System.Directory.OsPath.Streaming

You’ll most likely be interested in either

• getDirectoryContentsRecursive to search directory hierarchy recursively
• DirStream, openDirStream, readDirStream, and closeDirStream to traverse single directory efficiently

Documentation

data DirStream

Abstract handle to directory contents.

May be closed multiple times and will be automatically closed by GC when it goes out of scope.

openDirStream :: OsPath -> IO DirStream

readDirStream :: DirStream -> IO (Maybe (OsPath, FileType))

closeDirStream :: DirStream -> IO ()

Deallocate directory handle. It’s safe to close DirStream multiple times, unlike the underlying OS-specific directory stream handle.

File types

data SymlinkType

Constructors

Regular

Symlink

Instances

Generic SymlinkType

Defined in System.Directory.OsPath.Types

Associated Types

type Rep SymlinkType :: Type -> Type

Methods

from :: SymlinkType -> Rep SymlinkType x

to :: Rep SymlinkType x -> SymlinkType

Read SymlinkType

Defined in System.Directory.OsPath.Types

Methods

readsPrec :: Int -> ReadS SymlinkType

readList :: ReadS [SymlinkType]

readPrec :: ReadPrec SymlinkType

readListPrec :: ReadPrec [SymlinkType]

Show SymlinkType

Defined in System.Directory.OsPath.Types

Methods

showsPrec :: Int -> SymlinkType -> ShowS

show :: SymlinkType -> String

showList :: [SymlinkType] -> ShowS

NFData SymlinkType

Defined in System.Directory.OsPath.Types

Methods

rnf :: SymlinkType -> ()

Eq SymlinkType

Defined in System.Directory.OsPath.Types

Methods

(==) :: SymlinkType -> SymlinkType -> Bool

(/=) :: SymlinkType -> SymlinkType -> Bool

Ord SymlinkType

Defined in System.Directory.OsPath.Types

Methods

compare :: SymlinkType -> SymlinkType -> Ordering

(<) :: SymlinkType -> SymlinkType -> Bool

(<=) :: SymlinkType -> SymlinkType -> Bool

(>) :: SymlinkType -> SymlinkType -> Bool

(>=) :: SymlinkType -> SymlinkType -> Bool

max :: SymlinkType -> SymlinkType -> SymlinkType

min :: SymlinkType -> SymlinkType -> SymlinkType

type Rep SymlinkType

Defined in System.Directory.OsPath.Types

type Rep SymlinkType = D1 ('MetaData "SymlinkType" "System.Directory.OsPath.Types" "directory-ospath-streaming-0.2-7RVORjIhdhMHkPO5xAl8fN" 'False) (C1 ('MetaCons "Regular" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "Symlink" 'PrefixI 'False) (U1 :: Type -> Type))

data FileType

Constructors

File !SymlinkType

Directory !SymlinkType

Other !SymlinkType

Instances

Generic FileType

Defined in System.Directory.OsPath.Types

Associated Types

type Rep FileType :: Type -> Type

Methods

from :: FileType -> Rep FileType x

to :: Rep FileType x -> FileType

Read FileType

Defined in System.Directory.OsPath.Types

Methods

readsPrec :: Int -> ReadS FileType

readList :: ReadS [FileType]

readPrec :: ReadPrec FileType

readListPrec :: ReadPrec [FileType]

Show FileType

Defined in System.Directory.OsPath.Types

Methods

showsPrec :: Int -> FileType -> ShowS

show :: FileType -> String

showList :: [FileType] -> ShowS

NFData FileType

Defined in System.Directory.OsPath.Types

Methods

rnf :: FileType -> ()

Eq FileType

Defined in System.Directory.OsPath.Types

Methods

(==) :: FileType -> FileType -> Bool

(/=) :: FileType -> FileType -> Bool

Ord FileType

Defined in System.Directory.OsPath.Types

Methods

compare :: FileType -> FileType -> Ordering

(<) :: FileType -> FileType -> Bool

(<=) :: FileType -> FileType -> Bool

(>) :: FileType -> FileType -> Bool

(>=) :: FileType -> FileType -> Bool

max :: FileType -> FileType -> FileType

min :: FileType -> FileType -> FileType

type Rep FileType

Defined in System.Directory.OsPath.Types

type Rep FileType = D1 ('MetaData "FileType" "System.Directory.OsPath.Types" "directory-ospath-streaming-0.2-7RVORjIhdhMHkPO5xAl8fN" 'False) (C1 ('MetaCons "File" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'SourceUnpack 'SourceStrict 'DecidedStrict) (Rec0 SymlinkType)) :+: (C1 ('MetaCons "Directory" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'SourceUnpack 'SourceStrict 'DecidedStrict) (Rec0 SymlinkType)) :+: C1 ('MetaCons "Other" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'SourceUnpack 'SourceStrict 'DecidedStrict) (Rec0 SymlinkType))))

newtype Basename a

Basename part of filename, without directory separators.

Constructors

Basename

Fields

• unBasename :: a

Instances

Foldable Basename

Defined in System.Directory.OsPath.Types

Methods

fold :: Monoid m => Basename m -> m

foldMap :: Monoid m => (a -> m) -> Basename a -> m

foldMap' :: Monoid m => (a -> m) -> Basename a -> m

foldr :: (a -> b -> b) -> b -> Basename a -> b

foldr' :: (a -> b -> b) -> b -> Basename a -> b

foldl :: (b -> a -> b) -> b -> Basename a -> b

foldl' :: (b -> a -> b) -> b -> Basename a -> b

foldr1 :: (a -> a -> a) -> Basename a -> a

foldl1 :: (a -> a -> a) -> Basename a -> a

toList :: Basename a -> [a]

null :: Basename a -> Bool

length :: Basename a -> Int

elem :: Eq a => a -> Basename a -> Bool

maximum :: Ord a => Basename a -> a

minimum :: Ord a => Basename a -> a

sum :: Num a => Basename a -> a

product :: Num a => Basename a -> a

Traversable Basename

Defined in System.Directory.OsPath.Types

Methods

traverse :: Applicative f => (a -> f b) -> Basename a -> f (Basename b)

sequenceA :: Applicative f => Basename (f a) -> f (Basename a)

mapM :: Monad m => (a -> m b) -> Basename a -> m (Basename b)

sequence :: Monad m => Basename (m a) -> m (Basename a)

Functor Basename

Defined in System.Directory.OsPath.Types

Methods

fmap :: (a -> b) -> Basename a -> Basename b

(<$) :: a -> Basename b -> Basename a

Generic1 Basename

Defined in System.Directory.OsPath.Types

Associated Types

type Rep1 Basename :: k -> Type

Methods

from1 :: forall (a :: k). Basename a -> Rep1 Basename a

to1 :: forall (a :: k). Rep1 Basename a -> Basename a

Generic (Basename a)

Defined in System.Directory.OsPath.Types

Associated Types

type Rep (Basename a) :: Type -> Type

Methods

from :: Basename a -> Rep (Basename a) x

to :: Rep (Basename a) x -> Basename a

Show a => Show (Basename a)

Defined in System.Directory.OsPath.Types

Methods

showsPrec :: Int -> Basename a -> ShowS

show :: Basename a -> String

showList :: [Basename a] -> ShowS

NFData a => NFData (Basename a)

Defined in System.Directory.OsPath.Types

Methods

rnf :: Basename a -> ()

Eq a => Eq (Basename a)

Defined in System.Directory.OsPath.Types

Methods

(==) :: Basename a -> Basename a -> Bool

(/=) :: Basename a -> Basename a -> Bool

Ord a => Ord (Basename a)

Defined in System.Directory.OsPath.Types

Methods

compare :: Basename a -> Basename a -> Ordering

(<) :: Basename a -> Basename a -> Bool

(<=) :: Basename a -> Basename a -> Bool

(>) :: Basename a -> Basename a -> Bool

(>=) :: Basename a -> Basename a -> Bool

max :: Basename a -> Basename a -> Basename a

min :: Basename a -> Basename a -> Basename a

type Rep1 Basename

Defined in System.Directory.OsPath.Types

type Rep1 Basename = D1 ('MetaData "Basename" "System.Directory.OsPath.Types" "directory-ospath-streaming-0.2-7RVORjIhdhMHkPO5xAl8fN" 'True) (C1 ('MetaCons "Basename" 'PrefixI 'True) (S1 ('MetaSel ('Just "unBasename") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) Par1))

type Rep (Basename a)

Defined in System.Directory.OsPath.Types

type Rep (Basename a) = D1 ('MetaData "Basename" "System.Directory.OsPath.Types" "directory-ospath-streaming-0.2-7RVORjIhdhMHkPO5xAl8fN" 'True) (C1 ('MetaCons "Basename" 'PrefixI 'True) (S1 ('MetaSel ('Just "unBasename") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 a)))

getFileType :: OsPath -> IO FileType

Get directory contents

getDirectoryContentsRecursive :: OsPath -> IO [(OsPath, FileType)]

Recursively list all the files and directories in a directory and all subdirectories.

The directory structure is traversed depth-first.

The result is generated lazily so is not well defined if the source directory structure changes before the list is fully consumed.

Symlinks within directory structure may cause result to be infinitely long.

listContentsRecFold

Arguments

:: forall f a b. (Foldable f, Coercible b OsPath)

=> Maybe Int

Depth limit if specified, negative values treated the same as positive ones.

-> (forall c. OsPath -> b -> Relative OsPath -> Basename OsPath -> SymlinkType -> (a -> IO c -> IO c) -> (IO c -> IO c) -> IO c -> IO c)

Decide how to fold directory and its children given its path.

Can do IO actions to plan what to do and typically should derive its result from last IO c argument.

Returns IO c where c is hidden from the user so the only way to make it is to construct from the passed IO c action.

Arguments:

• OsPath - absolute path to the visited directory
• b - root of the visited directory as passed originally in f b to the bigger fold function
• Relative OsPath - path to the visited directory relative to the previous b argument
• Basename OsPath - name of the visited directory without slashes
• SymlinkType - symlink status of the visited directory
• (a -> IO c -> IO c) - can be used to record some output (a) about the directory itself
• (IO c -> IO c) - traverse inside this directory, can be ignored to skip its children
• IO c - continue scanning not yet visited parts, must be used to construct return value (otherwise it won’t typecheck!)

The passed (IO c -> IO c) argument function should (but is not required to) be applied in the returned function and it will prepend results for subdirectories of the directory being analyzed. If not applied these subdirectories will be skipped, this way ignoring particular directory and all its children can be achieved.

-> (OsPath -> b -> Relative OsPath -> Basename OsPath -> FileType -> IO (Maybe a))

What to do with file

-> f b

Roots to search in, either absolute or relative

-> IO [a]

The most general form of gathering directory contents.

Treats symlinks the same as regular files and directories. Folding functions can decide how to handle symlinks.

Both directory and file actions can throw exceptions and this function will try to close finished directory streams promptly (they’ll be closed by GC in the worst case).

Utilities

regularFile :: FileType

Auxiliary constants to refer to different file types without allocations.

regularDirectory :: FileType

Auxiliary constants to refer to different file types without allocations.

regularOther :: FileType

Auxiliary constants to refer to different file types without allocations.

symlinkFile :: FileType

Auxiliary constants to refer to different file types without allocations.

symlinkDirectory :: FileType

Auxiliary constants to refer to different file types without allocations.

symlinkOther :: FileType

Auxiliary constants to refer to different file types without allocations.