Re: [Lxde-list] [razor-qt] About dconf - proof of concept

[Kuzma S. <lea...@gm...>]

1. actually it's not a problem of this library, though using default values
- is a big advantage.
BTW even fixing a "plain text" ini files can be troublesome. Try to fix
something like: State="@ByteArray(\0\0\0\xff\0\0\0\x2\xfd ... 4 more lines
... \xfc\0\0\0\0)" ;-) (it's from QtCreator.ini)

2. I'll see what I can do to expose this functionality in API.

3. well, I looked close at dconf-qt and I'm sure we want to use our own
solution.
I think we'll create a similar (but not an exact copy) API to QSettings to
some extent - as was mentioned before dconf-based settings have some
additional features like descriptions and default values, but do not have
scopes, fallbacks and formats as QSettings class does.
And if one day Qt supports dconf natively - we'll see, maybe there will be
no advantage to migrate.

4. Actually, I was going to preserve types as much as possible, but just as
a concept your class is great!

Cheers,
Kuzma


On 7 August 2013 18:10, Jerome Leclanche <ad...@gm...> wrote:

>
> On Wed, Aug 7, 2013 at 7:00 AM, PCMan <pcm...@gm...> wrote:
>
>> On Wed, Aug 7, 2013 at 1:29 PM, Kuzma Shapran <lea...@gm...>
>> wrote:
>> > @PCMan: I looked at lxqt-settings - it's good start. I'm currently
>> improving
>> > it in my fork (https://github.com/kuzmas/lxqt-settings) - some style
>> > formatting, C++ vs. C ways of doing things, and the main: hiding
>> > implementation into a private class to have more or less stable ABI.
>> >
>> > @Christian: Also I looked at dconf docs - there is a way to monitor
>> > modifications, so adding signals for this is in my todo list as well.
>> >
>> > Cheers,
>> > Kuzma
>>
>> Thank you for taking this over.
>> I'm sure you'll make it better.
>> While doing dconf thing, I encountered some problems, though.
>>
>> 1. The config is stored using a binary format. What will happen if
>> it's corrupted? There is no easy way to fix a broken configuration
>> without using either a GUI editor "dconf-editor" or a command-line
>> tool. Fixing a wrong plain text config file with an editor is much
>> easier. When something goes wrong and you cannot login your desktop
>> session, it's hard to fix the config with command line tools. If we
>> can have a set of "default values" and can let the user restore the
>> default easily, this solves the problem partially.
>>
>> 2. While the glib implementation GSettings supports schemes, default
>> values, and type checking, my implementation just does raw read and
>> write for the values. No type checking or default values are handled.
>> It might be better to use glib GSettings? Otherwise, default values
>> need to be hard-coded in applications themselves.
>>
>
> This was, once again, brought up at the desktop summit (to much heat). Qt
> would never itself have a gsettings backend (not in its current state) as
> it doesn't want the dependency on GIO. I don't think we want that either.
> Ryan Lortie brought up that gsettings could possibly become more
> independent, which would be interesting, however I haven't followed up on
> that.
>
>
>>
>> 3. Should we use dconf-qt, which is done by Canonical instead, or
>> using our own simple class mimicking QSettings? Personally I prefer
>> our own solution and this can be included in liblxqt.
>>
>
> Seeing as dconf support will ultimately end up in Qt (god knows when,
> though), I recommend we use our own solution for the time being and
> eventually switch to the native one.
>
>
>>
>> 4. Currently, I store everything as strings, mimicking what QSettings
>> does. Dconf, however, is aware of different data types. So integers
>> and some other types can actually be stored in their binary forms
>> directly rather than all converted to strings. As a proof of concept,
>> I did not do it and just convert everything to strings for ease of
>> implementation. Please feel free to fix this part.
>>
>> Thanks
>>
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>