[sugar] Sharing data between activities.

Carlos Neves cn
Thu Aug 23 21:58:41 EDT 2007

Ivan Krsti? wrote:
> On Aug 23, 2007, at 7:20 PM, Carlos Neves wrote:
>> This 'My Own Image' should not pose problems in the future, but the
>> shared stuff in the activity will, because activities will no longer
>> have access to other activity dirs, right?
> Right.
>> So, my solution would be to add some post installation script for the
>> code sharing activity (that might end up being just a placeholder
>> activity, always invisible) and have that create hard links on some
>> ~olpc/.sugar/default/$(OUR_PREFIX} directory.
>> Would this work?
> No.
>> Can I assume the activities will have access to
>> ~olpc/.sugar?
> No.
>> Will they have write access to all of it or will there be
>> another place to write files on the filesystem?
> You'll get chrooted into a activity-specific path with a few writable 
> and few immutable folders. You won't get a view of the FS outside of 
> that.
So the only writable common ground will be the datastore/journal? Isn't 
that a bit harsh? I mean, we can assert that some places are write only, 
and I know this whole home/my documents assumption is product of (bad) 
habits created from years of using computers, and the XO is not targeted 
for people like me. I know that there is a new usage paradigm on the 
make here but shouldn't there be some kind of file based, invisible 
unless searched specifically (not the journal) place for generic data, 
i.e. files?

Imagine I want to create an sqlite db. And I have interest in accessing 
that from two separate activities. Is this an impossible task given the 
security being implemented?
> I think you're attempting to solve a non-problem, however. The 
> activity installation system will take care of not downloading (and 
> not storing) duplicate information, based on file hashes. Making three 
> activities that all incorporate the same shared files is sufficient; 
> the OS will make sure no space is being wasted by storing multiple 
> copies. If you really want to manage things yourself, you'll need to 
> package up all three activities as one activity whose frontend is the 
> launcher.
But Launchers are one thing so strongly opposed by many. You are 
puzzling me, what is your opinion on having a Launcher frontend for 
multiple activities (ignore the multiple things under the same activity 
x multiple separate activities argument).
> -- 
> Ivan Krsti? <krstic at solarsail.hcs.harvard.edu> | http://radian.org

Carlos Neves
cn at sueste.net

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