org.apache.hadoop.hive.common.DiskRangeList 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.
*/
package org.apache.hadoop.hive.common;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import com.google.common.annotations.VisibleForTesting;
/** Java linked list iterator interface is convoluted, and moreover concurrent modifications
* of the same list by multiple iterators are impossible. Hence, this.
* Java also doesn't support multiple inheritance, so this cannot be done as "aspect"... */
public class DiskRangeList extends DiskRange {
private static final Log LOG = LogFactory.getLog(DiskRangeList.class);
public DiskRangeList prev, next;
public DiskRangeList(long offset, long end) {
super(offset, end);
}
/** Replaces this element with another in the list; returns the new element. */
public DiskRangeList replaceSelfWith(DiskRangeList other) {
other.prev = this.prev;
other.next = this.next;
if (this.prev != null) {
this.prev.next = other;
}
if (this.next != null) {
this.next.prev = other;
}
this.next = this.prev = null;
return other;
}
/**
* Inserts an intersecting range before current in the list and adjusts offset accordingly.
* @returns the new element.
*/
public DiskRangeList insertPartBefore(DiskRangeList other) {
assert other.end >= this.offset;
this.offset = other.end;
other.prev = this.prev;
other.next = this;
if (this.prev != null) {
this.prev.next = other;
}
this.prev = other;
return other;
}
/**
* Inserts an element after current in the list.
* @returns the new element.
* */
public DiskRangeList insertAfter(DiskRangeList other) {
other.next = this.next;
other.prev = this;
if (this.next != null) {
this.next.prev = other;
}
this.next = other;
return other;
}
/**
* Inserts an intersecting range after current in the list and adjusts offset accordingly.
* @returns the new element.
*/
public DiskRangeList insertPartAfter(DiskRangeList other) {
assert other.offset <= this.end;
this.end = other.offset;
return insertAfter(other);
}
/** Removes an element after current from the list. */
public void removeAfter() {
DiskRangeList other = this.next;
this.next = other.next;
if (this.next != null) {
this.next.prev = this;
}
other.next = other.prev = null;
}
/** Removes the current element from the list. */
public void removeSelf() {
if (this.prev != null) {
this.prev.next = this.next;
}
if (this.next != null) {
this.next.prev = this.prev;
}
this.next = this.prev = null;
}
/** Splits current element in the list, using DiskRange::slice */
public DiskRangeList split(long cOffset) {
insertAfter((DiskRangeList)this.sliceAndShift(cOffset, end, 0));
return replaceSelfWith((DiskRangeList)this.sliceAndShift(offset, cOffset, 0));
}
public boolean hasContiguousNext() {
return next != null && end == next.offset;
}
@VisibleForTesting
public int listSize() {
int result = 1;
DiskRangeList current = this.next;
while (current != null) {
++result;
current = current.next;
}
return result;
}
@VisibleForTesting
public DiskRangeList[] listToArray() {
DiskRangeList[] result = new DiskRangeList[listSize()];
int i = 0;
DiskRangeList current = this.next;
while (current != null) {
result[i] = current;
++i;
current = current.next;
}
return result;
}
public static class DiskRangeListCreateHelper {
private DiskRangeList tail = null, head;
public DiskRangeListCreateHelper() {
}
public DiskRangeList getTail() {
return tail;
}
public void addOrMerge(long offset, long end, boolean doMerge, boolean doLogNew) {
if (doMerge && tail != null && tail.merge(offset, end)) return;
if (doLogNew) {
LOG.info("Creating new range; last range (which can include some previous adds) was "
+ tail);
}
DiskRangeList node = new DiskRangeList(offset, end);
if (tail == null) {
head = tail = node;
} else {
tail = tail.insertAfter(node);
}
}
public DiskRangeList get() {
return head;
}
public DiskRangeList extract() {
DiskRangeList result = head;
head = null;
return result;
}
}
/**
* List in-place mutation helper - a bogus first element that is inserted before list head,
* and thus remains constant even if head is replaced with some new range via in-place list
* mutation. extract() can be used to obtain the modified list.
*/
public static class DiskRangeListMutateHelper extends DiskRangeList {
public DiskRangeListMutateHelper(DiskRangeList head) {
super(-1, -1);
assert head != null;
assert head.prev == null;
this.next = head;
head.prev = this;
}
public DiskRangeList get() {
return next;
}
public DiskRangeList extract() {
DiskRangeList result = this.next;
assert result != null;
this.next = result.prev = null;
return result;
}
}
}