/*
* 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.thrift.protocol;
import java.io.UnsupportedEncodingException;
import java.nio.ByteBuffer;
import org.apache.thrift.ShortStack;
import org.apache.thrift.TException;
import org.apache.thrift.transport.TTransport;
/**
* TCompactProtocol2 is the Java implementation of the compact protocol specified
* in THRIFT-110. The fundamental approach to reducing the overhead of
* structures is a) use variable-length integers all over the place and b) make
* use of unused bits wherever possible. Your savings will obviously vary
* based on the specific makeup of your structs, but in general, the more
* fields, nested structures, short strings and collections, and low-value i32
* and i64 fields you have, the more benefit you'll see.
*/
public class TCompactProtocol extends TProtocol {
private final static TStruct ANONYMOUS_STRUCT = new TStruct("");
private final static TField TSTOP = new TField("", TType.STOP, (short)0);
private final static byte[] ttypeToCompactType = new byte[16];
static {
ttypeToCompactType[TType.STOP] = TType.STOP;
ttypeToCompactType[TType.BOOL] = Types.BOOLEAN_TRUE;
ttypeToCompactType[TType.BYTE] = Types.BYTE;
ttypeToCompactType[TType.I16] = Types.I16;
ttypeToCompactType[TType.I32] = Types.I32;
ttypeToCompactType[TType.I64] = Types.I64;
ttypeToCompactType[TType.DOUBLE] = Types.DOUBLE;
ttypeToCompactType[TType.STRING] = Types.BINARY;
ttypeToCompactType[TType.LIST] = Types.LIST;
ttypeToCompactType[TType.SET] = Types.SET;
ttypeToCompactType[TType.MAP] = Types.MAP;
ttypeToCompactType[TType.STRUCT] = Types.STRUCT;
}
/**
* TProtocolFactory that produces TCompactProtocols.
*/
public static class Factory implements TProtocolFactory {
private final long maxNetworkBytes_;
public Factory() {
maxNetworkBytes_ = -1;
}
public Factory(int maxNetworkBytes) {
maxNetworkBytes_ = maxNetworkBytes;
}
public TProtocol getProtocol(TTransport trans) {
return new TCompactProtocol(trans, maxNetworkBytes_);
}
}
private static final byte PROTOCOL_ID = (byte)0x82;
private static final byte VERSION = 1;
private static final byte VERSION_MASK = 0x1f; // 0001 1111
private static final byte TYPE_MASK = (byte)0xE0; // 1110 0000
private static final int TYPE_SHIFT_AMOUNT = 5;
/**
* All of the on-wire type codes.
*/
private static class Types {
public static final byte BOOLEAN_TRUE = 0x01;
public static final byte BOOLEAN_FALSE = 0x02;
public static final byte BYTE = 0x03;
public static final byte I16 = 0x04;
public static final byte I32 = 0x05;
public static final byte I64 = 0x06;
public static final byte DOUBLE = 0x07;
public static final byte BINARY = 0x08;
public static final byte LIST = 0x09;
public static final byte SET = 0x0A;
public static final byte MAP = 0x0B;
public static final byte STRUCT = 0x0C;
}
/**
* Used to keep track of the last field for the current and previous structs,
* so we can do the delta stuff.
*/
private ShortStack lastField_ = new ShortStack(15);
private short lastFieldId_ = 0;
/**
* If we encounter a boolean field begin, save the TField here so it can
* have the value incorporated.
*/
private TField booleanField_ = null;
/**
* If we read a field header, and it's a boolean field, save the boolean
* value here so that readBool can use it.
*/
private Boolean boolValue_ = null;
/**
* The maximum number of bytes to read from the network for
* variable-length fields (such as strings or binary) or -1 for
* unlimited.
*/
private final long maxNetworkBytes_;
/**
* Create a TCompactProtocol.
*
* @param transport the TTransport object to read from or write to.
* @param maxNetworkBytes the maximum number of bytes to read for
* variable-length fields.
*/
public TCompactProtocol(TTransport transport, long maxNetworkBytes) {
super(transport);
maxNetworkBytes_ = maxNetworkBytes;
}
/**
* Create a TCompactProtocol.
*
* @param transport the TTransport object to read from or write to.
*/
public TCompactProtocol(TTransport transport) {
this(transport, -1);
}
@Override
public void reset() {
lastField_.clear();
lastFieldId_ = 0;
}
//
// Public Writing methods.
//
/**
* Write a message header to the wire. Compact Protocol messages contain the
* protocol version so we can migrate forwards in the future if need be.
*/
public void writeMessageBegin(TMessage message) throws TException {
writeByteDirect(PROTOCOL_ID);
writeByteDirect((VERSION & VERSION_MASK) | ((message.type << TYPE_SHIFT_AMOUNT) & TYPE_MASK));
writeVarint32(message.seqid);
writeString(message.name);
}
/**
* Write a struct begin. This doesn't actually put anything on the wire. We
* use it as an opportunity to put special placeholder markers on the field
* stack so we can get the field id deltas correct.
*/
public void writeStructBegin(TStruct struct) throws TException {
lastField_.push(lastFieldId_);
lastFieldId_ = 0;
}
/**
* Write a struct end. This doesn't actually put anything on the wire. We use
* this as an opportunity to pop the last field from the current struct off
* of the field stack.
*/
public void writeStructEnd() throws TException {
lastFieldId_ = lastField_.pop();
}
/**
* Write a field header containing the field id and field type. If the
* difference between the current field id and the last one is small (< 15),
* then the field id will be encoded in the 4 MSB as a delta. Otherwise, the
* field id will follow the type header as a zigzag varint.
*/
public void writeFieldBegin(TField field) throws TException {
if (field.type == TType.BOOL) {
// we want to possibly include the value, so we'll wait.
booleanField_ = field;
} else {
writeFieldBeginInternal(field, (byte)-1);
}
}
/**
* The workhorse of writeFieldBegin. It has the option of doing a
* 'type override' of the type header. This is used specifically in the
* boolean field case.
*/
private void writeFieldBeginInternal(TField field, byte typeOverride) throws TException {
// short lastField = lastField_.pop();
// if there's a type override, use that.
byte typeToWrite = typeOverride == -1 ? getCompactType(field.type) : typeOverride;
// check if we can use delta encoding for the field id
if (field.id > lastFieldId_ && field.id - lastFieldId_ <= 15) {
// write them together
writeByteDirect((field.id - lastFieldId_) << 4 | typeToWrite);
} else {
// write them separate
writeByteDirect(typeToWrite);
writeI16(field.id);
}
lastFieldId_ = field.id;
// lastField_.push(field.id);
}
/**
* Write the STOP symbol so we know there are no more fields in this struct.
*/
public void writeFieldStop() throws TException {
writeByteDirect(TType.STOP);
}
/**
* Write a map header. If the map is empty, omit the key and value type
* headers, as we don't need any additional information to skip it.
*/
public void writeMapBegin(TMap map) throws TException {
if (map.size == 0) {
writeByteDirect(0);
} else {
writeVarint32(map.size);
writeByteDirect(getCompactType(map.keyType) << 4 | getCompactType(map.valueType));
}
}
/**
* Write a list header.
*/
public void writeListBegin(TList list) throws TException {
writeCollectionBegin(list.elemType, list.size);
}
/**
* Write a set header.
*/
public void writeSetBegin(TSet set) throws TException {
writeCollectionBegin(set.elemType, set.size);
}
/**
* Write a boolean value. Potentially, this could be a boolean field, in
* which case the field header info isn't written yet. If so, decide what the
* right type header is for the value and then write the field header.
* Otherwise, write a single byte.
*/
public void writeBool(boolean b) throws TException {
if (booleanField_ != null) {
// we haven't written the field header yet
writeFieldBeginInternal(booleanField_, b ? Types.BOOLEAN_TRUE : Types.BOOLEAN_FALSE);
booleanField_ = null;
} else {
// we're not part of a field, so just write the value.
writeByteDirect(b ? Types.BOOLEAN_TRUE : Types.BOOLEAN_FALSE);
}
}
/**
* Write a byte. Nothing to see here!
*/
public void writeByte(byte b) throws TException {
writeByteDirect(b);
}
/**
* Write an I16 as a zigzag varint.
*/
public void writeI16(short i16) throws TException {
writeVarint32(intToZigZag(i16));
}
/**
* Write an i32 as a zigzag varint.
*/
public void writeI32(int i32) throws TException {
writeVarint32(intToZigZag(i32));
}
/**
* Write an i64 as a zigzag varint.
*/
public void writeI64(long i64) throws TException {
writeVarint64(longToZigzag(i64));
}
/**
* Write a double to the wire as 8 bytes.
*/
public void writeDouble(double dub) throws TException {
byte[] data = new byte[]{0, 0, 0, 0, 0, 0, 0, 0};
fixedLongToBytes(Double.doubleToLongBits(dub), data, 0);
trans_.write(data);
}
/**
* Write a string to the wire with a varint size preceding.
*/
public void writeString(String str) throws TException {
try {
byte[] bytes = str.getBytes("UTF-8");
writeBinary(bytes, 0, bytes.length);
} catch (UnsupportedEncodingException e) {
throw new TException("UTF-8 not supported!");
}
}
/**
* Write a byte array, using a varint for the size.
*/
public void writeBinary(ByteBuffer bin) throws TException {
int length = bin.limit() - bin.position();
writeBinary(bin.array(), bin.position() + bin.arrayOffset(), length);
}
private void writeBinary(byte[] buf, int offset, int length) throws TException {
writeVarint32(length);
trans_.write(buf, offset, length);
}
//
// These methods are called by structs, but don't actually have any wire
// output or purpose.
//
public void writeMessageEnd() throws TException {}
public void writeMapEnd() throws TException {}
public void writeListEnd() throws TException {}
public void writeSetEnd() throws TException {}
public void writeFieldEnd() throws TException {}
//
// Internal writing methods
//
/**
* Abstract method for writing the start of lists and sets. List and sets on
* the wire differ only by the type indicator.
*/
protected void writeCollectionBegin(byte elemType, int size) throws TException {
if (size <= 14) {
writeByteDirect(size << 4 | getCompactType(elemType));
} else {
writeByteDirect(0xf0 | getCompactType(elemType));
writeVarint32(size);
}
}
/**
* Write an i32 as a varint. Results in 1-5 bytes on the wire.
* TODO: make a permanent buffer like writeVarint64?
*/
byte[] i32buf = new byte[5];
private void writeVarint32(int n) throws TException {
int idx = 0;
while (true) {
if ((n & ~0x7F) == 0) {
i32buf[idx++] = (byte)n;
// writeByteDirect((byte)n);
break;
// return;
} else {
i32buf[idx++] = (byte)((n & 0x7F) | 0x80);
// writeByteDirect((byte)((n & 0x7F) | 0x80));
n >>>= 7;
}
}
trans_.write(i32buf, 0, idx);
}
/**
* Write an i64 as a varint. Results in 1-10 bytes on the wire.
*/
byte[] varint64out = new byte[10];
private void writeVarint64(long n) throws TException {
int idx = 0;
while (true) {
if ((n & ~0x7FL) == 0) {
varint64out[idx++] = (byte)n;
break;
} else {
varint64out[idx++] = ((byte)((n & 0x7F) | 0x80));
n >>>= 7;
}
}
trans_.write(varint64out, 0, idx);
}
/**
* Convert l into a zigzag long. This allows negative numbers to be
* represented compactly as a varint.
*/
private long longToZigzag(long l) {
return (l << 1) ^ (l >> 63);
}
/**
* Convert n into a zigzag int. This allows negative numbers to be
* represented compactly as a varint.
*/
private int intToZigZag(int n) {
return (n << 1) ^ (n >> 31);
}
/**
* Convert a long into little-endian bytes in buf starting at off and going
* until off+7.
*/
private void fixedLongToBytes(long n, byte[] buf, int off) {
buf[off+0] = (byte)( n & 0xff);
buf[off+1] = (byte)((n >> 8 ) & 0xff);
buf[off+2] = (byte)((n >> 16) & 0xff);
buf[off+3] = (byte)((n >> 24) & 0xff);
buf[off+4] = (byte)((n >> 32) & 0xff);
buf[off+5] = (byte)((n >> 40) & 0xff);
buf[off+6] = (byte)((n >> 48) & 0xff);
buf[off+7] = (byte)((n >> 56) & 0xff);
}
/**
* Writes a byte without any possibility of all that field header nonsense.
* Used internally by other writing methods that know they need to write a byte.
*/
private byte[] byteDirectBuffer = new byte[1];
private void writeByteDirect(byte b) throws TException {
byteDirectBuffer[0] = b;
trans_.write(byteDirectBuffer);
}
/**
* Writes a byte without any possibility of all that field header nonsense.
*/
private void writeByteDirect(int n) throws TException {
writeByteDirect((byte)n);
}
//
// Reading methods.
//
/**
* Read a message header.
*/
public TMessage readMessageBegin() throws TException {
byte protocolId = readByte();
if (protocolId != PROTOCOL_ID) {
throw new TProtocolException("Expected protocol id " + Integer.toHexString(PROTOCOL_ID) + " but got " + Integer.toHexString(protocolId));
}
byte versionAndType = readByte();
byte version = (byte)(versionAndType & VERSION_MASK);
if (version != VERSION) {
throw new TProtocolException("Expected version " + VERSION + " but got " + version);
}
byte type = (byte)((versionAndType >> TYPE_SHIFT_AMOUNT) & 0x03);
int seqid = readVarint32();
String messageName = readString();
return new TMessage(messageName, type, seqid);
}
/**
* Read a struct begin. There's nothing on the wire for this, but it is our
* opportunity to push a new struct begin marker onto the field stack.
*/
public TStruct readStructBegin() throws TException {
lastField_.push(lastFieldId_);
lastFieldId_ = 0;
return ANONYMOUS_STRUCT;
}
/**
* Doesn't actually consume any wire data, just removes the last field for
* this struct from the field stack.
*/
public void readStructEnd() throws TException {
// consume the last field we read off the wire.
lastFieldId_ = lastField_.pop();
}
/**
* Read a field header off the wire.
*/
public TField readFieldBegin() throws TException {
byte type = readByte();
// if it's a stop, then we can return immediately, as the struct is over.
if (type == TType.STOP) {
return TSTOP;
}
short fieldId;
// mask off the 4 MSB of the type header. it could contain a field id delta.
short modifier = (short)((type & 0xf0) >> 4);
if (modifier == 0) {
// not a delta. look ahead for the zigzag varint field id.
fieldId = readI16();
} else {
// has a delta. add the delta to the last read field id.
fieldId = (short)(lastFieldId_ + modifier);
}
TField field = new TField("", getTType((byte)(type & 0x0f)), fieldId);
// if this happens to be a boolean field, the value is encoded in the type
if (isBoolType(type)) {
// save the boolean value in a special instance variable.
boolValue_ = (byte)(type & 0x0f) == Types.BOOLEAN_TRUE ? Boolean.TRUE : Boolean.FALSE;
}
// push the new field onto the field stack so we can keep the deltas going.
lastFieldId_ = field.id;
return field;
}
/**
* Read a map header off the wire. If the size is zero, skip reading the key
* and value type. This means that 0-length maps will yield TMaps without the
* "correct" types.
*/
public TMap readMapBegin() throws TException {
int size = readVarint32();
byte keyAndValueType = size == 0 ? 0 : readByte();
return new TMap(getTType((byte)(keyAndValueType >> 4)), getTType((byte)(keyAndValueType & 0xf)), size);
}
/**
* Read a list header off the wire. If the list size is 0-14, the size will
* be packed into the element type header. If it's a longer list, the 4 MSB
* of the element type header will be 0xF, and a varint will follow with the
* true size.
*/
public TList readListBegin() throws TException {
byte size_and_type = readByte();
int size = (size_and_type >> 4) & 0x0f;
if (size == 15) {
size = readVarint32();
}
byte type = getTType(size_and_type);
return new TList(type, size);
}
/**
* Read a set header off the wire. If the set size is 0-14, the size will
* be packed into the element type header. If it's a longer set, the 4 MSB
* of the element type header will be 0xF, and a varint will follow with the
* true size.
*/
public TSet readSetBegin() throws TException {
return new TSet(readListBegin());
}
/**
* Read a boolean off the wire. If this is a boolean field, the value should
* already have been read during readFieldBegin, so we'll just consume the
* pre-stored value. Otherwise, read a byte.
*/
public boolean readBool() throws TException {
if (boolValue_ != null) {
boolean result = boolValue_.booleanValue();
boolValue_ = null;
return result;
}
return readByte() == Types.BOOLEAN_TRUE;
}
byte[] byteRawBuf = new byte[1];
/**
* Read a single byte off the wire. Nothing interesting here.
*/
public byte readByte() throws TException {
byte b;
if (trans_.getBytesRemainingInBuffer() > 0) {
b = trans_.getBuffer()[trans_.getBufferPosition()];
trans_.consumeBuffer(1);
} else {
trans_.readAll(byteRawBuf, 0, 1);
b = byteRawBuf[0];
}
return b;
}
/**
* Read an i16 from the wire as a zigzag varint.
*/
public short readI16() throws TException {
return (short)zigzagToInt(readVarint32());
}
/**
* Read an i32 from the wire as a zigzag varint.
*/
public int readI32() throws TException {
return zigzagToInt(readVarint32());
}
/**
* Read an i64 from the wire as a zigzag varint.
*/
public long readI64() throws TException {
return zigzagToLong(readVarint64());
}
/**
* No magic here - just read a double off the wire.
*/
public double readDouble() throws TException {
byte[] longBits = new byte[8];
trans_.readAll(longBits, 0, 8);
return Double.longBitsToDouble(bytesToLong(longBits));
}
/**
* Reads a byte[] (via readBinary), and then UTF-8 decodes it.
*/
public String readString() throws TException {
int length = readVarint32();
checkReadLength(length);
if (length == 0) {
return "";
}
try {
if (trans_.getBytesRemainingInBuffer() >= length) {
String str = new String(trans_.getBuffer(), trans_.getBufferPosition(), length, "UTF-8");
trans_.consumeBuffer(length);
return str;
} else {
return new String(readBinary(length), "UTF-8");
}
} catch (UnsupportedEncodingException e) {
throw new TException("UTF-8 not supported!");
}
}
/**
* Read a byte[] from the wire.
*/
public ByteBuffer readBinary() throws TException {
int length = readVarint32();
checkReadLength(length);
if (length == 0) return ByteBuffer.wrap(new byte[0]);
byte[] buf = new byte[length];
trans_.readAll(buf, 0, length);
return ByteBuffer.wrap(buf);
}
/**
* Read a byte[] of a known length from the wire.
*/
private byte[] readBinary(int length) throws TException {
if (length == 0) return new byte[0];
byte[] buf = new byte[length];
trans_.readAll(buf, 0, length);
return buf;
}
private void checkReadLength(int length) throws TProtocolException {
if (length < 0) {
throw new TProtocolException("Negative length: " + length);
}
if (maxNetworkBytes_ != -1 && length > maxNetworkBytes_) {
throw new TProtocolException("Length exceeded max allowed: " + length);
}
}
//
// These methods are here for the struct to call, but don't have any wire
// encoding.
//
public void readMessageEnd() throws TException {}
public void readFieldEnd() throws TException {}
public void readMapEnd() throws TException {}
public void readListEnd() throws TException {}
public void readSetEnd() throws TException {}
//
// Internal reading methods
//
/**
* Read an i32 from the wire as a varint. The MSB of each byte is set
* if there is another byte to follow. This can read up to 5 bytes.
*/
private int readVarint32() throws TException {
int result = 0;
int shift = 0;
if (trans_.getBytesRemainingInBuffer() >= 5) {
byte[] buf = trans_.getBuffer();
int pos = trans_.getBufferPosition();
int off = 0;
while (true) {
byte b = buf[pos+off];
result |= (int) (b & 0x7f) << shift;
if ((b & 0x80) != 0x80) break;
shift += 7;
off++;
}
trans_.consumeBuffer(off+1);
} else {
while (true) {
byte b = readByte();
result |= (int) (b & 0x7f) << shift;
if ((b & 0x80) != 0x80) break;
shift += 7;
}
}
return result;
}
/**
* Read an i64 from the wire as a proper varint. The MSB of each byte is set
* if there is another byte to follow. This can read up to 10 bytes.
*/
private long readVarint64() throws TException {
int shift = 0;
long result = 0;
if (trans_.getBytesRemainingInBuffer() >= 10) {
byte[] buf = trans_.getBuffer();
int pos = trans_.getBufferPosition();
int off = 0;
while (true) {
byte b = buf[pos+off];
result |= (long) (b & 0x7f) << shift;
if ((b & 0x80) != 0x80) break;
shift += 7;
off++;
}
trans_.consumeBuffer(off+1);
} else {
while (true) {
byte b = readByte();
result |= (long) (b & 0x7f) << shift;
if ((b & 0x80) != 0x80) break;
shift +=7;
}
}
return result;
}
//
// encoding helpers
//
/**
* Convert from zigzag int to int.
*/
private int zigzagToInt(int n) {
return (n >>> 1) ^ -(n & 1);
}
/**
* Convert from zigzag long to long.
*/
private long zigzagToLong(long n) {
return (n >>> 1) ^ -(n & 1);
}
/**
* Note that it's important that the mask bytes are long literals,
* otherwise they'll default to ints, and when you shift an int left 56 bits,
* you just get a messed up int.
*/
private long bytesToLong(byte[] bytes) {
return
((bytes[7] & 0xffL) << 56) |
((bytes[6] & 0xffL) << 48) |
((bytes[5] & 0xffL) << 40) |
((bytes[4] & 0xffL) << 32) |
((bytes[3] & 0xffL) << 24) |
((bytes[2] & 0xffL) << 16) |
((bytes[1] & 0xffL) << 8) |
((bytes[0] & 0xffL));
}
//
// type testing and converting
//
private boolean isBoolType(byte b) {
int lowerNibble = b & 0x0f;
return lowerNibble == Types.BOOLEAN_TRUE || lowerNibble == Types.BOOLEAN_FALSE;
}
/**
* Given a TCompactProtocol.Types constant, convert it to its corresponding
* TType value.
*/
private byte getTType(byte type) throws TProtocolException {
switch ((byte)(type & 0x0f)) {
case TType.STOP:
return TType.STOP;
case Types.BOOLEAN_FALSE:
case Types.BOOLEAN_TRUE:
return TType.BOOL;
case Types.BYTE:
return TType.BYTE;
case Types.I16:
return TType.I16;
case Types.I32:
return TType.I32;
case Types.I64:
return TType.I64;
case Types.DOUBLE:
return TType.DOUBLE;
case Types.BINARY:
return TType.STRING;
case Types.LIST:
return TType.LIST;
case Types.SET:
return TType.SET;
case Types.MAP:
return TType.MAP;
case Types.STRUCT:
return TType.STRUCT;
default:
throw new TProtocolException("don't know what type: " + (byte)(type & 0x0f));
}
}
/**
* Given a TType value, find the appropriate TCompactProtocol.Types constant.
*/
private byte getCompactType(byte ttype) {
return ttypeToCompactType[ttype];
}
}