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7082299: AtomicReferenceArray should ensure that array is Object[]

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Reviewed-by: chegar, dholmes, alanb
This commit is contained in:
Doug Lea 2011-10-12 16:33:48 +01:00
parent 3c41c66fb1
commit e088fb2b1a
1 changed files with 35 additions and 8 deletions
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43
jdk/src/share/classes/java/util/concurrent/atomic/AtomicReferenceArray.java
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@ -34,8 +34,10 @@
*/
package java.util.concurrent.atomic;
import java.lang.reflect.Array;
import java.util.Arrays;
import sun.misc.Unsafe;
import java.util.*;
/**
* An array of object references in which elements may be updated
@ -49,13 +51,23 @@ import java.util.*;
public class AtomicReferenceArray<E> implements java.io.Serializable {
private static final long serialVersionUID = -6209656149925076980L;
private static final Unsafe unsafe = Unsafe.getUnsafe();
private static final int base = unsafe.arrayBaseOffset(Object[].class);
private static final Unsafe unsafe;
private static final int base;
private static final int shift;
private final Object[] array;
private static final long arrayFieldOffset;
private final Object[] array; // must have exact type Object[]
static {
int scale = unsafe.arrayIndexScale(Object[].class);
int scale;
try {
unsafe = Unsafe.getUnsafe();
arrayFieldOffset = unsafe.objectFieldOffset
(AtomicReferenceArray.class.getDeclaredField("array"));
base = unsafe.arrayBaseOffset(Object[].class);
scale = unsafe.arrayIndexScale(Object[].class);
} catch (Exception e) {
throw new Error(e);
}
if ((scale & (scale - 1)) != 0)
throw new Error("data type scale not a power of two");
shift = 31 - Integer.numberOfLeadingZeros(scale);
@ -91,7 +103,7 @@ public class AtomicReferenceArray<E> implements java.io.Serializable {
*/
public AtomicReferenceArray(E[] array) {
// Visibility guaranteed by final field guarantees
this.array = array.clone();
this.array = Arrays.copyOf(array, array.length, Object[].class);
}
/**
@ -150,7 +162,7 @@ public class AtomicReferenceArray<E> implements java.io.Serializable {
public final E getAndSet(int i, E newValue) {
long offset = checkedByteOffset(i);
while (true) {
E current = (E) getRaw(offset);
E current = getRaw(offset);
if (compareAndSetRaw(offset, current, newValue))
return current;
}
@ -196,7 +208,7 @@ public class AtomicReferenceArray<E> implements java.io.Serializable {
* @return the String representation of the current values of array
*/
public String toString() {
int iMax = array.length - 1;
int iMax = array.length - 1;
if (iMax == -1)
return "[]";
@ -210,4 +222,19 @@ public class AtomicReferenceArray<E> implements java.io.Serializable {
}
}
/**
* Reconstitutes the instance from a stream (that is, deserializes it).
* @param s the stream
*/
private void readObject(java.io.ObjectInputStream s)
throws java.io.IOException, ClassNotFoundException {
// Note: This must be changed if any additional fields are defined
Object a = s.readFields().get("array", null);
if (a == null || !a.getClass().isArray())
throw new java.io.InvalidObjectException("Not array type");
if (a.getClass() != Object[].class)
a = Arrays.copyOf((Object[])a, Array.getLength(a), Object[].class);
unsafe.putObjectVolatile(this, arrayFieldOffset, a);
}
}