FileDescriptor.java: Implement on top of FileChannel.

* java/io/FileDescriptor.java:  Implement on top of FileChannel.
	Remove native methods.

	* java/io/natFileDescriptorEcos.cc:  Remove file.
	* java/io/natFileDescriptorPosix.cc:  Remove file.
	* java/io/natFileDescriptorWin32.cc:  Remove file.
	* java/io/FileInputStream.java (ch):  Change type to FileChannelImpl.
	(<init>(File)):  Allocate a FileChannelImpl, not a FileDescriptor.
	(<init>(FileChannelImpl)):  New package-private constructor.
	(<init>(FileDescriptor)):  Extract FileChannelImpl from arg.
	(available, close, read, skip):  Implement using FileChannelImpl.
	(getFD):  Allocate FileDescriptor if needed.
	(getChannel):  Is now trivial.
	* java/io/FileOutputStream.java:  Corresponding changes.
	* java/io/RandomAccessFile.java:  Corresponding changes.

From-SVN: r78661

libjava/java/io/FileInputStream.java

@@ -1,5 +1,5 @@
 /* FileInputStream.java -- An input stream that reads from disk files.
-   Copyright (C) 1998, 2002, 2003 Free Software Foundation, Inc.
+   Copyright (C) 1998, 2002, 2003, 2004 Free Software Foundation, Inc.
 
 This file is part of GNU Classpath.
 
@@ -39,7 +39,7 @@ exception statement from your version. */
 package java.io;
 
 import java.nio.channels.FileChannel;
-import java.nio.channels.FileChannelImpl;
+import gnu.java.nio.channels.FileChannelImpl;
 
 /* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
  * "The Java Language Specification", ISBN 0-201-63451-1
@@ -60,7 +60,7 @@ public class FileInputStream extends InputStream
    */
   private FileDescriptor fd;
 
-  private FileChannel ch;  /* cached associated file-channel */
+  private FileChannelImpl ch;
 
   /**
    * This method initializes a <code>FileInputStream</code> to read from the
@@ -107,7 +107,7 @@ public class FileInputStream extends InputStream
     if (file.isDirectory())
       throw new FileNotFoundException(file.getPath() + " is a directory");
 
-    fd = new FileDescriptor(file.getPath(), FileDescriptor.READ);
+    ch = new FileChannelImpl (file.getPath(), FileChannelImpl.READ);
   }
 
   /**
@@ -133,6 +133,12 @@ public class FileInputStream extends InputStream
       s.checkRead(fdObj);
 
     fd = fdObj;
+    ch = (FileChannelImpl) fdObj.channel;
+  }
+
+  FileInputStream(FileChannelImpl ch)
+  {
+    this.ch = ch;
   }
 
   /**
@@ -156,7 +162,7 @@ public class FileInputStream extends InputStream
    */
   public int available() throws IOException
   {
-    return fd.available();
+    return ch.available();
   }
 
   /**
@@ -168,8 +174,7 @@ public class FileInputStream extends InputStream
    */
   public void close() throws IOException
   {
-    if (fd.valid())
-      fd.close();
+    ch.close();
   }
 
   protected void finalize() throws IOException
@@ -189,9 +194,12 @@ public class FileInputStream extends InputStream
    */
   public final FileDescriptor getFD() throws IOException
   {
-    if (!fd.valid())
-      throw new IOException();
-    return fd;
+    synchronized (this)
+      {
+	if (fd == null)
+	  fd = new FileDescriptor (ch);
+	return fd;
+      }
   }
 
   /**
@@ -207,7 +215,7 @@ public class FileInputStream extends InputStream
    */
   public int read() throws IOException
   {
-    return fd.read();
+    return ch.read();
   }
 
   /**
@@ -258,7 +266,7 @@ public class FileInputStream extends InputStream
         || offset + len > buf.length)
       throw new ArrayIndexOutOfBoundsException();
 
-    return fd.read(buf, offset, len);
+    return ch.read(buf, offset, len);
   }
 
   /**
@@ -281,9 +289,9 @@ public class FileInputStream extends InputStream
     if (numBytes == 0)
       return 0;
 
-    long curPos = fd.getFilePointer ();
-    long newPos = fd.seek (numBytes, FileDescriptor.CUR, true);
-    return newPos - curPos;
+    long oldPos = ch.position ();
+    ch.position(oldPos + numBytes);
+    return ch.position() - oldPos;
   }
 
   /**
@@ -294,9 +302,6 @@ public class FileInputStream extends InputStream
    */
   public synchronized FileChannel getChannel () 
   {
-    if (ch == null)
-      ch = new FileChannelImpl (fd, false, this);
-    
     return ch;
   }