Re: [Qemu-devel] [PATCH 01/19] Add support for JSON pretty printing

[Luiz Capitulino <lcapitulino@redhat.com>]

On Mon,  7 Jun 2010 15:42:14 +0100
"Daniel P. Berrange" <berrange@redhat.com> wrote:

> The monitor does not pretty-print JSON output, so that everything
> will be on a single line reply. When JSON docs get large this is
> quite unpleasant to read. For the future command line capabilities
> query ability, huge JSON docs will be available. This needs the
> ability to pretty-print.
> 
> This introduces a new API qobject_to_json_pretty() that does
> a minimal indentation of list and dict members. As an example,
> this makes
> 
>   {"QMP": {"version": {"micro": 50, "minor": 12, "package": "", "major": 0}, "capabilities": []}}
> 
> Output as
> 
>   {
>       "QMP": {
>           "version": {
>               "micro": 50,
>               "minor": 12,
>               "package": "",
>               "major": 0
>           },
>           "capabilities": [
>           ]
>       }
>   }
> 
> NB: this is not turned on for the QMP monitor.
> 
> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
> ---
>  qjson.c |   55 +++++++++++++++++++++++++++++++++++++++++++++++--------
>  qjson.h |    1 +
>  2 files changed, 48 insertions(+), 8 deletions(-)
> 
> diff --git a/qjson.c b/qjson.c
> index 483c667..f402103 100644
> --- a/qjson.c
> +++ b/qjson.c
> @@ -72,43 +72,57 @@ QObject *qobject_from_jsonf(const char *string, ...)
>  
>  typedef struct ToJsonIterState
>  {
> +    int indent;
> +    int pretty;
>      int count;
>      QString *str;
>  } ToJsonIterState;
>  
> -static void to_json(const QObject *obj, QString *str);
> +static void to_json(const QObject *obj, QString *str, int pretty, int indent);
>  
>  static void to_json_dict_iter(const char *key, QObject *obj, void *opaque)
>  {
>      ToJsonIterState *s = opaque;
>      QString *qkey;
> +    int j;
>  
> -    if (s->count) {
> +    if (s->count)
>          qstring_append(s->str, ", ");
> +
> +    if (s->pretty) {
> +        qstring_append(s->str, "\n");
> +        for (j = 0 ; j < s->indent ; j++)
> +            qstring_append(s->str, "    ");
>      }
>  
>      qkey = qstring_from_str(key);
> -    to_json(QOBJECT(qkey), s->str);
> +    to_json(QOBJECT(qkey), s->str, s->pretty, s->indent);
>      QDECREF(qkey);
>  
>      qstring_append(s->str, ": ");
> -    to_json(obj, s->str);
> +    to_json(obj, s->str, s->pretty, s->indent);
>      s->count++;
>  }
>  
>  static void to_json_list_iter(QObject *obj, void *opaque)
>  {
>      ToJsonIterState *s = opaque;
> +    int j;
>  
> -    if (s->count) {
> +    if (s->count)
>          qstring_append(s->str, ", ");
> +
> +    if (s->pretty) {
> +        qstring_append(s->str, "\n");

 Nitpick: we also have qstring_append_chr()

> +        for (j = 0 ; j < s->indent ; j++)
> +            qstring_append(s->str, "    ");
>      }
>  
> -    to_json(obj, s->str);
> +    to_json(obj, s->str, s->pretty, s->indent);
>      s->count++;
>  }
>  
> -static void to_json(const QObject *obj, QString *str)
> +static void to_json(const QObject *obj, QString *str, int pretty, int indent)
>  {
>      switch (qobject_type(obj)) {
>      case QTYPE_QINT: {
> @@ -190,8 +204,16 @@ static void to_json(const QObject *obj, QString *str)
>  
>          s.count = 0;
>          s.str = str;
> +        s.indent = indent + 1;
> +        s.pretty = pretty;
>          qstring_append(str, "{");
>          qdict_iter(val, to_json_dict_iter, &s);
> +        if (pretty) {
> +            int j;
> +            qstring_append(str, "\n");
> +            for (j = 0 ; j < indent ; j++)
> +                qstring_append(str, "    ");
> +        }
>          qstring_append(str, "}");
>          break;
>      }
> @@ -201,8 +223,16 @@ static void to_json(const QObject *obj, QString *str)
>  
>          s.count = 0;
>          s.str = str;
> +        s.indent = indent + 1;
> +        s.pretty = pretty;
>          qstring_append(str, "[");
>          qlist_iter(val, (void *)to_json_list_iter, &s);
> +        if (pretty) {
> +            int j;
> +            qstring_append(str, "\n");
> +            for (j = 0 ; j < indent ; j++)
> +                qstring_append(str, "    ");
> +        }
>          qstring_append(str, "]");
>          break;
>      }
> @@ -246,7 +276,16 @@ QString *qobject_to_json(const QObject *obj)
>  {
>      QString *str = qstring_new();
>  
> -    to_json(obj, str);
> +    to_json(obj, str, 0, 0);
> +
> +    return str;
> +}
> +
> +QString *qobject_to_json_pretty(const QObject *obj)
> +{
> +    QString *str = qstring_new();
> +
> +    to_json(obj, str, 1, 0);
>  
>      return str;
>  }
> diff --git a/qjson.h b/qjson.h
> index 7afec2e..cd60e0b 100644
> --- a/qjson.h
> +++ b/qjson.h
> @@ -24,5 +24,6 @@ QObject *qobject_from_jsonf(const char *string, ...)
>  QObject *qobject_from_jsonv(const char *string, va_list *ap);
>  
>  QString *qobject_to_json(const QObject *obj);
> +QString *qobject_to_json_pretty(const QObject *obj);
>  
>  #endif /* QJSON_H */