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 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                 public static readonly char[] InvalidPathChars = new char[]{'\0'};
  43                 public static readonly char PathSeparator = ':';
  44                 public static readonly char VolumeSeparatorChar = '/';
  45
  46                 public static string Combine (string path1, params string[] paths)
  47                 {
  48                         if (path1 == null)
  49                                 throw new ArgumentNullException ("path1");
  50                         if (paths == null)
  51                                 throw new ArgumentNullException ("paths");
  52                         if (path1.IndexOfAny (InvalidPathChars) != -1)
  53                                 throw new ArgumentException ("Illegal characters in path", "path1");
  54
  55                         int len = path1.Length + 1;
  56                         for (int i = 0; i < paths.Length; ++i) {
  57                                 if (paths [i] == null)
  58                                         throw new ArgumentNullException ("paths");
  59                                 len += paths [i].Length + 1;
  60                         }
  61
  62                         StringBuilder sb = new StringBuilder (len);
  63                         sb.Append (path1);
  64                         for (int i = 0; i < paths.Length; ++i)
  65                                 Combine (sb, paths [i]);
  66                         return sb.ToString ();
  67                 }
  68
  69                 private static void Combine (StringBuilder path, string part)
  70                 {
  71                         if (part.IndexOfAny (InvalidPathChars) != -1)
  72                                 throw new ArgumentException ("Illegal characters in path", "path1");
  73                         char end = path [path.Length-1];
  74                         if (end != DirectorySeparatorChar &&
  75                                         end != AltDirectorySeparatorChar &&
  76                                         end != VolumeSeparatorChar)
  77                                 path.Append (DirectorySeparatorChar);
  78                         path.Append (part);
  79                 }
  80
  81                 public static string GetDirectoryName (string path)
  82                 {
  83                         CheckPath (path);
  84
  85                         int lastDir = path.LastIndexOf (DirectorySeparatorChar);
  86                         if (lastDir > 0)
  87                                 return path.Substring (0, lastDir);
  88                         return "";
  89                 }
  90
  91                 public static string GetFileName (string path)
  92                 {
  93                         if (path == null || path.Length == 0)
  94                                 return path;
  95
  96                         int lastDir = path.LastIndexOf (DirectorySeparatorChar);
  97                         if (lastDir >= 0)
  98                                 return path.Substring (lastDir+1);
  99
 100                         return path;
 101                 }
 102
 103                 public static string GetFullPath (string path)
 104                 {
 105                         path = _GetFullPath (path);
 106                         return GetCanonicalPath (path);
 107                 }
 108
 109                 private static string _GetFullPath (string path)
 110                 {
 111                         if (path == null)
 112                                 throw new ArgumentNullException ("path");
 113                         if (!IsPathRooted (path))
 114                                 path = UnixDirectory.GetCurrentDirectory() + DirectorySeparatorChar + path;
 115
 116                         return path;
 117                 }
 118
 119                 public static string GetCanonicalPath (string path)
 120                 {
 121                         string [] dirs;
 122                         int lastIndex;
 123                         GetPathComponents (path, out dirs, out lastIndex);
 124                         string end = string.Join ("/", dirs, 0, lastIndex);
 125                         return IsPathRooted (path) ? "/" + end : end;
 126                 }
 127
 128                 private static void GetPathComponents (string path,
 129                         out string[] components, out int lastIndex)
 130                 {
 131                         string [] dirs = path.Split (DirectorySeparatorChar);
 132                         int target = 0;
 133                         for (int i = 0; i < dirs.Length; ++i) {
 134                                 if (dirs [i] == "." || dirs [i] == string.Empty) continue;
 135                                 else if (dirs [i] == "..") {
 136                                         if (target != 0) --target;
 137                                         else ++target;
 138                                 }
 139                                 else
 140                                         dirs [target++] = dirs [i];
 141                         }
 142                         components = dirs;
 143                         lastIndex = target;
 144                 }
 145
 146                 public static string GetPathRoot (string path)
 147                 {
 148                         if (path == null)
 149                                 return null;
 150                         if (!IsPathRooted (path))
 151                                 return "";
 152                         return "/";
 153                 }
 154
 155                 public static string GetCompleteRealPath (string path)
 156                 {
 157                         if (path == null)
 158                                 throw new ArgumentNullException ("path");
 159                         string [] dirs;
 160                         int lastIndex;
 161                         GetPathComponents (path, out dirs, out lastIndex);
 162                         StringBuilder realPath = new StringBuilder ();
 163                         if (dirs.Length > 0) {
 164                                 string dir = IsPathRooted (path) ? "/" : "";
 165                                 dir += dirs [0];
 166                                 realPath.Append (GetRealPath (dir));
 167                         }
 168                         for (int i = 1; i < lastIndex; ++i) {
 169                                 realPath.Append ("/").Append (dirs [i]);
 170                                 string p = GetRealPath (realPath.ToString());
 171                                 realPath.Remove (0, realPath.Length);
 172                                 realPath.Append (p);
 173                         }
 174                         return realPath.ToString ();
 175                 }
 176
 177                 public static string GetRealPath (string path)
 178                 {
 179                         do {
 180                                 string name = ReadSymbolicLink (path);
 181                                 if (name == null)
 182                                         return path;
 183                                 if (IsPathRooted (name))
 184                                         path = name;
 185                                 else {
 186                                         path = GetDirectoryName (path) + DirectorySeparatorChar + name;
 187                                         path = GetCanonicalPath (path);
 188                                 }
 189                         } while (true);
 190                 }
 191
 192                 // Read the specified symbolic link.  If the file isn't a symbolic link,
 193                 // return null; otherwise, return the contents of the symbolic link.
 194                 //
 195                 // readlink(2) is horribly evil, as there is no way to query how big the
 196                 // symlink contents are.  Consequently, it's trial and error...
 197                 internal static string ReadSymbolicLink (string path)
 198                 {
 199                         StringBuilder buf = new StringBuilder (256);
 200                         do {
 201                                 int r = Syscall.readlink (path, buf);
 202                                 if (r < 0) {
 203                                         Error e;
 204                                         switch (e = Syscall.GetLastError()) {
 205                                         case Error.EINVAL:
 206                                                 // path isn't a symbolic link
 207                                                 return null;
 208                                         default:
 209                                                 UnixMarshal.ThrowExceptionForError (e);
 210                                                 break;
 211                                         }
 212                                 }
 213                                 else if (r == buf.Capacity) {
 214                                         buf.Capacity *= 2;
 215                                 }
 216                                 else
 217                                         return buf.ToString (0, r);
 218                         } while (true);
 219                 }
 220
 221                 public static bool IsPathRooted (string path)
 222                 {
 223                         if (path == null || path.Length == 0)
 224                                 return false;
 225                         return path [0] == DirectorySeparatorChar;
 226                 }
 227
 228                 internal static void CheckPath (string path)
 229                 {
 230                         if (path == null)
 231                                 throw new ArgumentNullException ();
 232                         if (path.IndexOfAny (UnixPath.InvalidPathChars) != -1)
 233                                 throw new ArgumentException ("Invalid characters in path.");
 234                 }
 235         }
 236 }
 237
 238 // vim: noexpandtab