{-# LANGUAGE CPP #-}
{-# LANGUAGE DeriveDataTypeable #-}
{-# LANGUAGE NamedFieldPuns #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE RecordWildCards #-}
{-# OPTIONS_GHC -Wall #-}
module Dhall.Import (
exprFromImport
, load
, loadWith
, hashExpression
, hashExpressionToCode
, Status
, emptyStatus
, stack
, cache
, manager
, protocolVersion
, normalizer
, startingContext
, resolver
, Cycle(..)
, ReferentiallyOpaque(..)
, Imported(..)
, PrettyHttpException(..)
, MissingFile(..)
, MissingEnvironmentVariable(..)
, MissingImports(..)
) where
import Control.Applicative (Alternative(..))
import Codec.CBOR.Term (Term)
import Control.Applicative (empty)
import Control.Exception (Exception, SomeException, throwIO, toException)
import Control.Monad (guard)
import Control.Monad.Catch (throwM, MonadCatch(catch), catches, Handler(..))
import Control.Monad.IO.Class (MonadIO(..))
import Control.Monad.Trans.State.Strict (StateT)
import Crypto.Hash (SHA256)
import Data.CaseInsensitive (CI)
import Data.List.NonEmpty (NonEmpty(..))
import Data.Semigroup (sconcat, (<>))
import Data.Text (Text)
#if MIN_VERSION_base(4,8,0)
#else
import Data.Traversable (traverse)
#endif
import Data.Typeable (Typeable)
import System.FilePath ((</>))
import Dhall.Binary (ProtocolVersion(..))
import Dhall.Core
( Expr(..)
, Chunks(..)
, Directory(..)
, File(..)
, FilePrefix(..)
, ImportHashed(..)
, ImportType(..)
, ImportMode(..)
, Import(..)
, ReifiedNormalizer(..)
, Scheme(..)
, URL(..)
)
#ifdef MIN_VERSION_http_client
import Dhall.Import.HTTP
#endif
import Dhall.Import.Types
import Dhall.Parser (Parser(..), ParseError(..), Src(..))
import Dhall.TypeCheck (X(..))
import Lens.Family.State.Strict (zoom)
import qualified Codec.Serialise
import qualified Control.Monad.Trans.Maybe as Maybe
import qualified Control.Monad.Trans.State.Strict as State
import qualified Crypto.Hash
import qualified Data.ByteString
import qualified Data.ByteString.Lazy
import qualified Data.CaseInsensitive
import qualified Data.Foldable
import qualified Data.HashMap.Strict.InsOrd
import qualified Data.List.NonEmpty as NonEmpty
import qualified Data.Map.Strict as Map
import qualified Data.Text.Encoding
import qualified Data.Text as Text
import qualified Data.Text.IO
import qualified Dhall.Binary
import qualified Dhall.Core
import qualified Dhall.Parser
import qualified Dhall.Pretty.Internal
import qualified Dhall.TypeCheck
import qualified System.Environment
import qualified System.Directory as Directory
import qualified System.FilePath as FilePath
import qualified Text.Megaparsec
import qualified Text.Parser.Combinators
import qualified Text.Parser.Token
newtype Cycle = Cycle
{ cyclicImport :: Import
}
deriving (Typeable)
instance Exception Cycle
instance Show Cycle where
show (Cycle import_) =
"\nCyclic import: " ++ Dhall.Pretty.Internal.prettyToString import_
newtype ReferentiallyOpaque = ReferentiallyOpaque
{ opaqueImport :: Import
} deriving (Typeable)
instance Exception ReferentiallyOpaque
instance Show ReferentiallyOpaque where
show (ReferentiallyOpaque import_) =
"\nReferentially opaque import: " ++ Dhall.Pretty.Internal.prettyToString import_
data Imported e = Imported
{ importStack :: NonEmpty Import
, nested :: e
} deriving (Typeable)
instance Exception e => Exception (Imported e)
instance Show e => Show (Imported e) where
show (Imported imports e) =
concat (zipWith indent [0..] toDisplay)
++ show e
where
indent n import_ =
"\n" ++ replicate (2 * n) ' ' ++ "↳ " ++ Dhall.Pretty.Internal.prettyToString import_
canonical = NonEmpty.toList (canonicalizeAll imports)
toDisplay = drop 1 (reverse canonical)
data MissingFile = MissingFile FilePath
deriving (Typeable)
instance Exception MissingFile
instance Show MissingFile where
show (MissingFile path) =
"\n"
<> "\ESC[1;31mError\ESC[0m: Missing file "
<> path
<> "\n"
newtype MissingEnvironmentVariable = MissingEnvironmentVariable { name :: Text }
deriving (Typeable)
instance Exception MissingEnvironmentVariable
instance Show MissingEnvironmentVariable where
show (MissingEnvironmentVariable {..}) =
"\n"
<> "\ESC[1;31mError\ESC[0m: Missing environment variable\n"
<> "\n"
<> "↳ " <> Text.unpack name
newtype MissingImports = MissingImports [SomeException]
instance Exception MissingImports
instance Show MissingImports where
show (MissingImports []) =
"\n"
<> "\ESC[1;31mError\ESC[0m: No valid imports"
<> "\n"
show (MissingImports [e]) = show e
show (MissingImports es) =
"\n"
<> "\ESC[1;31mError\ESC[0m: Failed to resolve imports. Error list:"
<> "\n"
<> concatMap (\e -> "\n" <> show e <> "\n") es
<> "\n"
throwMissingImport :: (MonadCatch m, Exception e) => e -> m a
throwMissingImport e = throwM (MissingImports [(toException e)])
data CannotImportHTTPURL =
CannotImportHTTPURL
String
(Maybe [(CI Data.ByteString.ByteString, Data.ByteString.ByteString)])
deriving (Typeable)
instance Exception CannotImportHTTPURL
instance Show CannotImportHTTPURL where
show (CannotImportHTTPURL url _mheaders) =
"\n"
<> "\ESC[1;31mError\ESC[0m: Cannot import HTTP URL.\n"
<> "\n"
<> "Dhall was compiled without the 'with-http' flag.\n"
<> "\n"
<> "The requested URL was: "
<> url
<> "\n"
canonicalizeAll :: NonEmpty Import -> NonEmpty Import
canonicalizeAll = NonEmpty.scanr1 step
where
step a parent = canonicalizeImport (a :| [parent])
class Canonicalize path where
canonicalize :: path -> path
instance Canonicalize Directory where
canonicalize (Directory []) = Directory []
canonicalize (Directory ("." : components₀)) =
canonicalize (Directory components₀)
canonicalize (Directory (".." : components₀)) =
case canonicalize (Directory components₀) of
Directory [] ->
Directory [ ".." ]
Directory (".." : components₁) ->
Directory (".." : ".." : components₁)
Directory (_ : components₁) ->
Directory components₁
canonicalize (Directory (component : components₀)) =
Directory (component : components₁)
where
Directory components₁ = canonicalize (Directory components₀)
instance Canonicalize File where
canonicalize (File { directory, .. }) =
File { directory = canonicalize directory, .. }
instance Canonicalize ImportType where
canonicalize (Local prefix file) =
Local prefix (canonicalize file)
canonicalize (Remote (URL {..})) =
Remote (URL { path = canonicalize path, ..})
canonicalize (Env name) =
Env name
canonicalize Missing =
Missing
instance Canonicalize ImportHashed where
canonicalize (ImportHashed hash importType) =
ImportHashed hash (canonicalize importType)
instance Canonicalize Import where
canonicalize (Import importHashed importMode) =
Import (canonicalize importHashed) importMode
canonicalizeImport :: NonEmpty Import -> Import
canonicalizeImport imports =
canonicalize (sconcat (NonEmpty.reverse imports))
toHeaders
:: Expr s a
-> Maybe [(CI Data.ByteString.ByteString, Data.ByteString.ByteString)]
toHeaders (ListLit _ hs) = do
hs' <- mapM toHeader hs
return (Data.Foldable.toList hs')
toHeaders _ = do
empty
toHeader
:: Expr s a
-> Maybe (CI Data.ByteString.ByteString, Data.ByteString.ByteString)
toHeader (RecordLit m) = do
TextLit (Chunks [] keyText ) <- Data.HashMap.Strict.InsOrd.lookup "header" m
TextLit (Chunks [] valueText) <- Data.HashMap.Strict.InsOrd.lookup "value" m
let keyBytes = Data.Text.Encoding.encodeUtf8 keyText
let valueBytes = Data.Text.Encoding.encodeUtf8 valueText
return (Data.CaseInsensitive.mk keyBytes, valueBytes)
toHeader _ = do
empty
data HashMismatch = HashMismatch
{ expectedHash :: Crypto.Hash.Digest SHA256
, actualHash :: Crypto.Hash.Digest SHA256
} deriving (Typeable)
instance Exception HashMismatch
instance Show HashMismatch where
show (HashMismatch {..}) =
"\n"
<> "\ESC[1;31mError\ESC[0m: Import integrity check failed\n"
<> "\n"
<> "Expected hash:\n"
<> "\n"
<> "↳ " <> show expectedHash <> "\n"
<> "\n"
<> "Actual hash:\n"
<> "\n"
<> "↳ " <> show actualHash <> "\n"
exprFromImport :: Import -> StateT (Status IO) IO (Expr Src Import)
exprFromImport import_@(Import {..}) = do
let ImportHashed {..} = importHashed
case hash of
Nothing -> do
exprFromUncachedImport import_
Just expectedHash -> do
Status {..} <- State.get
result <- Maybe.runMaybeT (getCacheFile expectedHash)
case result of
Just (Read, cacheFile) -> do
bytesStrict <- liftIO (Data.ByteString.readFile cacheFile)
let actualHash = Crypto.Hash.hash bytesStrict
if expectedHash == actualHash
then return ()
else liftIO (Control.Exception.throwIO (HashMismatch {..}))
let bytesLazy = Data.ByteString.Lazy.fromStrict bytesStrict
term <- case Codec.Serialise.deserialiseOrFail bytesLazy of
Left exception ->
liftIO (Control.Exception.throwIO exception)
Right term ->
return term
case Dhall.Binary.decode term of
Left exception ->
liftIO (Control.Exception.throwIO exception)
Right expression ->
return expression
Just (Write, cacheFile) -> do
expression <- exprFromUncachedImport import_
let _stack' = NonEmpty.cons import_ _stack
zoom stack (State.put _stack')
resolvedExpression <- loadWith expression
zoom stack (State.put _stack)
case Dhall.TypeCheck.typeWith _startingContext resolvedExpression of
Left _ -> do
return ()
Right _ -> do
let normalizedExpression =
Dhall.Core.alphaNormalize
(Dhall.Core.normalizeWith
(getReifiedNormalizer _normalizer)
resolvedExpression
)
let bytes =
encodeExpression _protocolVersion normalizedExpression
let actualHash = Crypto.Hash.hash bytes
if expectedHash == actualHash
then return ()
else liftIO (Control.Exception.throwIO (HashMismatch {..}))
liftIO (Data.ByteString.writeFile cacheFile bytes)
return expression
Nothing -> do
exprFromUncachedImport import_
data CacheMode = Read | Write
getCacheFile
:: (Alternative m, MonadIO m)
=> Crypto.Hash.Digest SHA256 -> m (CacheMode, FilePath)
getCacheFile hash = do
let assertDirectory directory = do
let private = transform Directory.emptyPermissions
where
transform =
Directory.setOwnerReadable True
. Directory.setOwnerWritable True
. Directory.setOwnerSearchable True
let accessible path =
Directory.readable path
&& Directory.writable path
&& Directory.searchable path
directoryExists <- liftIO (Directory.doesDirectoryExist directory)
if directoryExists
then do
permissions <- liftIO (Directory.getPermissions directory)
guard (accessible permissions)
else do
assertDirectory (FilePath.takeDirectory directory)
liftIO (Directory.createDirectory directory)
liftIO (Directory.setPermissions directory private)
cacheDirectory <- liftIO $ Directory.getXdgDirectory Directory.XdgCache ""
assertDirectory cacheDirectory
let dhallDirectory = cacheDirectory </> "dhall"
assertDirectory dhallDirectory
let cacheFile = dhallDirectory </> show hash
cacheFileExists <- liftIO (Directory.doesPathExist cacheFile)
if cacheFileExists
then do
True <- liftIO (Directory.doesFileExist cacheFile)
return (Read, cacheFile)
else do
return (Write, cacheFile)
exprFromUncachedImport :: Import -> StateT (Status IO) IO (Expr Src Import)
exprFromUncachedImport (Import {..}) = do
let ImportHashed {..} = importHashed
(path, text) <- case importType of
Local prefix (File {..}) -> liftIO $ do
let Directory {..} = directory
prefixPath <- case prefix of
Home -> do
Directory.getHomeDirectory
Absolute -> do
return "/"
Here -> do
Directory.getCurrentDirectory
let cs = map Text.unpack (file : components)
let cons component dir = dir </> component
let path = foldr cons prefixPath cs
exists <- Directory.doesFileExist path
if exists
then return ()
else throwMissingImport (MissingFile path)
text <- Data.Text.IO.readFile path
return (path, text)
Remote (URL scheme authority file query fragment maybeHeaders) -> do
let prefix =
(case scheme of HTTP -> "http"; HTTPS -> "https")
<> "://"
<> authority
let fileText = Dhall.Pretty.Internal.prettyToStrictText file
let suffix =
(case query of Nothing -> ""; Just q -> "?" <> q)
<> (case fragment of Nothing -> ""; Just f -> "#" <> f)
let url = Text.unpack (prefix <> fileText <> suffix)
mheaders <- case maybeHeaders of
Nothing -> return Nothing
Just importHashed_ -> do
expr <- loadWith (Embed (Import importHashed_ Code))
let expected :: Expr Src X
expected =
App List
( Record
( Data.HashMap.Strict.InsOrd.fromList
[("header", Text), ("value", Text)]
)
)
let suffix_ = Dhall.Pretty.Internal.prettyToStrictText expected
let annot = case expr of
Note (Src begin end bytes) _ ->
Note (Src begin end bytes') (Annot expr expected)
where
bytes' = bytes <> " : " <> suffix_
_ ->
Annot expr expected
case Dhall.TypeCheck.typeOf annot of
Left err -> liftIO (throwIO err)
Right _ -> return ()
let expr' = Dhall.Core.normalize expr
case toHeaders expr' of
Just headers -> do
return (Just headers)
Nothing -> do
liftIO (throwIO InternalError)
#ifdef MIN_VERSION_http_client
fetchFromHttpUrl url mheaders
#else
liftIO (throwIO (CannotImportHTTPURL url mheaders))
#endif
Env env -> liftIO $ do
x <- System.Environment.lookupEnv (Text.unpack env)
case x of
Just string -> return (Text.unpack env, Text.pack string)
Nothing -> throwMissingImport (MissingEnvironmentVariable env)
Missing -> liftIO $ do
throwM (MissingImports [])
case importMode of
Code -> do
let parser = unParser $ do
Text.Parser.Token.whiteSpace
r <- Dhall.Parser.expr
Text.Parser.Combinators.eof
return r
case Text.Megaparsec.parse parser path text of
Left errInfo -> do
liftIO (throwIO (ParseError errInfo text))
Right expr -> do
return expr
RawText -> do
return (TextLit (Chunks [] text))
emptyStatus :: FilePath -> Status IO
emptyStatus = emptyStatusWith exprFromImport
loadWith :: MonadCatch m => Expr Src Import -> StateT (Status m) m (Expr Src X)
loadWith expr₀ = case expr₀ of
Embed import_ -> do
Status {..} <- State.get
let imports = _stack
let local (Import (ImportHashed _ (Remote {})) _) = False
local (Import (ImportHashed _ (Local {})) _) = True
local (Import (ImportHashed _ (Env {})) _) = True
local (Import (ImportHashed _ (Missing {})) _) = True
let parent = canonicalizeImport imports
let imports' = NonEmpty.cons import_ imports
let here = canonicalizeImport imports'
if local here && not (local parent)
then throwMissingImport (Imported imports (ReferentiallyOpaque import_))
else return ()
expr <- if here `elem` canonicalizeAll imports
then throwMissingImport (Imported imports (Cycle import_))
else do
case Map.lookup here _cache of
Just expr -> return expr
Nothing -> do
let handler₀
:: (MonadCatch m)
=> MissingImports
-> StateT (Status m) m (Expr Src Import)
handler₀ e@(MissingImports []) = throwM e
handler₀ (MissingImports [e]) =
throwMissingImport (Imported imports' e)
handler₀ (MissingImports es) = throwM
(MissingImports
(fmap
(\e -> (toException (Imported imports' e)))
es))
handler₁
:: (MonadCatch m)
=> SomeException
-> StateT (Status m) m (Expr Src Import)
handler₁ e =
throwMissingImport (Imported imports' e)
let loadDynamic = _resolver here
expr' <- loadDynamic `catches` [ Handler handler₀, Handler handler₁ ]
zoom stack (State.put imports')
expr'' <- loadWith expr'
zoom stack (State.put imports)
expr''' <- case Dhall.TypeCheck.typeWith _startingContext expr'' of
Left err -> throwM (Imported imports' err)
Right _ -> return (Dhall.Core.normalizeWith (getReifiedNormalizer _normalizer) expr'')
zoom cache (State.put $! Map.insert here expr''' _cache)
return expr'''
case hash (importHashed import_) of
Nothing -> do
return ()
Just expectedHash -> do
let actualHash =
hashExpression _protocolVersion (Dhall.Core.alphaNormalize expr)
if expectedHash == actualHash
then return ()
else throwMissingImport (Imported imports' (HashMismatch {..}))
return expr
ImportAlt a b -> loadWith a `catch` handler₀
where
handler₀ (MissingImports es₀) =
loadWith b `catch` handler₁
where
handler₁ (MissingImports es₁) =
throwM (MissingImports (es₀ ++ es₁))
Const a -> pure (Const a)
Var a -> pure (Var a)
Lam a b c -> Lam <$> pure a <*> loadWith b <*> loadWith c
Pi a b c -> Pi <$> pure a <*> loadWith b <*> loadWith c
App a b -> App <$> loadWith a <*> loadWith b
Let a b c d -> Let <$> pure a <*> mapM loadWith b <*> loadWith c <*> loadWith d
Annot a b -> Annot <$> loadWith a <*> loadWith b
Bool -> pure Bool
BoolLit a -> pure (BoolLit a)
BoolAnd a b -> BoolAnd <$> loadWith a <*> loadWith b
BoolOr a b -> BoolOr <$> loadWith a <*> loadWith b
BoolEQ a b -> BoolEQ <$> loadWith a <*> loadWith b
BoolNE a b -> BoolNE <$> loadWith a <*> loadWith b
BoolIf a b c -> BoolIf <$> loadWith a <*> loadWith b <*> loadWith c
Natural -> pure Natural
NaturalLit a -> pure (NaturalLit a)
NaturalFold -> pure NaturalFold
NaturalBuild -> pure NaturalBuild
NaturalIsZero -> pure NaturalIsZero
NaturalEven -> pure NaturalEven
NaturalOdd -> pure NaturalOdd
NaturalToInteger -> pure NaturalToInteger
NaturalShow -> pure NaturalShow
NaturalPlus a b -> NaturalPlus <$> loadWith a <*> loadWith b
NaturalTimes a b -> NaturalTimes <$> loadWith a <*> loadWith b
Integer -> pure Integer
IntegerLit a -> pure (IntegerLit a)
IntegerShow -> pure IntegerShow
IntegerToDouble -> pure IntegerToDouble
Double -> pure Double
DoubleLit a -> pure (DoubleLit a)
DoubleShow -> pure DoubleShow
Text -> pure Text
TextLit (Chunks a b) -> fmap TextLit (Chunks <$> mapM (mapM loadWith) a <*> pure b)
TextAppend a b -> TextAppend <$> loadWith a <*> loadWith b
List -> pure List
ListLit a b -> ListLit <$> mapM loadWith a <*> mapM loadWith b
ListAppend a b -> ListAppend <$> loadWith a <*> loadWith b
ListBuild -> pure ListBuild
ListFold -> pure ListFold
ListLength -> pure ListLength
ListHead -> pure ListHead
ListLast -> pure ListLast
ListIndexed -> pure ListIndexed
ListReverse -> pure ListReverse
Optional -> pure Optional
OptionalLit a b -> OptionalLit <$> loadWith a <*> mapM loadWith b
OptionalFold -> pure OptionalFold
OptionalBuild -> pure OptionalBuild
Record a -> Record <$> mapM loadWith a
RecordLit a -> RecordLit <$> mapM loadWith a
Union a -> Union <$> mapM loadWith a
UnionLit a b c -> UnionLit <$> pure a <*> loadWith b <*> mapM loadWith c
Combine a b -> Combine <$> loadWith a <*> loadWith b
CombineTypes a b -> CombineTypes <$> loadWith a <*> loadWith b
Prefer a b -> Prefer <$> loadWith a <*> loadWith b
Merge a b c -> Merge <$> loadWith a <*> loadWith b <*> mapM loadWith c
Constructors a -> Constructors <$> loadWith a
Field a b -> Field <$> loadWith a <*> pure b
Project a b -> Project <$> loadWith a <*> pure b
Note a b -> Note <$> pure a <*> loadWith b
load :: Expr Src Import -> IO (Expr Src X)
load expression = State.evalStateT (loadWith expression) (emptyStatus ".")
encodeExpression
:: forall s . ProtocolVersion -> Expr s X -> Data.ByteString.ByteString
encodeExpression _protocolVersion expression = bytesStrict
where
intermediateExpression :: Expr s Import
intermediateExpression = fmap absurd expression
term :: Term
term = Dhall.Binary.encode _protocolVersion intermediateExpression
bytesLazy = Codec.Serialise.serialise term
bytesStrict = Data.ByteString.Lazy.toStrict bytesLazy
hashExpression :: ProtocolVersion -> Expr s X -> (Crypto.Hash.Digest SHA256)
hashExpression _protocolVersion expression =
Crypto.Hash.hash (encodeExpression _protocolVersion expression)
hashExpressionToCode :: ProtocolVersion -> Expr s X -> Text
hashExpressionToCode _protocolVersion expr =
"sha256:" <> Text.pack (show (hashExpression _protocolVersion expr))