[Qemu-devel] Re: [PATCH 3/8] Add QBuffer

[Jan Kiszka]

Anthony Liguori wrote:
> On 05/14/2010 08:20 AM, Jan Kiszka wrote:
>> diff --git a/qjson.c b/qjson.c
>> index 483c667..4d1c21a 100644
>> --- a/qjson.c
>> +++ b/qjson.c
>> @@ -19,7 +19,9 @@
>>   #include "qlist.h"
>>   #include "qbool.h"
>>   #include "qfloat.h"
>> +#include "qbuffer.h"
>>   #include "qdict.h"
>> +#include "base64.h"
>>
>>   typedef struct JSONParsingState
>>   {
>> @@ -235,6 +237,20 @@ static void to_json(const QObject *obj, QString
>> *str)
>>           }
>>           break;
>>       }
>> +    case QTYPE_QBUFFER: {
>> +        QBuffer *val = qobject_to_qbuffer(obj);
>> +        size_t data_size = qbuffer_get_size(val);
>> +        size_t str_len = ((data_size + 2) / 3) * 4;
>> +        char *buffer = qemu_malloc(str_len + 3);
>> +
>> +        buffer[0] = '"';
>> +        base64_encode(qbuffer_get_data(val), data_size, buffer + 1);
>> +        buffer[str_len + 1] = '"';
>> +        buffer[str_len + 2] = 0;
>> +        qstring_append(str, buffer);
>> +        qemu_free(buffer);
>> +        break;
>> +    }
>>    
> 
> Instead of encoding just as a string, it would be a good idea to encode
> it as something like:
> 
> {'__class__': 'base64', 'data': ...}
> 
> We've discussed using hidden properties to describe special things like
> abstract classes and since we already have this namespace reserved, I
> think it's a good time to use it.
> 
> The advantage is that in a dynamic language like Python, the parser can
> convert base64 to binary strings automatically without having to
> understand the QMP protocol.

Indeed, was amazingly simple to add and works nicely with qmp-shell as
demonstrator. Will repost, also to fix a few remaining glitches I came
across in the meantime.

Jan

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