1 /* PlatformHelper.java -- Isolate OS-specific IO helper methods and variables
2 Copyright (C) 1998, 2002 Free Software Foundation, Inc.
4 This file is part of GNU Classpath.
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14 General Public License for more details.
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18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
21 Linking this library statically or dynamically with other modules is
22 making a combined work based on this library. Thus, the terms and
23 conditions of the GNU General Public License cover the whole
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27 permission to link this library with independent modules to produce an
28 executable, regardless of the license terms of these independent
29 modules, and to copy and distribute the resulting executable under
30 terms of your choice, provided that you also meet, for each linked
31 independent module, the terms and conditions of the license of that
32 module. An independent module is a module which is not derived from
33 or based on this library. If you modify this library, you may extend
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35 obligated to do so. If you do not wish to do so, delete this
36 exception statement from your version. */
40 import java.util.StringTokenizer;
43 * We had many changes in File.java, URLStreamHandler.java etc. to handle
44 * path representations on different platforms (Windows/Unix-family).
45 * Finally we'd like to collect all these ad hoc codes into this utility class.
48 public class PlatformHelper
50 public static final boolean isWindows = System.getProperty("os.name").indexOf("Windows") >= 0;
51 public static final String separator = System.getProperty("file.separator");
52 public static final char separatorChar = separator.charAt(0);
53 public static final String pathSeparator = System.getProperty("path.separator");
54 public static final char pathSeparatorChar = pathSeparator.charAt(0);
57 * On most platforms 260 is equal or greater than a max path value,
58 * so we can set the initial buffer size of StringBuffer to half of this value
59 * to improve performance.
61 public static final int INITIAL_MAX_PATH = 260/2;
64 * This routine checks the input param "path" whether it begins with root path
67 * if yes, return the len of root path prefix;
68 * --for Unix-family platform, root path begins with "/" and len is 1
69 * --for Windows platform, root path begins with "drive:\\" and len is 3
71 public static final int beginWithRootPathPrefix(String path)
73 if (path.startsWith("/") || path.startsWith("\\"))
80 && Character.isLetter(path.charAt(0))
81 && path.charAt(1) == ':'
82 && (path.charAt(2) == '/' || path.charAt(2) == '\\'))
89 * This routine checks the input param "path" whether it's root directory.
90 * --for Unix-family platform, root directory is "/"
91 * --for Windows platform, root directory is "\\" or "drive:\\".
93 public static final boolean isRootDirectory(String path)
95 int len = path.length();
96 return len > 0 && beginWithRootPathPrefix(path) == len;
100 * This routine canonicalizes input param "path" to formal path representation
101 * for current platform, including interpreting ".." and "." .
103 public static final String toCanonicalForm(String path)
106 if(path.indexOf('.') < 0 && path.indexOf("..") < 0)
109 String tmppath = path.replace('/', separatorChar);
110 StringBuffer canonpath;
112 // We found it'll be more efficient and easy to handle to
113 // return a lowercased canonical path
115 tmppath = tmppath.toLowerCase();
119 if ((i = beginWithRootPathPrefix(tmppath)) == 0 )
123 "canonpath = new StringBuffer(tmppath.substring(0, i))"
124 isn't very efficient because StringBuffer's
125 ensureCapacity_unsynchronized will fail definitely each time
126 and will enlarge buffer and copy contents. .
128 canonpath = new StringBuffer(INITIAL_MAX_PATH);
129 canonpath.append(tmppath.substring(0, i));
130 tmppath = tmppath.substring(i);
131 // pathdepth==0 indicates there're only root path in the buffer
134 StringTokenizer st = new StringTokenizer(tmppath, separator);
136 // Traverse each element of the path, handling "." and ".."
137 // Should handle "~" too?
138 if (st.hasMoreTokens())
141 String s = st.nextToken();
143 // Handle "." or an empty element.
144 if (s.equals(".") || s.equals(""))
147 // Handle ".." by deleting the last element from the path
153 // Strip of trailing separator
154 canonpath.setLength(canonpath.length() - 1/*separator.length()*/);
155 String tmpstr = canonpath.toString();
156 int idx = tmpstr.lastIndexOf(separator);
158 if ((idx == -1) || ((idx + 1/*separator.length()*/) > tmpstr.length()))
159 //throw new IOException("Can't happen error");
160 return path; // Shouldn't happen
162 canonpath.setLength(idx + 1/*separator.length()*/);
168 pathdepth++; //now it's more than root path
170 if (st.hasMoreTokens())
171 canonpath.append(separator);
173 while (st.hasMoreTokens());
175 if (endWithSeparator(path))
176 canonpath.append(separator);
178 String tmpstr = canonpath.toString();
179 //if (pathdepth > 0 && endWithSeparator(tmpstr) )
180 // tmpstr = tmpstr.substring(0, tmpstr.length() - 1/*separator.length()*/);
186 * This routine canonicalizes input param "path" to formal path representation
187 * for current platform, and normalize all separators to "sepchar".
189 public static final String toCanonicalForm(String path, char sepchar)
191 String tmpstr = toCanonicalForm(path);
192 tmpstr = tmpstr.replace(separatorChar, sepchar);
197 * This routine checks whether input param "path" ends with separator
199 public static final boolean endWithSeparator(String path)
201 if (path.endsWith("\\") || path.endsWith("/"))
208 * This routine removes from input param "path" the tail separator if it exists,
209 * and return the remain part.
211 public static final String removeTailSeparator(String path)
213 if (endWithSeparator(path) && !isRootDirectory(path))
214 return path.substring(0, path.length() - 1);
220 * This routine returns last index of separator in input param "path",
223 public static final int lastIndexOfSeparator(String path)
225 return Math.max(path.lastIndexOf("/"), path.lastIndexOf("\\"));