Implement getFileInfo to retrieve meta data

getFileInfo returns a record containing meta data about the given file,
such as permissions, last modification time and time. We'll use this
action to fill a neat status bar.

hcat.cabal

@@ -18,6 +18,7 @@ extra-source-files:
 library
   exposed-modules:
       HCat
+      HCat.FileInfo
       HCat.Internal
   other-modules:
       Paths_hcat
@@ -30,8 +31,10 @@ library
   ghc-options: -Wall -fdefer-typed-holes
   build-depends:
       base >=4.13 && <5
+    , directory
     , process
     , text
+    , time
   default-language: GHC2021
 
 executable hcat
@@ -47,7 +50,9 @@ executable hcat
   ghc-options: -Wall -fdefer-typed-holes
   build-depends:
       base >=4.13 && <5
+    , directory
     , hcat
+    , time
   default-language: GHC2021
 
 test-suite doctest
@@ -66,7 +71,9 @@ test-suite doctest
       doctest:doctest
   build-depends:
       base >=4.13 && <5
+    , directory
     , process
+    , time
   default-language: Haskell2010
 
 test-suite spec
@@ -88,7 +95,9 @@ test-suite spec
   build-depends:
       QuickCheck
     , base >=4.13 && <5
+    , directory
     , hcat
     , hspec
     , quickcheck-instances
+    , time
   default-language: GHC2021

package.yaml

@@ -11,9 +11,9 @@ extra-source-files:
 
 dependencies:
   - base >= 4.13 && < 5
+  - time
+  - directory
 #  - bytestring
-#  - time
-#  - directory
 
 ghc-options:
   - -Wall

src/HCat/FileInfo.hs

@@ -0,0 +1,45 @@
+{-# LANGUAGE RecordWildCards #-}
+
+-- | FileInfo defines a data type that captures important information about a
+-- file such as timestamps and permissions.
+module HCat.FileInfo (FileInfo, getFileInfo) where
+
+import Data.Text (Text)
+import Data.Text qualified as T
+
+import Data.Time.Clock (UTCTime)
+
+import System.Directory (getFileSize, getModificationTime, getPermissions)
+import System.Directory qualified as Directory
+
+data FileInfo = FileInfo
+  { filePath :: Text
+  , fileSize :: Integer
+  , fileMTime :: UTCTime
+  , fileReadable :: Bool
+  , fileWritable :: Bool
+  , fileExecutable :: Bool
+  }
+  deriving (Show)
+
+-- | @getFileInfo@ retrieves several meta data about the given file.
+--
+-- >>> info <- getFileInfo "src/HCat/FileInfo.hs"
+-- >>> filePath info
+-- "src/HCat/FileInfo.hs"
+-- >>> fileSize info > 0
+-- True
+-- >>> fileReadable info
+-- True
+-- >>> fileExecutable info
+-- False
+getFileInfo :: FilePath -> IO FileInfo
+getFileInfo path = do
+  perms <- getPermissions path
+  fileSize <- getFileSize path
+  fileMTime <- getModificationTime path
+  let fileReadable = Directory.readable perms
+      fileWritable = Directory.writable perms
+      fileExecutable = Directory.executable perms
+      filePath = T.pack path
+  return FileInfo{..}