System.FS.IO.Unix

This module is mainly meant to be used for the IO implementation of HasFS.

Documentation

type FHandle = HandleOS Fd

close :: FHandle -> IO ()

Close handle

This is a no-op when the handle is already closed.

getSize :: FHandle -> IO Word64

File size of the given file pointer

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

open :: FilePath -> OpenMode -> IO Fd

Opens a file from disk.

pread :: FHandle -> Word64 -> Word64 -> IO ByteString

preadBuf :: FHandle -> Ptr Word8 -> ByteCount -> FileOffset -> IO ByteCount

preadBuf fh buf c off reads c bytes into the buffer buf from the file handle fh at the file offset off. This does not move the position of the file handle.

pwriteBuf :: FHandle -> Ptr Word8 -> ByteCount -> FileOffset -> IO ByteCount

pwriteBuf fh buf c off writes c bytes from the data in the buffer buf to the file handle fh at the file offset off. This does not move the position of the file handle.

read :: FHandle -> Word64 -> IO ByteString

Reads a given number of bytes from the input FHandle.

readBuf :: FHandle -> Ptr Word8 -> ByteCount -> IO ByteCount

seek :: FHandle -> SeekMode -> Int64 -> IO ()

Seek within the file.

The offset may be negative.

We don't return the new offset since the behaviour of lseek is rather odd (e.g., the file pointer may not actually be moved until a subsequent write)

truncate :: FHandle -> Word64 -> IO ()

Truncates the file managed by the input FHandle to the input size.

write :: FHandle -> Ptr Word8 -> Int64 -> IO Word32

Writes the data pointed by the input 'Ptr Word8' into the input FHandle.

writeBuf :: FHandle -> Ptr Word8 -> ByteCount -> IO ByteCount