Cabal/Distribution/Types/AbiDependency.hs

   1 {-# LANGUAGE DeriveGeneric #-}
   2 module Distribution.Types.AbiDependency where
   3
   4 import Distribution.Compat.Prelude
   5 import Prelude ()
   6
   7 import Distribution.Parsec.Class
   8 import Distribution.Pretty
   9 import Distribution.Text
  10
  11 import qualified Distribution.Compat.CharParsing as P
  12 import qualified Distribution.Compat.ReadP       as Parse
  13 import qualified Distribution.Package            as Package
  14 import qualified Text.PrettyPrint                as Disp
  15
  16 -- | An ABI dependency is a dependency on a library which also
  17 -- records the ABI hash ('abiHash') of the library it depends
  18 -- on.
  19 --
  20 -- The primary utility of this is to enable an extra sanity when
  21 -- GHC loads libraries: it can check if the dependency has a matching
  22 -- ABI and if not, refuse to load this library.  This information
  23 -- is critical if we are shadowing libraries; differences in the
  24 -- ABI hash let us know what packages get shadowed by the new version
  25 -- of a package.
  26 data AbiDependency = AbiDependency {
  27         depUnitId  :: Package.UnitId,
  28         depAbiHash :: Package.AbiHash
  29     }
  30   deriving (Eq, Generic, Read, Show)
  31
  32 instance Pretty AbiDependency where
  33     pretty (AbiDependency uid abi) =
  34         disp uid <<>> Disp.char '=' <<>> disp abi
  35
  36 instance  Parsec AbiDependency where
  37     parsec = do
  38         uid <- parsec
  39         _ <- P.char '='
  40         abi <- parsec
  41         return (AbiDependency uid abi)
  42
  43 instance Text AbiDependency where
  44     parse = do
  45         uid <- parse
  46         _ <- Parse.char '='
  47         abi <- parse
  48         return (AbiDependency uid abi)
  49
  50 instance Binary AbiDependency
  51
  52 instance NFData AbiDependency where rnf = genericRnf