/*
* Copyright 2000-2009 JetBrains s.r.o.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* @author max
*/
package com.intellij.util.io;
import com.intellij.openapi.diagnostic.Logger;
import sun.misc.Cleaner;
import sun.nio.ch.DirectBuffer;
import java.io.File;
import java.io.IOException;
import java.nio.MappedByteBuffer;
import java.security.AccessController;
import java.security.PrivilegedAction;
public abstract class MappedBufferWrapper {
protected static final Logger LOG = Logger.getInstance("#com.intellij.util.io.MappedBufferWrapper");
protected final File myFile;
protected final long myPosition;
protected final long myLength;
private volatile MappedByteBuffer myBuffer;
public MappedBufferWrapper(final File file, final long pos, final long length) {
myFile = file;
myPosition = pos;
myLength = length;
}
protected abstract MappedByteBuffer map() throws IOException;
private static final int MAX_FORCE_ATTEMPTS = 10;
public final void unmap() {
long started = IOStatistics.DEBUG ? System.currentTimeMillis() : 0;
MappedByteBuffer buffer = getIfCached();
myBuffer = null;
if (!unmapMappedByteBuffer142b19(buffer)) {
LOG.error("Unmapping failed for: " + myFile);
}
if (IOStatistics.DEBUG) {
long finished = System.currentTimeMillis();
if (finished - started > IOStatistics.MIN_IO_TIME_TO_REPORT) {
IOStatistics.dump("Unmapped " + myFile + "," + myPosition + "," + myLength + " for " + (finished - started));
}
}
}
public MappedByteBuffer getIfCached() {
return myBuffer;
}
public MappedByteBuffer buf() throws IOException {
MappedByteBuffer buffer = myBuffer;
if (buffer == null) {
myBuffer = buffer = map();
}
return buffer;
}
private static boolean unmapMappedByteBuffer142b19(MappedByteBuffer buffer) {
return clean(buffer);
}
private static boolean clean(final MappedByteBuffer buffer) {
if (buffer == null) return true;
if (!tryForce(buffer)) {
return false;
}
return AccessController.doPrivileged(new PrivilegedAction<Object>() {
public Object run() {
try {
Cleaner cleaner = ((DirectBuffer)buffer).cleaner();
if (cleaner != null) cleaner.clean(); // Already cleaned otherwise
return null;
}
catch (Exception e) {
return buffer;
}
}
}) == null;
}
private static boolean tryForce(MappedByteBuffer buffer) {
for (int i = 0; i < MAX_FORCE_ATTEMPTS; i++) {
try {
buffer.force();
return true;
}
catch (Throwable e) {
LOG.info(e);
try {
Thread.sleep(10);
}
catch (InterruptedException e1) {
// Can't be
}
}
}
return false;
}
public boolean isMapped() {
return getIfCached() != null;
}
public void flush() {
final MappedByteBuffer buffer = getIfCached();
if (buffer != null) {
tryForce(buffer);
}
}
public void dispose() {
unmap();
}
}