io.grpc.okhttp.internal.framed.Http2 Maven / Gradle / Ivy
/*
* Copyright (C) 2013 Square, Inc.
*
* 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.
*/
/*
* Forked from OkHttp 2.5.0
*/
package io.grpc.okhttp.internal.framed;
import com.google.errorprone.annotations.FormatMethod;
import io.grpc.okhttp.internal.Protocol;
import java.io.IOException;
import java.util.List;
import java.util.Locale;
import java.util.logging.Logger;
import okio.Buffer;
import okio.BufferedSink;
import okio.BufferedSource;
import okio.ByteString;
import okio.Source;
import okio.Timeout;
import static io.grpc.okhttp.internal.framed.Http2.FrameLogger.formatHeader;
import static java.lang.String.format;
import static java.util.logging.Level.FINE;
import static okio.ByteString.EMPTY;
/**
* Read and write HTTP/2 frames.
*
* This implementation assumes we do not send an increased
* {@link io.grpc.okhttp.internal.framed.Settings#getMaxFrameSize frame size setting} to the peer. Hence, we
* expect all frames to have a max length of {@link #INITIAL_MAX_FRAME_SIZE}.
*
http://tools.ietf.org/html/draft-ietf-httpbis-http2-17
*/
public final class Http2 implements Variant {
private static final Logger logger = Logger.getLogger(FrameLogger.class.getName());
@Override public Protocol getProtocol() {
return Protocol.HTTP_2;
}
private static final ByteString CONNECTION_PREFACE
= ByteString.encodeUtf8("PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n");
/** The initial max frame size, applied independently writing to, or reading from the peer. */
static final int INITIAL_MAX_FRAME_SIZE = 0x4000; // 16384
static final byte TYPE_DATA = 0x0;
static final byte TYPE_HEADERS = 0x1;
static final byte TYPE_PRIORITY = 0x2;
static final byte TYPE_RST_STREAM = 0x3;
static final byte TYPE_SETTINGS = 0x4;
static final byte TYPE_PUSH_PROMISE = 0x5;
static final byte TYPE_PING = 0x6;
static final byte TYPE_GOAWAY = 0x7;
static final byte TYPE_WINDOW_UPDATE = 0x8;
static final byte TYPE_CONTINUATION = 0x9;
static final byte FLAG_NONE = 0x0;
static final byte FLAG_ACK = 0x1; // Used for settings and ping.
static final byte FLAG_END_STREAM = 0x1; // Used for headers and data.
static final byte FLAG_END_HEADERS = 0x4; // Used for headers and continuation.
static final byte FLAG_END_PUSH_PROMISE = 0x4;
static final byte FLAG_PADDED = 0x8; // Used for headers and data.
static final byte FLAG_PRIORITY = 0x20; // Used for headers.
static final byte FLAG_COMPRESSED = 0x20; // Used for data.
/**
* Creates a frame reader with max header table size of 4096 and data frame
* compression disabled.
*/
@Override public FrameReader newReader(BufferedSource source, boolean client) {
return new Reader(source, 4096, client);
}
@Override public io.grpc.okhttp.internal.framed.FrameWriter newWriter(BufferedSink sink, boolean client) {
return new Writer(sink, client);
}
static final class Reader implements FrameReader {
private final BufferedSource source;
private final ContinuationSource continuation;
private final boolean client;
// Visible for testing.
final Hpack.Reader hpackReader;
Reader(BufferedSource source, int headerTableSize, boolean client) {
this.source = source;
this.client = client;
this.continuation = new ContinuationSource(this.source);
this.hpackReader = new Hpack.Reader(headerTableSize, continuation);
}
@Override public void readConnectionPreface() throws IOException {
if (client) return; // Nothing to read; servers doesn't send a connection preface!
ByteString connectionPreface = source.readByteString(CONNECTION_PREFACE.size());
if (logger.isLoggable(FINE)) logger.fine(format("<< CONNECTION %s", connectionPreface.hex()));
if (!CONNECTION_PREFACE.equals(connectionPreface)) {
throw ioException("Expected a connection header but was %s", connectionPreface.utf8());
}
}
@Override public boolean nextFrame(Handler handler) throws IOException {
try {
source.require(9); // Frame header size
} catch (IOException e) {
return false; // This might be a normal socket close.
}
/* 0 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Length (24) |
* +---------------+---------------+---------------+
* | Type (8) | Flags (8) |
* +-+-+-----------+---------------+-------------------------------+
* |R| Stream Identifier (31) |
* +=+=============================================================+
* | Frame Payload (0...) ...
* +---------------------------------------------------------------+
*/
int length = readMedium(source);
if (length < 0 || length > INITIAL_MAX_FRAME_SIZE) {
throw ioException("FRAME_SIZE_ERROR: %s", length);
}
byte type = (byte) (source.readByte() & 0xff);
byte flags = (byte) (source.readByte() & 0xff);
int streamId = (source.readInt() & 0x7fffffff); // Ignore reserved bit.
if (logger.isLoggable(FINE)) logger.fine(formatHeader(true, streamId, length, type, flags));
switch (type) {
case TYPE_DATA:
readData(handler, length, flags, streamId);
break;
case TYPE_HEADERS:
readHeaders(handler, length, flags, streamId);
break;
case TYPE_PRIORITY:
readPriority(handler, length, flags, streamId);
break;
case TYPE_RST_STREAM:
readRstStream(handler, length, flags, streamId);
break;
case TYPE_SETTINGS:
readSettings(handler, length, flags, streamId);
break;
case TYPE_PUSH_PROMISE:
readPushPromise(handler, length, flags, streamId);
break;
case TYPE_PING:
readPing(handler, length, flags, streamId);
break;
case TYPE_GOAWAY:
readGoAway(handler, length, flags, streamId);
break;
case TYPE_WINDOW_UPDATE:
readWindowUpdate(handler, length, flags, streamId);
break;
default:
// Implementations MUST discard frames that have unknown or unsupported types.
source.skip(length);
}
return true;
}
private void readHeaders(Handler handler, int length, byte flags, int streamId)
throws IOException {
if (streamId == 0) throw ioException("PROTOCOL_ERROR: TYPE_HEADERS streamId == 0");
boolean endStream = (flags & FLAG_END_STREAM) != 0;
short padding = (flags & FLAG_PADDED) != 0 ? (short) (source.readByte() & 0xff) : 0;
if ((flags & FLAG_PRIORITY) != 0) {
readPriority(handler, streamId);
length -= 5; // account for above read.
}
length = lengthWithoutPadding(length, flags, padding);
List headerBlock = readHeaderBlock(length, padding, flags, streamId);
handler.headers(false, endStream, streamId, -1, headerBlock, HeadersMode.HTTP_20_HEADERS);
}
private List readHeaderBlock(int length, short padding, byte flags, int streamId)
throws IOException {
continuation.length = continuation.left = length;
continuation.padding = padding;
continuation.flags = flags;
continuation.streamId = streamId;
// TODO: Concat multi-value headers with 0x0, except COOKIE, which uses 0x3B, 0x20.
// http://tools.ietf.org/html/draft-ietf-httpbis-http2-17#section-8.1.2.5
hpackReader.readHeaders();
return hpackReader.getAndResetHeaderList();
}
private void readData(Handler handler, int paddedLength, byte flags, int streamId)
throws IOException {
// TODO: checkState open or half-closed (local) or raise STREAM_CLOSED
boolean inFinished = (flags & FLAG_END_STREAM) != 0;
boolean gzipped = (flags & FLAG_COMPRESSED) != 0;
if (gzipped) {
throw ioException("PROTOCOL_ERROR: FLAG_COMPRESSED without SETTINGS_COMPRESS_DATA");
}
short padding = (flags & FLAG_PADDED) != 0 ? (short) (source.readByte() & 0xff) : 0;
int length = lengthWithoutPadding(paddedLength, flags, padding);
// FIXME: pass padding length to handler because it should be included for flow control
handler.data(inFinished, streamId, source, length, paddedLength);
source.skip(padding);
}
private void readPriority(
Handler handler, int length, @SuppressWarnings("UnusedVariable") byte flags, int streamId)
throws IOException {
if (length != 5) throw ioException("TYPE_PRIORITY length: %d != 5", length);
if (streamId == 0) throw ioException("TYPE_PRIORITY streamId == 0");
readPriority(handler, streamId);
}
private void readPriority(Handler handler, int streamId) throws IOException {
int w1 = source.readInt();
boolean exclusive = (w1 & 0x80000000) != 0;
int streamDependency = (w1 & 0x7fffffff);
int weight = (source.readByte() & 0xff) + 1;
handler.priority(streamId, streamDependency, weight, exclusive);
}
private void readRstStream(
Handler handler, int length, @SuppressWarnings("UnusedVariable") byte flags, int streamId)
throws IOException {
if (length != 4) throw ioException("TYPE_RST_STREAM length: %d != 4", length);
if (streamId == 0) throw ioException("TYPE_RST_STREAM streamId == 0");
int errorCodeInt = source.readInt();
io.grpc.okhttp.internal.framed.ErrorCode errorCode = io.grpc.okhttp.internal.framed.ErrorCode.fromHttp2(errorCodeInt);
if (errorCode == null) {
throw ioException("TYPE_RST_STREAM unexpected error code: %d", errorCodeInt);
}
handler.rstStream(streamId, errorCode);
}
private void readSettings(Handler handler, int length, byte flags, int streamId)
throws IOException {
if (streamId != 0) throw ioException("TYPE_SETTINGS streamId != 0");
if ((flags & FLAG_ACK) != 0) {
if (length != 0) throw ioException("FRAME_SIZE_ERROR ack frame should be empty!");
handler.ackSettings();
return;
}
if (length % 6 != 0) throw ioException("TYPE_SETTINGS length %% 6 != 0: %s", length);
io.grpc.okhttp.internal.framed.Settings settings = new io.grpc.okhttp.internal.framed.Settings();
for (int i = 0; i < length; i += 6) {
short id = source.readShort();
int value = source.readInt();
switch (id) {
case 1: // SETTINGS_HEADER_TABLE_SIZE
break;
case 2: // SETTINGS_ENABLE_PUSH
if (value != 0 && value != 1) {
throw ioException("PROTOCOL_ERROR SETTINGS_ENABLE_PUSH != 0 or 1");
}
break;
case 3: // SETTINGS_MAX_CONCURRENT_STREAMS
id = 4; // Renumbered in draft 10.
break;
case 4: // SETTINGS_INITIAL_WINDOW_SIZE
id = 7; // Renumbered in draft 10.
if (value < 0) {
throw ioException("PROTOCOL_ERROR SETTINGS_INITIAL_WINDOW_SIZE > 2^31 - 1");
}
break;
case 5: // SETTINGS_MAX_FRAME_SIZE
if (value < INITIAL_MAX_FRAME_SIZE || value > 16777215) {
throw ioException("PROTOCOL_ERROR SETTINGS_MAX_FRAME_SIZE: %s", value);
}
break;
case 6: // SETTINGS_MAX_HEADER_LIST_SIZE
break; // Advisory only, so ignored.
default:
// Implementations MUST ignore any unknown or unsupported identifier.
continue;
}
settings.set(id, 0, value);
}
handler.settings(false, settings);
if (settings.getHeaderTableSize() >= 0) {
hpackReader.headerTableSizeSetting(settings.getHeaderTableSize());
}
}
private void readPushPromise(Handler handler, int length, byte flags, int streamId)
throws IOException {
if (streamId == 0) {
throw ioException("PROTOCOL_ERROR: TYPE_PUSH_PROMISE streamId == 0");
}
short padding = (flags & FLAG_PADDED) != 0 ? (short) (source.readByte() & 0xff) : 0;
int promisedStreamId = source.readInt() & 0x7fffffff;
length -= 4; // account for above read.
length = lengthWithoutPadding(length, flags, padding);
List headerBlock = readHeaderBlock(length, padding, flags, streamId);
handler.pushPromise(streamId, promisedStreamId, headerBlock);
}
private void readPing(Handler handler, int length, byte flags, int streamId)
throws IOException {
if (length != 8) throw ioException("TYPE_PING length != 8: %s", length);
if (streamId != 0) throw ioException("TYPE_PING streamId != 0");
int payload1 = source.readInt();
int payload2 = source.readInt();
boolean ack = (flags & FLAG_ACK) != 0;
handler.ping(ack, payload1, payload2);
}
private void readGoAway(
Handler handler, int length, @SuppressWarnings("UnusedVariable") byte flags, int streamId)
throws IOException {
if (length < 8) throw ioException("TYPE_GOAWAY length < 8: %s", length);
if (streamId != 0) throw ioException("TYPE_GOAWAY streamId != 0");
int lastStreamId = source.readInt();
int errorCodeInt = source.readInt();
int opaqueDataLength = length - 8;
io.grpc.okhttp.internal.framed.ErrorCode errorCode = io.grpc.okhttp.internal.framed.ErrorCode.fromHttp2(errorCodeInt);
if (errorCode == null) {
throw ioException("TYPE_GOAWAY unexpected error code: %d", errorCodeInt);
}
ByteString debugData = EMPTY;
if (opaqueDataLength > 0) { // Must read debug data in order to not corrupt the connection.
debugData = source.readByteString(opaqueDataLength);
}
handler.goAway(lastStreamId, errorCode, debugData);
}
private void readWindowUpdate(
Handler handler, int length, @SuppressWarnings("UnusedVariable") byte flags, int streamId)
throws IOException {
if (length != 4) throw ioException("TYPE_WINDOW_UPDATE length !=4: %s", length);
long increment = (source.readInt() & 0x7fffffffL);
if (increment == 0) throw ioException("windowSizeIncrement was 0");
handler.windowUpdate(streamId, increment);
}
@Override public void close() throws IOException {
source.close();
}
}
static final class Writer implements io.grpc.okhttp.internal.framed.FrameWriter {
private final BufferedSink sink;
private final boolean client;
private final Buffer hpackBuffer;
private final Hpack.Writer hpackWriter;
private int maxFrameSize;
private boolean closed;
Writer(BufferedSink sink, boolean client) {
this.sink = sink;
this.client = client;
this.hpackBuffer = new Buffer();
this.hpackWriter = new Hpack.Writer(hpackBuffer);
this.maxFrameSize = INITIAL_MAX_FRAME_SIZE;
}
@Override public synchronized void flush() throws IOException {
if (closed) throw new IOException("closed");
sink.flush();
}
@Override public synchronized void ackSettings(io.grpc.okhttp.internal.framed.Settings peerSettings) throws IOException {
if (closed) throw new IOException("closed");
this.maxFrameSize = peerSettings.getMaxFrameSize(maxFrameSize);
int length = 0;
byte type = TYPE_SETTINGS;
byte flags = FLAG_ACK;
int streamId = 0;
frameHeader(streamId, length, type, flags);
sink.flush();
}
@Override public synchronized void connectionPreface() throws IOException {
if (closed) throw new IOException("closed");
if (!client) return; // Nothing to write; servers don't send connection headers!
if (logger.isLoggable(FINE)) {
logger.fine(format(">> CONNECTION %s", CONNECTION_PREFACE.hex()));
}
sink.write(CONNECTION_PREFACE.toByteArray());
sink.flush();
}
@Override public synchronized void synStream(boolean outFinished, boolean inFinished,
int streamId, int associatedStreamId, List headerBlock)
throws IOException {
if (inFinished) throw new UnsupportedOperationException();
if (closed) throw new IOException("closed");
headers(outFinished, streamId, headerBlock);
}
@Override public synchronized void synReply(boolean outFinished, int streamId,
List headerBlock) throws IOException {
if (closed) throw new IOException("closed");
headers(outFinished, streamId, headerBlock);
}
@Override public synchronized void headers(int streamId, List headerBlock)
throws IOException {
if (closed) throw new IOException("closed");
headers(false, streamId, headerBlock);
}
@Override public synchronized void pushPromise(int streamId, int promisedStreamId,
List requestHeaders) throws IOException {
if (closed) throw new IOException("closed");
hpackWriter.writeHeaders(requestHeaders);
long byteCount = hpackBuffer.size();
int length = (int) Math.min(maxFrameSize - 4, byteCount);
byte type = TYPE_PUSH_PROMISE;
byte flags = byteCount == length ? FLAG_END_HEADERS : 0;
frameHeader(streamId, length + 4, type, flags);
sink.writeInt(promisedStreamId & 0x7fffffff);
sink.write(hpackBuffer, length);
if (byteCount > length) writeContinuationFrames(streamId, byteCount - length);
}
void headers(boolean outFinished, int streamId, List headerBlock) throws IOException {
if (closed) throw new IOException("closed");
hpackWriter.writeHeaders(headerBlock);
long byteCount = hpackBuffer.size();
int length = (int) Math.min(maxFrameSize, byteCount);
byte type = TYPE_HEADERS;
byte flags = byteCount == length ? FLAG_END_HEADERS : 0;
if (outFinished) flags |= FLAG_END_STREAM;
frameHeader(streamId, length, type, flags);
sink.write(hpackBuffer, length);
if (byteCount > length) writeContinuationFrames(streamId, byteCount - length);
}
private void writeContinuationFrames(int streamId, long byteCount) throws IOException {
while (byteCount > 0) {
int length = (int) Math.min(maxFrameSize, byteCount);
byteCount -= length;
frameHeader(streamId, length, TYPE_CONTINUATION, byteCount == 0 ? FLAG_END_HEADERS : 0);
sink.write(hpackBuffer, length);
}
}
@Override public synchronized void rstStream(int streamId, io.grpc.okhttp.internal.framed.ErrorCode errorCode)
throws IOException {
if (closed) throw new IOException("closed");
if (errorCode.httpCode == -1) throw new IllegalArgumentException();
int length = 4;
byte type = TYPE_RST_STREAM;
byte flags = FLAG_NONE;
frameHeader(streamId, length, type, flags);
sink.writeInt(errorCode.httpCode);
sink.flush();
}
@Override public int maxDataLength() {
return maxFrameSize;
}
@Override public synchronized void data(boolean outFinished, int streamId, Buffer source,
int byteCount) throws IOException {
if (closed) throw new IOException("closed");
byte flags = FLAG_NONE;
if (outFinished) flags |= FLAG_END_STREAM;
dataFrame(streamId, flags, source, byteCount);
}
void dataFrame(int streamId, byte flags, Buffer buffer, int byteCount) throws IOException {
byte type = TYPE_DATA;
frameHeader(streamId, byteCount, type, flags);
if (byteCount > 0) {
sink.write(buffer, byteCount);
}
}
@Override public synchronized void settings(io.grpc.okhttp.internal.framed.Settings settings) throws IOException {
if (closed) throw new IOException("closed");
int length = settings.size() * 6;
byte type = TYPE_SETTINGS;
byte flags = FLAG_NONE;
int streamId = 0;
frameHeader(streamId, length, type, flags);
for (int i = 0; i < io.grpc.okhttp.internal.framed.Settings.COUNT; i++) {
if (!settings.isSet(i)) continue;
int id = i;
if (id == 4) id = 3; // SETTINGS_MAX_CONCURRENT_STREAMS renumbered.
else if (id == 7) id = 4; // SETTINGS_INITIAL_WINDOW_SIZE renumbered.
sink.writeShort(id);
sink.writeInt(settings.get(i));
}
sink.flush();
}
@Override public synchronized void ping(boolean ack, int payload1, int payload2)
throws IOException {
if (closed) throw new IOException("closed");
int length = 8;
byte type = TYPE_PING;
byte flags = ack ? FLAG_ACK : FLAG_NONE;
int streamId = 0;
frameHeader(streamId, length, type, flags);
sink.writeInt(payload1);
sink.writeInt(payload2);
sink.flush();
}
@Override public synchronized void goAway(int lastGoodStreamId, io.grpc.okhttp.internal.framed.ErrorCode errorCode,
byte[] debugData) throws IOException {
if (closed) throw new IOException("closed");
if (errorCode.httpCode == -1) throw illegalArgument("errorCode.httpCode == -1");
int length = 8 + debugData.length;
byte type = TYPE_GOAWAY;
byte flags = FLAG_NONE;
int streamId = 0;
frameHeader(streamId, length, type, flags);
sink.writeInt(lastGoodStreamId);
sink.writeInt(errorCode.httpCode);
if (debugData.length > 0) {
sink.write(debugData);
}
sink.flush();
}
@Override public synchronized void windowUpdate(int streamId, long windowSizeIncrement)
throws IOException {
if (closed) throw new IOException("closed");
if (windowSizeIncrement == 0 || windowSizeIncrement > 0x7fffffffL) {
throw illegalArgument("windowSizeIncrement == 0 || windowSizeIncrement > 0x7fffffffL: %s",
windowSizeIncrement);
}
int length = 4;
byte type = TYPE_WINDOW_UPDATE;
byte flags = FLAG_NONE;
frameHeader(streamId, length, type, flags);
sink.writeInt((int) windowSizeIncrement);
sink.flush();
}
@Override public synchronized void close() throws IOException {
closed = true;
sink.close();
}
void frameHeader(int streamId, int length, byte type, byte flags) throws IOException {
if (logger.isLoggable(FINE)) logger.fine(formatHeader(false, streamId, length, type, flags));
if (length > maxFrameSize) {
throw illegalArgument("FRAME_SIZE_ERROR length > %d: %d", maxFrameSize, length);
}
if ((streamId & 0x80000000) != 0) throw illegalArgument("reserved bit set: %s", streamId);
writeMedium(sink, length);
sink.writeByte(type & 0xff);
sink.writeByte(flags & 0xff);
sink.writeInt(streamId & 0x7fffffff);
}
}
@FormatMethod
private static IllegalArgumentException illegalArgument(String message, Object... args) {
throw new IllegalArgumentException(format(Locale.US, message, args));
}
@FormatMethod
private static IOException ioException(String message, Object... args) throws IOException {
throw new IOException(format(Locale.US, message, args));
}
/**
* Decompression of the header block occurs above the framing layer. This
* class lazily reads continuation frames as they are needed by {@link
* Hpack.Reader#readHeaders()}.
*/
static final class ContinuationSource implements Source {
private final BufferedSource source;
int length;
byte flags;
int streamId;
int left;
short padding;
public ContinuationSource(BufferedSource source) {
this.source = source;
}
@Override public long read(Buffer sink, long byteCount) throws IOException {
while (left == 0) {
source.skip(padding);
padding = 0;
if ((flags & FLAG_END_HEADERS) != 0) return -1;
readContinuationHeader();
// TODO: test case for empty continuation header?
}
long read = source.read(sink, Math.min(byteCount, left));
if (read == -1) return -1;
left -= (int) read;
return read;
}
@Override public Timeout timeout() {
return source.timeout();
}
@Override public void close() throws IOException {
}
private void readContinuationHeader() throws IOException {
int previousStreamId = streamId;
length = left = readMedium(source);
byte type = (byte) (source.readByte() & 0xff);
flags = (byte) (source.readByte() & 0xff);
if (logger.isLoggable(FINE)) logger.fine(formatHeader(true, streamId, length, type, flags));
streamId = (source.readInt() & 0x7fffffff);
if (type != TYPE_CONTINUATION) throw ioException("%s != TYPE_CONTINUATION", type);
if (streamId != previousStreamId) throw ioException("TYPE_CONTINUATION streamId changed");
}
}
private static int lengthWithoutPadding(int length, byte flags, short padding)
throws IOException {
if ((flags & FLAG_PADDED) != 0) length--; // Account for reading the padding length.
if (padding > length) {
throw ioException("PROTOCOL_ERROR padding %s > remaining length %s", padding, length);
}
return (short) (length - padding);
}
/**
* Logs a human-readable representation of HTTP/2 frame headers.
*
* The format is:
*
*
* direction streamID length type flags
*
* Where direction is {@code <<} for inbound and {@code >>} for outbound.
*
* For example, the following would indicate a HEAD request sent from
* the client.
*
* {@code
* << 0x0000000f 12 HEADERS END_HEADERS|END_STREAM
* }
*
*/
static final class FrameLogger {
static String formatHeader(boolean inbound, int streamId, int length, byte type, byte flags) {
String formattedType = type < TYPES.length ? TYPES[type] : format("0x%02x", type);
String formattedFlags = formatFlags(type, flags);
return format(Locale.US, "%s 0x%08x %5d %-13s %s", inbound ? "<<" : ">>", streamId, length,
formattedType, formattedFlags);
}
/**
* Looks up valid string representing flags from the table. Invalid
* combinations are represented in binary.
*/
// Visible for testing.
static String formatFlags(byte type, byte flags) {
if (flags == 0) return "";
switch (type) { // Special case types that have 0 or 1 flag.
case TYPE_SETTINGS:
case TYPE_PING:
return flags == FLAG_ACK ? "ACK" : BINARY[flags];
case TYPE_PRIORITY:
case TYPE_RST_STREAM:
case TYPE_GOAWAY:
case TYPE_WINDOW_UPDATE:
return BINARY[flags];
}
String result = flags < FLAGS.length ? FLAGS[flags] : BINARY[flags];
// Special case types that have overlap flag values.
if (type == TYPE_PUSH_PROMISE && (flags & FLAG_END_PUSH_PROMISE) != 0) {
return result.replace("HEADERS", "PUSH_PROMISE"); // TODO: Avoid allocation.
} else if (type == TYPE_DATA && (flags & FLAG_COMPRESSED) != 0) {
return result.replace("PRIORITY", "COMPRESSED"); // TODO: Avoid allocation.
}
return result;
}
/** Lookup table for valid frame types. */
private static final String[] TYPES = new String[] {
"DATA",
"HEADERS",
"PRIORITY",
"RST_STREAM",
"SETTINGS",
"PUSH_PROMISE",
"PING",
"GOAWAY",
"WINDOW_UPDATE",
"CONTINUATION"
};
/**
* Lookup table for valid flags for DATA, HEADERS, CONTINUATION. Invalid
* combinations are represented in binary.
*/
private static final String[] FLAGS = new String[0x40]; // Highest bit flag is 0x20.
private static final String[] BINARY = new String[256];
static {
for (int i = 0; i < BINARY.length; i++) {
BINARY[i] = format("%8s", Integer.toBinaryString(i)).replace(' ', '0');
}
FLAGS[FLAG_NONE] = "";
FLAGS[FLAG_END_STREAM] = "END_STREAM";
int[] prefixFlags = new int[] {FLAG_END_STREAM};
FLAGS[FLAG_PADDED] = "PADDED";
for (int prefixFlag : prefixFlags) {
FLAGS[prefixFlag | FLAG_PADDED] = FLAGS[prefixFlag] + "|PADDED";
}
FLAGS[FLAG_END_HEADERS] = "END_HEADERS"; // Same as END_PUSH_PROMISE.
FLAGS[FLAG_PRIORITY] = "PRIORITY"; // Same as FLAG_COMPRESSED.
FLAGS[FLAG_END_HEADERS | FLAG_PRIORITY] = "END_HEADERS|PRIORITY"; // Only valid on HEADERS.
int[] frameFlags =
new int[] {FLAG_END_HEADERS, FLAG_PRIORITY, FLAG_END_HEADERS | FLAG_PRIORITY};
for (int frameFlag : frameFlags) {
for (int prefixFlag : prefixFlags) {
FLAGS[prefixFlag | frameFlag] = FLAGS[prefixFlag] + '|' + FLAGS[frameFlag];
FLAGS[prefixFlag | frameFlag | FLAG_PADDED] =
FLAGS[prefixFlag] + '|' + FLAGS[frameFlag] + "|PADDED";
}
}
for (int i = 0; i < FLAGS.length; i++) { // Fill in holes with binary representation.
if (FLAGS[i] == null) FLAGS[i] = BINARY[i];
}
}
}
private static int readMedium(BufferedSource source) throws IOException {
return (source.readByte() & 0xff) << 16
| (source.readByte() & 0xff) << 8
| (source.readByte() & 0xff);
}
private static void writeMedium(BufferedSink sink, int i) throws IOException {
sink.writeByte((i >>> 16) & 0xff);
sink.writeByte((i >>> 8) & 0xff);
sink.writeByte(i & 0xff);
}
}