/*
* 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.catalina.connector;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.Objects;
import jakarta.servlet.ServletOutputStream;
import jakarta.servlet.WriteListener;
import org.apache.tomcat.util.res.StringManager;
/**
* Coyote implementation of the servlet output stream.
*/
public class CoyoteOutputStream extends ServletOutputStream {
protected static final StringManager sm = StringManager.getManager(CoyoteOutputStream.class);
// ----------------------------------------------------- Instance Variables
protected OutputBuffer ob;
// ----------------------------------------------------------- Constructors
protected CoyoteOutputStream(OutputBuffer ob) {
this.ob = ob;
}
// --------------------------------------------------------- Public Methods
/**
* Prevent cloning the facade.
*/
@Override
protected Object clone() throws CloneNotSupportedException {
throw new CloneNotSupportedException();
}
// -------------------------------------------------------- Package Methods
/**
* Clear facade.
*/
void clear() {
ob = null;
}
// --------------------------------------------------- OutputStream Methods
@Override
public void write(int i) throws IOException {
boolean nonBlocking = checkNonBlockingWrite();
try {
ob.writeByte(i);
} catch (IOException ioe) {
handleIOException(ioe);
}
if (nonBlocking) {
checkRegisterForWrite();
}
}
@Override
public void write(byte[] b) throws IOException {
write(b, 0, b.length);
}
@Override
public void write(byte[] b, int off, int len) throws IOException {
boolean nonBlocking = checkNonBlockingWrite();
try {
ob.write(b, off, len);
} catch (IOException ioe) {
handleIOException(ioe);
}
if (nonBlocking) {
checkRegisterForWrite();
}
}
@Override
public void write(ByteBuffer from) throws IOException {
Objects.requireNonNull(from);
boolean nonBlocking = checkNonBlockingWrite();
if (from.remaining() == 0) {
return;
}
try {
ob.write(from);
} catch (IOException ioe) {
handleIOException(ioe);
}
if (nonBlocking) {
checkRegisterForWrite();
}
}
/**
* Will send the buffer to the client.
*/
@Override
public void flush() throws IOException {
boolean nonBlocking = checkNonBlockingWrite();
try {
ob.flush();
} catch (IOException ioe) {
handleIOException(ioe);
}
if (nonBlocking) {
checkRegisterForWrite();
}
}
/**
* Checks for concurrent writes which are not permitted. This object has no state information so the call chain is
* CoyoteOutputStream->OutputBuffer->CoyoteResponse.
*
* @return <code>true</code> if this OutputStream is currently in non-blocking mode.
*/
private boolean checkNonBlockingWrite() {
boolean nonBlocking = !ob.isBlocking();
if (nonBlocking && !ob.isReady()) {
throw new IllegalStateException(sm.getString("coyoteOutputStream.nbNotready"));
}
return nonBlocking;
}
/**
* Checks to see if there is data left in the Coyote output buffers (NOT the servlet output buffer) and if so
* registers the associated socket for write so the buffers will be emptied. The container will take care of this.
* As far as the app is concerned, there is a non-blocking write in progress. It doesn't have visibility of whether
* the data is buffered in the socket buffer or the Coyote buffers.
*/
private void checkRegisterForWrite() {
ob.checkRegisterForWrite();
}
@Override
public void close() throws IOException {
try {
ob.close();
} catch (IOException ioe) {
handleIOException(ioe);
}
}
@Override
public boolean isReady() {
if (ob == null) {
throw new IllegalStateException(sm.getString("coyoteOutputStream.null"));
}
return ob.isReady();
}
@Override
public void setWriteListener(WriteListener listener) {
ob.setWriteListener(listener);
}
private void handleIOException(IOException ioe) throws IOException {
try {
ob.setErrorException(ioe);
} catch (NullPointerException npe) {
/*
* Ignore.
*
* An IOException on a non-container thread during asynchronous Servlet processing will trigger a dispatch
* to a container thread that will complete the asynchronous processing and recycle the request, response
* and associated objects including the OutputBuffer. Depending on timing it is possible that the
* OutputBuffer will have been cleared by the time the call above is made - resulting in an NPE.
*
* If the OutputBuffer is null then there is no need to call setErrorException(). Catching and ignoring the
* NPE is (for now at least) a simpler solution than adding locking to OutputBuffer to ensure it is non-null
* and remains non-null while setErrorException() is called.
*
* The longer term solution is likely a refactoring and clean-up of error handling for asynchronous requests
* but that is potentially a significant piece of work.
*/
}
throw ioe;
}
}