filestore
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jgm
save method should return IO RevisionId
It would be handy if save could return the RevisionId it just saved the FilePath at, rather than requiring that you immediately call latest for that same FilePath.
I mention this because I'd like to write a gitlib module for FileStore, and the division of information between save and latest like this is inefficient if you are writing code that persists the RevisionId information elsewhere after each save. The only way to answer such a query in O(1) would require keeping state information in gitlib about the most recent commit, which it does not do.
I would have no problem with the suggested API change. It would require modifying gitSave, darcsSave, etc. so that these functions called gitLatestRevId, darcsLatestRevId, etc. after saving. This would cause a small slowdown, but only on saving, so I don't think it's a big deal. (And presumably there would be no performance hit with your gitlib backend -- which I'm very excited to hear about.)
Because the proposed change just replaces a () return value, I don't think it would have any impact on existing code that uses filestore.
+++ John Wiegley [Mar 06 13 00:52 ]:
It would be handy if save could return the RevisionId it just saved the FilePath at, rather than requiring that you immediately call latest for that same FilePath.
I mention this because I'd like to write a gitlib module for FileStore, and the division of information between save and latest like this is inefficient if you are writing code that persists the RevisionId information elsewhere after each save. The only way to answer such a query in O(1) would require keeping state information in gitlib about the most recent commit, which it does not do.
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References
- https://github.com/jgm/filestore/issues/7
I suppose one way to make everyone happy would be to change save to return the RevisionId, and then have save_ which would have the current save signature.
Let's just keep it simple and change save.
+++ John Wiegley [Mar 06 13 09:08 ]:
I suppose one way to make everyone happy would be to change save to return the RevisionId, and then have save_ which would have the current save signature.
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References
- https://github.com/jgm/filestore/issues/7#issuecomment-14512771
Since I'm worried about performance, I'm not going to make this change now. But if you come up with a libgit backend, I think I'll be okay with it then.
@jgm Sorry for the delay, but release schedules demand that I back-burner creating that backend for a little bit. Good news is that gitlib has come a long way in the past month, though, so I think creating it should be trivial now.