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|
{-# LANGUAGE CPP #-}
{- |
Module : System.DiskSpace
Stability : provisional
Portability : portable
-}
module System.DiskSpace
( DiskUsage(..)
, getDiskUsage
, getAvailSpace
) where
#ifndef CABAL_OS_WINDOWS
import Foreign
import Foreign.C
#include <sys/statvfs.h>
foreign import ccall safe statvfs :: CString -> Ptr a -> IO CInt
type FsBlkCnt = #type fsblkcnt_t
getDiskUsage path =
withCString path $ \cPath ->
allocaBytes (#size struct statvfs) $ \stat -> do
throwErrnoPathIfMinus1_ "getDiskUsage" path $ statvfs cPath stat
bsize <- (#peek struct statvfs, f_bsize ) stat :: IO CULong
frsize <- (#peek struct statvfs, f_frsize) stat :: IO CULong
blocks <- (#peek struct statvfs, f_blocks) stat :: IO FsBlkCnt
bfree <- (#peek struct statvfs, f_bfree ) stat :: IO FsBlkCnt
bavail <- (#peek struct statvfs, f_bavail) stat :: IO FsBlkCnt
let frsize' = fromIntegral frsize
return DiskUsage
{ diskTotal = frsize' * fromIntegral blocks
, diskFree = frsize' * fromIntegral bfree
, diskAvail = frsize' * fromIntegral bavail
, blockSize = fromIntegral bsize
}
#else
import System.Win32 (getDiskFreeSpace)
getDiskUsage path = do
(lpSectorsPerCluster,
lpBytesPerSector,
lpNumberOfFreeClusters,
lpTotalNumberOfClusters)
<- getDiskFreeSpace (Just path)
let bs = fromIntegral lpSectorsPerCluster * fromIntegral lpBytesPerSector
bs' = fromIntegral bs
to = bs' * fromIntegral lpTotalNumberOfClusters
av = bs' * fromIntegral lpNumberOfFreeClusters
return (DiskUsage to av av bs)
#endif
-- | Disk usage information. All fields are in bytes.
data DiskUsage = DiskUsage
{ diskTotal :: Integer -- ^ The total size of the file system.
, diskFree :: Integer -- ^ The amount of free space. You probably want to
-- use 'diskAvail' instead.
, diskAvail :: Integer -- ^ The amount of space available to the user.
-- Might be less than 'diskFree'. On Windows,
-- this is always equal to 'diskFree'.
-- This is what most tools report as free
-- space (e.g. the unix @df@ tool).
, blockSize :: Int -- ^ The optimal block size for I/O in this volume.
-- Some operating systems report incorrect values
-- for this field.
}
deriving (Show, Eq)
-- | Retrieve disk usage information about a volume. The volume is
-- specified with the @FilePath@ argument. The path can refer to the root
-- directory or any other directory inside the volume.
-- Unix systems also accept arbitrary files, but this
-- does not work under Windows and therefore should be avoided if
-- portability is desired.
getDiskUsage :: FilePath -> IO DiskUsage
-- | A convenience function that directly returns the 'diskAvail' field from
-- the result of 'getDiskUsage'. If a large amount of data is to be written
-- in a directory, calling this function for that directory can be used to
-- determine whether the operation will fail because of insufficient disk
-- space.
getAvailSpace :: FilePath -> IO Integer
getAvailSpace = fmap diskAvail . getDiskUsage
|
