hpath/hpath-io/src/HPath/IO.hs

866 lines
26 KiB
Haskell

-- |
-- Module : HPath.IO
-- Copyright : © 2016 Julian Ospald
-- License : BSD3
--
-- Maintainer : Julian Ospald <hasufell@posteo.de>
-- Stability : experimental
-- Portability : portable
--
-- This module provides high-level IO related file operations like
-- copy, delete, move and so on. It only operates on /Path x/ which
-- guarantees us well-typed paths. This is a thin wrapper over
-- System.Posix.RawFilePath.Directory in 'hpath-directory'. It's
-- encouraged to use this module.
--
-- Some of these operations are due to their nature __not atomic__, which
-- means they may do multiple syscalls which form one context. Some
-- of them also have to examine the filetypes explicitly before the
-- syscalls, so a reasonable decision can be made. That means
-- the result is undefined if another process changes that context
-- while the non-atomic operation is still happening. However, where
-- possible, as few syscalls as possible are used and the underlying
-- exception handling is kept.
--
-- Note: `BlockDevice`, `CharacterDevice`, `NamedPipe` and `Socket`
-- are ignored by some of the more high-level functions (like `easyCopy`).
-- For other functions (like `copyFile`), the behavior on these file types is
-- unreliable/unsafe. Check the documentation of those functions for details.
{-# LANGUAGE FlexibleContexts #-} -- streamly
{-# LANGUAGE PackageImports #-}
module HPath.IO
(
-- * Types
FileType(..)
, RecursiveErrorMode(..)
, CopyMode(..)
-- * File copying
, copyDirRecursive
, recreateSymlink
, copyFile
, easyCopy
-- * File deletion
, deleteFile
, deleteDir
, deleteDirRecursive
, easyDelete
-- * File opening
, openFile
, executeFile
-- * File creation
, createRegularFile
, createDir
, createDirIfMissing
, createDirRecursive
, createSymlink
-- * File renaming/moving
, renameFile
, moveFile
-- * File reading
, readFile
, readFileStream
-- * File writing
, writeFile
, writeFileL
, appendFile
-- * File permissions
, RD.newFilePerms
, RD.newDirPerms
-- * File checks
, doesExist
, doesFileExist
, doesDirectoryExist
, isReadable
, isWritable
, isExecutable
, canOpenDirectory
-- * File times
, getModificationTime
, setModificationTime
, setModificationTimeHiRes
-- * Directory reading
, getDirsFiles
, getDirsFiles'
, getDirsFilesStream
-- * Filetype operations
, getFileType
-- * Others
, canonicalizePath
, toAbs
, withRawFilePath
, withHandle
, module System.Posix.RawFilePath.Directory.Errors
)
where
import Control.Exception.Safe ( MonadMask
, MonadCatch
, bracketOnError
, finally
)
import Control.Monad.Catch ( MonadThrow(..) )
import Data.ByteString ( ByteString )
import Data.Traversable ( for )
import qualified Data.ByteString.Lazy as L
import Data.Time.Clock
import Data.Time.Clock.POSIX ( POSIXTime )
import HPath
import Prelude hiding ( appendFile
, readFile
, writeFile
)
import Streamly
import qualified System.IO as SIO
import System.Posix.Directory.ByteString
( getWorkingDirectory )
import qualified "unix" System.Posix.IO.ByteString
as SPI
import System.Posix.FD ( openFd )
import System.Posix.RawFilePath.Directory.Errors
import System.Posix.Types ( FileMode
, ProcessID
, EpochTime
)
import qualified System.Posix.RawFilePath.Directory
as RD
import System.Posix.RawFilePath.Directory
( FileType
, RecursiveErrorMode
, CopyMode
)
--------------------
--[ File Copying ]--
--------------------
-- |Copies the contents of a directory recursively to the given destination, while preserving permissions.
-- Does not follow symbolic links. This behaves more or less like
-- the following, without descending into the destination if it
-- already exists:
--
-- @
-- cp -a \/source\/dir \/destination\/somedir
-- @
--
-- For directory contents, this will ignore any file type that is not
-- `RegularFile`, `SymbolicLink` or `Directory`.
--
-- For `Overwrite` copy mode this does not prune destination directory
-- contents, so the destination might contain more files than the source after
-- the operation has completed. Permissions of existing directories are
-- fixed.
--
-- Safety/reliability concerns:
--
-- * not atomic
-- * examines filetypes explicitly
-- * an explicit check `throwDestinationInSource` is carried out for the
-- top directory for basic sanity, because otherwise we might end up
-- with an infinite copy loop... however, this operation is not
-- carried out recursively (because it's slow)
--
-- Throws:
--
-- - `NoSuchThing` if source directory does not exist
-- - `PermissionDenied` if source directory can't be opened
-- - `SameFile` if source and destination are the same file
-- (`HPathIOException`)
-- - `DestinationInSource` if destination is contained in source
-- (`HPathIOException`)
--
-- Throws in `FailEarly` RecursiveErrorMode only:
--
-- - `PermissionDenied` if output directory is not writable
-- - `InvalidArgument` if source directory is wrong type (symlink)
-- - `InappropriateType` if source directory is wrong type (regular file)
--
-- Throws in `CollectFailures` RecursiveErrorMode only:
--
-- - `RecursiveFailure` if any of the recursive operations that are not
-- part of the top-directory sanity-checks fail (`HPathIOException`)
--
-- Throws in `Strict` CopyMode only:
--
-- - `AlreadyExists` if destination already exists
--
-- Note: may call `getcwd` (only if destination is a relative path)
copyDirRecursive :: Path b1 -- ^ source dir
-> Path b2 -- ^ destination (parent dirs
-- are not automatically created)
-> CopyMode
-> RecursiveErrorMode
-> IO ()
copyDirRecursive (Path fromp) (Path destdirp) cm rm =
RD.copyDirRecursive fromp destdirp cm rm
-- |Recreate a symlink.
--
-- In `Overwrite` copy mode only files and empty directories are deleted.
--
-- Safety/reliability concerns:
--
-- * `Overwrite` mode is inherently non-atomic
--
-- Throws:
--
-- - `InvalidArgument` if source file is wrong type (not a symlink)
-- - `PermissionDenied` if output directory cannot be written to
-- - `PermissionDenied` if source directory cannot be opened
-- - `SameFile` if source and destination are the same file
-- (`HPathIOException`)
--
--
-- Throws in `Strict` mode only:
--
-- - `AlreadyExists` if destination already exists
--
-- Throws in `Overwrite` mode only:
--
-- - `UnsatisfiedConstraints` if destination file is non-empty directory
--
-- Notes:
--
-- - calls `symlink`
-- - calls `getcwd` in Overwrite mode (if destination is a relative path)
recreateSymlink :: Path b1 -- ^ the old symlink file
-> Path b2 -- ^ destination file
-> CopyMode
-> IO ()
recreateSymlink (Path symsourceBS) (Path newsymBS) cm =
RD.recreateSymlink symsourceBS newsymBS cm
-- |Copies the given regular file to the given destination.
-- Neither follows symbolic links, nor accepts them.
-- For "copying" symbolic links, use `recreateSymlink` instead.
--
-- Note that this is still sort of a low-level function and doesn't
-- examine file types. For a more high-level version, use `easyCopy`
-- instead.
--
-- In `Overwrite` copy mode only overwrites actual files, not directories.
-- In `Strict` mode the destination file must not exist.
--
-- Safety/reliability concerns:
--
-- * `Overwrite` mode is not atomic
-- * when used on `CharacterDevice`, reads the "contents" and copies
-- them to a regular file, which might take indefinitely
-- * when used on `BlockDevice`, may either read the "contents"
-- and copy them to a regular file (potentially hanging indefinitely)
-- or may create a regular empty destination file
-- * when used on `NamedPipe`, will hang indefinitely
--
-- Throws:
--
-- - `NoSuchThing` if source file does not exist
-- - `NoSuchThing` if source file is a a `Socket`
-- - `PermissionDenied` if output directory is not writable
-- - `PermissionDenied` if source directory can't be opened
-- - `InvalidArgument` if source file is wrong type (symlink or directory)
-- - `SameFile` if source and destination are the same file
-- (`HPathIOException`)
--
-- Throws in `Strict` mode only:
--
-- - `AlreadyExists` if destination already exists
--
-- Notes:
--
-- - may call `getcwd` in Overwrite mode (if destination is a relative path)
copyFile :: Path b1 -- ^ source file
-> Path b2 -- ^ destination file
-> CopyMode
-> IO ()
copyFile (Path from) (Path to) cm = RD.copyFile from to cm
-- |Copies a regular file, directory or symbolic link. In case of a
-- symbolic link it is just recreated, even if it points to a directory.
-- Any other file type is ignored.
--
-- Safety/reliability concerns:
--
-- * examines filetypes explicitly
-- * calls `copyDirRecursive` for directories
--
-- Note: may call `getcwd` in Overwrite mode (if destination is a relative path)
easyCopy :: Path b1 -> Path b2 -> CopyMode -> RecursiveErrorMode -> IO ()
easyCopy (Path from) (Path to) cm rm = RD.easyCopy from to cm rm
---------------------
--[ File Deletion ]--
---------------------
-- |Deletes the given file. Raises `eISDIR`
-- if run on a directory. Does not follow symbolic links.
--
-- Throws:
--
-- - `InappropriateType` for wrong file type (directory)
-- - `NoSuchThing` if the file does not exist
-- - `PermissionDenied` if the directory cannot be read
deleteFile :: Path b -> IO ()
deleteFile (Path p) = RD.deleteFile p
-- |Deletes the given directory, which must be empty, never symlinks.
--
-- Throws:
--
-- - `InappropriateType` for wrong file type (symlink to directory)
-- - `InappropriateType` for wrong file type (regular file)
-- - `NoSuchThing` if directory does not exist
-- - `UnsatisfiedConstraints` if directory is not empty
-- - `PermissionDenied` if we can't open or write to parent directory
--
-- Notes: calls `rmdir`
deleteDir :: Path b -> IO ()
deleteDir (Path p) = RD.deleteDir p
-- |Deletes the given directory recursively. Does not follow symbolic
-- links. Tries `deleteDir` first before attemtping a recursive
-- deletion.
--
-- On directory contents this behaves like `easyDelete`
-- and thus will ignore any file type that is not `RegularFile`,
-- `SymbolicLink` or `Directory`.
--
-- Safety/reliability concerns:
--
-- * not atomic
-- * examines filetypes explicitly
--
-- Throws:
--
-- - `InappropriateType` for wrong file type (symlink to directory)
-- - `InappropriateType` for wrong file type (regular file)
-- - `NoSuchThing` if directory does not exist
-- - `PermissionDenied` if we can't open or write to parent directory
deleteDirRecursive :: Path b -> IO ()
deleteDirRecursive (Path p) = RD.deleteDirRecursive p
-- |Deletes a file, directory or symlink.
-- In case of directory, performs recursive deletion. In case of
-- a symlink, the symlink file is deleted.
-- Any other file type is ignored.
--
-- Safety/reliability concerns:
--
-- * examines filetypes explicitly
-- * calls `deleteDirRecursive` for directories
easyDelete :: Path b -> IO ()
easyDelete (Path p) = RD.easyDelete p
--------------------
--[ File Opening ]--
--------------------
-- |Opens a file appropriately by invoking xdg-open. The file type
-- is not checked. This forks a process.
openFile :: Path b -> IO ProcessID
openFile (Path fp) = RD.openFile fp
-- |Executes a program with the given arguments. This forks a process.
executeFile :: Path b -- ^ program
-> [ByteString] -- ^ arguments
-> IO ProcessID
executeFile (Path fp) args = RD.executeFile fp args
---------------------
--[ File Creation ]--
---------------------
-- |Create an empty regular file at the given directory with the given
-- filename.
--
-- Throws:
--
-- - `PermissionDenied` if output directory cannot be written to
-- - `AlreadyExists` if destination already exists
-- - `NoSuchThing` if any of the parent components of the path
-- do not exist
createRegularFile :: FileMode -> Path b -> IO ()
createRegularFile fm (Path destBS) = RD.createRegularFile fm destBS
-- |Create an empty directory at the given directory with the given filename.
--
-- Throws:
--
-- - `PermissionDenied` if output directory cannot be written to
-- - `AlreadyExists` if destination already exists
-- - `NoSuchThing` if any of the parent components of the path
-- do not exist
createDir :: FileMode -> Path b -> IO ()
createDir fm (Path destBS) = RD.createDir fm destBS
-- |Create an empty directory at the given directory with the given filename.
--
-- Throws:
--
-- - `PermissionDenied` if output directory cannot be written to
-- - `NoSuchThing` if any of the parent components of the path
-- do not exist
createDirIfMissing :: FileMode -> Path b -> IO ()
createDirIfMissing fm (Path destBS) = RD.createDirIfMissing fm destBS
-- |Create an empty directory at the given directory with the given filename.
-- All parent directories are created with the same filemode. This
-- basically behaves like:
--
-- @
-- mkdir -p \/some\/dir
-- @
--
-- Safety/reliability concerns:
--
-- * not atomic
--
-- Throws:
--
-- - `PermissionDenied` if any part of the path components do not
-- exist and cannot be written to
-- - `AlreadyExists` if destination already exists and
-- is *not* a directory
--
-- Note: calls `getcwd` if the input path is a relative path
createDirRecursive :: FileMode -> Path b -> IO ()
createDirRecursive fm (Path p) = RD.createDirRecursive fm p
-- |Create a symlink.
--
-- Throws:
--
-- - `PermissionDenied` if output directory cannot be written to
-- - `AlreadyExists` if destination file already exists
-- - `NoSuchThing` if any of the parent components of the path
-- do not exist
--
-- Note: calls `symlink`
createSymlink :: Path b -- ^ destination file
-> ByteString -- ^ path the symlink points to
-> IO ()
createSymlink (Path destBS) sympoint = RD.createSymlink destBS sympoint
----------------------------
--[ File Renaming/Moving ]--
----------------------------
-- |Rename a given file with the provided filename. Destination and source
-- must be on the same device, otherwise `eXDEV` will be raised.
--
-- Does not follow symbolic links, but renames the symbolic link file.
--
-- Safety/reliability concerns:
--
-- * has a separate set of exception handling, apart from the syscall
--
-- Throws:
--
-- - `NoSuchThing` if source file does not exist
-- - `PermissionDenied` if output directory cannot be written to
-- - `PermissionDenied` if source directory cannot be opened
-- - `UnsupportedOperation` if source and destination are on different
-- devices
-- - `AlreadyExists` if destination already exists
-- - `SameFile` if destination and source are the same file
-- (`HPathIOException`)
--
-- Note: calls `rename` (but does not allow to rename over existing files)
renameFile :: Path b1 -> Path b2 -> IO ()
renameFile (Path from) (Path to) = RD.renameFile from to
-- |Move a file. This also works across devices by copy-delete fallback.
-- And also works on directories.
--
-- Does not follow symbolic links, but renames the symbolic link file.
--
--
-- Safety/reliability concerns:
--
-- * `Overwrite` mode is not atomic
-- * copy-delete fallback is inherently non-atomic
-- * since this function calls `easyCopy` and `easyDelete` as a fallback
-- to `renameFile`, file types that are not `RegularFile`, `SymbolicLink`
-- or `Directory` may be ignored
-- * for `Overwrite` mode, the destination will be deleted (not recursively)
-- before moving
--
-- Throws:
--
-- - `NoSuchThing` if source file does not exist
-- - `PermissionDenied` if output directory cannot be written to
-- - `PermissionDenied` if source directory cannot be opened
-- - `SameFile` if destination and source are the same file
-- (`HPathIOException`)
--
-- Throws in `Strict` mode only:
--
-- - `AlreadyExists` if destination already exists
--
-- Notes:
--
-- - calls `rename` (but does not allow to rename over existing files)
-- - calls `getcwd` in Overwrite mode if destination is a relative path
moveFile :: Path b1 -- ^ file to move
-> Path b2 -- ^ destination
-> CopyMode
-> IO ()
moveFile (Path from) (Path to) cm = RD.moveFile from to cm
--------------------
--[ File Reading ]--
--------------------
-- |Read the given file *at once* into memory as a lazy ByteString.
-- Symbolic links are followed, no sanity checks on file size
-- or file type. File must exist. Uses Builders under the hood
-- (hence lazy ByteString).
--
-- Safety/reliability concerns:
--
-- * the whole file is read into memory, this doesn't read lazily
--
-- Throws:
--
-- - `InappropriateType` if file is not a regular file or a symlink
-- - `PermissionDenied` if we cannot read the file or the directory
-- containting it
-- - `NoSuchThing` if the file does not exist
readFile :: Path b -> IO L.ByteString
readFile (Path path) = RD.readFile path
-- | Open the given file as a filestream. Once the filestream is
-- exits, the filehandle is cleaned up.
--
-- Throws:
--
-- - `InappropriateType` if file is not a regular file or a symlink
-- - `PermissionDenied` if we cannot read the file or the directory
-- containting it
-- - `NoSuchThing` if the file does not exist
readFileStream :: Path b -> IO (SerialT IO ByteString)
readFileStream (Path fp) = RD.readFileStream fp
--------------------
--[ File Writing ]--
--------------------
-- |Write a given ByteString to a file, truncating the file beforehand.
-- Follows symlinks.
--
-- Throws:
--
-- - `InappropriateType` if file is not a regular file or a symlink
-- - `PermissionDenied` if we cannot read the file or the directory
-- containting it
-- - `NoSuchThing` if the file does not exist
writeFile :: Path b
-> Maybe FileMode -- ^ if Nothing, file must exist
-> ByteString
-> IO ()
writeFile (Path fp) fmode bs = RD.writeFile fp fmode bs
-- |Write a given lazy ByteString to a file, truncating the file beforehand.
-- Follows symlinks.
--
-- Throws:
--
-- - `InappropriateType` if file is not a regular file or a symlink
-- - `PermissionDenied` if we cannot read the file or the directory
-- containting it
-- - `NoSuchThing` if the file does not exist
--
-- Note: uses streamly under the hood
writeFileL :: Path b
-> Maybe FileMode -- ^ if Nothing, file must exist
-> L.ByteString
-> IO ()
writeFileL (Path fp) fmode lbs = RD.writeFileL fp fmode lbs
-- |Append a given ByteString to a file.
-- The file must exist. Follows symlinks.
--
-- Throws:
--
-- - `InappropriateType` if file is not a regular file or a symlink
-- - `PermissionDenied` if we cannot read the file or the directory
-- containting it
-- - `NoSuchThing` if the file does not exist
appendFile :: Path b -> ByteString -> IO ()
appendFile (Path fp) bs = RD.appendFile fp bs
-------------------
--[ File checks ]--
-------------------
-- |Checks if the given file exists.
-- Does not follow symlinks.
--
-- Only eNOENT is catched (and returns False).
doesExist :: Path b -> IO Bool
doesExist (Path bs) = RD.doesExist bs
-- |Checks if the given file exists and is not a directory.
-- Does not follow symlinks.
--
-- Only eNOENT is catched (and returns False).
doesFileExist :: Path b -> IO Bool
doesFileExist (Path bs) = RD.doesFileExist bs
-- |Checks if the given file exists and is a directory.
-- Does not follow symlinks.
--
-- Only eNOENT is catched (and returns False).
doesDirectoryExist :: Path b -> IO Bool
doesDirectoryExist (Path bs) = RD.doesDirectoryExist bs
-- |Checks whether a file or folder is readable.
--
-- Only eACCES, eROFS, eTXTBSY, ePERM are catched (and return False).
--
-- Throws:
--
-- - `NoSuchThing` if the file does not exist
isReadable :: Path b -> IO Bool
isReadable (Path bs) = RD.isReadable bs
-- |Checks whether a file or folder is writable.
--
-- Only eACCES, eROFS, eTXTBSY, ePERM are catched (and return False).
--
-- Throws:
--
-- - `NoSuchThing` if the file does not exist
isWritable :: Path b -> IO Bool
isWritable (Path bs) = RD.isWritable bs
-- |Checks whether a file or folder is executable.
--
-- Only eACCES, eROFS, eTXTBSY, ePERM are catched (and return False).
--
-- Throws:
--
-- - `NoSuchThing` if the file does not exist
isExecutable :: Path b -> IO Bool
isExecutable (Path bs) = RD.isExecutable bs
-- |Checks whether the directory at the given path exists and can be
-- opened. This invokes `openDirStream` which follows symlinks.
canOpenDirectory :: Path b -> IO Bool
canOpenDirectory (Path bs) = RD.canOpenDirectory bs
------------------
--[ File times ]--
------------------
getModificationTime :: Path b -> IO UTCTime
getModificationTime (Path bs) = RD.getModificationTime bs
setModificationTime :: Path b -> EpochTime -> IO ()
setModificationTime (Path bs) t = RD.setModificationTime bs t
setModificationTimeHiRes :: Path b -> POSIXTime -> IO ()
setModificationTimeHiRes (Path bs) t = RD.setModificationTimeHiRes bs t
-------------------------
--[ Directory reading ]--
-------------------------
-- |Gets all filenames of the given directory. This excludes "." and "..".
-- This version does not follow symbolic links.
--
-- The contents are not sorted and there is no guarantee on the ordering.
--
-- Throws:
--
-- - `NoSuchThing` if directory does not exist
-- - `InappropriateType` if file type is wrong (file)
-- - `InappropriateType` if file type is wrong (symlink to file)
-- - `InappropriateType` if file type is wrong (symlink to dir)
-- - `PermissionDenied` if directory cannot be opened
-- - `PathParseException` if a filename could not be parsed (should never happen)
getDirsFiles :: Path b -- ^ dir to read
-> IO [Path b]
getDirsFiles p = do
contents <- getDirsFiles' p
pure $ fmap (p </>) contents
-- | Like 'getDirsFiles', but returns the filename only, instead
-- of prepending the base path.
getDirsFiles' :: Path b -- ^ dir to read
-> IO [Path Rel]
getDirsFiles' (Path fp) = do
rawContents <- RD.getDirsFiles' fp
for rawContents $ \r -> parseRel r
-- | Like 'getDirsFiles'', except returning a Stream.
getDirsFilesStream :: (MonadCatch m, MonadAsync m, MonadMask m)
=> Path b
-> IO (SerialT m (Path Rel))
getDirsFilesStream (Path fp) = do
s <- RD.getDirsFilesStream fp
pure (s >>= parseRel)
---------------------------
--[ FileType operations ]--
---------------------------
-- |Get the file type of the file located at the given path. Does
-- not follow symbolic links.
--
-- Throws:
--
-- - `NoSuchThing` if the file does not exist
-- - `PermissionDenied` if any part of the path is not accessible
getFileType :: Path b -> IO FileType
getFileType (Path fp) = RD.getFileType fp
--------------
--[ Others ]--
--------------
-- |Applies `realpath` on the given path.
--
-- Throws:
--
-- - `NoSuchThing` if the file at the given path does not exist
-- - `NoSuchThing` if the symlink is broken
-- - `PathParseException` if realpath does not return an absolute path
canonicalizePath :: Path b -> IO (Path Abs)
canonicalizePath (Path l) = do
nl <- RD.canonicalizePath l
parseAbs nl
-- |Converts any path to an absolute path.
-- This is done in the following way:
--
-- - if the path is already an absolute one, just return it
-- - if it's a relative path, prepend the current directory to it
toAbs :: Path b -> IO (Path Abs)
toAbs (Path bs) = do
let mabs = parseAbs bs :: Maybe (Path Abs)
case mabs of
Just a -> return a
Nothing -> do
cwd <- getWorkingDirectory >>= parseAbs
r <- parseRel bs -- we know it must be relative now
return $ cwd </> r
-- | Helper function to use the Path library without
-- buying into the Path type too much. This uses 'parseAny'
-- under the hood and may throw `PathParseException`.
--
-- Throws:
--
-- - `PathParseException` if the bytestring could neither be parsed as
-- relative or absolute Path
withRawFilePath :: MonadThrow m
=> ByteString
-> (Either (Path Abs) (Path Rel) -> m b)
-> m b
withRawFilePath bs action = do
path <- parseAny bs
action path
-- | Convenience function to open the path as a handle.
--
-- If the file does not exist, it will be created with 'newFilePerms'.
--
-- Throws:
--
-- - `PathParseException` if the bytestring could neither be parsed as
-- relative or absolute Path
withHandle :: ByteString
-> SPI.OpenMode
-> ((SIO.Handle, Either (Path Abs) (Path Rel)) -> IO a)
-> IO a
withHandle bs mode action = do
path <- parseAny bs
handle <-
bracketOnError (openFd bs mode [] (Just RD.newFilePerms)) (SPI.closeFd)
$ SPI.fdToHandle
finally (action (handle, path)) (SIO.hClose handle)