org.wildfly.security.permission.SimpleActionBitsPermissionCollection Maven / Gradle / Ivy
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* JBoss, Home of Professional Open Source.
* Copyright 2016 Red Hat, Inc., and individual contributors
* as indicated by the @author tags.
*
* 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.
*/
package org.wildfly.security.permission;
import java.security.Permission;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.concurrent.atomic.AtomicReference;
import org.wildfly.security.util.ArrayIterator;
/**
* A trivially simple permission collection, suitable as a default for most permission types (though probably not as efficient
* as a specialized type in many cases).
*
* @author David M. Lloyd
*/
public final class SimpleActionBitsPermissionCollection extends AbstractPermissionCollection {
private static final AbstractActionSetPermission[] NO_PERMS = new AbstractActionSetPermission[0];
private final AtomicReference[]> permissionsRef = new AtomicReference<>(NO_PERMS);
/**
* Construct a new instance.
*
* @param sourcePermission the source permission for this collection (must not be {@code null})
*/
public SimpleActionBitsPermissionCollection(final AbstractActionSetPermission sourcePermission) {
super(sourcePermission);
}
public int size() {
return permissionsRef.get().length;
}
@Override
protected void doAdd(final AbstractPermission permission) {
if (permission instanceof AbstractActionSetPermission) {
doAdd((AbstractActionSetPermission) permission);
}
throw ElytronMessages.log.invalidPermissionType(AbstractActionSetPermission.class, permission);
}
/**
* Adds a permission.
*
* @param permission the non-{@code null} permission
*/
protected void doAdd(final AbstractActionSetPermission permission) {
AbstractActionSetPermission[] oldVal, readVal, newVal;
int count;
final AtomicReference[]> permissionsRef = this.permissionsRef;
do {
readVal = permissionsRef.get();
count = 0;
do {
oldVal = readVal;
AbstractActionSetPermission merged = permission;
retry: for (;;) {
for (AbstractActionSetPermission test : oldVal) {
if (test.implies(merged)) {
// fail fast
return;
}
if (test.nameEquals(merged)) {
// combine
merged = merged.withActionBits(permission.getActionBits());
// test again with merged permission
count = 0;
continue retry;
}
if (! merged.implies(test)) {
// prepare to skip any permissions that are obviated by this one
count ++;
}
}
break;
}
// see if it's still what we expect before we commit to the possibly expensive update...
readVal = permissionsRef.get();
} while (readVal != oldVal);
newVal = new AbstractActionSetPermission[count + 1];
int i = 0;
for (AbstractActionSetPermission test : oldVal) {
if (! permission.implies(test)) {
newVal[i++] = test;
}
}
newVal[i] = permission;
} while (! permissionsRef.compareAndSet(oldVal, newVal));
}
public boolean implies(final Permission permission) {
for (Permission test : permissionsRef.get()) {
if (test.implies(permission)) {
return true;
}
}
return false;
}
public Iterator iterator() {
return new ArrayIterator(permissionsRef.get());
}
public Enumeration elements() {
return new ArrayIterator(permissionsRef.get());
}
}