Re: [PATCH V2 1/4] qapi: strList_from_string

[Steven Sistare]

On 2/8/2023 9:17 AM, Alex Bennée wrote:
> Steven Sistare <steven.sistare@oracle.com> writes:
> 
>> On 2/8/2023 1:43 AM, Marc-André Lureau wrote:
>>> Hi
>>>
>>> On Tue, Feb 7, 2023 at 10:50 PM Steve Sistare <steven.sistare@oracle.com> 
>>> wrote:
>>>>
>>>> Generalize hmp_split_at_comma() to take any delimiter character, rename
>>>> as strList_from_string(), and move it to qapi/util.c.
>>>>
>>>> No functional change.
>>>
>>> The g_strsplit() version was a bit simpler, but if you want to
>>> optimize it a bit for 1 char delimiter only, ok.
>>>
>>> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
>>
>> Yes, and it saves a malloc+free for the array.  Small stuff, but I
>> thought it worth a few lines of code.  Thanks for the speedy review!
> 
> But is the HMP path that performance critical? Otherwise I'd favour
> consistent use of the glib APIs because its one less thing to get wrong.

Either implementation is fine with me.  If I use g_strsplit, I will
allow a string delimiter:

strList *strList_from_string(const char *str, const char *delim)
{
    char **split = g_strsplit(str ?: "", delim, -1);
    strList *res = NULL;
    strList **tail = &res;
    int i;

    for (i = 0; split[i]; i++) {
        QAPI_LIST_APPEND(tail, split[i]);
    }

    g_free(split);
    return res;
}

- Steve

>>>> Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
>>>> ---
>>>>  include/monitor/hmp.h  |  1 -
>>>>  include/qapi/util.h    |  9 +++++++++
>>>>  monitor/hmp-cmds.c     | 19 -------------------
>>>>  net/net-hmp-cmds.c     |  2 +-
>>>>  qapi/qapi-util.c       | 23 +++++++++++++++++++++++
>>>>  stats/stats-hmp-cmds.c |  2 +-
>>>>  6 files changed, 34 insertions(+), 22 deletions(-)
>>>>
>>>> diff --git a/include/monitor/hmp.h b/include/monitor/hmp.h
>>>> index 2220f14..e80848f 100644
>>>> --- a/include/monitor/hmp.h
>>>> +++ b/include/monitor/hmp.h
>>>> @@ -19,7 +19,6 @@
>>>>
>>>>  bool hmp_handle_error(Monitor *mon, Error *err);
>>>>  void hmp_help_cmd(Monitor *mon, const char *name);
>>>> -strList *hmp_split_at_comma(const char *str);
>>>>
>>>>  void hmp_info_name(Monitor *mon, const QDict *qdict);
>>>>  void hmp_info_version(Monitor *mon, const QDict *qdict);
>>>> diff --git a/include/qapi/util.h b/include/qapi/util.h
>>>> index 81a2b13..7d88b09 100644
>>>> --- a/include/qapi/util.h
>>>> +++ b/include/qapi/util.h
>>>> @@ -22,6 +22,8 @@ typedef struct QEnumLookup {
>>>>      const int size;
>>>>  } QEnumLookup;
>>>>
>>>> +struct strList;
>>>> +
>>>>  const char *qapi_enum_lookup(const QEnumLookup *lookup, int val);
>>>>  int qapi_enum_parse(const QEnumLookup *lookup, const char *buf,
>>>>                      int def, Error **errp);
>>>> @@ -31,6 +33,13 @@ bool qapi_bool_parse(const char *name, const char 
>>>> *value, bool *obj,
>>>>  int parse_qapi_name(const char *name, bool complete);
>>>>
>>>>  /*
>>>> + * Produce a strList from the character delimited string @in.
>>>> + * All strings are g_strdup'd.
>>>> + * A NULL or empty input string returns NULL.
>>>> + */
>>>> +struct strList *strList_from_string(const char *in, char delim);
>>>> +
>>>> +/*
>>>>   * For any GenericList @list, insert @element at the front.
>>>>   *
>>>>   * Note that this macro evaluates @element exactly once, so it is safe
>>>> diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
>>>> index 34bd8c6..9665e6e 100644
>>>> --- a/monitor/hmp-cmds.c
>>>> +++ b/monitor/hmp-cmds.c
>>>> @@ -39,25 +39,6 @@ bool hmp_handle_error(Monitor *mon, Error *err)
>>>>      return false;
>>>>  }
>>>>
>>>> -/*
>>>> - * Split @str at comma.
>>>> - * A null @str defaults to "".
>>>> - */
>>>> -strList *hmp_split_at_comma(const char *str)
>>>> -{
>>>> -    char **split = g_strsplit(str ?: "", ",", -1);
>>>> -    strList *res = NULL;
>>>> -    strList **tail = &res;
>>>> -    int i;
>>>> -
>>>> -    for (i = 0; split[i]; i++) {
>>>> -        QAPI_LIST_APPEND(tail, split[i]);
>>>> -    }
>>>> -
>>>> -    g_free(split);
>>>> -    return res;
>>>> -}
>>>> -
>>>>  void hmp_info_name(Monitor *mon, const QDict *qdict)
>>>>  {
>>>>      NameInfo *info;
>>>> diff --git a/net/net-hmp-cmds.c b/net/net-hmp-cmds.c
>>>> index 41d326b..30422d9 100644
>>>> --- a/net/net-hmp-cmds.c
>>>> +++ b/net/net-hmp-cmds.c
>>>> @@ -72,7 +72,7 @@ void hmp_announce_self(Monitor *mon, const QDict *qdict)
>>>>                                              migrate_announce_params());
>>>>
>>>>      qapi_free_strList(params->interfaces);
>>>> -    params->interfaces = hmp_split_at_comma(interfaces_str);
>>>> +    params->interfaces = strList_from_string(interfaces_str, ',');
>>>>      params->has_interfaces = params->interfaces != NULL;
>>>>      params->id = g_strdup(id);
>>>>      qmp_announce_self(params, NULL);
>>>> diff --git a/qapi/qapi-util.c b/qapi/qapi-util.c
>>>> index 63596e1..b61c73c 100644
>>>> --- a/qapi/qapi-util.c
>>>> +++ b/qapi/qapi-util.c
>>>> @@ -15,6 +15,7 @@
>>>>  #include "qapi/error.h"
>>>>  #include "qemu/ctype.h"
>>>>  #include "qapi/qmp/qerror.h"
>>>> +#include "qapi/qapi-builtin-types.h"
>>>>
>>>>  CompatPolicy compat_policy;
>>>>
>>>> @@ -152,3 +153,25 @@ int parse_qapi_name(const char *str, bool complete)
>>>>      }
>>>>      return p - str;
>>>>  }
>>>> +
>>>> +strList *strList_from_string(const char *in, char delim)
>>>> +{
>>>> +    strList *res = NULL;
>>>> +    strList **tail = &res;
>>>> +
>>>> +    while (in && in[0]) {
>>>> +        char *next = strchr(in, delim);
>>>> +        char *value;
>>>> +
>>>> +        if (next) {
>>>> +            value = g_strndup(in, next - in);
>>>> +            in = next + 1; /* skip the delim */
>>>> +        } else {
>>>> +            value = g_strdup(in);
>>>> +            in = NULL;
>>>> +        }
>>>> +        QAPI_LIST_APPEND(tail, value);
>>>> +    }
>>>> +
>>>> +    return res;
>>>> +}
>>>> diff --git a/stats/stats-hmp-cmds.c b/stats/stats-hmp-cmds.c
>>>> index 531e35d..4a2adf8 100644
>>>> --- a/stats/stats-hmp-cmds.c
>>>> +++ b/stats/stats-hmp-cmds.c
>>>> @@ -174,7 +174,7 @@ static StatsFilter *stats_filter(StatsTarget target, 
>>>> const char *names,
>>>>              request->provider = provider_idx;
>>>>              if (names && !g_str_equal(names, "*")) {
>>>>                  request->has_names = true;
>>>> -                request->names = hmp_split_at_comma(names);
>>>> +                request->names = strList_from_string(names, ',');
>>>>              }
>>>>              QAPI_LIST_PREPEND(request_list, request);
>>>>          }
>>>> --
>>>> 1.8.3.1
>>>>
>>>>
>>>
>>>
> 
>