Documentation

Fields

• dumpState :: m String

  Debugging: human-readable description of file system state

• hOpen :: HasCallStack => FsPath -> OpenMode -> m (Handle h)

  Open a file

• hClose :: HasCallStack => Handle h -> m ()

  Close a file

• hIsOpen :: HasCallStack => Handle h -> m Bool

  Is the handle open?

• hSeek :: HasCallStack => Handle h -> SeekMode -> Int64 -> m ()

  Seek handle

  The offset is an Int64 rather than a Word64 because it may be negative (for use in relative positioning).

  Unlike the Posix lseek, hSeek does not return the new seek position because the value returned by Posix is rather strange and unreliable and we don't want to emulate it's behaviour.

• hGetSome :: HasCallStack => Handle h -> Word64 -> m ByteString

  Try to read n bytes from a handle

  When at the end of the file, an empty bytestring will be returned.

  The returned bytestring will typically have length n, but may be shorter in case of a partial read, see #277. However, a partial read will always return at least 1 byte, as returning 0 bytes would mean that we have reached EOF.

  Postcondition: the length of the returned bytestring @n@ and= 0.

• hGetSomeAt :: HasCallStack => Handle h -> Word64 -> AbsOffset -> m ByteString

  Same as hGetSome, but does not affect the file offset. An additional argument is used to specify the offset. This allows it to be called concurrently for the same file handle. However, the actual level of parallelism achieved depends on the implementation and the operating system: generally on Unix it will be "more parallel" than on Windows.

• hPutSome :: HasCallStack => Handle h -> ByteString -> m Word64

  Write to a handle

  The return value indicates the number of bytes written and will typically be equal to l, the length of the bytestring, but may be shorter in case of a partial write, see #277.

  If nothing can be written at all, an exception will be thrown.

  Postcondition: the return value @l@ and 0, unless the given bytestring is empty, in which case the return value can be 0.

• hTruncate :: HasCallStack => Handle h -> Word64 -> m ()

  Truncate the file to the specified size

  NOTE: Only supported in append mode.

• hGetSize :: HasCallStack => Handle h -> m Word64

  Return current file size

  NOTE: This is not thread safe (changes made to the file in other threads may affect this thread).

• createDirectory :: HasCallStack => FsPath -> m ()

  Create new directory

• createDirectoryIfMissing :: HasCallStack => Bool -> FsPath -> m ()

  Create new directory if it doesn't exist.

  createDirectoryIfMissing True will also try to create all parent dirs.

• listDirectory :: HasCallStack => FsPath -> m (Set String)

  List contents of a directory

• doesDirectoryExist :: HasCallStack => FsPath -> m Bool

  Check if the path exists and is a directory

• doesFileExist :: HasCallStack => FsPath -> m Bool

  Check if the path exists and is a file

• removeFile :: HasCallStack => FsPath -> m ()

  Remove the file (which must exist)

• renameFile :: HasCallStack => FsPath -> FsPath -> m ()

  Rename the file (which must exist) from the first path to the second path. If there is already a file at the latter path, it is replaced by the new one.

  NOTE: only works for files within the same folder.

• mkFsErrorPath :: FsPath -> FsErrorPath

  Useful for better error reporting

Fields

• handleRaw :: !h

  The raw underlying handle

• handlePath :: !FsPath

  The path corresponding to this handle

  This is primarily useful for error reporting.