-- |
-- Module      : Streamly.Internal.FS.Event.Linux
-- Copyright   : (c) 2020 Composewell Technologies
-- License     : BSD-3-Clause
-- Maintainer  : streamly@composewell.com
-- Stability   : experimental
-- Portability : GHC
--
-- =Overview
--
-- Use 'watchPaths' with a list of file system paths you want to watch as
-- argument. It returns a stream of 'Event' representing the file system events
-- occurring under the watched paths.
--
-- @
-- Stream.mapM_ (putStrLn . 'showEvent') $ 'watchPaths' [Path.fromString "dir"]
-- @
--
-- 'Event' is an opaque type. Accessor functions (e.g. 'showEvent' above)
-- provided in this module are used to determine the attributes of the event.
--
-- Identical successive events may be coalesced into a single event.
--
-- =Design notes
--
-- For reference documentation see:
--
-- * <https://man7.org/linux/man-pages/man7/inotify.7.html inotify man page>
--
-- We try to keep the macOS\/Linux/Windows event handling APIs and defaults
-- semantically and syntactically as close as possible.
--
-- =BUGs
--
-- When testing on Linux Kernel version @5.3.0-53-generic #47-Ubuntu@, the last
-- event for the root path seems to be delayed until one more event occurs.
--
-- = Differences between macOS and Linux APIs:
--
-- 1. macOS watch is based on the path provided to it, if the path is
-- deleted and recreated it will still be watched, if the path moves to another
-- path it won't be watched anymore. Whereas Linux watch is based on a handle
-- to the path, if the path is deleted and recreated it won't be watched, if
-- the path moves to another it can still be watched (though this is
-- configurable).
--
-- 2. macOS watches the directory hierarchy recursively, Linux watches only one
-- level of dir, recursive watch has to be built in user space by watching for
-- create events and adding the new directories to the watch. Not sure how this
-- will scale for too many paths.
--
-- 3. In macOS the path of the subject of the event is absolute, in Linux the
-- path is the name of the object inside the dir being watched.
--
-- 4. On Linux 'watchPaths' fails if a path does not exist, on macOS it does
-- not fail.

#include "config.h"

#if HAVE_DECL_IN_EXCL_UNLINK
module Streamly.Internal.FS.Event.Linux
    (
    -- * Subscribing to events

    -- ** Default configuration
      Config (..)
    , defaultConfig

    -- ** Watch Behavior
    , setRecursiveMode
    , setFollowSymLinks
    , setUnwatchMoved
    , setOneShot
    , setOnlyDir
    , WhenExists (..)
    , setWhenExists

    -- ** Events of Interest
    -- *** Root Path Events
    , setRootDeleted
    , setRootMoved
    , setRootPathEvents

    -- *** Item Level Metadata change
    , setAttrsModified

    -- *** Item Level Access
    , setAccessed
    , setOpened
    , setWriteClosed
    , setNonWriteClosed

    -- *** Item CRUD events
    , setCreated
    , setDeleted
    , setMovedFrom
    , setMovedTo
    , setModified

    , setAllEvents

    -- ** Watch APIs
    , watch
    , watchRecursive
    , watchWith

    -- Low level watch APIs
    , addToWatch
    , removeFromWatch

    -- * Handling Events
    , Event(..)
    , getRoot
    , getRelPath
    , getAbsPath
    , getCookie

    -- ** Root Level Events
    , isRootPathEvent
    , isRootUnwatched
    , isRootDeleted
    , isRootMoved
    , isRootUnmounted

    -- ** Item Level Metadata change
    , isAttrsModified

    -- ** Item Level Access
    , isAccessed
    , isOpened
    , isWriteClosed
    , isNonWriteClosed

    -- ** Item Level CRUD events
    , isCreated
    , isDeleted
    , isMovedFrom
    , isMovedTo
    , isMoved
    , isModified

    -- ** Item Path info
    , isDir

    -- ** Exception Conditions
    , isEventsLost

    -- * Debugging
    , showEvent
    )
where

import Control.Monad (void, when)
import Data.Bits ((.|.), (.&.), complement)
import Data.Foldable (foldlM)
import Data.IntMap.Lazy (IntMap)
import Data.IORef (IORef, newIORef, readIORef, writeIORef, modifyIORef)
import Data.List.NonEmpty (NonEmpty)
#if !(MIN_VERSION_base(4,13,0))
import Data.Semigroup (Semigroup(..))
#endif
import Data.Word (Word8, Word32)
import Foreign.C.Error (throwErrnoIfMinus1)
import Foreign.C.String (CString)
import Foreign.C.Types (CInt(..), CUInt(..))
import Foreign.Ptr (Ptr)
import Foreign.Storable (peek, peekByteOff, sizeOf)
import GHC.IO.Device (IODeviceType(Stream))
import GHC.IO.FD (fdFD, FD(..))
import GHC.IO.Handle.FD (mkHandleFromFD)
import Streamly.Data.Stream (Stream)
import Streamly.Data.Parser (Parser)
import System.Directory (doesDirectoryExist)
import System.IO (Handle, hClose, IOMode(ReadMode))
import GHC.IO.Handle.FD (handleToFd)

import Streamly.Internal.Data.Array (byteLength)
import Streamly.Internal.FileSystem.Path (Path)

import qualified Data.IntMap.Lazy as Map
import qualified Data.List.NonEmpty as NonEmpty
import qualified Streamly.Data.Fold as FL
import qualified Streamly.Data.Array as A (createOf)
import qualified Streamly.Data.Stream as S
import qualified Streamly.FileSystem.Handle as FH
import qualified Streamly.Internal.FileSystem.Path as Path

import qualified Streamly.Internal.Data.Array as A
    ( asCStringUnsafe, unsafePinnedAsPtr
    )
import qualified Streamly.Internal.FileSystem.DirIO as Dir (readDirs)
import qualified Streamly.Internal.Data.Parser as PR
    (takeEQ, fromEffect, fromFold)

-------------------------------------------------------------------------------
-- Subscription to events
-------------------------------------------------------------------------------

-- | Watch configuration, used to specify the events of interest and the
-- behavior of the watch.
--
-- /Pre-release/
--
data Config = Config
    { Config -> Bool
watchRec :: Bool
    , Config -> Word32
createFlags :: Word32
    }

-------------------------------------------------------------------------------
-- Boolean settings
-------------------------------------------------------------------------------

setFlag :: Word32 -> Bool -> Config -> Config
setFlag :: Word32 -> Bool -> Config -> Config
setFlag Word32
mask Bool
status cfg :: Config
cfg@Config{Bool
Word32
watchRec :: Config -> Bool
createFlags :: Config -> Word32
watchRec :: Bool
createFlags :: Word32
..} =
    let flags :: Word32
flags =
            if Bool
status
            then Word32
createFlags Word32 -> Word32 -> Word32
forall a. Bits a => a -> a -> a
.|. Word32
mask
            else Word32
createFlags Word32 -> Word32 -> Word32
forall a. Bits a => a -> a -> a
.&. Word32 -> Word32
forall a. Bits a => a -> a
complement Word32
mask
    in Config
cfg {createFlags :: Word32
createFlags = Word32
flags}

-------------------------------------------------------------------------------
-- Settings
-------------------------------------------------------------------------------

-- | Watch the whole directory tree recursively instead of watching just one
-- level of directory.
--
-- /default: False/
--
-- /Pre-release/
--
setRecursiveMode :: Bool -> Config -> Config
setRecursiveMode :: Bool -> Config -> Config
setRecursiveMode Bool
recursive cfg :: Config
cfg@Config{} = Config
cfg {watchRec :: Bool
watchRec = Bool
recursive}

foreign import capi
    "sys/inotify.h value IN_DONT_FOLLOW" iN_DONT_FOLLOW :: Word32

-- | If the pathname to be watched is a symbolic link then watch the target of
-- the symbolic link instead of the symbolic link itself.
--
-- Note that the path location in the events is through the original symbolic
-- link path rather than the resolved path.
--
-- /default: True/
--
-- /Pre-release/
--
setFollowSymLinks :: Bool -> Config -> Config
setFollowSymLinks :: Bool -> Config -> Config
setFollowSymLinks Bool
s = Word32 -> Bool -> Config -> Config
setFlag Word32
iN_DONT_FOLLOW (Bool -> Bool
not Bool
s)

foreign import capi
    "sys/inotify.h value IN_EXCL_UNLINK" iN_EXCL_UNLINK :: Word32

-- | If an object moves out of the directory being watched then stop watching
-- it.
--
-- /default: True/
--
-- /Pre-release/
--
setUnwatchMoved :: Bool -> Config -> Config
setUnwatchMoved :: Bool -> Config -> Config
setUnwatchMoved = Word32 -> Bool -> Config -> Config
setFlag Word32
iN_EXCL_UNLINK

#if HAVE_DECL_IN_MASK_CREATE
foreign import capi
    "sys/inotify.h value IN_MASK_CREATE" iN_MASK_CREATE :: Word32
#endif

foreign import capi
    "sys/inotify.h value IN_MASK_ADD" iN_MASK_ADD :: Word32

-- | What to do if a watch already exists when 'openWatch' or 'addToWatch' is
-- called for a path.
--
-- /Pre-release/
--
data WhenExists =
      AddIfExists -- ^ Do not set an existing setting to 'False' only set to 'True'
    | ReplaceIfExists -- ^ Replace the existing settings with new settings
#if HAVE_DECL_IN_MASK_CREATE
    | FailIfExists -- ^ Fail the API
#endif

-- | When adding a new path to the watch, specify what to do if a watch already
-- exists on that path.
--
-- /default: FailIfExists/
--
-- /Pre-release/
--
setWhenExists :: WhenExists -> Config -> Config
setWhenExists :: WhenExists -> Config -> Config
setWhenExists WhenExists
val Config
cfg =
    case WhenExists
val of
        WhenExists
AddIfExists -> Word32 -> Bool -> Config -> Config
setFlag Word32
iN_MASK_ADD Bool
True Config
cfg
        WhenExists
ReplaceIfExists -> Word32 -> Bool -> Config -> Config
setFlag Word32
iN_MASK_ADD Bool
False Config
cfg
#if HAVE_DECL_IN_MASK_CREATE
        WhenExists
FailIfExists -> Word32 -> Bool -> Config -> Config
setFlag Word32
iN_MASK_CREATE Bool
True Config
cfg
#endif

foreign import capi
    "sys/inotify.h value IN_ONESHOT" iN_ONESHOT :: Word32

-- | Watch the object only for one event and then remove it from the watch.
--
-- /default: False/
--
-- /Pre-release/
--
setOneShot :: Bool -> Config -> Config
setOneShot :: Bool -> Config -> Config
setOneShot = Word32 -> Bool -> Config -> Config
setFlag Word32
iN_ONESHOT

foreign import capi
    "sys/inotify.h value IN_ONLYDIR" iN_ONLYDIR :: Word32

-- | Watch the object only if it is a directory. This provides a race-free way
-- to ensure that the watched object is a directory.
--
-- /default: False/
--
-- /Pre-release/
--
setOnlyDir :: Bool -> Config -> Config
setOnlyDir :: Bool -> Config -> Config
setOnlyDir = Word32 -> Bool -> Config -> Config
setFlag Word32
iN_ONLYDIR

-------------------------------------------------------------------------------
-- Event types that can occur
-------------------------------------------------------------------------------

foreign import capi
    "sys/inotify.h value IN_DELETE_SELF" iN_DELETE_SELF :: Word32

-- | Report when the watched path itself gets deleted.
--
-- /default: True/
--
-- /Pre-release/
--
setRootDeleted :: Bool -> Config -> Config
setRootDeleted :: Bool -> Config -> Config
setRootDeleted = Word32 -> Bool -> Config -> Config
setFlag Word32
iN_DELETE_SELF

foreign import capi
    "sys/inotify.h value IN_MOVE_SELF" iN_MOVE_SELF :: Word32

-- | Report when the watched root path itself gets renamed.
--
-- /default: True/
--
-- /Pre-release/
--
setRootMoved :: Bool -> Config -> Config
setRootMoved :: Bool -> Config -> Config
setRootMoved = Word32 -> Bool -> Config -> Config
setFlag Word32
iN_MOVE_SELF

-- | Report when the watched root path itself gets deleted or renamed.
--
-- /default: True/
--
-- /Pre-release/
--
setRootPathEvents :: Bool -> Config -> Config
setRootPathEvents :: Bool -> Config -> Config
setRootPathEvents = Word32 -> Bool -> Config -> Config
setFlag (Word32
iN_DELETE_SELF Word32 -> Word32 -> Word32
forall a. Bits a => a -> a -> a
.|. Word32
iN_MOVE_SELF)

foreign import capi
    "sys/inotify.h value IN_ATTRIB" iN_ATTRIB :: Word32

-- | Report when the metadata e.g. owner, permission modes, modifications times
-- of an object changes.
--
-- /default: True/
--
-- /Pre-release/
--
setAttrsModified :: Bool -> Config -> Config
setAttrsModified :: Bool -> Config -> Config
setAttrsModified = Word32 -> Bool -> Config -> Config
setFlag Word32
iN_ATTRIB

foreign import capi
    "sys/inotify.h value IN_ACCESS" iN_ACCESS :: Word32

-- | Report when a file is accessed.
--
-- /default: True/
--
-- /Pre-release/
--
setAccessed :: Bool -> Config -> Config
setAccessed :: Bool -> Config -> Config
setAccessed = Word32 -> Bool -> Config -> Config
setFlag Word32
iN_ACCESS

foreign import capi
    "sys/inotify.h value IN_OPEN" iN_OPEN :: Word32

-- | Report when a file is opened.
--
-- /default: True/
--
-- /Pre-release/
--
setOpened :: Bool -> Config -> Config
setOpened :: Bool -> Config -> Config
setOpened = Word32 -> Bool -> Config -> Config
setFlag Word32
iN_OPEN

foreign import capi
    "sys/inotify.h value IN_CLOSE_WRITE" iN_CLOSE_WRITE :: Word32

-- | Report when a file that was opened for writes is closed.
--
-- /default: True/
--
-- /Pre-release/
--
setWriteClosed :: Bool -> Config -> Config
setWriteClosed :: Bool -> Config -> Config
setWriteClosed = Word32 -> Bool -> Config -> Config
setFlag Word32
iN_CLOSE_WRITE

foreign import capi
    "sys/inotify.h value IN_CLOSE_NOWRITE" iN_CLOSE_NOWRITE :: Word32

-- | Report when a file that was opened for not writing is closed.
--
-- /default: True/
--
-- /Pre-release/
--
setNonWriteClosed :: Bool -> Config -> Config
setNonWriteClosed :: Bool -> Config -> Config
setNonWriteClosed = Word32 -> Bool -> Config -> Config
setFlag Word32
iN_CLOSE_NOWRITE

foreign import capi
    "sys/inotify.h value IN_CREATE" iN_CREATE :: Word32

-- | Report when a file is created.
--
-- /default: True/
--
-- /Pre-release/
--
setCreated :: Bool -> Config -> Config
setCreated :: Bool -> Config -> Config
setCreated = Word32 -> Bool -> Config -> Config
setFlag Word32
iN_CREATE

foreign import capi
    "sys/inotify.h value IN_DELETE" iN_DELETE :: Word32

-- | Report when a file is deleted.
--
-- /default: True/
--
-- /Pre-release/
--
setDeleted :: Bool -> Config -> Config
setDeleted :: Bool -> Config -> Config
setDeleted = Word32 -> Bool -> Config -> Config
setFlag Word32
iN_DELETE

foreign import capi
    "sys/inotify.h value IN_MOVED_FROM" iN_MOVED_FROM :: Word32

-- | Report the source of a move.
--
-- /default: True/
--
-- /Pre-release/
--
setMovedFrom :: Bool -> Config -> Config
setMovedFrom :: Bool -> Config -> Config
setMovedFrom = Word32 -> Bool -> Config -> Config
setFlag Word32
iN_MOVED_FROM

foreign import capi
    "sys/inotify.h value IN_MOVED_TO" iN_MOVED_TO :: Word32

-- | Report the target of a move.
--
-- /default: True/
--
-- /Pre-release/
--
setMovedTo :: Bool -> Config -> Config
setMovedTo :: Bool -> Config -> Config
setMovedTo = Word32 -> Bool -> Config -> Config
setFlag Word32
iN_MOVED_TO

foreign import capi
    "sys/inotify.h value IN_MODIFY" iN_MODIFY :: Word32

-- | Report when a file is modified.
--
-- /default: True/
--
-- /Pre-release/
--
setModified :: Bool -> Config -> Config
setModified :: Bool -> Config -> Config
setModified = Word32 -> Bool -> Config -> Config
setFlag Word32
iN_MODIFY

-- | Set all tunable events 'True' or 'False'. Equivalent to setting:
--
-- * setRootDeleted
-- * setRootMoved
-- * setAttrsModified
-- * setAccessed
-- * setOpened
-- * setWriteClosed
-- * setNonWriteClosed
-- * setCreated
-- * setDeleted
-- * setMovedFrom
-- * setMovedTo
-- * setModified
--
-- /Pre-release/
--
setAllEvents :: Bool -> Config -> Config
setAllEvents :: Bool -> Config -> Config
setAllEvents Bool
s =
      Bool -> Config -> Config
setRootDeleted Bool
s
    (Config -> Config) -> (Config -> Config) -> Config -> Config
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Bool -> Config -> Config
setRootMoved Bool
s
    (Config -> Config) -> (Config -> Config) -> Config -> Config
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Bool -> Config -> Config
setAttrsModified Bool
s
    (Config -> Config) -> (Config -> Config) -> Config -> Config
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Bool -> Config -> Config
setAccessed Bool
s
    (Config -> Config) -> (Config -> Config) -> Config -> Config
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Bool -> Config -> Config
setOpened Bool
s
    (Config -> Config) -> (Config -> Config) -> Config -> Config
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Bool -> Config -> Config
setWriteClosed Bool
s
    (Config -> Config) -> (Config -> Config) -> Config -> Config
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Bool -> Config -> Config
setNonWriteClosed Bool
s
    (Config -> Config) -> (Config -> Config) -> Config -> Config
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Bool -> Config -> Config
setCreated Bool
s
    (Config -> Config) -> (Config -> Config) -> Config -> Config
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Bool -> Config -> Config
setDeleted Bool
s
    (Config -> Config) -> (Config -> Config) -> Config -> Config
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Bool -> Config -> Config
setMovedFrom Bool
s
    (Config -> Config) -> (Config -> Config) -> Config -> Config
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Bool -> Config -> Config
setMovedTo Bool
s
    (Config -> Config) -> (Config -> Config) -> Config -> Config
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Bool -> Config -> Config
setModified Bool
s

-------------------------------------------------------------------------------
-- Default config
-------------------------------------------------------------------------------

-- The defaults are set in such a way that the behavior on macOS and Linux is
-- as much compatible as possible.
--
-- | The default configuration settings are:
--
-- * 'setFollowSymLinks' 'True'
-- * 'setUnwatchMoved' 'True'
-- * 'setOneShot' 'False'
-- * 'setOnlyDir' 'False'
-- * 'setWhenExists' 'AddIfExists'
--
-- The tunable events enabled by default are:
--
-- * setCreated True
-- * setDeleted True
-- * setMovedFrom True
-- * setMovedTo True
-- * setModified True
--
-- /Pre-release/
--
defaultConfig :: Config
defaultConfig :: Config
defaultConfig =
      WhenExists -> Config -> Config
setWhenExists WhenExists
AddIfExists
    (Config -> Config) -> Config -> Config
forall a b. (a -> b) -> a -> b
$ Bool -> Config -> Config
setCreated Bool
True
    (Config -> Config) -> Config -> Config
forall a b. (a -> b) -> a -> b
$ Bool -> Config -> Config
setDeleted Bool
True
    (Config -> Config) -> Config -> Config
forall a b. (a -> b) -> a -> b
$ Bool -> Config -> Config
setMovedFrom Bool
True
    (Config -> Config) -> Config -> Config
forall a b. (a -> b) -> a -> b
$ Bool -> Config -> Config
setMovedTo Bool
True
    (Config -> Config) -> Config -> Config
forall a b. (a -> b) -> a -> b
$ Bool -> Config -> Config
setModified Bool
True
    (Config -> Config) -> Config -> Config
forall a b. (a -> b) -> a -> b
$ Config
        { watchRec :: Bool
watchRec = Bool
False
        , createFlags :: Word32
createFlags = Word32
0
        }

-------------------------------------------------------------------------------
-- Path representation for events
-------------------------------------------------------------------------------

type PathRep =
    ( Path       -- Absolute path of the watch root
    , Maybe Path -- Path of subdir relative to watch root
    )

{-# INLINE combinePathRep #-}
combinePathRep :: PathRep -> Path
combinePathRep :: PathRep -> PosixPath
combinePathRep (PosixPath
root, Maybe PosixPath
Nothing) = PosixPath
root
combinePathRep (PosixPath
root, Just PosixPath
sub) = PosixPath -> PosixPath -> PosixPath
Path.append PosixPath
root PosixPath
sub

{-# INLINE addSub #-}
addSub :: PathRep -> Path -> PathRep
addSub :: PathRep -> PosixPath -> PathRep
addSub (PosixPath
root, Maybe PosixPath
Nothing) PosixPath
sub = (PosixPath
root, PosixPath -> Maybe PosixPath
forall a. a -> Maybe a
Just PosixPath
sub)
addSub (PosixPath
root, Just PosixPath
sub0) PosixPath
sub1 = (PosixPath
root, PosixPath -> Maybe PosixPath
forall a. a -> Maybe a
Just (PosixPath -> PosixPath -> PosixPath
Path.append PosixPath
sub0 PosixPath
sub1))

{-# INLINE getRepRoot #-}
getRepRoot :: PathRep -> Path
getRepRoot :: PathRep -> PosixPath
getRepRoot = PathRep -> PosixPath
forall a b. (a, b) -> a
fst

{-# INLINE getRepSub #-}
getRepSub :: PathRep -> Maybe Path
getRepSub :: PathRep -> Maybe PosixPath
getRepSub = PathRep -> Maybe PosixPath
forall a b. (a, b) -> b
snd

-------------------------------------------------------------------------------
-- Open an event stream
-------------------------------------------------------------------------------

-- | A handle for a watch.
data Watch =
    Watch
        Handle                  -- File handle for the watch
        (IORef
            (IntMap             -- Key is the watch descriptor
                PathRep
            )
        )

-- Instead of using the watch descriptor we can provide APIs that use the path
-- itself to identify the watch. That will require us to maintain a map from wd
-- to path in the Watch handle.

newtype WD = WD CInt deriving Key -> WD -> ShowS
[WD] -> ShowS
WD -> [Char]
(Key -> WD -> ShowS)
-> (WD -> [Char]) -> ([WD] -> ShowS) -> Show WD
forall a.
(Key -> a -> ShowS) -> (a -> [Char]) -> ([a] -> ShowS) -> Show a
$cshowsPrec :: Key -> WD -> ShowS
showsPrec :: Key -> WD -> ShowS
$cshow :: WD -> [Char]
show :: WD -> [Char]
$cshowList :: [WD] -> ShowS
showList :: [WD] -> ShowS
Show

-- XXX Use inotify_init1? and IN_NONBLOCK?
foreign import ccall unsafe
    "sys/inotify.h inotify_init" c_inotify_init :: IO CInt

-- | Create a 'Watch' handle. 'addToWatch' can be used to add paths being
-- monitored by this watch.
--
-- /Pre-release/
--
createWatch :: IO Watch
createWatch :: IO Watch
createWatch = do
    CInt
rawfd <- [Char] -> IO CInt -> IO CInt
forall a. (Eq a, Num a) => [Char] -> IO a -> IO a
throwErrnoIfMinus1 [Char]
"createWatch" IO CInt
c_inotify_init
    -- We could use fdToHandle but it cannot determine the fd type
    -- automatically for the inotify fd because fdStat fails for Stream type
    -- fd.
    --
    -- Do not use mkFD as it locks a regular file causing "resource busy" error
    -- in some test cases.
    let fd :: FD
fd =
            FD
                { fdFD :: CInt
fdFD = CInt
rawfd
#if !defined(mingw32_HOST_OS)
                , fdIsNonBlocking :: Key
fdIsNonBlocking = Key
0
#else
                , fdIsSocket_ = 0
#endif
              }

    -- XXX Do we need non-blocking IO?
    -- With non-blocking IO it fails because GHC-9.10 uses fdStat in
    -- FD.setNonBlockingMode to determine the fd type which fails for Stream
    -- type fd. However, without non-blocking IO "select" has a limitation on
    -- the number of FDs being watched (1024).
    Handle
h <-
        FD
-> IODeviceType
-> [Char]
-> IOMode
-> Bool
-> Maybe TextEncoding
-> IO Handle
mkHandleFromFD
           FD
fd
           IODeviceType
Stream
           ([Char]
"<createWatch fd: " [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ FD -> [Char]
forall a. Show a => a -> [Char]
show FD
fd [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ [Char]
">")
           IOMode
ReadMode
           Bool
False    -- use non-blocking IO
           Maybe TextEncoding
forall a. Maybe a
Nothing -- TextEncoding (binary)
    IORef (IntMap PathRep)
emptyMapRef <- IntMap PathRep -> IO (IORef (IntMap PathRep))
forall a. a -> IO (IORef a)
newIORef IntMap PathRep
forall a. IntMap a
Map.empty
    Watch -> IO Watch
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return (Watch -> IO Watch) -> Watch -> IO Watch
forall a b. (a -> b) -> a -> b
$ Handle -> IORef (IntMap PathRep) -> Watch
Watch Handle
h IORef (IntMap PathRep)
emptyMapRef

foreign import ccall unsafe
    "sys/inotify.h inotify_add_watch" c_inotify_add_watch
        :: CInt -> CString -> CUInt -> IO CInt

-- | @addToWatch cfg watch root subpath@ adds @subpath@ to the list of paths
-- being monitored under @root@ via the watch handle @watch@.  @root@ must be
-- an absolute path and @subpath@ must be relative to @root@.
--
-- /Pre-release/
--
addToWatch :: Config -> Watch -> PathRep -> IO ()
addToWatch :: Config -> Watch -> PathRep -> IO ()
addToWatch cfg :: Config
cfg@Config{Bool
Word32
watchRec :: Config -> Bool
createFlags :: Config -> Word32
watchRec :: Bool
createFlags :: Word32
..} watch0 :: Watch
watch0@(Watch Handle
handle IORef (IntMap PathRep)
wdMap) PathRep
prep = do
    -- XXX do not add if the path is already added
    -- XXX if the watch is added by the scan and not via an event we can
    -- generate a create event assuming that the create may have been lost. We
    -- can also mark in the map that this entry was added by the scan. So if an
    -- actual create event later comes and tries to add this again then we can
    -- ignore that and drop the create event to avoid duplicate create, because
    -- we have already emitted it.
    --
    -- When a directory is added by the scan we should also emit create events
    -- for files that may have got added to the dir. However, such create
    -- events may get duplicated because of a race between the scan generated
    -- versus real events.
    --
    -- Or we may distinguish between scan generated events and real events so
    -- that the application can assume that other events may been lost and
    -- handle it. For example, if it is a dir create the application can read
    -- the dir to scan the files in it.
    --
    let absPath :: PosixPath
absPath = PathRep -> PosixPath
combinePathRep PathRep
prep
    --    showPathRep (root, Nothing) = "root = " ++ Path.toString root
    --    showPathRep (root, Just sub) =
    --        "root = " ++ Path.toString root ++ " sub = " ++ Path.toString sub
    -- putStrLn $ showPathRep prep ++ " absPath = " ++ Path.toString absPath

    FD
fd <- Handle -> IO FD
handleToFd Handle
handle

    -- XXX we need to tolerate an error where we are adding a watch for a
    -- non-existing file because the file may have got deleted by the time we
    -- added the watch. Perhaps we can have a flag in config for this and keep
    -- the default value to tolerate the error.
    --
    -- XXX The file may have even got deleted and then recreated which we will
    -- never get to know, document this.
    CInt
wd <- Array Word8 -> (CString -> IO CInt) -> IO CInt
forall a b. Array a -> (CString -> IO b) -> IO b
A.asCStringUnsafe (PosixPath -> Array Word8
forall a. IsPath PosixPath a => a -> Array Word8
Path.toChunk PosixPath
absPath) ((CString -> IO CInt) -> IO CInt)
-> (CString -> IO CInt) -> IO CInt
forall a b. (a -> b) -> a -> b
$ \CString
pathPtr ->
            [Char] -> IO CInt -> IO CInt
forall a. (Eq a, Num a) => [Char] -> IO a -> IO a
throwErrnoIfMinus1 ([Char]
"addToWatch: " [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ PosixPath -> [Char]
forall a. IsPath PosixPath a => a -> [Char]
Path.toString PosixPath
absPath) (IO CInt -> IO CInt) -> IO CInt -> IO CInt
forall a b. (a -> b) -> a -> b
$
                CInt -> CString -> CUInt -> IO CInt
c_inotify_add_watch (FD -> CInt
fdFD FD
fd) CString
pathPtr (Word32 -> CUInt
CUInt Word32
createFlags)

    -- We add the parent first so that we start getting events for any new
    -- creates and add the new subdirectories on creates while we are adding
    -- the children.
    IORef (IntMap PathRep)
-> (IntMap PathRep -> IntMap PathRep) -> IO ()
forall a. IORef a -> (a -> a) -> IO ()
modifyIORef IORef (IntMap PathRep)
wdMap (Key -> PathRep -> IntMap PathRep -> IntMap PathRep
forall a. Key -> a -> IntMap a -> IntMap a
Map.insert (CInt -> Key
forall a b. (Integral a, Num b) => a -> b
fromIntegral CInt
wd) PathRep
prep)

    -- Now add the children. If we missed any creates while we were adding the
    -- parent, this will make sure they are added too.
    --
    -- XXX Ensure that we generate events that we may have missed while we were
    -- adding the dirs. That may generate spurious events though.
    --
    -- XXX readDirs currently uses paths as String, we need to convert it
    -- to "/" separated by byte arrays.
    -- XXX Need a FileSystem.Stat module to remove this
    Bool
pathIsDir <- [Char] -> IO Bool
doesDirectoryExist (PosixPath -> [Char]
forall a. IsPath PosixPath a => a -> [Char]
Path.toString PosixPath
absPath)
    Bool -> IO () -> IO ()
forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when (Bool
watchRec Bool -> Bool -> Bool
&& Bool
pathIsDir) (IO () -> IO ()) -> IO () -> IO ()
forall a b. (a -> b) -> a -> b
$ do
        let f :: PosixPath -> IO ()
f = Config -> Watch -> PathRep -> IO ()
addToWatch Config
cfg Watch
watch0 (PathRep -> IO ()) -> (PosixPath -> PathRep) -> PosixPath -> IO ()
forall b c a. (b -> c) -> (a -> b) -> a -> c
. PathRep -> PosixPath -> PathRep
addSub PathRep
prep
            in Fold IO PosixPath () -> Stream IO PosixPath -> IO ()
forall (m :: * -> *) a b.
Monad m =>
Fold m a b -> Stream m a -> m b
S.fold ((PosixPath -> IO ()) -> Fold IO PosixPath ()
forall (m :: * -> *) a b. Monad m => (a -> m b) -> Fold m a ()
FL.drainMapM PosixPath -> IO ()
f) (Stream IO PosixPath -> IO ()) -> Stream IO PosixPath -> IO ()
forall a b. (a -> b) -> a -> b
$ PosixPath -> Stream IO PosixPath
forall (m :: * -> *).
(MonadIO m, MonadCatch m) =>
PosixPath -> Stream m PosixPath
Dir.readDirs PosixPath
absPath

foreign import ccall unsafe
    "sys/inotify.h inotify_rm_watch" c_inotify_rm_watch
        :: CInt -> CInt -> IO CInt

-- | Remove an absolute root path from a 'Watch', if a path was moved after
-- adding you need to provide the original path which was used to add the
-- Watch.
--
-- /Pre-release/
--
removeFromWatch :: Watch -> Path -> IO ()
removeFromWatch :: Watch -> PosixPath -> IO ()
removeFromWatch (Watch Handle
handle IORef (IntMap PathRep)
wdMap) PosixPath
root = do
    FD
fd <- Handle -> IO FD
handleToFd Handle
handle
    IntMap PathRep
km <- IORef (IntMap PathRep) -> IO (IntMap PathRep)
forall a. IORef a -> IO a
readIORef IORef (IntMap PathRep)
wdMap
    IntMap PathRep
wdMap1 <- (IntMap PathRep -> (Key, PathRep) -> IO (IntMap PathRep))
-> IntMap PathRep -> [(Key, PathRep)] -> IO (IntMap PathRep)
forall (t :: * -> *) (m :: * -> *) b a.
(Foldable t, Monad m) =>
(b -> a -> m b) -> b -> t a -> m b
foldlM (FD -> IntMap PathRep -> (Key, PathRep) -> IO (IntMap PathRep)
step FD
fd) IntMap PathRep
forall a. IntMap a
Map.empty (IntMap PathRep -> [(Key, PathRep)]
forall a. IntMap a -> [(Key, a)]
Map.toList IntMap PathRep
km)
    IORef (IntMap PathRep) -> IntMap PathRep -> IO ()
forall a. IORef a -> a -> IO ()
writeIORef IORef (IntMap PathRep)
wdMap IntMap PathRep
wdMap1

    where

    step :: FD -> IntMap PathRep -> (Key, PathRep) -> IO (IntMap PathRep)
step FD
fd IntMap PathRep
newMap (Key
wd, PathRep
v) = do
        -- XXX Path is currently not guaranteed to be normalized.
        -- See: https://github.com/composewell/streamly/issues/2888
        if PosixPath -> Array Word8
forall a. IsPath PosixPath a => a -> Array Word8
Path.toChunk (PathRep -> PosixPath
getRepRoot PathRep
v) Array Word8 -> Array Word8 -> Bool
forall a. Eq a => a -> a -> Bool
== PosixPath -> Array Word8
forall a. IsPath PosixPath a => a -> Array Word8
Path.toChunk PosixPath
root
        then do
            let err :: [Char]
err = [Char]
"removeFromWatch: " [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ ShowS
forall a. Show a => a -> [Char]
show (PosixPath -> [Char]
forall a. IsPath PosixPath a => a -> [Char]
Path.toString PosixPath
root)
                rm :: IO CInt
rm = CInt -> CInt -> IO CInt
c_inotify_rm_watch (FD -> CInt
fdFD FD
fd) (Key -> CInt
forall a b. (Integral a, Num b) => a -> b
fromIntegral Key
wd)
            IO CInt -> IO ()
forall (f :: * -> *) a. Functor f => f a -> f ()
void (IO CInt -> IO ()) -> IO CInt -> IO ()
forall a b. (a -> b) -> a -> b
$ [Char] -> IO CInt -> IO CInt
forall a. (Eq a, Num a) => [Char] -> IO a -> IO a
throwErrnoIfMinus1 [Char]
err IO CInt
rm
            IntMap PathRep -> IO (IntMap PathRep)
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return IntMap PathRep
newMap
        else IntMap PathRep -> IO (IntMap PathRep)
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return (IntMap PathRep -> IO (IntMap PathRep))
-> IntMap PathRep -> IO (IntMap PathRep)
forall a b. (a -> b) -> a -> b
$ Key -> PathRep -> IntMap PathRep -> IntMap PathRep
forall a. Key -> a -> IntMap a -> IntMap a
Map.insert Key
wd PathRep
v IntMap PathRep
newMap

-- | Given a 'Config' and list of @paths@ ("/" separated byte arrays) start
-- monitoring the paths for file system events. Returns a 'Watch' handle which
-- can then be used to read the event stream or to close the watch.
--
-- /Pre-release/
--
openWatch :: Config -> NonEmpty Path -> IO Watch
openWatch :: Config -> NonEmpty PosixPath -> IO Watch
openWatch Config
cfg NonEmpty PosixPath
paths = do
    Watch
w <- IO Watch
createWatch
    (PosixPath -> IO ()) -> [PosixPath] -> IO ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ (\PosixPath
root -> Config -> Watch -> PathRep -> IO ()
addToWatch Config
cfg Watch
w (PosixPath
root, Maybe PosixPath
forall a. Maybe a
Nothing)) ([PosixPath] -> IO ()) -> [PosixPath] -> IO ()
forall a b. (a -> b) -> a -> b
$ NonEmpty PosixPath -> [PosixPath]
forall a. NonEmpty a -> [a]
NonEmpty.toList NonEmpty PosixPath
paths
    Watch -> IO Watch
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return Watch
w

-- | Close a 'Watch' handle.
--
-- /Pre-release/
--
closeWatch :: Watch -> IO ()
closeWatch :: Watch -> IO ()
closeWatch (Watch Handle
h IORef (IntMap PathRep)
_) = Handle -> IO ()
hClose Handle
h

-------------------------------------------------------------------------------
-- Raw events read from the watch file handle
-------------------------------------------------------------------------------

newtype Cookie = Cookie Word32 deriving (Key -> Cookie -> ShowS
[Cookie] -> ShowS
Cookie -> [Char]
(Key -> Cookie -> ShowS)
-> (Cookie -> [Char]) -> ([Cookie] -> ShowS) -> Show Cookie
forall a.
(Key -> a -> ShowS) -> (a -> [Char]) -> ([a] -> ShowS) -> Show a
$cshowsPrec :: Key -> Cookie -> ShowS
showsPrec :: Key -> Cookie -> ShowS
$cshow :: Cookie -> [Char]
show :: Cookie -> [Char]
$cshowList :: [Cookie] -> ShowS
showList :: [Cookie] -> ShowS
Show, Cookie -> Cookie -> Bool
(Cookie -> Cookie -> Bool)
-> (Cookie -> Cookie -> Bool) -> Eq Cookie
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
$c== :: Cookie -> Cookie -> Bool
== :: Cookie -> Cookie -> Bool
$c/= :: Cookie -> Cookie -> Bool
/= :: Cookie -> Cookie -> Bool
Eq)

-- | An Event generated by the file system. Use the accessor functions to
-- examine the event.
--
-- /Pre-release/
--
data Event = Event
   { Event -> CInt
eventWd :: CInt
   , Event -> Word32
eventFlags :: Word32
   , Event -> Word32
eventCookie :: Word32
   , Event -> Maybe PosixPath
eventRelPath :: Maybe Path
   , Event -> IntMap PathRep
eventMap :: IntMap PathRep
   }

-- The inotify event struct from the man page/header file:
--
--            struct inotify_event {
--                int      wd;       /* Watch descriptor */
--                uint32_t mask;     /* Mask describing event */
--                uint32_t cookie;   /* Unique cookie associating related
--                                      events (for rename(2)) */
--                uint32_t len;      /* Size of name field */
--                char     name[];   /* Optional null-terminated name */
--            };
--
-- XXX We can perhaps use parseD monad instance for fusing with parseMany? Need
-- to measure the perf.
--
readOneEvent :: Config -> Watch -> Parser Word8 IO Event
readOneEvent :: Config -> Watch -> Parser Word8 IO Event
readOneEvent Config
cfg  wt :: Watch
wt@(Watch Handle
_ IORef (IntMap PathRep)
wdMap) = do
    let headerLen :: Key
headerLen = CInt -> Key
forall a. Storable a => a -> Key
sizeOf (CInt
forall a. HasCallStack => a
undefined :: CInt) Key -> Key -> Key
forall a. Num a => a -> a -> a
+ Key
12
    Array Word8
arr <- Key -> Fold IO Word8 (Array Word8) -> Parser Word8 IO (Array Word8)
forall (m :: * -> *) a b.
Monad m =>
Key -> Fold m a b -> Parser a m b
PR.takeEQ Key
headerLen (Key -> Fold IO Word8 (Array Word8)
forall (m :: * -> *) a.
(MonadIO m, Unbox a) =>
Key -> Fold m a (Array a)
A.createOf Key
headerLen)
    (Word8
ewd, Word32
eflags, Word32
cookie, Key
pathLen) <- IO (Word8, Word32, Word32, Key)
-> Parser Word8 IO (Word8, Word32, Word32, Key)
forall (m :: * -> *) b a. Monad m => m b -> Parser a m b
PR.fromEffect (IO (Word8, Word32, Word32, Key)
 -> Parser Word8 IO (Word8, Word32, Word32, Key))
-> IO (Word8, Word32, Word32, Key)
-> Parser Word8 IO (Word8, Word32, Word32, Key)
forall a b. (a -> b) -> a -> b
$ Array Word8
-> (Ptr Word8 -> Key -> IO (Word8, Word32, Word32, Key))
-> IO (Word8, Word32, Word32, Key)
forall (m :: * -> *) a b.
MonadIO m =>
Array a -> (Ptr a -> Key -> IO b) -> m b
A.unsafePinnedAsPtr Array Word8
arr Ptr Word8 -> Key -> IO (Word8, Word32, Word32, Key)
forall {b} {c} {d} {p}.
(Storable b, Storable c, Num d) =>
Ptr Word8 -> p -> IO (Word8, b, c, d)
readHeader
    -- XXX need the "initial" in parsers to return a step type so that "take 0"
    -- can return without an input. otherwise if pathLen is 0 we will keep
    -- waiting to read one more char before we return this event.
    IntMap PathRep
wdm <- IO (IntMap PathRep) -> Parser Word8 IO (IntMap PathRep)
forall (m :: * -> *) b a. Monad m => m b -> Parser a m b
PR.fromEffect (IO (IntMap PathRep) -> Parser Word8 IO (IntMap PathRep))
-> IO (IntMap PathRep) -> Parser Word8 IO (IntMap PathRep)
forall a b. (a -> b) -> a -> b
$ IORef (IntMap PathRep) -> IO (IntMap PathRep)
forall a. IORef a -> IO a
readIORef IORef (IntMap PathRep)
wdMap
    let prep :: PathRep
prep =
            case Key -> IntMap PathRep -> Maybe PathRep
forall a. Key -> IntMap a -> Maybe a
Map.lookup (Word8 -> Key
forall a b. (Integral a, Num b) => a -> b
fromIntegral Word8
ewd) IntMap PathRep
wdm of
                    Just PathRep
prep0 -> PathRep
prep0
                    Maybe PathRep
Nothing ->
                        [Char] -> PathRep
forall a. HasCallStack => [Char] -> a
error ([Char] -> PathRep) -> [Char] -> PathRep
forall a b. (a -> b) -> a -> b
$ [Char]
"readOneEvent: "
                                  [Char] -> ShowS
forall a. Semigroup a => a -> a -> a
<> [Char]
"Unknown watch descriptor: "
                                  [Char] -> ShowS
forall a. Semigroup a => a -> a -> a
<> Word8 -> [Char]
forall a. Show a => a -> [Char]
show Word8
ewd
    PathRep
prep1 <-
        if Key
pathLen Key -> Key -> Bool
forall a. Eq a => a -> a -> Bool
/= Key
0
        then do
            -- XXX takeEndBy_ drops the separator so assumes a null
            -- terminated path, we should use a takeWhile nested inside a
            -- takeP
            Array Word8
pth <-
                Fold IO Word8 (Array Word8) -> Parser Word8 IO (Array Word8)
forall (m :: * -> *) a b. Monad m => Fold m a b -> Parser a m b
PR.fromFold
                    (Fold IO Word8 (Array Word8) -> Parser Word8 IO (Array Word8))
-> Fold IO Word8 (Array Word8) -> Parser Word8 IO (Array Word8)
forall a b. (a -> b) -> a -> b
$ (Word8 -> Bool)
-> Fold IO Word8 (Array Word8) -> Fold IO Word8 (Array Word8)
forall (m :: * -> *) a b.
Monad m =>
(a -> Bool) -> Fold m a b -> Fold m a b
FL.takeEndBy_ (Word8 -> Word8 -> Bool
forall a. Eq a => a -> a -> Bool
== Word8
0)
                    (Fold IO Word8 (Array Word8) -> Fold IO Word8 (Array Word8))
-> Fold IO Word8 (Array Word8) -> Fold IO Word8 (Array Word8)
forall a b. (a -> b) -> a -> b
$ Key -> Fold IO Word8 (Array Word8) -> Fold IO Word8 (Array Word8)
forall (m :: * -> *) a b.
Monad m =>
Key -> Fold m a b -> Fold m a b
FL.take Key
pathLen (Key -> Fold IO Word8 (Array Word8)
forall (m :: * -> *) a.
(MonadIO m, Unbox a) =>
Key -> Fold m a (Array a)
A.createOf Key
pathLen)
            let remaining :: Key
remaining = Key
pathLen Key -> Key -> Key
forall a. Num a => a -> a -> a
- Array Word8 -> Key
forall a. Array a -> Key
byteLength Array Word8
pth Key -> Key -> Key
forall a. Num a => a -> a -> a
- Key
1
            Bool -> Parser Word8 IO () -> Parser Word8 IO ()
forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when (Key
remaining Key -> Key -> Bool
forall a. Eq a => a -> a -> Bool
/= Key
0) (Parser Word8 IO () -> Parser Word8 IO ())
-> Parser Word8 IO () -> Parser Word8 IO ()
forall a b. (a -> b) -> a -> b
$ Key -> Fold IO Word8 () -> Parser Word8 IO ()
forall (m :: * -> *) a b.
Monad m =>
Key -> Fold m a b -> Parser a m b
PR.takeEQ Key
remaining Fold IO Word8 ()
forall (m :: * -> *) a. Monad m => Fold m a ()
FL.drain
            PathRep -> Parser Word8 IO PathRep
forall a. a -> Parser Word8 IO a
forall (m :: * -> *) a. Monad m => a -> m a
return (PathRep -> Parser Word8 IO PathRep)
-> PathRep -> Parser Word8 IO PathRep
forall a b. (a -> b) -> a -> b
$ PathRep -> PosixPath -> PathRep
addSub PathRep
prep (Array Word8 -> PosixPath
forall a. IsPath PosixPath a => Array Word8 -> a
Path.unsafeFromChunk Array Word8
pth)
        else PathRep -> Parser Word8 IO PathRep
forall a. a -> Parser Word8 IO a
forall (m :: * -> *) a. Monad m => a -> m a
return (PathRep -> Parser Word8 IO PathRep)
-> PathRep -> Parser Word8 IO PathRep
forall a b. (a -> b) -> a -> b
$ PathRep
prep
    -- Check for "ISDIR" first because it is less likely
    let isDirCreate :: Bool
isDirCreate = Word32
eflags Word32 -> Word32 -> Word32
forall a. Bits a => a -> a -> a
.&. Word32
iN_ISDIR Word32 -> Word32 -> Bool
forall a. Eq a => a -> a -> Bool
/= Word32
0 Bool -> Bool -> Bool
&& Word32
eflags Word32 -> Word32 -> Word32
forall a. Bits a => a -> a -> a
.&. Word32
iN_CREATE Word32 -> Word32 -> Bool
forall a. Eq a => a -> a -> Bool
/= Word32
0
    Bool -> Parser Word8 IO () -> Parser Word8 IO ()
forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when (Config -> Bool
watchRec Config
cfg Bool -> Bool -> Bool
&& Bool
isDirCreate)
        (Parser Word8 IO () -> Parser Word8 IO ())
-> Parser Word8 IO () -> Parser Word8 IO ()
forall a b. (a -> b) -> a -> b
$ IO () -> Parser Word8 IO ()
forall (m :: * -> *) b a. Monad m => m b -> Parser a m b
PR.fromEffect (IO () -> Parser Word8 IO ()) -> IO () -> Parser Word8 IO ()
forall a b. (a -> b) -> a -> b
$ Config -> Watch -> PathRep -> IO ()
addToWatch Config
cfg Watch
wt PathRep
prep1
    -- XXX Handle IN_DELETE, IN_DELETE_SELF, IN_MOVE_SELF, IN_MOVED_FROM,
    -- IN_MOVED_TO
    -- What if a large dir tree gets moved in to our hierarchy? Do we get a
    -- single event for the top level dir in this case?
    Event -> Parser Word8 IO Event
forall a. a -> Parser Word8 IO a
forall (m :: * -> *) a. Monad m => a -> m a
return (Event -> Parser Word8 IO Event) -> Event -> Parser Word8 IO Event
forall a b. (a -> b) -> a -> b
$ Event
        { eventWd :: CInt
eventWd = Word8 -> CInt
forall a b. (Integral a, Num b) => a -> b
fromIntegral Word8
ewd
        , eventFlags :: Word32
eventFlags = Word32
eflags
        , eventCookie :: Word32
eventCookie = Word32
cookie
        , eventRelPath :: Maybe PosixPath
eventRelPath = PathRep -> Maybe PosixPath
getRepSub PathRep
prep1
        , eventMap :: IntMap PathRep
eventMap = IntMap PathRep
wdm
        }

    where

    readHeader :: Ptr Word8 -> p -> IO (Word8, b, c, d)
readHeader (Ptr Word8
ptr :: Ptr Word8) p
_ = do
        let len :: Key
len = CInt -> Key
forall a. Storable a => a -> Key
sizeOf (CInt
forall a. HasCallStack => a
undefined :: CInt)
        Word8
ewd <- Ptr Word8 -> IO Word8
forall a. Storable a => Ptr a -> IO a
peek Ptr Word8
ptr
        b
eflags <- Ptr Word8 -> Key -> IO b
forall b. Ptr b -> Key -> IO b
forall a b. Storable a => Ptr b -> Key -> IO a
peekByteOff Ptr Word8
ptr Key
len
        c
cookie <- Ptr Word8 -> Key -> IO c
forall b. Ptr b -> Key -> IO c
forall a b. Storable a => Ptr b -> Key -> IO a
peekByteOff Ptr Word8
ptr (Key
len Key -> Key -> Key
forall a. Num a => a -> a -> a
+ Key
4)
        Word32
pathLen :: Word32 <- Ptr Word8 -> Key -> IO Word32
forall b. Ptr b -> Key -> IO Word32
forall a b. Storable a => Ptr b -> Key -> IO a
peekByteOff Ptr Word8
ptr (Key
len Key -> Key -> Key
forall a. Num a => a -> a -> a
+ Key
8)
        (Word8, b, c, d) -> IO (Word8, b, c, d)
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return (Word8
ewd, b
eflags, c
cookie, Word32 -> d
forall a b. (Integral a, Num b) => a -> b
fromIntegral Word32
pathLen)

watchToStream :: Config -> Watch -> Stream IO Event
watchToStream :: Config -> Watch -> Stream IO Event
watchToStream Config
cfg wt :: Watch
wt@(Watch Handle
handle IORef (IntMap PathRep)
_) = do
    -- Do not use too small a buffer. As per inotify man page:
    --
    -- The behavior when the buffer given to read(2) is too small to return
    -- information about the next event depends on the kernel version: in
    -- kernels before 2.6.21, read(2) returns 0; since kernel 2.6.21, read(2)
    -- fails with the error EINVAL.  Specifying a buffer of size
    --
    --          sizeof(struct inotify_event) + NAME_MAX + 1
    --
    -- will be sufficient to read at least one event.
    Stream IO (Either ParseError Event) -> Stream IO Event
forall (m :: * -> *) a b.
Monad m =>
Stream m (Either a b) -> Stream m b
S.catRights (Stream IO (Either ParseError Event) -> Stream IO Event)
-> Stream IO (Either ParseError Event) -> Stream IO Event
forall a b. (a -> b) -> a -> b
$ Parser Word8 IO Event
-> Stream IO Word8 -> Stream IO (Either ParseError Event)
forall (m :: * -> *) a b.
Monad m =>
Parser a m b -> Stream m a -> Stream m (Either ParseError b)
S.parseMany (Config -> Watch -> Parser Word8 IO Event
readOneEvent Config
cfg Watch
wt) (Stream IO Word8 -> Stream IO (Either ParseError Event))
-> Stream IO Word8 -> Stream IO (Either ParseError Event)
forall a b. (a -> b) -> a -> b
$ Unfold IO Handle Word8 -> Handle -> Stream IO Word8
forall (m :: * -> *) a b.
Applicative m =>
Unfold m a b -> a -> Stream m b
S.unfold Unfold IO Handle Word8
forall (m :: * -> *). MonadIO m => Unfold m Handle Word8
FH.reader Handle
handle

-- XXX We should not go across the mount points of network file systems or file
-- systems that are known to not generate any events.
--
-- | Start monitoring a list of file system paths for file system events with
-- the supplied configuration operation over the 'defaultConfig'. The
-- paths could be files or directories. When recursive mode is set and the
-- path is a directory, the whole directory tree under it is watched
-- recursively. Monitoring starts from the current time onwards.
--
-- /Non-existing Paths:/ the API fails if a watch is started on a non-exsting
-- path.
--
-- /Performance:/ Note that recursive watch on a large directory tree could be
-- expensive. When starting a watch, the whole tree must be read and watches
-- are started on each directory in the tree. The initial time to start the
-- watch as well as the memory required is proportional to the number of
-- directories in the tree.
--
-- /Bugs:/ When new directories are created under the tree they are added to
-- the watch on receiving the directory create event. However, the creation of
-- a dir and adding a watch for it is not atomic.  The implementation takes
-- care of this and makes sure that watches are added for all directories.
-- However, In the mean time, the directory may have received more events which
-- may get lost.  Handling of any such lost events is yet to be implemented.
--
-- See the Linux __inotify__ man page for more details.
--
-- @
-- watchwith
--      ('setFollowSymLinks' True . 'setUnwatchMoved' False)
--      [Path.fromString "dir"]
-- @
--
-- /Pre-release/
--
watchWith :: (Config -> Config) -> NonEmpty Path -> Stream IO Event
watchWith :: (Config -> Config) -> NonEmpty PosixPath -> Stream IO Event
watchWith Config -> Config
f NonEmpty PosixPath
paths = IO Watch
-> (Watch -> IO ())
-> (Watch -> Stream IO Event)
-> Stream IO Event
forall (m :: * -> *) b c a.
(MonadIO m, MonadCatch m) =>
IO b -> (b -> IO c) -> (b -> Stream m a) -> Stream m a
S.bracketIO IO Watch
before Watch -> IO ()
after (Config -> Watch -> Stream IO Event
watchToStream Config
cfg)

    where

    cfg :: Config
cfg = Config -> Config
f Config
defaultConfig
    before :: IO Watch
before = Config -> NonEmpty PosixPath -> IO Watch
openWatch Config
cfg NonEmpty PosixPath
paths
    after :: Watch -> IO ()
after = Watch -> IO ()
closeWatch

-- | Same as 'watchWith' using 'defaultConfig' and recursive mode.
--
-- >>> watchRecursive = watchWith (setRecursiveMode True)
--
-- See 'watchWith' for pitfalls and bugs when using recursive watch on Linux.
--
-- /Pre-release/
--
watchRecursive :: NonEmpty Path -> Stream IO Event
watchRecursive :: NonEmpty PosixPath -> Stream IO Event
watchRecursive = (Config -> Config) -> NonEmpty PosixPath -> Stream IO Event
watchWith (Bool -> Config -> Config
setRecursiveMode Bool
True)

-- | Same as 'watchWith' using defaultConfig and non-recursive mode.
--
-- >>> watch = watchWith id
--
-- /Pre-release/
--
watch :: NonEmpty Path -> Stream IO Event
watch :: NonEmpty PosixPath -> Stream IO Event
watch = (Config -> Config) -> NonEmpty PosixPath -> Stream IO Event
watchWith Config -> Config
forall a. a -> a
id

-------------------------------------------------------------------------------
-- Examine event stream
-------------------------------------------------------------------------------

-- XXX Should we return a Maybe here instead of erroring out?
-- | Get the watch root corresponding to the 'Event'.
--
-- Note that if a path was moved after adding to the watch, this will give the
-- original path and not the new path after moving.
--
-- TBD: we can possibly update the watch root on a move self event.
--
-- /Pre-release/
--
getRoot :: Event -> Path
getRoot :: Event -> PosixPath
getRoot Event{Maybe PosixPath
Word32
CInt
IntMap PathRep
eventWd :: Event -> CInt
eventFlags :: Event -> Word32
eventCookie :: Event -> Word32
eventRelPath :: Event -> Maybe PosixPath
eventMap :: Event -> IntMap PathRep
eventWd :: CInt
eventFlags :: Word32
eventCookie :: Word32
eventRelPath :: Maybe PosixPath
eventMap :: IntMap PathRep
..} =
    if CInt
eventWd CInt -> CInt -> Bool
forall a. Ord a => a -> a -> Bool
>= CInt
1
    then
        case Key -> IntMap PathRep -> Maybe PathRep
forall a. Key -> IntMap a -> Maybe a
Map.lookup (CInt -> Key
forall a b. (Integral a, Num b) => a -> b
fromIntegral CInt
eventWd) IntMap PathRep
eventMap of
            Just PathRep
prep -> PathRep -> PosixPath
getRepRoot PathRep
prep
            Maybe PathRep
Nothing ->
                [Char] -> PosixPath
forall a. HasCallStack => [Char] -> a
error ([Char] -> PosixPath) -> [Char] -> PosixPath
forall a b. (a -> b) -> a -> b
$ [Char]
"Bug: getRoot: No path found corresponding to the "
                    [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ [Char]
"watch descriptor " [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ CInt -> [Char]
forall a. Show a => a -> [Char]
show CInt
eventWd
    else [Char] -> PosixPath
forall a. HasCallStack => [Char] -> a
error ([Char] -> PosixPath) -> [Char] -> PosixPath
forall a b. (a -> b) -> a -> b
$ [Char]
"getRoot: ewd = " [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ CInt -> [Char]
forall a. Show a => a -> [Char]
show CInt
eventWd

-- XXX should we use a Maybe here?
-- | Get the file system object path for which the event is generated, relative
-- to the watched root. The path is a "/" separated array of bytes.
--
-- /Pre-release/
--
getRelPath :: Event -> Maybe Path
getRelPath :: Event -> Maybe PosixPath
getRelPath Event{Maybe PosixPath
Word32
CInt
IntMap PathRep
eventWd :: Event -> CInt
eventFlags :: Event -> Word32
eventCookie :: Event -> Word32
eventRelPath :: Event -> Maybe PosixPath
eventMap :: Event -> IntMap PathRep
eventWd :: CInt
eventFlags :: Word32
eventCookie :: Word32
eventRelPath :: Maybe PosixPath
eventMap :: IntMap PathRep
..} = Maybe PosixPath
eventRelPath

-- | Get the absolute file system object path for which the event is generated.
--
-- When the watch root is a symlink, the absolute path returned is via the
-- original symlink and not through the resolved path.
--
-- /Pre-release/
--
getAbsPath :: Event -> Path
getAbsPath :: Event -> PosixPath
getAbsPath Event
ev =
    case Event -> Maybe PosixPath
getRelPath Event
ev of
        Just PosixPath
relPath -> PosixPath -> PosixPath -> PosixPath
Path.append (Event -> PosixPath
getRoot Event
ev) PosixPath
relPath
        Maybe PosixPath
Nothing -> Event -> PosixPath
getRoot Event
ev

-- XXX should we use a Maybe?
-- | Cookie is set when a rename occurs. The cookie value can be used to
-- connect the 'isMovedFrom' and 'isMovedTo' events, if both the events belong
-- to the same move operation then they will have the same cookie value.
--
-- /Pre-release/
--
getCookie :: Event -> Cookie
getCookie :: Event -> Cookie
getCookie Event{Maybe PosixPath
Word32
CInt
IntMap PathRep
eventWd :: Event -> CInt
eventFlags :: Event -> Word32
eventCookie :: Event -> Word32
eventRelPath :: Event -> Maybe PosixPath
eventMap :: Event -> IntMap PathRep
eventWd :: CInt
eventFlags :: Word32
eventCookie :: Word32
eventRelPath :: Maybe PosixPath
eventMap :: IntMap PathRep
..} = Word32 -> Cookie
Cookie Word32
eventCookie

-------------------------------------------------------------------------------
-- Event types
-------------------------------------------------------------------------------

getFlag :: Word32 -> Event -> Bool
getFlag :: Word32 -> Event -> Bool
getFlag Word32
mask Event{Maybe PosixPath
Word32
CInt
IntMap PathRep
eventWd :: Event -> CInt
eventFlags :: Event -> Word32
eventCookie :: Event -> Word32
eventRelPath :: Event -> Maybe PosixPath
eventMap :: Event -> IntMap PathRep
eventWd :: CInt
eventFlags :: Word32
eventCookie :: Word32
eventRelPath :: Maybe PosixPath
eventMap :: IntMap PathRep
..} = Word32
eventFlags Word32 -> Word32 -> Word32
forall a. Bits a => a -> a -> a
.&. Word32
mask Word32 -> Word32 -> Bool
forall a. Eq a => a -> a -> Bool
/= Word32
0

-------------------------------------------------------------------------------
-- Error events
-------------------------------------------------------------------------------

foreign import capi
    "sys/inotify.h value IN_Q_OVERFLOW" iN_Q_OVERFLOW :: Word32

-- XXX rename to isQOverflowed or hasOverflowed?
--
-- macOS overflow API is more specific, it tells which paths have lost the
-- events due to overflow.
--
-- | Event queue overflowed (WD is invalid for this event) and we may have lost
-- some events..  The user application must scan everything under the watched
-- paths to know the current state.
--
-- /Pre-release/
--
isEventsLost :: Event -> Bool
isEventsLost :: Event -> Bool
isEventsLost = Word32 -> Event -> Bool
getFlag Word32
iN_Q_OVERFLOW

-------------------------------------------------------------------------------
-- Events affecting the watched path only
-------------------------------------------------------------------------------

foreign import capi
    "sys/inotify.h value IN_IGNORED" iN_IGNORED :: Word32

-- Compare with isRootChanged on macOS. isRootChanged includes all these cases.
--
-- | A path was removed from the watch explicitly using 'removeFromWatch' or
-- automatically (file was deleted, or filesystem was unmounted).
--
-- Note that in recursive watch mode all the subdirectories are watch roots,
-- therefore, they will all generate this event.
--
-- /Occurs only for a watched path/
--
-- /Pre-release/
--
isRootUnwatched :: Event -> Bool
isRootUnwatched :: Event -> Bool
isRootUnwatched = Word32 -> Event -> Bool
getFlag Word32
iN_IGNORED

-- | Watched file/directory was itself deleted.  (This event also occurs if an
-- object is moved to another filesystem, since mv(1) in effect copies the file
-- to the other filesystem and then deletes it from the original filesystem.)
-- In addition, an 'isRootUnwatched' event will subsequently be generated
-- for the watch descriptor.
--
-- Note that in recursive watch mode all the subdirectories are watch roots,
-- therefore, they will all generate this event.
--
-- /Occurs only for a watched path/
--
-- /Pre-release/
--
isRootDeleted :: Event -> Bool
isRootDeleted :: Event -> Bool
isRootDeleted = Word32 -> Event -> Bool
getFlag Word32
iN_DELETE_SELF

-- | Watched file/directory was itself moved within the file system.
--
-- Note that in recursive watch mode all the subdirectories are watch roots,
-- therefore, they will all generate this event.
--
-- /Occurs only for a watched path/
--
-- /Pre-release/
--
isRootMoved :: Event -> Bool
isRootMoved :: Event -> Bool
isRootMoved = Word32 -> Event -> Bool
getFlag Word32
iN_MOVE_SELF

foreign import capi
    "sys/inotify.h value IN_UNMOUNT" iN_UNMOUNT :: Word32

-- | Filesystem containing watched object was unmounted.  In addition, an
-- 'isRootUnwatched' event will subsequently be generated for the watch
-- descriptor.
--
-- /Occurs only for a watched path/
--
-- /Pre-release/
--
isRootUnmounted :: Event -> Bool
isRootUnmounted :: Event -> Bool
isRootUnmounted = Word32 -> Event -> Bool
getFlag Word32
iN_UNMOUNT

-- | Determine whether the event indicates a change of path of the monitored
-- object itself. Note that the object may become unreachable or deleted after
-- a change of path.
--
-- /Occurs only for a watched path/
--
-- /Pre-release/
--
isRootPathEvent :: Event -> Bool
isRootPathEvent :: Event -> Bool
isRootPathEvent = Word32 -> Event -> Bool
getFlag (Word32
iN_DELETE_SELF Word32 -> Word32 -> Word32
forall a. Bits a => a -> a -> a
.|. Word32
iN_MOVE_SELF Word32 -> Word32 -> Word32
forall a. Bits a => a -> a -> a
.|. Word32
iN_UNMOUNT)

-------------------------------------------------------------------------------
-- Metadata change Events
-------------------------------------------------------------------------------

-- macOS has multiple APIs for metadata change for different metadata.
--
-- | Determine whether the event indicates inode metadata change for an object
-- contained within the monitored path.
--
-- Metadata change may include, permissions (e.g., chmod(2)), timestamps
-- (e.g., utimensat(2)), extended attributes (setxattr(2)), link count (since
-- Linux 2.6.25; e.g., for the target of link(2) and for unlink(2)), and
-- user/group ID (e.g., chown(2)).
--
-- /Can occur for watched path or a file inside it/
--
-- /Pre-release/
--
isAttrsModified :: Event -> Bool
isAttrsModified :: Event -> Bool
isAttrsModified = Word32 -> Event -> Bool
getFlag Word32
iN_ATTRIB

-------------------------------------------------------------------------------
-- Access
-------------------------------------------------------------------------------

-- | File was accessed (e.g. read, execve).
--
-- /Occurs only for a file inside the watched directory/
--
-- /Pre-release/
--
isAccessed :: Event -> Bool
isAccessed :: Event -> Bool
isAccessed = Word32 -> Event -> Bool
getFlag Word32
iN_ACCESS

-- | File or directory was opened.
--
-- /Occurs only for a file inside the watched directory/
--
-- /Pre-release/
--
isOpened :: Event -> Bool
isOpened :: Event -> Bool
isOpened = Word32 -> Event -> Bool
getFlag Word32
iN_OPEN

-- | File opened for writing was closed.
--
-- /Occurs only for a file inside the watched directory/
--
-- /Pre-release/
--
isWriteClosed :: Event -> Bool
isWriteClosed :: Event -> Bool
isWriteClosed = Word32 -> Event -> Bool
getFlag Word32
iN_CLOSE_WRITE

-- XXX what if it was opened for append? Does NOWRITE mean all cases where the
-- mode was not write? A dir open comes in this category?
--
-- | File or directory opened for read but not write was closed.
--
-- /Can occur for watched path or a file inside it/
--
-- /Pre-release/
--
isNonWriteClosed :: Event -> Bool
isNonWriteClosed :: Event -> Bool
isNonWriteClosed = Word32 -> Event -> Bool
getFlag Word32
iN_CLOSE_NOWRITE

-------------------------------------------------------------------------------
-- CRUD Events
-------------------------------------------------------------------------------

-- On macOS this is not generated on hard linking but on Linux it is.
--
-- | File/directory created in watched directory (e.g., open(2) O_CREAT,
-- mkdir(2), link(2), symlink(2), bind(2) on a UNIX domain socket).
--
-- /Occurs only for an object inside the watched directory/
--
-- /Pre-release/
--
isCreated :: Event -> Bool
isCreated :: Event -> Bool
isCreated = Word32 -> Event -> Bool
getFlag Word32
iN_CREATE

-- | File/directory deleted from watched directory.
--
-- /Occurs only for an object inside the watched directory/
--
-- /Pre-release/
--
isDeleted :: Event -> Bool
isDeleted :: Event -> Bool
isDeleted = Word32 -> Event -> Bool
getFlag Word32
iN_DELETE

-- XXX what if an object is moved in from outside or moved out of the monitored
-- dir?
--
-- | Generated for the original path when an object is moved from under a
-- monitored directory.
--
-- /Occurs only for an object inside the watched directory/
--
-- /Pre-release/
--
isMovedFrom :: Event -> Bool
isMovedFrom :: Event -> Bool
isMovedFrom = Word32 -> Event -> Bool
getFlag Word32
iN_MOVED_FROM

-- | Generated for the new path when an object is moved under a monitored
-- directory.
--
-- /Occurs only for an object inside the watched directory/
--
-- /Pre-release/
--
isMovedTo :: Event -> Bool
isMovedTo :: Event -> Bool
isMovedTo = Word32 -> Event -> Bool
getFlag Word32
iN_MOVED_TO

-- | Generated for a path that is moved from or moved to the monitored
-- directory.
--
-- >>> isMoved ev = isMovedFrom ev || isMovedTo ev
--
-- /Occurs only for an object inside the watched directory/
--
-- /Pre-release/
--
isMoved :: Event -> Bool
isMoved :: Event -> Bool
isMoved Event
ev = Event -> Bool
isMovedFrom Event
ev Bool -> Bool -> Bool
|| Event -> Bool
isMovedTo Event
ev

-- | Determine whether the event indicates modification of an object within the
-- monitored path. This event is generated only for files and not directories.
--
-- /Occurs only for an object inside the watched directory/
--
-- /Pre-release/
--
isModified :: Event -> Bool
isModified :: Event -> Bool
isModified = Word32 -> Event -> Bool
getFlag Word32
iN_MODIFY

-------------------------------------------------------------------------------
-- Information about path type (applicable only when 'setFileEvents' is 'True')
-------------------------------------------------------------------------------

foreign import capi
    "sys/inotify.h value IN_ISDIR" iN_ISDIR :: Word32

-- | Determine whether the event is for a directory path.
--
-- /Pre-release/
--
isDir :: Event -> Bool
isDir :: Event -> Bool
isDir = Word32 -> Event -> Bool
getFlag Word32
iN_ISDIR

-------------------------------------------------------------------------------
-- Debugging
-------------------------------------------------------------------------------

-- | Convert an 'Event' record to a String representation.
showEvent :: Event -> String
showEvent :: Event -> [Char]
showEvent ev :: Event
ev@Event{Maybe PosixPath
Word32
CInt
IntMap PathRep
eventWd :: Event -> CInt
eventFlags :: Event -> Word32
eventCookie :: Event -> Word32
eventRelPath :: Event -> Maybe PosixPath
eventMap :: Event -> IntMap PathRep
eventWd :: CInt
eventFlags :: Word32
eventCookie :: Word32
eventRelPath :: Maybe PosixPath
eventMap :: IntMap PathRep
..} =
       [Char]
"--------------------------"
    [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ [Char]
"\nWd = " [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ CInt -> [Char]
forall a. Show a => a -> [Char]
show CInt
eventWd
    [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ [Char]
"\nRoot = " [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ ShowS
forall a. Show a => a -> [Char]
show (PosixPath -> [Char]
forall a. IsPath PosixPath a => a -> [Char]
Path.toString (PosixPath -> [Char]) -> PosixPath -> [Char]
forall a b. (a -> b) -> a -> b
$ Event -> PosixPath
getRoot Event
ev)
    [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ [Char]
"\nPath = " [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ [Char] -> (PosixPath -> [Char]) -> Maybe PosixPath -> [Char]
forall b a. b -> (a -> b) -> Maybe a -> b
maybe [Char]
"" (ShowS
forall a. Show a => a -> [Char]
show ShowS -> (PosixPath -> [Char]) -> PosixPath -> [Char]
forall b c a. (b -> c) -> (a -> b) -> a -> c
. PosixPath -> [Char]
forall a. IsPath PosixPath a => a -> [Char]
Path.toString) (Event -> Maybe PosixPath
getRelPath Event
ev)
    [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ [Char]
"\nCookie = " [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ Cookie -> [Char]
forall a. Show a => a -> [Char]
show (Event -> Cookie
getCookie Event
ev)
    [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ [Char]
"\nFlags " [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ Word32 -> [Char]
forall a. Show a => a -> [Char]
show Word32
eventFlags

    [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ (Event -> Bool) -> ShowS
showev Event -> Bool
isEventsLost [Char]
"Overflow"

    [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ (Event -> Bool) -> ShowS
showev Event -> Bool
isRootUnwatched [Char]
"RootUnwatched"
    [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ (Event -> Bool) -> ShowS
showev Event -> Bool
isRootDeleted [Char]
"RootDeleted"
    [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ (Event -> Bool) -> ShowS
showev Event -> Bool
isRootMoved [Char]
"RootMoved"
    [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ (Event -> Bool) -> ShowS
showev Event -> Bool
isRootUnmounted [Char]
"RootUnmounted"

    [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ (Event -> Bool) -> ShowS
showev Event -> Bool
isAttrsModified [Char]
"AttrsModified"

    [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ (Event -> Bool) -> ShowS
showev Event -> Bool
isAccessed [Char]
"Accessed"
    [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ (Event -> Bool) -> ShowS
showev Event -> Bool
isOpened [Char]
"Opened"
    [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ (Event -> Bool) -> ShowS
showev Event -> Bool
isWriteClosed [Char]
"WriteClosed"
    [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ (Event -> Bool) -> ShowS
showev Event -> Bool
isNonWriteClosed [Char]
"NonWriteClosed"

    [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ (Event -> Bool) -> ShowS
showev Event -> Bool
isCreated [Char]
"Created"
    [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ (Event -> Bool) -> ShowS
showev Event -> Bool
isDeleted [Char]
"Deleted"
    [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ (Event -> Bool) -> ShowS
showev Event -> Bool
isModified [Char]
"Modified"
    [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ (Event -> Bool) -> ShowS
showev Event -> Bool
isMovedFrom [Char]
"MovedFrom"
    [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ (Event -> Bool) -> ShowS
showev Event -> Bool
isMovedTo [Char]
"MovedTo"

    [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ (Event -> Bool) -> ShowS
showev Event -> Bool
isDir [Char]
"Dir"
    [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ [Char]
"\n"

        where showev :: (Event -> Bool) -> ShowS
showev Event -> Bool
f [Char]
str = if Event -> Bool
f Event
ev then [Char]
"\n" [Char] -> ShowS
forall a. [a] -> [a] -> [a]
++ [Char]
str else [Char]
""
#else
#warning "Disabling module Streamly.Internal.FS.Event.Linux. Does not support kernels older than 2.6.36."
module Streamly.Internal.FS.Event.Linux () where
#endif