1 /*
2 * Copyright (c) 2000, 2018, 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 sun.nio.ch;
27
28 import java.io.FileDescriptor;
29 import java.io.IOException;
30 import java.security.PrivilegedAction;
31 import sun.misc.SharedSecrets;
32 import sun.misc.JavaIOFileDescriptorAccess;
33
34 class FileDispatcherImpl extends FileDispatcher {
35
36 // set to true if fast file transmission (TransmitFile) is enabled
37 private static final boolean fastFileTransfer;
38
39 /**
40 * Indicates if the dispatcher should first advance the file position
41 * to the end of file when writing.
42 */
43 private final boolean append;
44
45 FileDispatcherImpl(boolean append) {
46 this.append = append;
47 }
48
49 FileDispatcherImpl() {
50 this(false);
51 }
52
53 @Override
54 boolean needsPositionLock() {
55 return true;
56 }
57
58 int read(FileDescriptor fd, long address, int len)
59 throws IOException
60 {
61 return read0(fd, address, len);
62 }
63
64 int pread(FileDescriptor fd, long address, int len, long position)
65 throws IOException
66 {
67 return pread0(fd, address, len, position);
68 }
69
70 long readv(FileDescriptor fd, long address, int len) throws IOException {
71 return readv0(fd, address, len);
72 }
73
74 int write(FileDescriptor fd, long address, int len) throws IOException {
75 return write0(fd, address, len, append);
76 }
77
78 int pwrite(FileDescriptor fd, long address, int len, long position)
79 throws IOException
80 {
81 return pwrite0(fd, address, len, position);
82 }
83
84 long writev(FileDescriptor fd, long address, int len) throws IOException {
85 return writev0(fd, address, len, append);
86 }
87
88 int force(FileDescriptor fd, boolean metaData) throws IOException {
89 return force0(fd, metaData);
90 }
91
92 int truncate(FileDescriptor fd, long size) throws IOException {
93 return truncate0(fd, size);
94 }
95
96 int allocate(FileDescriptor fd, long size) throws IOException {
97 // truncate0() works for extending and truncating file size
98 return truncate0(fd, size);
99 }
100
101 long size(FileDescriptor fd) throws IOException {
102 return size0(fd);
103 }
104
105 int lock(FileDescriptor fd, boolean blocking, long pos, long size,
106 boolean shared) throws IOException
107 {
108 return lock0(fd, blocking, pos, size, shared);
109 }
110
111 void release(FileDescriptor fd, long pos, long size) throws IOException {
112 release0(fd, pos, size);
113 }
114
115 void close(FileDescriptor fd) throws IOException {
116 close0(fd);
117 }
118
119 FileDescriptor duplicateForMapping(FileDescriptor fd) throws IOException {
120 // on Windows we need to keep a handle to the file
121 JavaIOFileDescriptorAccess fdAccess =
122 SharedSecrets.getJavaIOFileDescriptorAccess();
123 FileDescriptor result = new FileDescriptor();
124 long handle = duplicateHandle(fdAccess.getHandle(fd));
125 fdAccess.setHandle(result, handle);
126 return result;
127 }
128
129 boolean canTransferToDirectly(java.nio.channels.SelectableChannel sc) {
130 return fastFileTransfer && sc.isBlocking();
131 }
132
133 boolean transferToDirectlyNeedsPositionLock() {
134 return true;
135 }
136
137 static boolean isFastFileTransferRequested() {
138 String fileTransferProp = java.security.AccessController.doPrivileged(
139 new PrivilegedAction<String>() {
140 @Override
141 public String run() {
142 return System.getProperty("jdk.nio.enableFastFileTransfer");
143 }
144 });
145 boolean enable;
146 if ("".equals(fileTransferProp)) {
147 enable = true;
148 } else {
149 enable = Boolean.parseBoolean(fileTransferProp);
150 }
151 return enable;
152 }
153
154 static {
155 IOUtil.load();
156 fastFileTransfer = isFastFileTransferRequested();
157 }
158
159 //-- Native methods
160
161 static native int read0(FileDescriptor fd, long address, int len)
162 throws IOException;
163
164 static native int pread0(FileDescriptor fd, long address, int len,
165 long position) throws IOException;
166
167 static native long readv0(FileDescriptor fd, long address, int len)
168 throws IOException;
169
170 static native int write0(FileDescriptor fd, long address, int len, boolean append)
171 throws IOException;
172
173 static native int pwrite0(FileDescriptor fd, long address, int len,
174 long position) throws IOException;
175
176 static native long writev0(FileDescriptor fd, long address, int len, boolean append)
177 throws IOException;
178
179 static native int force0(FileDescriptor fd, boolean metaData)
180 throws IOException;
181
182 static native int truncate0(FileDescriptor fd, long size)
183 throws IOException;
184
185 static native long size0(FileDescriptor fd) throws IOException;
186
187 static native int lock0(FileDescriptor fd, boolean blocking, long pos,
188 long size, boolean shared) throws IOException;
189
190 static native void release0(FileDescriptor fd, long pos, long size)
191 throws IOException;
192
193 static native void close0(FileDescriptor fd) throws IOException;
194
195 static native void closeByHandle(long fd) throws IOException;
196
197 static native long duplicateHandle(long fd) throws IOException;
198 }