git.m6w6.name Git - m6w6/libmemcached/blob - libmemcached/memcached.hpp

   1 /*
   2  * Summary: C++ interface for memcached server
   3  *
   4  * Copy: See Copyright for the status of this software.
   5  *
   6  * Authors: Padraig O'Sullivan <osullivan.padraig@gmail.com>
   7  *          Patrick Galbraith <patg@patg.net>
   8  */
   9
  10 /**
  11  * @file memcached.hpp
  12  * @brief Libmemcached C++ interface
  13  */
  14
  15 #ifndef LIBMEMCACHEDPP_H
  16 #define LIBMEMCACHEDPP_H
  17
  18 #include <libmemcached/memcached.h>
  19 #include <libmemcached/exception.hpp>
  20
  21 #include <string.h>
  22
  23 #include <sstream>
  24 #include <string>
  25 #include <vector>
  26 #include <map>
  27
  28 namespace memcache
  29 {
  30
  31 /**
  32  * This is the core memcached library (if later, other objects
  33  * are needed, they will be created from this class).
  34  */
  35 class Memcache
  36 {
  37 public:
  38
  39   Memcache()
  40     :
  41       servers_list(),
  42       memc(),
  43       servers(NULL),
  44       result()
  45   {
  46     memcached_create(&memc);
  47   }
  48
  49   Memcache(const std::string &in_servers_list)
  50     :
  51       servers_list(in_servers_list),
  52       memc(),
  53       servers(NULL),
  54       result()
  55   {
  56     memcached_create(&memc);
  57     servers= memcached_servers_parse(servers_list.c_str());
  58     memcached_server_push(&memc, servers);
  59   }
  60
  61   Memcache(const std::string &hostname,
  62            unsigned int port)
  63     :
  64       servers_list(),
  65       memc(),
  66       servers(NULL),
  67       result()
  68   {
  69     memcached_create(&memc);
  70     servers_list.append(hostname);
  71     servers_list.append(":");
  72     std::ostringstream strsmt;
  73     strsmt << port;
  74     servers_list.append(strsmt.str());
  75     servers= memcached_servers_parse(servers_list.c_str());
  76     memcached_server_push(&memc, servers);
  77   }
  78
  79   Memcache(memcached_st *clone)
  80     :
  81       servers_list(),
  82       memc(),
  83       servers(NULL),
  84       result()
  85   {
  86     memcached_clone(&memc, clone);
  87   }
  88
  89   Memcache(const Memcache &rhs)
  90     :
  91       servers_list(rhs.servers_list),
  92       memc(),
  93       servers(NULL),
  94       result()
  95   {
  96     memcached_clone(&memc, const_cast<memcached_st *>(&rhs.getImpl()));
  97     servers= memcached_servers_parse(servers_list.c_str());
  98     memcached_server_push(&memc, servers);
  99   }
 100
 101   Memcache &operator=(const Memcache &rhs)
 102   {
 103     if (this != &rhs)
 104     {
 105       memcached_clone(&memc, const_cast<memcached_st *>(&rhs.getImpl()));
 106       servers= memcached_servers_parse(servers_list.c_str());
 107       memcached_server_push(&memc, servers);
 108     }
 109     return *this;
 110   }
 111
 112   ~Memcache()
 113   {
 114     memcached_free(&memc);
 115     memcached_server_list_free(servers);
 116   }
 117
 118   /**
 119    * Get the internal memcached_st *
 120    */
 121   memcached_st &getImpl()
 122   {
 123     return memc;
 124   }
 125
 126   /**
 127    * Get the internal memcached_st *
 128    */
 129   const memcached_st &getImpl() const
 130   {
 131     return memc;
 132   }
 133
 134   /**
 135    * Return an error string for the given return structure.
 136    *
 137    * @param[in] rc a memcached_return structure
 138    * @return error string corresponding to given return code in the library.
 139    */
 140   const std::string getError(memcached_return rc) const
 141   {
 142     /* first parameter to strerror is unused */
 143     return memcached_strerror(NULL, rc);
 144   }
 145
 146   /**
 147    * Return the string which contains the list of memcached servers being
 148    * used.
 149    *
 150    * @return a std::string containing the list of memcached servers
 151    */
 152   const std::string getServersList() const
 153   {
 154     return servers_list;
 155   }
 156
 157   /**
 158    * Set the list of memcached servers to use.
 159    *
 160    * @param[in] in_servers_list list of servers
 161    * @return true on success; false otherwise
 162    */
 163   bool setServers(const std::string &in_servers_list)
 164   {
 165     servers_list.assign(in_servers_list);
 166     servers= memcached_servers_parse(in_servers_list.c_str());
 167     memcached_server_push(&memc, servers);
 168     return (servers == NULL);
 169   }
 170
 171   /**
 172    * Add a server to the list of memcached servers to use.
 173    *
 174    * @param[in] server_name name of the server to add
 175    * @param[in] port port number of server to add
 176    * @return true on success; false otherwise
 177    */
 178   bool addServer(const std::string &server_name, unsigned int port)
 179   {
 180     memcached_return rc;
 181     std::ostringstream strstm;
 182     servers_list.append(",");
 183     servers_list.append(server_name);
 184     servers_list.append(":");
 185     strstm << port;
 186     servers_list.append(strstm.str());
 187     servers= memcached_server_list_append(servers,
 188                                           server_name.c_str(),
 189                                           port,
 190                                           &rc);
 191     memcached_server_push(&memc, servers);
 192     return (rc == MEMCACHED_SUCCESS);
 193   }
 194
 195   /**
 196    * Remove a server from the list of memcached servers to use.
 197    *
 198    * @param[in] server_name name of the server to remove
 199    * @param[in] port port number of server to remove
 200    * @return true on success; false otherwise
 201    */
 202   bool removeServer(const std::string &server_name, size_t port)
 203   {
 204     std::string tmp_str;
 205     std::ostringstream strstm;
 206     tmp_str.append(",");
 207     tmp_str.append(server_name);
 208     tmp_str.append(":");
 209     strstm << port;
 210     tmp_str.append(strstm.str());
 211     memcached_server_st *server= memcached_servers_parse(tmp_str.c_str());
 212     memcached_return rc= memcached_server_remove(server);
 213     return (rc == MEMCACHED_SUCCESS);
 214   }
 215
 216   /**
 217    * Fetches an individual value from the server. mget() must always
 218    * be called before using this method.
 219    *
 220    * @param[in] key key of object to fetch
 221    * @param[out] ret_val store returned object in this vector
 222    * @return a memcached return structure
 223    */
 224   memcached_return fetch(std::string &key,
 225                          std::vector<char> &ret_val)
 226   {
 227     char ret_key[MEMCACHED_MAX_KEY];
 228     size_t value_length= 0;
 229     size_t key_length= 0;
 230     memcached_return rc;
 231     uint32_t flags= 0;
 232     char *value= memcached_fetch(&memc, ret_key, &key_length,
 233                                  &value_length, &flags, &rc);
 234     if (value && ret_val.empty())
 235     {
 236       ret_val.reserve(value_length);
 237       ret_val.assign(value, value + value_length);
 238       key.assign(ret_key);
 239     }
 240     return rc;
 241   }
 242
 243   /**
 244    * Fetches an individual value from the server.
 245    *
 246    * @param[in] key key of object whose value to get
 247    * @param[out] ret_val object that is retrieved is stored in
 248    *                     this vector
 249    * @return true on success; false otherwise
 250    */
 251   bool get(const std::string &key,
 252            std::vector<char> &ret_val) throw (Error)
 253   {
 254     uint32_t flags= 0;
 255     memcached_return rc;
 256     size_t value_length= 0;
 257
 258     if (key.empty())
 259     {
 260       throw(Error("the key supplied is empty!", false));
 261     }
 262     char *value= memcached_get(&memc, key.c_str(), key.length(),
 263                                &value_length, &flags, &rc);
 264     if (value != NULL && ret_val.empty())
 265     {
 266       ret_val.reserve(value_length);
 267       ret_val.assign(value, value + value_length);
 268       return true;
 269     }
 270     return false;
 271   }
 272
 273   /**
 274    * Fetches an individual from a server which is specified by
 275    * the master_key parameter that is used for determining which
 276    * server an object was stored in if key partitioning was
 277    * used for storage.
 278    *
 279    * @param[in] master_key key that specifies server object is stored on
 280    * @param[in] key key of object whose value to get
 281    * @param[out] ret_val object that is retrieved is stored in
 282    *                     this vector
 283    * @return true on success; false otherwise
 284    */
 285   bool getByKey(const std::string &master_key,
 286                 const std::string &key,
 287                 std::vector<char> &ret_val) throw(Error)
 288   {
 289     uint32_t flags= 0;
 290     memcached_return rc;
 291     size_t value_length= 0;
 292
 293     if (master_key.empty() || key.empty())
 294     {
 295       throw(Error("the master key or key supplied is empty!", false));
 296     }
 297     char *value= memcached_get_by_key(&memc,
 298                                       master_key.c_str(), master_key.length(),
 299                                       key.c_str(), key.length(),
 300                                       &value_length, &flags, &rc);
 301     if (value)
 302     {
 303       ret_val.reserve(value_length);
 304       ret_val.assign(value, value + value_length);
 305       return true;
 306     }
 307     return false;
 308   }
 309
 310   /**
 311    * Selects multiple keys at once. This method always
 312    * works asynchronously.
 313    *
 314    * @param[in] keys vector of keys to select
 315    * @return true if all keys are found
 316    */
 317   bool mget(std::vector<std::string> &keys)
 318   {
 319     std::vector<const char *> real_keys;
 320     std::vector<size_t> key_len;
 321     /*
 322      * Construct an array which will contain the length
 323      * of each of the strings in the input vector. Also, to
 324      * interface with the memcached C API, we need to convert
 325      * the vector of std::string's to a vector of char *.
 326      */
 327     real_keys.reserve(keys.size());
 328     key_len.reserve(keys.size());
 329
 330     std::vector<std::string>::iterator it= keys.begin();
 331
 332     while (it != keys.end())
 333     {
 334       real_keys.push_back(const_cast<char *>((*it).c_str()));
 335       key_len.push_back((*it).length());
 336       ++it;
 337     }
 338
 339     /*
 340      * If the std::vector of keys is empty then we cannot
 341      * call memcached_mget as we will get undefined behavior.
 342      */
 343     if (! real_keys.empty())
 344     {
 345       memcached_return rc= memcached_mget(&memc, &real_keys[0], &key_len[0],
 346                                           real_keys.size());
 347       return (rc == MEMCACHED_SUCCESS);
 348     }
 349
 350     return false;
 351   }
 352
 353   /**
 354    * Writes an object to the server. If the object already exists, it will
 355    * overwrite the existing object. This method always returns true
 356    * when using non-blocking mode unless a network error occurs.
 357    *
 358    * @param[in] key key of object to write to server
 359    * @param[in] value value of object to write to server
 360    * @param[in] expiration time to keep the object stored in the server for
 361    * @param[in] flags flags to store with the object
 362    * @return true on succcess; false otherwise
 363    */
 364   bool set(const std::string &key,
 365            const std::vector<char> &value,
 366            time_t expiration,
 367            uint32_t flags) throw(Error)
 368   {
 369     if (key.empty() || value.empty())
 370     {
 371       throw(Error("the key or value supplied is empty!", false));
 372     }
 373     memcached_return rc= memcached_set(&memc,
 374                                        key.c_str(), key.length(),
 375                                        &value[0], value.size(),
 376                                        expiration, flags);
 377     return (rc == MEMCACHED_SUCCESS || rc == MEMCACHED_BUFFERED);
 378   }
 379
 380   /**
 381    * Writes an object to a server specified by the master_key parameter.
 382    * If the object already exists, it will overwrite the existing object.
 383    *
 384    * @param[in] master_key key that specifies server to write to
 385    * @param[in] key key of object to write to server
 386    * @param[in] value value of object to write to server
 387    * @param[in] expiration time to keep the object stored in the server for
 388    * @param[in] flags flags to store with the object
 389    * @return true on succcess; false otherwise
 390    */
 391   bool setByKey(const std::string &master_key,
 392                 const std::string &key,
 393                 const std::vector<char> &value,
 394                 time_t expiration,
 395                 uint32_t flags) throw(Error)
 396   {
 397     if (master_key.empty() ||
 398         key.empty() ||
 399         value.empty())
 400     {
 401       throw(Error("the key or value supplied is empty!", false));
 402     }
 403     memcached_return rc= memcached_set_by_key(&memc, master_key.c_str(),
 404                                               master_key.length(),
 405                                               key.c_str(), key.length(),
 406                                               &value[0], value.size(),
 407                                               expiration,
 408                                               flags);
 409     return (rc == MEMCACHED_SUCCESS);
 410   }
 411
 412   /**
 413    * Writes a list of objects to the server. Objects are specified by
 414    * 2 vectors - 1 vector of keys and 1 vector of values.
 415    *
 416    * @param[in] keys vector of keys of objects to write to server
 417    * @param[in] values vector of values of objects to write to server
 418    * @param[in] expiration time to keep the objects stored in server for
 419    * @param[in] flags flags to store with the objects
 420    * @return true on success; false otherwise
 421    */
 422   bool setAll(std::vector<std::string> &keys,
 423               std::vector< std::vector<char> *> &values,
 424               time_t expiration,
 425               uint32_t flags) throw(Error)
 426   {
 427     if (keys.size() != values.size())
 428     {
 429       throw(Error("The number of keys and values do not match!", false));
 430     }
 431     bool retval= true;
 432     std::vector<std::string>::iterator key_it= keys.begin();
 433     std::vector< std::vector<char> *>::iterator val_it= values.begin();
 434     while (key_it != keys.end())
 435     {
 436       retval= set((*key_it), *(*val_it), expiration, flags);
 437       if (retval == false)
 438       {
 439         return retval;
 440       }
 441       ++key_it;
 442       ++val_it;
 443     }
 444     return retval;
 445   }
 446
 447   /**
 448    * Writes a list of objects to the server. Objects are specified by
 449    * a map of keys to values.
 450    *
 451    * @param[in] key_value_map map of keys and values to store in server
 452    * @param[in] expiration time to keep the objects stored in server for
 453    * @param[in] flags flags to store with the objects
 454    * @return true on success; false otherwise
 455    */
 456   bool setAll(std::map<const std::string, std::vector<char> > &key_value_map,
 457               time_t expiration,
 458               uint32_t flags) throw(Error)
 459   {
 460     if (key_value_map.empty())
 461     {
 462       throw(Error("The key/values are not properly set!", false));
 463     }
 464     bool retval= true;
 465     std::map<const std::string, std::vector<char> >::iterator it=
 466       key_value_map.begin();
 467     while (it != key_value_map.end())
 468     {
 469       retval= set(it->first, it->second, expiration, flags);
 470       if (retval == false)
 471       {
 472         std::string err_buff("There was an error setting the key ");
 473         err_buff.append(it->first);
 474         throw(Error(err_buff, false));
 475       }
 476       ++it;
 477     }
 478     return true;
 479   }
 480
 481   /**
 482    * Increment the value of the object associated with the specified
 483    * key by the offset given. The resulting value is saved in the value
 484    * parameter.
 485    *
 486    * @param[in] key key of object in server whose value to increment
 487    * @param[in] offset amount to increment object's value by
 488    * @param[out] value store the result of the increment here
 489    * @return true on success; false otherwise
 490    */
 491   bool increment(const std::string &key, uint32_t offset, uint64_t *value) throw(Error)
 492   {
 493     if (key.empty())
 494     {
 495       throw(Error("the key supplied is empty!", false));
 496     }
 497     memcached_return rc= memcached_increment(&memc, key.c_str(), key.length(),
 498                                              offset, value);
 499     return (rc == MEMCACHED_SUCCESS);
 500   }
 501
 502   /**
 503    * Decrement the value of the object associated with the specified
 504    * key by the offset given. The resulting value is saved in the value
 505    * parameter.
 506    *
 507    * @param[in] key key of object in server whose value to decrement
 508    * @param[in] offset amount to increment object's value by
 509    * @param[out] value store the result of the decrement here
 510    * @return true on success; false otherwise
 511    */
 512   bool decrement(const std::string &key, uint32_t offset, uint64_t *value)
 513     throw(Error)
 514   {
 515     if (key.empty())
 516     {
 517       throw(Error("the key supplied is empty!", false));
 518     }
 519     memcached_return rc= memcached_decrement(&memc, key.c_str(),
 520                                              key.length(),
 521                                              offset, value);
 522     return (rc == MEMCACHED_SUCCESS);
 523   }
 524
 525
 526   /**
 527    * Add an object with the specified key and value to the server. This
 528    * function returns false if the object already exists on the server.
 529    *
 530    * @param[in] key key of object to add
 531    * @param[in] value of object to add
 532    * @return true on success; false otherwise
 533    */
 534   bool add(const std::string &key, const std::vector<char> &value)
 535     throw(Error)
 536   {
 537     if (key.empty() || value.empty())
 538     {
 539       throw(Error("the key or value supplied is empty!", false));
 540     }
 541     memcached_return rc= memcached_add(&memc, key.c_str(), key.length(),
 542                                        &value[0], value.size(), 0, 0);
 543     return (rc == MEMCACHED_SUCCESS);
 544   }
 545
 546   /**
 547    * Add an object with the specified key and value to the server. This
 548    * function returns false if the object already exists on the server. The
 549    * server to add the object to is specified by the master_key parameter.
 550    *
 551    * @param[in[ master_key key of server to add object to
 552    * @param[in] key key of object to add
 553    * @param[in] value of object to add
 554    * @return true on success; false otherwise
 555    */
 556   bool addByKey(const std::string &master_key,
 557                 const std::string &key,
 558                 const std::vector<char> &value) throw(Error)
 559   {
 560     if (master_key.empty() ||
 561         key.empty() ||
 562         value.empty())
 563     {
 564       throw(Error("the master key or key supplied is empty!", false));
 565     }
 566     memcached_return rc= memcached_add_by_key(&memc,
 567                                               master_key.c_str(),
 568                                               master_key.length(),
 569                                               key.c_str(),
 570                                               key.length(),
 571                                               &value[0],
 572                                               value.size(),
 573                                               0, 0);
 574     return (rc == MEMCACHED_SUCCESS);
 575   }
 576
 577   /**
 578    * Replaces an object on the server. This method only succeeds
 579    * if the object is already present on the server.
 580    *
 581    * @param[in] key key of object to replace
 582    * @param[in[ value value to replace object with
 583    * @return true on success; false otherwise
 584    */
 585   bool replace(const std::string &key, const std::vector<char> &value) throw(Error)
 586   {
 587     if (key.empty() ||
 588         value.empty())
 589     {
 590       throw(Error("the key or value supplied is empty!", false));
 591     }
 592     memcached_return rc= memcached_replace(&memc, key.c_str(), key.length(),
 593                                            &value[0], value.size(),
 594                                            0, 0);
 595     return (rc == MEMCACHED_SUCCESS);
 596   }
 597
 598   /**
 599    * Replaces an object on the server. This method only succeeds
 600    * if the object is already present on the server. The server
 601    * to replace the object on is specified by the master_key param.
 602    *
 603    * @param[in] master_key key of server to replace object on
 604    * @param[in] key key of object to replace
 605    * @param[in[ value value to replace object with
 606    * @return true on success; false otherwise
 607    */
 608   bool replaceByKey(const std::string &master_key,
 609                     const std::string &key,
 610                     const std::vector<char> &value)
 611   {
 612     if (master_key.empty() ||
 613         key.empty() ||
 614         value.empty())
 615     {
 616       throw(Error("the master key or key supplied is empty!", false));
 617     }
 618     memcached_return rc= memcached_replace_by_key(&memc,
 619                                                   master_key.c_str(),
 620                                                   master_key.length(),
 621                                                   key.c_str(),
 622                                                   key.length(),
 623                                                   &value[0],
 624                                                   value.size(),
 625                                                   0, 0);
 626     return (rc == MEMCACHED_SUCCESS);
 627   }
 628
 629   /**
 630    * Places a segment of data before the last piece of data stored.
 631    *
 632    * @param[in] key key of object whose value we will prepend data to
 633    * @param[in] value data to prepend to object's value
 634    * @return true on success; false otherwise
 635    */
 636   bool prepend(const std::string &key, const std::vector<char> &value)
 637     throw(Error)
 638   {
 639     if (key.empty() || value.empty())
 640     {
 641       throw(Error("the key or value supplied is empty!", false));
 642     }
 643     memcached_return rc= memcached_prepend(&memc, key.c_str(), key.length(),
 644                                            &value[0], value.size(), 0, 0);
 645     return (rc == MEMCACHED_SUCCESS);
 646   }
 647
 648   /**
 649    * Places a segment of data before the last piece of data stored. The
 650    * server on which the object where we will be prepending data is stored
 651    * on is specified by the master_key parameter.
 652    *
 653    * @param[in] master_key key of server where object is stored
 654    * @param[in] key key of object whose value we will prepend data to
 655    * @param[in] value data to prepend to object's value
 656    * @return true on success; false otherwise
 657    */
 658   bool prependByKey(const std::string &master_key,
 659                     const std::string &key,
 660                     const std::vector<char> &value)
 661       throw(Error)
 662   {
 663     if (master_key.empty() ||
 664         key.empty() ||
 665         value.empty())
 666     {
 667       throw(Error("the master key or key supplied is empty!", false));
 668     }
 669     memcached_return rc= memcached_prepend_by_key(&memc,
 670                                                   master_key.c_str(),
 671                                                   master_key.length(),
 672                                                   key.c_str(),
 673                                                   key.length(),
 674                                                   &value[0],
 675                                                   value.size(),
 676                                                   0,
 677                                                   0);
 678     return (rc == MEMCACHED_SUCCESS);
 679   }
 680
 681   /**
 682    * Places a segment of data at the end of the last piece of data stored.
 683    *
 684    * @param[in] key key of object whose value we will append data to
 685    * @param[in] value data to append to object's value
 686    * @return true on success; false otherwise
 687    */
 688   bool append(const std::string &key, const std::vector<char> &value)
 689     throw(Error)
 690   {
 691     if (key.empty() || value.empty())
 692     {
 693       throw(Error("the key or value supplied is empty!", false));
 694     }
 695     memcached_return rc= memcached_append(&memc,
 696                                           key.c_str(),
 697                                           key.length(),
 698                                           &value[0],
 699                                           value.size(),
 700                                           0, 0);
 701     return (rc == MEMCACHED_SUCCESS);
 702   }
 703
 704   /**
 705    * Places a segment of data at the end of the last piece of data stored. The
 706    * server on which the object where we will be appending data is stored
 707    * on is specified by the master_key parameter.
 708    *
 709    * @param[in] master_key key of server where object is stored
 710    * @param[in] key key of object whose value we will append data to
 711    * @param[in] value data to append to object's value
 712    * @return true on success; false otherwise
 713    */
 714   bool appendByKey(const std::string &master_key,
 715                    const std::string &key,
 716                    const std::vector<char> &value)
 717     throw(Error)
 718   {
 719     if (master_key.empty() ||
 720         key.empty() ||
 721         value.empty())
 722     {
 723       throw(Error("the master key or key supplied is empty!", false));
 724     }
 725     memcached_return rc= memcached_append_by_key(&memc,
 726                                                  master_key.c_str(),
 727                                                  master_key.length(),
 728                                                  key.c_str(),
 729                                                  key.length(),
 730                                                  &value[0],
 731                                                  value.size(),
 732                                                  0, 0);
 733     return (rc == MEMCACHED_SUCCESS);
 734   }
 735
 736   /**
 737    * Overwrite data in the server as long as the cas_arg value
 738    * is still the same in the server.
 739    *
 740    * @param[in] key key of object in server
 741    * @param[in] value value to store for object in server
 742    * @param[in] cas_arg "cas" value
 743    */
 744   bool cas(const std::string &key,
 745            const std::vector<char> &value,
 746            uint64_t cas_arg) throw(Error)
 747   {
 748     if (key.empty() || value.empty())
 749     {
 750       throw(Error("the key or value supplied is empty!", false));
 751     }
 752     memcached_return rc= memcached_cas(&memc, key.c_str(), key.length(),
 753                                        &value[0], value.size(),
 754                                        0, 0, cas_arg);
 755     return (rc == MEMCACHED_SUCCESS);
 756   }
 757
 758   /**
 759    * Overwrite data in the server as long as the cas_arg value
 760    * is still the same in the server. The server to use is
 761    * specified by the master_key parameter.
 762    *
 763    * @param[in] master_key specifies server to operate on
 764    * @param[in] key key of object in server
 765    * @param[in] value value to store for object in server
 766    * @param[in] cas_arg "cas" value
 767    */
 768   bool casByKey(const std::string &master_key,
 769                 const std::string &key,
 770                 const std::vector<char> &value,
 771                 uint64_t cas_arg) throw(Error)
 772   {
 773     if (master_key.empty() ||
 774         key.empty() ||
 775         value.empty())
 776     {
 777       throw(Error("the master key, key or value supplied is empty!", false));
 778     }
 779     memcached_return rc= memcached_cas_by_key(&memc,
 780                                               master_key.c_str(),
 781                                               master_key.length(),
 782                                               key.c_str(),
 783                                               key.length(),
 784                                               &value[0],
 785                                               value.size(),
 786                                               0, 0, cas_arg);
 787     return (rc == MEMCACHED_SUCCESS);
 788   }
 789
 790   /**
 791    * Delete an object from the server specified by the key given.
 792    *
 793    * @param[in] key key of object to delete
 794    * @return true on success; false otherwise
 795    */
 796   bool remove(const std::string &key) throw(Error)
 797   {
 798     if (key.empty())
 799     {
 800       throw(Error("the key supplied is empty!", false));
 801     }
 802     memcached_return rc= memcached_delete(&memc, key.c_str(), key.length(), 0);
 803     return (rc == MEMCACHED_SUCCESS);
 804   }
 805
 806   /**
 807    * Delete an object from the server specified by the key given.
 808    *
 809    * @param[in] key key of object to delete
 810    * @param[in] expiration time to delete the object after
 811    * @return true on success; false otherwise
 812    */
 813   bool remove(const std::string &key,
 814               time_t expiration) throw(Error)
 815   {
 816     if (key.empty())
 817     {
 818       throw(Error("the key supplied is empty!", false));
 819     }
 820     memcached_return rc= memcached_delete(&memc,
 821                                           key.c_str(),
 822                                           key.length(),
 823                                           expiration);
 824     return (rc == MEMCACHED_SUCCESS);
 825   }
 826
 827   /**
 828    * Delete an object from the server specified by the key given.
 829    *
 830    * @param[in] master_key specifies server to remove object from
 831    * @param[in] key key of object to delete
 832    * @return true on success; false otherwise
 833    */
 834   bool removeByKey(const std::string &master_key,
 835                    const std::string &key) throw(Error)
 836   {
 837     if (master_key.empty() || key.empty())
 838     {
 839       throw(Error("the master key or key supplied is empty!", false));
 840     }
 841     memcached_return rc= memcached_delete_by_key(&memc,
 842                                                  master_key.c_str(),
 843                                                  master_key.length(),
 844                                                  key.c_str(),
 845                                                  key.length(),
 846                                                  0);
 847     return (rc == MEMCACHED_SUCCESS);
 848   }
 849
 850   /**
 851    * Delete an object from the server specified by the key given.
 852    *
 853    * @param[in] master_key specifies server to remove object from
 854    * @param[in] key key of object to delete
 855    * @param[in] expiration time to delete the object after
 856    * @return true on success; false otherwise
 857    */
 858   bool removeByKey(const std::string &master_key,
 859                    const std::string &key,
 860                    time_t expiration) throw(Error)
 861   {
 862     if (master_key.empty() || key.empty())
 863     {
 864       throw(Error("the master key or key supplied is empty!", false));
 865     }
 866     memcached_return rc= memcached_delete_by_key(&memc,
 867                                                  master_key.c_str(),
 868                                                  master_key.length(),
 869                                                  key.c_str(),
 870                                                  key.length(),
 871                                                  expiration);
 872     return (rc == MEMCACHED_SUCCESS);
 873   }
 874
 875   /**
 876    * Wipe the contents of memcached servers.
 877    *
 878    * @param[in] expiration time to wait until wiping contents of
 879    *                       memcached servers
 880    * @return true on success; false otherwise
 881    */
 882   bool flush(time_t expiration)
 883   {
 884     memcached_return rc= memcached_flush(&memc, expiration);
 885     return (rc == MEMCACHED_SUCCESS);
 886   }
 887
 888   /**
 889    * Callback function for result sets. It passes the result
 890    * sets to the list of functions provided.
 891    *
 892    * @param[in] callback list of callback functions
 893    * @param[in] context pointer to memory reference that is
 894    *                    supplied to the calling function
 895    * @param[in] num_of_callbacks number of callback functions
 896    * @return true on success; false otherwise
 897    */
 898   bool fetchExecute(memcached_execute_function *callback,
 899                     void *context,
 900                     unsigned int num_of_callbacks)
 901   {
 902     memcached_return rc= memcached_fetch_execute(&memc,
 903                                                  callback,
 904                                                  context,
 905                                                  num_of_callbacks);
 906     return (rc == MEMCACHED_SUCCESS);
 907   }
 908
 909   /**
 910    * Get the library version string.
 911    * @return std::string containing a copy of the library version string.
 912    */
 913   const std::string libVersion() const
 914   {
 915     const char *ver= memcached_lib_version();
 916     const std::string version(ver);
 917     return version;
 918   }
 919
 920 private:
 921
 922   std::string servers_list;
 923   memcached_st memc;
 924   memcached_server_st *servers;
 925   memcached_result_st result;
 926 };
 927
 928 }
 929
 930 #endif /* LIBMEMCACHEDPP_H */