com.itextpdf.io.source.BufferCleaner Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.
*
* NOTE: that this code was edited since original code is compatible with android sdk not lower than 26.
* This edited code has been verified to be compatible with android sdk 19.
*/
package com.itextpdf.io.source;
import java.io.IOException;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.nio.ByteBuffer;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Objects;
class BufferCleaner {
Class unmappableBufferClass;
final Method method;
final Object theUnsafe;
BufferCleaner(final Class unmappableBufferClass, final Method method, final Object theUnsafe) {
this.unmappableBufferClass = unmappableBufferClass;
this.method = method;
this.theUnsafe = theUnsafe;
}
void freeBuffer(String resourceDescription, final java.nio.ByteBuffer buffer) throws IOException {
assert Objects.equals(void.class, method.getReturnType());
assert method.getParameterTypes().length == 1;
assert Objects.equals(ByteBuffer.class, method.getParameterTypes()[0]);
if (!buffer.isDirect()) {
throw new IllegalArgumentException("unmapping only works with direct buffers");
}
if (!unmappableBufferClass.isInstance(buffer)) {
throw new IllegalArgumentException("buffer is not an instance of " + unmappableBufferClass.getName());
}
final Throwable error = AccessController.doPrivileged(new PrivilegedAction() {
public Throwable run() {
try {
method.invoke(theUnsafe, buffer);
return null;
} catch (IllegalAccessException | InvocationTargetException e) {
return e;
}
}
});
if (error != null) {
throw new IOException("Unable to unmap the mapped buffer: " + resourceDescription, error);
}
}
static Object unmapHackImpl() {
try {
// *** sun.misc.Unsafe unmapping (Java 9+) ***
final Class unsafeClass = Class.forName("sun.misc.Unsafe");
final Method method = unsafeClass.getDeclaredMethod("invokeCleaner", ByteBuffer.class);
final Field f = unsafeClass.getDeclaredField("theUnsafe");
f.setAccessible(true);
final Object theUnsafe = f.get(null);
return new BufferCleaner(ByteBuffer.class, method, theUnsafe);
} catch (Exception e) {
return e.getMessage();
}
}
}