/*
* JBoss, Home of Professional Open Source.
*
* Copyright 2012 Red Hat, Inc. and/or its affiliates, 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 io.undertow.conduits;
import io.undertow.UndertowLogger;
import io.undertow.UndertowMessages;
import io.undertow.server.HttpServerExchange;
import org.xnio.channels.StreamSinkChannel;
import org.xnio.conduits.AbstractStreamSourceConduit;
import org.xnio.conduits.StreamSourceConduit;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.util.concurrent.TimeUnit;
import static java.lang.Math.min;
import static org.xnio.Bits.allAreClear;
import static org.xnio.Bits.allAreSet;
import static org.xnio.Bits.anyAreClear;
import static org.xnio.Bits.anyAreSet;
import static org.xnio.Bits.longBitMask;
/**
* A channel which reads data of a fixed length and calls a finish listener. When the finish listener is called,
* it should examine the result of {@link #getRemaining()} to see if more bytes were pending when the channel was
* closed.
*
* @author <a href="mailto:david.lloyd@redhat.com">David M. Lloyd</a>
*/
/*
* Implementation notes
* --------------------
* The {@code exhausted} flag is set once a method returns -1 and signifies that the read listener should no longer be
* called. The {@code finishListener} is called when remaining is reduced to 0 or when the channel is closed explicitly.
* If there are 0 remaining bytes but {@code FLAG_FINISHED} has not yet been set, the channel is considered "ready" until
* the EOF -1 value is read or the channel is closed. Since this is a half-duplex channel, shutting down reads is
* identical to closing the channel.
*/
public final class FixedLengthStreamSourceConduit extends AbstractStreamSourceConduit<StreamSourceConduit> {
private final ConduitListener<? super FixedLengthStreamSourceConduit> finishListener;
@SuppressWarnings("unused")
private long state;
private static final long FLAG_CLOSED = 1L << 63L;
private static final long FLAG_FINISHED = 1L << 62L;
private static final long FLAG_LENGTH_CHECKED = 1L << 61L;
private static final long MASK_COUNT = longBitMask(0, 60);
private final HttpServerExchange exchange;
/**
* Construct a new instance. The given listener is called once all the bytes are read from the stream
* <b>or</b> the stream is closed. This listener should cause the remaining data to be drained from the
* underlying stream if the underlying stream is to be reused.
* <p/>
* Calling this constructor will replace the read listener of the underlying channel. The listener should be
* restored from the {@code finishListener} object. The underlying stream should not be closed while this wrapper
* stream is active.
*
* @param next the stream source channel to read from
* @param contentLength the amount of content to read
* @param finishListener the listener to call once the stream is exhausted or closed
* @param exchange The server exchange. This is used to determine the max size
*/
public FixedLengthStreamSourceConduit(final StreamSourceConduit next, final long contentLength, final ConduitListener<? super FixedLengthStreamSourceConduit> finishListener, final HttpServerExchange exchange) {
super(next);
this.finishListener = finishListener;
if (contentLength < 0L) {
throw new IllegalArgumentException("Content length must be greater than or equal to zero");
} else if (contentLength > MASK_COUNT) {
throw new IllegalArgumentException("Content length is too long");
}
state = contentLength;
this.exchange = exchange;
}
/**
* Construct a new instance. The given listener is called once all the bytes are read from the stream
* <b>or</b> the stream is closed. This listener should cause the remaining data to be drained from the
* underlying stream if the underlying stream is to be reused.
* <p/>
* Calling this constructor will replace the read listener of the underlying channel. The listener should be
* restored from the {@code finishListener} object. The underlying stream should not be closed while this wrapper
* stream is active.
*
* @param next the stream source channel to read from
* @param contentLength the amount of content to read
* @param finishListener the listener to call once the stream is exhausted or closed
*/
public FixedLengthStreamSourceConduit(final StreamSourceConduit next, final long contentLength, final ConduitListener<? super FixedLengthStreamSourceConduit> finishListener) {
this(next, contentLength, finishListener, null);
}
public long transferTo(final long position, final long count, final FileChannel target) throws IOException {
long val = state;
checkMaxSize(val);
if (anyAreSet(val, FLAG_CLOSED | FLAG_FINISHED) || allAreClear(val, MASK_COUNT)) {
if (allAreClear(val, FLAG_FINISHED)) {
invokeFinishListener();
}
return -1L;
}
long res = 0L;
try {
return res = next.transferTo(position, min(count, val & MASK_COUNT), target);
} finally {
exitRead(res);
}
}
public long transferTo(final long count, final ByteBuffer throughBuffer, final StreamSinkChannel target) throws IOException {
if (count == 0L) {
return 0L;
}
long val = state;
checkMaxSize(val);
if (anyAreSet(val, FLAG_CLOSED | FLAG_FINISHED) || allAreClear(val, MASK_COUNT)) {
if (allAreClear(val, FLAG_FINISHED)) {
invokeFinishListener();
}
return -1;
}
long res = 0L;
try {
return res = next.transferTo(min(count, val & MASK_COUNT), throughBuffer, target);
} finally {
exitRead(res == -1L ? val & MASK_COUNT : res + throughBuffer.remaining());
}
}
private void checkMaxSize(long state) throws IOException {
if (anyAreClear(state, FLAG_LENGTH_CHECKED)) {
HttpServerExchange exchange = this.exchange;
if (exchange != null) {
if (exchange.getMaxEntitySize() > 0 && exchange.getMaxEntitySize() < (state & MASK_COUNT)) {
//max entity size is exceeded
//we need to forcibly close the read side
try {
next.terminateReads();
} catch (IOException e) {
UndertowLogger.REQUEST_LOGGER.debug("Exception terminating reads due to exceeding max size", e);
}
finishListener.handleEvent(this);
state |= FLAG_FINISHED | FLAG_CLOSED;
exchange.setPersistent(false);
throw UndertowMessages.MESSAGES.requestEntityWasTooLarge(exchange.getMaxEntitySize());
}
}
this.state |= FLAG_LENGTH_CHECKED;
}
}
public long read(final ByteBuffer[] dsts, final int offset, final int length) throws IOException {
if (length == 0) {
return 0L;
} else if (length == 1) {
return read(dsts[offset]);
}
long val = state;
checkMaxSize(val);
if (allAreSet(val, FLAG_CLOSED) || allAreClear(val, MASK_COUNT)) {
if (allAreClear(val, FLAG_FINISHED)) {
invokeFinishListener();
}
return -1;
}
long res = 0L;
try {
if ((val & MASK_COUNT) == 0L) {
return -1L;
}
int lim;
// The total amount of buffer space discovered so far.
long t = 0L;
for (int i = 0; i < length; i++) {
final ByteBuffer buffer = dsts[i + offset];
// Grow the discovered buffer space by the remaining size of the current buffer.
// We want to capture the limit so we calculate "remaining" ourselves.
t += (lim = buffer.limit()) - buffer.position();
if (t > (val & MASK_COUNT)) {
// only read up to this point, and trim the last buffer by the number of extra bytes
buffer.limit(lim - (int) (t - (val & MASK_COUNT)));
try {
return res = next.read(dsts, offset, i + 1);
} finally {
// restore the original limit
buffer.limit(lim);
}
}
}
// the total buffer space is less than the remaining count.
return res = next.read(dsts, offset, length);
} finally {
exitRead(res == -1L ? val & MASK_COUNT : res);
}
}
public long read(final ByteBuffer[] dsts) throws IOException {
return read(dsts, 0, dsts.length);
}
public int read(final ByteBuffer dst) throws IOException {
long val = state;
checkMaxSize(val);
if (allAreSet(val, FLAG_CLOSED) || allAreClear(val, MASK_COUNT)) {
if (allAreClear(val, FLAG_FINISHED)) {
invokeFinishListener();
}
return -1;
}
int res = 0;
final long remaining = val & MASK_COUNT;
try {
final int lim = dst.limit();
final int pos = dst.position();
if (lim - pos > remaining) {
dst.limit((int) (remaining + (long) pos));
try {
return res = next.read(dst);
} finally {
dst.limit(lim);
}
} else {
return res = next.read(dst);
}
} finally {
exitRead(res == -1 ? remaining : (long) res);
}
}
public boolean isReadResumed() {
return allAreClear(state, FLAG_CLOSED) && next.isReadResumed();
}
public void wakeupReads() {
long val = state;
if (anyAreSet(val, FLAG_CLOSED | FLAG_FINISHED) || allAreClear(val, MASK_COUNT)) {
return;
}
next.wakeupReads();
}
@Override
public void terminateReads() throws IOException {
long val = enterShutdownReads();
if (allAreSet(val, FLAG_CLOSED)) {
return;
}
exitShutdownReads(val);
}
public void awaitReadable() throws IOException {
final long val = state;
if (allAreSet(val, FLAG_CLOSED) || val == 0L) {
return;
}
next.awaitReadable();
}
public void awaitReadable(final long time, final TimeUnit timeUnit) throws IOException {
final long val = state;
if (allAreSet(val, FLAG_CLOSED) || val == 0L) {
return;
}
next.awaitReadable(time, timeUnit);
}
/**
* Get the number of remaining bytes.
*
* @return the number of remaining bytes
*/
public long getRemaining() {
return state & MASK_COUNT;
}
private long enterShutdownReads() {
long oldVal, newVal;
oldVal = state;
if (anyAreSet(oldVal, FLAG_CLOSED)) {
return oldVal;
}
newVal = oldVal | FLAG_CLOSED;
state = newVal;
return oldVal;
}
private void exitShutdownReads(long oldVal) {
if (!allAreClear(oldVal, MASK_COUNT)) {
invokeFinishListener();
}
}
/**
* Exit a read method.
*
* @param consumed the number of bytes consumed by this call (may be 0)
*/
private void exitRead(long consumed) {
long oldVal = state;
long newVal = oldVal - consumed;
state = newVal;
if (anyAreSet(oldVal, MASK_COUNT) && allAreClear(newVal, MASK_COUNT)) {
invokeFinishListener();
}
}
private void invokeFinishListener() {
this.state |= FLAG_FINISHED;
finishListener.handleEvent(this);
}
}