java/src/main/com/google/appengine/tools/admin/Utility.java

   1 // Copyright 2008 Google Inc. All Rights Reserved.
   2
   3 package com.google.appengine.tools.admin;
   4
   5 import java.io.File;
   6
   7 /**
   8  * Utility methods for this package.
   9  *
  10  */
  11 public class Utility {
  12
  13   private static final String FORWARD_SLASH = "/";
  14
  15   /**
  16    * Attempts to find a symlink executable, since Java doesn't natively
  17    * support them but we don't like excessive copying.
  18    *
  19    * @return either {@code null} if no links can be made, or an executable
  20    *   program that we believe will make symlinks.
  21    */
  22   public static File findLink() {
  23     File ln = null;
  24     if (isOsUnix()) {
  25       ln = new File("/bin/ln");
  26       if (!ln.exists()) {
  27         ln = new File("/usr/bin/ln");
  28         if (!ln.exists()) {
  29           ln = null;
  30         }
  31       }
  32     }
  33     return ln;
  34   }
  35
  36   /**
  37    * Test for Unix (to include MacOS), vice Windows.
  38    */
  39   public static boolean isOsUnix() {
  40     return File.separator.equals(FORWARD_SLASH);
  41   }
  42
  43   /**
  44    * Test for Windows, vice Unix (to include MacOS).
  45    */
  46   public static boolean isOsWindows() {
  47     return !isOsUnix();
  48   }
  49
  50   public static String calculatePath(File f, File base) {
  51     int offset = base.getPath().length();
  52     String path = f.getPath().substring(offset);
  53     if (File.separatorChar == '\\') {
  54       path = path.replace('\\', '/');
  55     }
  56
  57     for (offset = 0; path.charAt(offset) == '/'; ++offset) {
  58     }
  59     if (offset > 0) {
  60       path = path.substring(offset);
  61     }
  62
  63     return path;
  64   }
  65
  66   /**
  67    * Escapes the string as a JSON value.
  68    *
  69    * @param s raw string that we want to set as JSON value.
  70    * @return unquoted JSON escaped string
  71    */
  72   public static String jsonEscape(String s) {
  73     StringBuilder stringBuilder = new StringBuilder();
  74     for (int i = 0; i < s.length(); i++) {
  75       char ch = s.charAt(i);
  76
  77       switch (ch) {
  78         case '"':
  79           stringBuilder.append("\\\"");
  80           break;
  81
  82         case '\\':
  83           stringBuilder.append("\\\\");
  84           break;
  85
  86         case '\b':
  87           stringBuilder.append("\\b");
  88           break;
  89
  90         case '\f':
  91           stringBuilder.append("\\f");
  92           break;
  93
  94         case '\n':
  95           stringBuilder.append("\\n");
  96           break;
  97
  98         case '\r':
  99           stringBuilder.append("\\r");
 100           break;
 101
 102         case '\t':
 103           stringBuilder.append("\\t");
 104           break;
 105
 106         case '/':
 107           stringBuilder.append("\\/");
 108           break;
 109
 110         default:
 111           if ((ch >= 0x20) && (ch < 0x7f)) {
 112             stringBuilder.append(ch);
 113           } else {
 114             stringBuilder.append(String.format("\\u%04x", (int) ch));
 115           }
 116           break;
 117       }
 118     }
 119
 120     return stringBuilder.toString();
 121   }
 122
 123   private Utility() {
 124   }
 125 }