Skip to content
This repository

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Octocat-spinner-32-eaf2f5

Cannot retrieve contributors at this time

file 219 lines (191 sloc) 8.832 kb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218
-----------------------------------------------------------------------------
-- |
-- Module : Distribution.Client.Index
-- Maintainer : cabal-devel@haskell.org
-- Portability : portable
--
-- Querying and modifying local build tree references in the package index.
-----------------------------------------------------------------------------

module Distribution.Client.Index (
    index,

    createEmpty,
    addBuildTreeRefs,
    removeBuildTreeRefs,
    listBuildTreeRefs,

    defaultIndexFileName
  ) where

import qualified Distribution.Client.Tar as Tar
import Distribution.Client.IndexUtils ( getSourcePackages )
import Distribution.Client.PackageIndex ( allPackages )
import Distribution.Client.Setup ( IndexFlags(..) )
import Distribution.Client.Types ( Repo(..), LocalRepo(..)
                                 , SourcePackageDb(..)
                                 , SourcePackage(..), PackageLocation(..) )
import Distribution.Client.Utils ( byteStringToFilePath, filePathToByteString
                                 , makeAbsoluteToCwd )

import Distribution.Simple.Setup ( fromFlagOrDefault )
import Distribution.Simple.Utils ( die, debug, notice, findPackageDesc )
import Distribution.Verbosity ( Verbosity )

import qualified Data.ByteString.Lazy as BS
import Control.Exception ( evaluate )
import Control.Monad ( liftM, when, unless )
import Data.List ( (\\), nub )
import Data.Maybe ( catMaybes )
import System.Directory ( canonicalizePath, createDirectoryIfMissing,
                                   doesDirectoryExist, doesFileExist,
                                   renameFile )
import System.FilePath ( (</>), (<.>), takeDirectory, takeExtension )
import System.IO ( IOMode(..), SeekMode(..)
                                 , hSeek, withBinaryFile )

-- | A reference to a local build tree.
newtype BuildTreeRef = BuildTreeRef {
  buildTreePath :: FilePath
  }

defaultIndexFileName :: FilePath
defaultIndexFileName = "00-index.tar"

-- | Entry point for the 'cabal index' command.
index :: Verbosity -> IndexFlags -> FilePath -> IO ()
index verbosity indexFlags path' = do
  let runInit = fromFlagOrDefault False (indexInit indexFlags)
  let refsToAdd = indexLinkSource indexFlags
  let runLinkSource = not . null $ refsToAdd
  let refsToRemove = indexRemoveSource indexFlags
  let runRemoveSource = not . null $ refsToRemove
  let runList = fromFlagOrDefault False (indexList indexFlags)

  unless (or [runInit, runLinkSource, runRemoveSource, runList]) $ do
    die "no arguments passed to the 'index' command"

  path <- validateIndexPath path'

  when runInit $ do
    createEmpty verbosity path

  when runLinkSource $ do
    addBuildTreeRefs verbosity path refsToAdd

  when runRemoveSource $ do
    removeBuildTreeRefs verbosity path refsToRemove

  when runList $ do
    refs <- listBuildTreeRefs verbosity path
    mapM_ putStrLn refs

-- | Given a path, ensure that it refers to a local build tree.
buildTreeRefFromPath :: FilePath -> IO (Maybe BuildTreeRef)
buildTreeRefFromPath dir = do
  dirExists <- doesDirectoryExist dir
  when (not dirExists) $ do
    die $ "directory '" ++ dir ++ "' does not exist"
  _ <- findPackageDesc dir
  return . Just $ BuildTreeRef { buildTreePath = dir }

-- | Given a tar archive entry, try to parse it as a local build tree reference.
readBuildTreePath :: Tar.Entry -> Maybe FilePath
readBuildTreePath entry = case Tar.entryContent entry of
  (Tar.OtherEntryType typeCode bs size)
    | (typeCode == Tar.buildTreeRefTypeCode)
      && (size == BS.length bs) -> Just $ byteStringToFilePath bs
    | otherwise -> Nothing
  _ -> Nothing

-- | Given a sequence of tar archive entries, extract all references to local
-- build trees.
readBuildTreePaths :: Tar.Entries -> [FilePath]
readBuildTreePaths =
  catMaybes
  . Tar.foldrEntries (\e r -> (readBuildTreePath e):r)
  [] error

-- | Given a path to a tar archive, extract all references to local build trees.
readBuildTreePathsFromFile :: FilePath -> IO [FilePath]
readBuildTreePathsFromFile = liftM (readBuildTreePaths . Tar.read)
                                  . BS.readFile

-- | Given a local build tree, serialise it to a tar archive entry.
writeBuildTreeRef :: BuildTreeRef -> Tar.Entry
writeBuildTreeRef lbt = Tar.simpleEntry tarPath content
  where
    bs = filePathToByteString path
    path = buildTreePath lbt
    -- fromRight can't fail because the path is shorter than 255 characters.
    tarPath = fromRight $ Tar.toTarPath True tarPath'
    -- Provide a filename for tools that treat custom entries as ordinary files.
    tarPath' = "local-build-tree-reference"
    content = Tar.OtherEntryType Tar.buildTreeRefTypeCode bs (BS.length bs)

    -- TODO: Move this to D.C.Utils?
    fromRight (Left err) = error err
    fromRight (Right a) = a

-- | Check that the provided path is either an existing directory, or a tar
-- archive in an existing directory.
validateIndexPath :: FilePath -> IO FilePath
validateIndexPath path' = do
   path <- makeAbsoluteToCwd path'
   if (== ".tar") . takeExtension $ path
     then return path
     else do dirExists <- doesDirectoryExist path
             unless dirExists $ do
               die $ "directory does not exist: '" ++ path ++ "'"
             return $ path </> defaultIndexFileName

-- | Create an empty index file.
createEmpty :: Verbosity -> FilePath -> IO ()
createEmpty verbosity path = do
  indexExists <- doesFileExist path
  if indexExists
    then debug verbosity $ "Package index already exists: " ++ path
    else do
    debug verbosity $ "Creating the index file '" ++ path ++ "'"
    createDirectoryIfMissing True (takeDirectory path)
    -- Equivalent to 'tar cvf empty.tar --files-from /dev/null'.
    let zeros = BS.replicate (512*20) 0
    BS.writeFile path zeros

-- | Add given local build tree references to the index.
addBuildTreeRefs :: Verbosity -> FilePath -> [FilePath] -> IO ()
addBuildTreeRefs _ _ [] =
  error "Distribution.Client.Index.addBuildTreeRefs: unexpected"
addBuildTreeRefs verbosity path l' = do
  checkIndexExists path
  l <- liftM nub . mapM canonicalizePath $ l'
  treesInIndex <- readBuildTreePathsFromFile path
  -- Add only those paths that aren't already in the index.
  treesToAdd <- mapM buildTreeRefFromPath (l \\ treesInIndex)
  let entries = map writeBuildTreeRef (catMaybes treesToAdd)
  when (not . null $ entries) $ do
    offset <-
      fmap (Tar.foldrEntries (\e acc -> Tar.entrySizeInBytes e + acc) 0 error
            . Tar.read) $ BS.readFile path
    _ <- evaluate offset
    debug verbosity $ "Writing at offset: " ++ show offset
    withBinaryFile path ReadWriteMode $ \h -> do
      hSeek h AbsoluteSeek (fromIntegral offset)
      BS.hPut h (Tar.write entries)
      debug verbosity $ "Successfully appended to '" ++ path ++ "'"

-- | Remove given local build tree references from the index.
removeBuildTreeRefs :: Verbosity -> FilePath -> [FilePath] -> IO ()
removeBuildTreeRefs _ _ [] =
  error "Distribution.Client.Index.removeBuildTreeRefs: unexpected"
removeBuildTreeRefs verbosity path l' = do
  checkIndexExists path
  l <- mapM canonicalizePath l'
  let tmpFile = path <.> "tmp"
  -- Performance note: on my system, it takes 'index --remove-source'
  -- approx. 3,5s to filter a 65M file. Real-life indices are expected to be
  -- much smaller.
  BS.writeFile tmpFile . Tar.writeEntries . Tar.filterEntries (p l) . Tar.read
    =<< BS.readFile path
  -- This invalidates the cache, so we don't have to update it explicitly.
  renameFile tmpFile path
  debug verbosity $ "Successfully renamed '" ++ tmpFile
    ++ "' to '" ++ path ++ "'"
    where
      p l entry = case readBuildTreePath entry of
        Nothing -> True
        (Just pth) -> not $ any (== pth) l

-- | List the local build trees that are referred to from the index.
listBuildTreeRefs :: Verbosity -> FilePath -> IO [FilePath]
listBuildTreeRefs verbosity path = do
  checkIndexExists path
  let repo = Repo { repoKind = Right LocalRepo
                  , repoLocalDir = takeDirectory path }
  pkgIndex <- fmap packageIndex . getSourcePackages verbosity $ [repo]
  let buildTreeRefs = [ pkgPath | (LocalUnpackedPackage pkgPath) <-
                           map packageSource . allPackages $ pkgIndex ]
  when (null buildTreeRefs) $ do
    notice verbosity $ "Index file '" ++ path
      ++ "' has no references to local build trees."
  return buildTreeRefs

-- | Check that the package index file exists and exit with error if it does not.
checkIndexExists :: FilePath -> IO ()
checkIndexExists path = do
  indexExists <- doesFileExist path
  when (not indexExists) $ do
    die $ "index does not exist: '" ++ path ++ "'"
Something went wrong with that request. Please try again.