{-# LANGUAGE CPP, BangPatterns, PatternGuards #-}
{-# LANGUAGE GeneralizedNewtypeDeriving, DeriveDataTypeable #-}
-----------------------------------------------------------------------------
-- |
-- Module : Codec.Archive.Tar.Index
-- Copyright : (c) 2010-2015 Duncan Coutts
-- License : BSD3
--
-- Maintainer : duncan@community.haskell.org
-- Portability : portable
--
-- Random access to the content of a @.tar@ archive.
--
-- This module uses common names and so is designed to be imported qualified:
--
-- > import qualified Codec.Archive.Tar.Index as TarIndex
--
-----------------------------------------------------------------------------
module Codec.Archive.Tar.Index (
-- | The @tar@ format does not contain an index of files within the
-- archive. Normally, @tar@ file have to be processed linearly. It is
-- sometimes useful however to be able to get random access to files
-- within the archive.
--
-- This module provides an index of a @tar@ file. A linear pass of the
-- @tar@ file is needed to 'build' the 'TarIndex', but thereafter you can
-- 'lookup' paths in the @tar@ file, and then use 'hReadEntry' to
-- seek to the right part of the file and read the entry.
--
-- An index cannot be used to lookup 'Directory' entries in a tar file;
-- instead, you will get 'TarDir' entry listing all the entries in the
-- directory.
-- * Index type
TarIndex,
-- * Index lookup
lookup,
TarIndexEntry(..),
toList,
-- ** I\/O operations
TarEntryOffset,
hReadEntry,
hReadEntryHeader,
-- * Index construction
build,
-- ** Incremental construction
-- $incremental-construction
IndexBuilder,
empty,
addNextEntry,
skipNextEntry,
finalise,
unfinalise,
-- * Serialising indexes
serialise,
deserialise,
-- * Lower level operations with offsets and I\/O on tar files
hReadEntryHeaderOrEof,
hSeekEntryOffset,
hSeekEntryContentOffset,
hSeekEndEntryOffset,
nextEntryOffset,
indexEndEntryOffset,
indexNextEntryOffset,
-- * Deprecated aliases
emptyIndex,
finaliseIndex,
#ifdef TESTS
prop_lookup,
prop_toList,
prop_valid,
prop_serialise_deserialise,
prop_serialiseSize,
prop_index_matches_tar,
prop_finalise_unfinalise,
#endif
) where
import Data.Typeable (Typeable)
import Codec.Archive.Tar.Types as Tar
import Codec.Archive.Tar.Read as Tar
import qualified Codec.Archive.Tar.Index.StringTable as StringTable
import Codec.Archive.Tar.Index.StringTable (StringTable, StringTableBuilder)
import qualified Codec.Archive.Tar.Index.IntTrie as IntTrie
import Codec.Archive.Tar.Index.IntTrie (IntTrie, IntTrieBuilder)
import qualified System.FilePath.Posix as FilePath
import Data.Monoid (Monoid(..))
#if (MIN_VERSION_base(4,5,0))
import Data.Monoid ((<>))
#endif
import Data.Word
import Data.Int
import Data.Bits
import qualified Data.Array.Unboxed as A
import Prelude hiding (lookup)
import System.IO
import Control.Exception (assert, throwIO)
import Control.DeepSeq
import qualified Data.ByteString as BS
import qualified Data.ByteString.Char8 as BS.Char8
import qualified Data.ByteString.Lazy as LBS
import qualified Data.ByteString.Unsafe as BS
#if MIN_VERSION_bytestring(0,10,2) || defined(MIN_VERSION_bytestring_builder)
import Data.ByteString.Builder as BS
import Data.ByteString.Builder.Extra as BS (toLazyByteStringWith,
untrimmedStrategy)
#else
import Data.ByteString.Lazy.Builder as BS
import Data.ByteString.Lazy.Builder.Extras as BS (toLazyByteStringWith,
untrimmedStrategy)
#endif
#ifdef TESTS
import qualified Prelude
import Test.QuickCheck
import Test.QuickCheck.Property (ioProperty)
import Control.Applicative ((<$>), (<*>))
import Control.Monad (unless)
import Data.List (nub, sort, sortBy, stripPrefix, isPrefixOf)
import Data.Maybe
import Data.Function (on)
import Control.Exception (SomeException, try)
import Codec.Archive.Tar.Write as Tar
import qualified Data.ByteString.Handle as HBS
#endif
-- | An index of the entries in a tar file.
--
-- This index type is designed to be quite compact and suitable to store either
-- on disk or in memory.
--
data TarIndex = TarIndex
-- As an example of how the mapping works, consider these example files:
-- "foo/bar.hs" at offset 0
-- "foo/baz.hs" at offset 1024
--
-- We split the paths into components and enumerate them.
-- { "foo" -> TokenId 0, "bar.hs" -> TokenId 1, "baz.hs" -> TokenId 2 }
--
-- We convert paths into sequences of 'TokenId's, i.e.
-- "foo/bar.hs" becomes [PathComponentId 0, PathComponentId 1]
-- "foo/baz.hs" becomes [PathComponentId 0, PathComponentId 2]
--
-- We use a trie mapping sequences of 'PathComponentId's to the entry offset:
-- { [PathComponentId 0, PathComponentId 1] -> offset 0
-- , [PathComponentId 0, PathComponentId 2] -> offset 1024 }
-- The mapping of filepath components as strings to ids.
{-# UNPACK #-} !(StringTable PathComponentId)
-- Mapping of sequences of filepath component ids to tar entry offsets.
{-# UNPACK #-} !(IntTrie PathComponentId TarEntryOffset)
-- The offset immediatly after the last entry, where we would append any
-- additional entries.
{-# UNPACK #-} !TarEntryOffset
deriving (Eq, Show, Typeable)
instance NFData TarIndex where
rnf (TarIndex _ _ _) = () -- fully strict by construction
-- | The result of 'lookup' in a 'TarIndex'. It can either be a file directly,
-- or a directory entry containing further entries (and all subdirectories
-- recursively). Note that the subtrees are constructed lazily, so it's
-- cheaper if you don't look at them.
--
data TarIndexEntry = TarFileEntry {-# UNPACK #-} !TarEntryOffset
| TarDir [(FilePath, TarIndexEntry)]
deriving (Show, Typeable)
newtype PathComponentId = PathComponentId Int
deriving (Eq, Ord, Enum, Show, Typeable)
-- | An offset within a tar file. Use 'hReadEntry', 'hReadEntryHeader' or
-- 'hSeekEntryOffset'.
--
-- This is actually a tar \"record\" number, not a byte offset.
--
type TarEntryOffset = Word32
-- | Look up a given filepath in the 'TarIndex'. It may return a 'TarFileEntry'
-- containing the 'TarEntryOffset' of the file within the tar file, or if
-- the filepath identifies a directory then it returns a 'TarDir' containing
-- the list of files within that directory.
--
-- Given the 'TarEntryOffset' you can then use one of the I\/O operations:
--
-- * 'hReadEntry' to read the whole entry;
--
-- * 'hReadEntryHeader' to read just the file metadata (e.g. its length);
--
lookup :: TarIndex -> FilePath -> Maybe TarIndexEntry
lookup (TarIndex pathTable pathTrie _) path = do
fpath <- toComponentIds pathTable path
tentry <- IntTrie.lookup pathTrie fpath
return (mkIndexEntry tentry)
where
mkIndexEntry (IntTrie.Entry offset) = TarFileEntry offset
mkIndexEntry (IntTrie.Completions entries) =
TarDir [ (fromComponentId pathTable key, mkIndexEntry entry)
| (key, entry) <- entries ]
toComponentIds :: StringTable PathComponentId -> FilePath -> Maybe [PathComponentId]
toComponentIds table =
lookupComponents []
. filter (/= BS.Char8.singleton '.')
. splitDirectories
. BS.Char8.pack
where
lookupComponents cs' [] = Just (reverse cs')
lookupComponents cs' (c:cs) = case StringTable.lookup table c of
Nothing -> Nothing
Just cid -> lookupComponents (cid:cs') cs
fromComponentId :: StringTable PathComponentId -> PathComponentId -> FilePath
fromComponentId table = BS.Char8.unpack . StringTable.index table
-- | All the files in the index with their corresponding 'TarEntryOffset's.
--
-- Note that the files are in no special order. If you intend to read all or
-- most files then is is recommended to sort by the 'TarEntryOffset'.
--
toList :: TarIndex -> [(FilePath, TarEntryOffset)]
toList (TarIndex pathTable pathTrie _) =
[ (path, off)
| (cids, off) <- IntTrie.toList pathTrie
, let path = FilePath.joinPath (map (fromComponentId pathTable) cids) ]
-- | Build a 'TarIndex' from a sequence of tar 'Entries'. The 'Entries' are
-- assumed to start at offset @0@ within a file.
--
build :: Entries e -> Either e TarIndex
build = go empty
where
go !builder (Next e es) = go (addNextEntry e builder) es
go !builder Done = Right $! finalise builder
go !_ (Fail err) = Left err
-- $incremental-construction
-- If you need more control than 'build' then you can construct the index
-- in an acumulator style using the 'IndexBuilder' and operations.
--
-- Start with 'empty' and use 'addNextEntry' (or 'skipNextEntry') for
-- each 'Entry' in the tar file in order. Every entry must added or skipped in
-- order, otherwise the resulting 'TarIndex' will report the wrong
-- 'TarEntryOffset's. At the end use 'finalise' to get the 'TarIndex'.
--
-- For example, 'build' is simply:
--
-- > build = go empty
-- > where
-- > go !builder (Next e es) = go (addNextEntry e builder) es
-- > go !builder Done = Right $! finalise builder
-- > go !_ (Fail err) = Left err
-- | The intermediate type used for incremental construction of a 'TarIndex'.
--
data IndexBuilder
= IndexBuilder !(StringTableBuilder PathComponentId)
!(IntTrieBuilder PathComponentId TarEntryOffset)
{-# UNPACK #-} !TarEntryOffset
deriving (Eq, Show)
instance NFData IndexBuilder where
rnf (IndexBuilder _ _ _) = () -- fully strict by construction
-- | The initial empty 'IndexBuilder'.
--
empty :: IndexBuilder
empty = IndexBuilder StringTable.empty IntTrie.empty 0
emptyIndex :: IndexBuilder
emptyIndex = empty
{-# DEPRECATED emptyIndex "Use TarIndex.empty" #-}
-- | Add the next 'Entry' into the 'IndexBuilder'.
--
addNextEntry :: Entry -> IndexBuilder -> IndexBuilder
addNextEntry entry (IndexBuilder stbl itrie nextOffset) =
IndexBuilder stbl' itrie'
(nextEntryOffset entry nextOffset)
where
!entrypath = splitTarPath (entryTarPath entry)
(stbl', cids) = StringTable.inserts entrypath stbl
itrie' = IntTrie.insert cids nextOffset itrie
-- | Use this function if you want to skip some entries and not add them to the
-- final 'TarIndex'.
--
skipNextEntry :: Entry -> IndexBuilder -> IndexBuilder
skipNextEntry entry (IndexBuilder stbl itrie nextOffset) =
IndexBuilder stbl itrie (nextEntryOffset entry nextOffset)
-- | Finish accumulating 'Entry' information and build the compact 'TarIndex'
-- lookup structure.
--
finalise :: IndexBuilder -> TarIndex
finalise (IndexBuilder stbl itrie finalOffset) =
TarIndex pathTable pathTrie finalOffset
where
pathTable = StringTable.finalise stbl
pathTrie = IntTrie.finalise itrie
finaliseIndex :: IndexBuilder -> TarIndex
finaliseIndex = finalise
{-# DEPRECATED finaliseIndex "Use TarIndex.finalise" #-}
-- | This is the offset immediately following the entry most recently added
-- to the 'IndexBuilder'. You might use this if you need to know the offsets
-- but don't want to use the 'TarIndex' lookup structure.
-- Use with 'hSeekEntryOffset'. See also 'nextEntryOffset'.
--
indexNextEntryOffset :: IndexBuilder -> TarEntryOffset
indexNextEntryOffset (IndexBuilder _ _ off) = off
-- | This is the offset immediately following the last entry in the tar file.
-- This can be useful to append further entries into the tar file.
-- Use with 'hSeekEntryOffset', or just use 'hSeekEndEntryOffset' directly.
--
indexEndEntryOffset :: TarIndex -> TarEntryOffset
indexEndEntryOffset (TarIndex _ _ off) = off
-- | Calculate the 'TarEntryOffset' of the next entry, given the size and
-- offset of the current entry.
--
-- This is much like using 'skipNextEntry' and 'indexNextEntryOffset', but without
-- using an 'IndexBuilder'.
--
nextEntryOffset :: Entry -> TarEntryOffset -> TarEntryOffset
nextEntryOffset entry offset =
offset
+ 1
+ case entryContent entry of
NormalFile _ size -> blocks size
OtherEntryType _ _ size -> blocks size
_ -> 0
where
-- NOTE: to avoid underflow, do the (fromIntegral :: Int64 -> Word32) last
blocks :: Int64 -> TarEntryOffset
blocks size = fromIntegral (1 + (size - 1) `div` 512)
type FilePathBS = BS.ByteString
splitTarPath :: TarPath -> [FilePathBS]
splitTarPath (TarPath name prefix) =
splitDirectories prefix ++ splitDirectories name
splitDirectories :: FilePathBS -> [FilePathBS]
splitDirectories bs =
case BS.Char8.split '/' bs of
c:cs | BS.null c -> BS.Char8.singleton '/' : filter (not . BS.null) cs
cs -> filter (not . BS.null) cs
-------------------------
-- Resume building an existing index
--
-- | Resume building an existing index
--
-- A 'TarIndex' is optimized for a highly compact and efficient in-memory
-- representation. This, however, makes it read-only. If you have an existing
-- 'TarIndex' for a large file, and want to add to it, you can translate the
-- 'TarIndex' back to an 'IndexBuilder'. Be aware that this is a relatively
-- costly operation (linear in the size of the 'TarIndex'), though still
-- faster than starting again from scratch.
--
-- This is the left inverse to 'finalise' (modulo ordering).
--
unfinalise :: TarIndex -> IndexBuilder
unfinalise (TarIndex pathTable pathTrie finalOffset) =
IndexBuilder (StringTable.unfinalise pathTable)
(IntTrie.unfinalise pathTrie)
finalOffset
-------------------------
-- I/O operations
--
-- | Reads an entire 'Entry' at the given 'TarEntryOffset' in the tar file.
-- The 'Handle' must be open for reading and be seekable.
--
-- This reads the whole entry into memory strictly, not incrementally. For more
-- control, use 'hReadEntryHeader' and then read the entry content manually.
--
hReadEntry :: Handle -> TarEntryOffset -> IO Entry
hReadEntry hnd off = do
entry <- hReadEntryHeader hnd off
case entryContent entry of
NormalFile _ size -> do body <- LBS.hGet hnd (fromIntegral size)
return entry {
entryContent = NormalFile body size
}
OtherEntryType c _ size -> do body <- LBS.hGet hnd (fromIntegral size)
return entry {
entryContent = OtherEntryType c body size
}
_ -> return entry
-- | Read the header for a 'Entry' at the given 'TarEntryOffset' in the tar
-- file. The 'entryContent' will contain the correct metadata but an empty file
-- content. The 'Handle' must be open for reading and be seekable.
--
-- The 'Handle' position is advanced to the beginning of the entry content (if
-- any). You must check the 'entryContent' to see if the entry is of type
-- 'NormalFile'. If it is, the 'NormalFile' gives the content length and you
-- are free to read this much data from the 'Handle'.
--
-- > entry <- Tar.hReadEntryHeader hnd
-- > case Tar.entryContent entry of
-- > Tar.NormalFile _ size -> do content <- BS.hGet hnd size
-- > ...
--
-- Of course you don't have to read it all in one go (as 'hReadEntry' does),
-- you can use any appropriate method to read it incrementally.
--
-- In addition to I\/O errors, this can throw a 'FormatError' if the offset is
-- wrong, or if the file is not valid tar format.
--
-- There is also the lower level operation 'hSeekEntryOffset'.
--
hReadEntryHeader :: Handle -> TarEntryOffset -> IO Entry
hReadEntryHeader hnd blockOff = do
hSeekEntryOffset hnd blockOff
header <- LBS.hGet hnd 512
case Tar.read header of
Tar.Next entry _ -> return entry
Tar.Fail e -> throwIO e
Tar.Done -> fail "hReadEntryHeader: impossible"
-- | Set the 'Handle' position to the position corresponding to the given
-- 'TarEntryOffset'.
--
-- This position is where the entry metadata can be read. If you already know
-- the entry has a body (and perhaps know it's length), you may wish to seek to
-- the body content directly using 'hSeekEntryContentOffset'.
--
hSeekEntryOffset :: Handle -> TarEntryOffset -> IO ()
hSeekEntryOffset hnd blockOff =
hSeek hnd AbsoluteSeek (fromIntegral blockOff * 512)
-- | Set the 'Handle' position to the entry content position corresponding to
-- the given 'TarEntryOffset'.
--
-- This position is where the entry content can be read using ordinary I\/O
-- operations (though you have to know in advance how big the entry content
-- is). This is /only valid/ if you /already know/ the entry has a body (i.e.
-- is a normal file).
--
hSeekEntryContentOffset :: Handle -> TarEntryOffset -> IO ()
hSeekEntryContentOffset hnd blockOff =
hSeekEntryOffset hnd (blockOff + 1)
-- | This is a low level variant on 'hReadEntryHeader', that can be used to
-- iterate through a tar file, entry by entry.
--
-- It has a few differences compared to 'hReadEntryHeader':
--
-- * It returns an indication when the end of the tar file is reached.
--
-- * It /does not/ move the 'Handle' position to the beginning of the entry
-- content.
--
-- * It returns the 'TarEntryOffset' of the next entry.
--
-- After this action, the 'Handle' position is not in any useful place. If
-- you want to skip to the next entry, take the 'TarEntryOffset' returned and
-- use 'hReadEntryHeaderOrEof' again. Or if having inspected the 'Entry'
-- header you want to read the entry content (if it has one) then use
-- 'hSeekEntryContentOffset' on the original input 'TarEntryOffset'.
--
hReadEntryHeaderOrEof :: Handle -> TarEntryOffset
-> IO (Maybe (Entry, TarEntryOffset))
hReadEntryHeaderOrEof hnd blockOff = do
hSeekEntryOffset hnd blockOff
header <- LBS.hGet hnd 1024
case Tar.read header of
Tar.Next entry _ -> let !blockOff' = nextEntryOffset entry blockOff
in return (Just (entry, blockOff'))
Tar.Done -> return Nothing
Tar.Fail e -> throwIO e
-- | Seek to the end of a tar file, to the position where new entries can
-- be appended, and return that 'TarEntryOffset'.
--
-- If you have a valid 'TarIndex' for this tar file then you should supply it
-- because it allows seeking directly to the correct location.
--
-- If you do not have an index, then this becomes an expensive linear
-- operation because we have to read each tar entry header from the beginning
-- to find the location immediately after the last entry (this is because tar
-- files have a variable length trailer and we cannot reliably find that by
-- starting at the end). In this mode, it will fail with an exception if the
-- file is not in fact in the tar format.
--
hSeekEndEntryOffset :: Handle -> Maybe TarIndex -> IO TarEntryOffset
hSeekEndEntryOffset hnd (Just index) = do
let offset = indexEndEntryOffset index
hSeekEntryOffset hnd offset
return offset
hSeekEndEntryOffset hnd Nothing = do
size <- hFileSize hnd
if size == 0
then return 0
else seekToEnd 0
where
seekToEnd offset = do
mbe <- hReadEntryHeaderOrEof hnd offset
case mbe of
Nothing -> do hSeekEntryOffset hnd offset
return offset
Just (_, offset') -> seekToEnd offset'
-------------------------
-- (de)serialisation
--
-- | The 'TarIndex' is compact in memory, and it has a similarly compact
-- external representation.
--
serialise :: TarIndex -> BS.ByteString
serialise = toStrict . serialiseLBS
-- we keep this version around just so we can check we got the size right.
serialiseLBS :: TarIndex -> LBS.ByteString
serialiseLBS index =
BS.toLazyByteStringWith
(BS.untrimmedStrategy (serialiseSize index) 512) LBS.empty
(serialiseBuilder index)
serialiseSize :: TarIndex -> Int
serialiseSize (TarIndex stringTable intTrie _) =
StringTable.serialiseSize stringTable
+ IntTrie.serialiseSize intTrie
+ 8
serialiseBuilder :: TarIndex -> BS.Builder
serialiseBuilder (TarIndex stringTable intTrie finalOffset) =
BS.word32BE 2 -- format version
<> BS.word32BE finalOffset
<> StringTable.serialise stringTable
<> IntTrie.serialise intTrie
-- | Read the external representation back into a 'TarIndex'.
--
deserialise :: BS.ByteString -> Maybe (TarIndex, BS.ByteString)
deserialise bs
| BS.length bs < 8
= Nothing
| let ver = readWord32BE bs 0
, ver == 1
= do let !finalOffset = readWord32BE bs 4
(stringTable, bs') <- StringTable.deserialiseV1 (BS.drop 8 bs)
(intTrie, bs'') <- IntTrie.deserialise bs'
return (TarIndex stringTable intTrie finalOffset, bs'')
| let ver = readWord32BE bs 0
, ver == 2
= do let !finalOffset = readWord32BE bs 4
(stringTable, bs') <- StringTable.deserialiseV2 (BS.drop 8 bs)
(intTrie, bs'') <- IntTrie.deserialise bs'
return (TarIndex stringTable intTrie finalOffset, bs'')
| otherwise = Nothing
readWord32BE :: BS.ByteString -> Int -> Word32
readWord32BE bs i =
assert (i >= 0 && i+3 <= BS.length bs - 1) $
fromIntegral (BS.unsafeIndex bs (i + 0)) `shiftL` 24
+ fromIntegral (BS.unsafeIndex bs (i + 1)) `shiftL` 16
+ fromIntegral (BS.unsafeIndex bs (i + 2)) `shiftL` 8
+ fromIntegral (BS.unsafeIndex bs (i + 3))
-------------------------
-- Test properties
--
#ifdef TESTS
-- Not quite the properties of a finite mapping because we also have lookups
-- that result in completions.
prop_lookup :: ValidPaths -> NonEmptyFilePath -> Bool
prop_lookup (ValidPaths paths) (NonEmptyFilePath p) =
case (lookup index p, Prelude.lookup p paths) of
(Nothing, Nothing) -> True
(Just (TarFileEntry offset), Just (_,offset')) -> offset == offset'
(Just (TarDir entries), Nothing) -> sort (nub (map fst entries))
== sort (nub completions)
_ -> False
where
index = construct paths
completions = [ head (FilePath.splitDirectories completion)
| (path,_) <- paths
, completion <- maybeToList $ stripPrefix (p ++ "/") path ]
prop_toList :: ValidPaths -> Bool
prop_toList (ValidPaths paths) =
sort (toList index)
== sort [ (path, off) | (path, (_sz, off)) <- paths ]
where
index = construct paths
prop_valid :: ValidPaths -> Bool
prop_valid (ValidPaths paths)
| not $ StringTable.prop_valid pathbits = error "TarIndex: bad string table"
| not $ IntTrie.prop_lookup intpaths = error "TarIndex: bad int trie"
| not $ IntTrie.prop_completions intpaths = error "TarIndex: bad int trie"
| not $ prop' = error "TarIndex: bad prop"
| otherwise = True
where
index@(TarIndex pathTable _ _) = construct paths
pathbits = concatMap (map BS.Char8.pack . FilePath.splitDirectories . fst)
paths
intpaths = [ (cids, offset)
| (path, (_size, offset)) <- paths
, let Just cids = toComponentIds pathTable path ]
prop' = flip all paths $ \(file, (_size, offset)) ->
case lookup index file of
Just (TarFileEntry offset') -> offset' == offset
_ -> False
prop_serialise_deserialise :: ValidPaths -> Bool
prop_serialise_deserialise (ValidPaths paths) =
Just (index, BS.empty) == (deserialise . serialise) index
where
index = construct paths
prop_serialiseSize :: ValidPaths -> Bool
prop_serialiseSize (ValidPaths paths) =
case (LBS.toChunks . serialiseLBS) index of
[c1] -> BS.length c1 == serialiseSize index
_ -> False
where
index = construct paths
newtype NonEmptyFilePath = NonEmptyFilePath FilePath deriving Show
instance Arbitrary NonEmptyFilePath where
arbitrary = NonEmptyFilePath . FilePath.joinPath
<$> listOf1 (elements ["a", "b", "c", "d"])
newtype ValidPaths = ValidPaths [(FilePath, (Int64, TarEntryOffset))] deriving Show
instance Arbitrary ValidPaths where
arbitrary = do
paths <- makeNoPrefix <$> listOf arbitraryPath
sizes <- vectorOf (length paths) (getNonNegative <$> arbitrary)
let offsets = scanl (\o sz -> o + 1 + blocks sz) 0 sizes
return (ValidPaths (zip paths (zip sizes offsets)))
where
arbitraryPath = FilePath.joinPath
<$> listOf1 (elements ["a", "b", "c", "d"])
makeNoPrefix [] = []
makeNoPrefix (k:ks)
| all (not . isPrefixOfOther k) ks
= k : makeNoPrefix ks
| otherwise = makeNoPrefix ks
isPrefixOfOther a b = a `isPrefixOf` b || b `isPrefixOf` a
blocks :: Int64 -> TarEntryOffset
blocks size = fromIntegral (1 + ((size - 1) `div` 512))
-- Helper for bulk construction.
construct :: [(FilePath, (Int64, TarEntryOffset))] -> TarIndex
construct =
either (\_ -> undefined) id
. build
. foldr (\(path, (size, _off)) es -> Next (testEntry path size) es) Done
example0 :: Entries ()
example0 =
testEntry "foo-1.0/foo-1.0.cabal" 1500 -- at block 0
`Next` testEntry "foo-1.0/LICENSE" 2000 -- at block 4
`Next` testEntry "foo-1.0/Data/Foo.hs" 1000 -- at block 9
`Next` Done
example1 :: Entries ()
example1 =
Next (testEntry "./" 1500) Done <> example0
testEntry :: FilePath -> Int64 -> Entry
testEntry name size = simpleEntry path (NormalFile mempty size)
where
Right path = toTarPath False name
-- | Simple tar archive containing regular files only
data SimpleTarArchive = SimpleTarArchive {
simpleTarEntries :: Tar.Entries ()
, simpleTarRaw :: [(FilePath, LBS.ByteString)]
, simpleTarBS :: LBS.ByteString
}
instance Show SimpleTarArchive where
show = show . simpleTarRaw
prop_index_matches_tar :: SimpleTarArchive -> Property
prop_index_matches_tar sta =
ioProperty (try go >>= either (\e -> throwIO (e :: SomeException))
(\_ -> return True))
where
go :: IO ()
go = do
h <- HBS.readHandle True (simpleTarBS sta)
goEntries h 0 (simpleTarEntries sta)
goEntries :: Handle -> TarEntryOffset -> Tar.Entries () -> IO ()
goEntries _ _ Tar.Done =
return ()
goEntries _ _ (Tar.Fail _) =
throwIO (userError "Fail entry in SimpleTarArchive")
goEntries h offset (Tar.Next e es) = do
goEntry h offset e
goEntries h (nextEntryOffset e offset) es
goEntry :: Handle -> TarEntryOffset -> Tar.Entry -> IO ()
goEntry h offset e = do
e' <- hReadEntry h offset
case (Tar.entryContent e, Tar.entryContent e') of
(Tar.NormalFile bs sz, Tar.NormalFile bs' sz') ->
unless (sz == sz' && bs == bs') $
throwIO $ userError "Entry mismatch"
_otherwise ->
throwIO $ userError "unexpected entry types"
instance Arbitrary SimpleTarArchive where
arbitrary = do
numEntries <- sized $ \n -> choose (0, n)
rawEntries <- mkRaw numEntries
let entries = mkList rawEntries
return SimpleTarArchive {
simpleTarEntries = mkEntries entries
, simpleTarRaw = rawEntries
, simpleTarBS = Tar.write entries
}
where
mkRaw :: Int -> Gen [(FilePath, LBS.ByteString)]
mkRaw 0 = return []
mkRaw n = do
-- Pick a size around 0, 1, or 2 block boundaries
sz <- sized $ \n -> elements (take n fileSizes)
bs <- LBS.pack `fmap` vectorOf sz arbitrary
es <- mkRaw (n - 1)
return $ ("file" ++ show n, bs) : es
mkList :: [(FilePath, LBS.ByteString)] -> [Tar.Entry]
mkList [] = []
mkList ((fp, bs):es) = entry : mkList es
where
Right path = toTarPath False fp
entry = simpleEntry path content
content = NormalFile bs (LBS.length bs)
mkEntries :: [Tar.Entry] -> Tar.Entries ()
mkEntries [] = Tar.Done
mkEntries (e:es) = Tar.Next e (mkEntries es)
-- Sizes around 0, 1, and 2 block boundaries
fileSizes :: [Int]
fileSizes = [
0 , 1 , 2
, 510 , 511 , 512 , 513 , 514
, 1022 , 1023 , 1024 , 1025 , 1026
]
-- | 'IndexBuilder' constructed from a 'SimpleIndex'
newtype SimpleIndexBuilder = SimpleIndexBuilder IndexBuilder
deriving Show
instance Arbitrary SimpleIndexBuilder where
arbitrary = SimpleIndexBuilder . build' . simpleTarEntries <$> arbitrary
where
-- like 'build', but don't finalize
build' :: Show e => Entries e -> IndexBuilder
build' = go empty
where
go !builder (Next e es) = go (addNextEntry e builder) es
go !builder Done = builder
go !_ (Fail err) = error (show err)
prop_finalise_unfinalise :: SimpleIndexBuilder -> Bool
prop_finalise_unfinalise (SimpleIndexBuilder index) =
unfinalise (finalise index) == index
#endif
toStrict :: LBS.ByteString -> BS.ByteString
#if MIN_VERSION_bytestring(0,10,0)
toStrict = LBS.toStrict
#else
toStrict = BS.concat . LBS.toChunks
#endif
#if !(MIN_VERSION_base(4,5,0))
(<>) :: Monoid m => m -> m -> m
(<>) = mappend
#endif