rocksdb/thrift/lib/cpp/protocol/TCompactProtocol.tcc
Dhruba Borthakur 80c663882a Create leveldb server via Thrift.
Summary:
First draft.
Unit tests pass.

Test Plan: unit tests attached

Reviewers: heyongqiang

Reviewed By: heyongqiang

Differential Revision: https://reviews.facebook.net/D3969
2012-07-07 09:42:39 -07:00

821 lines
23 KiB
C++

/*
* 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.
*/
#ifndef THRIFT_PROTOCOL_TCOMPACTPROTOCOL_TCC_
#define THRIFT_PROTOCOL_TCOMPACTPROTOCOL_TCC_ 1
#include "thrift/lib/cpp/thrift_config.h"
#include "folly/Likely.h"
#include <limits>
/*
* TCompactProtocol::i*ToZigzag depend on the fact that the right shift
* operator on a signed integer is an arithmetic (sign-extending) shift.
* If this is not the case, the current implementation will not work.
* If anyone encounters this error, we can try to figure out the best
* way to implement an arithmetic right shift on their platform.
*/
#if !defined(SIGNED_RIGHT_SHIFT_IS) || !defined(ARITHMETIC_RIGHT_SHIFT)
# error "Unable to determine the behavior of a signed right shift"
#endif
#if SIGNED_RIGHT_SHIFT_IS != ARITHMETIC_RIGHT_SHIFT
# error "TCompactProtocol currently only works if a signed right shift is arithmetic"
#endif
namespace apache { namespace thrift { namespace protocol {
namespace detail { namespace compact {
enum Types {
CT_STOP = 0x00,
CT_BOOLEAN_TRUE = 0x01,
CT_BOOLEAN_FALSE = 0x02,
CT_BYTE = 0x03,
CT_I16 = 0x04,
CT_I32 = 0x05,
CT_I64 = 0x06,
CT_DOUBLE = 0x07,
CT_BINARY = 0x08,
CT_LIST = 0x09,
CT_SET = 0x0A,
CT_MAP = 0x0B,
CT_STRUCT = 0x0C,
};
const int8_t TTypeToCType[16] = {
CT_STOP, // T_STOP
0, // unused
CT_BOOLEAN_TRUE, // T_BOOL
CT_BYTE, // T_BYTE
CT_DOUBLE, // T_DOUBLE
0, // unused
CT_I16, // T_I16
0, // unused
CT_I32, // T_I32
0, // unused
CT_I64, // T_I64
CT_BINARY, // T_STRING
CT_STRUCT, // T_STRUCT
CT_MAP, // T_MAP
CT_SET, // T_SET
CT_LIST, // T_LIST
};
}} // end detail::compact namespace
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::writeMessageBegin(
const std::string& name,
const TMessageType messageType,
const int32_t seqid) {
uint32_t wsize = 0;
wsize += writeByte(PROTOCOL_ID);
wsize += writeByte((version_ & VERSION_MASK) | (((int32_t)messageType << TYPE_SHIFT_AMOUNT) & TYPE_MASK));
wsize += writeVarint32(seqid);
wsize += writeString(name);
return wsize;
}
/**
* 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.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::writeFieldBegin(const char* name,
const TType fieldType,
const int16_t fieldId) {
if (fieldType == T_BOOL) {
booleanField_.name = name;
booleanField_.fieldType = fieldType;
booleanField_.fieldId = fieldId;
} else {
return writeFieldBeginInternal(name, fieldType, fieldId, -1);
}
return 0;
}
/**
* Write the STOP symbol so we know there are no more fields in this struct.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::writeFieldStop() {
return writeByte(T_STOP);
}
/**
* 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.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::writeStructBegin(const char* name) {
lastField_.push(lastFieldId_);
lastFieldId_ = 0;
return 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.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::writeStructEnd() {
lastFieldId_ = lastField_.top();
lastField_.pop();
return 0;
}
/**
* Write a List header.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::writeListBegin(const TType elemType,
const uint32_t size) {
return writeCollectionBegin(elemType, size);
}
/**
* Write a set header.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::writeSetBegin(const TType elemType,
const uint32_t size) {
return writeCollectionBegin(elemType, size);
}
/**
* 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.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::writeMapBegin(const TType keyType,
const TType valType,
const uint32_t size) {
uint32_t wsize = 0;
if (size == 0) {
wsize += writeByte(0);
} else {
wsize += writeVarint32(size);
wsize += writeByte(getCompactType(keyType) << 4 | getCompactType(valType));
}
return wsize;
}
/**
* 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.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::writeBool(const bool value) {
uint32_t wsize = 0;
if (booleanField_.name != NULL) {
// we haven't written the field header yet
wsize += writeFieldBeginInternal(booleanField_.name,
booleanField_.fieldType,
booleanField_.fieldId,
value ? detail::compact::CT_BOOLEAN_TRUE :
detail::compact::CT_BOOLEAN_FALSE);
booleanField_.name = NULL;
} else {
// we're not part of a field, so just write the value
wsize += writeByte(value ? detail::compact::CT_BOOLEAN_TRUE :
detail::compact::CT_BOOLEAN_FALSE);
}
return wsize;
}
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::writeByte(const int8_t byte) {
trans_->write((uint8_t*)&byte, 1);
return 1;
}
/**
* Write an i16 as a zigzag varint.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::writeI16(const int16_t i16) {
return writeVarint32(i32ToZigzag(i16));
}
/**
* Write an i32 as a zigzag varint.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::writeI32(const int32_t i32) {
return writeVarint32(i32ToZigzag(i32));
}
/**
* Write an i64 as a zigzag varint.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::writeI64(const int64_t i64) {
return writeVarint64(i64ToZigzag(i64));
}
/**
* Write a double to the wire as 8 bytes.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::writeDouble(const double dub) {
BOOST_STATIC_ASSERT(sizeof(double) == sizeof(uint64_t));
BOOST_STATIC_ASSERT(std::numeric_limits<double>::is_iec559);
uint64_t bits = bitwise_cast<uint64_t>(dub);
if (version_ >= VERSION_DOUBLE_BE) {
bits = htonll(bits);
} else {
bits = htolell(bits);
}
trans_->write((uint8_t*)&bits, 8);
return 8;
}
/**
* Write a string to the wire with a varint size preceding.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::writeString(const char* str) {
return writeString(std::string(str));
}
template <class Transport_>
template <class String_>
uint32_t TCompactProtocolT<Transport_>::writeString(const String_& str) {
return writeBinary(str);
}
template <class Transport_>
template <class String_>
uint32_t TCompactProtocolT<Transport_>::writeBinary(const String_& str) {
uint32_t ssize = str.size();
uint32_t wsize = writeVarint32(ssize) + ssize;
trans_->write((uint8_t*)str.data(), ssize);
return wsize;
}
//
// Internal Writing methods
//
/**
* 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.
*/
template <class Transport_>
int32_t TCompactProtocolT<Transport_>::writeFieldBeginInternal(
const char* name,
const TType fieldType,
const int16_t fieldId,
int8_t typeOverride) {
uint32_t wsize = 0;
// if there's a type override, use that.
int8_t typeToWrite = (typeOverride == -1 ? getCompactType(fieldType) : typeOverride);
// check if we can use delta encoding for the field id
if (fieldId > lastFieldId_ && fieldId - lastFieldId_ <= 15) {
// write them together
wsize += writeByte((fieldId - lastFieldId_) << 4 | typeToWrite);
} else {
// write them separate
wsize += writeByte(typeToWrite);
wsize += writeI16(fieldId);
}
lastFieldId_ = fieldId;
return wsize;
}
/**
* Abstract method for writing the start of lists and sets. List and sets on
* the wire differ only by the type indicator.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::writeCollectionBegin(int8_t elemType,
int32_t size) {
uint32_t wsize = 0;
if (size <= 14) {
wsize += writeByte(size << 4 | getCompactType(elemType));
} else {
wsize += writeByte(0xf0 | getCompactType(elemType));
wsize += writeVarint32(size);
}
return wsize;
}
/**
* Write an i32 as a varint. Results in 1-5 bytes on the wire.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::writeVarint32(uint32_t n) {
uint8_t buf[5];
uint32_t wsize = 0;
while (true) {
if ((n & ~0x7F) == 0) {
buf[wsize++] = (int8_t)n;
break;
} else {
buf[wsize++] = (int8_t)((n & 0x7F) | 0x80);
n >>= 7;
}
}
trans_->write(buf, wsize);
return wsize;
}
/**
* Write an i64 as a varint. Results in 1-10 bytes on the wire.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::writeVarint64(uint64_t n) {
uint8_t buf[10];
uint32_t wsize = 0;
while (true) {
if ((n & ~0x7FL) == 0) {
buf[wsize++] = (int8_t)n;
break;
} else {
buf[wsize++] = (int8_t)((n & 0x7F) | 0x80);
n >>= 7;
}
}
trans_->write(buf, wsize);
return wsize;
}
/**
* Convert l into a zigzag long. This allows negative numbers to be
* represented compactly as a varint.
*/
template <class Transport_>
uint64_t TCompactProtocolT<Transport_>::i64ToZigzag(const int64_t l) {
return (l << 1) ^ (l >> 63);
}
/**
* Convert n into a zigzag int. This allows negative numbers to be
* represented compactly as a varint.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::i32ToZigzag(const int32_t n) {
return (n << 1) ^ (n >> 31);
}
/**
* Given a TType value, find the appropriate detail::compact::Types value
*/
template <class Transport_>
int8_t TCompactProtocolT<Transport_>::getCompactType(int8_t ttype) {
return detail::compact::TTypeToCType[ttype];
}
//
// Reading Methods
//
/**
* Read a message header.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::readMessageBegin(
std::string& name,
TMessageType& messageType,
int32_t& seqid) {
uint32_t rsize = 0;
int8_t protocolId;
int8_t versionAndType;
rsize += readByte(protocolId);
if (protocolId != PROTOCOL_ID) {
throw TProtocolException(TProtocolException::BAD_VERSION, "Bad protocol identifier");
}
rsize += readByte(versionAndType);
version_ = (int8_t)(versionAndType & VERSION_MASK);
if (!(version_ <= VERSION_N && version_ >= VERSION_LOW)) {
throw TProtocolException(TProtocolException::BAD_VERSION, "Bad protocol version");
}
messageType = (TMessageType)((versionAndType >> TYPE_SHIFT_AMOUNT) & 0x03);
rsize += readVarint32(seqid);
rsize += readString(name);
return rsize;
}
/**
* Read a struct begin. There's nothing on the wire for this, but it is our
* opportunity to push a new struct begin marker on the field stack.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::readStructBegin(std::string& name) {
name = "";
lastField_.push(lastFieldId_);
lastFieldId_ = 0;
return 0;
}
/**
* Doesn't actually consume any wire data, just removes the last field for
* this struct from the field stack.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::readStructEnd() {
lastFieldId_ = lastField_.top();
lastField_.pop();
return 0;
}
/**
* Read a field header off the wire.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::readFieldBegin(std::string& name,
TType& fieldType,
int16_t& fieldId) {
uint32_t rsize = 0;
int8_t byte;
int8_t type;
rsize += readByte(byte);
type = (byte & 0x0f);
// if it's a stop, then we can return immediately, as the struct is over.
if (type == T_STOP) {
fieldType = T_STOP;
fieldId = 0;
return rsize;
}
// mask off the 4 MSB of the type header. it could contain a field id delta.
int16_t modifier = (int16_t)(((uint8_t)byte & 0xf0) >> 4);
if (modifier == 0) {
// not a delta, look ahead for the zigzag varint field id.
rsize += readI16(fieldId);
} else {
fieldId = (int16_t)(lastFieldId_ + modifier);
}
fieldType = getTType(type);
// if this happens to be a boolean field, the value is encoded in the type
if (type == detail::compact::CT_BOOLEAN_TRUE ||
type == detail::compact::CT_BOOLEAN_FALSE) {
// save the boolean value in a special instance variable.
boolValue_.hasBoolValue = true;
boolValue_.boolValue =
(type == detail::compact::CT_BOOLEAN_TRUE ? true : false);
}
// push the new field onto the field stack so we can keep the deltas going.
lastFieldId_ = fieldId;
return rsize;
}
/**
* 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.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::readMapBegin(TType& keyType,
TType& valType,
uint32_t& size) {
uint32_t rsize = 0;
int8_t kvType = 0;
int32_t msize = 0;
rsize += readVarint32(msize);
if (msize != 0)
rsize += readByte(kvType);
if (msize < 0) {
throw TProtocolException(TProtocolException::NEGATIVE_SIZE);
} else if (container_limit_ && msize > container_limit_) {
throw TProtocolException(TProtocolException::SIZE_LIMIT);
}
keyType = getTType((int8_t)((uint8_t)kvType >> 4));
valType = getTType((int8_t)((uint8_t)kvType & 0xf));
size = (uint32_t)msize;
return rsize;
}
/**
* 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.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::readListBegin(TType& elemType,
uint32_t& size) {
int8_t size_and_type;
uint32_t rsize = 0;
int32_t lsize;
rsize += readByte(size_and_type);
lsize = ((uint8_t)size_and_type >> 4) & 0x0f;
if (lsize == 15) {
rsize += readVarint32(lsize);
}
if (lsize < 0) {
throw TProtocolException(TProtocolException::NEGATIVE_SIZE);
} else if (container_limit_ && lsize > container_limit_) {
throw TProtocolException(TProtocolException::SIZE_LIMIT);
}
elemType = getTType((int8_t)(size_and_type & 0x0f));
size = (uint32_t)lsize;
return rsize;
}
/**
* 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.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::readSetBegin(TType& elemType,
uint32_t& size) {
return readListBegin(elemType, size);
}
/**
* 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.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::readBool(bool& value) {
if (boolValue_.hasBoolValue == true) {
value = boolValue_.boolValue;
boolValue_.hasBoolValue = false;
return 0;
} else {
int8_t val;
readByte(val);
value = (val == detail::compact::CT_BOOLEAN_TRUE);
return 1;
}
}
/**
* Read a single byte off the wire. Nothing interesting here.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::readByte(int8_t& byte) {
uint8_t b[1];
trans_->readAll(b, 1);
byte = *(int8_t*)b;
return 1;
}
/**
* Read an i16 from the wire as a zigzag varint.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::readI16(int16_t& i16) {
int32_t value;
uint32_t rsize = readVarint32(value);
i16 = (int16_t)zigzagToI32(value);
return rsize;
}
/**
* Read an i32 from the wire as a zigzag varint.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::readI32(int32_t& i32) {
int32_t value;
uint32_t rsize = readVarint32(value);
i32 = zigzagToI32(value);
return rsize;
}
/**
* Read an i64 from the wire as a zigzag varint.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::readI64(int64_t& i64) {
int64_t value;
uint32_t rsize = readVarint64(value);
i64 = zigzagToI64(value);
return rsize;
}
/**
* No magic here - just read a double off the wire.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::readDouble(double& dub) {
BOOST_STATIC_ASSERT(sizeof(double) == sizeof(uint64_t));
BOOST_STATIC_ASSERT(std::numeric_limits<double>::is_iec559);
union {
uint64_t bits;
uint8_t b[8];
} u;
trans_->readAll(u.b, 8);
if (version_ >= VERSION_DOUBLE_BE) {
u.bits = ntohll(u.bits);
} else {
u.bits = letohll(u.bits);
}
dub = bitwise_cast<double>(u.bits);
return 8;
}
template <class Transport_>
template <class String_>
uint32_t TCompactProtocolT<Transport_>::readString(String_& str) {
return readBinary(str);
}
/**
* Read a byte[] from the wire.
*/
template <class Transport_>
template <class String_>
uint32_t TCompactProtocolT<Transport_>::readBinary(String_& str) {
int32_t rsize = 0;
int32_t size;
rsize += readVarint32(size);
// Catch empty string case
if (size == 0) {
str = "";
return rsize;
}
// Catch error cases
if (size < 0) {
throw TProtocolException(TProtocolException::NEGATIVE_SIZE);
}
if (string_limit_ > 0 && size > string_limit_) {
throw TProtocolException(TProtocolException::SIZE_LIMIT);
}
// Use the heap here to prevent stack overflow for v. large strings
if (size > string_buf_size_ || string_buf_ == NULL) {
void* new_string_buf = std::realloc(string_buf_, (uint32_t)size);
if (new_string_buf == NULL) {
throw std::bad_alloc();
}
string_buf_ = (uint8_t*)new_string_buf;
string_buf_size_ = size;
}
trans_->readAll(string_buf_, size);
str.assign((char*)string_buf_, size);
return rsize + (uint32_t)size;
}
/**
* 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.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::readVarint32(int32_t& i32) {
int64_t val;
uint32_t rsize = readVarint64(val);
i32 = (int32_t)val;
return rsize;
}
/**
* 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.
*/
template <class Transport_>
uint32_t TCompactProtocolT<Transport_>::readVarint64(int64_t& i64) {
uint32_t rsize = 0;
uint64_t val = 0;
int shift = 0;
uint8_t buf[10]; // 64 bits / (7 bits/byte) = 10 bytes.
uint32_t buf_size = sizeof(buf);
const uint8_t* borrowed = trans_->borrow(buf, &buf_size);
// Fast path.
if (borrowed != NULL) {
while (true) {
uint8_t byte = borrowed[rsize];
rsize++;
val |= (uint64_t)(byte & 0x7f) << shift;
shift += 7;
if (!(byte & 0x80)) {
i64 = val;
trans_->consume(rsize);
return rsize;
}
// Have to check for invalid data so we don't crash.
if (UNLIKELY(rsize == sizeof(buf))) {
throw TProtocolException(TProtocolException::INVALID_DATA, "Variable-length int over 10 bytes.");
}
}
}
// Slow path.
else {
while (true) {
uint8_t byte;
rsize += trans_->readAll(&byte, 1);
val |= (uint64_t)(byte & 0x7f) << shift;
shift += 7;
if (!(byte & 0x80)) {
i64 = val;
return rsize;
}
// Might as well check for invalid data on the slow path too.
if (UNLIKELY(rsize >= sizeof(buf))) {
throw TProtocolException(TProtocolException::INVALID_DATA, "Variable-length int over 10 bytes.");
}
}
}
}
/**
* Convert from zigzag int to int.
*/
template <class Transport_>
int32_t TCompactProtocolT<Transport_>::zigzagToI32(uint32_t n) {
return (n >> 1) ^ -(n & 1);
}
/**
* Convert from zigzag long to long.
*/
template <class Transport_>
int64_t TCompactProtocolT<Transport_>::zigzagToI64(uint64_t n) {
return (n >> 1) ^ -(n & 1);
}
template <class Transport_>
TType TCompactProtocolT<Transport_>::getTType(int8_t type) {
switch (type) {
case T_STOP:
return T_STOP;
case detail::compact::CT_BOOLEAN_FALSE:
case detail::compact::CT_BOOLEAN_TRUE:
return T_BOOL;
case detail::compact::CT_BYTE:
return T_BYTE;
case detail::compact::CT_I16:
return T_I16;
case detail::compact::CT_I32:
return T_I32;
case detail::compact::CT_I64:
return T_I64;
case detail::compact::CT_DOUBLE:
return T_DOUBLE;
case detail::compact::CT_BINARY:
return T_STRING;
case detail::compact::CT_LIST:
return T_LIST;
case detail::compact::CT_SET:
return T_SET;
case detail::compact::CT_MAP:
return T_MAP;
case detail::compact::CT_STRUCT:
return T_STRUCT;
default:
throw TLibraryException("don't know what type: " + type);
}
return T_STOP;
}
}}} // apache::thrift::protocol
#endif // THRIFT_PROTOCOL_TCOMPACTPROTOCOL_TCC_