OutputBuffer.java
/*
* 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.io.Writer;
import java.nio.Buffer;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
import java.security.AccessController;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.WriteListener;
import javax.servlet.http.HttpServletResponse;
import org.apache.catalina.Globals;
import org.apache.coyote.ActionCode;
import org.apache.coyote.CloseNowException;
import org.apache.coyote.Response;
import org.apache.tomcat.util.buf.B2CConverter;
import org.apache.tomcat.util.buf.C2BConverter;
import org.apache.tomcat.util.res.StringManager;
/**
* The buffer used by Tomcat response. This is a derivative of the Tomcat 3.3 OutputBuffer, with the removal of some of
* the state handling (which in Coyote is mostly the Processor's responsibility).
*
* @author Costin Manolache
* @author Remy Maucherat
*/
public class OutputBuffer extends Writer {
private static final StringManager sm = StringManager.getManager(OutputBuffer.class);
public static final int DEFAULT_BUFFER_SIZE = 8 * 1024;
/**
* Encoder cache.
*/
private final Map<Charset,C2BConverter> encoders = new HashMap<>();
/**
* Default buffer size.
*/
private final int defaultBufferSize;
// ----------------------------------------------------- Instance Variables
/**
* The byte buffer.
*/
private ByteBuffer bb;
/**
* The char buffer.
*/
private final CharBuffer cb;
/**
* State of the output buffer.
*/
private boolean initial = true;
/**
* Number of bytes written.
*/
private long bytesWritten = 0;
/**
* Number of chars written.
*/
private long charsWritten = 0;
/**
* Flag which indicates if the output buffer is closed.
*/
private volatile boolean closed = false;
/**
* Do a flush on the next operation.
*/
private boolean doFlush = false;
/**
* Current char to byte converter.
*/
protected C2BConverter conv;
/**
* Associated Coyote response.
*/
private Response coyoteResponse;
/**
* Suspended flag. All output bytes will be swallowed if this is true.
*/
private volatile boolean suspended = false;
// ----------------------------------------------------------- Constructors
/**
* Create the buffer with the specified initial size.
*
* @param size Buffer size to use
*/
public OutputBuffer(int size) {
defaultBufferSize = size;
bb = ByteBuffer.allocate(size);
clear(bb);
cb = CharBuffer.allocate(size);
clear(cb);
}
// ------------------------------------------------------------- Properties
/**
* Associated Coyote response.
*
* @param coyoteResponse Associated Coyote response
*/
public void setResponse(Response coyoteResponse) {
this.coyoteResponse = coyoteResponse;
}
/**
* Is the response output suspended ?
*
* @return suspended flag value
*/
public boolean isSuspended() {
return this.suspended;
}
/**
* Set the suspended flag.
*
* @param suspended New suspended flag value
*/
public void setSuspended(boolean suspended) {
this.suspended = suspended;
}
/**
* Is the response output closed ?
*
* @return closed flag value
*/
public boolean isClosed() {
return this.closed;
}
// --------------------------------------------------------- Public Methods
/**
* Recycle the output buffer.
*/
public void recycle() {
initial = true;
bytesWritten = 0;
charsWritten = 0;
if (bb.capacity() > 16 * defaultBufferSize) {
// Discard buffers which are too large
bb = ByteBuffer.allocate(defaultBufferSize);
}
clear(bb);
clear(cb);
closed = false;
suspended = false;
doFlush = false;
if (conv != null) {
conv.recycle();
conv = null;
}
}
/**
* Close the output buffer. This tries to calculate the response size if the response has not been committed yet.
*
* @throws IOException An underlying IOException occurred
*/
@Override
public void close() throws IOException {
if (closed) {
return;
}
if (suspended) {
return;
}
// If there are chars, flush all of them to the byte buffer now as bytes are used to
// calculate the content-length (if everything fits into the byte buffer, of course).
if (cb.remaining() > 0) {
flushCharBuffer();
}
if ((!coyoteResponse.isCommitted()) && (coyoteResponse.getContentLengthLong() == -1) &&
!coyoteResponse.getRequest().method().equals("HEAD")) {
// If this didn't cause a commit of the response, the final content
// length can be calculated. Only do this if this is not a HEAD
// request since in that case no body should have been written and
// setting a value of zero here will result in an explicit content
// length of zero being set on the response.
coyoteResponse.setContentLength(bb.remaining());
}
if (coyoteResponse.getStatus() == HttpServletResponse.SC_SWITCHING_PROTOCOLS) {
doFlush(true);
} else {
doFlush(false);
}
closed = true;
// The request should have been completely read by the time the response
// is closed. Further reads of the input a) are pointless and b) really
// confuse AJP (bug 50189) so close the input buffer to prevent them.
Request req = (Request) coyoteResponse.getRequest().getNote(CoyoteAdapter.ADAPTER_NOTES);
req.inputBuffer.close();
coyoteResponse.action(ActionCode.CLOSE, null);
}
/**
* Flush bytes or chars contained in the buffer.
*
* @throws IOException An underlying IOException occurred
*/
@Override
public void flush() throws IOException {
doFlush(true);
}
/**
* Flush bytes or chars contained in the buffer.
*
* @param realFlush <code>true</code> if this should also cause a real network flush
*
* @throws IOException An underlying IOException occurred
*/
protected void doFlush(boolean realFlush) throws IOException {
if (suspended) {
return;
}
try {
doFlush = true;
if (initial) {
coyoteResponse.sendHeaders();
initial = false;
}
if (cb.remaining() > 0) {
flushCharBuffer();
}
if (bb.remaining() > 0) {
flushByteBuffer();
}
} finally {
doFlush = false;
}
if (realFlush) {
coyoteResponse.action(ActionCode.CLIENT_FLUSH, null);
// If some exception occurred earlier, or if some IOE occurred
// here, notify the servlet with an IOE
if (coyoteResponse.isExceptionPresent()) {
throw new ClientAbortException(coyoteResponse.getErrorException());
}
}
}
// ------------------------------------------------- Bytes Handling Methods
/**
* Sends the buffer data to the client output, checking the state of Response and calling the right interceptors.
*
* @param buf the ByteBuffer to be written to the response
*
* @throws IOException An underlying IOException occurred
*/
public void realWriteBytes(ByteBuffer buf) throws IOException {
if (closed) {
return;
}
// If we really have something to write
if (buf.remaining() > 0) {
// real write to the adapter
try {
coyoteResponse.doWrite(buf);
} catch (CloseNowException e) {
// Catch this sub-class as it requires specific handling.
// Examples where this exception is thrown:
// - HTTP/2 stream timeout
// Prevent further output for this response
closed = true;
throw e;
} catch (IOException e) {
// An IOException on a write is almost always due to
// the remote client aborting the request. Wrap this
// so that it can be handled better by the error dispatcher.
throw new ClientAbortException(e);
}
}
}
public void write(byte b[], int off, int len) throws IOException {
if (suspended) {
return;
}
writeBytes(b, off, len);
}
public void write(ByteBuffer from) throws IOException {
if (suspended) {
return;
}
writeBytes(from);
}
private void writeBytes(byte b[], int off, int len) throws IOException {
if (closed) {
return;
}
append(b, off, len);
bytesWritten += len;
// if called from within flush(), then immediately flush
// remaining bytes
if (doFlush) {
flushByteBuffer();
}
}
private void writeBytes(ByteBuffer from) throws IOException {
if (closed) {
return;
}
int remaining = from.remaining();
append(from);
bytesWritten += remaining;
// if called from within flush(), then immediately flush
// remaining bytes
if (doFlush) {
flushByteBuffer();
}
}
public void writeByte(int b) throws IOException {
if (suspended) {
return;
}
if (isFull(bb)) {
flushByteBuffer();
}
transfer((byte) b, bb);
bytesWritten++;
}
// ------------------------------------------------- Chars Handling Methods
/**
* Convert the chars to bytes, then send the data to the client.
*
* @param from Char buffer to be written to the response
*
* @throws IOException An underlying IOException occurred
*/
public void realWriteChars(CharBuffer from) throws IOException {
while (from.remaining() > 0) {
conv.convert(from, bb);
if (bb.remaining() == 0) {
// Break out of the loop if more chars are needed to produce any output
break;
}
if (from.remaining() > 0) {
flushByteBuffer();
} else if (conv.isUndeflow() && bb.limit() > bb.capacity() - 4) {
// Handle an edge case. There are no more chars to write at the
// moment but there is a leftover character in the converter
// which must be part of a surrogate pair. The byte buffer does
// not have enough space left to output the bytes for this pair
// once it is complete )it will require 4 bytes) so flush now to
// prevent the bytes for the leftover char and the rest of the
// surrogate pair yet to be written from being lost.
// See TestOutputBuffer#testUtf8SurrogateBody()
flushByteBuffer();
}
}
}
@Override
public void write(int c) throws IOException {
if (suspended) {
return;
}
if (isFull(cb)) {
flushCharBuffer();
}
transfer((char) c, cb);
charsWritten++;
}
@Override
public void write(char c[]) throws IOException {
if (suspended) {
return;
}
write(c, 0, c.length);
}
@Override
public void write(char c[], int off, int len) throws IOException {
if (suspended) {
return;
}
append(c, off, len);
charsWritten += len;
}
/**
* Append a string to the buffer
*/
@Override
public void write(String s, int off, int len) throws IOException {
if (suspended) {
return;
}
if (s == null) {
throw new NullPointerException(sm.getString("outputBuffer.writeNull"));
}
int sOff = off;
int sEnd = off + len;
while (sOff < sEnd) {
int n = transfer(s, sOff, sEnd - sOff, cb);
sOff += n;
if (sOff < sEnd && isFull(cb)) {
flushCharBuffer();
}
}
charsWritten += len;
}
@Override
public void write(String s) throws IOException {
if (suspended) {
return;
}
if (s == null) {
s = "null";
}
write(s, 0, s.length());
}
public void checkConverter() throws IOException {
if (conv != null) {
return;
}
Charset charset = coyoteResponse.getCharset();
if (charset == null) {
if (coyoteResponse.getCharacterEncoding() != null) {
// setCharacterEncoding() was called with an invalid character set
// Trigger an UnsupportedEncodingException
charset = B2CConverter.getCharset(coyoteResponse.getCharacterEncoding());
}
charset = org.apache.coyote.Constants.DEFAULT_BODY_CHARSET;
}
conv = encoders.get(charset);
if (conv == null) {
conv = createConverter(charset);
encoders.put(charset, conv);
}
}
private static C2BConverter createConverter(final Charset charset) throws IOException {
if (Globals.IS_SECURITY_ENABLED) {
try {
return AccessController.doPrivileged(new PrivilegedCreateConverter(charset));
} catch (PrivilegedActionException ex) {
Exception e = ex.getException();
if (e instanceof IOException) {
throw (IOException) e;
} else {
throw new IOException(ex);
}
}
} else {
return new C2BConverter(charset);
}
}
// -------------------- BufferedOutputStream compatibility
public long getContentWritten() {
return bytesWritten + charsWritten;
}
/**
* Has this buffer been used at all?
*
* @return true if no chars or bytes have been added to the buffer since the last call to {@link #recycle()}
*/
public boolean isNew() {
return (bytesWritten == 0) && (charsWritten == 0);
}
public void setBufferSize(int size) {
if (size > bb.capacity()) {
bb = ByteBuffer.allocate(size);
clear(bb);
}
}
public void reset() {
reset(false);
}
public void reset(boolean resetWriterStreamFlags) {
clear(bb);
clear(cb);
bytesWritten = 0;
charsWritten = 0;
if (resetWriterStreamFlags) {
if (conv != null) {
conv.recycle();
}
conv = null;
}
initial = true;
}
public int getBufferSize() {
return bb.capacity();
}
/*
* All the non-blocking write state information is held in the Response so it is visible / accessible to all the
* code that needs it.
*/
public boolean isReady() {
return coyoteResponse.isReady();
}
public void setWriteListener(WriteListener listener) {
coyoteResponse.setWriteListener(listener);
}
public boolean isBlocking() {
return coyoteResponse.getWriteListener() == null;
}
public void checkRegisterForWrite() {
coyoteResponse.checkRegisterForWrite();
}
/**
* Add data to the buffer.
*
* @param src Bytes array
* @param off Offset
* @param len Length
*
* @throws IOException Writing overflow data to the output channel failed
*/
public void append(byte src[], int off, int len) throws IOException {
if (bb.remaining() == 0) {
appendByteArray(src, off, len);
} else {
int n = transfer(src, off, len, bb);
len = len - n;
off = off + n;
if (len > 0 && isFull(bb)) {
flushByteBuffer();
appendByteArray(src, off, len);
}
}
}
/**
* Add data to the buffer.
*
* @param src Char array
* @param off Offset
* @param len Length
*
* @throws IOException Writing overflow data to the output channel failed
*/
public void append(char src[], int off, int len) throws IOException {
// if we have limit and we're below
if (len <= cb.capacity() - cb.limit()) {
transfer(src, off, len, cb);
return;
}
// Optimization:
// If len-avail < length ( i.e. after we fill the buffer with
// what we can, the remaining will fit in the buffer ) we'll just
// copy the first part, flush, then copy the second part - 1 write
// and still have some space for more. We'll still have 2 writes, but
// we write more on the first.
if (len + cb.limit() < 2 * cb.capacity()) {
/*
* If the request length exceeds the size of the output buffer, flush the output buffer and then write the
* data directly. We can't avoid 2 writes, but we can write more on the second
*/
int n = transfer(src, off, len, cb);
flushCharBuffer();
transfer(src, off + n, len - n, cb);
} else {
// long write - flush the buffer and write the rest
// directly from source
flushCharBuffer();
realWriteChars(CharBuffer.wrap(src, off, len));
}
}
public void append(ByteBuffer from) throws IOException {
if (bb.remaining() == 0) {
appendByteBuffer(from);
} else {
transfer(from, bb);
if (from.hasRemaining() && isFull(bb)) {
flushByteBuffer();
appendByteBuffer(from);
}
}
}
public void setErrorException(Exception e) {
coyoteResponse.setErrorException(e);
}
private void appendByteArray(byte src[], int off, int len) throws IOException {
if (len == 0) {
return;
}
int limit = bb.capacity();
while (len > limit) {
realWriteBytes(ByteBuffer.wrap(src, off, limit));
len = len - limit;
off = off + limit;
}
if (len > 0) {
transfer(src, off, len, bb);
}
}
private void appendByteBuffer(ByteBuffer from) throws IOException {
if (from.remaining() == 0) {
return;
}
int limit = bb.capacity();
int fromLimit = from.limit();
while (from.remaining() > limit) {
from.limit(from.position() + limit);
realWriteBytes(from.slice());
from.position(from.limit());
from.limit(fromLimit);
}
if (from.remaining() > 0) {
transfer(from, bb);
}
}
private void flushByteBuffer() throws IOException {
realWriteBytes(bb.slice());
clear(bb);
}
private void flushCharBuffer() throws IOException {
realWriteChars(cb.slice());
clear(cb);
}
private void transfer(byte b, ByteBuffer to) {
toWriteMode(to);
to.put(b);
toReadMode(to);
}
private void transfer(char b, CharBuffer to) {
toWriteMode(to);
to.put(b);
toReadMode(to);
}
private int transfer(byte[] buf, int off, int len, ByteBuffer to) {
toWriteMode(to);
int max = Math.min(len, to.remaining());
if (max > 0) {
to.put(buf, off, max);
}
toReadMode(to);
return max;
}
private int transfer(char[] buf, int off, int len, CharBuffer to) {
toWriteMode(to);
int max = Math.min(len, to.remaining());
if (max > 0) {
to.put(buf, off, max);
}
toReadMode(to);
return max;
}
private int transfer(String s, int off, int len, CharBuffer to) {
toWriteMode(to);
int max = Math.min(len, to.remaining());
if (max > 0) {
to.put(s, off, off + max);
}
toReadMode(to);
return max;
}
private void transfer(ByteBuffer from, ByteBuffer to) {
toWriteMode(to);
int max = Math.min(from.remaining(), to.remaining());
if (max > 0) {
int fromLimit = from.limit();
from.limit(from.position() + max);
to.put(from);
from.limit(fromLimit);
}
toReadMode(to);
}
private void clear(Buffer buffer) {
buffer.rewind().limit(0);
}
private boolean isFull(Buffer buffer) {
return buffer.limit() == buffer.capacity();
}
private void toReadMode(Buffer buffer) {
buffer.limit(buffer.position()).reset();
}
private void toWriteMode(Buffer buffer) {
buffer.mark().position(buffer.limit()).limit(buffer.capacity());
}
private static class PrivilegedCreateConverter implements PrivilegedExceptionAction<C2BConverter> {
private final Charset charset;
PrivilegedCreateConverter(Charset charset) {
this.charset = charset;
}
@Override
public C2BConverter run() throws IOException {
return new C2BConverter(charset);
}
}
}