stop using external hash programs, since cryptonite is faster

In 2013, I wrote "Cryptohash benchmarks 90 to 101% faster than external
hashers". Re-benchmarking today, I found cryptonite's sha256 consistently
outperformed coreutils by 10% for large files. Tested 10 mb, 100 mb, 1 gb
files with both sha256 and sha512. And for smaller files, the external
process startup time swamps the hash time.

Perhaps cryptonite has improved. Or it could just do better on my
current CPU Intel(R) Pentium(R) CPU 4410Y @ 1.50GHz). Anyway, even if cryptonite
is slower in some situations, seems likely it would only be marginally slower;
it's got the same class of highly optimised C code under the hood as coreutils.
The main difference between the two sha256 implementations seems to be
how much of the inner loop they unroll..

This commit was sponsored by Henrik Riomar on Patreon.

Build/BundledPrograms.hs

@@ -75,13 +75,8 @@ preferredBundledPrograms = catMaybes
 	, BuildInfo.lsof
 	, BuildInfo.gcrypt
 #ifndef mingw32_HOST_OS
-	-- All these utilities are included in git for Windows
+	-- These utilities are included in git for Windows
 	, ifset BuildInfo.curl "curl"
-	, BuildInfo.sha1
-	, BuildInfo.sha256
-	, BuildInfo.sha512
-	, BuildInfo.sha224
-	, BuildInfo.sha384
 	, Just "cp"
 #endif
 #ifdef linux_HOST_OS

Build/Configure.hs

@@ -7,7 +7,6 @@ module Build.Configure where
 import Build.TestConfig
 import Build.Version
 import Utility.SafeCommand
-import Utility.ExternalSHA
 import Utility.Env.Basic
 import qualified Git.Version
 import Utility.Directory
@@ -38,38 +37,8 @@ tests =
 	, TestCase "lsof" $ findCmdPath "lsof" "lsof"
 	, TestCase "git-remote-gcrypt" $ findCmdPath "gcrypt" "git-remote-gcrypt"
 	, TestCase "ssh connection caching" getSshConnectionCaching
-	] ++ shaTestCases
-	[ (1, "da39a3ee5e6b4b0d3255bfef95601890afd80709")
-	, (256, "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855")
-	, (512, "cf83e1357eefb8bdf1542850d66d8007d620e4050b5715dc83f4a921d36ce9ce47d0d13c5d85f2b0ff8318d2877eec2f63b931bd47417a81a538327af927da3e")
-	, (224, "d14a028c2a3a2bc9476102bb288234c415a2b01f828ea62ac5b3e42f")
-	, (384, "38b060a751ac96384cd9327eb1b1e36a21fdb71114be07434c0cc7bf63f6e1da274edebfe76f65fbd51ad2f14898b95b")
 	]
 
-{- shaNsum are the program names used by coreutils. Some systems
- - install these with 'g' prefixes.
- -
- - On some systems, shaN is used instead, but on other
- - systems, it might be "hashalot", which does not produce
- - usable checksums. Only accept programs that produce
- - known-good hashes when run on files. -}
-shaTestCases :: [(Int, String)] -> [TestCase]
-shaTestCases l = map make l
-  where
-	make (n, knowngood) = TestCase key $ 
-		Config key . MaybeStringConfig <$> search (shacmds n)
-	  where
-		key = "sha" ++ show n
-		search [] = return Nothing
-		search (c:cmds) = do
-			sha <- externalSHA c n "/dev/null"
-			if sha == Right knowngood
-				then return $ Just c
-				else search cmds
-	
-	shacmds n = concatMap (\x -> [x, 'g':x]) $
-		map (\x -> "sha" ++ show n ++ x) ["sum", ""]
-
 tmpDir :: String
 tmpDir = "tmp"
 
@@ -128,8 +97,6 @@ androidConfig c = overrides ++ filter (not . overridden) c
 	overrides = 
 		[ Config "cp_reflink_auto" $ BoolConfig False
 		, Config "curl" $ BoolConfig False
-		, Config "sha224" $ MaybeStringConfig Nothing
-		, Config "sha384" $ MaybeStringConfig Nothing
 		]
 	overridden (Config k _) = k `elem` overridekeys
 	overridekeys = map (\(Config k _) -> k) overrides