--  Copyright (C) 2009-2011 Petr Rockai
--            (C) 2013 Jose Neder
--  BSD3
{-# LANGUAGE CPP, MultiParamTypeClasses #-}

-- | This module contains plain tree indexing code. The index itself is a
-- CACHE: you should only ever use it as an optimisation and never as a primary
-- storage. In practice, this means that when we change index format, the
-- application is expected to throw the old index away and build a fresh
-- index. Please note that tracking index validity is out of scope for this
-- library: this is responsibility of your application. It is advisable that in
-- your validity tracking code, you also check for format validity (see
-- 'indexFormatValid') and scrap and re-create index when needed.
--
-- The index is a binary file that overlays a hashed tree over the working
-- copy. This means that every working file and directory has an entry in the
-- index, that contains its path and hash and validity data. The validity data
-- is a timestamp plus the file size. The file hashes are sha256's of the
-- file's content. It also contains the fileid to track moved files.
--
-- There are two entry types, a file entry and a directory entry. Both have a
-- common binary format (see 'Item'). The on-disk format is best described by
-- the section /Index format/ below.
--
-- For each file, the index has a copy of the file's last modification
-- timestamp taken at the instant when the hash has been computed. This means
-- that when file size and timestamp of a file in working tree matches those in
-- the index, we assume that the hash stored in the index for given file is
-- valid. These hashes are then exposed in the resulting 'Tree' object, and can
-- be leveraged by eg.  'diffTrees' to compare many files quickly.
--
-- You may have noticed that we also keep hashes of directories. These are
-- assumed to be valid whenever the complete subtree has been valid. At any
-- point, as soon as a size or timestamp mismatch is found, the working file in
-- question is opened, its hash (and timestamp and size) is recomputed and
-- updated in-place in the index file (everything lives at a fixed offset and
-- is fixed size, so this isn't an issue). This is also true of directories:
-- when a file in a directory changes hash, this triggers recomputation of all
-- of its parent directory hashes; moreover this is done efficiently -- each
-- directory is updated at most once during an update run.
--
-- /Endianness/
--
-- Since version 6 (magic == "HSI6"), the file format depends on the endianness
-- of the architecture. To account for the (rare) case where darcs executables
-- from different architectures operate on the same repo, we make an additional
-- check in indexFormatValid to detect whether the file's endianness differs
-- from what we expect. If this is detected, the file is considered invalid and
-- will be re-created.
--
-- /Index format/
--
-- The index starts with a header consisting of a 4 bytes magic word, followed
-- by a 4 byte word to indicate the endianness of the encoding. This word
-- should, when read directly from the mmapped file, be equal to 1. After the
-- header comes the actual content of the index, which is organised into
-- \"lines\" where each line describes a single indexed item. It consists of
--
-- * size: item size, 8 bytes
-- * aux: timestamp (for file) or offset to sibling (for dir), 8 bytes
-- * fileid: inode or fhandle of the item, 8 bytes
-- * hash: sha256 of content, 32 bytes
-- * descriptor length: >= 2 due to type and null, 4 bytes
-- * descriptor:
--   * type: 'D' or 'F', one byte
--   * path: flattened path, variable >= 0
-- * null: terminating null byte
--
-- With directories, the aux holds the offset of the next sibling line in the
-- index, so we can efficiently skip reading the whole subtree starting at a
-- given directory (by just seeking aux bytes forward). The lines are
-- pre-ordered with respect to directory structure -- the directory comes first
-- and after it come all its items. Cf. 'openIndex''.
--
-- For files, the aux field holds a timestamp.
--
-- Internally, the item is stored as a pointer to the first field (iBase)
-- from which we directly read off the first three fields (size, aux, fileid),
-- and a ByteString for the rest (iHashAndDescriptor), up to but not including
-- the terminating null byte.
--
-- Comments by bf:
--
-- The null byte terminator seems useless.
--
-- We could as well use just a single ByteString to represent an item; or even
-- a single raw pointer, since finalizers are needed only when we copy hash and
-- path back to the program as ByteStrings.
--
-- An alternative representation could be to store the fixed-size fields (i.e
-- everything except the path) as an unboxed array of records (structs). The
-- paths would then be stored in a bidirectional map between item indices and
-- paths.

module Darcs.Util.Index
    ( openIndex
    , updateIndexFrom
    , indexFormatValid
    , treeFromIndex
    , listFileIDs
    , Index
    , filter
    , getFileID
    -- for testing
    , align
    ) where

import Darcs.Prelude hiding ( readFile, writeFile, filter )

import Darcs.Util.ByteString ( readSegment, decodeLocale )
import qualified Darcs.Util.File ( getFileStatus )
import Darcs.Util.Hash( sha256, rawHash )
import Darcs.Util.Tree
import Darcs.Util.Path
    ( AnchoredPath
    , anchorPath
    , anchoredRoot
    , Name
    , rawMakeName
    , appendPath
    , flatten
    )
import Control.Monad( when )
import Control.Exception( catch, throw, SomeException, Exception )

import qualified Data.ByteString as B
import qualified Data.ByteString.Char8 as BC
import Data.ByteString.Unsafe( unsafeHead, unsafeDrop )
import Data.ByteString.Internal
    ( c2w
    , fromForeignPtr
    , memcpy
    , nullForeignPtr
    , toForeignPtr
    )

import Data.Int( Int64, Int32 )
import Data.IORef( )
import Data.Maybe( fromJust, isJust, fromMaybe )
import Data.Typeable( Typeable )

import Foreign.Storable
import Foreign.ForeignPtr( ForeignPtr, withForeignPtr, castForeignPtr )
import Foreign.Ptr( Ptr, plusPtr )

import System.IO ( hPutStrLn, stderr )
import System.IO.MMap( mmapFileForeignPtr, Mode(..) )
import System.Directory( doesFileExist, getCurrentDirectory, doesDirectoryExist )
import System.Directory( renameFile )
import System.FilePath( (<.>) )

#ifdef WIN32
import System.Win32.File
    ( BY_HANDLE_FILE_INFORMATION(..)
    , closeHandle
    , createFile
    , fILE_FLAG_BACKUP_SEMANTICS
    , fILE_SHARE_NONE
    , gENERIC_NONE
    , getFileInformationByHandle
    , oPEN_EXISTING
    )
#else
import qualified System.Posix.Files as F ( getSymbolicLinkStatus, fileID )
#endif

import System.FilePath ( (</>) )
import qualified System.Posix.Files as F
    ( modificationTime, fileSize, isDirectory, isSymbolicLink
    , FileStatus
    )
import System.Posix.Types ( FileID, EpochTime, FileOffset )

--------------------------
-- Indexed trees
--

-- | Description of a a single indexed item. The structure itself does not
-- contain any data, just pointers to the underlying mmap (bytestring is a
-- pointer + offset + length).
--
-- The structure is recursive-ish (as opposed to flat-ish structure, which is
-- used by git...) It turns out that it's hard to efficiently read a flat index
-- with our internal data structures -- we need to turn the flat index into a
-- recursive Tree object, which is rather expensive... As a bonus, we can also
-- efficiently implement subtree queries this way (cf. 'openIndex').
data Item = Item { Item -> Ptr ()
iBase :: !(Ptr ())
                 , Item -> ByteString
iHashAndDescriptor :: !B.ByteString
                 } deriving Int -> Item -> ShowS
[Item] -> ShowS
Item -> String
forall a.
(Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
showList :: [Item] -> ShowS
$cshowList :: [Item] -> ShowS
show :: Item -> String
$cshow :: Item -> String
showsPrec :: Int -> Item -> ShowS
$cshowsPrec :: Int -> Item -> ShowS
Show

index_version :: B.ByteString
index_version :: ByteString
index_version = String -> ByteString
BC.pack String
"HSI6"

-- | Stored to the index to verify we are on the same endianness when reading
-- it back. We will treat the index as invalid in this case so user code will
-- regenerate it.
index_endianness_indicator :: Int32
index_endianness_indicator :: Int32
index_endianness_indicator = Int32
1

size_header, size_magic, size_endianness_indicator :: Int
size_magic :: Int
size_magic = Int
4 -- the magic word, first 4 bytes of the index
size_endianness_indicator :: Int
size_endianness_indicator = Int
4 -- second 4 bytes of the index
size_header :: Int
size_header = Int
size_magic forall a. Num a => a -> a -> a
+ Int
size_endianness_indicator

size_dsclen, size_hash, size_size, size_aux, size_fileid :: Int
size_size :: Int
size_size = Int
8 -- file/directory size (Int64)
size_aux :: Int
size_aux = Int
8 -- aux (Int64)
size_fileid :: Int
size_fileid = Int
8 -- fileid (inode or fhandle FileID)
size_dsclen :: Int
size_dsclen = Int
4 -- this many bytes store the length of the path
size_hash :: Int
size_hash = Int
32 -- hash representation
size_type, size_null :: Int
size_type :: Int
size_type = Int
1 -- ItemType: 'D' for directory, 'F' for file
size_null :: Int
size_null = Int
1 -- null byte at the end of path

off_size, off_aux, off_hash, off_dsc, off_dsclen, off_fileid :: Int
off_size :: Int
off_size = Int
0
off_aux :: Int
off_aux = Int
off_size forall a. Num a => a -> a -> a
+ Int
size_size
off_fileid :: Int
off_fileid = Int
off_aux forall a. Num a => a -> a -> a
+ Int
size_aux
off_dsclen :: Int
off_dsclen = Int
off_fileid forall a. Num a => a -> a -> a
+ Int
size_fileid
off_hash :: Int
off_hash = Int
off_dsclen forall a. Num a => a -> a -> a
+ Int
size_dsclen
off_dsc :: Int
off_dsc = Int
off_hash forall a. Num a => a -> a -> a
+ Int
size_hash

itemAllocSize :: AnchoredPath -> Int
itemAllocSize :: AnchoredPath -> Int
itemAllocSize AnchoredPath
apath = forall a. Integral a => a -> a -> a
align Int
4 forall a b. (a -> b) -> a -> b
$
  Int
size_size forall a. Num a => a -> a -> a
+ Int
size_aux forall a. Num a => a -> a -> a
+ Int
size_fileid forall a. Num a => a -> a -> a
+ Int
size_dsclen forall a. Num a => a -> a -> a
+ Int
size_hash forall a. Num a => a -> a -> a
+
  Int
size_type forall a. Num a => a -> a -> a
+ ByteString -> Int
B.length (AnchoredPath -> ByteString
flatten AnchoredPath
apath) forall a. Num a => a -> a -> a
+ Int
size_null

itemSize, itemNext :: Item -> Int
itemSize :: Item -> Int
itemSize Item
i =
  Int
size_size forall a. Num a => a -> a -> a
+ Int
size_aux forall a. Num a => a -> a -> a
+ Int
size_fileid forall a. Num a => a -> a -> a
+ Int
size_dsclen forall a. Num a => a -> a -> a
+
  (ByteString -> Int
B.length forall a b. (a -> b) -> a -> b
$ Item -> ByteString
iHashAndDescriptor Item
i)
-- The "+ 1" is for the null byte at the end, which is /not/
-- contained in iDescriptor!
itemNext :: Item -> Int
itemNext Item
i = forall a. Integral a => a -> a -> a
align Int
4 (Item -> Int
itemSize Item
i forall a. Num a => a -> a -> a
+ Int
1)

-- iDescriptor is:
--  * one byte for type of item ('D' or 'F')
--  * flattened path
iHash, iDescriptor :: Item -> B.ByteString
iDescriptor :: Item -> ByteString
iDescriptor = Int -> ByteString -> ByteString
unsafeDrop Int
size_hash forall b c a. (b -> c) -> (a -> b) -> a -> c
. Item -> ByteString
iHashAndDescriptor
iHash :: Item -> ByteString
iHash = Int -> ByteString -> ByteString
B.take Int
size_hash forall b c a. (b -> c) -> (a -> b) -> a -> c
. Item -> ByteString
iHashAndDescriptor

-- The "drop 1" here gets rid of the item type.
iPath :: Item -> FilePath
iPath :: Item -> String
iPath = ByteString -> String
decodeLocale forall b c a. (b -> c) -> (a -> b) -> a -> c
. Int -> ByteString -> ByteString
unsafeDrop Int
1 forall b c a. (b -> c) -> (a -> b) -> a -> c
. Item -> ByteString
iDescriptor

iSize, iAux :: Item -> Ptr Int64
iSize :: Item -> Ptr Int64
iSize Item
i = forall a b. Ptr a -> Int -> Ptr b
plusPtr (Item -> Ptr ()
iBase Item
i) Int
off_size
iAux :: Item -> Ptr Int64
iAux Item
i = forall a b. Ptr a -> Int -> Ptr b
plusPtr (Item -> Ptr ()
iBase Item
i) Int
off_aux

iFileID :: Item -> Ptr FileID
iFileID :: Item -> Ptr FileID
iFileID Item
i = forall a b. Ptr a -> Int -> Ptr b
plusPtr (Item -> Ptr ()
iBase Item
i) Int
off_fileid

itemIsDir :: Item -> Bool
itemIsDir :: Item -> Bool
itemIsDir Item
i = ByteString -> Word8
unsafeHead (Item -> ByteString
iDescriptor Item
i) forall a. Eq a => a -> a -> Bool
== Char -> Word8
c2w Char
'D'

type FileStatus = Maybe F.FileStatus

-- TODO: upgrade to modificationTimeHiRes for nanosecond resolution
modificationTime :: FileStatus -> EpochTime
modificationTime :: FileStatus -> EpochTime
modificationTime = forall b a. b -> (a -> b) -> Maybe a -> b
maybe EpochTime
0 FileStatus -> EpochTime
F.modificationTime

fileSize :: FileStatus -> FileOffset
fileSize :: FileStatus -> FileOffset
fileSize = forall b a. b -> (a -> b) -> Maybe a -> b
maybe FileOffset
0 FileStatus -> FileOffset
F.fileSize

fileExists :: FileStatus -> Bool
fileExists :: FileStatus -> Bool
fileExists = forall b a. b -> (a -> b) -> Maybe a -> b
maybe Bool
False (forall a b. a -> b -> a
const Bool
True)

isDirectory :: FileStatus -> Bool
isDirectory :: FileStatus -> Bool
isDirectory = forall b a. b -> (a -> b) -> Maybe a -> b
maybe Bool
False FileStatus -> Bool
F.isDirectory

-- | Lay out the basic index item structure in memory. The memory location is
-- given by a ForeignPointer () and an offset. The path and type given are
-- written out, and a corresponding Item is given back. The remaining bits of
-- the item can be filled out using 'update'.
createItem :: ItemType -> AnchoredPath -> ForeignPtr () -> Int -> IO Item
createItem :: ItemType -> AnchoredPath -> ForeignPtr () -> Int -> IO Item
createItem ItemType
typ AnchoredPath
apath ForeignPtr ()
fp Int
off = do
  let dsc :: ByteString
dsc =
        [ByteString] -> ByteString
B.concat
          [ Char -> ByteString
BC.singleton forall a b. (a -> b) -> a -> b
$ if ItemType
typ forall a. Eq a => a -> a -> Bool
== ItemType
TreeType then Char
'D' else Char
'F'
          , AnchoredPath -> ByteString
flatten AnchoredPath
apath -- this (currently) gives "." for anchoredRoot
          , Word8 -> ByteString
B.singleton Word8
0
          ]
      (ForeignPtr Word8
dsc_fp, Int
dsc_start, Int
dsc_len) = ByteString -> (ForeignPtr Word8, Int, Int)
toForeignPtr ByteString
dsc
  forall a b. ForeignPtr a -> (Ptr a -> IO b) -> IO b
withForeignPtr ForeignPtr ()
fp forall a b. (a -> b) -> a -> b
$ \Ptr ()
p ->
    forall a b. ForeignPtr a -> (Ptr a -> IO b) -> IO b
withForeignPtr ForeignPtr Word8
dsc_fp forall a b. (a -> b) -> a -> b
$ \Ptr Word8
dsc_p -> do
      FileID
fileid <- forall a. a -> Maybe a -> a
fromMaybe FileID
0 forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> AnchoredPath -> IO (Maybe FileID)
getFileID AnchoredPath
apath
      forall a b. Storable a => Ptr b -> Int -> a -> IO ()
pokeByteOff Ptr ()
p (Int
off forall a. Num a => a -> a -> a
+ Int
off_fileid) (forall a b. (Integral a, Num b) => a -> b
fromIntegral FileID
fileid :: Int64)
      forall a b. Storable a => Ptr b -> Int -> a -> IO ()
pokeByteOff Ptr ()
p (Int
off forall a. Num a => a -> a -> a
+ Int
off_dsclen) (forall a b. (Integral a, Num b) => a -> b
fromIntegral Int
dsc_len :: Int32)
      Ptr Word8 -> Ptr Word8 -> Int -> IO ()
memcpy
        (forall a b. Ptr a -> Int -> Ptr b
plusPtr Ptr ()
p forall a b. (a -> b) -> a -> b
$ Int
off forall a. Num a => a -> a -> a
+ Int
off_dsc)
        (forall a b. Ptr a -> Int -> Ptr b
plusPtr Ptr Word8
dsc_p Int
dsc_start)
        (forall a b. (Integral a, Num b) => a -> b
fromIntegral Int
dsc_len)
      ForeignPtr () -> Int -> IO Item
peekItem ForeignPtr ()
fp Int
off

-- | Read the on-disk representation into internal data structure.
--
-- See the module-level section /Index format/ for details on how the index
-- is structured.
peekItem :: ForeignPtr () -> Int -> IO Item
peekItem :: ForeignPtr () -> Int -> IO Item
peekItem ForeignPtr ()
fp Int
off =
  forall a b. ForeignPtr a -> (Ptr a -> IO b) -> IO b
withForeignPtr ForeignPtr ()
fp forall a b. (a -> b) -> a -> b
$ \Ptr ()
p -> do
    Int32
nl' :: Int32 <- forall a b. Storable a => Ptr b -> Int -> IO a
peekByteOff Ptr ()
p (Int
off forall a. Num a => a -> a -> a
+ Int
off_dsclen)
    forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when (Int32
nl' forall a. Ord a => a -> a -> Bool
<= Int32
2) forall a b. (a -> b) -> a -> b
$ forall (m :: * -> *) a. MonadFail m => String -> m a
fail String
"Descriptor too short in peekItem!"
    let nl :: Int
nl = forall a b. (Integral a, Num b) => a -> b
fromIntegral Int32
nl'
        dsc :: ByteString
dsc =
          ForeignPtr Word8 -> Int -> Int -> ByteString
fromForeignPtr
            (forall a b. ForeignPtr a -> ForeignPtr b
castForeignPtr ForeignPtr ()
fp)
            (Int
off forall a. Num a => a -> a -> a
+ Int
off_hash)
            -- The "- 1" here means we do /not/ include the null byte!
            -- This is why we have to add 1 when we determine the
            -- size, see 'itemSize' and 'itemNext' above.
            (Int
size_hash forall a. Num a => a -> a -> a
+ Int
nl forall a. Num a => a -> a -> a
- Int
1)
    forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$! Item {iBase :: Ptr ()
iBase = forall a b. Ptr a -> Int -> Ptr b
plusPtr Ptr ()
p Int
off, iHashAndDescriptor :: ByteString
iHashAndDescriptor = ByteString
dsc}

-- | Update an existing item with new hash and optionally mtime (give Nothing
-- when updating directory entries).
updateItem :: Item -> Int64 -> Hash -> IO ()
updateItem :: Item -> Int64 -> Hash -> IO ()
updateItem Item
item Int64
_ Hash
NoHash =
    forall (m :: * -> *) a. MonadFail m => String -> m a
fail forall a b. (a -> b) -> a -> b
$ String
"Index.update NoHash: " forall a. [a] -> [a] -> [a]
++ Item -> String
iPath Item
item
updateItem Item
item Int64
size Hash
hash =
    do forall a. Storable a => Ptr a -> a -> IO ()
poke (Item -> Ptr Int64
iSize Item
item) Int64
size
       ByteString -> ByteString -> IO ()
unsafePokeBS (Item -> ByteString
iHash Item
item) (Hash -> ByteString
rawHash Hash
hash)

updateFileID :: Item -> FileID -> IO ()
updateFileID :: Item -> FileID -> IO ()
updateFileID Item
item FileID
fileid = forall a. Storable a => Ptr a -> a -> IO ()
poke (Item -> Ptr FileID
iFileID Item
item) forall a b. (a -> b) -> a -> b
$ forall a b. (Integral a, Num b) => a -> b
fromIntegral FileID
fileid
updateAux :: Item -> Int64 -> IO ()
updateAux :: Item -> Int64 -> IO ()
updateAux Item
item Int64
aux = forall a. Storable a => Ptr a -> a -> IO ()
poke (Item -> Ptr Int64
iAux Item
item) forall a b. (a -> b) -> a -> b
$ Int64
aux
updateTime :: forall a.(Enum a) => Item -> a -> IO ()
updateTime :: forall a. Enum a => Item -> a -> IO ()
updateTime Item
item a
mtime = Item -> Int64 -> IO ()
updateAux Item
item (forall a b. (Integral a, Num b) => a -> b
fromIntegral forall a b. (a -> b) -> a -> b
$ forall a. Enum a => a -> Int
fromEnum a
mtime)

iHash' :: Item -> Hash
iHash' :: Item -> Hash
iHash' Item
i = ByteString -> Hash
SHA256 (Item -> ByteString
iHash Item
i)

-- | Gives a ForeignPtr to mmapped index, which can be used for reading and
-- updates. The req_size parameter, if non-0, expresses the requested size of
-- the index file. mmapIndex will grow the index if it is smaller than this.
mmapIndex :: forall a. FilePath -> Int -> IO (ForeignPtr a, Int)
mmapIndex :: forall a. String -> Int -> IO (ForeignPtr a, Int)
mmapIndex String
indexpath Int
req_size = do
  Int
act_size <- forall a b. (Integral a, Num b) => a -> b
fromIntegral forall b c a. (b -> c) -> (a -> b) -> a -> c
. FileStatus -> FileOffset
fileSize forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> String -> IO FileStatus
Darcs.Util.File.getFileStatus String
indexpath
  let size :: Int
size = case Int
req_size forall a. Ord a => a -> a -> Bool
> Int
0 of
        Bool
True -> Int
req_size
        Bool
False | Int
act_size forall a. Ord a => a -> a -> Bool
>= Int
size_header -> Int
act_size forall a. Num a => a -> a -> a
- Int
size_header
              | Bool
otherwise -> Int
0
  case Int
size of
    Int
0 -> forall (m :: * -> *) a. Monad m => a -> m a
return (forall a b. ForeignPtr a -> ForeignPtr b
castForeignPtr ForeignPtr Word8
nullForeignPtr, Int
size)
    Int
_ -> do (ForeignPtr a
x, Int
_, Int
_) <- forall a.
String -> Mode -> Maybe (Int64, Int) -> IO (ForeignPtr a, Int, Int)
mmapFileForeignPtr String
indexpath
                                            Mode
ReadWriteEx (forall a. a -> Maybe a
Just (Int64
0, Int
size forall a. Num a => a -> a -> a
+ Int
size_header))
            forall (m :: * -> *) a. Monad m => a -> m a
return (ForeignPtr a
x, Int
size)

data IndexM m = Index { forall (m :: * -> *). IndexM m -> ForeignPtr ()
mmap :: (ForeignPtr ())
                      , forall (m :: * -> *). IndexM m -> String
basedir :: FilePath
                      , forall (m :: * -> *). IndexM m -> Tree m -> Hash
hashtree :: Tree m -> Hash
                      , forall (m :: * -> *).
IndexM m -> AnchoredPath -> TreeItem m -> Bool
predicate :: AnchoredPath -> TreeItem m -> Bool }
              | EmptyIndex

type Index = IndexM IO

-- FIXME This is not really a state: we modify it only when we recurse
-- down into a dir item, so this is rather more like an environment.
-- Instead of passing it explicitly we could use ReaderT.

-- | When we traverse the index, we keep track of some data about the
-- current parent directory.
data State = State
  { State -> Int
dirlength :: !Int     -- ^ length in bytes of current path prefix,
                          --   includes the trailing path separator
  , State -> AnchoredPath
path :: !AnchoredPath -- ^ path of the current directory
  , State -> Int
start :: !Int         -- ^ offset of current directory in the index
  }

-- * Reading items from the index

data Result = Result
  { Result -> Bool
changed :: !Bool
  -- ^ Whether item has changed since the last update to the index.
  , Result -> Int
next :: !Int
  -- ^ Position of the next item, in bytes.
  , Result -> Maybe (TreeItem IO)
treeitem :: !(Maybe (TreeItem IO))
  -- ^ Nothing in case of the item doesn't exist in the tree
  -- or is filtered by a FilterTree. Or a TreeItem otherwise.
  , Result -> Item
resitem :: !Item
  -- ^ The item extracted.
  }

readItem :: Index -> State -> IO Result
readItem :: Index -> State -> IO Result
readItem Index
index State
state = do
  Item
item <- ForeignPtr () -> Int -> IO Item
peekItem (forall (m :: * -> *). IndexM m -> ForeignPtr ()
mmap Index
index) (State -> Int
start State
state)
  Result
res' <- if Item -> Bool
itemIsDir Item
item
              then Index -> State -> Item -> IO Result
readDir  Index
index State
state Item
item
              else Index -> State -> Item -> IO Result
readFile Index
index State
state Item
item
  forall (m :: * -> *) a. Monad m => a -> m a
return Result
res'

data CorruptIndex = CorruptIndex String deriving (CorruptIndex -> CorruptIndex -> Bool
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
/= :: CorruptIndex -> CorruptIndex -> Bool
$c/= :: CorruptIndex -> CorruptIndex -> Bool
== :: CorruptIndex -> CorruptIndex -> Bool
$c== :: CorruptIndex -> CorruptIndex -> Bool
Eq, Typeable)
instance Exception CorruptIndex
instance Show CorruptIndex where show :: CorruptIndex -> String
show (CorruptIndex String
s) = String
s

-- | Get the 'Name' of an 'Item' in the given 'State'. This fails for
-- the root 'Item' because it has no 'Name', so we return 'Nothing'.
nameof :: Item -> State -> Maybe Name
nameof :: Item -> State -> Maybe Name
nameof Item
item State
state
  | Item -> ByteString
iDescriptor Item
item forall a. Eq a => a -> a -> Bool
== String -> ByteString
BC.pack String
"D." = forall a. Maybe a
Nothing
  | Bool
otherwise =
      case ByteString -> Either String Name
rawMakeName forall a b. (a -> b) -> a -> b
$ Int -> ByteString -> ByteString
B.drop (State -> Int
dirlength State
state forall a. Num a => a -> a -> a
+ Int
1) forall a b. (a -> b) -> a -> b
$ Item -> ByteString
iDescriptor Item
item of
        Left String
msg -> forall a e. Exception e => e -> a
throw (String -> CorruptIndex
CorruptIndex String
msg)
        Right Name
name -> forall a. a -> Maybe a
Just Name
name

-- | 'Maybe' append a 'Name' to an 'AnchoredPath'.
maybeAppendName :: AnchoredPath -> Maybe Name -> AnchoredPath
maybeAppendName :: AnchoredPath -> Maybe Name -> AnchoredPath
maybeAppendName AnchoredPath
parent = forall b a. b -> (a -> b) -> Maybe a -> b
maybe AnchoredPath
parent (AnchoredPath
parent AnchoredPath -> Name -> AnchoredPath
`appendPath`)

-- | Calculate the next 'State' when entering an 'Item'. Works for the
-- top-level 'Item' i.e. the root directory only because we handle that
-- specially.
substateof :: Item -> State -> State
substateof :: Item -> State -> State
substateof Item
item State
state =
  State
state
    { start :: Int
start = State -> Int
start State
state forall a. Num a => a -> a -> a
+ Item -> Int
itemNext Item
item
    , path :: AnchoredPath
path = State -> AnchoredPath
path State
state AnchoredPath -> Maybe Name -> AnchoredPath
`maybeAppendName` Maybe Name
myname
    , dirlength :: Int
dirlength =
        case Maybe Name
myname of
          Maybe Name
Nothing ->
            -- We are entering the root item. The current path prefix remains
            -- empty, so its length (which must be 0) doesn't change.
            State -> Int
dirlength State
state
          Just Name
_ ->
            -- This works because the 'iDescriptor' is always one byte larger
            -- than the actual name. So @dirlength state@ will also be greater
            -- by 1, which accounts for the path separator when we strip the
            -- directory prefix from the full path.
            ByteString -> Int
B.length (Item -> ByteString
iDescriptor Item
item)
    }
  where
    myname :: Maybe Name
myname = Item -> State -> Maybe Name
nameof Item
item State
state

readDir :: Index -> State -> Item -> IO Result
readDir :: Index -> State -> Item -> IO Result
readDir Index
index State
state Item
item = do
       Int
following <- forall a b. (Integral a, Num b) => a -> b
fromIntegral forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> forall a. Storable a => Ptr a -> IO a
peek (Item -> Ptr Int64
iAux Item
item)
       FileStatus
st <- String -> IO FileStatus
getFileStatus (Item -> String
iPath Item
item)
       let exists :: Bool
exists = FileStatus -> Bool
fileExists FileStatus
st Bool -> Bool -> Bool
&& FileStatus -> Bool
isDirectory FileStatus
st
       FileID
fileid <- forall a b. (Integral a, Num b) => a -> b
fromIntegral forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> (forall a. Storable a => Ptr a -> IO a
peek forall a b. (a -> b) -> a -> b
$ Item -> Ptr FileID
iFileID Item
item)
       FileID
fileid' <- forall a. a -> Maybe a -> a
fromMaybe FileID
fileid forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> (String -> IO (Maybe FileID)
getFileID' forall a b. (a -> b) -> a -> b
$ Item -> String
iPath Item
item)
       forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when (FileID
fileid forall a. Eq a => a -> a -> Bool
== FileID
0) forall a b. (a -> b) -> a -> b
$ Item -> FileID -> IO ()
updateFileID Item
item FileID
fileid'
       let substate :: State
substate = Item -> State -> State
substateof Item
item State
state

           want :: Bool
want = Bool
exists Bool -> Bool -> Bool
&& (forall (m :: * -> *).
IndexM m -> AnchoredPath -> TreeItem m -> Bool
predicate Index
index) (State -> AnchoredPath
path State
substate) (forall (m :: * -> *). m (Tree m) -> Hash -> TreeItem m
Stub forall a. HasCallStack => a
undefined Hash
NoHash)
           oldhash :: Hash
oldhash = Item -> Hash
iHash' Item
item

           subs :: Int -> IO [(Maybe Name, Result)]
subs Int
off =
              case forall a. Ord a => a -> a -> Ordering
compare Int
off Int
following of
                Ordering
LT -> do
                  Result
result <- Index -> State -> IO Result
readItem Index
index forall a b. (a -> b) -> a -> b
$ State
substate { start :: Int
start = Int
off }
                  [(Maybe Name, Result)]
rest <- Int -> IO [(Maybe Name, Result)]
subs forall a b. (a -> b) -> a -> b
$ Result -> Int
next Result
result
                  forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$! (Item -> State -> Maybe Name
nameof (Result -> Item
resitem Result
result) State
substate, Result
result) forall a. a -> [a] -> [a]
: [(Maybe Name, Result)]
rest
                Ordering
EQ -> forall (m :: * -> *) a. Monad m => a -> m a
return []
                Ordering
GT ->
                  forall (m :: * -> *) a. MonadFail m => String -> m a
fail forall a b. (a -> b) -> a -> b
$
                    String
"Offset mismatch at " forall a. [a] -> [a] -> [a]
++ forall a. Show a => a -> String
show Int
off forall a. [a] -> [a] -> [a]
++
                    String
" (ends at " forall a. [a] -> [a] -> [a]
++ forall a. Show a => a -> String
show Int
following forall a. [a] -> [a] -> [a]
++ String
")"

       [(Maybe Name, Result)]
inferiors <- if Bool
want then Int -> IO [(Maybe Name, Result)]
subs forall a b. (a -> b) -> a -> b
$ State -> Int
start State
substate
                            else forall (m :: * -> *) a. Monad m => a -> m a
return []

       let we_changed :: Bool
we_changed = forall (t :: * -> *). Foldable t => t Bool -> Bool
or [ Result -> Bool
changed Result
x | (Maybe Name
_, Result
x) <- [(Maybe Name, Result)]
inferiors ] Bool -> Bool -> Bool
|| Bool
nullleaf
           nullleaf :: Bool
nullleaf = forall (t :: * -> *) a. Foldable t => t a -> Bool
null [(Maybe Name, Result)]
inferiors Bool -> Bool -> Bool
&& Hash
oldhash forall a. Eq a => a -> a -> Bool
== Hash
nullsha
           nullsha :: Hash
nullsha = ByteString -> Hash
SHA256 (Int -> Word8 -> ByteString
B.replicate Int
32 Word8
0)
           tree' :: Tree IO
tree' =
             -- Note the partial pattern match on 'Just n' below is justified
             -- as we are traversing sub items here, which means 'Nothing' is
             -- impossible, see 'substateof' for details.
             forall (m :: * -> *). [(Name, TreeItem m)] -> Tree m
makeTree
               [ (Name
n, forall a. HasCallStack => Maybe a -> a
fromJust forall a b. (a -> b) -> a -> b
$ Result -> Maybe (TreeItem IO)
treeitem Result
s)
               | (Just Name
n, Result
s) <- [(Maybe Name, Result)]
inferiors, forall a. Maybe a -> Bool
isJust forall a b. (a -> b) -> a -> b
$ Result -> Maybe (TreeItem IO)
treeitem Result
s ]
           treehash :: Hash
treehash = if Bool
we_changed then forall (m :: * -> *). IndexM m -> Tree m -> Hash
hashtree Index
index Tree IO
tree' else Hash
oldhash
           tree :: Tree IO
tree = Tree IO
tree' { treeHash :: Hash
treeHash = Hash
treehash }

       forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when (Bool
exists Bool -> Bool -> Bool
&& Bool
we_changed) forall a b. (a -> b) -> a -> b
$ Item -> Int64 -> Hash -> IO ()
updateItem Item
item Int64
0 Hash
treehash
       forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ Result { changed :: Bool
changed = Bool -> Bool
not Bool
exists Bool -> Bool -> Bool
|| Bool
we_changed
                       , next :: Int
next = Int
following
                       , treeitem :: Maybe (TreeItem IO)
treeitem = if Bool
want then forall a. a -> Maybe a
Just forall a b. (a -> b) -> a -> b
$ forall (m :: * -> *). Tree m -> TreeItem m
SubTree Tree IO
tree
                                            else forall a. Maybe a
Nothing
                       , resitem :: Item
resitem = Item
item }

readFile :: Index -> State -> Item -> IO Result
readFile :: Index -> State -> Item -> IO Result
readFile Index
index State
state Item
item = do
       FileStatus
st <- String -> IO FileStatus
getFileStatus (Item -> String
iPath Item
item)
       EpochTime
mtime <- forall a b. (Integral a, Num b) => a -> b
fromIntegral forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> (forall a. Storable a => Ptr a -> IO a
peek forall a b. (a -> b) -> a -> b
$ Item -> Ptr Int64
iAux Item
item)
       Int64
size <- forall a. Storable a => Ptr a -> IO a
peek forall a b. (a -> b) -> a -> b
$ Item -> Ptr Int64
iSize Item
item
       FileID
fileid <- forall a b. (Integral a, Num b) => a -> b
fromIntegral forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> (forall a. Storable a => Ptr a -> IO a
peek forall a b. (a -> b) -> a -> b
$ Item -> Ptr FileID
iFileID Item
item)
       FileID
fileid' <- forall a. a -> Maybe a -> a
fromMaybe FileID
fileid forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> (String -> IO (Maybe FileID)
getFileID' forall a b. (a -> b) -> a -> b
$ Item -> String
iPath Item
item)
       let mtime' :: EpochTime
mtime' = FileStatus -> EpochTime
modificationTime FileStatus
st
           size' :: Int64
size' = forall a b. (Integral a, Num b) => a -> b
fromIntegral forall a b. (a -> b) -> a -> b
$ FileStatus -> FileOffset
fileSize FileStatus
st
           readblob :: IO ByteString
readblob = FileSegment -> IO ByteString
readSegment (forall (m :: * -> *). IndexM m -> String
basedir Index
index String -> ShowS
</> (Item -> String
iPath Item
item), forall a. Maybe a
Nothing)
           exists :: Bool
exists = FileStatus -> Bool
fileExists FileStatus
st Bool -> Bool -> Bool
&& Bool -> Bool
not (FileStatus -> Bool
isDirectory FileStatus
st)
           we_changed :: Bool
we_changed = EpochTime
mtime forall a. Eq a => a -> a -> Bool
/= EpochTime
mtime' Bool -> Bool -> Bool
|| Int64
size forall a. Eq a => a -> a -> Bool
/= Int64
size'
           hash :: Hash
hash = Item -> Hash
iHash' Item
item
       forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when (Bool
exists Bool -> Bool -> Bool
&& Bool
we_changed) forall a b. (a -> b) -> a -> b
$
            do Hash
hash' <- ByteString -> Hash
sha256 forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
`fmap` IO ByteString
readblob
               Item -> Int64 -> Hash -> IO ()
updateItem Item
item Int64
size' Hash
hash'
               forall a. Enum a => Item -> a -> IO ()
updateTime Item
item EpochTime
mtime'
               forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when (FileID
fileid forall a. Eq a => a -> a -> Bool
== FileID
0) forall a b. (a -> b) -> a -> b
$ Item -> FileID -> IO ()
updateFileID Item
item FileID
fileid'
       forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ Result { changed :: Bool
changed = Bool -> Bool
not Bool
exists Bool -> Bool -> Bool
|| Bool
we_changed
                       , next :: Int
next = State -> Int
start State
state forall a. Num a => a -> a -> a
+ Item -> Int
itemNext Item
item
                       , treeitem :: Maybe (TreeItem IO)
treeitem = if Bool
exists then forall a. a -> Maybe a
Just forall a b. (a -> b) -> a -> b
$ forall (m :: * -> *). Blob m -> TreeItem m
File forall a b. (a -> b) -> a -> b
$ forall (m :: * -> *). m ByteString -> Hash -> Blob m
Blob IO ByteString
readblob Hash
hash else forall a. Maybe a
Nothing
                       , resitem :: Item
resitem = Item
item }

-- * Reading (only) file IDs from the index

-- FIXME this seems copy-pasted from the code above and then adapted
-- to the purpose. Should factor out the traversal of the index as a
-- higher order function.

data ResultF = ResultF
  { ResultF -> Int
nextF :: !Int
  -- ^ Position of the next item, in bytes.
  , ResultF -> Item
resitemF :: !Item
  -- ^ The item extracted.
  , ResultF -> [((AnchoredPath, ItemType), FileID)]
_fileIDs :: [((AnchoredPath, ItemType), FileID)]
  -- ^ The fileids of the files and folders inside,
  -- in a folder item and its own fileid for file item).
  }

-- | Return a list containing all the file/folder names in an index, with
-- their respective ItemType and FileID.
listFileIDs :: Index -> IO ([((AnchoredPath, ItemType), FileID)])
listFileIDs :: Index -> IO [((AnchoredPath, ItemType), FileID)]
listFileIDs Index
EmptyIndex = forall (m :: * -> *) a. Monad m => a -> m a
return []
listFileIDs Index
index =
    do let initial :: State
initial = State { start :: Int
start = Int
size_header
                           , dirlength :: Int
dirlength = Int
0
                           , path :: AnchoredPath
path = AnchoredPath
anchoredRoot }
       ResultF
res <- Index -> State -> IO ResultF
readItemFileIDs Index
index State
initial
       forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ ResultF -> [((AnchoredPath, ItemType), FileID)]
_fileIDs ResultF
res

readItemFileIDs :: Index -> State -> IO ResultF
readItemFileIDs :: Index -> State -> IO ResultF
readItemFileIDs Index
index State
state = do
  Item
item <- ForeignPtr () -> Int -> IO Item
peekItem (forall (m :: * -> *). IndexM m -> ForeignPtr ()
mmap Index
index) (State -> Int
start State
state)
  ResultF
res' <- if Item -> Bool
itemIsDir Item
item
              then Index -> State -> Item -> IO ResultF
readDirFileIDs  Index
index State
state Item
item
              else Index -> State -> Item -> IO ResultF
readFileFileID Index
index State
state Item
item
  forall (m :: * -> *) a. Monad m => a -> m a
return ResultF
res'

readDirFileIDs :: Index -> State -> Item -> IO ResultF
readDirFileIDs :: Index -> State -> Item -> IO ResultF
readDirFileIDs Index
index State
state Item
item =
    do FileID
fileid <- forall a b. (Integral a, Num b) => a -> b
fromIntegral forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> (forall a. Storable a => Ptr a -> IO a
peek forall a b. (a -> b) -> a -> b
$ Item -> Ptr FileID
iFileID Item
item)
       Int
following <- forall a b. (Integral a, Num b) => a -> b
fromIntegral forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> forall a. Storable a => Ptr a -> IO a
peek (Item -> Ptr Int64
iAux Item
item)
       let substate :: State
substate = Item -> State -> State
substateof Item
item State
state
           subs :: Int -> IO [(Maybe Name, ResultF)]
subs Int
off =
              case forall a. Ord a => a -> a -> Ordering
compare Int
off Int
following of
                Ordering
LT -> do
                  ResultF
result <- Index -> State -> IO ResultF
readItemFileIDs Index
index forall a b. (a -> b) -> a -> b
$ State
substate {start :: Int
start = Int
off}
                  [(Maybe Name, ResultF)]
rest <- Int -> IO [(Maybe Name, ResultF)]
subs forall a b. (a -> b) -> a -> b
$ ResultF -> Int
nextF ResultF
result
                  forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$! (Item -> State -> Maybe Name
nameof (ResultF -> Item
resitemF ResultF
result) State
substate, ResultF
result) forall a. a -> [a] -> [a]
: [(Maybe Name, ResultF)]
rest
                Ordering
EQ -> forall (m :: * -> *) a. Monad m => a -> m a
return []
                Ordering
GT ->
                  forall (m :: * -> *) a. MonadFail m => String -> m a
fail forall a b. (a -> b) -> a -> b
$
                    String
"Offset mismatch at " forall a. [a] -> [a] -> [a]
++ forall a. Show a => a -> String
show Int
off forall a. [a] -> [a] -> [a]
++
                    String
" (ends at " forall a. [a] -> [a] -> [a]
++ forall a. Show a => a -> String
show Int
following forall a. [a] -> [a] -> [a]
++ String
")"
       [(Maybe Name, ResultF)]
inferiors <- Int -> IO [(Maybe Name, ResultF)]
subs forall a b. (a -> b) -> a -> b
$ State -> Int
start State
substate
       forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ ResultF { nextF :: Int
nextF = Int
following
                        , resitemF :: Item
resitemF = Item
item
                        , _fileIDs :: [((AnchoredPath, ItemType), FileID)]
_fileIDs = (((State -> AnchoredPath
path State
substate, ItemType
TreeType), FileID
fileid)forall a. a -> [a] -> [a]
:forall (t :: * -> *) a b. Foldable t => (a -> [b]) -> t a -> [b]
concatMap (ResultF -> [((AnchoredPath, ItemType), FileID)]
_fileIDs forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall a b. (a, b) -> b
snd) [(Maybe Name, ResultF)]
inferiors) }

readFileFileID :: Index -> State -> Item -> IO ResultF
readFileFileID :: Index -> State -> Item -> IO ResultF
readFileFileID Index
_ State
state Item
item =
    do FileID
fileid' <- forall a b. (Integral a, Num b) => a -> b
fromIntegral forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> (forall a. Storable a => Ptr a -> IO a
peek forall a b. (a -> b) -> a -> b
$ Item -> Ptr FileID
iFileID Item
item)
       let myname :: Maybe Name
myname = Item -> State -> Maybe Name
nameof Item
item State
state
       forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ ResultF { nextF :: Int
nextF = State -> Int
start State
state forall a. Num a => a -> a -> a
+ Item -> Int
itemNext Item
item
                        , resitemF :: Item
resitemF = Item
item
                        , _fileIDs :: [((AnchoredPath, ItemType), FileID)]
_fileIDs = [((State -> AnchoredPath
path State
state AnchoredPath -> Maybe Name -> AnchoredPath
`maybeAppendName` Maybe Name
myname, ItemType
BlobType), FileID
fileid')] }

-- * Reading and writing 'Tree's from/to the index

-- | Read an index and build up a 'Tree' object from it, referring to current
-- working directory. The initial Index object returned by openIndex is not
-- directly useful. However, you can use 'Tree.filter' on it. Either way, to
-- obtain the actual Tree object, call update.
--
-- The usual use pattern is this:
--
-- > do (idx, update) <- openIndex
-- >    tree <- update =<< filter predicate idx
--
-- The resulting tree will be fully expanded.
openIndex :: FilePath -> (Tree IO -> Hash) -> IO Index
openIndex :: String -> (Tree IO -> Hash) -> IO Index
openIndex String
indexpath Tree IO -> Hash
ht = do
  (ForeignPtr ()
mmap_ptr, Int
mmap_size) <- forall a. String -> Int -> IO (ForeignPtr a, Int)
mmapIndex String
indexpath Int
0
  String
base <- IO String
getCurrentDirectory
  forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ if Int
mmap_size forall a. Eq a => a -> a -> Bool
== Int
0 then forall (m :: * -> *). IndexM m
EmptyIndex
                             else Index { mmap :: ForeignPtr ()
mmap = ForeignPtr ()
mmap_ptr
                                        , basedir :: String
basedir = String
base
                                        , hashtree :: Tree IO -> Hash
hashtree = Tree IO -> Hash
ht
                                        , predicate :: AnchoredPath -> TreeItem IO -> Bool
predicate = \AnchoredPath
_ TreeItem IO
_ -> Bool
True }

formatIndex :: ForeignPtr () -> Tree IO -> Tree IO -> IO ()
formatIndex :: ForeignPtr () -> Tree IO -> Tree IO -> IO ()
formatIndex ForeignPtr ()
mmap_ptr Tree IO
old Tree IO
reference =
    do Int
_ <- forall {m :: * -> *}. TreeItem m -> AnchoredPath -> Int -> IO Int
create (forall (m :: * -> *). Tree m -> TreeItem m
SubTree Tree IO
reference) (AnchoredPath
anchoredRoot) Int
size_header
       ByteString -> ByteString -> IO ()
unsafePokeBS ByteString
magic ByteString
index_version
       forall a b. ForeignPtr a -> (Ptr a -> IO b) -> IO b
withForeignPtr ForeignPtr ()
mmap_ptr forall a b. (a -> b) -> a -> b
$ \Ptr ()
ptr ->
         forall a b. Storable a => Ptr b -> Int -> a -> IO ()
pokeByteOff Ptr ()
ptr Int
size_magic Int32
index_endianness_indicator
    where magic :: ByteString
magic = ForeignPtr Word8 -> Int -> Int -> ByteString
fromForeignPtr (forall a b. ForeignPtr a -> ForeignPtr b
castForeignPtr ForeignPtr ()
mmap_ptr) Int
0 Int
4
          create :: TreeItem m -> AnchoredPath -> Int -> IO Int
create (File Blob m
_) AnchoredPath
path' Int
off =
               do Item
i <- ItemType -> AnchoredPath -> ForeignPtr () -> Int -> IO Item
createItem ItemType
BlobType AnchoredPath
path' ForeignPtr ()
mmap_ptr Int
off
                  let flatpath :: String
flatpath = String -> AnchoredPath -> String
anchorPath String
"" AnchoredPath
path'
                  case forall (m :: * -> *). Tree m -> AnchoredPath -> Maybe (TreeItem m)
find Tree IO
old AnchoredPath
path' of
                    Maybe (TreeItem IO)
Nothing -> forall (m :: * -> *) a. Monad m => a -> m a
return ()
                    -- TODO calling getFileStatus here is both slightly
                    -- inefficient and slightly race-prone
                    Just TreeItem IO
ti -> do FileStatus
st <- String -> IO FileStatus
getFileStatus String
flatpath
                                  let hash :: Hash
hash = forall (m :: * -> *). TreeItem m -> Hash
itemHash TreeItem IO
ti
                                      mtime :: EpochTime
mtime = FileStatus -> EpochTime
modificationTime FileStatus
st
                                      size :: FileOffset
size = FileStatus -> FileOffset
fileSize FileStatus
st
                                  Item -> Int64 -> Hash -> IO ()
updateItem Item
i (forall a b. (Integral a, Num b) => a -> b
fromIntegral FileOffset
size) Hash
hash
                                  forall a. Enum a => Item -> a -> IO ()
updateTime Item
i EpochTime
mtime
                  forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ Int
off forall a. Num a => a -> a -> a
+ Item -> Int
itemNext Item
i
          create (SubTree Tree m
s) AnchoredPath
path' Int
off =
               do Item
i <- ItemType -> AnchoredPath -> ForeignPtr () -> Int -> IO Item
createItem ItemType
TreeType AnchoredPath
path' ForeignPtr ()
mmap_ptr Int
off
                  case forall (m :: * -> *). Tree m -> AnchoredPath -> Maybe (TreeItem m)
find Tree IO
old AnchoredPath
path' of
                    Maybe (TreeItem IO)
Nothing -> forall (m :: * -> *) a. Monad m => a -> m a
return ()
                    Just TreeItem IO
ti | forall (m :: * -> *). TreeItem m -> Hash
itemHash TreeItem IO
ti forall a. Eq a => a -> a -> Bool
== Hash
NoHash -> forall (m :: * -> *) a. Monad m => a -> m a
return ()
                            | Bool
otherwise -> Item -> Int64 -> Hash -> IO ()
updateItem Item
i Int64
0 forall a b. (a -> b) -> a -> b
$ forall (m :: * -> *). TreeItem m -> Hash
itemHash TreeItem IO
ti
                  let subs :: [(Name, TreeItem m)] -> IO Int
subs [] = forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ Int
off forall a. Num a => a -> a -> a
+ Item -> Int
itemNext Item
i
                      subs ((Name
name,TreeItem m
x):[(Name, TreeItem m)]
xs) = do
                        let path'' :: AnchoredPath
path'' = AnchoredPath
path' AnchoredPath -> Name -> AnchoredPath
`appendPath` Name
name
                        Int
noff <- [(Name, TreeItem m)] -> IO Int
subs [(Name, TreeItem m)]
xs
                        TreeItem m -> AnchoredPath -> Int -> IO Int
create TreeItem m
x AnchoredPath
path'' Int
noff
                  Int
lastOff <- [(Name, TreeItem m)] -> IO Int
subs (forall (m :: * -> *). Tree m -> [(Name, TreeItem m)]
listImmediate Tree m
s)
                  forall a. Storable a => Ptr a -> a -> IO ()
poke (Item -> Ptr Int64
iAux Item
i) (forall a b. (Integral a, Num b) => a -> b
fromIntegral Int
lastOff)
                  forall (m :: * -> *) a. Monad m => a -> m a
return Int
lastOff
          create (Stub m (Tree m)
_ Hash
_) AnchoredPath
path' Int
_ =
               forall (m :: * -> *) a. MonadFail m => String -> m a
fail forall a b. (a -> b) -> a -> b
$ String
"Cannot create index from stubbed Tree at " forall a. [a] -> [a] -> [a]
++ forall a. Show a => a -> String
show AnchoredPath
path'

-- | Will add and remove files in index to make it match the 'Tree' object
-- given (it is an error for the 'Tree' to contain a file or directory that
-- does not exist in a plain form in current working directory).
updateIndexFrom :: FilePath -> (Tree IO -> Hash) -> Tree IO -> IO Index
updateIndexFrom :: String -> (Tree IO -> Hash) -> Tree IO -> IO Index
updateIndexFrom String
indexpath Tree IO -> Hash
hashtree' Tree IO
ref =
    do Tree IO
old_tree <- Index -> IO (Tree IO)
treeFromIndex forall (m :: * -> *) a b. Monad m => (a -> m b) -> m a -> m b
=<< String -> (Tree IO -> Hash) -> IO Index
openIndex String
indexpath Tree IO -> Hash
hashtree'
       Tree IO
reference <- forall (m :: * -> *). Monad m => Tree m -> m (Tree m)
expand Tree IO
ref
       let len_root :: Int
len_root = AnchoredPath -> Int
itemAllocSize AnchoredPath
anchoredRoot
           len :: Int
len = Int
len_root forall a. Num a => a -> a -> a
+ forall (t :: * -> *) a. (Foldable t, Num a) => t a -> a
sum [ AnchoredPath -> Int
itemAllocSize AnchoredPath
p | (AnchoredPath
p, TreeItem IO
_) <- forall (m :: * -> *). Tree m -> [(AnchoredPath, TreeItem m)]
list Tree IO
reference ]
       Bool
exist <- String -> IO Bool
doesFileExist String
indexpath
       -- Note that the file is still open via the mmaped pointer in
       -- the open index, and we /are/ going to write the index using
       -- that pointer. If we could rely on posix semantics,
       -- we would just delete the file. However, on windows this
       -- would fail, so instead we rename it.
       forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when Bool
exist forall a b. (a -> b) -> a -> b
$ String -> String -> IO ()
renameFile String
indexpath (String
indexpath String -> ShowS
<.> String
"old")
       (ForeignPtr ()
mmap_ptr, Int
_) <- forall a. String -> Int -> IO (ForeignPtr a, Int)
mmapIndex String
indexpath Int
len
       ForeignPtr () -> Tree IO -> Tree IO -> IO ()
formatIndex ForeignPtr ()
mmap_ptr Tree IO
old_tree Tree IO
reference
       String -> (Tree IO -> Hash) -> IO Index
openIndex String
indexpath Tree IO -> Hash
hashtree'

-- | Read the index, starting with the root, to create a 'Tree'.
treeFromIndex :: Index -> IO (Tree IO)
treeFromIndex :: Index -> IO (Tree IO)
treeFromIndex Index
EmptyIndex = forall (m :: * -> *) a. Monad m => a -> m a
return forall (m :: * -> *). Tree m
emptyTree
treeFromIndex Index
index =
    do let initial :: State
initial = State { start :: Int
start = Int
size_header
                           , dirlength :: Int
dirlength = Int
0
                           , path :: AnchoredPath
path = AnchoredPath
anchoredRoot }
       Result
res <- Index -> State -> IO Result
readItem Index
index State
initial
       case Result -> Maybe (TreeItem IO)
treeitem Result
res of
         Just (SubTree Tree IO
tree) -> forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ forall (a :: (* -> *) -> *) (m :: * -> *).
FilterTree a m =>
(AnchoredPath -> TreeItem m -> Bool) -> a m -> a m
filter (forall (m :: * -> *).
IndexM m -> AnchoredPath -> TreeItem m -> Bool
predicate Index
index) Tree IO
tree
         Maybe (TreeItem IO)
_ -> forall (m :: * -> *) a. MonadFail m => String -> m a
fail String
"Unexpected failure in treeFromIndex!"

-- | Check that a given file is an index file with a format we can handle. You
-- should remove and re-create the index whenever this is not true.
indexFormatValid :: FilePath -> IO Bool
indexFormatValid :: String -> IO Bool
indexFormatValid String
path' =
  do
    (ForeignPtr Any
start, Int
_, Int
_) <- forall a.
String -> Mode -> Maybe (Int64, Int) -> IO (ForeignPtr a, Int, Int)
mmapFileForeignPtr String
path' Mode
ReadOnly (forall a. a -> Maybe a
Just (Int64
0, Int
size_header))
    let magic :: ByteString
magic = ForeignPtr Word8 -> Int -> Int -> ByteString
fromForeignPtr (forall a b. ForeignPtr a -> ForeignPtr b
castForeignPtr ForeignPtr Any
start) Int
0 Int
4
    Int32
endianness_indicator <- forall a b. ForeignPtr a -> (Ptr a -> IO b) -> IO b
withForeignPtr ForeignPtr Any
start forall a b. (a -> b) -> a -> b
$ \Ptr Any
ptr -> forall a b. Storable a => Ptr b -> Int -> IO a
peekByteOff Ptr Any
ptr Int
4
    forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$
      ByteString
index_version forall a. Eq a => a -> a -> Bool
== ByteString
magic Bool -> Bool -> Bool
&& Int32
index_endianness_indicator forall a. Eq a => a -> a -> Bool
== Int32
endianness_indicator
  forall e a. Exception e => IO a -> (e -> IO a) -> IO a
`catch` \(SomeException
_::SomeException) -> forall (m :: * -> *) a. Monad m => a -> m a
return Bool
False

instance FilterTree IndexM IO where
    filter :: (AnchoredPath -> TreeItem IO -> Bool) -> Index -> Index
filter AnchoredPath -> TreeItem IO -> Bool
_ Index
EmptyIndex = forall (m :: * -> *). IndexM m
EmptyIndex
    filter AnchoredPath -> TreeItem IO -> Bool
p Index
index = Index
index { predicate :: AnchoredPath -> TreeItem IO -> Bool
predicate = \AnchoredPath
a TreeItem IO
b -> forall (m :: * -> *).
IndexM m -> AnchoredPath -> TreeItem m -> Bool
predicate Index
index AnchoredPath
a TreeItem IO
b Bool -> Bool -> Bool
&& AnchoredPath -> TreeItem IO -> Bool
p AnchoredPath
a TreeItem IO
b }


-- * Getting the file ID from a path

-- | For a given file or folder path, get the corresponding fileID from the
-- filesystem.
getFileID :: AnchoredPath -> IO (Maybe FileID)
getFileID :: AnchoredPath -> IO (Maybe FileID)
getFileID = String -> IO (Maybe FileID)
getFileID' forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> AnchoredPath -> String
anchorPath String
""

getFileID' :: FilePath -> IO (Maybe FileID)
getFileID' :: String -> IO (Maybe FileID)
getFileID' String
fp = do
  Bool
file_exists <- String -> IO Bool
doesFileExist String
fp
  Bool
dir_exists <- String -> IO Bool
doesDirectoryExist String
fp
  if Bool
file_exists Bool -> Bool -> Bool
|| Bool
dir_exists
#ifdef WIN32
    then do
      h <-
        createFile fp gENERIC_NONE fILE_SHARE_NONE Nothing
        oPEN_EXISTING fILE_FLAG_BACKUP_SEMANTICS Nothing
      fhnumber <-
        (Just . fromIntegral . bhfiFileIndex) <$> getFileInformationByHandle h
      closeHandle h
      return fhnumber
#else
    then (forall a. a -> Maybe a
Just forall b c a. (b -> c) -> (a -> b) -> a -> c
. FileStatus -> FileID
F.fileID) forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> String -> IO FileStatus
F.getSymbolicLinkStatus String
fp
#endif
    else forall (m :: * -> *) a. Monad m => a -> m a
return forall a. Maybe a
Nothing


-- * Low-level utilities

-- Wow, unsafe.
unsafePokeBS :: BC.ByteString -> BC.ByteString -> IO ()
unsafePokeBS :: ByteString -> ByteString -> IO ()
unsafePokeBS ByteString
to ByteString
from =
    do let (ForeignPtr Word8
fp_to, Int
off_to, Int
len_to) = ByteString -> (ForeignPtr Word8, Int, Int)
toForeignPtr ByteString
to
           (ForeignPtr Word8
fp_from, Int
off_from, Int
len_from) = ByteString -> (ForeignPtr Word8, Int, Int)
toForeignPtr ByteString
from
       forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when (Int
len_to forall a. Eq a => a -> a -> Bool
/= Int
len_from) forall a b. (a -> b) -> a -> b
$ forall (m :: * -> *) a. MonadFail m => String -> m a
fail forall a b. (a -> b) -> a -> b
$ String
"Length mismatch in unsafePokeBS: from = "
            forall a. [a] -> [a] -> [a]
++ forall a. Show a => a -> String
show Int
len_from forall a. [a] -> [a] -> [a]
++ String
" /= to = " forall a. [a] -> [a] -> [a]
++ forall a. Show a => a -> String
show Int
len_to
       forall a b. ForeignPtr a -> (Ptr a -> IO b) -> IO b
withForeignPtr ForeignPtr Word8
fp_from forall a b. (a -> b) -> a -> b
$ \Ptr Word8
p_from ->
         forall a b. ForeignPtr a -> (Ptr a -> IO b) -> IO b
withForeignPtr ForeignPtr Word8
fp_to forall a b. (a -> b) -> a -> b
$ \Ptr Word8
p_to ->
           Ptr Word8 -> Ptr Word8 -> Int -> IO ()
memcpy (forall a b. Ptr a -> Int -> Ptr b
plusPtr Ptr Word8
p_to Int
off_to)
                  (forall a b. Ptr a -> Int -> Ptr b
plusPtr Ptr Word8
p_from Int
off_from)
                  (forall a b. (Integral a, Num b) => a -> b
fromIntegral Int
len_to)

align :: Integral a => a -> a -> a
align :: forall a. Integral a => a -> a -> a
align a
boundary a
i = case a
i forall a. Integral a => a -> a -> a
`rem` a
boundary of
                     a
0 -> a
i
                     a
x -> a
i forall a. Num a => a -> a -> a
+ a
boundary forall a. Num a => a -> a -> a
- a
x
{-# INLINE align #-}

getFileStatus :: FilePath -> IO FileStatus
getFileStatus :: String -> IO FileStatus
getFileStatus String
path = do
  FileStatus
mst <- String -> IO FileStatus
Darcs.Util.File.getFileStatus String
path
  case FileStatus
mst of
    Just FileStatus
st
      | FileStatus -> Bool
F.isSymbolicLink FileStatus
st -> do
          Handle -> String -> IO ()
hPutStrLn Handle
stderr forall a b. (a -> b) -> a -> b
$ String
"Warning: ignoring symbolic link " forall a. [a] -> [a] -> [a]
++ String
path
          forall (m :: * -> *) a. Monad m => a -> m a
return forall a. Maybe a
Nothing
    FileStatus
_ -> forall (m :: * -> *) a. Monad m => a -> m a
return FileStatus
mst