed, 18 Jul 2012 07:34:37 -0600 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:13.0) Gecko/20120615 Thunderbird/13.0.1 |
On 07/18/2012 07:23 AM, Dong Xu Wang wrote:
> qemu-img not only suports k/K/M/G/T/b, but also supports m/g/t/B. So correct
> it in help message.
>
> +++ b/qemu-img.c
> @@ -69,8 +69,9 @@ static void help(void)
> " options are: 'none', 'writeback' (default, except for
> convert), 'writethrough',\n"
> " 'directsync' and 'unsafe' (default for convert)\n"
> " 'size' is the disk image size in bytes. Optional suffixes\n"
> - " 'k' or 'K' (kilobyte, 1024), 'M' (megabyte, 1024k), 'G'
> (gigabyte, 1024M)\n"
> - " and T (terabyte, 1024G) are supported. 'b' is ignored.\n"
> + " 'k' or 'K' (kilobyte, 1024), 'm' or 'M' (megabyte, 1024k),\n"
> + " 'g' or 'G' (gigabyte, 1024M) and 't' or 'T' (terabyte,
> 1024G) are supported.\n"
> + " 'b' or 'B' is ignored.\n"
Technically, 'kilobyte' is only 1000 bytes; the correct term for 1024
bytes is 'kibibyte'. Likewise for 'megabyte' (1000000) vs. 'mebibyte'
(1024k, or 1,048,576 bytes); and so on for gibibytes and tebibytes.
Since disk manufacturers have already forced the rest of the world to
ask whether the number of bytes they are looking at is a power of 10 or
a power of 2 suffix, we might as well be precise in our naming to
document that we really are using powers of 2.
Furthermore, I think you can compress this by mentioning that the parse
is case-insensitive, instead of spelling out all the options:
'size' is the disk image size in bytes, scaled by an optional
case-insensitive suffix: 'k' (kibibyte, 1024), 'M' (mebibyte, 1024k),
'G' (gibibyte, 1024M), 'T' (tebibyte, 1024G), or 'b' (no scaling).
> @@ -341,8 +342,8 @@ static int img_create(int argc, char **argv)
> char *end;
> sval = strtosz_suffix(argv[optind++], &end, STRTOSZ_DEFSUFFIX_B);
> if (sval < 0 || *end) {
> - error_report("Invalid image size specified! You may use k, M, G
> or "
> - "T suffixes for ");
> + error_report("Invalid image size specified! You may use k/K,
> m/M, "
> + "g/G or t/T suffixes for ");
I personally dislike this change. Just because we're lenient in what we
accept does not mean we have to document all of the possibilities that
we parse when correcting a user error; rather, we need only document the
preferred possibilities.
> default:
> error_set(errp, QERR_INVALID_PARAMETER_VALUE, name, "a size");
> - error_printf_unless_qmp("You may use k, M, G or T suffixes for "
> + error_printf_unless_qmp("You may use K/k, M/m, G/g or T/t
> suffixes for "
Again, in an error message, I'd only document the preferred capitalization.
--
Eric Blake address@hidden +1-919-301-3266
Libvirt virtualization library http://libvirt.org
signature.asc
Description: OpenPGP digital signature