1 /*

     2  * Copyright (c) 1998, 2016, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 package java.io;

    27 

    28 import java.lang.annotation.Native;

    29 

    30 /**

    31  * Package-private abstract class for the local filesystem abstraction.

    32  */

    33 

    34 abstract class FileSystem {

    35 

    36     /* -- Normalization and construction -- */

    37 

    38     /**

    39      * Return the local filesystem's name-separator character.

    40      */

    41     public abstract char getSeparator();

    42 

    43     /**

    44      * Return the local filesystem's path-separator character.

    45      */

    46     public abstract char getPathSeparator();

    47 

    48     /**

    49      * Convert the given pathname string to normal form.  If the string is

    50      * already in normal form then it is simply returned.

    51      */

    52     public abstract String normalize(String path);

    53 

    54     /**

    55      * Compute the length of this pathname string's prefix.  The pathname

    56      * string must be in normal form.

    57      */

    58     public abstract int prefixLength(String path);

    59 

    60     /**

    61      * Resolve the child pathname string against the parent.

    62      * Both strings must be in normal form, and the result

    63      * will be in normal form.

    64      */

    65     public abstract String resolve(String parent, String child);

    66 

    67     /**

    68      * Return the parent pathname string to be used when the parent-directory

    69      * argument in one of the two-argument File constructors is the empty

    70      * pathname.

    71      */

    72     public abstract String getDefaultParent();

    73 

    74     /**

    75      * Post-process the given URI path string if necessary.  This is used on

    76      * win32, e.g., to transform "/c:/foo" into "c:/foo".  The path string

    77      * still has slash separators; code in the File class will translate them

    78      * after this method returns.

    79      */

    80     public abstract String fromURIPath(String path);

    81 

    82 

    83     /* -- Path operations -- */

    84 

    85     /**

    86      * Tell whether or not the given abstract pathname is absolute.

    87      */

    88     public abstract boolean isAbsolute(File f);

    89 

    90     /**

    91      * Resolve the given abstract pathname into absolute form.  Invoked by the

    92      * getAbsolutePath and getCanonicalPath methods in the File class.

    93      */

    94     public abstract String resolve(File f);

    95 

    96     public abstract String canonicalize(String path) throws IOException;

    97 

    98 

    99     /* -- Attribute accessors -- */

   100 

   101     /* Constants for simple boolean attributes */

   102     @Native public static final int BA_EXISTS    = 0x01;

   103     @Native public static final int BA_REGULAR   = 0x02;

   104     @Native public static final int BA_DIRECTORY = 0x04;

   105     @Native public static final int BA_HIDDEN    = 0x08;

   106 

   107     /**

   108      * Return the simple boolean attributes for the file or directory denoted

   109      * by the given abstract pathname, or zero if it does not exist or some

   110      * other I/O error occurs.

   111      */

   112     public abstract int getBooleanAttributes(File f);

   113 

   114     @Native public static final int ACCESS_READ    = 0x04;

   115     @Native public static final int ACCESS_WRITE   = 0x02;

   116     @Native public static final int ACCESS_EXECUTE = 0x01;

   117 

   118     /**

   119      * Check whether the file or directory denoted by the given abstract

   120      * pathname may be accessed by this process.  The second argument specifies

   121      * which access, ACCESS_READ, ACCESS_WRITE or ACCESS_EXECUTE, to check.

   122      * Return false if access is denied or an I/O error occurs

   123      */

   124     public abstract boolean checkAccess(File f, int access);

   125     /**

   126      * Set on or off the access permission (to owner only or to all) to the file

   127      * or directory denoted by the given abstract pathname, based on the parameters

   128      * enable, access and oweronly.

   129      */

   130     public abstract boolean setPermission(File f, int access, boolean enable, boolean owneronly);

   131 

   132     /**

   133      * Return the time at which the file or directory denoted by the given

   134      * abstract pathname was last modified, or zero if it does not exist or

   135      * some other I/O error occurs.

   136      */

   137     public abstract long getLastModifiedTime(File f);

   138 

   139     /**

   140      * Return the length in bytes of the file denoted by the given abstract

   141      * pathname, or zero if it does not exist, is a directory, or some other

   142      * I/O error occurs.

   143      */

   144     public abstract long getLength(File f);

   145 

   146 

   147     /* -- File operations -- */

   148 

   149     /**

   150      * Create a new empty file with the given pathname.  Return

   151      * <code>true</code> if the file was created and <code>false</code> if a

   152      * file or directory with the given pathname already exists.  Throw an

   153      * IOException if an I/O error occurs.

   154      */

   155     public abstract boolean createFileExclusively(String pathname)

   156         throws IOException;

   157 

   158     /**

   159      * Delete the file or directory denoted by the given abstract pathname,

   160      * returning <code>true</code> if and only if the operation succeeds.

   161      */

   162     public abstract boolean delete(File f);

   163 

   164     /**

   165      * List the elements of the directory denoted by the given abstract

   166      * pathname.  Return an array of strings naming the elements of the

   167      * directory if successful; otherwise, return <code>null</code>.

   168      */

   169     public abstract String[] list(File f);

   170 

   171     /**

   172      * Create a new directory denoted by the given abstract pathname,

   173      * returning <code>true</code> if and only if the operation succeeds.

   174      */

   175     public abstract boolean createDirectory(File f);

   176 

   177     /**

   178      * Rename the file or directory denoted by the first abstract pathname to

   179      * the second abstract pathname, returning <code>true</code> if and only if

   180      * the operation succeeds.

   181      */

   182     public abstract boolean rename(File f1, File f2);

   183 

   184     /**

   185      * Set the last-modified time of the file or directory denoted by the

   186      * given abstract pathname, returning <code>true</code> if and only if the

   187      * operation succeeds.

   188      */

   189     public abstract boolean setLastModifiedTime(File f, long time);

   190 

   191     /**

   192      * Mark the file or directory denoted by the given abstract pathname as

   193      * read-only, returning <code>true</code> if and only if the operation

   194      * succeeds.

   195      */

   196     public abstract boolean setReadOnly(File f);

   197 

   198 

   199     /* -- Filesystem interface -- */

   200 

   201     /**

   202      * List the available filesystem roots.

   203      */

   204     public abstract File[] listRoots();

   205 

   206     /* -- Disk usage -- */

   207     @Native public static final int SPACE_TOTAL  = 0;

   208     @Native public static final int SPACE_FREE   = 1;

   209     @Native public static final int SPACE_USABLE = 2;

   210 

   211     public abstract long getSpace(File f, int t);

   212 

   213     /* -- Basic infrastructure -- */

   214 

   215     /**

   216      * Retrieve the maximum length of a component of a file path.

   217      *

   218      * @return The maximum length of a file path component.

   219      */

   220     public abstract int getNameMax(String path);

   221 

   222     /**

   223      * Compare two abstract pathnames lexicographically.

   224      */

   225     public abstract int compare(File f1, File f2);

   226 

   227     /**

   228      * Compute the hash code of an abstract pathname.

   229      */

   230     public abstract int hashCode(File f);

   231 

   232     // Flags for enabling/disabling performance optimizations for file

   233     // name canonicalization

   234     static boolean useCanonCaches      = true;

   235     static boolean useCanonPrefixCache = true;

   236 

   237     private static boolean getBooleanProperty(String prop, boolean defaultVal) {

   238         return Boolean.parseBoolean(System.getProperty(prop,

   239                 String.valueOf(defaultVal)));

   240     }

   241 

   242     static {

   243         useCanonCaches      = getBooleanProperty("sun.io.useCanonCaches",

   244                                                  useCanonCaches);

   245         useCanonPrefixCache = getBooleanProperty("sun.io.useCanonPrefixCache",

   246                                                  useCanonPrefixCache);

   247     }

   248 }