1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
--------------------------------------------------------------------------------
--- Some utilities for deailing with files and directories
--- for the Curry Package Manager.
--------------------------------------------------------------------------------

module CPM.FileUtil
  ( joinSearchPath
  , copyDirectory
  , createSymlink
  , removeSymlink
  , isSymlink
  , linkTarget
  , copyDirectoryFollowingSymlinks
  , quote
  , tempDir
  , cleanTempDir
  , inTempDir
  , inDirectory
  , recreateDirectory
  , removeDirectoryComplete
  , safeReadFile, checkAndGetVisibleDirectoryContents
  , whenFileExists, ifFileExists
  ) where

import System.Directory   ( doesFileExist, doesDirectoryExist
                          , setCurrentDirectory, getDirectoryContents
                          , getTemporaryDirectory, doesDirectoryExist
                          , createDirectory, createDirectoryIfMissing
                          , getAbsolutePath, getCurrentDirectory )
import System.Process     ( system, exitWith, getPID )
import System.Environment ( getEnv )
import System.FilePath    ( FilePath, replaceFileName, (</>)
                          , searchPathSeparator )
import Data.List          ( intercalate, isPrefixOf, splitOn )
import Control.Monad      ( when )
import System.IOExts      ( evalCmd, readCompleteFile )

--- Joins a list of directories into a search path.
joinSearchPath :: [FilePath] -> String
joinSearchPath = intercalate [searchPathSeparator] . map emptyPath2Dot
 where
  emptyPath2Dot p = if null p then "." else p

--- Recursively copies a directory structure.
copyDirectory :: String -> String -> IO ()
copyDirectory src dst = do
  retCode <- system $ "cp -pR \"" ++ src ++ "\" \"" ++ dst ++ "\""
  if retCode /= 0
    then error $ "Copy failed with " ++ (show retCode)
    else return ()

--- Recursively copies a directory structure following symlinks, i.e. links
--- get replaced by copies in the destination.
copyDirectoryFollowingSymlinks :: String -> String -> IO ()
copyDirectoryFollowingSymlinks src dst = do
  retCode <- system $ "cp -pLR \"" ++ src ++ "\" \"" ++ dst ++ "\""
  if retCode /= 0
    then error $ "Copy failed with " ++ (show retCode)
    else return ()

--- Creates a new symlink.
createSymlink :: String -> String -> IO Int
createSymlink from to = system $ "ln -s " ++ (quote from) ++ " " ++ (quote to)

--- Deletes a symlink.
removeSymlink :: String -> IO Int
removeSymlink link = system $ "rm " ++ quote link

--- Tests whether a file is a symlink.
isSymlink :: String -> IO Bool
isSymlink link = do
  (code, _, _) <- evalCmd "readlink" ["-n", link] ""
  return $ code == 0

--- Gets the target of a symlink.
linkTarget :: String -> IO String
linkTarget link = do
  (rc, out, _) <- evalCmd "readlink" ["-n", link] ""
  if rc == 0
    then return $ replaceFileName link out
    else return ""

--- Puts a file argument into quotes to avoid problems with files containing
--- blanks.
quote :: String -> String
quote s = "\"" ++ s ++ "\""

--- Gets a temporary directory for some CPM command.
tempDir :: IO String
tempDir = do
  t   <- getTemporaryDirectory
  pid <- getPID
  return (t </> "cpm" ++ show pid)

--- Removes the temporary directory for some CPM command.
cleanTempDir :: IO ()
cleanTempDir = tempDir >>= removeDirectoryComplete

--- Executes an IO action with the current directory set to  CPM's temporary
--- directory.
inTempDir :: IO b -> IO b
inTempDir b = do
  t <- tempDir
  exists <- doesDirectoryExist t
  if exists
    then return ()
    else createDirectory t
  inDirectory t b

--- Executes an IO action with the current directory set to a specific
--- directory.
inDirectory :: String -> IO b -> IO b
inDirectory dir b = do
  previous <- getCurrentDirectory
  setCurrentDirectory dir
  b' <- b
  setCurrentDirectory previous
  return b'

--- Recreates a directory. Deletes its contents if it already exists.
recreateDirectory :: String -> IO ()
recreateDirectory dir = do
  removeDirectoryComplete dir
  createDirectoryIfMissing True dir

--- Deletes a directory and its contents, if it exists, otherwise nothing
--- is done.
removeDirectoryComplete :: String -> IO ()
removeDirectoryComplete dir = do
  exists <- doesDirectoryExist dir
  when exists $ system ("rm -Rf " ++ quote dir) >> return ()

--- Reads the complete contents of a file and catches any error
--- (which is returned).
safeReadFile :: String -> IO (Either IOError String)
safeReadFile fname = do
  catch (readCompleteFile fname >>= return . Right)
        (return . Left)

--- Returns the list of all entries in a directory and terminates with
--- an error message if the directory does not exist.
checkAndGetDirectoryContents :: FilePath -> IO [FilePath]
checkAndGetDirectoryContents dir = do
  exdir <- doesDirectoryExist dir
  if exdir then getDirectoryContents dir
           else do putStrLn $ "ERROR: Directory '" ++ dir ++ "' does not exist!"
                   exitWith 1

--- Returns the list of all visible entries in a directory (i.e., not starting
--- with '.') and terminates with an error message if the directory
--- does not exist.
checkAndGetVisibleDirectoryContents :: FilePath -> IO [FilePath]
checkAndGetVisibleDirectoryContents dir =
  checkAndGetDirectoryContents dir >>= return . filter (not . isPrefixOf ".")

--- Performs an action when a file exists.
whenFileExists :: FilePath -> IO () -> IO ()
whenFileExists fname act = do
  exfile <- doesFileExist fname
  when exfile act

--- Performs one of two actions depending on the existence of a file.
ifFileExists :: FilePath -> IO a -> IO a -> IO a
ifFileExists fname thenact elseact = do
  exfile <- doesFileExist fname
  if exfile then thenact else elseact