[libvirt] [PATCH 02/13] improve the iteration of VSH_OT_ARGV options

[Daniel P. Berrange]

On Wed, May 25, 2011 at 05:37:44PM +0800, Lai Jiangshan wrote:
> Signed-off-by: Lai Jiangshan <laijs at fujitsu.com>
> ---
>  tools/virsh.c |   47 ++++++++++++++++++++++++-----------------------
>  1 files changed, 24 insertions(+), 23 deletions(-)
> 
> diff --git a/tools/virsh.c b/tools/virsh.c
> index c358580..2e27535 100644
> --- a/tools/virsh.c
> +++ b/tools/virsh.c
> @@ -277,7 +277,27 @@ static int vshCommandOptULongLong(const vshCmd *cmd, const char *name,
>                                    unsigned long long *value)
>      ATTRIBUTE_NONNULL(3) ATTRIBUTE_RETURN_CHECK;
>  static bool vshCommandOptBool(const vshCmd *cmd, const char *name);
> -static char *vshCommandOptArgv(const vshCmd *cmd, int count);
> +
> +/*
> + * Iterate all the argv arguments.
> + *
> + * Requires that a VSH_OT_ARGV option  be last in the
> + * list of supported options in CMD->def->opts.
> + */
> +static inline const vshCmdOpt *__variable_arg(const vshCmdOpt *opt)
> +{
> +    while (opt) {
> +         if (opt->def && opt->def->type == VSH_OT_ARGV)
> +             break;
> +         opt = opt->next;
> +    }
> +
> +    return opt;
> +}
> +
> +#define for_each_variable_arg(cmd, opt)                                       \
> +    for (opt = __variable_arg(cmd->opts); opt; opt = __variable_arg(opt->next))
> +
>  
>  #define VSH_BYID     (1 << 1)
>  #define VSH_BYUUID   (1 << 2)
> @@ -10059,6 +10079,7 @@ cmdEcho (vshControl *ctl ATTRIBUTE_UNUSED, const vshCmd *cmd)
>      bool shell = false;
>      bool xml = false;
>      int count = 0;
> +    const vshCmdOpt *opt;
>      char *arg;
>      virBuffer buf = VIR_BUFFER_INITIALIZER;
>  
> @@ -10067,10 +10088,11 @@ cmdEcho (vshControl *ctl ATTRIBUTE_UNUSED, const vshCmd *cmd)
>      if (vshCommandOptBool(cmd, "xml"))
>          xml = true;
>  
> -    while ((arg = vshCommandOptArgv(cmd, count)) != NULL) {
> +    for_each_variable_arg(cmd, opt) {
>          bool close_quote = false;
>          char *q;
>  
> +        arg = opt->data;
>          if (count)
>              virBufferAddChar(&buf, ' ');
>          /* Add outer '' only if arg included shell metacharacters.  */
> @@ -11484,27 +11506,6 @@ vshCommandOptBool(const vshCmd *cmd, const char *name)
>      return vshCommandOpt(cmd, name) != NULL;
>  }
>  
> -/*
> - * Returns the COUNT argv argument, or NULL after last argument.
> - *
> - * Requires that a VSH_OT_ARGV option with the name "" be last in the
> - * list of supported options in CMD->def->opts.
> - */
> -static char *
> -vshCommandOptArgv(const vshCmd *cmd, int count)
> -{
> -    vshCmdOpt *opt = cmd->opts;
> -
> -    while (opt) {
> -        if (opt->def && opt->def->type == VSH_OT_ARGV) {
> -            if (count-- == 0)
> -                return opt->data;
> -        }
> -        opt = opt->next;
> -    }
> -    return NULL;
> -}
> -
>  /* Determine whether CMD->opts includes an option with name OPTNAME.
>     If not, give a diagnostic and return false.
>     If so, return true.  */

I'm not entirely sure I understand what the effect of this patch
is. Can you explain what the change in semantics for the parser
is with this patch applied

Regards,
Daniel
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