/*
* Copyright 2013 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.spdy;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.NoSuchElementException;
import java.util.Set;
import java.util.TreeSet;
public class DefaultSpdyHeaders extends SpdyHeaders {
private static final int BUCKET_SIZE = 17;
private static int hash(String name) {
int h = 0;
for (int i = name.length() - 1; i >= 0; i --) {
char c = name.charAt(i);
if (c >= 'A' && c <= 'Z') {
c += 32;
}
h = 31 * h + c;
}
if (h > 0) {
return h;
} else if (h == Integer.MIN_VALUE) {
return Integer.MAX_VALUE;
} else {
return -h;
}
}
private static boolean eq(String name1, String name2) {
int nameLen = name1.length();
if (nameLen != name2.length()) {
return false;
}
for (int i = nameLen - 1; i >= 0; i --) {
char c1 = name1.charAt(i);
char c2 = name2.charAt(i);
if (c1 != c2) {
if (c1 >= 'A' && c1 <= 'Z') {
c1 += 32;
}
if (c2 >= 'A' && c2 <= 'Z') {
c2 += 32;
}
if (c1 != c2) {
return false;
}
}
}
return true;
}
private static int index(int hash) {
return hash % BUCKET_SIZE;
}
private final HeaderEntry[] entries = new HeaderEntry[BUCKET_SIZE];
private final HeaderEntry head = new HeaderEntry(-1, null, null);
DefaultSpdyHeaders() {
head.before = head.after = head;
}
@Override
public SpdyHeaders add(final String name, final Object value) {
String lowerCaseName = name.toLowerCase();
SpdyCodecUtil.validateHeaderName(lowerCaseName);
String strVal = toString(value);
SpdyCodecUtil.validateHeaderValue(strVal);
int h = hash(lowerCaseName);
int i = index(h);
add0(h, i, lowerCaseName, strVal);
return this;
}
private void add0(int h, int i, final String name, final String value) {
// Update the hash table.
HeaderEntry e = entries[i];
HeaderEntry newEntry;
entries[i] = newEntry = new HeaderEntry(h, name, value);
newEntry.next = e;
// Update the linked list.
newEntry.addBefore(head);
}
@Override
public SpdyHeaders remove(final String name) {
if (name == null) {
throw new NullPointerException("name");
}
String lowerCaseName = name.toLowerCase();
int h = hash(lowerCaseName);
int i = index(h);
remove0(h, i, lowerCaseName);
return this;
}
private void remove0(int h, int i, String name) {
HeaderEntry e = entries[i];
if (e == null) {
return;
}
for (;;) {
if (e.hash == h && eq(name, e.key)) {
e.remove();
HeaderEntry next = e.next;
if (next != null) {
entries[i] = next;
e = next;
} else {
entries[i] = null;
return;
}
} else {
break;
}
}
for (;;) {
HeaderEntry next = e.next;
if (next == null) {
break;
}
if (next.hash == h && eq(name, next.key)) {
e.next = next.next;
next.remove();
} else {
e = next;
}
}
}
@Override
public SpdyHeaders set(final String name, final Object value) {
String lowerCaseName = name.toLowerCase();
SpdyCodecUtil.validateHeaderName(lowerCaseName);
String strVal = toString(value);
SpdyCodecUtil.validateHeaderValue(strVal);
int h = hash(lowerCaseName);
int i = index(h);
remove0(h, i, lowerCaseName);
add0(h, i, lowerCaseName, strVal);
return this;
}
@Override
public SpdyHeaders set(final String name, final Iterable<?> values) {
if (values == null) {
throw new NullPointerException("values");
}
String lowerCaseName = name.toLowerCase();
SpdyCodecUtil.validateHeaderName(lowerCaseName);
int h = hash(lowerCaseName);
int i = index(h);
remove0(h, i, lowerCaseName);
for (Object v: values) {
if (v == null) {
break;
}
String strVal = toString(v);
SpdyCodecUtil.validateHeaderValue(strVal);
add0(h, i, lowerCaseName, strVal);
}
return this;
}
@Override
public SpdyHeaders clear() {
for (int i = 0; i < entries.length; i ++) {
entries[i] = null;
}
head.before = head.after = head;
return this;
}
@Override
public String get(final String name) {
if (name == null) {
throw new NullPointerException("name");
}
int h = hash(name);
int i = index(h);
HeaderEntry e = entries[i];
while (e != null) {
if (e.hash == h && eq(name, e.key)) {
return e.value;
}
e = e.next;
}
return null;
}
@Override
public List<String> getAll(final String name) {
if (name == null) {
throw new NullPointerException("name");
}
LinkedList<String> values = new LinkedList<String>();
int h = hash(name);
int i = index(h);
HeaderEntry e = entries[i];
while (e != null) {
if (e.hash == h && eq(name, e.key)) {
values.addFirst(e.value);
}
e = e.next;
}
return values;
}
@Override
public List<Map.Entry<String, String>> entries() {
List<Map.Entry<String, String>> all =
new LinkedList<Map.Entry<String, String>>();
HeaderEntry e = head.after;
while (e != head) {
all.add(e);
e = e.after;
}
return all;
}
@Override
public Iterator<Map.Entry<String, String>> iterator() {
return new HeaderIterator();
}
@Override
public boolean contains(String name) {
return get(name) != null;
}
@Override
public Set<String> names() {
Set<String> names = new TreeSet<String>();
HeaderEntry e = head.after;
while (e != head) {
names.add(e.key);
e = e.after;
}
return names;
}
@Override
public SpdyHeaders add(String name, Iterable<?> values) {
SpdyCodecUtil.validateHeaderValue(name);
int h = hash(name);
int i = index(h);
for (Object v: values) {
String vstr = toString(v);
SpdyCodecUtil.validateHeaderValue(vstr);
add0(h, i, name, vstr);
}
return this;
}
@Override
public boolean isEmpty() {
return head == head.after;
}
private static String toString(Object value) {
if (value == null) {
return null;
}
return value.toString();
}
private final class HeaderIterator implements Iterator<Map.Entry<String, String>> {
private HeaderEntry current = head;
@Override
public boolean hasNext() {
return current.after != head;
}
@Override
public Entry<String, String> next() {
current = current.after;
if (current == head) {
throw new NoSuchElementException();
}
return current;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
}
private static final class HeaderEntry implements Map.Entry<String, String> {
final int hash;
final String key;
String value;
HeaderEntry next;
HeaderEntry before, after;
HeaderEntry(int hash, String key, String value) {
this.hash = hash;
this.key = key;
this.value = value;
}
void remove() {
before.after = after;
after.before = before;
}
void addBefore(HeaderEntry e) {
after = e;
before = e.before;
before.after = this;
after.before = this;
}
@Override
public String getKey() {
return key;
}
@Override
public String getValue() {
return value;
}
@Override
public String setValue(String value) {
if (value == null) {
throw new NullPointerException("value");
}
SpdyCodecUtil.validateHeaderValue(value);
String oldValue = this.value;
this.value = value;
return oldValue;
}
@Override
public String toString() {
return key + '=' + value;
}
}
}