Subversion Repositories SmartDukaan

/*

 * 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_TDENSEPROTOCOL_H_

#define _THRIFT_PROTOCOL_TDENSEPROTOCOL_H_ 1

#include "TBinaryProtocol.h"

namespace apache { namespace thrift { namespace protocol {

/**

 * !!!WARNING!!!

 * This class is still highly experimental.  Incompatible changes

 * WILL be made to it without notice.  DO NOT USE IT YET unless

 * you are coordinating your testing with the author.

 *

 * The dense protocol is designed to use as little space as possible.

 *

 * There are two types of dense protocol instances.  Standalone instances

 * are not used for RPC and just encoded and decode structures of

 * a predetermined type.  Non-standalone instances are used for RPC.

 * Currently, only standalone instances exist.

 *

 * To use a standalone dense protocol object, you must set the type_spec

 * property (either in the constructor, or with setTypeSpec) to the local

 * reflection TypeSpec of the structures you will write to (or read from) the

 * protocol instance.

 *

 * BEST PRACTICES:

 * - Never use optional for primitives or containers.

 * - Only use optional for structures if they are very big and very rarely set.

 * - All integers are variable-length, so you can use i64 without bloating.

 * - NEVER EVER change the struct definitions IN ANY WAY without either

 *   changing your cache keys or talking to dreiss.

 *

 * TODO(dreiss): New class write with old meta.

 *

 * We override all of TBinaryProtocol's methods.

 * We inherit so that we can can explicitly call TBPs's primitive-writing

 * methods within our versions.

 *

 */

class TDenseProtocol : public TBinaryProtocol {

 protected:

  static const int32_t VERSION_MASK = 0xffff0000;

  // VERSION_1 (0x80010000)  is taken by TBinaryProtocol.

  static const int32_t VERSION_2 = 0x80020000;

 public:

  typedef apache::thrift::reflection::local::TypeSpec TypeSpec;

  static const int FP_PREFIX_LEN;

  /**

   * @param tran       The transport to use.

   * @param type_spec  The TypeSpec of the structures using this protocol.

   */

  TDenseProtocol(boost::shared_ptr<TTransport> trans,

                 TypeSpec* type_spec = NULL) :

    TBinaryProtocol(trans),

    type_spec_(type_spec),

    standalone_(true)

  {}

  void setTypeSpec(TypeSpec* type_spec) {

    type_spec_ = type_spec;

  }

  TypeSpec* getTypeSpec() {

    return type_spec_;

  }

  /*

   * Writing functions.

   */

  virtual uint32_t writeMessageBegin(const std::string& name,

                                     const TMessageType messageType,

                                     const int32_t seqid);

  virtual uint32_t writeMessageEnd();

  virtual uint32_t writeStructBegin(const char* name);

  virtual uint32_t writeStructEnd();

  virtual uint32_t writeFieldBegin(const char* name,

                                   const TType fieldType,

                                   const int16_t fieldId);

  virtual uint32_t writeFieldEnd();

  virtual uint32_t writeFieldStop();

  virtual uint32_t writeMapBegin(const TType keyType,

                                 const TType valType,

                                 const uint32_t size);

  virtual uint32_t writeMapEnd();

  virtual uint32_t writeListBegin(const TType elemType,

                                  const uint32_t size);

  virtual uint32_t writeListEnd();

  virtual uint32_t writeSetBegin(const TType elemType,

                                 const uint32_t size);

  virtual uint32_t writeSetEnd();

  virtual uint32_t writeBool(const bool value);

  virtual uint32_t writeByte(const int8_t byte);

  virtual uint32_t writeI16(const int16_t i16);

  virtual uint32_t writeI32(const int32_t i32);

  virtual uint32_t writeI64(const int64_t i64);

  virtual uint32_t writeDouble(const double dub);

  virtual uint32_t writeString(const std::string& str);

  virtual uint32_t writeBinary(const std::string& str);

  /*

   * Helper writing functions (don't do state transitions).

   */

  inline uint32_t subWriteI32(const int32_t i32);

  inline uint32_t subWriteString(const std::string& str);

  uint32_t subWriteBool(const bool value) {

    return TBinaryProtocol::writeBool(value);

  }

  /*

   * Reading functions

   */

  uint32_t readMessageBegin(std::string& name,

                            TMessageType& messageType,

                            int32_t& seqid);

  uint32_t readMessageEnd();

  uint32_t readStructBegin(std::string& name);

  uint32_t readStructEnd();

  uint32_t readFieldBegin(std::string& name,

                          TType& fieldType,

                          int16_t& fieldId);

  uint32_t readFieldEnd();

  uint32_t readMapBegin(TType& keyType,

                        TType& valType,

                        uint32_t& size);

  uint32_t readMapEnd();

  uint32_t readListBegin(TType& elemType,

                         uint32_t& size);

  uint32_t readListEnd();

  uint32_t readSetBegin(TType& elemType,

                        uint32_t& size);

  uint32_t readSetEnd();

  uint32_t readBool(bool& value);

  uint32_t readByte(int8_t& byte);

  uint32_t readI16(int16_t& i16);

  uint32_t readI32(int32_t& i32);

  uint32_t readI64(int64_t& i64);

  uint32_t readDouble(double& dub);

  uint32_t readString(std::string& str);

  uint32_t readBinary(std::string& str);

  /*

   * Helper reading functions (don't do state transitions).

   */

  inline uint32_t subReadI32(int32_t& i32);

  inline uint32_t subReadString(std::string& str);

  uint32_t subReadBool(bool& value) {

    return TBinaryProtocol::readBool(value);

  }

 private:

  // Implementation functions, documented in the .cpp.

  inline void checkTType(const TType ttype);

  inline void stateTransition();

  // Read and write variable-length integers.

  // Uses the same technique as the MIDI file format.

  inline uint32_t vlqRead(uint64_t& vlq);

  inline uint32_t vlqWrite(uint64_t vlq);

  // Called before throwing an exception to make the object reusable.

  void resetState() {

    ts_stack_.clear();

    idx_stack_.clear();

    mkv_stack_.clear();

  }

  // TypeSpec of the top-level structure to write,

  // for standalone protocol objects.

  TypeSpec* type_spec_;

  std::vector<TypeSpec*> ts_stack_;   // TypeSpec stack.

  std::vector<int>       idx_stack_;  // InDeX stack.

  std::vector<bool>      mkv_stack_;  // Map Key/Vlue stack.

                                      // True = key, False = value.

  // True iff this is a standalone instance (no RPC).

  bool standalone_;

};

}}} // apache::thrift::protocol

#endif // #ifndef _THRIFT_PROTOCOL_TDENSEPROTOCOL_H_