histedit: factor most commit creation in a function Later commits add two important items to histedit: - Obsolescence cycle prevention - Proper phase conservation Those logics must be applied to all simple operations (pick, edit, mess) and will require verbose code. So we introduce a new function that will provide an entry point for this new. logic. The function build a closure to have a clear distinction between commit arguments and data provided to the function to fulfil its logic.

store: switch to C-based hashed path encoding

pathencode: implement both basic and hashed encoding in C

pathencode: implement hashed encoding in C This will be used by an upcoming patch.

pathencode: implement the "mangling" part of hashed encoding in C This will be used by an upcoming patch.

pathencode: add a SHA-1 hash function This will be used by an upcoming patch. This calls out to the Python hash implementation. An earlier version of this function implemented SHA-1 directly, but the amount of extra code didn't seem like a good tradeoff compared to the small big-picture increase in performance (long paths are uncommon).