[MonoDevelop] Requesting write permission

[Casey Marshall]

I'm starting to look into how to support automatically asking for write 
permission when MonoDevelop saves files, which might mean asking the 
version control addin to open the file for editing. It looks simple 
enough, to put calls to FileService.RequestFileEdit in the appropriate 
places before trying to overwrite files.

My question, though, is where the best place for these calls should be? 
Should it be at the high level -- i.e., for commands like "File->Save," 
-- or does it make more sense at the low level, i.e., in each actual 
file format implementation that does the writing? The former seems to 
make more sense, since it captures more things with less code, but it 
isn't clear if it's appropriate to introduce file checks at so high a level.

Thanks.