/*
 * Copyright 2015 The Netty Project
 *
 * The Netty Project 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 io.netty.handler.codec.dns;

import io.netty.util.AbstractReferenceCounted;
import io.netty.util.ReferenceCountUtil;
import io.netty.util.ReferenceCounted;
import io.netty.util.ResourceLeakDetector;
import io.netty.util.ResourceLeakDetectorFactory;
import io.netty.util.ResourceLeakTracker;
import io.netty.util.internal.StringUtil;
import io.netty.util.internal.UnstableApi;

import java.util.ArrayList;
import java.util.List;

import static io.netty.util.internal.ObjectUtil.checkNotNull;

A skeletal implementation of DnsMessage.
/** * A skeletal implementation of {@link DnsMessage}. */
@UnstableApi public abstract class AbstractDnsMessage extends AbstractReferenceCounted implements DnsMessage { private static final ResourceLeakDetector<DnsMessage> leakDetector = ResourceLeakDetectorFactory.instance().newResourceLeakDetector(DnsMessage.class); private static final int SECTION_QUESTION = DnsSection.QUESTION.ordinal(); private static final int SECTION_COUNT = 4; private final ResourceLeakTracker<DnsMessage> leak = leakDetector.track(this); private short id; private DnsOpCode opCode; private boolean recursionDesired; private byte z; // To reduce the memory footprint of a message, // each of the following fields is a single record or a list of records. private Object questions; private Object answers; private Object authorities; private Object additionals;
Creates a new instance with the specified id and DnsOpCode.QUERY opCode.
/** * Creates a new instance with the specified {@code id} and {@link DnsOpCode#QUERY} opCode. */
protected AbstractDnsMessage(int id) { this(id, DnsOpCode.QUERY); }
Creates a new instance with the specified id and opCode.
/** * Creates a new instance with the specified {@code id} and {@code opCode}. */
protected AbstractDnsMessage(int id, DnsOpCode opCode) { setId(id); setOpCode(opCode); } @Override public int id() { return id & 0xFFFF; } @Override public DnsMessage setId(int id) { this.id = (short) id; return this; } @Override public DnsOpCode opCode() { return opCode; } @Override public DnsMessage setOpCode(DnsOpCode opCode) { this.opCode = checkNotNull(opCode, "opCode"); return this; } @Override public boolean isRecursionDesired() { return recursionDesired; } @Override public DnsMessage setRecursionDesired(boolean recursionDesired) { this.recursionDesired = recursionDesired; return this; } @Override public int z() { return z; } @Override public DnsMessage setZ(int z) { this.z = (byte) (z & 7); return this; } @Override public int count(DnsSection section) { return count(sectionOrdinal(section)); } private int count(int section) { final Object records = sectionAt(section); if (records == null) { return 0; } if (records instanceof DnsRecord) { return 1; } @SuppressWarnings("unchecked") final List<DnsRecord> recordList = (List<DnsRecord>) records; return recordList.size(); } @Override public int count() { int count = 0; for (int i = 0; i < SECTION_COUNT; i ++) { count += count(i); } return count; } @Override public <T extends DnsRecord> T recordAt(DnsSection section) { return recordAt(sectionOrdinal(section)); } private <T extends DnsRecord> T recordAt(int section) { final Object records = sectionAt(section); if (records == null) { return null; } if (records instanceof DnsRecord) { return castRecord(records); } @SuppressWarnings("unchecked") final List<DnsRecord> recordList = (List<DnsRecord>) records; if (recordList.isEmpty()) { return null; } return castRecord(recordList.get(0)); } @Override public <T extends DnsRecord> T recordAt(DnsSection section, int index) { return recordAt(sectionOrdinal(section), index); } private <T extends DnsRecord> T recordAt(int section, int index) { final Object records = sectionAt(section); if (records == null) { throw new IndexOutOfBoundsException("index: " + index + " (expected: none)"); } if (records instanceof DnsRecord) { if (index == 0) { return castRecord(records); } else { throw new IndexOutOfBoundsException("index: " + index + "' (expected: 0)"); } } @SuppressWarnings("unchecked") final List<DnsRecord> recordList = (List<DnsRecord>) records; return castRecord(recordList.get(index)); } @Override public DnsMessage setRecord(DnsSection section, DnsRecord record) { setRecord(sectionOrdinal(section), record); return this; } private void setRecord(int section, DnsRecord record) { clear(section); setSection(section, checkQuestion(section, record)); } @Override public <T extends DnsRecord> T setRecord(DnsSection section, int index, DnsRecord record) { return setRecord(sectionOrdinal(section), index, record); } private <T extends DnsRecord> T setRecord(int section, int index, DnsRecord record) { checkQuestion(section, record); final Object records = sectionAt(section); if (records == null) { throw new IndexOutOfBoundsException("index: " + index + " (expected: none)"); } if (records instanceof DnsRecord) { if (index == 0) { setSection(section, record); return castRecord(records); } else { throw new IndexOutOfBoundsException("index: " + index + " (expected: 0)"); } } @SuppressWarnings("unchecked") final List<DnsRecord> recordList = (List<DnsRecord>) records; return castRecord(recordList.set(index, record)); } @Override public DnsMessage addRecord(DnsSection section, DnsRecord record) { addRecord(sectionOrdinal(section), record); return this; } private void addRecord(int section, DnsRecord record) { checkQuestion(section, record); final Object records = sectionAt(section); if (records == null) { setSection(section, record); return; } if (records instanceof DnsRecord) { final List<DnsRecord> recordList = newRecordList(); recordList.add(castRecord(records)); recordList.add(record); setSection(section, recordList); return; } @SuppressWarnings("unchecked") final List<DnsRecord> recordList = (List<DnsRecord>) records; recordList.add(record); } @Override public DnsMessage addRecord(DnsSection section, int index, DnsRecord record) { addRecord(sectionOrdinal(section), index, record); return this; } private void addRecord(int section, int index, DnsRecord record) { checkQuestion(section, record); final Object records = sectionAt(section); if (records == null) { if (index != 0) { throw new IndexOutOfBoundsException("index: " + index + " (expected: 0)"); } setSection(section, record); return; } if (records instanceof DnsRecord) { final List<DnsRecord> recordList; if (index == 0) { recordList = newRecordList(); recordList.add(record); recordList.add(castRecord(records)); } else if (index == 1) { recordList = newRecordList(); recordList.add(castRecord(records)); recordList.add(record); } else { throw new IndexOutOfBoundsException("index: " + index + " (expected: 0 or 1)"); } setSection(section, recordList); return; } @SuppressWarnings("unchecked") final List<DnsRecord> recordList = (List<DnsRecord>) records; recordList.add(index, record); } @Override public <T extends DnsRecord> T removeRecord(DnsSection section, int index) { return removeRecord(sectionOrdinal(section), index); } private <T extends DnsRecord> T removeRecord(int section, int index) { final Object records = sectionAt(section); if (records == null) { throw new IndexOutOfBoundsException("index: " + index + " (expected: none)"); } if (records instanceof DnsRecord) { if (index != 0) { throw new IndexOutOfBoundsException("index: " + index + " (expected: 0)"); } T record = castRecord(records); setSection(section, null); return record; } @SuppressWarnings("unchecked") final List<DnsRecord> recordList = (List<DnsRecord>) records; return castRecord(recordList.remove(index)); } @Override public DnsMessage clear(DnsSection section) { clear(sectionOrdinal(section)); return this; } @Override public DnsMessage clear() { for (int i = 0; i < SECTION_COUNT; i ++) { clear(i); } return this; } private void clear(int section) { final Object recordOrList = sectionAt(section); setSection(section, null); if (recordOrList instanceof ReferenceCounted) { ((ReferenceCounted) recordOrList).release(); } else if (recordOrList instanceof List) { @SuppressWarnings("unchecked") List<DnsRecord> list = (List<DnsRecord>) recordOrList; if (!list.isEmpty()) { for (Object r : list) { ReferenceCountUtil.release(r); } } } } @Override public DnsMessage touch() { return (DnsMessage) super.touch(); } @Override public DnsMessage touch(Object hint) { if (leak != null) { leak.record(hint); } return this; } @Override public DnsMessage retain() { return (DnsMessage) super.retain(); } @Override public DnsMessage retain(int increment) { return (DnsMessage) super.retain(increment); } @Override protected void deallocate() { clear(); final ResourceLeakTracker<DnsMessage> leak = this.leak; if (leak != null) { boolean closed = leak.close(this); assert closed; } } @Override public boolean equals(Object obj) { if (this == obj) { return true; } if (!(obj instanceof DnsMessage)) { return false; } final DnsMessage that = (DnsMessage) obj; if (id() != that.id()) { return false; } if (this instanceof DnsQuery) { if (!(that instanceof DnsQuery)) { return false; } } else if (that instanceof DnsQuery) { return false; } return true; } @Override public int hashCode() { return id() * 31 + (this instanceof DnsQuery? 0 : 1); } private Object sectionAt(int section) { switch (section) { case 0: return questions; case 1: return answers; case 2: return authorities; case 3: return additionals; } throw new Error(); // Should never reach here. } private void setSection(int section, Object value) { switch (section) { case 0: questions = value; return; case 1: answers = value; return; case 2: authorities = value; return; case 3: additionals = value; return; } throw new Error(); // Should never reach here. } private static int sectionOrdinal(DnsSection section) { return checkNotNull(section, "section").ordinal(); } private static DnsRecord checkQuestion(int section, DnsRecord record) { if (section == SECTION_QUESTION && !(checkNotNull(record, "record") instanceof DnsQuestion)) { throw new IllegalArgumentException( "record: " + record + " (expected: " + StringUtil.simpleClassName(DnsQuestion.class) + ')'); } return record; } @SuppressWarnings("unchecked") private static <T extends DnsRecord> T castRecord(Object record) { return (T) record; } private static ArrayList<DnsRecord> newRecordList() { return new ArrayList<DnsRecord>(2); } }