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content-store (empty) → 0.1.0

raw patch · 10 files changed

+1329/−0 lines, 10 filesdep +aesondep +basedep +bytestringsetup-changed

Dependencies added: aeson, base, bytestring, cond, conduit, conduit-combinators, conduit-extra, content-store, cryptonite, directory, filepath, hspec, htoml, memory, monad-control, mtl, resourcet, temporary, text, transformers, transformers-base, unix

Files

+ ChangeLog.md view
@@ -0,0 +1,3 @@+## 0.1.0++* Initial release.
+ Data/ContentStore.hs view
@@ -0,0 +1,482 @@+{-# LANGUAGE FlexibleContexts #-}+{-# LANGUAGE GeneralizedNewtypeDeriving #-}+{-# LANGUAGE LambdaCase #-}+{-# LANGUAGE MultiParamTypeClasses #-}+{-# LANGUAGE OverloadedStrings #-}+{-# LANGUAGE RankNTypes #-}+{-# LANGUAGE RecordWildCards #-}+{-# LANGUAGE TypeFamilies #-}+{-# LANGUAGE UndecidableInstances #-}++-- |+-- Module: Data.ContentStore+-- Copyright: (c) 2017 Red Hat, Inc.+-- License: LGPL+--+-- Maintainer: https://github.com/weldr+-- Stability: alpha+-- Portability: portable+--+-- Create content stores, put objects into them, and retrieve objects from them.++module Data.ContentStore(ContentStore,+                         CsError(..),+                         CsMonad,+                         runCsMonad,+                         contentStoreDigest,+                         contentStoreValid,+                         fetchByteString,+                         fetchByteStringC,+                         fetchFile,+                         fetchLazyByteString,+                         fetchLazyByteStringC,+                         mkContentStore,+                         openContentStore,+                         storeByteString,+                         storeByteStringC,+                         storeByteStringSink,+                         storeDirectory,+                         storeFile,+                         storeLazyByteString,+                         storeLazyByteStringC,+                         storeLazyByteStringSink)+ where++import           Conduit+import           Control.Conditional(ifM, unlessM, whenM)+import           Control.Monad((>=>), forM, forM_, join, void)+import           Control.Monad.Base(MonadBase(..))+import           Control.Monad.Except(ExceptT, MonadError, catchError, runExceptT, throwError)+import           Control.Monad.IO.Class(MonadIO, liftIO)+import           Control.Monad.Trans.Control(MonadBaseControl(..))+import           Control.Monad.Trans.Resource(MonadResource, MonadThrow, ResourceT, runResourceT)+import qualified Data.ByteString as BS+import qualified Data.ByteString.Lazy as LBS+import           Data.Maybe(isNothing)+import           System.Directory(canonicalizePath, createDirectoryIfMissing, doesDirectoryExist, doesFileExist, listDirectory, removeFile, renameFile)+import           System.FilePath((</>))+import           System.IO(Handle, SeekMode(..))+import           System.IO.Temp(openTempFile)+import           System.Posix.IO(FileLock, LockRequest(..), OpenMode(..), closeFd, defaultFileFlags, fdToHandle, getLock, handleToFd, openFd, setLock, waitToSetLock)++import Data.ContentStore.Config(Config(..), defaultConfig, readConfig, writeConfig)+import Data.ContentStore.Digest++-- | The ContentStore is an opaque type that contains various pieces of information+-- used to describe an on-disk content store.  Values of this type are constructed+-- via 'mkContentStore' and 'openContentStore', depending on which operation you+-- need to perform.  Users should not need to concern themselves with the internals+-- of this type.+data ContentStore = ContentStore {+    csConfig :: Config,+    csRoot :: FilePath,+    csHash :: DigestAlgorithm+ }++-- | A type to represent various errors that can occur during content store operations.+data CsError =+    -- | Miscellaneous, uncategorized errors.  The string is the exact error message.+    CsError String+    -- | An object with this digest already exists in the content store.  This error+    -- is not typically raised during write operations, because attempting to write+    -- the same thing twice is not really an error.+  | CsErrorCollision String+    -- | A parse error occurred reading the content store's internal config file.  This+    -- generally represents either a programming error or that someone has been modifying+    -- the internals.  The string contains the error message.+  | CsErrorConfig String+    -- | The content store directory is invalid.  This usually occurs because some file+    -- or directory is missing.  The string is the name of what is missing.+  | CsErrorInvalid String+    -- | The content store does not exist.+  | CsErrorMissing+    -- | The requested object does not exist in the content store.  The string contains+    -- the object digest requested.+  | CsErrorNoSuchObject String+    -- | The hashing algorithm is not supported by the content store.  Not all possible+    -- algorithms are supported.  The string contains the name of the algorithm requested.+  | CsErrorUnsupportedHash String+ deriving (Eq, Show)++-- | Working with a 'ContentStore' requires a lot of behind-the-scenes management of+-- 'ResourceT', 'ExceptT', and 'IO'.  Along with 'runCsMonad', this provides a type+-- and function for doing much of that management for you.  These two can be used like+-- so:+--+-- > result <- runCsMonad $ do+-- >     cs <- mkContentStore "/tmp/cs.repo"+-- >     storeDirectory cs "/tmp/test-data"+-- >+-- > case result of+-- >     Left e  -> print e+-- >     Right d -> do putStrLn "Stored objects: "+-- >                   mapM_ print d+--+-- Most functions in this module do not explicitly require use of 'CsMonad', but any+-- that have a return type including 'm' can be run inside it.+newtype CsMonad a = CsMonad { getCsMonad :: ResourceT (ExceptT CsError IO) a }+ deriving (Applicative, Functor, Monad, MonadBase IO, MonadError CsError, MonadIO, MonadResource, MonadThrow)++instance MonadBaseControl IO CsMonad where+    type StM CsMonad a = StM (ResourceT (ExceptT CsError IO)) a+    liftBaseWith f = CsMonad $ liftBaseWith $ \r -> f (r . getCsMonad)+    restoreM = CsMonad . restoreM++-- | See the documentation for 'CsMonad'.+runCsMonad :: CsMonad a -> IO (Either CsError a)+runCsMonad x = runExceptT $ runResourceT $ getCsMonad x++csSubdirs :: [String]+csSubdirs = ["objects", "tmp", "lock"]++--+-- PRIVATE FUNCTIONS+--++-- Objects are stored in the content store in a subdirectory within the objects directory.+-- This function makes sure that path exists.+ensureObjectSubdirectory :: ContentStore -> String -> IO ()+ensureObjectSubdirectory cs subdir =+    createDirectoryIfMissing True (objectSubdirectoryPath cs subdir)++-- Assemble the directory path where an object will be stored.+objectSubdirectoryPath :: ContentStore -> String -> FilePath+objectSubdirectoryPath ContentStore{..} subdir =+    csRoot </> "objects" </> subdir++-- Where in the content store should an object be stored?  This function takes the calculated+-- digest of the object and splits it into a subdirectory and the filename within that+-- directory.+--+-- This function is used when objects are on the way into the content store.+storedObjectDestination :: ObjectDigest -> (String, String)+storedObjectDestination = storedObjectLocation . toHex++-- Where in the content store is an object stored?  This function takes the digest of the object+-- that we got from somewhere outside of content store code and splits it into a subdirectory+-- and the filename within that directory.+--+-- This function is used when objects are on the way out of the content store.+storedObjectLocation :: String -> (String, String)+storedObjectLocation = splitAt 2++-- Given a content store and a digest, try to find the file containing that object.  This+-- does not read the object off the disk.+findObject :: (MonadError CsError m, MonadIO m) => ContentStore -> ObjectDigest -> m FilePath+findObject cs digest = do+    let (subdir, filename) = storedObjectDestination digest+        path               = objectSubdirectoryPath cs subdir </> filename++    ifM (liftIO $ doesFileExist path)+        (return path)+        (throwError $ CsErrorNoSuchObject $ toHex digest)++startStore :: ContentStore -> IO (FilePath, Handle)+startStore ContentStore{..} = do+    -- Acquire the global lock to prevent a race between creating the tmp file and locking it.+    (path, fd) <- withGlobalLock csRoot $ do+        -- Create a new file in the tmp directory+        (path, handle) <- openTempFile (csRoot </> "tmp") "import"++        -- NB: this step closes handle+        fd <- handleToFd handle++        -- Lock the file+        setLock fd fullLock++        return (path, fd)++    -- Reopen the locked fd as a handle and return+    handle' <- fdToHandle fd+    return (path, handle')++finishStore :: ContentStore -> (FilePath, Handle) -> ObjectDigest -> IO ()+finishStore cs (tmpPath, handle) digest = do+    let (subdir, filename) = storedObjectDestination digest+    let path               = objectSubdirectoryPath cs subdir </> filename++    ensureObjectSubdirectory cs subdir++    -- Move the file into the object directory+    renameFile tmpPath path++    -- Unlock the file and close the descriptor+    fd <- handleToFd handle+    setLock fd fullUnlock+    closeFd fd++-- This stores an object that is already (or can be) fully loaded into memory+doStore :: MonadIO m => ContentStore -> (a -> ObjectDigest) -> (Handle -> Consumer a IO ()) -> Conduit a m ObjectDigest+doStore cs hasher writer = awaitForever $ \object -> do+    let digest             = hasher object+    let (subdir, filename) = storedObjectDestination digest+        path               = objectSubdirectoryPath cs subdir </> filename++    liftIO $ ensureObjectSubdirectory cs subdir++    -- Only store the object if it does not already exist in the content store.+    -- If it's already there, just return the digest.+    liftIO $ unlessM (doesFileExist path) $ do+        (tmpPath, handle) <- startStore cs+        void $ runConduit $ yield object .| writer handle+        finishStore cs (tmpPath, handle) digest++    yield digest++-- Stream data into the content-store without loading all of it at once+doStoreSink :: MonadIO m => ContentStore -> (DigestContext -> a -> DigestContext) -> (Handle -> Sink a m ()) -> Sink a m ObjectDigest+doStoreSink cs hasher writer = do+    (tmpPath, handle) <- liftIO $ startStore cs+    let initctx = digestInit $ csHash cs++    -- One sink calculates the digest, the other writes the data to the tmp file+    (_, digest) <- getZipConduit ((,) <$> ZipConduit (writer handle)+                                      <*> ZipConduit (digestSink initctx))++    let (subdir, _) = storedObjectDestination digest++    liftIO $ ensureObjectSubdirectory cs subdir+    liftIO $ finishStore cs (tmpPath, handle) digest++    return digest+ where+    digestSink ctx = await >>= \case+        Nothing    -> return $ digestFinalize ctx+        Just chunk -> digestSink $ hasher ctx chunk++-- lock file management+fullLock :: FileLock+fullLock = (WriteLock, AbsoluteSeek, 0, 0)++fullUnlock :: FileLock+fullUnlock = (Unlock, AbsoluteSeek, 0, 0)++withGlobalLock :: MonadIO m => FilePath -> m a -> m a+withGlobalLock csRoot action = do+    let lockFile = csRoot </> "lock" </> "lockfile"++    -- Create or open the lock file+    fd <- liftIO $ openFd lockFile WriteOnly (Just 0o644) defaultFileFlags++    -- Acquire the lock+    liftIO $ waitToSetLock fd fullLock++    -- Perform the action+    ret <- action++    -- Release the lock+    liftIO $ setLock fd fullUnlock >> closeFd fd++    return ret++-- Cleanup any stale tmp files. These are any files in the tmp directory+-- that are not locked, while the global lock is held.+cleanupTmp :: FilePath -> IO ()+cleanupTmp csRoot = withGlobalLock csRoot $ listDirectory (csRoot </> "tmp") >>= mapM_ cleanupOne+ where+    cleanupOne :: FilePath -> IO ()+    cleanupOne tmpFile = do+        let fullPath = csRoot </> tmpFile+        fd <- openFd fullPath ReadOnly Nothing defaultFileFlags+        whenM (isNothing <$> getLock fd fullLock) $ removeFile fullPath++--+-- PUBLIC FUNCTIONS+--++--+-- CONTENT STORE MANAGEMENT+--++-- | Check that a content store exists and contains everything it's supposed to.  This does+-- not check the validity of all the contents, however.  A 'CsError' will be thrown if there+-- are any problems.  Otherwise, this function returns True.+contentStoreValid :: (MonadError CsError m, MonadIO m) => FilePath -> m Bool+contentStoreValid fp = do+    unlessM (liftIO $ doesDirectoryExist fp) $+        throwError CsErrorMissing++    unlessM (liftIO $ doesFileExist $ fp </> "config") $+        throwError $ CsErrorInvalid "config"++    forM_ csSubdirs $ \subdir ->+        unlessM (liftIO $ doesDirectoryExist $ fp </> subdir) $+            throwError $ CsErrorInvalid subdir++    return True++-- | Return the digest type used by a content store.+contentStoreDigest :: ContentStore -> DigestAlgorithm+contentStoreDigest ContentStore{..} = csHash++-- | Create a new 'ContentStore' on disk, rooted at the path given, and return it as if+-- 'openContentStore' had also been called.  If a content store already exists at the+-- given root and is valid, return that as if 'openContentStore' had been called.+-- Various 'CsError's could be thrown by this process.+mkContentStore :: (MonadError CsError m, MonadIO m) => FilePath -> m ContentStore+mkContentStore fp = do+    path <- liftIO $ canonicalizePath fp++    csExists <- contentStoreValid path `catchError` \_ -> return False+    if csExists then openContentStore path+    else do+        -- Create the required subdirectories.+        mapM_ (\d -> liftIO $ createDirectoryIfMissing True (path </> d))+              csSubdirs++        -- Write a config file.+        liftIO $ writeConfig (path </> "config") defaultConfig++        openContentStore path++-- | Return an already existing 'ContentStore', after checking that it is valid.+-- Various 'CsError's could be thrown by this process.+openContentStore :: (MonadError CsError m, MonadIO m) => FilePath -> m ContentStore+openContentStore fp = do+    path <- liftIO $ canonicalizePath fp++    void $ contentStoreValid path++    liftIO $ cleanupTmp path++    conf <- liftIO (readConfig $ path </> "config") >>= \case+        Left e  -> throwError $ CsErrorConfig (show e)+        Right c -> return c++    let algo = confHash conf++    case getDigestAlgorithm algo of+        Nothing -> throwError $ CsErrorUnsupportedHash (show algo)+        Just da -> return ContentStore { csRoot=path, csConfig=conf, csHash=da }++--+-- STRICT BYTE STRING INTERFACE+--++-- Like headC, but throws a CsError if the stream is empty.  You supply the error message.+headCError :: MonadError CsError m => String -> Consumer a m a+headCError s =+    join $ maybe (throwError $ CsError s) return <$> headC++-- Like headC, but throws a CsErrorNoSuchObject if the stream is empty.  You supply the+-- digest of the object that's missing.+headCMissing :: MonadError CsError m => ObjectDigest -> Consumer a m a+headCMissing digest =+    join $ maybe (throwError $ CsErrorNoSuchObject (show digest)) return <$> headC++-- | Lookup and return some previously stored object as a strict 'ByteString'.  Note that+-- you'll probably need to use 'fromByteString' to produce an 'ObjectDigest' from whatever+-- text or binary representation you've got from the user/mddb/etc.+fetchByteString :: (MonadBaseControl IO m, MonadError CsError m, MonadIO m, MonadThrow m) =>+                   ContentStore     -- ^ An opened 'ContentStore'.+                -> ObjectDigest     -- ^ The 'ObjectDigest' for some stored object.+                -> m BS.ByteString+fetchByteString cs digest =+    runConduitRes (yield digest .| fetchByteStringC cs .| headCMissing digest)++-- | Given an opened 'ContentStore' and a 'Conduit' of 'ObjectDigest's, load each one into+-- a strict 'ByteString' and put it into the conduit.  This is useful for stream many+-- objects out of the content store at a time, like with exporting an RPM or other package+-- format.+fetchByteStringC :: (MonadError CsError m, MonadIO m, MonadResource m) => ContentStore -> Conduit ObjectDigest m BS.ByteString+fetchByteStringC cs = awaitForever $+    findObject cs >=> sourceFile++-- | Store some object into the content store and return its 'ObjectDigest'.  If an object+-- with the same digest already exists in the content store, this is a duplicate.  Simply+-- return the digest of the already stored object and do nothing else.  A 'CsErrorCollision'+-- will NOT be thrown.+storeByteString :: (MonadBaseControl IO m, MonadError CsError m, MonadIO m) =>+                   ContentStore     -- ^ An opened 'ContentStore'.+                -> BS.ByteString    -- ^ An object to be stored, as a strict 'ByteString'.+                -> m ObjectDigest+storeByteString cs bs =+    runConduitRes (yield bs .| storeByteStringC cs .| headCError "Failed to store object")++-- | Like 'storeByteString', but read strict 'ByteString's from a 'Conduit' and put their+-- 'ObjectDigest's into the conduit.  This is useful for storing many objects at a time,+-- like with importing an RPM or other package format.+storeByteStringC :: (MonadError CsError m, MonadIO m) => ContentStore -> Conduit BS.ByteString m ObjectDigest+storeByteStringC cs = doStore cs (digestByteString $ csHash cs) sinkHandle++-- | Read in a 'Conduit' of strict 'ByteString's, store the stream into an object in an+-- already opened 'ContentStore', and return the final digest.  This is useful for+-- storing a stream of data as a single object.+storeByteStringSink :: MonadIO m => ContentStore -> Sink BS.ByteString m ObjectDigest+storeByteStringSink cs = doStoreSink cs digestUpdate sinkHandle++--+-- LAZY BYTE STRING INTERFACE+--++-- | Like 'fetchByteString', but uses lazy 'Data.ByteString.Lazy.ByteString's instead.+fetchLazyByteString :: (MonadBaseControl IO m, MonadError CsError m, MonadIO m, MonadThrow m) =>+                       ContentStore+                    -> ObjectDigest+                    -> m LBS.ByteString+fetchLazyByteString cs digest =+    runConduitRes (yield digest .| fetchLazyByteStringC cs .| headCMissing digest)++-- | Like 'fetchByteStringC', but uses lazy 'Data.ByteString.Lazy.ByteString's instead.+fetchLazyByteStringC :: (MonadError CsError m, MonadIO m, MonadResource m) => ContentStore -> Conduit ObjectDigest m LBS.ByteString+fetchLazyByteStringC cs = awaitForever $+    findObject cs >=> \path -> sourceFile path .| sinkLazy++-- | Like 'storeByteString', but uses lazy 'Data.ByteString.Lazy.ByteString's instead.+storeLazyByteString :: (MonadBaseControl IO m, MonadError CsError m, MonadIO m) =>+                       ContentStore+                    -> LBS.ByteString+                    -> m ObjectDigest+storeLazyByteString cs bs =+    runConduitRes (yield bs .| storeLazyByteStringC cs .| headCError "Failed to store object")++-- | Like 'storeByteStringC', but uses lazy 'Data.ByteString.Lazy.ByteString's instead.+storeLazyByteStringC :: (MonadError CsError m, MonadIO m) => ContentStore -> Conduit LBS.ByteString m ObjectDigest+storeLazyByteStringC cs = doStore cs (digestLazyByteString $ csHash cs) (\h -> mapC LBS.toStrict .| sinkHandle h)++-- | Like 'storeByteStringSink', but uses lazy 'Data.ByteString.Lazy.ByteString's instead.+storeLazyByteStringSink :: MonadIO m => ContentStore -> Sink LBS.ByteString m ObjectDigest+storeLazyByteStringSink cs = doStoreSink cs (LBS.foldlChunks digestUpdate) (\h -> mapC LBS.toStrict .| sinkHandle h)++--+-- DIRECTORY INTERFACE+--++-- | Store all objects in a directory tree in the content store, returning the name and 'ObjectDigest'+-- of each.  Note that directories will not be stored.  The content store only contains things that+-- have content.  If you need to store directory information, that should be handled externally to+-- this module.+storeDirectory :: (MonadBaseControl IO m, MonadError CsError m, MonadIO m, MonadResource m) =>+                  ContentStore                  -- ^ An opened 'ContentStore'.+               -> FilePath                      -- ^ A directory tree containing many objects.+               -> m [(FilePath, ObjectDigest)]+storeDirectory cs fp = do+    entries <- runConduit $ sourceDirectoryDeep False fp .| sinkList+    forM entries $ \entry -> do+        digest <- storeFile cs entry+        return (entry, digest)++--+-- FILE INTERFACE+--++-- | Find some object in the content store and write it to a destination.  If the destination already+-- exists, it will be overwritten.  If the object does not already exist, a 'CsErrorNoSuchObject' will+-- be thrown.+fetchFile :: (MonadBaseControl IO m, MonadError CsError m, MonadIO m, MonadResource m) =>+             ContentStore   -- ^ An opened 'ContentStore'.+          -> ObjectDigest   -- ^ The 'ObjectDigest' of some stored object.+          -> FilePath       -- ^ The destination+          -> m ()+fetchFile cs digest dest =+    runConduitRes $ yield digest .| fetchByteStringC cs .| sinkFile dest++-- | Store an already existing file in the content store, returning its 'ObjectDigest'.  The original+-- file will be left on disk.+storeFile :: (MonadBaseControl IO m, MonadError CsError m, MonadIO m, MonadResource m) =>+             ContentStore           -- ^ An opened 'ContentStore'.+          -> FilePath               -- ^ The file to be stored.+          -> m ObjectDigest+storeFile cs fp = do+    lbs <- liftIO $ LBS.readFile fp+    storeLazyByteString cs lbs
+ Data/ContentStore/Config.hs view
@@ -0,0 +1,81 @@+{-# LANGUAGE OverloadedStrings #-}+{-# LANGUAGE RecordWildCards #-}++-- | Module: Data.ContentStore.Config+-- Copyright: (c) 2017 Red Hat, Inc.+-- License: LGPL+--+-- Maintainer: https://github.com/weldr+-- Stability: alpha+-- Portability: portable+--+-- Manage the content store's internal config file.++module Data.ContentStore.Config(Config(..),+                                defaultConfig,+                                readConfig,+                                writeConfig)+ where++-- Objects in the store are given file names that are their hash.+-- Lots of hash algorithms are available, which means we need to+-- know which one was used in a given store if we ever want to be+-- able to pull objects back out of it.  Thus, a config file.+--+-- Right now the only thing it's storing is the name of the hash+-- algorithm.  This may make using aeson seem like overkill, but+-- most of the config file parsing modules are unpleasant to use+-- and if this config file ever becomes too much more complicated,+-- we'll end up using aeson anyway.  Might as well start with it.++import           Data.Aeson+import           Data.Aeson.Types(Result(..), parseJSON)+import qualified Data.Text as T+import qualified Data.Text.IO as TIO+import           Text.Toml(parseTomlDoc)++{-# ANN module ("HLint: ignore Use newtype instead of data" :: String) #-}++-- | Configuration information needed by the content store.+data Config = Config {+    -- | What 'DigestAlgorithm' is in use by this content store?  While we do support+    -- several different algorithms, only one can ever be in use by a single content+    -- store.  Note that the 'ContentStore' record also stores this piece of+    -- information.  The difference is that here, we are only storing the text+    -- representation as given in a config file.+    confHash :: T.Text+ }++instance FromJSON Config where+    parseJSON = withObject "Config" $ \v ->+        Config <$> v .:? "hash" .!= "BLAKE2b256"++instance ToJSON Config where+    toJSON Config{..} = object [ "hash" .= toJSON confHash ]++-- | Construct a default 'Config' record useful for when creating a new 'ContentStore',+-- as with 'mkContentStore'.  Among other things, this is where the default hash+-- algorithm is defined.+defaultConfig :: Config+defaultConfig =+    Config { confHash = "BLAKE2b256" }++-- | Read a config file on disk, returning the 'Config' record on success and an error+-- message on error.  This function is typically not useful outside of content store+-- internals.+readConfig :: FilePath -> IO (Either T.Text Config)+readConfig path = do+    contents <- TIO.readFile path+    case parseTomlDoc "" contents of+        Left err  -> return $ Left $ T.pack $ show err+        Right tbl -> do let j = toJSON tbl+                        case (fromJSON j :: Result Config) of+                            Error err -> return $ Left $ T.pack $ show err+                            Success c -> return $ Right c++-- | Write a 'Config' object to disk.  This function is typically not useful outside+-- of content store internals.+writeConfig :: FilePath -> Config -> IO ()+writeConfig path Config{..} = TIO.writeFile path configText+ where+    configText = T.concat ["hash = \"", confHash, "\"\n"]
+ Data/ContentStore/Digest.hs view
@@ -0,0 +1,130 @@+{-# LANGUAGE OverloadedStrings #-}+{-# LANGUAGE GeneralizedNewtypeDeriving #-}+{-# LANGUAGE ExistentialQuantification #-}++-- |+-- Module: Data.ContentStore.Digest+-- Copyright: (c) 2017 Red Hat, Inc.+-- License: LGPL+--+-- Maintainer: https://github.com/weldr+-- Stability: alpha+-- Portability: portable+--+-- Functions for working with digest algorithms as used by the content store++module Data.ContentStore.Digest(DigestAlgorithm,+                                getDigestAlgorithm,+                                digestName,+                                digestSize,+                                digestInit,+                                DigestContext,+                                digestUpdate,+                                digestUpdates,+                                digestFinalize,+                                digestByteString,+                                digestLazyByteString,+                                ObjectDigest,+                                toHex,+                                fromByteString)+ where++import           Crypto.Hash+import           Data.ByteArray(Bytes, ByteArrayAccess, convert)+import           Data.ByteArray.Encoding(Base(..), convertToBase)+import qualified Data.ByteString as BS+import qualified Data.ByteString.Lazy as LBS+import qualified Data.Text as T+import           Data.Text.Encoding(decodeUtf8)++-- cryptonite is about 50% too clever with its types, if you ask me.+-- Here's simpler ones that we can use in ContentStore.++--+-- DIGEST TYPES+--++-- | A DigestAlgorithm represents one specific hash algorithm.+data DigestAlgorithm = forall a. (HashAlgorithm a, Show a) => DigestAlgorithm a++-- | Holds the context for a given instance of a 'DigestAlgorithm'.+data DigestContext = forall a. HashAlgorithm a => DigestContext (Context a)++-- | ObjectDigest is the (binary) representation of a digest.+newtype ObjectDigest = ObjectDigest Bytes+    deriving (Eq, Ord, ByteArrayAccess)++instance Show ObjectDigest where+    show (ObjectDigest b) = show b++--+-- PRIVATE FUNCTIONS+--++fromDigest :: HashAlgorithm a => Digest a -> ObjectDigest+fromDigest = ObjectDigest . convert++hashLazyWith :: HashAlgorithm a => a -> LBS.ByteString -> Digest a+hashLazyWith _ = hashlazy++--+-- PUBLIC FUNCTIONS+--++-- | Get the name of this 'DigestAlgorithm'.+digestName :: DigestAlgorithm -> String+digestName (DigestAlgorithm a) = show a++-- | The size of the 'ObjectDigest' returned by this 'DigestAlgorithm'.+digestSize :: DigestAlgorithm -> Int+digestSize (DigestAlgorithm a) = hashDigestSize a++-- | Initialize a new 'DigestContext' for this 'DigestAlgorithm'.+digestInit :: DigestAlgorithm -> DigestContext+digestInit (DigestAlgorithm a) = DigestContext $ hashInitWith a++-- | Update the 'DigestContext' with one 'ByteString'/'Bytes'/etc item.+digestUpdate :: ByteArrayAccess ba => DigestContext -> ba -> DigestContext+digestUpdate (DigestContext ctx) = DigestContext . hashUpdate ctx++-- | Update the 'DigestContext' with many 'ByteString'/'Bytes'/etc. items.+digestUpdates :: ByteArrayAccess ba => DigestContext -> [ba] -> DigestContext+digestUpdates (DigestContext ctx) = DigestContext . hashUpdates ctx++-- | Finish the digest, returning an 'ObjectDigest'.+digestFinalize :: DigestContext -> ObjectDigest+digestFinalize (DigestContext ctx) = fromDigest $ hashFinalize ctx++-- | Hash a strict 'ByteString' into an 'ObjectDigest'.+digestByteString :: DigestAlgorithm -> BS.ByteString -> ObjectDigest+digestByteString (DigestAlgorithm a) = fromDigest . hashWith a++-- | Hash a lazy 'Data.ByteString.Lazy.ByteString' into an 'ObjectDigest'.+digestLazyByteString :: DigestAlgorithm -> LBS.ByteString -> ObjectDigest+digestLazyByteString (DigestAlgorithm a) = fromDigest . hashLazyWith a++-- | Check and convert a 'ByteString' into an 'ObjectDigest'.+fromByteString :: ByteArrayAccess ba => DigestAlgorithm -> ba -> Maybe ObjectDigest+fromByteString (DigestAlgorithm a) = fmap fromDigest . digestFromByteStringWith a+-- helper for above+digestFromByteStringWith :: (HashAlgorithm a, ByteArrayAccess ba) => a -> ba -> Maybe (Digest a)+digestFromByteStringWith _ = digestFromByteString++-- | Convert an 'ObjectDigest' to its hex representation.+-- TODO: probably more efficient if we can just coerce the converted Bytes..+toHex :: ObjectDigest -> String+toHex = T.unpack . decodeUtf8 . convertToBase Base16+++-- | Given the 'Text' name of a digest algorithm, return a 'DigestAlgorithm'+-- (or Nothing if we don't recognize the DigestAlgorithm's name).+getDigestAlgorithm :: T.Text -> Maybe DigestAlgorithm+getDigestAlgorithm "SHA256"     = Just $ DigestAlgorithm SHA256+getDigestAlgorithm "SHA512"     = Just $ DigestAlgorithm SHA512+getDigestAlgorithm "BLAKE2"     = Just $ DigestAlgorithm Blake2b_512+getDigestAlgorithm "BLAKE2b"    = Just $ DigestAlgorithm Blake2b_512+getDigestAlgorithm "BLAKE2b512" = Just $ DigestAlgorithm Blake2b_512+getDigestAlgorithm "BLAKE2b256" = Just $ DigestAlgorithm Blake2b_256+getDigestAlgorithm "BLAKE2s"    = Just $ DigestAlgorithm Blake2s_256+getDigestAlgorithm "BLAKE2s256" = Just $ DigestAlgorithm Blake2s_256+getDigestAlgorithm _            = Nothing
+ LICENSE view
@@ -0,0 +1,502 @@+                  GNU LESSER GENERAL PUBLIC LICENSE+                       Version 2.1, February 1999++ Copyright (C) 1991, 1999 Free Software Foundation, Inc.+ 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA+ Everyone is permitted to copy and distribute verbatim copies+ of this license document, but changing it is not allowed.++[This is the first released version of the Lesser GPL.  It also counts+ as the successor of the GNU Library Public License, version 2, hence+ the version number 2.1.]++                            Preamble++  The licenses for most software are designed to take away your+freedom to share and change it.  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+ Setup.hs view
@@ -0,0 +1,2 @@+import Distribution.Simple+main = defaultMain
+ content-store.cabal view
@@ -0,0 +1,66 @@+name:                content-store+version:             0.1.0+synopsis:            Store and retrieve data from an on-disk store+description:         This module provides a way to store and retrieve arbitrary+                     data from an on-disk store, similar to how a source+                     control system works but without the assumptions of such+                     a system.+homepage:            https://github.com/weldr/content-store+category:            System+author:              Chris Lumens+maintainer:          clumens@redhat.com+license:             LGPL+license-file:        LICENSE+build-type:          Simple+cabal-version:       >= 1.10++extra-source-files:  ChangeLog.md,+                     tests/*.hs,+                     tests/Data/*.hs,+                     tests/Data/ContentStore/*.hs++source-repository   head+    type:           git+    location:       https://github.com/weldr/content-store++library+  exposed-modules:   Data.ContentStore,+                     Data.ContentStore.Config,+                     Data.ContentStore.Digest++  build-depends:     aeson >= 1.2.2.0 && < 1.3.0.0,+                     base >= 4.9 && < 5.0,+                     bytestring >= 0.10 && < 0.11,+                     cond >= 0.4.1.1 && < 0.5.0.0,+                     conduit >= 1.0.11 && < 1.3,+                     conduit-combinators >= 1.1.0 && < 1.2,+                     conduit-extra >= 1.1.0 && < 1.2,+                     cryptonite >= 0.22 && < 0.30,+                     directory >= 1.3.0.0 && < 1.4.0.0,+                     filepath >= 1.4.1.1 && < 1.5.0.0,+                     htoml >= 1.0.0.0 && < 1.1.0.0,+                     monad-control >= 1.0.2.2 && < 1.1.0.0,+                     memory >= 0.14.3 && < 0.15.0,+                     mtl >= 2.2.1 && < 2.3,+                     resourcet >= 1.1.9 && < 1.2,+                     temporary >= 1.2.1.1 && < 1.3.0.0,+                     text >= 1.2.2.2 && < 1.3,+                     transformers >= 0.5.2.0 && < 0.6.0.0,+                     transformers-base >= 0.4.4 && < 0.5.0,+                     unix >= 2.7.2.1 && < 2.8.0.0++  default-language:  Haskell2010+  ghc-options:       -Wall++test-suite spec+  type: exitcode-stdio-1.0+  main-is: Spec.hs+  hs-source-dirs: tests+  build-depends:    base == 4.*,+                    bytestring >= 0.10 && < 0.11,+                    hspec == 2.*,+                    memory >= 0.14.3 && < 0.15.0,+                    content-store++  default-language: Haskell2010+  ghc-options: -Wall
+ tests/Data/ContentStore/DigestSpec.hs view
@@ -0,0 +1,52 @@+{-# LANGUAGE OverloadedStrings #-}++module Data.ContentStore.DigestSpec(spec) where++import Test.Hspec+import Data.Maybe(fromJust)+import Data.ContentStore.Digest+import qualified Data.ByteString as B+import qualified Data.ByteArray as BA++testInput :: B.ByteString+testInput = "The Dude abides."++testSHA256Digest :: B.ByteString+testSHA256Digest = "\xcd\x9c\xf3\x08\x62\x61\x24\xa7\x81\x81\xc0\x22\xfb\x9d\x0d\x51\x1a\xf1\xc1\x5d\x32\x20\x12\xf0\xa6\x9d\xfe\x86\x40\xc3\x40\xaa"++testSHA256Hex :: String+testSHA256Hex = "cd9cf308626124a78181c022fb9d0d511af1c15d322012f0a69dfe8640c340aa"++spec :: Spec+spec = do+    describe "Digest.DigestAlgorithm" $ do+        it "knows about SHA256" $+            digestName <$> getDigestAlgorithm "SHA256" `shouldBe` Just "SHA256"++        let daSHA256 = fromJust $ getDigestAlgorithm "SHA256"+        it "has the correct size for SHA256" $+            digestSize daSHA256 `shouldBe` 32++        let od = digestByteString daSHA256 testInput+        let hex = toHex od++        it "does SHA256 correctly" $+            BA.convert od `shouldBe` testSHA256Digest++        it "converts ObjectDigest to hex" $+            hex `shouldBe` testSHA256Hex++    describe "Digest.DigestContext" $ do+        let da = fromJust $ getDigestAlgorithm "SHA256"+        let ctx = digestInit da+        it "can do digests piece by piece" $ do+            let hex = toHex $ digestFinalize $ digestUpdate ctx testInput+            hex `shouldBe` testSHA256Hex++    describe "fromByteString" $ do+        let da = fromJust $ getDigestAlgorithm "SHA256"+        let od = digestByteString da testInput+        it "accepts a 32-byte ByteString" $+            fromByteString da testSHA256Digest `shouldBe` Just od+        it "rejects wrong-sized ByteString" $+            fromByteString da (B.take 20 testSHA256Digest) `shouldBe` Nothing
+ tests/Data/ContentStoreSpec.hs view
@@ -0,0 +1,10 @@+module Data.ContentStoreSpec(spec) where++import Test.Hspec+import Data.ContentStore++spec :: Spec+spec =+    describe "ContentStore" $+        it "has dummy test" $+            () `shouldBe` ()
+ tests/Spec.hs view
@@ -0,0 +1,1 @@+{-# OPTIONS_GHC -F -pgmF hspec-discover #-}