Idris2/libs/base/System/Directory.idr

147 lines
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Idris

||| Directory access and handling.
module System.Directory
import System.Errno
import public System.File
import System.FFI
%default total
public export
DirPtr : Type
DirPtr = AnyPtr
||| Shorthand for referring to the C support library
|||
||| @ fn the function name to refer to in the C support library
supportC : (fn : String) -> String
supportC fn = "C:\{fn}, libidris2_support, idris_directory.h"
||| Shorthand for referring to the Node system support library
|||
||| @ fn the function name to refer to in the js/system_support.js file
supportNode : (fn : String) -> String
supportNode fn = "node:support:\{fn},support_system_directory"
ok : HasIO io => a -> io (Either FileError a)
ok x = pure (Right x)
%foreign supportC "idris2_currentDirectory"
"node:lambda:()=>process.cwd()"
prim__currentDir : PrimIO (Ptr String)
%foreign supportC "idris2_changeDir"
supportNode "changeDir"
prim__changeDir : String -> PrimIO Int
%foreign supportC "idris2_createDir"
supportNode "createDir"
prim__createDir : String -> PrimIO Int
%foreign supportC "idris2_openDir"
supportNode "openDir"
prim__openDir : String -> PrimIO DirPtr
%foreign supportC "idris2_closeDir"
supportNode "closeDir"
prim__closeDir : DirPtr -> PrimIO ()
%foreign supportC "idris2_removeDir"
supportNode "removeDir"
prim__removeDir : String -> PrimIO ()
%foreign supportC "idris2_nextDirEntry"
supportNode "dirEntry"
prim__dirEntry : DirPtr -> PrimIO (Ptr String)
||| Data structure for managing the pointer to a directory.
export
data Directory : Type where
MkDir : DirPtr -> Directory
||| Try to create a directory at the specified path.
export
createDir : HasIO io => String -> io (Either FileError ())
createDir dir
= do res <- primIO (prim__createDir dir)
if res == 0
then ok ()
else returnError
||| Change the current working directory to the specified path. Returns whether
||| the operation succeeded.
export
changeDir : HasIO io => String -> io Bool
changeDir dir
= do ok <- primIO (prim__changeDir dir)
pure (ok == 0)
||| Get the absolute path of the current working directory. Returns `Nothing` if
||| an error occurred.
export
currentDir : HasIO io => io (Maybe String)
currentDir
= do res <- primIO prim__currentDir
if prim__nullPtr res /= 0
then pure Nothing
else do let s = prim__getString res
free $ prim__forgetPtr res
pure (Just s)
||| Try to open the directory at the specified path.
export
openDir : HasIO io => String -> io (Either FileError Directory)
openDir d
= do res <- primIO (prim__openDir d)
if prim__nullAnyPtr res /= 0
then returnError
else ok (MkDir res)
||| Close the given `Directory`.
export
closeDir : HasIO io => Directory -> io ()
closeDir (MkDir d) = primIO (prim__closeDir d)
||| Remove the directory at the specified path.
||| If the directory is not empty, this operation fails.
export
removeDir : HasIO io => String -> io ()
removeDir dirName = primIO (prim__removeDir dirName)
||| Get the next entry in the `Directory`, omitting the '.' and '..' entries.
export
nextDirEntry : HasIO io => Directory -> io (Either FileError (Maybe String))
nextDirEntry (MkDir d)
= do res <- primIO (prim__dirEntry d)
if prim__nullPtr res /= 0
then if !(getErrno) /= 0
then returnError
else pure $ Right Nothing
else do let n = prim__getString res
if n == "." || n == ".."
then assert_total $ nextDirEntry (MkDir d)
else pure $ Right (Just n)
||| Get a list of all the entries in the `Directory`, excluding the '.' and '..'
||| entries.
collectDir : HasIO io => Directory -> io (Either FileError (List String))
collectDir d
= liftIO $ do let (>>=) : (IO . Either e) a -> (a -> (IO . Either e) b) -> (IO . Either e) b
(>>=) = Prelude.(>>=) @{Monad.Compose {m = IO} {t = Either e}}
Just n <- nextDirEntry d
| Nothing => pure $ Right []
ns <- assert_total $ collectDir d
pure $ Right (n :: ns)
||| Get a list of all the entries in the directory at the specified path,
||| excluding the '.' and '..' entries.
|||
||| @ name the directory to list
export
listDir : HasIO io => (name : String) -> io (Either FileError (List String))
listDir name = do Right d <- openDir name
| Left e => pure $ Left e
ns <- collectDir d
ignore <- closeDir d
pure $ ns