Add TODO

.gitignore

@@ -8,5 +8,3 @@ TAGS
 tags
 *.tag
 .stack-work/
-.cabal-sandbox/
-cabal.sandbox.config

CHANGELOG

@@ -1,5 +1,3 @@
-0.5.8:
-	* First version of the fork.
 0.5.7:
 	* Fix haddock problem.
 0.5.6:

LICENSE

@@ -1,5 +1,4 @@
 Copyright (c) 2015–2016, FP Complete
-Copyright (c) 2016, Julian Ospald
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without

README.md

@@ -1,42 +1,518 @@
-# HPath
+# Path
 
-Support for well-typed paths in Haskell. Also provides ByteString based filepath
+Support for well-typed paths in Haskell.
-manipulation.
+
+* [Motivation](#motivation)
+* [Approach](#approach)
+* [Solution](#solution)
+* [Implementation](#implementation)
+    * [The data types](#the-data-types)
+    * [Parsers](#parsers)
+    * [Smart constructors](#smart-constructors)
+    * [Overloaded stings](#overloaded-strings)
+    * [Operations](#operations)
+* [Review](#review)
+    * [Relative vs absolute confusion](#relative-vs-absolute-confusion)
+    * [The equality problem](#the-equality-problem)
+    * [Unpredictable concatenation issues](#unpredictable-concatenation-issues)
+    * [Confusing files and directories](#confusing-files-and-directories)
+    * [Self-documentation](#self-documentation)
+* [In practice](#in-practice)
+* [Doing I/O](#doing-io)
+* [Doing textual manipulations](#doing-textual-manipulations)
+* [Accepting user input](#accepting-user-input)
+* [Comparing with existing path libraries](#comparing-with-existing-path-libraries)
+    * [filepath and system-filepath](#filepath-and-system-filepath)
+    * [system-canonicalpath, canonical-filepath, directory-tree](#system-canonicalpath-canonical-filepath-directory-tree)
+    * [pathtype](#pathtype)
+    * [data-filepath](#data-filepath)
+* [Summary](#summary)
 
 ## Motivation
 
-The motivation came during development of
+It was after working on a number of projects at FP Complete that use file
-[hsfm](https://github.com/hasufell/hsfm)
+paths in various ways. We used the system-filepath package, which was
-which has a pretty strict File type, but lacks a strict Path type, e.g.
+supposed to solve many path problems by being an opaque path type. It
-for user input.
+occurred to me that the same kind of bugs kept cropping up:
 
-The library that came closest to my needs was
+* Expected a path to be absolute but it was relative, or vice-versa.
-[path](https://github.com/chrisdone/path),
-but the API turned out to be oddly complicated for my use case, so I
-decided to fork it.
 
-Similarly, [posix-paths](https://github.com/JohnLato/posix-paths)
+* Expected two equivalent paths to be equal or order the same, but they did
-was exactly what I wanted for the low-level operations, but upstream seems dead,
+  not (`/home//foo` vs `/home/foo/` vs `/home/bar/../foo`, etc.).
-so it is forked as well and merged into this library.
 
-## Differences to 'path'
+* Unpredictable behaviour with regards to concatenating paths.
 
-* doesn't attempt to fake IO-related information into the path, so whether a path points to a file or directory is up to your IO-code to decide...
+* Confusing files and directories.
-* trailing path separators will be preserved if they exist, no messing with that
-* uses safe ByteString for filepaths under the hood instead of unsafe String
-* fixes broken [dirname](https://github.com/chrisdone/path/issues/18)
-* renames dirname/filename to basename/dirname to match the POSIX shell functions
-* introduces a new `Path Fn` for safe filename guarantees and a `RelC` class
-* allows pattern matching via unidirectional PatternSynonym
-* uses simple doctest for testing
-* allows `~/` as relative path, because on posix level `~` is just a regular filename that does _NOT_ point to `$HOME`
-* remove TH, it sucks
 
-## Differences to 'posix-paths'
+* Not knowing whether a path was a file or directory or relative or absolute
+  based on the type alone was a drag.
 
-* `hasTrailingPathSeparator` behaves in the same way as `System.FilePath`
+All of these bugs are preventable.
-* `dropTrailingPathSeparator` behaves in the same way as `System.FilePath`
-* added various functions like `isValid`, `normalise` and `equalFilePath`
-* uses the `word8` package for save word8 literals instead of `OverloadedStrings`
-* has custom versions of `openFd` and `getDirectoryContents`
 
+## Approach
+
+My approach to problems like this is to make a type that encodes the
+properties I want and then make it impossible to let those invariants be
+broken, without compromise or backdoors to let the wrong value “slip
+in”. Once I have a path, I want to be able to trust it fully. This theme
+will be seen throughout the things I lay out below.
+
+## Solution
+
+After having to fix bugs due to these in our software, I put my foot down
+and made:
+
+* An opaque `Path` type (a newtype wrapper around `String`).
+
+* Smart constructors which are very stringent in the parsing.
+
+* Make the parsers highly normalizing.
+
+* Leave equality and concatenation to basic string equality and
+  concatenation.
+
+* Include relativity (absolute/relative) and type (directory/file) in the
+  type itself.
+
+* Use the already cross-platform
+  [filepath](http://hackage.haskell.org/package/filepath) package for
+  implementation details.
+
+## Implementation
+
+### The data types
+
+Here is the type:
+
+```haskell
+newtype Path b t = Path FilePath
+  deriving (Typeable)
+```
+
+The type variables are:
+
+* `b` — base, the base location of the path; absolute or relative.
+* `t` — type, whether file or directory.
+
+The base types can be filled with these:
+
+```haskell
+data Abs deriving (Typeable)
+data Rel deriving (Typeable)
+```
+
+And the type can be filled with these:
+
+```haskell
+data File deriving (Typeable)
+data Dir deriving (Typeable)
+```
+
+(Why not use data kinds like `data Type = File | Dir`? Because that imposes
+an extension overhead of adding `{-# LANGUAGE DataKinds #-}` to every module
+you might want to write out a path type in. Given that one cannot construct
+paths of types other than these, via the operations in the module, it’s not
+a concern for me.)
+
+There is a conversion function to give you back the filepath:
+
+```haskell
+toFilePath :: Path b t -> FilePath
+toFilePath (Path l) = l
+```
+
+Beginning from version 0.5.3, there are type-constrained versions of
+`toFilePath` with the following signatures:
+
+```haskell
+fromAbsDir  :: Path Abs Dir -> FilePath
+fromRelDir  :: Path Rel Dir -> FilePath
+fromAbsFile :: Path Abs File -> FilePath
+fromRelFile :: Path Rel File -> FilePath
+```
+
+### Parsers
+
+To get a `Path` value, you need to use one of the four parsers:
+
+```haskell
+parseAbsDir  :: MonadThrow m => FilePath -> m (Path Abs Dir)
+parseRelDir  :: MonadThrow m => FilePath -> m (Path Rel Dir)
+parseAbsFile :: MonadThrow m => FilePath -> m (Path Abs File)
+parseRelFile :: MonadThrow m => FilePath -> m (Path Rel File)
+```
+
+The following properties apply:
+
+* Absolute parsers will reject non-absolute paths.
+
+* The only delimiter syntax accepted is the path separator; `/` on POSIX and
+  `\` on Windows.
+
+* Any other delimiter is rejected; `..`, `~/`, `/./`, etc.
+
+* All parsers normalize into single separators: `/home//foo` → `/home/foo`.
+
+* Directory parsers always normalize with a final trailing `/`. So `/home/foo`
+  parses into the string `/home/foo/`.
+
+It was discussed briefly whether we should just have a class for parsing
+rather than four separate parsing functions. In my experience so far, I have
+had type errors where I wrote something `like x <- parseAbsDir
+someAbsDirString` because `x` was then passed to a place that expected a
+relative directory. In this way, overloading the return value would’ve just
+been accepted. So I don’t think having a class is a good idea. Being
+explicit here doesn’t exactly waste our time, either.
+
+Why are these functions in `MonadThrow`? Because it means I can have it
+return an `Either`, or a `Maybe`, if I’m in pure code, and if I’m in `IO`,
+and I don’t expect parsing to ever fail, I can use it in IO like this:
+
+```haskell
+do x <- parseRelFile (fromCabalFileName x)
+   foo x
+   …
+```
+
+That’s really convenient and we take advantage of this at FP Complete a lot.
+The instances
+
+Equality, ordering and printing are simply re-using the `String` instances:
+
+```haskell
+instance Eq (Path b t) where
+  (==) (Path x) (Path y) = x == y
+
+instance Ord (Path b t) where
+  compare (Path x) (Path y) = compare x y
+
+instance Show (Path b t) where
+  show (Path x) = show x
+```
+
+Which gives us for free the following equational properties:
+
+```haskell
+toFilePath x == toFilePath y        ≡ x == y           -- Eq instance
+toFilePath x `compare` toFilePath y ≡ x `compare` y    -- Ord instance
+toFilePath x == toFilePath y        ≡ show x == show y -- Show instance
+```
+
+In other words, the representation and the path you get out at the end are
+the same. Two paths that are equal will always give you back the same thing.
+
+### Smart constructors
+
+For when you know what a path will be at compile-time, there are
+constructors for that:
+
+```haskell
+$(mkAbsDir "/home/chris")
+$(mkRelDir "chris")
+$(mkAbsFile "/home/chris/x.txt")
+$(mkRelFile "chris/x.txt")
+```
+
+These will run at compile-time and underneath use the appropriate parser.
+
+### Overloaded strings
+
+No `IsString` instance is provided, because that has no way to statically
+determine whether the path is correct, and would otherwise have to be a
+partial function.
+
+In practice I have written the wrong path format in a `$(mk… "")` and been
+thankful it was caught early.
+
+### Operations
+
+There is path concatenation:
+
+```haskell
+(</>) :: Path b Dir -> Path Rel t -> Path b t
+```
+
+Get the parent directory of a path:
+
+```haskell
+parent :: Path Abs t -> Path Abs Dir
+```
+
+Get the filename of a file path:
+
+```haskell
+filename :: Path b File -> Path Rel File
+```
+
+Get the directory name of a directory path:
+
+```haskell
+dirname :: Path b Dir -> Path Rel Dir
+```
+
+Stripping the parent directory from a path:
+
+```haskell
+stripDir :: MonadThrow m => Path b Dir -> Path b t -> m (Path Rel t)
+```
+
+## Review
+
+Let’s review my initial list of complaints and see if they’ve been
+satisfied.
+
+### Relative vs absolute confusion
+
+Paths now distinguish in the type system whether they are relative or
+absolute. You can’t append two absolute paths, for example:
+
+```haskell
+λ> $(mkAbsDir "/home/chris") </> $(mkAbsDir "/home/chris")
+<interactive>:23:31-55:
+    Couldn't match type ‘Abs’ with ‘Rel’
+```
+
+### The equality problem
+
+Paths are now stringently normalized. They have to be a valid path, and they
+only support single path separators, and all directories are suffixed with a
+trailing path separator:
+
+```haskell
+λ> $(mkAbsDir "/home/chris//") == $(mkAbsDir "/./home//chris")
+True
+λ> toFilePath $(mkAbsDir "/home/chris//") ==
+   toFilePath $(mkAbsDir "/./home//chris")
+True
+λ> ($(mkAbsDir "/home/chris//"),toFilePath $(mkAbsDir "/./home//chris"))
+("/home/chris/","/home/chris/")
+```
+
+### Unpredictable concatenation issues
+
+Because of the stringent normalization, path concatenation, as seen above,
+is simply string concatenation. This is about as predictable as it can get:
+
+```haskell
+λ> toFilePath $(mkAbsDir "/home/chris//")
+"/home/chris/"
+λ> toFilePath $(mkRelDir "foo//bar")
+"foo/bar/"
+λ> $(mkAbsDir "/home/chris//") </> $(mkRelDir "foo//bar")
+"/home/chris/foo/bar/"
+```
+
+### Confusing files and directories
+
+Now that the path type is encoded in the type system, our `</>` operator
+prevents improper appending:
+
+```haskell
+λ> $(mkAbsDir "/home/chris/") </> $(mkRelFile "foo//bar")
+"/home/chris/foo/bar"
+λ> $(mkAbsFile "/home/chris") </> $(mkRelFile "foo//bar")
+<interactive>:35:1-26:
+    Couldn't match type ‘File’ with ‘Dir’
+```
+
+### Self-documentation
+
+Now I can read the path like:
+
+```haskell
+{ fooPath :: Path Rel Dir, ... }
+```
+
+And know that this refers to the directory relative to some other path,
+meaning I should be careful to consider the current directory when using
+this in IO, or that I’ll probably need a parent to append to it at some
+point.
+
+## In practice
+
+We’ve been using this at FP Complete in a number of packages for some months
+now, it’s turned out surprisingly sufficient for most of our path work with
+only one bug found. We weren’t sure initially whether it would just be too
+much of a pain to use, but really it’s quite acceptable given the
+advantages. You can see its use all over the
+[`stack`](https://github.com/commercialhaskell/stack) codebase.
+
+## Doing I/O
+
+Currently any operations involving I/O can be done by using the existing I/O
+library:
+
+```haskell
+doesFileExist (toFilePath fp)
+readFile (toFilePath fp)
+```
+
+etc. This has problems with respect to accidentally running something like:
+
+```haskell
+doesFileExist $(mkRelDir "foo")
+```
+
+But I/O is currently outside the scope of what this package solves. Once you
+leave the realm of the `Path` type invariants are back to your responsibility.
+
+As with the original version of this library, we’re currently building up a
+set of functions in a `Path.IO` module over time that fits our real-world
+use-cases. It may or may not appear in the path package eventually. It’ll
+need cleaning up and considering what should really be included.
+
+**Edit:** There is now
+[`path-io`](https://hackage.haskell.org/package/path-io) package that
+complements the `path` library and includes complete well-typed interface to
+[`directory`](https://hackage.haskell.org/package/directory) and
+[`temporary`](https://hackage.haskell.org/package/temporary). There is work
+to add more generally useful functions from Stack's `Path.IO` to it and make
+Stack depend on the `path-io` package.
+
+## Doing textual manipulations
+
+One problem that crops up sometimes is wanting to manipulate
+paths. Currently the way we do it is via the filepath library and re-parsing
+the path:
+
+```haskell
+parseAbsFile . addExtension "/directory/path" "ext" . toFilePath
+```
+
+It doesn’t happen too often, in our experience, to the extent this needs to
+be more convenient.
+
+## Accepting user input
+
+Sometimes you have user input that contains `../`. The solution we went with
+is to have a function like `resolveDir`:
+
+```haskell
+resolveDir :: (MonadIO m, MonadThrow m)
+           => Path Abs Dir -> FilePath -> m (Path Abs Dir)
+```
+
+Which will call `canonicalizePath` which collapses and normalizes a path and
+then we parse with regular old `parseAbsDir` and we’re cooking with
+gas. This and others like it might get added to the `path` package.
+
+## Comparing with existing path libraries
+
+### filepath and system-filepath
+
+The [filepath](http://hackage.haskell.org/package/filepath) package is
+intended as the complimentary package to be used before parsing into a Path
+value, and/or after printing from a Path value. The package itself contains
+no type-safety, instead contains a range of cross-platform textual
+operations. Definitely reach for this library when you want to do more
+involved manipulations.
+
+The `system-filepath` package is deprecated in favour of `filepath`.
+
+### system-canonicalpath, canonical-filepath, directory-tree
+
+The
+[`system-canonicalpath`](http://hackage.haskell.org/package/system-canonicalpath)
+and the
+[`canonical-filepath`](http://hackage.haskell.org/package/canonical-filepath)
+packages both are a kind of subset of `path`. They canonicalize a string
+into an opaque path, but neither distinguish directories from files or
+absolute/relative. Useful if you just want a canonical path but doesn’t do
+anything else.
+
+The [`directory-tree`](http://hackage.haskell.org/package/directory-tree)
+package contains a sum type of dir/file/etc but doesn’t distinguish in its
+operations relativity or path type.
+
+### pathtype
+
+Finally, we come to a path library that path is similar to: the
+[`pathtype`](http://hackage.haskell.org/package/pathtype) library. There are
+the same types of `Path Abs File` / `Path Rel Dir`, etc.
+
+The points where this library isn’t enough for me are:
+
+* There is an `IsString` instance, which means people will use it, and will
+  make mistakes.
+
+* Paths are not normalized into a predictable format, leading to me being
+  unsure when equality will succeed. This is the same problem I encountered
+  in `system-filepath`. The equality function normalizes, but according to
+  what properties I can reason about? I don’t know.
+
+```haskell
+System.Path.Posix> ("/tmp//" :: Path a Dir) == ("/tmp" :: Path a Dir)
+True
+System.Path.Posix> ("tmp" :: Path a Dir) == ("/tmp" :: Path a Dir)
+True
+System.Path.Posix> ("/etc/passwd/" :: Path a b) == ("/etc/passwd" :: Path a b)
+True
+System.Path.Posix> ("/tmp//" :: Path Abs Dir) == ("/tmp/./" :: Path Abs Dir)
+False
+System.Path.Posix> ("/tmp/../" :: Path Abs Dir) == ("/" :: Path Abs Dir)
+False
+```
+* Empty string should not be allowed, and introduction of `.` due to that
+  gets weird:
+
+```haskell
+System.Path.Posix> fmap getPathString (Right ("." :: Path Rel File))
+Right "."
+System.Path.Posix> fmap getPathString (mkPathAbsOrRel "")
+Right "."
+System.Path.Posix> (Right ("." :: Path Rel File)) == (mkPathAbsOrRel "")
+False
+System.Path.Posix> takeDirectory ("tmp" :: Path Rel Dir)
+.
+System.Path.Posix> (getPathString ("." :: Path Rel File) ==
+                    getPathString ("" :: Path Rel File))
+True
+System.Path.Posix> (("." :: Path Rel File) == ("" :: Path Rel File))
+False
+```
+
+* It has functions like `<.>/addExtension` which lets you insert an
+  arbitrary string into a path.
+
+* Some functions let you produce nonsense (could be prevented by a stricter
+  type), for example:
+
+```haskell
+System.Path.Posix> takeFileName ("/tmp/" :: Path Abs Dir)
+tmp
+```
+
+I’m being a bit picky here, a bit unfair. But the point is really to show
+the kind of things I tried to avoid in `path`. In summary, it’s just hard to
+know where things can go wrong, similar to what was going on in
+`system-filepath`.
+
+### data-filepath
+
+The [`data-filepath`](https://hackage.haskell.org/package/data-filepath) is
+also very similar, I discovered it after writing my own at work and was
+pleased to see it’s mostly the same. The main differences are:
+
+* Uses `DataKinds` for the relative/absolute and file/dir distinction which
+  as I said above is an overhead.
+
+* Uses a GADT for the path type, which is fine. In my case I wanted to
+  retain the original string which functions that work on the `FilePath`
+  (`String`) type already deal with well. It does change the parsing step
+  somewhat, because it parses into segments.
+
+* It’s more lenient at parsing (allowing `..` and trailing `.`).
+
+The API is a bit awkward to just parse a directory, requires a couple
+functions to get it (going via `WeakFilePath`), returning only an `Either`,
+and there are no functions like parent. But there’s not much to complain
+about. It’s a fine library, but I didn’t feel the need to drop my own in
+favor of it. Check it out and decide for yourself.
+
+## Summary
+
+There’s a growing interest in making practical use of well-typed file path
+handling. I think everyone’s wanted it for a while, but few people have
+really committed to it in practice. Now that I’ve been using `path` for a
+while, I can’t really go back. It’ll be interesting to see what new packages
+crop up in the coming year, I expect there’ll be more.

benchmarks/Bench.hs

@@ -1,90 +0,0 @@
-{-# LANGUAGE ForeignFunctionInterface #-}
-{-# LANGUAGE OverloadedStrings #-}
-{-# LANGUAGE TupleSections #-}
-{-# LANGUAGE ViewPatterns #-}
-
-{-# OPTIONS_GHC -Wall #-}
-import Control.Applicative
-import Control.Monad
-import System.Directory
-import System.FilePath ((</>))
-import System.Posix.ByteString.FilePath
-import System.Posix.Directory.ByteString as PosixBS
-import System.Posix.Directory.Traversals
-import qualified System.Posix.FilePath as PosixBS
-import System.Posix.Files.ByteString
-
-import Control.Exception
-import qualified Data.ByteString.Char8 as BS
-
-import System.Environment (getArgs, withArgs)
-import System.IO.Error
-import System.IO.Unsafe
-import System.Process (system)
-import Criterion.Main
-
-
--- | Based on code from 'Real World Haskell', at
--- http://book.realworldhaskell.org/read/io-case-study-a-library-for-searching-the-filesystem.html#id620419
-listFilesRecursive :: FilePath -> IO [FilePath]
-listFilesRecursive topdir = do
-    names <- System.Directory.getDirectoryContents topdir
-    let properNames = filter (`notElem` [".", ".."]) names
-    paths <- forM properNames $ \name -> do
-        let path = topdir </> name
-        isDir <- doesDirectoryExist path
-        if isDir
-            then listFilesRecursive path
-            else return [path]
-    return (topdir : concat paths)
-
-----------------------------------------------------------
-
-getDirectoryContentsBS :: RawFilePath -> IO [RawFilePath]
-getDirectoryContentsBS path = 
-  modifyIOError ((`ioeSetFileName` (BS.unpack path)) .
-                 (`ioeSetLocation` "getDirectoryContentsBS")) $ do
-    bracket
-      (PosixBS.openDirStream path)
-      PosixBS.closeDirStream
-      loop
- where
-  loop dirp = do
-     e <- PosixBS.readDirStream dirp
-     if BS.null e then return [] else do
-       es <- loop dirp
-       return (e:es)
-
-
--- | similar to 'listFilesRecursive, but uses RawFilePaths
-listFilesRecursiveBS :: RawFilePath -> IO [RawFilePath]
-listFilesRecursiveBS topdir = do
-    names <- getDirectoryContentsBS topdir
-    let properNames = filter (`notElem` [".", ".."]) names
-    paths <- forM properNames $ \name -> unsafeInterleaveIO $ do
-        let path = PosixBS.combine topdir name
-        isDir <- isDirectory <$> getFileStatus path
-        if isDir
-            then listFilesRecursiveBS path
-            else return [path]
-    return (topdir : concat paths)
-----------------------------------------------------------
-
-
-benchTraverse :: RawFilePath -> IO ()
-benchTraverse = traverseDirectory (\() p -> BS.putStrLn p) ()
-
-main :: IO ()
-main = do
-  args <- getArgs
-  let (d,otherArgs) = case args of
-          []   -> ("/usr/local",[])
-          x:xs -> (x,xs)
-  withArgs otherArgs $ defaultMain
-    [ bench "traverse (FilePath)"      $ nfIO $ listFilesRecursive d >>= mapM_ putStrLn
-    , bench "traverse (RawFilePath)"   $ nfIO $ listFilesRecursiveBS (BS.pack d) >>= mapM_ BS.putStrLn
-    , bench "allDirectoryContents"     $ nfIO $ allDirectoryContents (BS.pack d) >>= mapM_ BS.putStrLn
-    , bench "allDirectoryContents'"    $ nfIO $ allDirectoryContents' (BS.pack d) >>= mapM_ BS.putStrLn
-    , bench "traverseDirectory"        $ nfIO $ benchTraverse (BS.pack d)
-    , bench "unix find"                $ nfIO $ void $ system ("find " ++ d)
-    ]

cbits/dirutils.c

@@ -1,7 +0,0 @@
-#include "dirutils.h"
-unsigned int
-    __posixdir_d_type(struct dirent* d)
-    {
-      return(d -> d_type);
-    }
-

cbits/dirutils.h

@@ -1,13 +0,0 @@
-#ifndef POSIXPATHS_CBITS_DIRUTILS_H
-#define POSIXPATHS_CBITS_DIRUTILS_H
-
-#include <stdlib.h>
-#include <dirent.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-
-extern unsigned int
-    __posixdir_d_type(struct dirent* d)
-    ;
-#endif

doctests-hpath.hs

@@ -1,16 +0,0 @@
-{-# LANGUAGE OverloadedStrings #-}
-
-module Main where
-
-import Control.Applicative
-
-import Test.DocTest
-import Test.HUnit
-
-main =
-    doctest
-      ["-isrc"
-      , "-XOverloadedStrings"
-      , "src/HPath.hs"
-      ]
-

doctests-posix.hs

@@ -1,25 +0,0 @@
-{-# LANGUAGE OverloadedStrings #-}
-
-module Main where
-
-import Control.Applicative
-import System.Posix.Directory.Traversals
-
-import Test.DocTest
-import Test.HUnit
-
-main = do
-    doctest
-      [ "-isrc"
-      , "-XOverloadedStrings"
-      , "System.Posix.FilePath"
-      ]
-    runTestTT unitTests
-
-
-unitTests :: Test
-unitTests = test
-    [ TestCase $ do
-        r <- (==) <$> allDirectoryContents "." <*> allDirectoryContents' "."
-        assertBool "allDirectoryContents == allDirectoryContents'" r
-    ]

hpath.cabal

@@ -1,83 +0,0 @@
-name:                hpath
-version:             0.5.8
-synopsis:            Support for well-typed paths
-description:         Support for will-typed paths.
-license:             BSD3
-license-file:        LICENSE
-author:              Julian Ospald <hasufell@posteo.de>
-maintainer:          Julian Ospald <hasufell@posteo.de>
-copyright:           2015–2016 FP Complete, Julian Ospald 2016
-category:            Filesystem
-build-type:          Simple
-cabal-version:       >=1.14
-extra-source-files:  README.md
-                     CHANGELOG
-                     cbits/dirutils.h
-                     doctests.hs
-                     benchmarks/*.hs
-
-library
-  hs-source-dirs:    src/
-  default-language:  Haskell2010
-  ghc-options:       -Wall -O2
-  c-sources:         cbits/dirutils.c
-  exposed-modules:   HPath,
-                     HPath.Internal,
-                     System.Posix.Directory.Foreign,
-                     System.Posix.Directory.Traversals,
-                     System.Posix.FilePath
-  build-depends:     base >= 4.2 && <5
-                   , bytestring >= 0.9.2.0
-                   , deepseq
-                   , exceptions
-                   , hspec
-                   , unix >= 2.5
-                   , utf8-string
-                   , word8
-
-
-test-suite doctests-hpath
-  default-language:  Haskell2010
-  type:              exitcode-stdio-1.0
-  ghc-options:       -threaded
-  main-is:           doctests-hpath.hs
-  build-depends:     base
-                   , HUnit
-                   , QuickCheck
-                   , doctest >= 0.8
-                   , hpath
-
-test-suite doctests-posix
-  default-language:  Haskell2010
-  type:              exitcode-stdio-1.0
-  ghc-options:       -threaded
-  main-is:           doctests-posix.hs
-  build-depends:     base,
-                     bytestring,
-                     unix,
-                     hpath,
-                     doctest >= 0.8,
-                     HUnit,
-                     QuickCheck
-
-benchmark bench.hs
-  default-language: Haskell2010
-  type: exitcode-stdio-1.0
-  hs-source-dirs: benchmarks
-  main-is:        Bench.hs
-
-  build-depends:
-      base,
-      hpath,
-      bytestring,
-      unix,
-      directory  >= 1.1 && < 1.3,
-      filepath   >= 1.2 && < 1.4,
-      process    >= 1.0 && < 1.3,
-      criterion  >= 0.6 && < 0.9
-  ghc-options: -O2
-
-source-repository head
-  type:     git
-  location: https://github.com/hasufell/hpath
-

path.cabal

@@ -0,0 +1,37 @@
+name:                path
+version:             0.5.7
+synopsis:            Support for well-typed paths
+description:         Support for will-typed paths.
+license:             BSD3
+license-file:        LICENSE
+author:              Chris Done <chrisdone@fpcomplete.com>
+maintainer:          Chris Done <chrisdone@fpcomplete.com>
+copyright:           2015–2016 FP Complete
+category:            Filesystem
+build-type:          Simple
+cabal-version:       >=1.8
+extra-source-files:  README.md, CHANGELOG
+
+library
+  hs-source-dirs:    src/
+  ghc-options:       -Wall -O2
+  exposed-modules:   Path, Path.Internal
+  build-depends:     base >= 4 && <5
+                   , exceptions
+                   , filepath
+                   , template-haskell
+                   , deepseq
+
+test-suite test
+    type: exitcode-stdio-1.0
+    main-is: Main.hs
+    hs-source-dirs: test
+    build-depends: HUnit
+                 , base
+                 , hspec
+                 , mtl
+                 , path
+
+source-repository head
+    type:     git
+    location: https://github.com/chrisdone/path.git

src/HPath.hs

@@ -1,492 +0,0 @@
--- |
--- Module      :  HPath
--- Copyright   :  © 2015–2016 FP Complete, 2016 Julian Ospald
--- License     :  BSD 3 clause
---
--- Maintainer  :  Julian Ospald <hasufell@posteo.de>
--- Stability   :  experimental
--- Portability :  portable
---
--- Support for well-typed paths.
-
-
-{-# LANGUAGE CPP #-}
-{-# LANGUAGE DeriveDataTypeable #-}
-{-# LANGUAGE EmptyDataDecls #-}
-{-# LANGUAGE PatternSynonyms #-}
-{-# OPTIONS_HADDOCK ignore-exports #-}
-
-module HPath
-  (
-  -- * Types
-   Abs
-  ,Path
-  ,Rel
-  ,Fn
-  ,PathParseException
-  -- * PatternSynonyms/ViewPatterns
-  ,pattern Path
-   -- * Path Parsing
-  ,parseAbs
-  ,parseFn
-  ,parseRel
-  -- * Path Conversion
-  ,canonicalizePath
-  ,fromAbs
-  ,fromRel
-  ,normalize
-  ,toFilePath
-  -- * Path Operations
-  ,(</>)
-  ,basename
-  ,dirname
-  ,isParentOf
-  ,getAllParents
-  ,stripDir
-  -- * Path IO helpers
-  ,withAbsPath
-  ,withRelPath
-  ,withFnPath
-  -- * ByteString/Word8 constants
-  ,nullByte
-  ,pathDot
-  ,pathDot'
-  ,pathSeparator'
-  -- * ByteString operations
-  ,fpToString
-  ,userStringToFP
-  -- * ByteString Query functions
-  ,hiddenFile
-  -- * Queries
-  ,hasParentDir
-  ,isFileName
-  -- * String based functions
-  )
-  where
-
-import           Control.Exception (Exception)
-import           Control.Monad.Catch (MonadThrow(..))
-import           Data.ByteString(ByteString)
-import qualified Data.ByteString as BS
-import           Data.ByteString.UTF8 (fromString, toString)
-import           Data.Data
-import qualified Data.List as L
-import           Data.Maybe
-import           Data.Word8
-import           HPath.Internal
-import           System.Posix.FilePath hiding ((</>))
-import           System.Posix.Directory.Traversals(realpath)
-
-
---------------------------------------------------------------------------------
--- Types
-
--- | An absolute path.
-data Abs deriving (Typeable)
-
--- | A relative path; one without a root.
-data Rel deriving (Typeable)
-
--- | A filename, without any '/'.
-data Fn deriving (Typeable)
-
--- | Exception when parsing a location.
-data PathParseException
-  = InvalidAbs ByteString
-  | InvalidRel ByteString
-  | InvalidFn ByteString
-  | Couldn'tStripPrefixTPS ByteString ByteString
-  deriving (Show,Typeable)
-instance Exception PathParseException
-
-data PathException = RootDirHasNoBasename
-  deriving (Show,Typeable)
-instance Exception PathException
-
-instance RelC Rel
-instance RelC Fn
-
---------------------------------------------------------------------------------
--- PatternSynonyms
-
-pattern Path x <- (MkPath x)
-
---------------------------------------------------------------------------------
--- Path Parsers
-
-
-
--- | Get a location for an absolute path. Produces a normalised path.
---
--- Throws: 'PathParseException'
---
--- >>> parseAbs "/abc" :: Maybe (Path Abs)
--- Just "/abc"
--- >>> parseAbs "/" :: Maybe (Path Abs)
--- Just "/"
--- >>> parseAbs "/abc/def" :: Maybe (Path Abs)
--- Just "/abc/def"
--- >>> parseAbs "/abc/def/.///" :: Maybe (Path Abs)
--- Just "/abc/def/"
--- >>> parseAbs "abc" :: Maybe (Path Abs)
--- Nothing
--- >>> parseAbs "" :: Maybe (Path Abs)
--- Nothing
--- >>> parseAbs "/abc/../foo" :: Maybe (Path Abs)
--- Nothing
-parseAbs :: MonadThrow m
-         => ByteString -> m (Path Abs)
-parseAbs filepath =
-  if isAbsolute filepath &&
-     isValid filepath &&
-     not (hasParentDir filepath)
-     then return (MkPath $ normalise filepath)
-     else throwM (InvalidAbs filepath)
-
-
--- | Get a location for a relative path. Produces a normalised
--- path.
---
--- Note that @filepath@ may contain any number of @./@ but may not consist
--- solely of @./@.  It also may not contain a single @..@ anywhere.
---
--- Throws: 'PathParseException'
---
--- >>> parseRel "abc" :: Maybe (Path Rel)
--- Just "abc"
--- >>> parseRel "def/" :: Maybe (Path Rel)
--- Just "def/"
--- >>> parseRel "abc/def" :: Maybe (Path Rel)
--- Just "abc/def"
--- >>> parseRel "abc/def/." :: Maybe (Path Rel)
--- Just "abc/def/"
--- >>> parseRel "/abc" :: Maybe (Path Rel)
--- Nothing
--- >>> parseRel "" :: Maybe (Path Rel)
--- Nothing
--- >>> parseRel "abc/../foo" :: Maybe (Path Rel)
--- Nothing
--- >>> parseRel "." :: Maybe (Path Rel)
--- Nothing
--- >>> parseRel ".." :: Maybe (Path Rel)
--- Nothing
-parseRel :: MonadThrow m
-         => ByteString -> m (Path Rel)
-parseRel filepath =
-  if not (isAbsolute filepath) &&
-     filepath /= pathDot' && filepath /= pathDoubleDot &&
-     not (hasParentDir filepath) &&
-     isValid filepath
-     then return (MkPath $ normalise filepath)
-     else throwM (InvalidRel filepath)
-
-
--- | Parses a filename. Filenames must not contain slashes.
--- Excludes '.' and '..'.
---
--- Throws: 'PathParseException'
---
--- >>> parseFn "abc" :: Maybe (Path Fn)
--- Just "abc"
--- >>> parseFn "..." :: Maybe (Path Fn)
--- Just "..."
--- >>> parseFn "def/" :: Maybe (Path Fn)
--- Nothing
--- >>> parseFn "abc/def" :: Maybe (Path Fn)
--- Nothing
--- >>> parseFn "abc/def/." :: Maybe (Path Fn)
--- Nothing
--- >>> parseFn "/abc" :: Maybe (Path Fn)
--- Nothing
--- >>> parseFn "" :: Maybe (Path Fn)
--- Nothing
--- >>> parseFn "abc/../foo" :: Maybe (Path Fn)
--- Nothing
--- >>> parseFn "." :: Maybe (Path Fn)
--- Nothing
--- >>> parseFn ".." :: Maybe (Path Fn)
--- Nothing
-parseFn :: MonadThrow m
-        => ByteString -> m (Path Fn)
-parseFn filepath =
-  if isFileName filepath &&
-     filepath /= pathDot' && filepath /= pathDoubleDot &&
-     isValid filepath
-     then return (MkPath filepath)
-     else throwM (InvalidFn filepath)
-
-
-
---------------------------------------------------------------------------------
--- Path Conversion
-
--- | Convert to a ByteString type.
-toFilePath :: Path b -> ByteString
-toFilePath (MkPath l) = l
-
-fromAbs :: Path Abs -> ByteString
-fromAbs = toFilePath
-
-fromRel :: RelC r => Path r -> ByteString
-fromRel = toFilePath
-
-normalize :: Path t -> Path t
-normalize (MkPath l) = MkPath $ normalise l
-
-
---------------------------------------------------------------------------------
--- Path Operations
-
--- | Append two paths.
---
--- The second argument must always be a relative path, which ensures
--- that undefinable things like `"/abc" </> "/def"` cannot happen.
---
--- Technically, the first argument can be a path that points to a non-directory,
--- because this library is IO-agnostic and makes no assumptions about
--- file types.
---
--- >>> (MkPath "/") </> (MkPath "file" :: Path Rel)
--- "/file"
--- >>> (MkPath "/path/to") </> (MkPath "file" :: Path Rel)
--- "/path/to/file"
--- >>> (MkPath "/") </> (MkPath "file/lal" :: Path Rel)
--- "/file/lal"
--- >>> (MkPath "/") </> (MkPath "file/" :: Path Rel)
--- "/file/"
-(</>) :: RelC r => Path b -> Path r -> Path b
-(</>) (MkPath a) (MkPath b) = MkPath (a' `BS.append` b)
-  where
-    a' = if BS.last a == pathSeparator
-         then a
-         else addTrailingPathSeparator a
-
--- | Strip directory from path, making it relative to that directory.
--- Throws 'Couldn'tStripPrefixDir' if directory is not a parent of the path.
---
--- The bases must match.
---
--- >>> (MkPath "/lal/lad") `stripDir` (MkPath "/lal/lad/fad") :: Maybe (Path Rel)
--- Just "fad"
--- >>> (MkPath "lal/lad") `stripDir` (MkPath "lal/lad/fad") :: Maybe (Path Rel)
--- Just "fad"
--- >>> (MkPath "/") `stripDir` (MkPath "/") :: Maybe (Path Rel)
--- Nothing
--- >>> (MkPath "/lal/lad/fad") `stripDir` (MkPath "/lal/lad") :: Maybe (Path Rel)
--- Nothing
--- >>> (MkPath "fad") `stripDir` (MkPath "fad") :: Maybe (Path Rel)
--- Nothing
-stripDir :: MonadThrow m
-         => Path b -> Path b -> m (Path Rel)
-stripDir (MkPath p) (MkPath l) =
-  case stripPrefix p' l of
-    Nothing -> throwM (Couldn'tStripPrefixTPS p' l)
-    Just ok -> if BS.null ok
-                 then throwM (Couldn'tStripPrefixTPS p' l)
-                 else return (MkPath ok)
-  where
-    p' = addTrailingPathSeparator p
-
--- | Is p a parent of the given location? Implemented in terms of
--- 'stripDir'. The bases must match.
---
--- >>> (MkPath "/lal/lad") `isParentOf` (MkPath "/lal/lad/fad")
--- True
--- >>> (MkPath "lal/lad") `isParentOf` (MkPath "lal/lad/fad")
--- True
--- >>> (MkPath "/") `isParentOf` (MkPath "/")
--- False
--- >>> (MkPath "/lal/lad/fad") `isParentOf` (MkPath "/lal/lad")
--- False
--- >>> (MkPath "fad") `isParentOf` (MkPath "fad")
--- False
-isParentOf :: Path b -> Path b -> Bool
-isParentOf p l = isJust (stripDir p l :: Maybe (Path Rel))
-
-
--- |Get all parents of a path.
---
--- >>> getAllParents (MkPath "/abs/def/dod")
--- ["/abs/def","/abs","/"]
--- >>> getAllParents (MkPath "/")
--- []
-getAllParents :: Path Abs -> [Path Abs]
-getAllParents (MkPath p)
-  | np == pathSeparator' = []
-  | otherwise = dirname (MkPath np) : getAllParents (dirname $ MkPath np)
-  where
-    np = dropTrailingPathSeparator . normalise $ p
-
-
--- | Extract the directory name of a path.
---
--- The following properties hold:
---
--- @dirname (p \<\/> a) == dirname p@
---
--- >>> dirname (MkPath "/abc/def/dod")
--- "/abc/def"
--- >>> dirname (MkPath "/")
--- "/"
-dirname :: Path Abs -> Path Abs
-dirname (MkPath fp) = MkPath (takeDirectory $ dropTrailingPathSeparator fp)
-
--- | Extract the file part of a path.
---
---
--- The following properties hold:
---
--- @basename (p \<\/> a) == basename a@
---
--- Throws: `PathException` if given the root path "/"
---
--- >>> basename (MkPath "/abc/def/dod") :: Maybe (Path Fn)
--- Just "dod"
--- >>> basename (MkPath "/") :: Maybe (Path Fn)
--- Nothing
-basename :: MonadThrow m => Path b -> m (Path Fn)
-basename (MkPath l)
-  | not (isAbsolute rl) = return $ MkPath rl
-  | otherwise           = throwM RootDirHasNoBasename
-  where
-    rl = last . splitPath . dropTrailingPathSeparator $ l
-
-
---------------------------------------------------------------------------------
--- Path IO helpers
-
-
--- | May fail on `realpath`.
-canonicalizePath :: Path Abs -> IO (Path Abs)
-canonicalizePath (MkPath l) = do
-  nl <- realpath l
-  return $ MkPath nl
-
-
-withAbsPath :: Path Abs -> (ByteString -> IO a) -> IO a
-withAbsPath (MkPath p) action = action p
-
-
-withRelPath :: Path Rel -> (ByteString -> IO a) -> IO a
-withRelPath (MkPath p) action = action p
-
-
-withFnPath :: Path Fn -> (ByteString -> IO a) -> IO a
-withFnPath (MkPath p) action = action p
-
-
---------------------------------------------------------------------------------
--- ByteString Query functions
-
-
--- | Whether the file is a hidden file.
---
--- >>> hiddenFile (MkPath ".foo")
--- True
--- >>> hiddenFile (MkPath "..foo.bar")
--- True
--- >>> hiddenFile (MkPath "...")
--- True
--- >>> hiddenFile (MkPath "dod")
--- False
--- >>> hiddenFile (MkPath "dod.bar")
--- False
-hiddenFile :: Path Fn -> Bool
-hiddenFile (MkPath fp)
-  | fp == pathDoubleDot = False
-  | fp == pathDot'      = False
-  | otherwise           = pathDot' `BS.isPrefixOf` fp
- 
-
---------------------------------------------------------------------------------
--- ByteString/Word8 constants
-
-pathSeparator' :: ByteString
-pathSeparator' = BS.singleton pathSeparator
-
-
-pathDot :: Word8
-pathDot = _period
-
-
-pathDot' :: ByteString
-pathDot' = BS.singleton pathDot
-
-
-pathDoubleDot :: ByteString
-pathDoubleDot = pathDot `BS.cons` pathDot'
-
-
-nullByte :: Word8
-nullByte = _nul
-
-
---------------------------------------------------------------------------------
--- ByteString Operations
-
-
-
--- |Uses UTF-8 decoding to convert the bytestring into a String.
-fpToString :: ByteString -> String
-fpToString = toString
-
-
--- |Uses UTF-8 encoding to convert a user provided String into
--- a ByteString, which represents a filepath.
-userStringToFP :: String -> ByteString
-userStringToFP = fromString
-
-
-#if MIN_VERSION_bytestring(0,10,8)
-#else
-stripPrefix :: ByteString -> ByteString -> Maybe ByteString
-stripPrefix a b = BS.pack `fmap` L.stripPrefix (BS.unpack a) (BS.unpack b)
-#endif
-
---------------------------------------------------------------------------------
--- ByteString Query functions
-
--- | Helper function: check if the filepath has any parent directories in it.
---
--- >>> hasParentDir "/.."
--- True
--- >>> hasParentDir "foo/bar/.."
--- True
--- >>> hasParentDir "foo/../bar/."
--- True
--- >>> hasParentDir "foo/bar"
--- False
--- >>> hasParentDir "foo"
--- False
--- >>> hasParentDir ""
--- False
--- >>> hasParentDir ".."
--- False
-hasParentDir :: ByteString -> Bool
-hasParentDir filepath =
-  ((pathSeparator `BS.cons` pathDoubleDot)  `BS.isSuffixOf` filepath) ||
-  ((pathSeparator' `BS.append` pathDoubleDot `BS.append` pathSeparator')
-      `BS.isInfixOf`  filepath) ||
-  ((pathDoubleDot `BS.append` pathSeparator') `BS.isPrefixOf` filepath)
-
-
--- | Is the given filename a valid filename?
---
--- >>> isFileName "lal"
--- True
--- >>> isFileName "."
--- True
--- >>> isFileName ".."
--- True
--- >>> isFileName ""
--- False
--- >>> isFileName "\0"
--- False
--- >>> isFileName "/random_ path:*"
--- False
-isFileName :: ByteString -> Bool
-isFileName filepath =
-  not (pathSeparator' `BS.isInfixOf` filepath) &&
-  not (BS.null filepath) &&
-  not (nullByte `BS.elem` filepath)
-

src/Path.hs

@@ -0,0 +1,336 @@
+-- |
+-- Module      :  Path
+-- Copyright   :  © 2015–2016 FP Complete
+-- License     :  BSD 3 clause
+--
+-- Maintainer  :  Chris Done <chrisdone@fpcomplete.com>
+-- Stability   :  experimental
+-- Portability :  portable
+--
+-- Support for well-typed paths.
+
+{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE DeriveDataTypeable #-}
+{-# LANGUAGE EmptyDataDecls #-}
+
+module Path
+  (-- * Types
+   Path
+  ,Abs
+  ,Rel
+   -- * Parsing
+  ,parseAbsDir
+  ,parseRelDir
+  ,parseAbsFile
+  ,parseRelFile
+  ,PathParseException
+  -- * Constructors
+  ,mkAbsDir
+  ,mkRelDir
+  ,mkAbsFile
+  ,mkRelFile
+  -- * Operations
+  ,(</>)
+  ,stripDir
+  ,isParentOf
+  ,parent
+  ,filename
+  -- * Conversion
+  ,toFilePath
+  )
+  where
+
+import           Control.Exception (Exception)
+import           Control.Monad.Catch (MonadThrow(..))
+import           Data.Data
+import           Data.List
+import           Data.Maybe
+import           Language.Haskell.TH
+import           Path.Internal
+import qualified System.FilePath as FilePath
+
+--------------------------------------------------------------------------------
+-- Types
+
+-- | An absolute path.
+data Abs deriving (Typeable)
+
+-- | A relative path; one without a root.
+data Rel deriving (Typeable)
+
+
+-- | Exception when parsing a location.
+data PathParseException
+  = InvalidAbsDir FilePath
+  | InvalidRelDir FilePath
+  | InvalidAbsFile FilePath
+  | InvalidRelFile FilePath
+  | Couldn'tStripPrefixDir FilePath FilePath
+  | InvalidTypeCombination
+  deriving (Show,Typeable)
+instance Exception PathParseException
+
+--------------------------------------------------------------------------------
+-- Parsers
+
+-- | Get a location for an absolute directory. Produces a normalized
+--  path which always ends in a path separator.
+--
+-- Throws: 'PathParseException'
+--
+parseAbsDir :: MonadThrow m
+            => FilePath -> m (Path Abs)
+parseAbsDir filepath =
+  if FilePath.isAbsolute filepath &&
+     not (null (normalizeDir filepath)) &&
+     not ("~/" `isPrefixOf` filepath) &&
+     not (hasParentDir filepath) &&
+     FilePath.isValid filepath
+     then return (DPath (normalizeDir filepath))
+     else throwM (InvalidAbsDir filepath)
+
+-- | Get a location for a relative directory. Produces a normalized
+-- path which always ends in a path separator.
+--
+-- Note that @filepath@ may contain any number of @./@ but may not consist solely of @./@.  It also may not contain a single @..@ anywhere.
+--
+-- Throws: 'PathParseException'
+--
+parseRelDir :: MonadThrow m
+            => FilePath -> m (Path Rel)
+parseRelDir filepath =
+  if not (FilePath.isAbsolute filepath) &&
+     not (null filepath) &&
+     not ("~/" `isPrefixOf` filepath) &&
+     not (hasParentDir filepath) &&
+     not (null (normalizeDir filepath)) &&
+     filepath /= "." && filepath /= ".." &&
+     FilePath.isValid filepath
+     then return (DPath (normalizeDir filepath))
+     else throwM (InvalidRelDir filepath)
+
+-- | Get a location for an absolute file.
+--
+-- Throws: 'PathParseException'
+--
+parseAbsFile :: MonadThrow m
+             => FilePath -> m (Path Abs)
+parseAbsFile filepath =
+  if FilePath.isAbsolute filepath &&
+     not (FilePath.hasTrailingPathSeparator filepath) &&
+     not ("~/" `isPrefixOf` filepath) &&
+     not (hasParentDir filepath) &&
+     not (null (normalizeFile filepath)) &&
+     FilePath.isValid filepath
+     then return (FPath (normalizeFile filepath))
+     else throwM (InvalidAbsFile filepath)
+
+-- | Get a location for a relative file.
+--
+-- Note that @filepath@ may contain any number of @./@ but may not contain a single @..@ anywhere.
+--
+-- Throws: 'PathParseException'
+--
+parseRelFile :: MonadThrow m
+             => FilePath -> m (Path Rel)
+parseRelFile filepath =
+  if not (FilePath.isAbsolute filepath ||
+          FilePath.hasTrailingPathSeparator filepath) &&
+     not (null filepath) &&
+     not ("~/" `isPrefixOf` filepath) &&
+     not (hasParentDir filepath) &&
+     not (null (normalizeFile filepath)) &&
+     filepath /= "." && filepath /= ".." &&
+     FilePath.isValid filepath
+     then return (FPath (normalizeFile filepath))
+     else throwM (InvalidRelFile filepath)
+
+-- | Helper function: check if the filepath has any parent directories in it.
+-- This handles the logic of checking for different path separators on Windows.
+hasParentDir :: FilePath -> Bool
+hasParentDir filepath' =
+     ("/.." `isSuffixOf` filepath) ||
+     ("/../" `isInfixOf` filepath) ||
+     ("../" `isPrefixOf` filepath)
+  where
+    filepath =
+        case FilePath.pathSeparator of
+            '/' -> filepath'
+            x   -> map (\y -> if x == y then '/' else y) filepath'
+
+--------------------------------------------------------------------------------
+-- Constructors
+
+-- | Make a 'Path Abs Dir'.
+--
+-- Remember: due to the nature of absolute paths this (e.g. @\/home\/foo@)
+-- may compile on your platform, but it may not compile on another
+-- platform (Windows).
+mkAbsDir :: FilePath -> Q Exp
+mkAbsDir s =
+  case parseAbsDir s of
+    Left err -> error (show err)
+    Right (DPath str) ->
+      [|DPath $(return (LitE (StringL str))) :: Path Abs|]
+    _ -> error "Invalid Type"
+
+-- | Make a 'Path Rel Dir'.
+mkRelDir :: FilePath -> Q Exp
+mkRelDir s =
+  case parseRelDir s of
+    Left err -> error (show err)
+    Right (DPath str) ->
+      [|DPath $(return (LitE (StringL str))) :: Path Rel|]
+    _ -> error "Invalid Type"
+
+-- | Make a 'Path Abs File'.
+--
+-- Remember: due to the nature of absolute paths this (e.g. @\/home\/foo@)
+-- may compile on your platform, but it may not compile on another
+-- platform (Windows).
+mkAbsFile :: FilePath -> Q Exp
+mkAbsFile s =
+  case parseAbsFile s of
+    Left err -> error (show err)
+    Right (FPath str) ->
+      [|FPath $(return (LitE (StringL str))) :: Path Abs|]
+    _ -> error "Invalid Type"
+
+-- | Make a 'Path Rel File'.
+mkRelFile :: FilePath -> Q Exp
+mkRelFile s =
+  case parseRelFile s of
+    Left err -> error (show err)
+    Right (FPath str) ->
+      [|FPath $(return (LitE (StringL str))) :: Path Rel|]
+    _ -> error "Invalid Type"
+
+--------------------------------------------------------------------------------
+-- Conversion
+
+-- | Convert to a 'FilePath' type.
+--
+-- All directories have a trailing slash, so if you want no trailing
+-- slash, you can use 'System.FilePath.dropTrailingPathSeparator' from
+-- the filepath package.
+toFilePath :: Path b -> FilePath
+toFilePath (FPath l) = l
+toFilePath (DPath l) = l
+
+
+--------------------------------------------------------------------------------
+-- Operations
+
+-- | Append two paths.
+--
+-- The following cases are valid and the equalities hold:
+--
+-- @$(mkAbsDir x) \<\/> $(mkRelDir y) = $(mkAbsDir (x ++ \"/\" ++ y))@
+--
+-- @$(mkAbsDir x) \<\/> $(mkRelFile y) = $(mkAbsFile (x ++ \"/\" ++ y))@
+--
+-- @$(mkRelDir x) \<\/> $(mkRelDir y) = $(mkRelDir (x ++ \"/\" ++ y))@
+--
+-- @$(mkRelDir x) \<\/> $(mkRelFile y) = $(mkRelFile (x ++ \"/\" ++ y))@
+--
+-- The following are proven not possible to express:
+--
+-- @$(mkAbsFile …) \<\/> x@
+--
+-- @$(mkRelFile …) \<\/> x@
+--
+-- @x \<\/> $(mkAbsFile …)@
+--
+-- @x \<\/> $(mkAbsDir …)@
+--
+(</>) :: MonadThrow m => Path b -> Path Rel -> m (Path b)
+(</>) (DPath a) (FPath b) = return $ FPath (a ++ b)
+(</>) (DPath a) (DPath b) = return $ DPath (a ++ b)
+(</>) _         _         = throwM InvalidTypeCombination
+
+-- | Strip directory from path, making it relative to that directory.
+-- Throws 'Couldn'tStripPrefixDir' if directory is not a parent of the path.
+--
+-- The following properties hold:
+--
+-- @stripDir x (x \<\/> y) = y@
+--
+-- Cases which are proven not possible:
+--
+-- @stripDir (a :: Path Abs …) (b :: Path Rel …)@
+--
+-- @stripDir (a :: Path Rel …) (b :: Path Abs …)@
+--
+-- In other words the bases must match.
+--
+stripDir :: MonadThrow m
+         => Path b -> Path b -> m (Path Rel)
+stripDir (DPath p) (FPath l) =
+  case stripPrefix p l of
+    Nothing -> throwM (Couldn'tStripPrefixDir p l)
+    Just "" -> throwM (Couldn'tStripPrefixDir p l)
+    Just ok -> return (FPath ok)
+stripDir (DPath p) (DPath l) =
+  case stripPrefix p l of
+    Nothing -> throwM (Couldn'tStripPrefixDir p l)
+    Just "" -> throwM (Couldn'tStripPrefixDir p l)
+    Just ok -> return (DPath ok)
+stripDir _ _ = throwM InvalidTypeCombination
+
+
+-- | Is p a parent of the given location? Implemented in terms of
+-- 'stripDir'. The bases must match.
+-- Returns False if the first argument is not a directory path.
+isParentOf :: Path b -> Path b -> Bool
+isParentOf p@(DPath _) l@(DPath _) = isJust (stripDir p l)
+isParentOf p@(DPath _) l@(FPath _) = isJust (stripDir p l)
+isParentOf _         _         = False
+
+-- | Take the absolute parent directory from the absolute path.
+--
+-- The following properties hold:
+--
+-- @parent (x \<\/> y) == x@
+--
+-- On the root, getting the parent is idempotent:
+--
+-- @parent (parent \"\/\") = \"\/\"@
+--
+parent :: Path Abs -> Path Abs
+parent (DPath fp) =
+  DPath (normalizeDir (FilePath.takeDirectory (FilePath.dropTrailingPathSeparator fp)))
+parent (FPath fp) =
+  DPath (normalizeDir (FilePath.takeDirectory (FilePath.dropTrailingPathSeparator fp)))
+
+-- | Extract the file/directory part of a path.
+--
+-- The following properties hold:
+--
+-- @filename (p \<\/> a) == filename a@
+--
+filename :: Path b -> Path Rel
+filename (FPath l) =
+  FPath (normalizeFile (FilePath.takeFileName l))
+filename (DPath l) =
+  DPath (last (FilePath.splitPath l))
+
+
+--------------------------------------------------------------------------------
+-- Internal functions
+
+-- | Internal use for normalizing a directory.
+normalizeDir :: FilePath -> FilePath
+normalizeDir =
+  clean . FilePath.addTrailingPathSeparator . FilePath.normalise
+  where clean "./" = ""
+        clean ('/':'/':xs) = clean ('/':xs)
+        clean x = x
+
+-- | Internal use for normalizing a fileectory.
+normalizeFile :: FilePath -> FilePath
+normalizeFile =
+  clean . FilePath.normalise
+  where clean "./" = ""
+        clean ('/':'/':xs) = clean ('/':xs)
+        clean x = x
+

src/Path/Internal.hs

@@ -1,26 +1,29 @@
 {-# LANGUAGE DeriveDataTypeable #-}
 
+-- TODO: - remove undefined in Ord instance
+--       - use viewpatterns/patternsynonyms so we don't need to
+--         export the constructors
+
 -- | Internal types and functions.
 
-module HPath.Internal
+module Path.Internal
-  (Path(..)
+  (Path(..))
-  ,RelC)
   where
 
 import Control.DeepSeq (NFData (..))
-import Data.ByteString (ByteString)
 import Data.Data
 
 -- | Path of some base and type.
 --
 -- Internally is a string. The string can be of two formats only:
 --
--- 1. without trailing path separator: @file.txt@, @foo\/bar.txt@, @\/foo\/bar.txt@
+-- 1. File format: @file.txt@, @foo\/bar.txt@, @\/foo\/bar.txt@
--- 2. with trailing path separator: @foo\/@, @\/foo\/bar\/@
+-- 2. Directory format: @foo\/@, @\/foo\/bar\/@
 --
--- There are no duplicate
+-- All directories end in a trailing separator. There are no duplicate
 -- path separators @\/\/@, no @..@, no @.\/@, no @~\/@, etc.
-data Path b = MkPath ByteString
+data Path b = FPath FilePath
+            | DPath FilePath
   deriving (Typeable)
 
 -- | String equality.
@@ -29,7 +32,9 @@ data Path b = MkPath ByteString
 --
 -- @show x == show y ≡ x == y@
 instance Eq (Path b) where
-  (==) (MkPath x) (MkPath y) = x == y
+  (==) (FPath x) (FPath y) = x == y
+  (==) (DPath x) (DPath y) = x == y
+  (==) _         _         = False
 
 -- | String ordering.
 --
@@ -37,7 +42,9 @@ instance Eq (Path b) where
 --
 -- @show x \`compare\` show y ≡ x \`compare\` y@
 instance Ord (Path b) where
-  compare (MkPath x) (MkPath y) = compare x y
+  compare (FPath x) (FPath y) = compare x y
+  compare (DPath x) (DPath y) = compare x y
+  compare _         _         = undefined
 
 -- | Same as 'Path.toFilePath'.
 --
@@ -45,11 +52,10 @@ instance Ord (Path b) where
 --
 -- @x == y ≡ show x == show y@
 instance Show (Path b) where
-  show (MkPath x) = show x
+  show (FPath x) = show x
+  show (DPath x) = show x
 
 instance NFData (Path b) where
-  rnf (MkPath x) = rnf x
+  rnf (FPath x) = rnf x
-
+  rnf (DPath x) = rnf x
-
-class RelC m
 

src/System/Posix/Directory/Foreign.hsc

@@ -1,55 +0,0 @@
-module System.Posix.Directory.Foreign where
-
-import Data.Bits
-import Data.List (foldl')
-import Foreign.C.Types
-
-#include <limits.h>
-#include <stdlib.h>
-#include <dirent.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-
-newtype DirType = DirType Int deriving (Eq, Show)
-data Flags = Flags Int | UnsupportedFlag String deriving (Eq, Show)
-
-unFlags :: Flags -> Int
-unFlags (Flags i) = i
-unFlags (UnsupportedFlag name) = error (name ++ " is not supported on this platform")
-
--- |Returns @True@ if posix-paths was compiled with support for the provided
--- flag. (As of this writing, the only flag for which this check may be
--- necessary is 'oCloexec'; all other flags will always yield @True@.)
-isSupported :: Flags -> Bool
-isSupported (Flags _) = True
-isSupported _ = False
-
--- |@O_CLOEXEC@ is not supported on every POSIX platform. Use
--- @'isSupported' oCloexec@ to determine if support for @O_CLOEXEC@ was
--- compiled into your version of posix-paths. (If not, using @oCloexec@ will
--- throw an exception.)
-oCloexec :: Flags
-#ifdef O_CLOEXEC
-oCloexec = Flags #{const O_CLOEXEC}
-#else
-{-# WARNING oCloexec
-    "This version of posix-paths was compiled without @O_CLOEXEC@ support." #-}
-oCloexec = UnsupportedFlag "O_CLOEXEC"
-#endif
-
-
-
--- If these enum declarations occur earlier in the file, haddock
--- gets royally confused about the above doc comments.
--- Probably http://trac.haskell.org/haddock/ticket/138
-
-#{enum DirType, DirType, DT_BLK, DT_CHR, DT_DIR, DT_FIFO, DT_LNK, DT_REG, DT_SOCK, DT_UNKNOWN}
-
-#{enum Flags, Flags, O_APPEND, O_ASYNC, O_CREAT, O_DIRECTORY, O_EXCL, O_NOCTTY, O_NOFOLLOW, O_NONBLOCK, O_RDONLY, O_WRONLY, O_RDWR, O_SYNC, O_TRUNC}
-
-pathMax :: Int
-pathMax = #{const PATH_MAX}
-
-unionFlags :: [Flags] -> CInt
-unionFlags = fromIntegral . foldl' ((. unFlags) . (.|.)) 0

src/System/Posix/Directory/Traversals.hs

@@ -1,269 +0,0 @@
-{-# LANGUAGE ForeignFunctionInterface #-}
-{-# LANGUAGE OverloadedStrings #-}
-{-# LANGUAGE TupleSections #-}
-{-# LANGUAGE ViewPatterns #-}
-
-{-# OPTIONS_GHC -Wall #-}
-module System.Posix.Directory.Traversals (
-
-  getDirectoryContents
-, getDirectoryContents'
-
-, allDirectoryContents
-, allDirectoryContents'
-, traverseDirectory
-
--- lower-level stuff
-, readDirEnt
-, packDirStream
-, unpackDirStream
-, openFd
-
-, realpath
-) where
-
-import Control.Applicative
-import Control.Monad
-import System.Posix.FilePath ((</>))
-import System.Posix.Directory.Foreign
-
-import qualified System.Posix as Posix
-import System.IO.Error
-import Control.Exception
-import qualified Data.ByteString.Char8 as BS
-import System.Posix.ByteString.FilePath
-import System.Posix.Directory.ByteString as PosixBS
-import System.Posix.Files.ByteString
-
-import System.IO.Unsafe
-import Unsafe.Coerce (unsafeCoerce)
-import Foreign.C.Error
-import Foreign.C.String
-import Foreign.C.Types
-import Foreign.Marshal.Alloc (alloca,allocaBytes)
-import Foreign.Ptr
-import Foreign.Storable
-
-
-
-
-----------------------------------------------------------
-
--- | Get all files from a directory and its subdirectories.
---
--- Upon entering a directory, 'allDirectoryContents' will get all entries
--- strictly.  However the returned list is lazy in that directories will only
--- be accessed on demand.
-allDirectoryContents :: RawFilePath -> IO [RawFilePath]
-allDirectoryContents topdir = do
-    namesAndTypes <- getDirectoryContents topdir
-    let properNames = filter ((`notElem` [".", ".."]) . snd) namesAndTypes
-    paths <- forM properNames $ \(typ,name) -> unsafeInterleaveIO $ do
-        let path = topdir </> name
-        case () of
-            () | typ == dtDir -> allDirectoryContents path
-               | typ == dtUnknown -> do
-                    isDir <- isDirectory <$> getFileStatus path
-                    if isDir
-                        then allDirectoryContents path
-                        else return [path]
-               | otherwise -> return [path]
-    return (topdir : concat paths)
-
--- | Get all files from a directory and its subdirectories strictly.
-allDirectoryContents' :: RawFilePath -> IO [RawFilePath]
-allDirectoryContents' = fmap reverse . traverseDirectory (\acc fp -> return (fp:acc)) []
--- this uses traverseDirectory because it's more efficient than forcing the
--- lazy version.
-
--- | Recursively apply the 'action' to the parent directory and all
--- files/subdirectories.
---
--- This function allows for memory-efficient traversals.
-traverseDirectory :: (s -> RawFilePath -> IO s) -> s -> RawFilePath -> IO s
-traverseDirectory act s0 topdir = toploop
-  where
-    toploop = do
-        isDir <- isDirectory <$> getFileStatus topdir
-        s' <- act s0 topdir
-        if isDir then actOnDirContents topdir s' loop
-                 else return s'
-    loop typ path acc = do
-        isDir <- case () of
-            () | typ == dtDir     -> return True
-               | typ == dtUnknown -> isDirectory <$> getFileStatus path
-               | otherwise        -> return False
-        if isDir
-          then act acc path >>= \acc' -> actOnDirContents path acc' loop
-          else act acc path
-
-actOnDirContents :: RawFilePath
-                 -> b
-                 -> (DirType -> RawFilePath -> b -> IO b)
-                 -> IO b
-actOnDirContents pathRelToTop b f =
-  modifyIOError ((`ioeSetFileName` (BS.unpack pathRelToTop)) .
-                 (`ioeSetLocation` "findBSTypRel")) $ do
-    bracket
-      (openDirStream pathRelToTop)
-      (Posix.closeDirStream)
-      (\dirp -> loop dirp b)
- where
-  loop dirp b' = do
-    (typ,e) <- readDirEnt dirp
-    if (e == "")
-      then return b'
-      else do
-          if (e == "." || e == "..")
-              then loop dirp b'
-              else f typ (pathRelToTop </> e) b' >>= loop dirp
-
-
-----------------------------------------------------------
--- dodgy stuff
-
-type CDir = ()
-type CDirent = ()
-
--- Posix doesn't export DirStream, so to re-use that type we need to use
--- unsafeCoerce.  It's just a newtype, so this is a legitimate usage.
--- ugly trick.
-unpackDirStream :: DirStream -> Ptr CDir
-unpackDirStream = unsafeCoerce
-
-packDirStream :: Ptr CDir -> DirStream
-packDirStream = unsafeCoerce
-
--- the __hscore_* functions are defined in the unix package.  We can import them and let
--- the linker figure it out.
-foreign import ccall unsafe "__hscore_readdir"
-  c_readdir  :: Ptr CDir -> Ptr (Ptr CDirent) -> IO CInt
-
-foreign import ccall unsafe "__hscore_free_dirent"
-  c_freeDirEnt  :: Ptr CDirent -> IO ()
-
-foreign import ccall unsafe "__hscore_d_name"
-  c_name :: Ptr CDirent -> IO CString
-
-foreign import ccall unsafe "__posixdir_d_type"
-  c_type :: Ptr CDirent -> IO DirType
-
-foreign import ccall "realpath"
-  c_realpath :: CString -> CString -> IO CString
-
-foreign import ccall unsafe "fdopendir"
-  c_fdopendir :: Posix.Fd -> IO (Ptr ())
-
-foreign import ccall unsafe "open"
-   c_open :: CString -> CInt -> Posix.CMode -> IO CInt
-
-----------------------------------------------------------
--- less dodgy but still lower-level
-
-
-readDirEnt :: DirStream -> IO (DirType, RawFilePath)
-readDirEnt (unpackDirStream -> dirp) =
-  alloca $ \ptr_dEnt  -> loop ptr_dEnt
- where
-  loop ptr_dEnt = do
-    resetErrno
-    r <- c_readdir dirp ptr_dEnt
-    if (r == 0)
-       then do
-         dEnt <- peek ptr_dEnt
-         if (dEnt == nullPtr)
-            then return (dtUnknown,BS.empty)
-            else do
-                 dName <- c_name dEnt >>= peekFilePath
-                 dType <- c_type dEnt
-                 c_freeDirEnt dEnt
-                 return (dType, dName)
-       else do
-         errno <- getErrno
-         if (errno == eINTR)
-            then loop ptr_dEnt
-            else do
-                 let (Errno eo) = errno
-                 if (eo == 0)
-                    then return (dtUnknown,BS.empty)
-                    else throwErrno "readDirEnt"
-
-
-getDirectoryContents :: RawFilePath -> IO [(DirType, RawFilePath)]
-getDirectoryContents path =
-  modifyIOError ((`ioeSetFileName` (BS.unpack path)) .
-                 (`ioeSetLocation` "System.Posix.Directory.Traversals.getDirectoryContents")) $ do
-    bracket
-      (PosixBS.openDirStream path)
-      PosixBS.closeDirStream
-      loop
- where
-  loop dirp = do
-     t@(_typ,e) <- readDirEnt dirp
-     if BS.null e then return [] else do
-       es <- loop dirp
-       return (t:es)
-
-
-fdOpendir :: Posix.Fd -> IO DirStream
-fdOpendir fd =
-    packDirStream <$> throwErrnoIfNull "fdOpendir" (c_fdopendir fd)
-
-
-getDirectoryContents' :: Posix.Fd -> IO [(DirType, RawFilePath)]
-getDirectoryContents' fd =
-    bracket
-      (fdOpendir fd)
-      PosixBS.closeDirStream
-      loop
- where
-  loop dirp = do
-     t@(_typ,e) <- readDirEnt dirp
-     if BS.null e then return [] else do
-       es <- loop dirp
-       return (t:es)
-
-
-open_  :: CString
-       -> Posix.OpenMode
-       -> [Flags]
-       -> Maybe Posix.FileMode
-       -> IO Posix.Fd
-open_ str how optional_flags maybe_mode = do
-    fd <- c_open str all_flags mode_w
-    return (Posix.Fd fd)
-  where
-    all_flags  = unionFlags $ optional_flags ++ [open_mode] ++ creat
-
-
-    (creat, mode_w) = case maybe_mode of
-                        Nothing -> ([],0)
-                        Just x  -> ([oCreat], x)
-
-    open_mode = case how of
-                   Posix.ReadOnly  -> oRdonly
-                   Posix.WriteOnly -> oWronly
-                   Posix.ReadWrite -> oRdwr
-
-
--- |Open and optionally create this file.  See 'System.Posix.Files'
--- for information on how to use the 'FileMode' type.
-openFd :: RawFilePath
-       -> Posix.OpenMode
-       -> [Flags]
-       -> Maybe Posix.FileMode
-       -> IO Posix.Fd
-openFd name how optional_flags maybe_mode =
-   withFilePath name $ \str ->
-     throwErrnoPathIfMinus1Retry "openFd" name $
-       open_ str how optional_flags maybe_mode
-
-
--- | return the canonicalized absolute pathname
---
--- like canonicalizePath, but uses realpath(3)
-realpath :: RawFilePath -> IO RawFilePath
-realpath inp = do
-    allocaBytes pathMax $ \tmp -> do
-        void $ BS.useAsCString inp $ \cstr -> throwErrnoIfNull "realpath" $ c_realpath cstr tmp
-        BS.packCString tmp

src/System/Posix/FilePath.hs

@@ -1,535 +0,0 @@
-{-# LANGUAGE TupleSections #-}
-
-{-# OPTIONS_GHC -Wall #-}
-
--- | The equivalent of "System.FilePath" on raw (byte string) file paths.
---
--- Not all functions of "System.FilePath" are implemented yet. Feel free to contribute!
-module System.Posix.FilePath (
-
-  pathSeparator
-, isPathSeparator
-, searchPathSeparator
-, isSearchPathSeparator
-, extSeparator
-, isExtSeparator
-
-, splitExtension
-, takeExtension
-, replaceExtension
-, dropExtension
-, addExtension
-, hasExtension
-, (<.>)
-, splitExtensions
-, dropExtensions
-, takeExtensions
-
-, splitFileName
-, takeFileName
-, replaceFileName
-, dropFileName
-, takeBaseName
-, replaceBaseName
-, takeDirectory
-, replaceDirectory
-, combine
-, (</>)
-, splitPath
-, joinPath
-, normalise
-, splitDirectories
-
-, hasTrailingPathSeparator
-, addTrailingPathSeparator
-, dropTrailingPathSeparator
-
-, isRelative
-, isAbsolute
-, isValid
-, equalFilePath
-
-, module System.Posix.ByteString.FilePath
-) where
-
-import           Data.ByteString (ByteString)
-import qualified Data.ByteString as BS
-import           System.Posix.ByteString.FilePath
-
-import           Data.Maybe (isJust)
-import           Data.Word8
-
-import           Control.Arrow (second)
-
--- $setup
--- >>> import Data.Char
--- >>> import Test.QuickCheck
--- >>> import Control.Applicative
--- >>> import qualified Data.ByteString as BS
--- >>> import Data.ByteString (ByteString)
--- >>> instance Arbitrary ByteString where arbitrary = BS.pack <$> arbitrary
--- >>> instance CoArbitrary ByteString where coarbitrary = coarbitrary . BS.unpack
---
--- >>> let _chr :: Word8 -> Char; _chr = chr . fromIntegral
-
-
--- | Path separator character
-pathSeparator :: Word8
-pathSeparator = _slash
-
--- | Check if a character is the path separator
---
--- prop> \n ->  (_chr n == '/') == isPathSeparator n
-isPathSeparator :: Word8 -> Bool
-isPathSeparator = (== pathSeparator)
-
--- | Search path separator
-searchPathSeparator :: Word8
-searchPathSeparator = _colon
-
--- | Check if a character is the search path separator
---
--- prop> \n -> (_chr n == ':') == isSearchPathSeparator n
-isSearchPathSeparator :: Word8 -> Bool
-isSearchPathSeparator = (== searchPathSeparator)
-
--- | File extension separator
-extSeparator :: Word8
-extSeparator = _period
-
--- | Check if a character is the file extension separator
---
--- prop> \n -> (_chr n == '.') == isExtSeparator n
-isExtSeparator :: Word8 -> Bool
-isExtSeparator = (== extSeparator)
-
-------------------------
--- extension stuff
-
--- | Split a 'RawFilePath' into a path+filename and extension
---
--- >>> splitExtension "file.exe"
--- ("file",".exe")
--- >>> splitExtension "file"
--- ("file","")
--- >>> splitExtension "/path/file.tar.gz"
--- ("/path/file.tar",".gz")
---
--- prop> \path -> uncurry (BS.append) (splitExtension path) == path
-splitExtension :: RawFilePath -> (RawFilePath, ByteString)
-splitExtension x = if BS.null basename
-    then (x,BS.empty)
-    else (BS.append path (BS.init basename),BS.cons extSeparator fileExt)
-  where
-    (path,file) = splitFileNameRaw x
-    (basename,fileExt) = BS.breakEnd isExtSeparator file
-
--- | Get the final extension from a 'RawFilePath'
---
--- >>> takeExtension "file.exe"
--- ".exe"
--- >>> takeExtension "file"
--- ""
--- >>> takeExtension "/path/file.tar.gz"
--- ".gz"
-takeExtension :: RawFilePath -> ByteString
-takeExtension = snd . splitExtension
-
--- | Change a file's extension
---
--- prop> \path -> let ext = takeExtension path in replaceExtension path ext == path
-replaceExtension :: RawFilePath -> ByteString -> RawFilePath
-replaceExtension path ext = dropExtension path <.> ext
-
--- | Drop the final extension from a 'RawFilePath'
---
--- >>> dropExtension "file.exe"
--- "file"
--- >>> dropExtension "file"
--- "file"
--- >>> dropExtension "/path/file.tar.gz"
--- "/path/file.tar"
-dropExtension :: RawFilePath -> RawFilePath
-dropExtension = fst . splitExtension
-
--- | Add an extension to a 'RawFilePath'
---
--- >>> addExtension "file" ".exe"
--- "file.exe"
--- >>> addExtension "file.tar" ".gz"
--- "file.tar.gz"
--- >>> addExtension "/path/" ".ext"
--- "/path/.ext"
-addExtension :: RawFilePath -> ByteString -> RawFilePath
-addExtension file ext
-    | BS.null ext = file
-    | isExtSeparator (BS.head ext) = BS.append file ext
-    | otherwise = BS.intercalate (BS.singleton extSeparator) [file, ext]
-
-
--- | Operator version of 'addExtension'
-(<.>) :: RawFilePath -> ByteString -> RawFilePath
-(<.>) = addExtension
-
--- | Check if a 'RawFilePath' has an extension
---
--- >>> hasExtension "file"
--- False
--- >>> hasExtension "file.tar"
--- True
--- >>> hasExtension "/path.part1/"
--- False
-hasExtension :: RawFilePath -> Bool
-hasExtension = isJust . BS.elemIndex extSeparator . takeFileName
-
--- | Split a 'RawFilePath' on the first extension
---
--- >>> splitExtensions "/path/file.tar.gz"
--- ("/path/file",".tar.gz")
---
--- prop> \path -> uncurry addExtension (splitExtensions path) == path
-splitExtensions :: RawFilePath -> (RawFilePath, ByteString)
-splitExtensions x = if BS.null basename
-    then (path,fileExt)
-    else (BS.append path basename,fileExt)
-  where
-    (path,file) = splitFileNameRaw x
-    (basename,fileExt) = BS.break isExtSeparator file
-
--- | Remove all extensions from a 'RawFilePath'
---
--- >>> dropExtensions "/path/file.tar.gz"
--- "/path/file"
-dropExtensions :: RawFilePath -> RawFilePath
-dropExtensions = fst . splitExtensions
-
--- | Take all extensions from a 'RawFilePath'
---
--- >>> takeExtensions "/path/file.tar.gz"
--- ".tar.gz"
-takeExtensions :: RawFilePath -> ByteString
-takeExtensions = snd . splitExtensions
-
-------------------------
--- more stuff
-
--- | Split a 'RawFilePath' into (path,file).  'combine' is the inverse
---
--- >>> splitFileName "path/file.txt"
--- ("path/","file.txt")
--- >>> splitFileName "path/"
--- ("path/","")
--- >>> splitFileName "file.txt"
--- ("./","file.txt")
---
--- prop> \path -> uncurry combine (splitFileName path) == path || fst (splitFileName path) == "./"
-splitFileName :: RawFilePath -> (RawFilePath, RawFilePath)
-splitFileName x = if BS.null path
-    then (dotSlash, file)
-    else (path,file)
-  where
-    (path,file) = splitFileNameRaw x
-    dotSlash = _period `BS.cons` (BS.singleton pathSeparator)
-
-
--- | Get the file name
---
--- >>> takeFileName "path/file.txt"
--- "file.txt"
--- >>> takeFileName "path/"
--- ""
-takeFileName :: RawFilePath -> RawFilePath
-takeFileName = snd . splitFileName
-
--- | Change the file name
---
--- prop> \path -> replaceFileName path (takeFileName path) == path
-replaceFileName :: RawFilePath -> ByteString -> RawFilePath
-replaceFileName x y = fst (splitFileNameRaw x) </> y
-
--- | Drop the file name
---
--- >>> dropFileName "path/file.txt"
--- "path/"
--- >>> dropFileName "file.txt"
--- "./"
-dropFileName :: RawFilePath -> RawFilePath
-dropFileName = fst . splitFileName
-
--- | Get the file name, without a trailing extension
---
--- >>> takeBaseName "path/file.tar.gz"
--- "file.tar"
--- >>> takeBaseName ""
--- ""
-takeBaseName :: RawFilePath -> ByteString
-takeBaseName = dropExtension . takeFileName
-
--- | Change the base name
---
--- >>> replaceBaseName "path/file.tar.gz" "bob"
--- "path/bob.gz"
---
--- prop> \path -> replaceBaseName path (takeBaseName path) == path
-replaceBaseName :: RawFilePath -> ByteString -> RawFilePath
-replaceBaseName path name = combineRaw dir (name <.> ext)
-  where
-    (dir,file) = splitFileNameRaw path
-    ext = takeExtension file
-
--- | Get the directory, moving up one level if it's already a directory
---
--- >>> takeDirectory "path/file.txt"
--- "path"
--- >>> takeDirectory "file"
--- "."
--- >>> takeDirectory "/path/to/"
--- "/path/to"
--- >>> takeDirectory "/path/to"
--- "/path"
-takeDirectory :: RawFilePath -> RawFilePath
-takeDirectory x = case () of
-    () | x == BS.singleton pathSeparator -> x
-       | BS.null res && not (BS.null file) -> file
-       | otherwise -> res
-  where
-    res = fst $ BS.spanEnd isPathSeparator file
-    file = dropFileName x
-
--- | Change the directory component of a 'RawFilePath'
---
--- prop> \path -> replaceDirectory path (takeDirectory path) `equalFilePath` path || takeDirectory path == "."
-replaceDirectory :: RawFilePath -> ByteString -> RawFilePath
-replaceDirectory file dir = combineRaw dir (takeFileName file)
-
--- | Join two paths together
---
--- >>> combine "/" "file"
--- "/file"
--- >>> combine "/path/to" "file"
--- "/path/to/file"
--- >>> combine "file" "/absolute/path"
--- "/absolute/path"
-combine :: RawFilePath -> RawFilePath -> RawFilePath
-combine a b | not (BS.null b) && isPathSeparator (BS.head b) = b
-            | otherwise = combineRaw a b
-
--- | Operator version of combine
-(</>) :: RawFilePath -> RawFilePath -> RawFilePath
-(</>) = combine
-
--- | Split a path into a list of components:
---
--- >>> splitPath "/path/to/file.txt"
--- ["/","path/","to/","file.txt"]
---
--- prop> \path -> BS.concat (splitPath path) == path
-splitPath :: RawFilePath -> [RawFilePath]
-splitPath = splitter
-  where
-    splitter x
-      | BS.null x = []
-      | otherwise = case BS.elemIndex pathSeparator x of
-            Nothing -> [x]
-            Just ix -> case BS.findIndex (not . isPathSeparator) $ BS.drop (ix+1) x of
-                          Nothing -> [x]
-                          Just runlen -> uncurry (:) . second splitter $ BS.splitAt (ix+1+runlen) x
-
--- | Like 'splitPath', but without trailing slashes
---
--- >>> splitDirectories "/path/to/file.txt"
--- ["/","path","to","file.txt"]
--- >>> splitDirectories ""
--- []
-splitDirectories :: RawFilePath -> [RawFilePath]
-splitDirectories x
-    | BS.null x = []
-    | isPathSeparator (BS.head x) = let (root,rest) = BS.splitAt 1 x
-                                    in root : splitter rest
-    | otherwise = splitter x
-  where
-    splitter = filter (not . BS.null) . BS.split pathSeparator
-
--- | Join a split path back together
---
--- prop> \path -> joinPath (splitPath path) == path
---
--- >>> joinPath ["path","to","file.txt"]
--- "path/to/file.txt"
-joinPath :: [RawFilePath] -> RawFilePath
-joinPath = foldr (</>) BS.empty
-
-
--- |Normalise a file.
---
--- >>> normalise "/file/\\test////"
--- "/file/\\test/"
--- >>> normalise "/file/./test"
--- "/file/test"
--- >>> normalise "/test/file/../bob/fred/"
--- "/test/file/../bob/fred/"
--- >>> normalise "../bob/fred/"
--- "../bob/fred/"
--- >>> normalise "./bob/fred/"
--- "bob/fred/"
--- >>> normalise "./bob////.fred/./...///./..///#."
--- "bob/.fred/.../../#."
--- >>> normalise "."
--- "."
--- >>> normalise "./"
--- "./"
--- >>> normalise "./."
--- "./"
--- >>> normalise "/./"
--- "/"
--- >>> normalise "/"
--- "/"
--- >>> normalise "bob/fred/."
--- "bob/fred/"
--- >>> normalise "//home"
--- "/home"
-normalise :: RawFilePath -> RawFilePath
-normalise filepath =
-  result `BS.append`
-  (if addPathSeparator
-       then BS.singleton pathSeparator
-       else BS.empty)
-  where
-    result = let n = f filepath
-             in if BS.null n
-                then BS.singleton _period
-                else n
-    addPathSeparator = isDirPath filepath &&
-      not (hasTrailingPathSeparator result)
-    isDirPath xs = hasTrailingPathSeparator xs
-        || not (BS.null xs) && BS.last xs == _period
-           && hasTrailingPathSeparator (BS.init xs)
-    f = joinPath . dropDots . propSep . splitDirectories
-    propSep :: [ByteString] -> [ByteString]
-    propSep (x:xs)
-      | BS.all (== pathSeparator) x = BS.singleton pathSeparator : xs
-      | otherwise                   = x : xs
-    propSep [] = []
-    dropDots :: [ByteString] -> [ByteString]
-    dropDots = filter (BS.singleton _period /=)
-
-
-------------------------
--- trailing path separators
-
--- | Check if the last character of a 'RawFilePath' is '/'.
---
--- >>> hasTrailingPathSeparator "/path/"
--- True
--- >>> hasTrailingPathSeparator "/"
--- True
--- >>> hasTrailingPathSeparator "/path"
--- False
-hasTrailingPathSeparator :: RawFilePath -> Bool
-hasTrailingPathSeparator x
-  | BS.null x = False
-  | otherwise = isPathSeparator $ BS.last x
-
--- | Add a trailing path separator.
---
--- >>> addTrailingPathSeparator "/path"
--- "/path/"
--- >>> addTrailingPathSeparator "/path/"
--- "/path/"
--- >>> addTrailingPathSeparator "/"
--- "/"
-addTrailingPathSeparator :: RawFilePath -> RawFilePath
-addTrailingPathSeparator x = if hasTrailingPathSeparator x
-    then x
-    else x `BS.snoc` pathSeparator
-
--- | Remove a trailing path separator
---
--- >>> dropTrailingPathSeparator "/path/"
--- "/path"
--- >>> dropTrailingPathSeparator "/path////"
--- "/path"
--- >>> dropTrailingPathSeparator "/"
--- "/"
--- >>> dropTrailingPathSeparator "//"
--- "/"
-dropTrailingPathSeparator :: RawFilePath -> RawFilePath
-dropTrailingPathSeparator x
-  | x == BS.singleton pathSeparator = x
-  | otherwise = if hasTrailingPathSeparator x
-                  then dropTrailingPathSeparator $ BS.init x
-                  else x
-
-------------------------
--- Filename/system stuff
-
--- | Check if a path is absolute
---
--- >>> isAbsolute "/path"
--- True
--- >>> isAbsolute "path"
--- False
--- >>> isAbsolute ""
--- False
-isAbsolute :: RawFilePath -> Bool
-isAbsolute x
-    | BS.length x > 0 = isPathSeparator (BS.head x)
-    | otherwise = False
-
--- | Check if a path is relative
---
--- prop> \path -> isRelative path /= isAbsolute path
-isRelative :: RawFilePath -> Bool
-isRelative = not . isAbsolute
-
--- | Is a FilePath valid, i.e. could you create a file like it?
---
--- >>> isValid ""
--- False
--- >>> isValid "\0"
--- False
--- >>> isValid "/random_ path:*"
--- True
-isValid :: RawFilePath -> Bool
-isValid filepath
-  | BS.null filepath        = False
-  | _nul `BS.elem` filepath = False
-  | otherwise               = True
-
--- |Equality of two filepaths. The filepaths are normalised
--- and trailing path separators are dropped.
---
--- >>> equalFilePath "foo" "foo"
--- True
--- >>> equalFilePath "foo" "foo/"
--- True
--- >>> equalFilePath "foo" "./foo"
--- True
--- >>> equalFilePath "foo" "/foo"
--- False
--- >>> equalFilePath "foo" "FOO"
--- False
--- >>> equalFilePath "foo" "../foo"
--- False
---
--- prop> \p -> equalFilePath p p
-equalFilePath :: RawFilePath -> RawFilePath -> Bool
-equalFilePath p1 p2 = f p1 == f p2
-  where
-    f x = dropTrailingPathSeparator $ normalise x
-
-------------------------
--- internal stuff
-
--- Just split the input FileName without adding/normalizing or changing
--- anything.
-splitFileNameRaw :: RawFilePath -> (RawFilePath, RawFilePath)
-splitFileNameRaw x = BS.breakEnd isPathSeparator x
-
--- | Combine two paths, assuming rhs is NOT absolute.
-combineRaw :: RawFilePath -> RawFilePath -> RawFilePath
-combineRaw a b | BS.null a = b
-                  | BS.null b = a
-                  | isPathSeparator (BS.last a) = BS.append a b
-                  | otherwise = BS.intercalate (BS.singleton pathSeparator) [a, b]
-

test/Main.hs

@@ -0,0 +1,225 @@
+{-# LANGUAGE TemplateHaskell #-}
+
+-- | Test suite.
+
+module Main where
+
+import Control.Applicative
+import Control.Monad
+import Data.Maybe
+import Data.Monoid
+import Path
+import Path.Internal
+import Test.Hspec
+
+-- | Test suite entry point, returns exit failure if any test fails.
+main :: IO ()
+main = hspec spec
+
+-- | Test suite.
+spec :: Spec
+spec =
+  do describe "Parsing: Path Abs Dir" parseAbsDirSpec
+     describe "Parsing: Path Rel Dir" parseRelDirSpec
+     describe "Parsing: Path Abs File" parseAbsFileSpec
+     describe "Parsing: Path Rel File" parseRelFileSpec
+     describe "Operations: (</>)" operationAppend
+     describe "Operations: stripDir" operationStripDir
+     describe "Operations: isParentOf" operationIsParentOf
+     describe "Operations: parent" operationParent
+     describe "Operations: filename" operationFilename
+     describe "Restrictions" restrictions
+
+-- | Restricting the input of any tricks.
+restrictions :: Spec
+restrictions =
+  do parseFails "~/"
+     parseFails "~/foo"
+     parseFails "~/foo/bar"
+     parseFails "../"
+     parseFails ".."
+     parseFails "."
+     parseFails "/.."
+     parseFails "/foo/../bar/"
+     parseFails "/foo/bar/.."
+  where parseFails x =
+          it (show x ++ " should be rejected")
+             (isNothing (void (parseAbsDir x) <|>
+                         void (parseRelDir x) <|>
+                         void (parseAbsFile x) <|>
+                         void (parseRelFile x)))
+
+-- | The 'filename' operation.
+operationFilename :: Spec
+operationFilename =
+  do it "filename ($(mkAbsDir parent) </> filename $(mkRelFile filename)) == $(mkRelFile filename)"
+        (filename ($(mkAbsDir "/home/chris/") </>
+                   filename $(mkRelFile "bar.txt")) ==
+         $(mkRelFile "bar.txt"))
+     it "filename ($(mkRelDir parent) </> filename $(mkRelFile filename)) == $(mkRelFile filename)"
+        (filename ($(mkRelDir "home/chris/") </>
+                   filename $(mkRelFile "bar.txt")) ==
+         $(mkRelFile "bar.txt"))
+
+-- | The 'parent' operation.
+operationParent :: Spec
+operationParent =
+  do it "parent (parent </> child) == parent"
+        (parent ($(mkAbsDir "/foo") </>
+                    $(mkRelDir "bar")) ==
+         $(mkAbsDir "/foo"))
+     it "parent \"\" == \"\""
+        (parent $(mkAbsDir "/") ==
+         $(mkAbsDir "/"))
+     it "parent (parent \"\") == \"\""
+        (parent (parent $(mkAbsDir "/")) ==
+         $(mkAbsDir "/"))
+
+-- | The 'isParentOf' operation.
+operationIsParentOf :: Spec
+operationIsParentOf =
+  do it "isParentOf parent (parent </> child)"
+        (isParentOf
+           $(mkAbsDir "///bar/")
+           ($(mkAbsDir "///bar/") </>
+            $(mkRelFile "bar/foo.txt")))
+     it "isParentOf parent (parent </> child)"
+        (isParentOf
+           $(mkRelDir "bar/")
+           ($(mkRelDir "bar/") </>
+            $(mkRelFile "bob/foo.txt")))
+
+-- | The 'stripDir' operation.
+operationStripDir :: Spec
+operationStripDir =
+  do it "stripDir parent (parent </> child) = child"
+        (stripDir $(mkAbsDir "///bar/")
+                  ($(mkAbsDir "///bar/") </>
+                   $(mkRelFile "bar/foo.txt")) ==
+         Just $(mkRelFile "bar/foo.txt"))
+     it "stripDir parent (parent </> child) = child"
+        (stripDir $(mkRelDir "bar/")
+                  ($(mkRelDir "bar/") </>
+                   $(mkRelFile "bob/foo.txt")) ==
+         Just $(mkRelFile "bob/foo.txt"))
+     it "stripDir parent parent = _|_"
+        (stripDir $(mkAbsDir "/home/chris/foo")
+                  $(mkAbsDir "/home/chris/foo") ==
+         Nothing)
+
+-- | The '</>' operation.
+operationAppend :: Spec
+operationAppend =
+  do it "AbsDir + RelDir = AbsDir"
+        ($(mkAbsDir "/home/") </>
+         $(mkRelDir "chris") ==
+         $(mkAbsDir "/home/chris/"))
+     it "AbsDir + RelFile = AbsFile"
+        ($(mkAbsDir "/home/") </>
+         $(mkRelFile "chris/test.txt") ==
+         $(mkAbsFile "/home/chris/test.txt"))
+     it "RelDir + RelDir = RelDir"
+        ($(mkRelDir "home/") </>
+         $(mkRelDir "chris") ==
+         $(mkRelDir "home/chris"))
+     it "RelDir + RelFile = RelFile"
+        ($(mkRelDir "home/") </>
+         $(mkRelFile "chris/test.txt") ==
+         $(mkRelFile "home/chris/test.txt"))
+
+-- | Tests for the tokenizer.
+parseAbsDirSpec :: Spec
+parseAbsDirSpec =
+  do failing ""
+     failing "./"
+     failing "~/"
+     failing "foo.txt"
+     succeeding "/" (Path "/")
+     succeeding "//" (Path "/")
+     succeeding "///foo//bar//mu/" (Path "/foo/bar/mu/")
+     succeeding "///foo//bar////mu" (Path "/foo/bar/mu/")
+     succeeding "///foo//bar/.//mu" (Path "/foo/bar/mu/")
+  where failing x = parserTest parseAbsDir x Nothing
+        succeeding x with = parserTest parseAbsDir x (Just with)
+
+-- | Tests for the tokenizer.
+parseRelDirSpec :: Spec
+parseRelDirSpec =
+  do failing ""
+     failing "/"
+     failing "//"
+     failing "~/"
+     failing "/"
+     failing "./"
+     failing "././"
+     failing "//"
+     failing "///foo//bar//mu/"
+     failing "///foo//bar////mu"
+     failing "///foo//bar/.//mu"
+     succeeding "..." (Path ".../")
+     succeeding "foo.bak" (Path "foo.bak/")
+     succeeding "./foo" (Path "foo/")
+     succeeding "././foo" (Path "foo/")
+     succeeding "./foo/./bar" (Path "foo/bar/")
+     succeeding "foo//bar//mu//" (Path "foo/bar/mu/")
+     succeeding "foo//bar////mu" (Path "foo/bar/mu/")
+     succeeding "foo//bar/.//mu" (Path "foo/bar/mu/")
+  where failing x = parserTest parseRelDir x Nothing
+        succeeding x with = parserTest parseRelDir x (Just with)
+
+-- | Tests for the tokenizer.
+parseAbsFileSpec :: Spec
+parseAbsFileSpec =
+  do failing ""
+     failing "./"
+     failing "~/"
+     failing "./foo.txt"
+     failing "/"
+     failing "//"
+     failing "///foo//bar//mu/"
+     succeeding "/..." (Path "/...")
+     succeeding "/foo.txt" (Path "/foo.txt")
+     succeeding "///foo//bar////mu.txt" (Path "/foo/bar/mu.txt")
+     succeeding "///foo//bar/.//mu.txt" (Path "/foo/bar/mu.txt")
+  where failing x = parserTest parseAbsFile x Nothing
+        succeeding x with = parserTest parseAbsFile x (Just with)
+
+-- | Tests for the tokenizer.
+parseRelFileSpec :: Spec
+parseRelFileSpec =
+  do failing ""
+     failing "/"
+     failing "//"
+     failing "~/"
+     failing "/"
+     failing "./"
+     failing "//"
+     failing "///foo//bar//mu/"
+     failing "///foo//bar////mu"
+     failing "///foo//bar/.//mu"
+     succeeding "..." (Path "...")
+     succeeding "foo.txt" (Path "foo.txt")
+     succeeding "./foo.txt" (Path "foo.txt")
+     succeeding "././foo.txt" (Path "foo.txt")
+     succeeding "./foo/./bar.txt" (Path "foo/bar.txt")
+     succeeding "foo//bar//mu.txt" (Path "foo/bar/mu.txt")
+     succeeding "foo//bar////mu.txt" (Path "foo/bar/mu.txt")
+     succeeding "foo//bar/.//mu.txt" (Path "foo/bar/mu.txt")
+  where failing x = parserTest parseRelFile x Nothing
+        succeeding x with = parserTest parseRelFile x (Just with)
+
+-- | Parser test.
+parserTest :: (Show a1,Show a,Eq a1)
+           => (a -> Maybe a1) -> a -> Maybe a1 -> SpecWith ()
+parserTest parser input expected =
+  it ((case expected of
+         Nothing -> "Failing: "
+         Just{} -> "Succeeding: ") <>
+      "Parsing " <>
+      show input <>
+      " " <>
+      case expected of
+        Nothing -> "should fail."
+        Just x -> "should succeed with: " <> show x)
+     (actual == expected)
+  where actual = parser input