Re: [Qemu-devel] [PATCH] RFC: options parse in vl.c should be moduled

[Anthony Liguori <aliguori@us.ibm.com>]

On 03/30/2012 11:09 AM, Anthony Liguori wrote:
> On 03/30/2012 10:59 AM, Lluís Vilanova wrote:
>> Wanpeng Li writes:
>>
>>> Consider of the options parse process in main function of vl.c is too
>>> long.It should be module into single function to clear ideas, strengthen
>>> the source code management, and increase code readability.So I module the
>>> process of options parse as function options_parse, and expose some variables
>>> in order to not influence command-line invocations.
>>
>> Another approach would be to use something similar to QOM type registration.
>>
>> In order to keep code to a minimum, you can define an array of pointers to
>> QParameter structures, instead of an array of function pointers (what
>> __attribute__((constructors)) does).
>>
>> So, for example:
>>
>> static void opt_icount_handler(const char *args)
>> {
>> if (kvm_enabled() || xen_enabled()) {
>> fprintf(stderr, "-icount is not allowed with kvm or xen\n");
>> exit(1);
>> }
>> /* ... contents of configure_icount ... */
>> }
>>
>> static QEMUOption opt_icount = {
>> .name = "icount",
>> .signature = "[N|auto]",
>> .help = "enable virtual instruction counter with 2^N clock ticks per
>> instruction",
>> .mode = QEMU_MODE_SYSTEM,
>> .priority = QEMU_OPT_PRIO_BEFORE_DEVICES,
>> .section = QEMU_OPT_SECTION_DEBUG,
>> .handler = opt_icount_handler
>> };
>>
>> param_register(opt_icount);
>>
>>
>> Here, param_register would define an array of pointers to QEMUOption structures,
>> although I'm not sure how this can be handled on formats other than ELF.
>
> My plan is to have a -query-capabilities so we can change the help text, then
> use GOptionContext.
>
> It would take a small function that goes through and promotes any option in the
> format '-foo' to '--foo'. But that's not too hard.
>
> Then we can completely rip out the option parsing, qemu-options.hx, and all of
> that other junk.

glib's option parsing support has some really nice features like translation 
support, grouping, and inline help for option definition.

The grouping is a really nice touch.  It will let us have a target specific 
group, device groups, etc.

Regards,

Anthony Liguori

>
> Regards,
>
> Anthony Liguori
>