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       result()
  44   {
  45     memcached_create(&memc);
  46   }
  47
  48   Memcache(const std::string &in_servers_list)
  49     :
  50       servers_list(in_servers_list),
  51       memc(),
  52       result()
  53   {
  54     memcached_create(&memc);
  55     init();
  56   }
  57
  58   Memcache(const std::string &hostname,
  59            in_port_t port)
  60     :
  61       servers_list(),
  62       memc(),
  63       result()
  64   {
  65     memcached_create(&memc);
  66
  67     servers_list.append(hostname);
  68     servers_list.append(":");
  69     std::ostringstream strsmt;
  70     strsmt << port;
  71     servers_list.append(strsmt.str());
  72
  73     init();
  74   }
  75
  76   Memcache(memcached_st *clone)
  77     :
  78       servers_list(),
  79       memc(),
  80       result()
  81   {
  82     memcached_clone(&memc, clone);
  83   }
  84
  85   Memcache(const Memcache &rhs)
  86     :
  87       servers_list(rhs.servers_list),
  88       memc(),
  89       result()
  90   {
  91     memcached_clone(&memc, const_cast<memcached_st *>(&rhs.getImpl()));
  92     init();
  93   }
  94
  95   Memcache &operator=(const Memcache &rhs)
  96   {
  97     if (this != &rhs)
  98     {
  99       memcached_clone(&memc, const_cast<memcached_st *>(&rhs.getImpl()));
 100       init();
 101     }
 102
 103     return *this;
 104   }
 105
 106   ~Memcache()
 107   {
 108     memcached_free(&memc);
 109   }
 110
 111   void init()
 112   {
 113     memcached_server_st *servers;
 114     servers= memcached_servers_parse(servers_list.c_str());
 115     memcached_server_push(&memc, servers);
 116     memcached_server_free(servers);
 117   }
 118
 119   /**
 120    * Get the internal memcached_st *
 121    */
 122   memcached_st &getImpl()
 123   {
 124     return memc;
 125   }
 126
 127   /**
 128    * Get the internal memcached_st *
 129    */
 130   const memcached_st &getImpl() const
 131   {
 132     return memc;
 133   }
 134
 135   /**
 136    * Return an error string for the given return structure.
 137    *
 138    * @param[in] rc a memcached_return_t structure
 139    * @return error string corresponding to given return code in the library.
 140    */
 141   const std::string getError(memcached_return_t rc) const
 142   {
 143     /* first parameter to strerror is unused */
 144     return memcached_strerror(NULL, rc);
 145   }
 146
 147
 148   bool setBehavior(memcached_behavior_t flag, uint64_t data)
 149   {
 150     memcached_return_t rc;
 151     rc= memcached_behavior_set(&memc, flag, data);
 152     return (rc == MEMCACHED_SUCCESS);
 153   }
 154
 155   uint64_t getBehavior(memcached_behavior_t flag) {
 156     return memcached_behavior_get(&memc, flag);
 157   }
 158
 159   /**
 160    * Return the string which contains the list of memcached servers being
 161    * used.
 162    *
 163    * @return a std::string containing the list of memcached servers
 164    */
 165   const std::string getServersList() const
 166   {
 167     return servers_list;
 168   }
 169
 170   /**
 171    * Set the list of memcached servers to use.
 172    *
 173    * @param[in] in_servers_list list of servers
 174    * @return true on success; false otherwise
 175    */
 176   bool setServers(const std::string &in_servers_list)
 177   {
 178     servers_list.assign(in_servers_list);
 179     init();
 180
 181     return (memcached_server_count(&memc));
 182   }
 183
 184   /**
 185    * Add a server to the list of memcached servers to use.
 186    *
 187    * @param[in] server_name name of the server to add
 188    * @param[in] port port number of server to add
 189    * @return true on success; false otherwise
 190    */
 191   bool addServer(const std::string &server_name, in_port_t port)
 192   {
 193     memcached_return_t rc;
 194
 195     rc= memcached_server_add(&memc, server_name.c_str(), port);
 196
 197     return (rc == MEMCACHED_SUCCESS);
 198   }
 199
 200   /**
 201    * Remove a server from the list of memcached servers to use.
 202    *
 203    * @param[in] server_name name of the server to remove
 204    * @param[in] port port number of server to remove
 205    * @return true on success; false otherwise
 206    */
 207   bool removeServer(const std::string &server_name, in_port_t port)
 208   {
 209     std::string tmp_str;
 210     std::ostringstream strstm;
 211     tmp_str.append(",");
 212     tmp_str.append(server_name);
 213     tmp_str.append(":");
 214     strstm << port;
 215     tmp_str.append(strstm.str());
 216
 217     //memcached_return_t rc= memcached_server_remove(server);
 218
 219     return false;
 220   }
 221
 222   /**
 223    * Fetches an individual value from the server. mget() must always
 224    * be called before using this method.
 225    *
 226    * @param[in] key key of object to fetch
 227    * @param[out] ret_val store returned object in this vector
 228    * @return a memcached return structure
 229    */
 230   memcached_return_t fetch(std::string &key,
 231                          std::vector<char> &ret_val)
 232   {
 233     char ret_key[MEMCACHED_MAX_KEY];
 234     size_t value_length= 0;
 235     size_t key_length= 0;
 236     memcached_return_t rc;
 237     uint32_t flags= 0;
 238     char *value= memcached_fetch(&memc, ret_key, &key_length,
 239                                  &value_length, &flags, &rc);
 240     if (value && ret_val.empty())
 241     {
 242       ret_val.reserve(value_length);
 243       ret_val.assign(value, value + value_length);
 244       key.assign(ret_key, key_length);
 245       free(value);
 246     }
 247     else if (value)
 248     {
 249       free(value);
 250     }
 251
 252     return rc;
 253   }
 254
 255   /**
 256    * Fetches an individual value from the server.
 257    *
 258    * @param[in] key key of object whose value to get
 259    * @param[out] ret_val object that is retrieved is stored in
 260    *                     this vector
 261    * @return true on success; false otherwise
 262    */
 263   bool get(const std::string &key,
 264            std::vector<char> &ret_val) throw (Error)
 265   {
 266     uint32_t flags= 0;
 267     memcached_return_t rc;
 268     size_t value_length= 0;
 269
 270     if (key.empty())
 271     {
 272       throw(Error("the key supplied is empty!", false));
 273     }
 274     char *value= memcached_get(&memc, key.c_str(), key.length(),
 275                                &value_length, &flags, &rc);
 276     if (value != NULL && ret_val.empty())
 277     {
 278       ret_val.reserve(value_length);
 279       ret_val.assign(value, value + value_length);
 280       free(value);
 281       return true;
 282     }
 283     return false;
 284   }
 285
 286   /**
 287    * Fetches an individual from a server which is specified by
 288    * the master_key parameter that is used for determining which
 289    * server an object was stored in if key partitioning was
 290    * used for storage.
 291    *
 292    * @param[in] master_key key that specifies server object is stored on
 293    * @param[in] key key of object whose value to get
 294    * @param[out] ret_val object that is retrieved is stored in
 295    *                     this vector
 296    * @return true on success; false otherwise
 297    */
 298   bool getByKey(const std::string &master_key,
 299                 const std::string &key,
 300                 std::vector<char> &ret_val) throw(Error)
 301   {
 302     uint32_t flags= 0;
 303     memcached_return_t rc;
 304     size_t value_length= 0;
 305
 306     if (master_key.empty() || key.empty())
 307     {
 308       throw(Error("the master key or key supplied is empty!", false));
 309     }
 310     char *value= memcached_get_by_key(&memc,
 311                                       master_key.c_str(), master_key.length(),
 312                                       key.c_str(), key.length(),
 313                                       &value_length, &flags, &rc);
 314     if (value)
 315     {
 316       ret_val.reserve(value_length);
 317       ret_val.assign(value, value + value_length);
 318       free(value);
 319       return true;
 320     }
 321     return false;
 322   }
 323
 324   /**
 325    * Selects multiple keys at once. This method always
 326    * works asynchronously.
 327    *
 328    * @param[in] keys vector of keys to select
 329    * @return true if all keys are found
 330    */
 331   bool mget(std::vector<std::string> &keys)
 332   {
 333     std::vector<const char *> real_keys;
 334     std::vector<size_t> key_len;
 335     /*
 336      * Construct an array which will contain the length
 337      * of each of the strings in the input vector. Also, to
 338      * interface with the memcached C API, we need to convert
 339      * the vector of std::string's to a vector of char *.
 340      */
 341     real_keys.reserve(keys.size());
 342     key_len.reserve(keys.size());
 343
 344     std::vector<std::string>::iterator it= keys.begin();
 345
 346     while (it != keys.end())
 347     {
 348       real_keys.push_back(const_cast<char *>((*it).c_str()));
 349       key_len.push_back((*it).length());
 350       ++it;
 351     }
 352
 353     /*
 354      * If the std::vector of keys is empty then we cannot
 355      * call memcached_mget as we will get undefined behavior.
 356      */
 357     if (! real_keys.empty())
 358     {
 359       memcached_return_t rc= memcached_mget(&memc, &real_keys[0], &key_len[0],
 360                                           real_keys.size());
 361       return (rc == MEMCACHED_SUCCESS);
 362     }
 363
 364     return false;
 365   }
 366
 367   /**
 368    * Writes an object to the server. If the object already exists, it will
 369    * overwrite the existing object. This method always returns true
 370    * when using non-blocking mode unless a network error occurs.
 371    *
 372    * @param[in] key key of object to write to server
 373    * @param[in] value value of object to write to server
 374    * @param[in] expiration time to keep the object stored in the server for
 375    * @param[in] flags flags to store with the object
 376    * @return true on succcess; false otherwise
 377    */
 378   bool set(const std::string &key,
 379            const std::vector<char> &value,
 380            time_t expiration,
 381            uint32_t flags) throw(Error)
 382   {
 383     if (key.empty() || value.empty())
 384     {
 385       throw(Error("the key or value supplied is empty!", false));
 386     }
 387     memcached_return_t rc= memcached_set(&memc,
 388                                        key.c_str(), key.length(),
 389                                        &value[0], value.size(),
 390                                        expiration, flags);
 391     return (rc == MEMCACHED_SUCCESS || rc == MEMCACHED_BUFFERED);
 392   }
 393
 394   /**
 395    * Writes an object to a server specified by the master_key parameter.
 396    * If the object already exists, it will overwrite the existing object.
 397    *
 398    * @param[in] master_key key that specifies server to write to
 399    * @param[in] key key of object to write to server
 400    * @param[in] value value of object to write to server
 401    * @param[in] expiration time to keep the object stored in the server for
 402    * @param[in] flags flags to store with the object
 403    * @return true on succcess; false otherwise
 404    */
 405   bool setByKey(const std::string &master_key,
 406                 const std::string &key,
 407                 const std::vector<char> &value,
 408                 time_t expiration,
 409                 uint32_t flags) throw(Error)
 410   {
 411     if (master_key.empty() ||
 412         key.empty() ||
 413         value.empty())
 414     {
 415       throw(Error("the key or value supplied is empty!", false));
 416     }
 417     memcached_return_t rc= memcached_set_by_key(&memc, master_key.c_str(),
 418                                               master_key.length(),
 419                                               key.c_str(), key.length(),
 420                                               &value[0], value.size(),
 421                                               expiration,
 422                                               flags);
 423     return (rc == MEMCACHED_SUCCESS);
 424   }
 425
 426   /**
 427    * Writes a list of objects to the server. Objects are specified by
 428    * 2 vectors - 1 vector of keys and 1 vector of values.
 429    *
 430    * @param[in] keys vector of keys of objects to write to server
 431    * @param[in] values vector of values of objects to write to server
 432    * @param[in] expiration time to keep the objects stored in server for
 433    * @param[in] flags flags to store with the objects
 434    * @return true on success; false otherwise
 435    */
 436   bool setAll(std::vector<std::string> &keys,
 437               std::vector< std::vector<char> *> &values,
 438               time_t expiration,
 439               uint32_t flags) throw(Error)
 440   {
 441     if (keys.size() != values.size())
 442     {
 443       throw(Error("The number of keys and values do not match!", false));
 444     }
 445     bool retval= true;
 446     std::vector<std::string>::iterator key_it= keys.begin();
 447     std::vector< std::vector<char> *>::iterator val_it= values.begin();
 448     while (key_it != keys.end())
 449     {
 450       retval= set((*key_it), *(*val_it), expiration, flags);
 451       if (retval == false)
 452       {
 453         return retval;
 454       }
 455       ++key_it;
 456       ++val_it;
 457     }
 458     return retval;
 459   }
 460
 461   /**
 462    * Writes a list of objects to the server. Objects are specified by
 463    * a map of keys to values.
 464    *
 465    * @param[in] key_value_map map of keys and values to store in server
 466    * @param[in] expiration time to keep the objects stored in server for
 467    * @param[in] flags flags to store with the objects
 468    * @return true on success; false otherwise
 469    */
 470   bool setAll(std::map<const std::string, std::vector<char> > &key_value_map,
 471               time_t expiration,
 472               uint32_t flags) throw(Error)
 473   {
 474     if (key_value_map.empty())
 475     {
 476       throw(Error("The key/values are not properly set!", false));
 477     }
 478     bool retval= true;
 479     std::map<const std::string, std::vector<char> >::iterator it=
 480       key_value_map.begin();
 481     while (it != key_value_map.end())
 482     {
 483       retval= set(it->first, it->second, expiration, flags);
 484       if (retval == false)
 485       {
 486         std::string err_buff("There was an error setting the key ");
 487         err_buff.append(it->first);
 488         throw(Error(err_buff, false));
 489       }
 490       ++it;
 491     }
 492     return true;
 493   }
 494
 495   /**
 496    * Increment the value of the object associated with the specified
 497    * key by the offset given. The resulting value is saved in the value
 498    * parameter.
 499    *
 500    * @param[in] key key of object in server whose value to increment
 501    * @param[in] offset amount to increment object's value by
 502    * @param[out] value store the result of the increment here
 503    * @return true on success; false otherwise
 504    */
 505   bool increment(const std::string &key, uint32_t offset, uint64_t *value) throw(Error)
 506   {
 507     if (key.empty())
 508     {
 509       throw(Error("the key supplied is empty!", false));
 510     }
 511     memcached_return_t rc= memcached_increment(&memc, key.c_str(), key.length(),
 512                                              offset, value);
 513     return (rc == MEMCACHED_SUCCESS);
 514   }
 515
 516   /**
 517    * Decrement the value of the object associated with the specified
 518    * key by the offset given. The resulting value is saved in the value
 519    * parameter.
 520    *
 521    * @param[in] key key of object in server whose value to decrement
 522    * @param[in] offset amount to increment object's value by
 523    * @param[out] value store the result of the decrement here
 524    * @return true on success; false otherwise
 525    */
 526   bool decrement(const std::string &key, uint32_t offset, uint64_t *value)
 527     throw(Error)
 528   {
 529     if (key.empty())
 530     {
 531       throw(Error("the key supplied is empty!", false));
 532     }
 533     memcached_return_t rc= memcached_decrement(&memc, key.c_str(),
 534                                              key.length(),
 535                                              offset, value);
 536     return (rc == MEMCACHED_SUCCESS);
 537   }
 538
 539
 540   /**
 541    * Add an object with the specified key and value to the server. This
 542    * function returns false if the object already exists on the server.
 543    *
 544    * @param[in] key key of object to add
 545    * @param[in] value of object to add
 546    * @return true on success; false otherwise
 547    */
 548   bool add(const std::string &key, const std::vector<char> &value)
 549     throw(Error)
 550   {
 551     if (key.empty() || value.empty())
 552     {
 553       throw(Error("the key or value supplied is empty!", false));
 554     }
 555     memcached_return_t rc= memcached_add(&memc, key.c_str(), key.length(),
 556                                        &value[0], value.size(), 0, 0);
 557     return (rc == MEMCACHED_SUCCESS);
 558   }
 559
 560   /**
 561    * Add an object with the specified key and value to the server. This
 562    * function returns false if the object already exists on the server. The
 563    * server to add the object to is specified by the master_key parameter.
 564    *
 565    * @param[in[ master_key key of server to add object to
 566    * @param[in] key key of object to add
 567    * @param[in] value of object to add
 568    * @return true on success; false otherwise
 569    */
 570   bool addByKey(const std::string &master_key,
 571                 const std::string &key,
 572                 const std::vector<char> &value) throw(Error)
 573   {
 574     if (master_key.empty() ||
 575         key.empty() ||
 576         value.empty())
 577     {
 578       throw(Error("the master key or key supplied is empty!", false));
 579     }
 580     memcached_return_t rc= memcached_add_by_key(&memc,
 581                                               master_key.c_str(),
 582                                               master_key.length(),
 583                                               key.c_str(),
 584                                               key.length(),
 585                                               &value[0],
 586                                               value.size(),
 587                                               0, 0);
 588     return (rc == MEMCACHED_SUCCESS);
 589   }
 590
 591   /**
 592    * Replaces an object on the server. This method only succeeds
 593    * if the object is already present on the server.
 594    *
 595    * @param[in] key key of object to replace
 596    * @param[in[ value value to replace object with
 597    * @return true on success; false otherwise
 598    */
 599   bool replace(const std::string &key, const std::vector<char> &value) throw(Error)
 600   {
 601     if (key.empty() ||
 602         value.empty())
 603     {
 604       throw(Error("the key or value supplied is empty!", false));
 605     }
 606     memcached_return_t rc= memcached_replace(&memc, key.c_str(), key.length(),
 607                                            &value[0], value.size(),
 608                                            0, 0);
 609     return (rc == MEMCACHED_SUCCESS);
 610   }
 611
 612   /**
 613    * Replaces an object on the server. This method only succeeds
 614    * if the object is already present on the server. The server
 615    * to replace the object on is specified by the master_key param.
 616    *
 617    * @param[in] master_key key of server to replace object on
 618    * @param[in] key key of object to replace
 619    * @param[in[ value value to replace object with
 620    * @return true on success; false otherwise
 621    */
 622   bool replaceByKey(const std::string &master_key,
 623                     const std::string &key,
 624                     const std::vector<char> &value)
 625   {
 626     if (master_key.empty() ||
 627         key.empty() ||
 628         value.empty())
 629     {
 630       throw(Error("the master key or key supplied is empty!", false));
 631     }
 632     memcached_return_t rc= memcached_replace_by_key(&memc,
 633                                                   master_key.c_str(),
 634                                                   master_key.length(),
 635                                                   key.c_str(),
 636                                                   key.length(),
 637                                                   &value[0],
 638                                                   value.size(),
 639                                                   0, 0);
 640     return (rc == MEMCACHED_SUCCESS);
 641   }
 642
 643   /**
 644    * Places a segment of data before the last piece of data stored.
 645    *
 646    * @param[in] key key of object whose value we will prepend data to
 647    * @param[in] value data to prepend to object's value
 648    * @return true on success; false otherwise
 649    */
 650   bool prepend(const std::string &key, const std::vector<char> &value)
 651     throw(Error)
 652   {
 653     if (key.empty() || value.empty())
 654     {
 655       throw(Error("the key or value supplied is empty!", false));
 656     }
 657     memcached_return_t rc= memcached_prepend(&memc, key.c_str(), key.length(),
 658                                            &value[0], value.size(), 0, 0);
 659     return (rc == MEMCACHED_SUCCESS);
 660   }
 661
 662   /**
 663    * Places a segment of data before the last piece of data stored. The
 664    * server on which the object where we will be prepending data is stored
 665    * on is specified by the master_key parameter.
 666    *
 667    * @param[in] master_key key of server where object is stored
 668    * @param[in] key key of object whose value we will prepend data to
 669    * @param[in] value data to prepend to object's value
 670    * @return true on success; false otherwise
 671    */
 672   bool prependByKey(const std::string &master_key,
 673                     const std::string &key,
 674                     const std::vector<char> &value)
 675       throw(Error)
 676   {
 677     if (master_key.empty() ||
 678         key.empty() ||
 679         value.empty())
 680     {
 681       throw(Error("the master key or key supplied is empty!", false));
 682     }
 683     memcached_return_t rc= memcached_prepend_by_key(&memc,
 684                                                   master_key.c_str(),
 685                                                   master_key.length(),
 686                                                   key.c_str(),
 687                                                   key.length(),
 688                                                   &value[0],
 689                                                   value.size(),
 690                                                   0,
 691                                                   0);
 692     return (rc == MEMCACHED_SUCCESS);
 693   }
 694
 695   /**
 696    * Places a segment of data at the end of the last piece of data stored.
 697    *
 698    * @param[in] key key of object whose value we will append data to
 699    * @param[in] value data to append to object's value
 700    * @return true on success; false otherwise
 701    */
 702   bool append(const std::string &key, const std::vector<char> &value)
 703     throw(Error)
 704   {
 705     if (key.empty() || value.empty())
 706     {
 707       throw(Error("the key or value supplied is empty!", false));
 708     }
 709     memcached_return_t rc= memcached_append(&memc,
 710                                           key.c_str(),
 711                                           key.length(),
 712                                           &value[0],
 713                                           value.size(),
 714                                           0, 0);
 715     return (rc == MEMCACHED_SUCCESS);
 716   }
 717
 718   /**
 719    * Places a segment of data at the end of the last piece of data stored. The
 720    * server on which the object where we will be appending data is stored
 721    * on is specified by the master_key parameter.
 722    *
 723    * @param[in] master_key key of server where object is stored
 724    * @param[in] key key of object whose value we will append data to
 725    * @param[in] value data to append to object's value
 726    * @return true on success; false otherwise
 727    */
 728   bool appendByKey(const std::string &master_key,
 729                    const std::string &key,
 730                    const std::vector<char> &value)
 731     throw(Error)
 732   {
 733     if (master_key.empty() ||
 734         key.empty() ||
 735         value.empty())
 736     {
 737       throw(Error("the master key or key supplied is empty!", false));
 738     }
 739     memcached_return_t rc= memcached_append_by_key(&memc,
 740                                                  master_key.c_str(),
 741                                                  master_key.length(),
 742                                                  key.c_str(),
 743                                                  key.length(),
 744                                                  &value[0],
 745                                                  value.size(),
 746                                                  0, 0);
 747     return (rc == MEMCACHED_SUCCESS);
 748   }
 749
 750   /**
 751    * Overwrite data in the server as long as the cas_arg value
 752    * is still the same in the server.
 753    *
 754    * @param[in] key key of object in server
 755    * @param[in] value value to store for object in server
 756    * @param[in] cas_arg "cas" value
 757    */
 758   bool cas(const std::string &key,
 759            const std::vector<char> &value,
 760            uint64_t cas_arg) throw(Error)
 761   {
 762     if (key.empty() || value.empty())
 763     {
 764       throw(Error("the key or value supplied is empty!", false));
 765     }
 766     memcached_return_t rc= memcached_cas(&memc, key.c_str(), key.length(),
 767                                        &value[0], value.size(),
 768                                        0, 0, cas_arg);
 769     return (rc == MEMCACHED_SUCCESS);
 770   }
 771
 772   /**
 773    * Overwrite data in the server as long as the cas_arg value
 774    * is still the same in the server. The server to use is
 775    * specified by the master_key parameter.
 776    *
 777    * @param[in] master_key specifies server to operate on
 778    * @param[in] key key of object in server
 779    * @param[in] value value to store for object in server
 780    * @param[in] cas_arg "cas" value
 781    */
 782   bool casByKey(const std::string &master_key,
 783                 const std::string &key,
 784                 const std::vector<char> &value,
 785                 uint64_t cas_arg) throw(Error)
 786   {
 787     if (master_key.empty() ||
 788         key.empty() ||
 789         value.empty())
 790     {
 791       throw(Error("the master key, key or value supplied is empty!", false));
 792     }
 793     memcached_return_t rc= memcached_cas_by_key(&memc,
 794                                               master_key.c_str(),
 795                                               master_key.length(),
 796                                               key.c_str(),
 797                                               key.length(),
 798                                               &value[0],
 799                                               value.size(),
 800                                               0, 0, cas_arg);
 801     return (rc == MEMCACHED_SUCCESS);
 802   }
 803
 804   /**
 805    * Delete an object from the server specified by the key given.
 806    *
 807    * @param[in] key key of object to delete
 808    * @return true on success; false otherwise
 809    */
 810   bool remove(const std::string &key) throw(Error)
 811   {
 812     if (key.empty())
 813     {
 814       throw(Error("the key supplied is empty!", false));
 815     }
 816     memcached_return_t rc= memcached_delete(&memc, key.c_str(), key.length(), 0);
 817     return (rc == MEMCACHED_SUCCESS);
 818   }
 819
 820   /**
 821    * Delete an object from the server specified by the key given.
 822    *
 823    * @param[in] key key of object to delete
 824    * @param[in] expiration time to delete the object after
 825    * @return true on success; false otherwise
 826    */
 827   bool remove(const std::string &key,
 828               time_t expiration) throw(Error)
 829   {
 830     if (key.empty())
 831     {
 832       throw(Error("the key supplied is empty!", false));
 833     }
 834     memcached_return_t rc= memcached_delete(&memc,
 835                                           key.c_str(),
 836                                           key.length(),
 837                                           expiration);
 838     return (rc == MEMCACHED_SUCCESS);
 839   }
 840
 841   /**
 842    * Delete an object from the server specified by the key given.
 843    *
 844    * @param[in] master_key specifies server to remove object from
 845    * @param[in] key key of object to delete
 846    * @return true on success; false otherwise
 847    */
 848   bool removeByKey(const std::string &master_key,
 849                    const std::string &key) throw(Error)
 850   {
 851     if (master_key.empty() || key.empty())
 852     {
 853       throw(Error("the master key or key supplied is empty!", false));
 854     }
 855     memcached_return_t rc= memcached_delete_by_key(&memc,
 856                                                  master_key.c_str(),
 857                                                  master_key.length(),
 858                                                  key.c_str(),
 859                                                  key.length(),
 860                                                  0);
 861     return (rc == MEMCACHED_SUCCESS);
 862   }
 863
 864   /**
 865    * Delete an object from the server specified by the key given.
 866    *
 867    * @param[in] master_key specifies server to remove object from
 868    * @param[in] key key of object to delete
 869    * @param[in] expiration time to delete the object after
 870    * @return true on success; false otherwise
 871    */
 872   bool removeByKey(const std::string &master_key,
 873                    const std::string &key,
 874                    time_t expiration) throw(Error)
 875   {
 876     if (master_key.empty() || key.empty())
 877     {
 878       throw(Error("the master key or key supplied is empty!", false));
 879     }
 880     memcached_return_t rc= memcached_delete_by_key(&memc,
 881                                                  master_key.c_str(),
 882                                                  master_key.length(),
 883                                                  key.c_str(),
 884                                                  key.length(),
 885                                                  expiration);
 886     return (rc == MEMCACHED_SUCCESS);
 887   }
 888
 889   /**
 890    * Wipe the contents of memcached servers.
 891    *
 892    * @param[in] expiration time to wait until wiping contents of
 893    *                       memcached servers
 894    * @return true on success; false otherwise
 895    */
 896   bool flush(time_t expiration)
 897   {
 898     memcached_return_t rc= memcached_flush(&memc, expiration);
 899     return (rc == MEMCACHED_SUCCESS);
 900   }
 901
 902   /**
 903    * Callback function for result sets. It passes the result
 904    * sets to the list of functions provided.
 905    *
 906    * @param[in] callback list of callback functions
 907    * @param[in] context pointer to memory reference that is
 908    *                    supplied to the calling function
 909    * @param[in] num_of_callbacks number of callback functions
 910    * @return true on success; false otherwise
 911    */
 912   bool fetchExecute(memcached_execute_fn *callback,
 913                     void *context,
 914                     uint32_t num_of_callbacks)
 915   {
 916     memcached_return_t rc= memcached_fetch_execute(&memc,
 917                                                  callback,
 918                                                  context,
 919                                                  num_of_callbacks);
 920     return (rc == MEMCACHED_SUCCESS);
 921   }
 922
 923   /**
 924    * Get the library version string.
 925    * @return std::string containing a copy of the library version string.
 926    */
 927   const std::string libVersion() const
 928   {
 929     const char *ver= memcached_lib_version();
 930     const std::string version(ver);
 931     return version;
 932   }
 933
 934   /**
 935    * Retrieve memcached statistics. Populate a std::map with the retrieved
 936    * stats. Each server will map to another std::map of the key:value stats.
 937    *
 938    * @param[out] stats_map a std::map to be populated with the memcached
 939    *                       stats
 940    * @return true on success; false otherwise
 941    */
 942   bool getStats(std::map< std::string, std::map<std::string, std::string> >
 943                 &stats_map)
 944   {
 945     memcached_return_t rc;
 946     memcached_stat_st *stats= memcached_stat(&memc, NULL, &rc);
 947
 948     if (rc != MEMCACHED_SUCCESS &&
 949         rc != MEMCACHED_SOME_ERRORS)
 950     {
 951       return false;
 952     }
 953
 954     uint32_t server_count= memcached_server_count(&memc);
 955
 956     /*
 957      * For each memcached server, construct a std::map for its stats and add
 958      * it to the std::map of overall stats.
 959      */
 960     for (uint32_t x= 0; x < server_count; x++)
 961     {
 962       memcached_server_instance_st instance=
 963         memcached_server_instance_by_position(&memc, x);
 964       std::ostringstream strstm;
 965       std::string server_name(memcached_server_name(instance));
 966       server_name.append(":");
 967       strstm << memcached_server_port(instance);
 968       server_name.append(strstm.str());
 969
 970       std::map<std::string, std::string> server_stats;
 971       char **list= NULL;
 972       char **ptr= NULL;
 973
 974       list= memcached_stat_get_keys(&memc, &stats[x], &rc);
 975       for (ptr= list; *ptr; ptr++)
 976       {
 977         char *value= memcached_stat_get_value(&memc, &stats[x], *ptr, &rc);
 978         server_stats[*ptr]= value;
 979         free(value);
 980       }
 981
 982       stats_map[server_name]= server_stats;
 983       free(list);
 984     }
 985
 986     memcached_stat_free(&memc, stats);
 987     return true;
 988   }
 989
 990 private:
 991
 992   std::string servers_list;
 993   memcached_st memc;
 994   memcached_result_st result;
 995 };
 996
 997 }
 998
 999 #endif /* LIBMEMCACHEDPP_H */