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/*
* Copyright 2014 The gRPC Authors
*
* 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.grpc.internal;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
import static java.lang.Math.min;
import io.grpc.Codec;
import io.grpc.Compressor;
import io.grpc.Drainable;
import io.grpc.KnownLength;
import io.grpc.Status;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;
import javax.annotation.Nullable;
/**
* Encodes gRPC messages to be delivered via the transport layer which implements {@link
* MessageFramer.Sink}.
*/
public class MessageFramer implements Framer {
private static final int NO_MAX_OUTBOUND_MESSAGE_SIZE = -1;
/**
* Sink implemented by the transport layer to receive frames and forward them to their
* destination.
*/
public interface Sink {
/**
* Delivers a frame via the transport.
*
* @param frame a non-empty buffer to deliver or {@code null} if the framer is being
* closed and there is no data to deliver.
* @param endOfStream whether the frame is the last one for the GRPC stream
* @param flush {@code true} if more data may not be arriving soon
* @param numMessages the number of messages that this series of frames represents
*/
void deliverFrame(
@Nullable WritableBuffer frame,
boolean endOfStream,
boolean flush,
int numMessages);
}
private static final int HEADER_LENGTH = 5;
private static final byte UNCOMPRESSED = 0;
private static final byte COMPRESSED = 1;
private final Sink sink;
// effectively final. Can only be set once.
private int maxOutboundMessageSize = NO_MAX_OUTBOUND_MESSAGE_SIZE;
private WritableBuffer buffer;
private Compressor compressor = Codec.Identity.NONE;
private boolean messageCompression = true;
private final OutputStreamAdapter outputStreamAdapter = new OutputStreamAdapter();
private final byte[] headerScratch = new byte[HEADER_LENGTH];
private final WritableBufferAllocator bufferAllocator;
private final StatsTraceContext statsTraceCtx;
// transportTracer is nullable until it is integrated with client transports
private boolean closed;
// Tracing and stats-related states
private int messagesBuffered;
private int currentMessageSeqNo = -1;
private long currentMessageWireSize;
/**
* Creates a {@code MessageFramer}.
*
* @param sink the sink used to deliver frames to the transport
* @param bufferAllocator allocates buffers that the transport can commit to the wire.
*/
public MessageFramer(
Sink sink, WritableBufferAllocator bufferAllocator, StatsTraceContext statsTraceCtx) {
this.sink = checkNotNull(sink, "sink");
this.bufferAllocator = checkNotNull(bufferAllocator, "bufferAllocator");
this.statsTraceCtx = checkNotNull(statsTraceCtx, "statsTraceCtx");
}
@Override
public MessageFramer setCompressor(Compressor compressor) {
this.compressor = checkNotNull(compressor, "Can't pass an empty compressor");
return this;
}
@Override
public MessageFramer setMessageCompression(boolean enable) {
messageCompression = enable;
return this;
}
@Override
public void setMaxOutboundMessageSize(int maxSize) {
checkState(maxOutboundMessageSize == NO_MAX_OUTBOUND_MESSAGE_SIZE, "max size already set");
maxOutboundMessageSize = maxSize;
}
/**
* Writes out a payload message.
*
* @param message contains the message to be written out. It will be completely consumed.
*/
@Override
public void writePayload(InputStream message) {
verifyNotClosed();
messagesBuffered++;
currentMessageSeqNo++;
currentMessageWireSize = 0;
statsTraceCtx.outboundMessage(currentMessageSeqNo);
boolean compressed = messageCompression && compressor != Codec.Identity.NONE;
int written = -1;
int messageLength = -2;
try {
messageLength = getKnownLength(message);
if (messageLength != 0 && compressed) {
written = writeCompressed(message, messageLength);
} else {
written = writeUncompressed(message, messageLength);
}
} catch (IOException e) {
// This should not be possible, since sink#deliverFrame doesn't throw.
throw Status.INTERNAL
.withDescription("Failed to frame message")
.withCause(e)
.asRuntimeException();
} catch (RuntimeException e) {
throw Status.INTERNAL
.withDescription("Failed to frame message")
.withCause(e)
.asRuntimeException();
}
if (messageLength != -1 && written != messageLength) {
String err = String.format("Message length inaccurate %s != %s", written, messageLength);
throw Status.INTERNAL.withDescription(err).asRuntimeException();
}
statsTraceCtx.outboundUncompressedSize(written);
statsTraceCtx.outboundWireSize(currentMessageWireSize);
statsTraceCtx.outboundMessageSent(currentMessageSeqNo, currentMessageWireSize, written);
}
private int writeUncompressed(InputStream message, int messageLength) throws IOException {
if (messageLength != -1) {
currentMessageWireSize = messageLength;
return writeKnownLengthUncompressed(message, messageLength);
}
BufferChainOutputStream bufferChain = new BufferChainOutputStream();
int written = writeToOutputStream(message, bufferChain);
if (maxOutboundMessageSize >= 0 && written > maxOutboundMessageSize) {
throw Status.RESOURCE_EXHAUSTED
.withDescription(
String.format("message too large %d > %d", written , maxOutboundMessageSize))
.asRuntimeException();
}
writeBufferChain(bufferChain, false);
return written;
}
private int writeCompressed(InputStream message, int unusedMessageLength) throws IOException {
BufferChainOutputStream bufferChain = new BufferChainOutputStream();
OutputStream compressingStream = compressor.compress(bufferChain);
int written;
try {
written = writeToOutputStream(message, compressingStream);
} finally {
compressingStream.close();
}
if (maxOutboundMessageSize >= 0 && written > maxOutboundMessageSize) {
throw Status.RESOURCE_EXHAUSTED
.withDescription(
String.format("message too large %d > %d", written , maxOutboundMessageSize))
.asRuntimeException();
}
writeBufferChain(bufferChain, true);
return written;
}
private int getKnownLength(InputStream inputStream) throws IOException {
if (inputStream instanceof KnownLength || inputStream instanceof ByteArrayInputStream) {
return inputStream.available();
}
return -1;
}
/**
* Write an unserialized message with a known length, uncompressed.
*/
private int writeKnownLengthUncompressed(InputStream message, int messageLength)
throws IOException {
if (maxOutboundMessageSize >= 0 && messageLength > maxOutboundMessageSize) {
throw Status.RESOURCE_EXHAUSTED
.withDescription(
String.format("message too large %d > %d", messageLength , maxOutboundMessageSize))
.asRuntimeException();
}
ByteBuffer header = ByteBuffer.wrap(headerScratch);
header.put(UNCOMPRESSED);
header.putInt(messageLength);
// Allocate the initial buffer chunk based on frame header + payload length.
// Note that the allocator may allocate a buffer larger or smaller than this length
if (buffer == null) {
buffer = bufferAllocator.allocate(header.position() + messageLength);
}
writeRaw(headerScratch, 0, header.position());
return writeToOutputStream(message, outputStreamAdapter);
}
/**
* Write a message that has been serialized to a sequence of buffers.
*/
private void writeBufferChain(BufferChainOutputStream bufferChain, boolean compressed) {
ByteBuffer header = ByteBuffer.wrap(headerScratch);
header.put(compressed ? COMPRESSED : UNCOMPRESSED);
int messageLength = bufferChain.readableBytes();
header.putInt(messageLength);
WritableBuffer writeableHeader = bufferAllocator.allocate(HEADER_LENGTH);
writeableHeader.write(headerScratch, 0, header.position());
if (messageLength == 0) {
// the payload had 0 length so make the header the current buffer.
buffer = writeableHeader;
return;
}
// Note that we are always delivering a small message to the transport here which
// may incur transport framing overhead as it may be sent separately to the contents
// of the GRPC frame.
// The final message may not be completely written because we do not flush the last buffer.
// Do not report the last message as sent.
sink.deliverFrame(writeableHeader, false, false, messagesBuffered - 1);
messagesBuffered = 1;
// Commit all except the last buffer to the sink
List bufferList = bufferChain.bufferList;
for (int i = 0; i < bufferList.size() - 1; i++) {
sink.deliverFrame(bufferList.get(i), false, false, 0);
}
// Assign the current buffer to the last in the chain so it can be used
// for future writes or written with end-of-stream=true on close.
buffer = bufferList.get(bufferList.size() - 1);
currentMessageWireSize = messageLength;
}
private static int writeToOutputStream(InputStream message, OutputStream outputStream)
throws IOException {
if (message instanceof Drainable) {
return ((Drainable) message).drainTo(outputStream);
} else {
// This makes an unnecessary copy of the bytes when bytebuf supports array(). However, we
// expect performance-critical code to support flushTo().
long written = IoUtils.copy(message, outputStream);
checkArgument(written <= Integer.MAX_VALUE, "Message size overflow: %s", written);
return (int) written;
}
}
private void writeRaw(byte[] b, int off, int len) {
while (len > 0) {
if (buffer != null && buffer.writableBytes() == 0) {
commitToSink(false, false);
}
if (buffer == null) {
// Request a buffer allocation using the message length as a hint.
buffer = bufferAllocator.allocate(len);
}
int toWrite = min(len, buffer.writableBytes());
buffer.write(b, off, toWrite);
off += toWrite;
len -= toWrite;
}
}
/**
* Flushes any buffered data in the framer to the sink.
*/
@Override
public void flush() {
if (buffer != null && buffer.readableBytes() > 0) {
commitToSink(false, true);
}
}
/**
* Indicates whether or not this framer has been closed via a call to either
* {@link #close()} or {@link #dispose()}.
*/
@Override
public boolean isClosed() {
return closed;
}
/**
* Flushes and closes the framer and releases any buffers. After the framer is closed or
* disposed, additional calls to this method will have no affect.
*/
@Override
public void close() {
if (!isClosed()) {
closed = true;
// With the current code we don't expect readableBytes > 0 to be possible here, added
// defensively to prevent buffer leak issues if the framer code changes later.
if (buffer != null && buffer.readableBytes() == 0) {
releaseBuffer();
}
commitToSink(true, true);
}
}
/**
* Closes the framer and releases any buffers, but does not flush. After the framer is
* closed or disposed, additional calls to this method will have no affect.
*/
@Override
public void dispose() {
closed = true;
releaseBuffer();
}
private void releaseBuffer() {
if (buffer != null) {
buffer.release();
buffer = null;
}
}
private void commitToSink(boolean endOfStream, boolean flush) {
WritableBuffer buf = buffer;
buffer = null;
sink.deliverFrame(buf, endOfStream, flush, messagesBuffered);
messagesBuffered = 0;
}
private void verifyNotClosed() {
if (isClosed()) {
throw new IllegalStateException("Framer already closed");
}
}
/** OutputStream whose write()s are passed to the framer. */
private class OutputStreamAdapter extends OutputStream {
/**
* This is slow, don't call it. If you care about write overhead, use a BufferedOutputStream.
* Better yet, you can use your own single byte buffer and call
* {@link #write(byte[], int, int)}.
*/
@Override
public void write(int b) {
byte[] singleByte = new byte[]{(byte)b};
write(singleByte, 0, 1);
}
@Override
public void write(byte[] b, int off, int len) {
writeRaw(b, off, len);
}
}
/**
* Produce a collection of {@link WritableBuffer} instances from the data written to an
* {@link OutputStream}.
*/
private final class BufferChainOutputStream extends OutputStream {
private final List bufferList = new ArrayList<>();
private WritableBuffer current;
/**
* This is slow, don't call it. If you care about write overhead, use a BufferedOutputStream.
* Better yet, you can use your own single byte buffer and call
* {@link #write(byte[], int, int)}.
*/
@Override
public void write(int b) throws IOException {
if (current != null && current.writableBytes() > 0) {
current.write((byte)b);
return;
}
byte[] singleByte = new byte[]{(byte)b};
write(singleByte, 0, 1);
}
@Override
public void write(byte[] b, int off, int len) {
if (current == null) {
// Request len bytes initially from the allocator, it may give us more.
current = bufferAllocator.allocate(len);
bufferList.add(current);
}
while (len > 0) {
int canWrite = Math.min(len, current.writableBytes());
if (canWrite == 0) {
// Assume message is twice as large as previous assumption if were still not done,
// the allocator may allocate more or less than this amount.
int needed = Math.max(len, current.readableBytes() * 2);
current = bufferAllocator.allocate(needed);
bufferList.add(current);
} else {
current.write(b, off, canWrite);
off += canWrite;
len -= canWrite;
}
}
}
private int readableBytes() {
int readable = 0;
for (WritableBuffer writableBuffer : bufferList) {
readable += writableBuffer.readableBytes();
}
return readable;
}
}
}
