/*
 Copyright (c) 2011, 2019, Oracle and/or its affiliates. All rights reserved.
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License, version 2.0,
 as published by the Free Software Foundation.

 This program is also distributed with certain software (including
 but not limited to OpenSSL) that is licensed under separate terms,
 as designated in a particular file or component or in included license
 documentation.  The authors of MySQL hereby grant you an additional
 permission to link the program and your derivative works with the
 separately licensed software that they have included with MySQL.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License, version 2.0, for more details.

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
 */
#ifndef NDBMEMCACHE_EXTERNALVALUE_H
#define NDBMEMCACHE_EXTERNALVALUE_H

#include "TableSpec.h"
#include "ExpireTime.h"
#include "ndb_pipeline.h"
#include "ndb_worker.h"


#define EXTERN_VAL_MAX_PARTS 256

class ExternalValue {

  /* friend functions */
  friend ndb_async_callback callback_ext_parts_read;
  friend ndb_async_callback callback_ext_write;
  friend worker_step        append_after_read;
  friend worker_step        delete_after_header_read;

  /* Spec encapsulates an id, length, and number of parts */
  class Spec { 
  public:
    const size_t part_size;
    Uint64 id;
    size_t length;
    int nparts;
     
    Spec(int sz) : part_size(sz), id(0), length(0), nparts(0) {}
    bool readFromHeader(Operation &);
    void setLength(int length);
  };

  /* Static class methods */
public:
  static TableSpec * createContainerRecord(const char *);
  static op_status_t do_write(workitem *);
  static op_status_t do_delete(workitem *);
  static int do_delete(memory_pool *, NdbTransaction *, QueryPlan *, Operation &);
  static op_status_t do_read_header(workitem *, ndb_async_callback *, worker_step *);
  static void append_after_read(NdbTransaction *, workitem *);
  static bool setupKey(workitem *, Operation &);

  /* Public instance methods */
  ExternalValue(workitem *, NdbTransaction *t = 0);
  ~ExternalValue();
  void worker_read_external(Operation &, NdbTransaction *);
 
private:
  /* Private member variables */
  Spec old_hdr;   /** The "old" value is the one read or deleted */
  Spec new_hdr;   /** The "new" value is the one to be updated or inserted */
  ExpireTime expire_time;
  NdbTransaction *tx;
  workitem * const wqitem;
  QueryPlan * const ext_plan;  
  memory_pool * pool;
  char * value;
  size_t value_size_in_header;
  bool do_server_cas;
  Uint64 stored_cas;
  
  /* Private methods */
  op_status_t do_update();
  op_status_t do_insert();

  void update_after_header_read();
  void insert_after_header_read();
  void affix_short(int old_length, char *old_value);
  void finalize_write();

  void append();
  void prepend();
  bool insert();
  bool update();
  bool readParts();
  bool readFinalPart();
  bool deleteParts();
  bool insertParts(char * val, size_t len, int nparts, int offset);
  bool updatePart(int id, int part, char * val, size_t len);

  bool startTransaction(Operation &);
  void readStoredCas(Operation &);

  void warnMissingParts() const;
  void build_hash_item() const;
  void setMiscColumns(Operation &) const;
  void setValueColumns(Operation &) const;
  bool shouldExternalize(size_t len) const;
  int readLongValueIntoBuffer(char *) const;
};

/* Inline Methods */

inline bool ExternalValue::shouldExternalize(size_t len) const {
  return (len > value_size_in_header);
}


#endif