[vlmc-devel] [PATCH 1/4] Settings: Use Base64 to save QByteArray

[yikei lu]

Yes, you are right. QJsonValue doesn't support loading QByteArray. You
can confirm it with the documentation. :)

2016-05-02 20:11 GMT+09:00 Hugo Beauzée-Luyssen <hugo at beauzee.fr>:
> On 05/01/2016 05:56 AM, yikei lu wrote:
>>
>> FYI, saveGeometry() will create a byte array like
>>
>> "\001ÙÐË\000\002\000\000ÿÿþu\000\000\000L\000\000\003R\000\000\002¾ÿÿþv\000\000\000f\000\000\003Q\000\000\002½\000\000\000\000\000\000\000\000\007\200"
>>
>> saveState():
>>
>> "\000\000\000ÿ\000\000\000\000ý\000\000\000\001\000\000\000\002\000\000\004Ü\000\000\001\004ü\001\000\000\000\005û\000\000\000\030\000M\000e\000d\000i\000a\000L\000i\000b\000r\000a\000r\000y\001\000\000\000\000\000\000\001\030\000\000\001\030\000ÿÿÿû\000\000\000\030\000E\000f\000f\000e\000c\000t\000s\000
>> \000L"... (327)
>>
>> A LOT OF \0 !!!
>>
>> 2016-05-01 12:48 GMT+09:00 yikei lu <luyikei.qmltu at gmail.com>:
>>>
>>> "QByteArray QMainWindow::saveState(int version = 0) const" is. It will
>>> always start with \0 in my case, which makes QJsonValue mistakenly
>>> recognizes it as null.
>>> Also, saveGeometry() doesn't work since there must be \0 anywhere in
>>> the QByteArray.
>>> So you can see that unless the patch be applied, you can't save and
>>> restore the mainwindow's state/geometry.
>>>
>>> You can confirm this with vlmc.conf
>>>
>>> 2016-05-01 2:03 GMT+09:00 Hugo Beauzée-Luyssen <hugo at beauzee.fr>:
>>>>
>>>> On 04/29/2016 10:05 AM, Yikai Lu wrote:
>>>>>
>>>>> "Note: A QByteArray can store any byte values including '\0's, but most
>>>>> functions that take char * arguments assume that the data ends at the first
>>>>> '\0' they encounter."
>>>>>
>>>>> Because of the above, we can't save QByteArray directly.
>>>>> ---
>>>>>   src/Settings/Settings.cpp | 13 +++++++++++--
>>>>>   1 file changed, 11 insertions(+), 2 deletions(-)
>>>>>
>>>>> diff --git a/src/Settings/Settings.cpp b/src/Settings/Settings.cpp
>>>>> index b8cef75..2092d59 100644
>>>>> --- a/src/Settings/Settings.cpp
>>>>> +++ b/src/Settings/Settings.cpp
>>>>> @@ -159,8 +159,14 @@ Settings::loadJsonFrom( const QJsonObject &object
>>>>> )
>>>>>           if ( isChildSettings == true )
>>>>>               continue;
>>>>>
>>>>> -        if ( setValue( it.key(), (*it).toVariant() ) == false )
>>>>> +        SettingValue* val = value( it.key() );
>>>>> +        if ( val == nullptr )
>>>>>               vlmcWarning() << "Loaded invalid project setting:" <<
>>>>> it.key();
>>>>> +
>>>>> +        if ( val->type() == SettingValue::ByteArray )
>>>>> +            val->set( QByteArray::fromBase64(
>>>>> (*it).toVariant().toByteArray() ) );
>>>>> +        else
>>>>> +            val->set( (*it).toVariant() );
>>>>>       }
>>>>>       emit postLoad();
>>>>>   }
>>>>> @@ -173,7 +179,10 @@ Settings::saveJsonTo( QJsonObject &object )
>>>>>       {
>>>>>           if ( ( val->flags() & SettingValue::Runtime ) != 0 )
>>>>>               continue ;
>>>>> -        object.insert( val->key(), QJsonValue::fromVariant( val->get()
>>>>> ) );
>>>>> +        if ( val->type() == SettingValue::ByteArray )
>>>>> +            object.insert( val->key(), QJsonValue( QString(
>>>>> val->get().toByteArray().toBase64() ) ) );
>>>>> +        else
>>>>> +            object.insert( val->key(), QJsonValue::fromVariant(
>>>>> val->get() ) );
>>>>>       }
>>>>>   }
>>>>>
>>>>>
>>>> Is there a specific case where this would be an issue?
>>>>
>>>> --
>>>> Hugo Beauzée-Luyssen
>>>> www.beauzee.fr
>>>> _______________________________________________
>>>> Vlmc-devel mailing list
>>>> Vlmc-devel at videolan.org
>>>> https://mailman.videolan.org/listinfo/vlmc-devel
>>
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>>
>
> Oh ok I got it now, though the way I understand it, the problem isn't linked
> with conversions to char* per-se, but rather that QJsonValue doesn't know
> QByteArray, so it will use the QString conversion, which indeed fails.
> This seems like a lack of feature in Qt, but your patch seems to be a proper
> workaround, thanks!
>
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