mcs/class/Mono.Posix/Mono.Unix/UnixPath.cs

   1 //
   2 // Mono.Unix/UnixPath.cs
   3 //
   4 // Authors:
   5 //   Jonathan Pryor (jonpryor@vt.edu)
   6 //
   7 // (C) 2004-2006 Jonathan Pryor
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 using System;
  30 using System.Collections;
  31 using System.Text;
  32 using Mono.Unix;
  33
  34 namespace Mono.Unix {
  35
  36         public sealed class UnixPath
  37         {
  38                 private UnixPath () {}
  39
  40                 public static readonly char DirectorySeparatorChar = '/';
  41                 public static readonly char AltDirectorySeparatorChar = '/';
  42                 [Obsolete ("Use GetInvalidPathChars()")]
  43                 public static readonly char[] InvalidPathChars = new char[]{};
  44                 public static readonly char PathSeparator = ':';
  45                 public static readonly char VolumeSeparatorChar = '/';
  46
  47                 private static readonly char[] _InvalidPathChars = new char[]{};
  48
  49                 public static char[] GetInvalidPathChars ()
  50                 {
  51                         return (char[]) _InvalidPathChars.Clone ();
  52                 }
  53
  54                 public static string Combine (string path1, params string[] paths)
  55                 {
  56                         if (path1 == null)
  57                                 throw new ArgumentNullException ("path1");
  58                         if (paths == null)
  59                                 throw new ArgumentNullException ("paths");
  60                         if (path1.IndexOfAny (_InvalidPathChars) != -1)
  61                                 throw new ArgumentException ("Illegal characters in path", "path1");
  62
  63                         int len = path1.Length + 1;
  64                         for (int i = 0; i < paths.Length; ++i) {
  65                                 if (paths [i] == null)
  66                                         throw new ArgumentNullException ("paths");
  67                                 len += paths [i].Length + 1;
  68                         }
  69
  70                         StringBuilder sb = new StringBuilder (len);
  71                         sb.Append (path1);
  72                         for (int i = 0; i < paths.Length; ++i)
  73                                 Combine (sb, paths [i]);
  74                         return sb.ToString ();
  75                 }
  76
  77                 private static void Combine (StringBuilder path, string part)
  78                 {
  79                         if (part.IndexOfAny (_InvalidPathChars) != -1)
  80                                 throw new ArgumentException ("Illegal characters in path", "path1");
  81                         char end = path [path.Length-1];
  82                         if (end != DirectorySeparatorChar &&
  83                                         end != AltDirectorySeparatorChar &&
  84                                         end != VolumeSeparatorChar)
  85                                 path.Append (DirectorySeparatorChar);
  86                         path.Append (part);
  87                 }
  88
  89                 public static string GetDirectoryName (string path)
  90                 {
  91                         CheckPath (path);
  92
  93                         int lastDir = path.LastIndexOf (DirectorySeparatorChar);
  94                         if (lastDir > 0)
  95                                 return path.Substring (0, lastDir);
  96                         return "";
  97                 }
  98
  99                 public static string GetFileName (string path)
 100                 {
 101                         if (path == null || path.Length == 0)
 102                                 return path;
 103
 104                         int lastDir = path.LastIndexOf (DirectorySeparatorChar);
 105                         if (lastDir >= 0)
 106                                 return path.Substring (lastDir+1);
 107
 108                         return path;
 109                 }
 110
 111                 public static string GetFullPath (string path)
 112                 {
 113                         path = _GetFullPath (path);
 114                         return GetCanonicalPath (path);
 115                 }
 116
 117                 private static string _GetFullPath (string path)
 118                 {
 119                         if (path == null)
 120                                 throw new ArgumentNullException ("path");
 121                         if (!IsPathRooted (path))
 122                                 path = UnixDirectoryInfo.GetCurrentDirectory() + DirectorySeparatorChar + path;
 123
 124                         return path;
 125                 }
 126
 127                 public static string GetCanonicalPath (string path)
 128                 {
 129                         string [] dirs;
 130                         int lastIndex;
 131                         GetPathComponents (path, out dirs, out lastIndex);
 132                         string end = string.Join ("/", dirs, 0, lastIndex);
 133                         return IsPathRooted (path) ? "/" + end : end;
 134                 }
 135
 136                 private static void GetPathComponents (string path,
 137                         out string[] components, out int lastIndex)
 138                 {
 139                         string [] dirs = path.Split (DirectorySeparatorChar);
 140                         int target = 0;
 141                         for (int i = 0; i < dirs.Length; ++i) {
 142                                 if (dirs [i] == "." || dirs [i] == string.Empty) continue;
 143                                 else if (dirs [i] == "..") {
 144                                         if (target != 0) --target;
 145                                         else ++target;
 146                                 }
 147                                 else
 148                                         dirs [target++] = dirs [i];
 149                         }
 150                         components = dirs;
 151                         lastIndex = target;
 152                 }
 153
 154                 public static string GetPathRoot (string path)
 155                 {
 156                         if (path == null)
 157                                 return null;
 158                         if (!IsPathRooted (path))
 159                                 return "";
 160                         return "/";
 161                 }
 162
 163                 public static string GetCompleteRealPath (string path)
 164                 {
 165                         if (path == null)
 166                                 throw new ArgumentNullException ("path");
 167                         string [] dirs;
 168                         int lastIndex;
 169                         GetPathComponents (path, out dirs, out lastIndex);
 170                         StringBuilder realPath = new StringBuilder ();
 171                         if (dirs.Length > 0) {
 172                                 string dir = IsPathRooted (path) ? "/" : "";
 173                                 dir += dirs [0];
 174                                 realPath.Append (GetRealPath (dir));
 175                         }
 176                         for (int i = 1; i < lastIndex; ++i) {
 177                                 realPath.Append ("/").Append (dirs [i]);
 178                                 string p = GetRealPath (realPath.ToString());
 179                                 realPath.Remove (0, realPath.Length);
 180                                 realPath.Append (p);
 181                         }
 182                         return realPath.ToString ();
 183                 }
 184
 185                 public static string GetRealPath (string path)
 186                 {
 187                         do {
 188                                 string name = ReadSymbolicLink (path);
 189                                 if (name == null)
 190                                         return path;
 191                                 if (IsPathRooted (name))
 192                                         path = name;
 193                                 else {
 194                                         path = GetDirectoryName (path) + DirectorySeparatorChar + name;
 195                                         path = GetCanonicalPath (path);
 196                                 }
 197                         } while (true);
 198                 }
 199
 200                 // Read the specified symbolic link.  If the file isn't a symbolic link,
 201                 // return null; otherwise, return the contents of the symbolic link.
 202                 //
 203                 // readlink(2) is horribly evil, as there is no way to query how big the
 204                 // symlink contents are.  Consequently, it's trial and error...
 205                 internal static string ReadSymbolicLink (string path)
 206                 {
 207                         StringBuilder buf = new StringBuilder (256);
 208                         do {
 209                                 int r = Native.Syscall.readlink (path, buf);
 210                                 if (r < 0) {
 211                                         Native.Errno e;
 212                                         switch (e = Native.Stdlib.GetLastError()) {
 213                                         case Native.Errno.EINVAL:
 214                                                 // path isn't a symbolic link
 215                                                 return null;
 216                                         default:
 217                                                 UnixMarshal.ThrowExceptionForError (e);
 218                                                 break;
 219                                         }
 220                                 }
 221                                 else if (r == buf.Capacity) {
 222                                         buf.Capacity *= 2;
 223                                 }
 224                                 else
 225                                         return buf.ToString (0, r);
 226                         } while (true);
 227                 }
 228
 229                 public static bool IsPathRooted (string path)
 230                 {
 231                         if (path == null || path.Length == 0)
 232                                 return false;
 233                         return path [0] == DirectorySeparatorChar;
 234                 }
 235
 236                 internal static void CheckPath (string path)
 237                 {
 238                         if (path == null)
 239                                 throw new ArgumentNullException ();
 240                         if (path.Length == 0)
 241                                 throw new ArgumentException ("Path cannot contain a zero-length string", "path");
 242                         if (path.IndexOfAny (_InvalidPathChars) != -1)
 243                                 throw new ArgumentException ("Invalid characters in path.", "path");
 244                 }
 245         }
 246 }
 247
 248 // vim: noexpandtab