-class Memcache
-{
-public:
-
- Memcache()
- :
- servers_list(),
- memc(),
- servers(NULL),
- result()
- {
- memcached_create(&memc);
- }
-
- Memcache(const std::string &in_servers_list)
- :
- servers_list(in_servers_list),
- memc(),
- servers(NULL),
- result()
- {
- memcached_create(&memc);
- servers= memcached_servers_parse(servers_list.c_str());
- memcached_server_push(&memc, servers);
- }
-
- Memcache(const std::string &hostname,
- unsigned int port)
- :
- servers_list(),
- memc(),
- servers(NULL),
- result()
- {
- memcached_create(&memc);
- servers_list.append(hostname);
- servers_list.append(":");
- std::ostringstream strsmt;
- strsmt << port;
- servers_list.append(strsmt.str());
- servers= memcached_servers_parse(servers_list.c_str());
- memcached_server_push(&memc, servers);
- }
-
- Memcache(memcached_st *clone)
- :
- servers_list(),
- memc(),
- servers(NULL),
- result()
- {
- memcached_clone(&memc, clone);
- }
-
- Memcache(const Memcache &rhs)
- :
- servers_list(rhs.servers_list),
- memc(),
- servers(NULL),
- result()
- {
- memcached_clone(&memc, const_cast<memcached_st *>(&rhs.getImpl()));
- servers= memcached_servers_parse(servers_list.c_str());
- memcached_server_push(&memc, servers);
- }
-
- Memcache &operator=(const Memcache &rhs)
- {
- if (this != &rhs)
- {
- memcached_clone(&memc, const_cast<memcached_st *>(&rhs.getImpl()));
- servers= memcached_servers_parse(servers_list.c_str());
- memcached_server_push(&memc, servers);
- }
- return *this;
- }
-
- ~Memcache()
- {
- memcached_free(&memc);
- memcached_server_list_free(servers);
- }
-
- /**
- * Get the internal memcached_st *
- */
- memcached_st &getImpl()
- {
- return memc;
- }
-
- /**
- * Get the internal memcached_st *
- */
- const memcached_st &getImpl() const
- {
- return memc;
- }
-
- /**
- * Return an error string for the given return structure.
- *
- * @param[in] rc a memcached_return structure
- * @return error string corresponding to given return code in the library.
- */
- const std::string getError(memcached_return rc) const
- {
- /* first parameter to strerror is unused */
- return memcached_strerror(NULL, rc);
- }
-
- /**
- * Return the string which contains the list of memcached servers being
- * used.
- *
- * @return a std::string containing the list of memcached servers
- */
- const std::string getServersList() const
- {
- return servers_list;
- }
-
- /**
- * Set the list of memcached servers to use.
- *
- * @param[in] in_servers_list list of servers
- * @return true on success; false otherwise
- */
- bool setServers(const std::string &in_servers_list)
- {
- servers_list.assign(in_servers_list);
- servers= memcached_servers_parse(in_servers_list.c_str());
- return (servers == NULL);
- }
-
- /**
- * Add a server to the list of memcached servers to use.
- *
- * @param[in] server_name name of the server to add
- * @param[in[ port port number of server to add
- * @return true on success; false otherwise
- */
- bool addServer(const std::string &server_name, unsigned int port)
- {
- memcached_return rc;
- std::ostringstream strstm;
- servers_list.append(",");
- servers_list.append(server_name);
- servers_list.append(":");
- strstm << port;
- servers_list.append(strstm.str());
- servers= memcached_server_list_append(servers,
- server_name.c_str(),
- port,
- &rc);
- return (rc == MEMCACHED_SUCCESS);
- }
-
- /**
- * Fetches an individual value from the server. mget() must always
- * be called before using this method.
- *
- * @param[in] key key of object to fetch
- * @param[out] ret_val store returned object in this vector
- * @return a memcached return structure
- */
- memcached_return fetch(std::string &key,
- std::vector<char> &ret_val)
- {
- char ret_key[MEMCACHED_MAX_KEY];
- size_t value_length= 0;
- size_t key_length= 0;
- memcached_return rc;
- uint32_t flags= 0;
- char *value= memcached_fetch(&memc, ret_key, &key_length,
- &value_length, &flags, &rc);
- if (value && ret_val.empty())
- {
- ret_val.reserve(value_length);
- ret_val.assign(value, value + value_length);
- key.assign(ret_key);
- }
- return rc;
- }
-
- /**
- * Fetches an individual value from the server.
- *
- * @param[in] key key of object whose value to get
- * @param[out] ret_val object that is retrieved is stored in
- * this vector
- * @return true on success; false otherwise
- */
- bool get(const std::string &key,
- std::vector<char> &ret_val) throw (Error)
- {
- uint32_t flags= 0;
- memcached_return rc;
- size_t value_length= 0;
-
- if (key.empty())
- {
- throw(Error("the key supplied is empty!", false));
- }
- char *value= memcached_get(&memc, key.c_str(), key.length(),
- &value_length, &flags, &rc);
- if (value != NULL && ret_val.empty())
- {
- ret_val.reserve(value_length);
- ret_val.assign(value, value + value_length);
- return true;
- }
- return false;
- }
-
- /**
- * Fetches an individual from a server which is specified by
- * the master_key parameter that is used for determining which
- * server an object was stored in if key partitioning was
- * used for storage.
- *
- * @param[in] master_key key that specifies server object is stored on
- * @param[in] key key of object whose value to get
- * @param[out] ret_val object that is retrieved is stored in
- * this vector
- * @return true on success; false otherwise
- */
- bool getByKey(const std::string &master_key,
- const std::string &key,
- std::vector<char> &ret_val) throw(Error)
- {
- uint32_t flags= 0;
- memcached_return rc;
- size_t value_length= 0;
-
- if (master_key.empty() || key.empty())
- {
- throw(Error("the master key or key supplied is empty!", false));
- }
- char *value= memcached_get_by_key(&memc,
- master_key.c_str(), master_key.length(),
- key.c_str(), key.length(),
- &value_length, &flags, &rc);
- if (value)
- {
- ret_val.reserve(value_length);
- ret_val.assign(value, value + value_length);
- return true;
- }
- return false;
- }
-
- /**
- * Selects multiple keys at once. This method always
- * works asynchronously.
- *
- * @param[in] keys vector of keys to select
- * @return true if all keys are found
- */
- bool mget(std::vector<std::string> &keys)
- {
- std::vector<const char *> real_keys;
- std::vector<size_t> key_len;
- /*
- * Construct an array which will contain the length
- * of each of the strings in the input vector. Also, to
- * interface with the memcached C API, we need to convert
- * the vector of std::string's to a vector of char *.
- */
- real_keys.reserve(keys.size());
- key_len.reserve(keys.size());
-
- std::vector<std::string>::iterator it= keys.begin();
-
- while (it != keys.end())
- {
- real_keys.push_back(const_cast<char *>((*it).c_str()));
- key_len.push_back((*it).length());
- ++it;
- }
-
- /*
- * If the std::vector of keys is empty then we cannot
- * call memcached_mget as we will get undefined behavior.
- */
- if (! real_keys.empty())
- {
- memcached_return rc= memcached_mget(&memc, &real_keys[0], &key_len[0],
- real_keys.size());
- return (rc == MEMCACHED_SUCCESS);
- }
-
- return false;
- }
-
- /**
- * Writes an object to the server. If the object already exists, it will
- * overwrite the existing object. This method always returns true
- * when using non-blocking mode unless a network error occurs.
- *
- * @param[in] key key of object to write to server
- * @param[in] value value of object to write to server
- * @param[in] expiration time to keep the object stored in the server for
- * @param[in] flags flags to store with the object
- * @return true on succcess; false otherwise
- */
- bool set(const std::string &key,
- const std::vector<char> &value,
- time_t expiration,
- uint32_t flags) throw(Error)
- {
- if (key.empty() || value.empty())
- {
- throw(Error("the key or value supplied is empty!", false));
- }
- memcached_return rc= memcached_set(&memc,
- key.c_str(), key.length(),
- &value[0], value.size(),
- expiration, flags);
- return (rc == MEMCACHED_SUCCESS || rc == MEMCACHED_BUFFERED);
- }
-
- /**
- * Writes an object to a server specified by the master_key parameter.
- * If the object already exists, it will overwrite the existing object.
- *
- * @param[in] master_key key that specifies server to write to
- * @param[in] key key of object to write to server
- * @param[in] value value of object to write to server
- * @param[in] expiration time to keep the object stored in the server for
- * @param[in] flags flags to store with the object
- * @return true on succcess; false otherwise
- */
- bool setByKey(const std::string &master_key,
- const std::string &key,
- const std::vector<char> &value,
- time_t expiration,
- uint32_t flags) throw(Error)
- {
- if (master_key.empty() ||
- key.empty() ||
- value.empty())
- {
- throw(Error("the key or value supplied is empty!", false));
- }
- memcached_return rc= memcached_set_by_key(&memc, master_key.c_str(),
- master_key.length(),
- key.c_str(), key.length(),
- &value[0], value.size(),
- expiration,
- flags);
- return (rc == MEMCACHED_SUCCESS);
- }
-
- /**
- * Writes a list of objects to the server. Objects are specified by
- * 2 vectors - 1 vector of keys and 1 vector of values.
- *
- * @param[in] keys vector of keys of objects to write to server
- * @param[in] values vector of values of objects to write to server
- * @param[in] expiration time to keep the objects stored in server for
- * @param[in] flags flags to store with the objects
- * @return true on success; false otherwise
- */
- bool setAll(std::vector<std::string> &keys,
- std::vector< std::vector<char> *> &values,
- time_t expiration,
- uint32_t flags) throw(Error)
- {
- if (keys.size() != values.size())
- {
- throw(Error("The number of keys and values do not match!", false));
- }
- bool retval= true;
- std::vector<std::string>::iterator key_it= keys.begin();
- std::vector< std::vector<char> *>::iterator val_it= values.begin();
- while (key_it != keys.end())
- {
- retval= set((*key_it), *(*val_it), expiration, flags);
- if (retval == false)
- {
- return retval;
- }
- ++key_it;
- ++val_it;
- }
- return retval;
- }
-
- /**
- * Writes a list of objects to the server. Objects are specified by
- * a map of keys to values.
- *
- * @param[in] key_value_map map of keys and values to store in server
- * @param[in] expiration time to keep the objects stored in server for
- * @param[in] flags flags to store with the objects
- * @return true on success; false otherwise
- */
- bool setAll(std::map<const std::string, std::vector<char> > &key_value_map,
- time_t expiration,
- uint32_t flags) throw(Error)
- {
- if (key_value_map.empty())
- {
- throw(Error("The key/values are not properly set!", false));
- }
- bool retval= true;
- std::map<const std::string, std::vector<char> >::iterator it=
- key_value_map.begin();
- while (it != key_value_map.end())
- {
- retval= set(it->first, it->second, expiration, flags);
- if (retval == false)
- {
- std::string err_buff("There was an error setting the key ");
- err_buff.append(it->first);
- throw(Error(err_buff, false));
- }
- ++it;
- }
- return true;
- }
-
- /**
- * Increment the value of the object associated with the specified
- * key by the offset given. The resulting value is saved in the value
- * parameter.
- *
- * @param[in] key key of object in server whose value to increment
- * @param[in] offset amount to increment object's value by
- * @param[out] value store the result of the increment here
- * @return true on success; false otherwise
- */
- bool increment(const std::string &key, uint32_t offset, uint64_t *value) throw(Error)
- {
- if (key.empty())
- {
- throw(Error("the key supplied is empty!", false));
- }
- memcached_return rc= memcached_increment(&memc, key.c_str(), key.length(),
- offset, value);
- return (rc == MEMCACHED_SUCCESS);
- }
-
- /**
- * Decrement the value of the object associated with the specified
- * key by the offset given. The resulting value is saved in the value
- * parameter.
- *
- * @param[in] key key of object in server whose value to decrement
- * @param[in] offset amount to increment object's value by
- * @param[out] value store the result of the decrement here
- * @return true on success; false otherwise
- */
- bool decrement(const std::string &key, uint32_t offset, uint64_t *value)
- throw(Error)
- {
- if (key.empty())
- {
- throw(Error("the key supplied is empty!", false));
- }
- memcached_return rc= memcached_decrement(&memc, key.c_str(),
- key.length(),
- offset, value);
- return (rc == MEMCACHED_SUCCESS);
- }
-
-
- /**
- * Add an object with the specified key and value to the server. This
- * function returns false if the object already exists on the server.
- *
- * @param[in] key key of object to add
- * @param[in] value of object to add
- * @return true on success; false otherwise
- */
- bool add(const std::string &key, const std::vector<char> &value)
- throw(Error)
- {
- if (key.empty() || value.empty())
- {
- throw(Error("the key or value supplied is empty!", false));
- }
- memcached_return rc= memcached_add(&memc, key.c_str(), key.length(),
- &value[0], value.size(), 0, 0);
- return (rc == MEMCACHED_SUCCESS);
- }
-
- /**
- * Add an object with the specified key and value to the server. This
- * function returns false if the object already exists on the server. The
- * server to add the object to is specified by the master_key parameter.
- *
- * @param[in[ master_key key of server to add object to
- * @param[in] key key of object to add
- * @param[in] value of object to add
- * @return true on success; false otherwise
- */
- bool addByKey(const std::string &master_key,
- const std::string &key,
- const std::vector<char> &value) throw(Error)
- {
- if (master_key.empty() ||
- key.empty() ||
- value.empty())
- {
- throw(Error("the master key or key supplied is empty!", false));
- }
- memcached_return rc= memcached_add_by_key(&memc,
- master_key.c_str(),
- master_key.length(),
- key.c_str(),
- key.length(),
- &value[0],
- value.size(),
- 0, 0);
- return (rc == MEMCACHED_SUCCESS);
- }
-
- /**
- * Replaces an object on the server. This method only succeeds
- * if the object is already present on the server.
- *
- * @param[in] key key of object to replace
- * @param[in[ value value to replace object with
- * @return true on success; false otherwise
- */
- bool replace(const std::string &key, const std::vector<char> &value) throw(Error)
- {
- if (key.empty() ||
- value.empty())
- {
- throw(Error("the key or value supplied is empty!", false));
- }
- memcached_return rc= memcached_replace(&memc, key.c_str(), key.length(),
- &value[0], value.size(),
- 0, 0);
- return (rc == MEMCACHED_SUCCESS);
- }
-
- /**
- * Replaces an object on the server. This method only succeeds
- * if the object is already present on the server. The server
- * to replace the object on is specified by the master_key param.
- *
- * @param[in] master_key key of server to replace object on
- * @param[in] key key of object to replace
- * @param[in[ value value to replace object with
- * @return true on success; false otherwise
- */
- bool replaceByKey(const std::string &master_key,
- const std::string &key,
- const std::vector<char> &value)
- {
- if (master_key.empty() ||
- key.empty() ||
- value.empty())
- {
- throw(Error("the master key or key supplied is empty!", false));
- }
- memcached_return rc= memcached_replace_by_key(&memc,
- master_key.c_str(),
- master_key.length(),
- key.c_str(),
- key.length(),
- &value[0],
- value.size(),
- 0, 0);
- return (rc == MEMCACHED_SUCCESS);
- }
-
- /**
- * Places a segment of data before the last piece of data stored.
- *
- * @param[in] key key of object whose value we will prepend data to
- * @param[in] value data to prepend to object's value
- * @return true on success; false otherwise
- */
- bool prepend(const std::string &key, const std::vector<char> &value)
- throw(Error)
- {
- if (key.empty() || value.empty())
- {
- throw(Error("the key or value supplied is empty!", false));
- }
- memcached_return rc= memcached_prepend(&memc, key.c_str(), key.length(),
- &value[0], value.size(), 0, 0);
- return (rc == MEMCACHED_SUCCESS);
- }
-
- /**
- * Places a segment of data before the last piece of data stored. The
- * server on which the object where we will be prepending data is stored
- * on is specified by the master_key parameter.
- *
- * @param[in] master_key key of server where object is stored
- * @param[in] key key of object whose value we will prepend data to
- * @param[in] value data to prepend to object's value
- * @return true on success; false otherwise
- */
- bool prependByKey(const std::string &master_key,
- const std::string &key,
- const std::vector<char> &value)
- throw(Error)
- {
- if (master_key.empty() ||
- key.empty() ||
- value.empty())
- {
- throw(Error("the master key or key supplied is empty!", false));
- }
- memcached_return rc= memcached_prepend_by_key(&memc,
- master_key.c_str(),
- master_key.length(),
- key.c_str(),
- key.length(),
- &value[0],
- value.size(),
- 0,
- 0);
- return (rc == MEMCACHED_SUCCESS);
- }
-
- /**
- * Places a segment of data at the end of the last piece of data stored.
- *
- * @param[in] key key of object whose value we will append data to
- * @param[in] value data to append to object's value
- * @return true on success; false otherwise
- */
- bool append(const std::string &key, const std::vector<char> &value)
- throw(Error)
- {
- if (key.empty() || value.empty())
- {
- throw(Error("the key or value supplied is empty!", false));
- }
- memcached_return rc= memcached_append(&memc,
- key.c_str(),
- key.length(),
- &value[0],
- value.size(),
- 0, 0);
- return (rc == MEMCACHED_SUCCESS);
- }
-
- /**
- * Places a segment of data at the end of the last piece of data stored. The
- * server on which the object where we will be appending data is stored
- * on is specified by the master_key parameter.
- *
- * @param[in] master_key key of server where object is stored
- * @param[in] key key of object whose value we will append data to
- * @param[in] value data to append to object's value
- * @return true on success; false otherwise
- */
- bool appendByKey(const std::string &master_key,
- const std::string &key,
- const std::vector<char> &value)
- throw(Error)
- {
- if (master_key.empty() ||
- key.empty() ||
- value.empty())
- {
- throw(Error("the master key or key supplied is empty!", false));
- }
- memcached_return rc= memcached_append_by_key(&memc,
- master_key.c_str(),
- master_key.length(),
- key.c_str(),
- key.length(),
- &value[0],
- value.size(),
- 0, 0);
- return (rc == MEMCACHED_SUCCESS);
- }
-
- /**
- * Overwrite data in the server as long as the cas_arg value
- * is still the same in the server.
- *
- * @param[in] key key of object in server
- * @param[in] value value to store for object in server
- * @param[in] cas_arg "cas" value
- */
- bool cas(const std::string &key,
- const std::vector<char> &value,
- uint64_t cas_arg) throw(Error)
- {
- if (key.empty() || value.empty())
- {
- throw(Error("the key or value supplied is empty!", false));
- }
- memcached_return rc= memcached_cas(&memc, key.c_str(), key.length(),
- &value[0], value.size(),
- 0, 0, cas_arg);
- return (rc == MEMCACHED_SUCCESS);
- }
-
- /**
- * Overwrite data in the server as long as the cas_arg value
- * is still the same in the server. The server to use is
- * specified by the master_key parameter.
- *
- * @param[in] master_key specifies server to operate on
- * @param[in] key key of object in server
- * @param[in] value value to store for object in server
- * @param[in] cas_arg "cas" value
- */
- bool casByKey(const std::string &master_key,
- const std::string &key,
- const std::vector<char> &value,
- uint64_t cas_arg) throw(Error)
- {
- if (master_key.empty() ||
- key.empty() ||
- value.empty())
- {
- throw(Error("the master key, key or value supplied is empty!", false));
- }
- memcached_return rc= memcached_cas_by_key(&memc,
- master_key.c_str(),
- master_key.length(),
- key.c_str(),
- key.length(),
- &value[0],
- value.size(),
- 0, 0, cas_arg);
- return (rc == MEMCACHED_SUCCESS);
- }
-
- /**
- * Delete an object from the server specified by the key given.
- *
- * @param[in] key key of object to delete
- * @return true on success; false otherwise
- */
- bool remove(const std::string &key) throw(Error)
- {
- if (key.empty())
- {
- throw(Error("the key supplied is empty!", false));
- }
- memcached_return rc= memcached_delete(&memc, key.c_str(), key.length(), 0);
- return (rc == MEMCACHED_SUCCESS);
- }
-
- /**
- * Delete an object from the server specified by the key given.
- *
- * @param[in] key key of object to delete
- * @param[in] expiration time to delete the object after
- * @return true on success; false otherwise
- */
- bool remove(const std::string &key,
- time_t expiration) throw(Error)
- {
- if (key.empty())
- {
- throw(Error("the key supplied is empty!", false));
- }
- memcached_return rc= memcached_delete(&memc,
- key.c_str(),
- key.length(),
- expiration);
- return (rc == MEMCACHED_SUCCESS);
- }
-
- /**
- * Delete an object from the server specified by the key given.
- *
- * @param[in] master_key specifies server to remove object from
- * @param[in] key key of object to delete
- * @return true on success; false otherwise
- */
- bool removeByKey(const std::string &master_key,
- const std::string &key) throw(Error)
- {
- if (master_key.empty() || key.empty())
- {
- throw(Error("the master key or key supplied is empty!", false));
- }
- memcached_return rc= memcached_delete_by_key(&memc,
- master_key.c_str(),
- master_key.length(),
- key.c_str(),
- key.length(),
- 0);
- return (rc == MEMCACHED_SUCCESS);
- }
-
- /**
- * Delete an object from the server specified by the key given.
- *
- * @param[in] master_key specifies server to remove object from
- * @param[in] key key of object to delete
- * @param[in] expiration time to delete the object after
- * @return true on success; false otherwise
- */
- bool removeByKey(const std::string &master_key,
- const std::string &key,
- time_t expiration) throw(Error)
- {
- if (master_key.empty() || key.empty())
- {
- throw(Error("the master key or key supplied is empty!", false));
- }
- memcached_return rc= memcached_delete_by_key(&memc,
- master_key.c_str(),
- master_key.length(),
- key.c_str(),
- key.length(),
- expiration);
- return (rc == MEMCACHED_SUCCESS);
- }
-
- /**
- * Wipe the contents of memcached servers.
- *
- * @param[in] expiration time to wait until wiping contents of
- * memcached servers
- * @return true on success; false otherwise
- */
- bool flush(time_t expiration)
- {
- memcached_return rc= memcached_flush(&memc, expiration);
- return (rc == MEMCACHED_SUCCESS);
- }
-
- /**
- * Callback function for result sets. It passes the result
- * sets to the list of functions provided.
- *
- * @param[in] callback list of callback functions
- * @param[in] context pointer to memory reference that is
- * supplied to the calling function
- * @param[in] num_of_callbacks number of callback functions
- * @return true on success; false otherwise
- */
- bool fetchExecute(memcached_execute_function *callback,
- void *context,
- unsigned int num_of_callbacks)
- {
- memcached_return rc= memcached_fetch_execute(&memc,
- callback,
- context,
- num_of_callbacks);
- return (rc == MEMCACHED_SUCCESS);
- }
-
- /**
- * Get the library version string.
- * @return std::string containing a copy of the library version string.
- */
- const std::string libVersion() const
- {
- const char *ver= memcached_lib_version();
- const std::string version(ver);
- return version;
- }
-
-private: