org.eclipse.tracecompass.ctf.core/src/org/eclipse/linuxtools/internal/ctf/core/SafeMappedByteBuffer.java

   1 /*******************************************************************************
   2  * Copyright (c) 2014 Ericsson
   3  *
   4  * All rights reserved. This program and the accompanying materials are made
   5  * available under the terms of the Eclipse Public License v1.0 which
   6  * accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  * Contributors:
  10  *     Marc-Andre Laperle - Initial API and implementation
  11  *******************************************************************************/
  12
  13 package org.eclipse.linuxtools.internal.ctf.core;
  14
  15 import java.io.IOException;
  16 import java.nio.ByteBuffer;
  17 import java.nio.channels.FileChannel;
  18
  19 /**
  20  * A common utility for mapping a ByteBuffer safely to work around a bug on
  21  * Windows which prevents deleting a file after it was mapped. On Windows, the
  22  * ByteBuffer will be allocated and the file will be read instead of being
  23  * mapped.
  24  *
  25  * http://bugs.java.com/view_bug.do?bug_id=4715154
  26  */
  27 public class SafeMappedByteBuffer {
  28
  29     private static final boolean IS_WIN32 = System.getProperty("os.name").startsWith("Windows");  //$NON-NLS-1$//$NON-NLS-2$
  30
  31     /**
  32      * Maps a region of this channel's file directly into memory. On Windows,
  33      * this will allocate a new ByteBuffer and read the file.
  34      *
  35      * @param fc
  36      *            the file channel
  37      * @param mode
  38      *            the mapping mode
  39      * @param position
  40      *            the position within the file
  41      * @param size
  42      *            the size of the region to be mapped (or read)
  43      * @return the mapped ByteBuffer
  44      * @throws IOException
  45      *             on FileChannel operations failures
  46      */
  47     public static ByteBuffer map(FileChannel fc, FileChannel.MapMode mode, long position, long size) throws IOException {
  48         ByteBuffer byteBuffer;
  49         if (IS_WIN32) {
  50             byteBuffer = ByteBuffer.allocate((int) size);
  51             fc.read(byteBuffer, position);
  52         } else {
  53             byteBuffer = fc.map(mode, position, size);
  54         }
  55
  56         return byteBuffer;
  57     }
  58 }