diff --git a/CHANGELOG.md b/CHANGELOG.md new file mode 100644 --- /dev/null +++ b/CHANGELOG.md @@ -0,0 +1,5 @@ +# Revision history for cabal-pkg-config-version-hook + +## 0.1.0.0 -- 2022-03-07 + +* First version. Main feature is room for improvement. diff --git a/README.md b/README.md new file mode 100644 --- /dev/null +++ b/README.md @@ -0,0 +1,4 @@ + +# A Cabal setup hook for pkg-config version info + +Cabal doesn't natively give access to version information from `pkg-config` (yet?). This setup hook gets the version and makes it available via Haskell CPP and C/C++ macros, as well as setting Cabal flags automatically. diff --git a/cabal-pkg-config-version-hook.cabal b/cabal-pkg-config-version-hook.cabal new file mode 100644 --- /dev/null +++ b/cabal-pkg-config-version-hook.cabal @@ -0,0 +1,27 @@ +cabal-version: 2.4 +name: cabal-pkg-config-version-hook +version: 0.1.0.0 +synopsis: Make Cabal aware of pkg-config package versions +description: A setup hook for Cabal that determines the compile-time version of a pkg-config package and adds CPP macros and enables flags. +-- A URL where users can report bugs. +-- bug-reports: +homepage: https://github.com/hercules-ci/hercules-ci-agent/tree/master/cabal-pkg-config-version-hook#readme +license: BSD-3-Clause +author: Robert Hensing +maintainer: info@hercules-ci.com +copyright: cabal-pkg-config-version-hook contributors +category: Distribution +extra-source-files: + CHANGELOG.md + README.md + +library + exposed-modules: + Distribution.PkgConfigVersionHook + build-depends: + base ==4.* + , Cabal >= 2.2.0.0 + , process + , lens + hs-source-dirs: src + default-language: Haskell2010 diff --git a/src/Distribution/PkgConfigVersionHook.hs b/src/Distribution/PkgConfigVersionHook.hs new file mode 100644 --- /dev/null +++ b/src/Distribution/PkgConfigVersionHook.hs @@ -0,0 +1,164 @@ +-- | +-- +-- Example: +-- +-- @ +-- main :: IO () +-- main = +-- defaultMainWithHooks $ +-- simpleUserHooks +-- & addHook +-- (mkSettings "nix-store") +-- { macroName = "NIX", +-- flagPrefixName = "nix" +-- } +-- @ +-- +-- The above will look for a pkg-config package @nix-store@, and then +-- +-- * Define CPP, C and C++ macros +-- +-- * @NIX_MAJOR@, an integer +-- * @NIX_MINOR@, an integer +-- * @NIX_PATCH@, an integer; 0 if missing +-- * @NIX_IS_AT_LEAST(major,minor,patch)@, returning true when the discovered version @>=@ the specified version +-- +-- * Set or unset flags like `nix-2_4` so that the flag is true when the +-- discovered version is at least the version in the flag's name. +module Distribution.PkgConfigVersionHook + ( addHook, + mkSettings, + Settings (..), + composeConfHook, + ) +where + +import Control.Lens ((%~), (^.)) +import Control.Monad (when) +import qualified Data.Char as C +import Data.Foldable (toList) +import Data.Function ((&)) +import qualified Data.List as L +import Distribution.Simple +import Distribution.Simple.Setup (configConfigurationsFlags) +import Distribution.Types.BuildInfo.Lens (ccOptions, cppOptions, cxxOptions) +import Distribution.Types.Flag (flagName, mkFlagAssignment, mkFlagName, unFlagName) +import Distribution.Types.GenericPackageDescription.Lens + ( allCondTrees, + condBenchmarks, + condExecutables, + condForeignLibs, + condLibrary, + condSubLibraries, + condTestSuites, + genPackageFlags, + ) +import System.IO (hPutStrLn, stderr) +import System.Process (readProcess) +import qualified Text.ParserCombinators.ReadP as P +import Prelude hiding (log) + +-- | Hook into Cabal to provide pkg-config metadata. Can be applied multiple +-- times to support multiple packages. +addHook :: Settings -> UserHooks -> UserHooks +addHook settings hooks = hooks {confHook = composeConfHook settings (confHook hooks)} + +-- | How the metadata for a pkg-config package should be made available to the +-- cabal file. +data Settings = Settings + { -- | Name of the package; used for querying pkg-config. + pkgConfigName :: String, + -- | Name to use in the Haskell CPP and C/C++ preprocessor macros. + -- + -- For example, `pkgConfigName = "FOO"` will set the macros + -- + -- * @FOO_MAJOR@ + -- + -- * @FOO_MINOR@ + -- + -- * @FOO_PATCH@ + -- + -- * @FOO_IS_AT_LEAST(major, minor, patch)@ + macroName :: String, + -- | Name to use when setting flag values in the cabal file. + -- + -- Flags named with this prefix, followed by a dash, followed by a major version number, an underscore and a minor version number will be set when the detected package is at least that version. + flagPrefixName :: String + } + +-- | Derive a default 'Settings' value from just a pkg-config package name. +mkSettings :: String -> Settings +mkSettings name = + Settings + { pkgConfigName = name, + macroName = map (\x -> case x of '-' -> '_') name, + flagPrefixName = name + } + +-- | Extend the value of 'confHook'. It's what powers 'addHook'. +composeConfHook settings origHook = \(genericPackageDescription, hookedBuildInfo) confFlags -> do + (actualMajor, actualMinor, actualPatch) <- getPkgConfigPackageVersion (pkgConfigName settings) + + let defines = + [ "-D" <> macroName settings <> "_MAJOR=" <> show actualMajor, + "-D" <> macroName settings <> "_MINOR=" <> show actualMinor, + "-D" <> macroName settings <> "_PATCH=" <> show actualPatch, + "-D" <> macroName settings <> "_IS_AT_LEAST(a,b,c)=(" <> show actualMajor <> ">a||(" <> show actualMajor <> "==a&&(" <> show actualMinor <> ">b||(" <> show actualMinor <> "==b&&" <> show actualPatch <> ">=c))))" + ] + extraFlags = + [ (mkFlagName (flagPrefixName settings ++ "-" ++ show major ++ "_" ++ show minor), (actualMajor, actualMinor) >= (major, minor)) + | declaredFlag <- genericPackageDescription ^. genPackageFlags, + let rawName = unFlagName $ flagName declaredFlag, + rawVersion <- L.stripPrefix (flagPrefixName settings ++ "-") rawName & toList, + [major, minor] <- unambiguously parseFlagVersion rawVersion & toList + ] + setDefines comp x = + x + & comp . cppOptions %~ (<> defines) + & comp . ccOptions %~ (<> defines) + & comp . cxxOptions %~ (<> defines) + genericPackageDescription' = + genericPackageDescription + & setDefines (condLibrary . traverse . traverse) + & setDefines (condSubLibraries . traverse . traverse . traverse) + & setDefines (condForeignLibs . traverse . traverse . traverse) + & setDefines (condExecutables . traverse . traverse . traverse) + & setDefines (condTestSuites . traverse . traverse . traverse) + & setDefines (condBenchmarks . traverse . traverse . traverse) + + configConfigurationsFlags' = configConfigurationsFlags confFlags `mappend` mkFlagAssignment extraFlags + confFlags' = + confFlags + { configConfigurationsFlags = configConfigurationsFlags' + } + origHook (genericPackageDescription', hookedBuildInfo) confFlags' + +parseVersion :: P.ReadP [Int] +parseVersion = do + map read <$> do + P.many1 (P.satisfy C.isDigit) `P.sepBy` P.char '.' + +parseFlagVersion :: P.ReadP [Int] +parseFlagVersion = + map read <$> do + P.many1 (P.satisfy C.isDigit) `P.sepBy` P.char '_' + +unambiguously :: P.ReadP a -> String -> Maybe a +unambiguously p s = + case filter (\(a, x) -> x == "") $ P.readP_to_S p s of + [(v, _)] -> Just v + _ -> Nothing + +getPkgConfigPackageVersion :: String -> IO (Int, Int, Int) +getPkgConfigPackageVersion pkgName = do + s <- readProcess "pkg-config" ["--modversion", pkgName] "" + case L.sortOn (\(_, s) -> length s) $ P.readP_to_S parseVersion s of + [] -> error ("Could not parse version " ++ show s ++ " returned by pkg-config for package " ++ pkgName) + (v, r) : _ -> do + when (L.dropWhile C.isSpace r /= "") $ do + log ("ignoring trailing text " ++ show r ++ " in version " ++ show s ++ " of pkg-config package " ++ pkgName) + let v' = v ++ L.repeat 0 + pure (v' L.!! 0, v' L.!! 1, v' L.!! 2) + +-- Should probably use a Cabal function? +log = hPutStrLn stderr