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 import java.util.ArrayList; 28 import java.util.List; 29 30 /** 31 * Instances of the file descriptor class serve as an opaque handle 32 * to the underlying machine-specific structure representing an open 33 * file, an open socket, or another source or sink of bytes. The 34 * main practical use for a file descriptor is to create a 35 * <code>FileInputStream</code> or <code>FileOutputStream</code> to 36 * contain it. 37 * <p> 38 * Applications should not create their own file descriptors. 39 * 40 * @author Pavani Diwanji 41 * @see java.io.FileInputStream 42 * @see java.io.FileOutputStream 43 * @since JDK1.0 44 */ 45 public final class FileDescriptor { 46 47 private int fd; 48 private Closeable parent; 49 private List<Closeable> otherParents; 50 private boolean closed; 51 52 /** 53 * Constructs an (invalid) FileDescriptor 54 * object. 55 */ 56 public /**/ FileDescriptor() { 57 fd = -1; 58 } 59 60 private /* */ FileDescriptor(int fd) { 61 this.fd = fd; 62 } 63 64 /** 65 * A handle to the standard input stream. Usually, this file 66 * descriptor is not used directly, but rather via the input stream 67 * known as <code>System.in</code>. 68 * 69 * @see java.lang.System#in 70 */ 71 public static final FileDescriptor in = new FileDescriptor(0); 72 73 /** 74 * A handle to the standard output stream. Usually, this file 75 * descriptor is not used directly, but rather via the output stream 76 * known as <code>System.out</code>. 77 * @see java.lang.System#out 78 */ 79 public static final FileDescriptor out = new FileDescriptor(1); 80 81 /** 141 new sun.misc.JavaIOFileDescriptorAccess() { 142 public void set(FileDescriptor obj, int fd) { 143 obj.fd = fd; 144 } 145 146 public int get(FileDescriptor obj) { 147 return obj.fd; 148 } 149 150 public void setHandle(FileDescriptor obj, long handle) { 151 throw new UnsupportedOperationException(); 152 } 153 154 public long getHandle(FileDescriptor obj) { 155 throw new UnsupportedOperationException(); 156 } 157 } 158 ); 159 } 160 161 /* 162 * Package private methods to track referents. 163 * If multiple streams point to the same FileDescriptor, we cycle 164 * through the list of all referents and call close() 165 */ 166 167 /** 168 * Attach a Closeable to this FD for tracking. 169 * parent reference is added to otherParents when 170 * needed to make closeAll simpler. 171 */ 172 synchronized void attach(Closeable c) { 173 if (parent == null) { 174 // first caller gets to do this 175 parent = c; 176 } else if (otherParents == null) { 177 otherParents = new ArrayList<>(); 178 otherParents.add(parent); 179 otherParents.add(c); 180 } else { 181 otherParents.add(c); 182 } 183 } 184 185 /** 186 * Cycle through all Closeables sharing this FD and call 187 * close() on each one. 188 * 189 * The caller closeable gets to call close0(). 190 */ 191 @SuppressWarnings("try") 192 synchronized void closeAll(Closeable releaser) throws IOException { 193 if (!closed) { 194 closed = true; 195 IOException ioe = null; 196 try (Closeable c = releaser) { 197 if (otherParents != null) { 198 for (Closeable referent : otherParents) { 199 try { 200 referent.close(); 201 } catch(IOException x) { 202 if (ioe == null) { 203 ioe = x; 204 } else { 205 ioe.addSuppressed(x); 206 } 207 } 208 } 209 } 210 } catch(IOException ex) { 211 /* 212 * If releaser close() throws IOException 213 * add other exceptions as suppressed. 214 */ 215 if (ioe != null) 216 ex.addSuppressed(ioe); 217 ioe = ex; 218 } finally { 219 if (ioe != null) 220 throw ioe; 221 } 222 } 223 } 224 } | 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.util.concurrent.atomic.AtomicInteger; 29 30 /** 31 * Instances of the file descriptor class serve as an opaque handle 32 * to the underlying machine-specific structure representing an open 33 * file, an open socket, or another source or sink of bytes. The 34 * main practical use for a file descriptor is to create a 35 * <code>FileInputStream</code> or <code>FileOutputStream</code> to 36 * contain it. 37 * <p> 38 * Applications should not create their own file descriptors. 39 * 40 * @author Pavani Diwanji 41 * @see java.io.FileInputStream 42 * @see java.io.FileOutputStream 43 * @since JDK1.0 44 */ 45 public final class FileDescriptor { 46 47 private int fd; 48 49 /** 50 * A counter for tracking the FIS/FOS/RAF instances that 51 * use this FileDescriptor. The FIS/FOS.finalize() will not release 52 * the FileDescriptor if it is still under user by a stream. 53 */ 54 private AtomicInteger useCount; 55 56 /** 57 * Constructs an (invalid) FileDescriptor 58 * object. 59 */ 60 public /**/ FileDescriptor() { 61 fd = -1; 62 useCount = new AtomicInteger(); 63 } 64 65 private /* */ FileDescriptor(int fd) { 66 this.fd = fd; 67 useCount = new AtomicInteger(); 68 } 69 70 /** 71 * A handle to the standard input stream. Usually, this file 72 * descriptor is not used directly, but rather via the input stream 73 * known as <code>System.in</code>. 74 * 75 * @see java.lang.System#in 76 */ 77 public static final FileDescriptor in = new FileDescriptor(0); 78 79 /** 80 * A handle to the standard output stream. Usually, this file 81 * descriptor is not used directly, but rather via the output stream 82 * known as <code>System.out</code>. 83 * @see java.lang.System#out 84 */ 85 public static final FileDescriptor out = new FileDescriptor(1); 86 87 /** 147 new sun.misc.JavaIOFileDescriptorAccess() { 148 public void set(FileDescriptor obj, int fd) { 149 obj.fd = fd; 150 } 151 152 public int get(FileDescriptor obj) { 153 return obj.fd; 154 } 155 156 public void setHandle(FileDescriptor obj, long handle) { 157 throw new UnsupportedOperationException(); 158 } 159 160 public long getHandle(FileDescriptor obj) { 161 throw new UnsupportedOperationException(); 162 } 163 } 164 ); 165 } 166 167 // package private methods used by FIS, FOS and RAF 168 169 int incrementAndGetUseCount() { 170 return useCount.incrementAndGet(); 171 } 172 173 int decrementAndGetUseCount() { 174 return useCount.decrementAndGet(); 175 } 176 } |