On 05/26/2011 12:38 AM, Daniel P. Berrange wrote:
> On Wed, May 25, 2011 at 05:37:44PM +0800, Lai Jiangshan wrote:
>> Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxx>
>> ---
>> 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
>
"for_each_XXXX" macro is more friendly/directly, it very common in linux kernel.
"while ((arg = vshCommandOptArgv(cmd, count)) != NULL)" is O(N*N) time.
"while ((arg = vshCommandOptArgv(cmd, count)) != NULL)" requires a "count" to control the iteration.
Thanks,
Lai
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