Track file content fingerprints alongside loaded modules

cryptol.cabal

@@ -47,6 +47,7 @@ library
                        bytestring        >= 0.10,
                        array             >= 0.4,
                        containers        >= 0.5,
+                       cryptohash-sha1   >= 0.11 && < 0.12,
                        deepseq           >= 1.3,
                        directory         >= 1.2.2.0,
                        filepath          >= 1.3,
@@ -100,6 +101,7 @@ library
                        Cryptol.ModuleSystem,
                        Cryptol.ModuleSystem.Base,
                        Cryptol.ModuleSystem.Env,
+                       Cryptol.ModuleSystem.Fingerprint,
                        Cryptol.ModuleSystem.Interface,
                        Cryptol.ModuleSystem.Monad,
                        Cryptol.ModuleSystem.Name,

src/Cryptol/ModuleSystem/Base.hs

@@ -15,6 +15,7 @@
 module Cryptol.ModuleSystem.Base where
 
 import Cryptol.ModuleSystem.Env (DynamicEnv(..), deIfaceDecls)
+import Cryptol.ModuleSystem.Fingerprint
 import Cryptol.ModuleSystem.Interface
 import Cryptol.ModuleSystem.Monad
 import Cryptol.ModuleSystem.Name (Name,liftSupply,PrimMap)
@@ -48,13 +49,12 @@ import Cryptol.Prelude (writePreludeContents)
 
 import Cryptol.Transform.MonoValues (rewModule)
 
-import Control.DeepSeq
 import qualified Control.Exception as X
 import Control.Monad (unless,when)
+import qualified Data.ByteString as B
 import Data.Maybe (fromMaybe)
 import Data.Monoid ((<>))
-import           Data.Text(Text)
-import qualified Data.Text.IO as T
+import Data.Text.Encoding (decodeUtf8')
 import System.Directory (doesFileExist, canonicalizePath)
 import System.FilePath ( addExtension
                        , isAbsolute
@@ -105,23 +105,28 @@ noPat a = do
 
 -- Parsing ---------------------------------------------------------------------
 
-parseModule :: FilePath -> ModuleM (P.Module PName)
+parseModule :: FilePath -> ModuleM (Fingerprint, P.Module PName)
 parseModule path = do
 
-  e <- io $ X.try $ do
-    bytes <- T.readFile path
-    return $!! bytes
-  bytes <- case (e :: Either X.IOException Text) of
+  bytesRes <- io (X.try (B.readFile path))
+
+  bytes <- case bytesRes of
     Right bytes -> return bytes
     Left exn | IOE.isDoesNotExistError exn -> cantFindFile path
              | otherwise                   -> otherIOError path exn
 
+  txt <- case decodeUtf8' bytes of
+    Right txt -> return txt
+    Left e    -> badUtf8 path e
+
   let cfg = P.defaultConfig
               { P.cfgSource  = path
               , P.cfgPreProc = P.guessPreProc path
               }
-  case P.parseModule cfg bytes of
-    Right pm -> return pm
+
+  case P.parseModule cfg txt of
+    Right pm -> let fp = fingerprint bytes
+                in fp `seq` return (fp, pm)
     Left err -> moduleParseError path err
 
 
@@ -132,7 +137,7 @@ loadModuleByPath :: FilePath -> ModuleM T.Module
 loadModuleByPath path = withPrependedSearchPath [ takeDirectory path ] $ do
   let fileName = takeFileName path
   foundPath <- findFile fileName
-  pm <- parseModule foundPath
+  (fp, pm) <- parseModule foundPath
   let n = thing (P.mName pm)
 
   -- Check whether this module name has already been loaded from a different file
@@ -142,7 +147,7 @@ loadModuleByPath path = withPrependedSearchPath [ takeDirectory path ] $ do
   path' <- io $ canonicalizePath foundPath
   case lookupModule n env of
     -- loadModule will calculate the canonical path again
-    Nothing -> doLoadModule (FromModule n) foundPath pm
+    Nothing -> doLoadModule (FromModule n) foundPath fp pm
     Just lm
      | path' == loaded -> return (lmModule lm)
      | otherwise       -> duplicateModuleName n path' loaded
@@ -159,16 +164,18 @@ loadModuleFrom isrc =
        Nothing ->
          do path <- findModule n
             errorInFile path $
-              do pm <- parseModule path
-                 m  <- doLoadModule isrc path pm
+              do (fp, pm) <- parseModule path
+                 m        <- doLoadModule isrc path fp pm
                  return (path,m)
 
 -- | Load dependencies, typecheck, and add to the eval environment.
-doLoadModule :: ImportSource ->
-              FilePath ->
-              P.Module PName ->
-              ModuleM T.Module
-doLoadModule isrc path pm0 =
+doLoadModule ::
+  ImportSource ->
+  FilePath ->
+  Fingerprint ->
+  P.Module PName ->
+  ModuleM T.Module
+doLoadModule isrc path fp pm0 =
   loading isrc $
   do let pm = addPrelude pm0
      loadDeps pm
@@ -180,7 +187,7 @@ doLoadModule isrc path pm0 =
      -- extend the eval env, unless a functor.
      unless (T.isParametrizedModule tcm) $ modifyEvalEnv (E.moduleEnv tcm)
      canonicalPath <- io (canonicalizePath path)
-     loadedModule path canonicalPath tcm
+     loadedModule path canonicalPath fp tcm
 
      return tcm
   where

src/Cryptol/ModuleSystem/Env.hs

@@ -18,6 +18,7 @@ import Paths_cryptol (getDataDir)
 #endif
 
 import Cryptol.Eval (EvalEnv)
+import Cryptol.ModuleSystem.Fingerprint
 import Cryptol.ModuleSystem.Interface
 import Cryptol.ModuleSystem.Name (Supply,emptySupply)
 import qualified Cryptol.ModuleSystem.NamingEnv as R
@@ -248,13 +249,14 @@ instance Monoid LoadedModules where
   mappend l r = l <> r
 
 data LoadedModule = LoadedModule
-  { lmName      :: ModName
-  , lmFilePath  :: FilePath
+  { lmName              :: ModName
+  , lmFilePath          :: FilePath
     -- ^ The file path used to load this module (may not be canonical)
-  , lmCanonicalPath :: FilePath
+  , lmCanonicalPath     :: FilePath
     -- ^ The canonical version of the path of this module
-  , lmInterface :: Iface
-  , lmModule    :: T.Module
+  , lmInterface         :: Iface
+  , lmModule            :: T.Module
+  , lmFingerprint       :: Fingerprint
   } deriving (Show, Generic, NFData)
 
 -- | Has this module been loaded already.
@@ -275,8 +277,8 @@ lookupModule mn me = search lmLoadedModules `mplus` search lmLoadedParamModules
 -- | Add a freshly loaded module.  If it was previously loaded, then
 -- the new version is ignored.
 addLoadedModule ::
-  FilePath -> FilePath -> T.Module -> LoadedModules -> LoadedModules
-addLoadedModule path canonicalPath tm lm
+  FilePath -> FilePath -> Fingerprint -> T.Module -> LoadedModules -> LoadedModules
+addLoadedModule path canonicalPath fp tm lm
   | isLoaded (T.mName tm) lm  = lm
   | T.isParametrizedModule tm = lm { lmLoadedParamModules = loaded :
                                                 lmLoadedParamModules lm }
@@ -284,11 +286,12 @@ addLoadedModule path canonicalPath tm lm
                                           lmLoadedModules lm ++ [loaded] }
   where
   loaded = LoadedModule
-    { lmName      = T.mName tm
-    , lmFilePath  = path
-    , lmCanonicalPath = canonicalPath
-    , lmInterface = genIface tm
-    , lmModule    = tm
+    { lmName            = T.mName tm
+    , lmFilePath        = path
+    , lmCanonicalPath   = canonicalPath
+    , lmInterface       = genIface tm
+    , lmModule          = tm
+    , lmFingerprint     = fp
     }
 
 -- | Remove a previously loaded module.

src/Cryptol/ModuleSystem/Fingerprint.hs

@@ -0,0 +1,40 @@
+-- |
+-- Module      :  Cryptol.ModuleSystem.Fingerprint
+-- Copyright   :  (c) 2019 Galois, Inc.
+-- License     :  BSD3
+-- Maintainer  :  cryptol@galois.com
+-- Stability   :  provisional
+-- Portability :  portable
+
+module Cryptol.ModuleSystem.Fingerprint
+  ( Fingerprint
+  , fingerprint
+  , fingerprintFile
+  ) where
+
+import Control.DeepSeq          (NFData (rnf))
+import Crypto.Hash.SHA1         (hash)
+import Data.ByteString          (ByteString)
+import System.IO.Error          (IOError)
+import Control.Exception        (try)
+import qualified Data.ByteString as B
+
+newtype Fingerprint = Fingerprint ByteString
+  deriving (Eq, Show)
+
+instance NFData Fingerprint where
+  rnf (Fingerprint fp) = rnf fp
+
+-- | Compute a fingerprint for a bytestring.
+fingerprint :: ByteString -> Fingerprint
+fingerprint = Fingerprint . hash
+
+-- | Attempt to compute the fingerprint of the file at the given path.
+-- Returns 'Nothing' in the case of an error.
+fingerprintFile :: FilePath -> IO (Maybe Fingerprint)
+fingerprintFile path =
+  do res <- try (B.readFile path)
+     return $!
+       case res :: Either IOError ByteString of
+         Left{}  -> Nothing
+         Right b -> Just $! fingerprint b

src/Cryptol/ModuleSystem/Monad.hs

@@ -16,6 +16,7 @@ import           Cryptol.Eval (EvalEnv,EvalOpts(..))
 
 import qualified Cryptol.Eval.Monad           as E
 import           Cryptol.ModuleSystem.Env
+import           Cryptol.ModuleSystem.Fingerprint
 import           Cryptol.ModuleSystem.Interface
 import           Cryptol.ModuleSystem.Name (FreshM(..),Supply)
 import           Cryptol.ModuleSystem.Renamer
@@ -37,6 +38,7 @@ import Control.Monad.IO.Class
 import Control.Exception (IOException)
 import Data.Function (on)
 import Data.Maybe (isJust)
+import Data.Text.Encoding.Error (UnicodeException)
 import MonadLib
 
 import GHC.Generics (Generic)
@@ -76,6 +78,8 @@ data ModuleError
     -- ^ Unable to find the module given, tried looking in these paths
   | CantFindFile FilePath
     -- ^ Unable to open a file
+  | BadUtf8 FilePath UnicodeException
+    -- ^ Bad UTF-8 encoding in while decoding this file
   | OtherIOError FilePath IOException
     -- ^ Some other IO error occurred while reading this file
   | ModuleParseError FilePath Parser.ParseError
@@ -113,6 +117,7 @@ instance NFData ModuleError where
   rnf e = case e of
     ModuleNotFound src path              -> src `deepseq` path `deepseq` ()
     CantFindFile path                    -> path `deepseq` ()
+    BadUtf8 path ue                      -> rnf (path, ue)
     OtherIOError path exn                -> path `deepseq` exn `seq` ()
     ModuleParseError source err          -> source `deepseq` err `deepseq` ()
     RecursiveModules mods                -> mods `deepseq` ()
@@ -146,6 +151,10 @@ instance PP ModuleError where
       text "[error]" <+>
       text "can't find file:" <+> text path
 
+    BadUtf8 path _ue ->
+      text "[error]" <+>
+      text "bad utf-8 encoding:" <+> text path
+
     OtherIOError path exn ->
       hang (text "[error]" <+>
             text "IO error while loading file:" <+> text path <.> colon)
@@ -198,6 +207,9 @@ moduleNotFound name paths = ModuleT (raise (ModuleNotFound name paths))
 cantFindFile :: FilePath -> ModuleM a
 cantFindFile path = ModuleT (raise (CantFindFile path))
 
+badUtf8 :: FilePath -> UnicodeException -> ModuleM a
+badUtf8 path ue = ModuleT (raise (BadUtf8 path ue))
+
 otherIOError :: FilePath -> IOException -> ModuleM a
 otherIOError path exn = ModuleT (raise (OtherIOError path exn))
 
@@ -444,10 +456,10 @@ unloadModule rm = ModuleT $ do
   env <- get
   set $! env { meLoadedModules = removeLoadedModule rm (meLoadedModules env) }
 
-loadedModule :: FilePath -> FilePath -> T.Module -> ModuleM ()
-loadedModule path canonicalPath m = ModuleT $ do
+loadedModule :: FilePath -> FilePath -> Fingerprint -> T.Module -> ModuleM ()
+loadedModule path canonicalPath fp m = ModuleT $ do
   env <- get
-  set $! env { meLoadedModules = addLoadedModule path canonicalPath m (meLoadedModules env) }
+  set $! env { meLoadedModules = addLoadedModule path canonicalPath fp m (meLoadedModules env) }
 
 modifyEvalEnv :: (EvalEnv -> E.Eval EvalEnv) -> ModuleM ()
 modifyEvalEnv f = ModuleT $ do