From 6a1f80bc17bfc9debccde0b3d7a2b684775d0f61 Mon Sep 17 00:00:00 2001
From: Julian Ospald <hasufell@posteo.de>
Date: Mon, 13 Jan 2020 23:12:55 +0100
Subject: [PATCH] Move file check functions to HPath.IO

---
 hpath-io/hpath-io.cabal         |  1 -
 hpath-io/src/HPath/IO.hs        | 84 ++++++++++++++++++++++++++++++++-
 hpath-io/src/HPath/IO.hs-boot   |  8 ++++
 hpath-io/src/HPath/IO/Errors.hs | 44 ++---------------
 4 files changed, 94 insertions(+), 43 deletions(-)

diff --git a/hpath-io/hpath-io.cabal b/hpath-io/hpath-io.cabal
index 1f02815..4072b96 100644
--- a/hpath-io/hpath-io.cabal
+++ b/hpath-io/hpath-io.cabal
@@ -73,7 +73,6 @@ test-suite spec
                         HPath.IO.GetFileTypeSpec
                         HPath.IO.MoveFileOverwriteSpec
                         HPath.IO.MoveFileSpec
-                        HPath.IO.ReadFileEOFSpec
                         HPath.IO.ReadFileSpec
                         HPath.IO.RecreateSymlinkOverwriteSpec
                         HPath.IO.RecreateSymlinkSpec
diff --git a/hpath-io/src/HPath/IO.hs b/hpath-io/src/HPath/IO.hs
index ff6826d..c6ef399 100644
--- a/hpath-io/src/HPath/IO.hs
+++ b/hpath-io/src/HPath/IO.hs
@@ -73,6 +73,12 @@ module HPath.IO
   -- * File permissions
   , newFilePerms
   , newDirPerms
+  -- * File checks
+  , doesExist
+  , doesFileExist
+  , doesDirectoryExist
+  , isWritable
+  , canOpenDirectory
   -- * Directory reading
   , getDirsFiles
   -- * Filetype operations
@@ -191,7 +197,9 @@ import System.Posix.ByteString
 import System.Posix.Directory.ByteString
   (
     createDirectory
+  , closeDirStream
   , getWorkingDirectory
+  , openDirStream
   , removeDirectory
   )
 import System.Posix.Directory.Traversals
@@ -201,6 +209,7 @@ import System.Posix.Directory.Traversals
 import System.Posix.Files.ByteString
   (
     createSymbolicLink
+  , fileAccess
   , fileMode
   , getFdStatus
   , groupExecuteMode
@@ -446,7 +455,9 @@ recreateSymlink symsource@(MkPath symsourceBS) newsym@(MkPath newsymBS) cm
     case cm of
       Strict -> return ()
       Overwrite -> do
-        writable <- toAbs newsym >>= isWritable
+        writable <- toAbs newsym >>= (\p -> do
+                                        e <- doesExist p
+                                        if e then isWritable p else pure False)
         isfile   <- doesFileExist newsym
         isdir    <- doesDirectoryExist newsym
         when (writable && isfile) (deleteFile newsym)
@@ -830,7 +841,10 @@ moveFile from to cm = do
                 easyDelete from
     Overwrite -> do
       ft <- getFileType from
-      writable <- toAbs to >>= isWritable
+      writable <- toAbs to >>= (\p -> do
+                                      e <- doesFileExist p
+                                      if e then isWritable p else pure False)
+
       case ft of
         RegularFile -> do
           exists <- doesFileExist to
@@ -980,6 +994,72 @@ newDirPerms
 
 
 
+
+    -------------------
+    --[ 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 (MkPath bs) =
+  catchErrno [eNOENT] (do
+      _  <- PF.getSymbolicLinkStatus bs
+      return $ True)
+    $ return False
+
+
+-- |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 (MkPath bs) =
+  catchErrno [eNOENT] (do
+      fs  <- PF.getSymbolicLinkStatus bs
+      return $ not . PF.isDirectory $ fs)
+    $ return False
+
+
+-- |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 (MkPath bs) =
+  catchErrno [eNOENT] (do
+      fs  <- PF.getSymbolicLinkStatus bs
+      return $ PF.isDirectory fs)
+    $ return False
+
+
+-- |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 (MkPath bs) = fileAccess bs False True False
+
+
+-- |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 (MkPath bs) =
+  handleIOError (\_ -> return False) $ do
+    bracket (openDirStream bs)
+            closeDirStream
+            (\_ -> return ())
+    return True
+
+
+
+
     -------------------------
     --[ Directory reading ]--
     -------------------------
diff --git a/hpath-io/src/HPath/IO.hs-boot b/hpath-io/src/HPath/IO.hs-boot
index d16bf75..bee74f5 100644
--- a/hpath-io/src/HPath/IO.hs-boot
+++ b/hpath-io/src/HPath/IO.hs-boot
@@ -6,3 +6,11 @@ import HPath
 canonicalizePath :: Path b -> IO (Path Abs)
 
 toAbs :: Path b -> IO (Path Abs)
+
+doesFileExist :: Path b -> IO Bool
+
+doesDirectoryExist :: Path b -> IO Bool
+
+isWritable :: Path b -> IO Bool
+
+canOpenDirectory :: Path b -> IO Bool
diff --git a/hpath-io/src/HPath/IO/Errors.hs b/hpath-io/src/HPath/IO/Errors.hs
index f6ef440..4668c52 100644
--- a/hpath-io/src/HPath/IO/Errors.hs
+++ b/hpath-io/src/HPath/IO/Errors.hs
@@ -33,10 +33,6 @@ module HPath.IO.Errors
   , throwSameFile
   , sameFile
   , throwDestinationInSource
-  , doesFileExist
-  , doesDirectoryExist
-  , isWritable
-  , canOpenDirectory
 
   -- * Error handling functions
   , catchErrno
@@ -92,6 +88,10 @@ import {-# SOURCE #-} HPath.IO
   (
     canonicalizePath
   , toAbs
+  , doesFileExist
+  , doesDirectoryExist
+  , isWritable
+  , canOpenDirectory
   )
 import System.IO.Error
   (
@@ -242,42 +242,6 @@ throwDestinationInSource (MkPath sbs) dest@(MkPath dbs) = do
        (throwIO $ DestinationInSource dbs sbs)
 
 
--- |Checks if the given file exists and is not a directory.
--- Does not follow symlinks.
-doesFileExist :: Path b -> IO Bool
-doesFileExist (MkPath bs) =
-  handleIOError (\_ -> return False) $ do
-    fs  <- PF.getSymbolicLinkStatus bs
-    return $ not . PF.isDirectory $ fs
-
-
--- |Checks if the given file exists and is a directory.
--- Does not follow symlinks.
-doesDirectoryExist :: Path b -> IO Bool
-doesDirectoryExist (MkPath bs) =
-  handleIOError (\_ -> return False) $ do
-    fs  <- PF.getSymbolicLinkStatus bs
-    return $ PF.isDirectory fs
-
-
--- |Checks whether a file or folder is writable.
-isWritable :: Path b -> IO Bool
-isWritable (MkPath bs) =
-  handleIOError (\_ -> return False) $
-    fileAccess bs False True False
-
-
--- |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 (MkPath bs) =
-  handleIOError (\_ -> return False) $ do
-    bracket (PFD.openDirStream bs)
-            PFD.closeDirStream
-            (\_ -> return ())
-    return True
-
-
 
 
     --------------------------------