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rocksdb/thrift/lib/cpp/transport/TZlibTransport.h

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/*
* 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_TRANSPORT_TZLIBTRANSPORT_H_
#define _THRIFT_TRANSPORT_TZLIBTRANSPORT_H_ 1
#include <boost/lexical_cast.hpp>
#include "thrift/lib/cpp/transport/TBufferTransports.h"
#include "thrift/lib/cpp/transport/TVirtualTransport.h"
struct z_stream_s;
namespace apache { namespace thrift { namespace transport {
class TZlibTransportException : public TTransportException {
public:
TZlibTransportException(int status, const char* msg) :
TTransportException(TTransportException::INTERNAL_ERROR,
errorMessage(status, msg)),
zlib_status_(status),
zlib_msg_(msg == NULL ? "(null)" : msg) {}
virtual ~TZlibTransportException() throw() {}
int getZlibStatus() { return zlib_status_; }
std::string getZlibMessage() { return zlib_msg_; }
static std::string errorMessage(int status, const char* msg) {
std::string rv = "zlib error: ";
if (msg) {
rv += msg;
} else {
rv += "(no message)";
}
rv += " (status = ";
rv += boost::lexical_cast<std::string>(status);
rv += ")";
return rv;
}
int zlib_status_;
std::string zlib_msg_;
};
/**
* This transport uses zlib's compressed format on the "far" side.
*
* There are two kinds of TZlibTransport objects:
* - Standalone objects are used to encode self-contained chunks of data
* (like structures). They include checksums.
* - Non-standalone transports are used for RPC. They are not implemented yet.
*
* TODO(dreiss): Don't do an extra copy of the compressed data if
* the underlying transport is TBuffered or TMemory.
*
*/
class TZlibTransport : public TVirtualTransport<TZlibTransport> {
public:
/**
* @param transport The transport to read compressed data from
* and write compressed data to.
* @param urbuf_size Uncompressed buffer size for reading.
* @param crbuf_size Compressed buffer size for reading.
* @param uwbuf_size Uncompressed buffer size for writing.
* @param cwbuf_size Compressed buffer size for writing.
*
* TODO(dreiss): Write a constructor that isn't a pain.
*/
TZlibTransport(boost::shared_ptr<TTransport> transport,
int urbuf_size = DEFAULT_URBUF_SIZE,
int crbuf_size = DEFAULT_CRBUF_SIZE,
int uwbuf_size = DEFAULT_UWBUF_SIZE,
int cwbuf_size = DEFAULT_CWBUF_SIZE) :
transport_(transport),
urpos_(0),
uwpos_(0),
input_ended_(false),
output_finished_(false),
urbuf_size_(urbuf_size),
crbuf_size_(crbuf_size),
uwbuf_size_(uwbuf_size),
cwbuf_size_(cwbuf_size),
urbuf_(NULL),
crbuf_(NULL),
uwbuf_(NULL),
cwbuf_(NULL),
rstream_(NULL),
wstream_(NULL)
{
if (uwbuf_size_ < MIN_DIRECT_DEFLATE_SIZE) {
// Have to copy this into a local because of a linking issue.
int minimum = MIN_DIRECT_DEFLATE_SIZE;
throw TTransportException(
TTransportException::BAD_ARGS,
"TZLibTransport: uncompressed write buffer must be at least"
+ boost::lexical_cast<std::string>(minimum) + ".");
}
try {
urbuf_ = new uint8_t[urbuf_size];
crbuf_ = new uint8_t[crbuf_size];
uwbuf_ = new uint8_t[uwbuf_size];
cwbuf_ = new uint8_t[cwbuf_size];
// Don't call this outside of the constructor.
initZlib();
} catch (...) {
delete[] urbuf_;
delete[] crbuf_;
delete[] uwbuf_;
delete[] cwbuf_;
throw;
}
}
// Don't call this outside of the constructor.
void initZlib();
/**
* TZlibTransport destructor.
*
* Warning: Destroying a TZlibTransport object may discard any written but
* unflushed data. You must explicitly call flush() or finish() to ensure
* that data is actually written and flushed to the underlying transport.
*/
~TZlibTransport();
bool isOpen();
bool peek();
void open() {
transport_->open();
}
void close() {
transport_->close();
}
uint32_t read(uint8_t* buf, uint32_t len);
void write(const uint8_t* buf, uint32_t len);
void flush();
/**
* Finalize the zlib stream.
*
* This causes zlib to flush any pending write data and write end-of-stream
* information, including the checksum. Once finish() has been called, no
* new data can be written to the stream.
*/
void finish();
const uint8_t* borrow(uint8_t* buf, uint32_t* len);
void consume(uint32_t len);
/**
* Verify the checksum at the end of the zlib stream.
*
* This may only be called after all data has been read.
* It verifies the checksum that was written by the finish() call.
*/
void verifyChecksum();
/**
* TODO(someone_smart): Choose smart defaults.
*/
static const int DEFAULT_URBUF_SIZE = 128;
static const int DEFAULT_CRBUF_SIZE = 1024;
static const int DEFAULT_UWBUF_SIZE = 128;
static const int DEFAULT_CWBUF_SIZE = 1024;
protected:
inline void checkZlibRv(int status, const char* msg);
inline void checkZlibRvNothrow(int status, const char* msg);
inline int readAvail();
void flushToTransport(int flush);
void flushToZlib(const uint8_t* buf, int len, int flush);
bool readFromZlib();
private:
// Deprecated constructor signature.
//
// This used to be the constructor signature. If you are getting a compile
// error because you are trying to use this constructor, you need to update
// your code as follows:
// - Remove the use_for_rpc argument in the constructur.
// There is no longer any distinction between RPC and standalone zlib
// transports. (Previously, only standalone was allowed, anyway.)
// - Replace TZlibTransport::flush() calls with TZlibTransport::finish()
// in your code. Previously, flush() used to finish the zlib stream.
// Now flush() only flushes out pending data, so more writes can be
// performed after a flush(). The finish() method can be used to finalize
// the zlib stream.
//
// If we don't declare this constructor, old code written as
// TZlibTransport(trans, false) still compiles but behaves incorrectly.
// The second bool argument is converted to an integer and used as the
// urbuf_size.
TZlibTransport(boost::shared_ptr<TTransport> transport,
bool use_for_rpc,
int urbuf_size = DEFAULT_URBUF_SIZE,
int crbuf_size = DEFAULT_CRBUF_SIZE,
int uwbuf_size = DEFAULT_UWBUF_SIZE,
int cwbuf_size = DEFAULT_CWBUF_SIZE);
protected:
// Writes smaller than this are buffered up.
// Larger (or equal) writes are dumped straight to zlib.
static const int MIN_DIRECT_DEFLATE_SIZE = 32;
boost::shared_ptr<TTransport> transport_;
int urpos_;
int uwpos_;
/// True iff zlib has reached the end of the input stream.
bool input_ended_;
/// True iff we have finished the output stream.
bool output_finished_;
int urbuf_size_;
int crbuf_size_;
int uwbuf_size_;
int cwbuf_size_;
uint8_t* urbuf_;
uint8_t* crbuf_;
uint8_t* uwbuf_;
uint8_t* cwbuf_;
struct z_stream_s* rstream_;
struct z_stream_s* wstream_;
};
/**
* Wraps a transport into a zlibbed one.
*
*/
class TZlibTransportFactory : public TTransportFactory {
public:
TZlibTransportFactory() {}
virtual ~TZlibTransportFactory() {}
virtual boost::shared_ptr<TTransport> getTransport(
boost::shared_ptr<TTransport> trans) {
return boost::shared_ptr<TTransport>(new TZlibTransport(trans));
}
};
/**
* Wraps a transport into a framed, zlibbed one.
*/
class TFramedZlibTransportFactory : public TTransportFactory {
public:
TFramedZlibTransportFactory() {}
virtual ~TFramedZlibTransportFactory() {}
virtual boost::shared_ptr<TTransport> getTransport(
boost::shared_ptr<TTransport> trans) {
boost::shared_ptr<TTransport> framedTransport(new TFramedTransport(trans));
return boost::shared_ptr<TTransport>(new TZlibTransport(framedTransport));
}
};
}}} // apache::thrift::transport
#endif // #ifndef _THRIFT_TRANSPORT_TZLIBTRANSPORT_H_