[pulseaudio-discuss] [RFC] Changing the way our saved database files are stored from blob to tagstruct.

[Colin Guthrie]

'Twas brillig, and Colin Guthrie at 06/06/11 19:33 did gyre and gimble:
> Hi,
> 
> I'm intending on changing module-device-restore to store some elements
> of sink proplists (for Arun and Pierre's passthrough work in order to
> allow the user to specify what formats his receiver supports).
> 
> In order to do that, I need to be able to store an arbitrary sized chunk
> of data in the database. At present, all the files that use it are based
> on fixed sizes.
> 
> So in order to make this neater, I've converted the internal database
> reading/writing to use tagstructs. This allows us to version the data
> stored in the same way our protocol is versioned (while this isn't
> really awesome from a code perspective, at least it's extensible which
> is nice). At present when we change something we have to invalidate all
> old data. This way we can save some of it at least if we want to.
> 
> Of course during this transition, it's much simpler to just trash the
> old data and start again which is what I've done. If people are super
> opposed to this, I guess we could load the old format and transition it
> to the new format... let me know your opinions on this. Personally I
> don't really mind about losing the data this once (especially as we're
> moving to 1.0)
> 
> 
> The memory management is a little more complicated now (the entries are
> no longer stack based as they are more dynamic), but otherwise the
> principles are identical. There will be marginally greater overhead but
> this isn't something that is done super often so I think that's permissible.
> 
> Please check the attached patch (particularly for memory leaks!)

OK, I've updated this patch here:
http://colin.guthr.ie/git/pulseaudio/log/?h=master-sv-tagstuct

This includes also another patch on for a protocol extension to
module-device-restore to allow us to save the formats it supports (this
will allow for manual configuration of receiver formats for passthrough).

I've also added support for loading the legacy formats. I did this as a
separate commit as it should hopefully be easier to revert at a later date.

If no objections on principle here I plan to merge this when I merge the
source-output volume branch which I hope to do soon so we can get some
test tarballs out and make a call for testing.

Cheers

Col

-- 

Colin Guthrie
gmane(at)colin.guthr.ie
http://colin.guthr.ie/

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