Cabal/Distribution/Simple/BuildToolDepends.hs

   1 -- |
   2 --
   3 -- This modules provides functions for working with both the legacy
   4 -- "build-tools" field, and its replacement, "build-tool-depends". Prefer using
   5 -- the functions contained to access those fields directly.
   6 module Distribution.Simple.BuildToolDepends where
   7
   8 import           Data.Maybe
   9 import qualified Data.Map as Map
  10
  11 import           Distribution.Package
  12 import           Distribution.PackageDescription
  13 import           Distribution.Types.ExeDependency
  14 import           Distribution.Types.LegacyExeDependency
  15 import           Distribution.Types.UnqualComponentName
  16
  17 -- | Desugar a "build-tools" entry into proper a executable dependency if
  18 -- possible.
  19 --
  20 -- An entry can be so desguared in two cases:
  21 --
  22 -- 1. The name in build-tools matches a locally defined executable.  The
  23 --    executable dependency produced is on that exe in the current package.
  24 --
  25 -- 2. The name in build-tools matches a hard-coded set of known tools.  For now,
  26 --    the executable dependency produced is one an executable in a package of
  27 --    the same, but the hard-coding could just as well be per-key.
  28 --
  29 -- The first cases matches first.
  30 desugarBuildTool :: PackageDescription
  31                  -> LegacyExeDependency
  32                  -> Maybe ExeDependency
  33 desugarBuildTool pkg led =
  34   if foundLocal
  35   then Just $ ExeDependency (packageName pkg) toolName reqVer
  36   else Map.lookup name whiteMap
  37   where
  38     LegacyExeDependency name reqVer = led
  39     toolName = mkUnqualComponentName name
  40     foundLocal = toolName `elem` map exeName (executables pkg)
  41     whitelist = [ "hscolour", "haddock", "happy", "alex", "hsc2hs", "c2hs"
  42                 , "cpphs", "greencard"]
  43     whiteMap  = Map.fromList $ flip map whitelist $ \n ->
  44       (n, ExeDependency (mkPackageName n) (mkUnqualComponentName n) reqVer)
  45
  46 -- | Get everything from "build-tool-depends", along with entries from
  47 -- "build-tools" that we know how to desugar.
  48 --
  49 -- This should almost always be used instead of just accessing the
  50 -- `toolDepends` field directly.
  51 getAllToolDependencies :: PackageDescription
  52                        -> BuildInfo
  53                        -> [ExeDependency]
  54 getAllToolDependencies pkg bi =
  55   toolDepends bi ++ mapMaybe (desugarBuildTool pkg) (buildTools bi)
  56
  57 -- | Does the given executable dependency map to this current package?
  58 --
  59 -- This is a tiny function, but used in a number of places.
  60 --
  61 -- This function is only sound to call on `BuildInfo`s from the given package
  62 -- description. This is because it just filters the package names of each
  63 -- dependency, and does not check whether version bounds in fact exclude the
  64 -- current package, or the referenced components in fact exist in the current
  65 -- package.
  66 --
  67 -- This is OK because when a package is loaded, it is checked (in
  68 -- `Distribution.Package.Check`) that dependencies matching internal components
  69 -- do indeed have version bounds accepting the current package, and any
  70 -- depended-on component in the current package actually exists. In fact this
  71 -- check is performed by gathering the internal tool dependencies of each
  72 -- component of the package according to this module, and ensuring those
  73 -- properties on each so-gathered dependency.
  74 --
  75 -- version bounds and components of the package are unchecked. This is because
  76 -- we sanitize exe deps so that the matching name implies these other
  77 -- conditions.
  78 isInternal :: PackageDescription -> ExeDependency -> Bool
  79 isInternal pkg (ExeDependency n _ _) = n == packageName pkg
  80
  81
  82 -- | Get internal "build-tool-depends", along with internal "build-tools"
  83 --
  84 -- This is a tiny function, but used in a number of places. The same
  85 -- restrictions that apply to `isInternal` also apply to this function.
  86 getAllInternalToolDependencies :: PackageDescription
  87                                -> BuildInfo
  88                                -> [ExeDependency]
  89 getAllInternalToolDependencies pkg bi =
  90   filter (isInternal pkg) $ getAllToolDependencies pkg bi