[Sugar-devel] Datastore API changes

[Sascha Silbe]

On Thu, Jul 02, 2009 at 04:14:36PM +0200, Tomeu Vizoso wrote:

> Also copying a file can be quite expensive, specially on the XO-1.
That's the reason for these requirement:

    * data should be provided on the same FS as the Journal (for 
hardlinking)
    * activities must not modify the entry they submit to data store 
before it has been commited (and the activity notified about that)
        * Python API may copy file if activity indicates it doesn't 
fulfill this requirement
    * activities must not modify the entry they received from datastore
        * Python API may copy file if activity indicates it doesn't 
fulfill this requirement
    * VCS backend must not modify files that have been provided as input 
(for commit) or checked out => link-breaking
        * if the VCS doesn't support this, the backend needs to implement 
it by copying

I'm going to make extensive use of hardlinking. While a two-edged sword 
(if the activity retains a directory entry to the file it can 
potentially change the in-datastore "copy") it can also greatly reduce 
the amount of copying to be done.

CU Sascha

-- 
http://sascha.silbe.org/
http://www.infra-silbe.de/
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