Moduledirectory-ospath-streaming-0.3Haskell2010

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

4 types
14 values

Packagedirectory-ospath-streaming-0.3
Exports18
LanguageHaskell2010
LicenceApache-2.0
SourceStreaming.hs

datadata DirStream

Abstract handle to directory contents.

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

valueopenDirStream :: OsPath -> IO DirStream

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

Returns basename path of the directory entry.

valuereadDirStreamFull

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

Returns both basename path and full path of a directory entry relative to the passed DirStream root.

For example:

readDirStreamFull =<< openDirStream [osp|.|]
Just ("./bar",Basename {unBasename = "foo"},File Regular)

readDirStreamFull =<< openDirStream [osp|foo/|]
Just ("foo/bar",Basename {unBasename = "foo"},File Regular)

readDirStreamFull =<< openDirStream [osp|/foo/foo|]
Just ("/foo/foo/bar",Basename {unBasename = "foo"},File Regular)

This allows to avoid re-creating the full path on the client side and thus reduce allocations.

valuecloseDirStream :: DirStream -> IO ()

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

File types

4 declarations

datadata SymlinkType

Regular Symlink

Instances7Eq, Ord, Read, Show, Generic, NFData, …

Eq SymlinkTypeDefined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types
Ord SymlinkTypeDefined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types
Read SymlinkTypeDefined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types
Show SymlinkTypeDefined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types
Generic SymlinkTypeDefined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types
NFData SymlinkTypeDefined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types
type Rep SymlinkType = D1 ('MetaData "SymlinkType" "System.Directory.OsPath.Types" "directory-ospath-streaming-0.3-3854tZliPMYHB0V0eRQx2X" 'False) (C1 ('MetaCons "Regular" 'PrefixI 'False) U1 :+: C1 ('MetaCons "Symlink" 'PrefixI 'False) U1)Defined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types

datadata FileType

Constructors

Instances7Eq, Ord, Read, Show, Generic, NFData, …

Eq FileTypeDefined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types
Ord FileTypeDefined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types
Read FileTypeDefined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types
Show FileTypeDefined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types
Generic FileTypeDefined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types
NFData FileTypeDefined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types
type Rep FileType = D1 ('MetaData "FileType" "System.Directory.OsPath.Types" "directory-ospath-streaming-0.3-3854tZliPMYHB0V0eRQx2X" 'False) (C1 ('MetaCons "File" 'PrefixI 'False) (S1 ('MetaSel 'Nothing 'SourceUnpack 'SourceStrict 'DecidedUnpack) (Rec0 SymlinkType)) :+: (C1 ('MetaCons "Directory" 'PrefixI 'False) (S1 ('MetaSel 'Nothing 'SourceUnpack 'SourceStrict 'DecidedUnpack) (Rec0 SymlinkType)) :+: C1 ('MetaCons "Other" 'PrefixI 'False) (S1 ('MetaSel 'Nothing 'SourceUnpack 'SourceStrict 'DecidedUnpack) (Rec0 SymlinkType))))Defined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types

newtypenewtype Basename a

Basename part of filename, without directory separators.

Constructors

Basename
- unBasename :: a

Instances11Functor, Foldable, Traversable, Generic1, Eq, Ord, …

Functor BasenameDefined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types
Foldable BasenameDefined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types
Traversable BasenameDefined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types
Generic1 BasenameDefined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types
Eq a => Eq (Basename a)Defined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types
Ord a => Ord (Basename a)Defined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types
Show a => Show (Basename a)Defined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types
Generic (Basename a)Defined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types
NFData a => NFData (Basename a)Defined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types
type Rep (Basename a) = D1 ('MetaData "Basename" "System.Directory.OsPath.Types" "directory-ospath-streaming-0.3-3854tZliPMYHB0V0eRQx2X" 'True) (C1 ('MetaCons "Basename" 'PrefixI 'True) (S1 ('MetaSel ('Just "unBasename") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 a)))Defined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types
type Rep1 Basename = D1 ('MetaData "Basename" "System.Directory.OsPath.Types" "directory-ospath-streaming-0.3-3854tZliPMYHB0V0eRQx2X" 'True) (C1 ('MetaCons "Basename" 'PrefixI 'True) (S1 ('MetaSel ('Just "unBasename") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) Par1))Defined in directory-ospath-streaming-0.3 · System.Directory.OsPath.Types

valuegetFileType :: OsPath -> IO FileType

Get directory contents

3 declarations

valuegetDirectoryContentsRecursive :: 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.

valuegetDirectoryContentsWithFilterRecursive

:: (Basename OsPath -> SymlinkType -> Bool)
Whether to visit a directory
-> (Basename OsPath -> Bool)
Whether to collect given directory element, either file or directory.
-> OsPath
-> IO [(OsPath, FileType)]

Recursively list all the files and directories that satisfy given predicate in a directory and all subdirectories. Descending into some subdirectories may be avoided by filtering them out with a visiting predicate.

Not visited directory entry may still be reported depending on the collection predicate.

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, but they can be filtered out with a suitable directory visiting predicate.

valuelistContentsRecFold

:: (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 - full path to the visited directory relative to root we’re searching in. If the root was absolute then this path would be too, if it was relative then this path would be relative to the same target.
- 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).