From a0b040524a595c16ddb2dbead205ca8ccb6890aa Mon Sep 17 00:00:00 2001 From: Joey Hess Date: Sun, 17 Oct 2010 00:33:05 -0400 Subject: remove checksum from WORM with size and mtime in the key, it's redundant --- Backend/WORM.hs | 18 +++++------------- 1 file changed, 5 insertions(+), 13 deletions(-) (limited to 'Backend/WORM.hs') diff --git a/Backend/WORM.hs b/Backend/WORM.hs index 7e86d4d24..463b0ac8e 100644 --- a/Backend/WORM.hs +++ b/Backend/WORM.hs @@ -6,7 +6,6 @@ module Backend.WORM (backend) where import Control.Monad.State import System.FilePath import System.Posix.Files -import Data.Digest.Pure.SHA -- slow, but we only checksum filenames import qualified Data.ByteString.Lazy.Char8 as B import qualified Backend.File @@ -18,25 +17,18 @@ backend = Backend.File.backend { getKey = keyValue } --- A SHA1 of the basename of the filename, plus the file size and --- modification time, is used as the unique part of the key. That --- allows multiple files with the same names to have different keys, +-- The key is formed from the file size, modification time, and the +-- basename of the filename. +-- +-- That allows multiple files with the same names to have different keys, -- while also allowing a file to be moved around while retaining the -- same key. --- --- The file size and modification time are also included in the key, --- unhashed. This could be used as a sanity check. --- --- The basename of the filename is also included in the key, so it's clear --- what the original filename was when a user sees the value. keyValue :: FilePath -> Annex (Maybe Key) keyValue file = do stat <- liftIO $ getFileStatus file return $ Just $ Key ((name backend), key stat) where - key stat = (checksum $ uniqueid stat) ++ sep ++ - uniqueid stat ++ sep ++ base - checksum s = show $ sha1 $ B.pack s + key stat = uniqueid stat ++ sep ++ base uniqueid stat = (show $ modificationTime stat) ++ sep ++ (show $ fileSize stat) base = takeFileName file -- cgit v1.2.3