On 01/13/2012 11:17 AM, Peter Krempa wrote:
> This patch adds an optional attribute note="" to the <description>
> element in the domain XML. This attribute can hold a short note defined
> by the user to ease the identification of domains. The note is limited
> to 40 characters.
I'd go one step further, and reject newlines.
>
> *docs/formatdomain.html.in
> *docs/schemas/domaincommon.rng
> - add schema grammar for the new element and documentation
>
> *src/conf/domain_conf.c
> *src/conf/domain_conf.h
> - add field to hold the new attribute
> - add code to parse and create XML with the new attribute
> ---
> docs/formatdomain.html.in | 7 +++++--
> docs/schemas/domaincommon.rng | 14 +++++++++++++-
> src/conf/domain_conf.c | 27 +++++++++++++++++++++++++--
> src/conf/domain_conf.h | 1 +
> 4 files changed, 44 insertions(+), 5 deletions(-)
>
> @@ -58,7 +59,9 @@
> <dd>The content of the <code>description</code> element provides a
> human readable description of the virtual machine. This data is not
> used by libvirt in any way, it can contain any information the user
> - wants. <span class="since">Since 0.7.2</span></dd>
> + wants. <span class="since">Since 0.7.2</span> The optional attribute
> + <code>note</code> provides space for a shorter description.
> + <span class="since">Since 0.9.10</span></dd>
The end result has confusing punctuation. I'd suggest:
+ wants, <span class="since">since 0.7.2</span>. The optional attribute
+ <code>note</code> provides space for a shorter description,
+ capped at 40 bytes and with no newline,
+ <span class="since">since 0.9.10</span>.</dd>
> +++ b/docs/schemas/domaincommon.rng
> @@ -10,7 +10,19 @@
> -->
> <define name="description">
> <element name="description">
> - <text/>
> + <optional>
> + <attribute name="note">
> + <data type="string"/>
We can make this enforce length restrictions:
<data type="string">
<param name='pattern'>[^\n]{0,40}</param>
</data>
> + </attribute>
> + </optional>
> + <choice>
> + <group>
> + <text/>
> + </group>
> + <group>
> + <empty/>
> + </group>
> + </choice>
No need for a <group> around a single element. This whole layout may
change if we go with an optional <title> instead of <description
note='...'>, but I'd almost rather see:
<element name='description'>
<choice>
<group>
<attribute name='note'>...</attribute>
<choice>
<text/>
<empty/>
</choice>
</group>
<text/>
</choice>
</element>
that is, you must have the attribute, or text, or both, but not
<description/> with neither.
> + /* Extract short description of domain (note) */
> + def->note = virXPathString("string(./description[1]/@note)", ctxt);
> + if (def->note) {
> + if (strchr(def->note, '\n')) {
> + virDomainReportError(VIR_ERR_XML_ERROR,
> + "%s", _("Note attribute can't contain newlines"));
> + goto error;
> + }
> +
> + if (strlen(def->note) > 40) {
This checks for bytes, not characters (some 40-character UTF-8 strings
can occupy well more than 100 bytes). I'm probably okay with a byte
limit, but hope we don't get complaints about someone unable to write a
single word of 12 characters in their favorite locale.
--
Eric Blake eblake@xxxxxxxxxx +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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