多索引表 multi_index.hpp源代码

Posted 2021-10-28 thefist11

1. 在线hpp源代码

https://developers.eos.io/manuals/eosio.cdt/v1.7/group__multiindex

1.1 get_code和get_scope

//Returns the code member property.
name eosio::multi_index< TableName, T, Indices >::get_code() const

//Returns the scope member property.
uint64_t eosio::multi_index< TableName, T, Indices >::get_scope() const

1.2 迭代

const_iterator eosio::multi_index< TableName, T, Indices >::cbegin() const
const_iterator eosio::multi_index< TableName, T, Indices >::begin() const
const_iterator eosio::multi_index< TableName, T, Indices >::cend() const
const_iterator eosio::multi_index< TableName, T, Indices >::end() const

const_reverse_iterator eosio::multi_index< TableName, T, Indices >::crbegin() const
const_reverse_iterator eosio::multi_index< TableName, T, Indices >::rbegin() const
const_reverse_iterator eosio::multi_index< TableName, T, Indices >::crend() const
const_reverse_iterator eosio::multi_index< TableName, T, Indices >::rend() const

const_iterator eosio::multi_index< TableName, T, Indices >::lower_bound(
    uint64_t primary
) const

const_iterator eosio::multi_index< TableName, T, Indices >::upper_bound(
    uint64_t primary
) const

eg.

void myaction() {
      // create reference to address_index  - see emplace example below
      // add dan account to table           - see emplace example below
      // add additional account - brendan

      addresses.emplace(payer, [&](auto& address) {
        address.account_name = "brendan"_n;
        address.first_name = "Brendan";
        address.last_name = "Blumer";
        address.street = "1 EOS Way";
        address.city = "Hong Kong";
        address.state = "HK";
        address.zip = 93445;
      });
      uint32_t zipnumb = 93445;
      auto zip_index = addresses.get_index<name("zip")>();
      auto itr = zip_index.lower_bound(zipnumb);
      eosio::check(itr->account_name == name("brendan"), "Lock arf, Incorrect First Lower Bound Record ");
      itr++;
      eosio::check(itr->account_name == name("dan"), "Lock arf, Incorrect Second Lower Bound Record");
      itr++;
      eosio::check(itr == zip_index.end(), "Lock arf, Incorrect End of Iterator");
 }

1.3 available_primary_key

uint64_t eosio::multi_index< TableName, T, Indices >::available_primary_key() const

eg.

void myaction() {
      address_index addresses(_self, _self.value);  // code, scope
      // add to table, first argument is account to bill for storage
      addresses.emplace(payer, [&](auto& address) {
        address.key = addresses.available_primary_key();
        address.first_name = "Daniel";
        address.last_name = "Larimer";
        address.street = "1 EOS Way";
        address.city = "Blacksburg";
        address.state = "VA";
      });
}

1.4 get_index

template< IndexName> auto eosio::multi_index< TableName, T, Indices >::get_index()

eg.

#include <eosiolib/eosio.hpp>
using namespace eosio;
using namespace std;
class addressbook: contract {
  struct address {
     uint64_t account_name;
     string first_name;
     string last_name;
     string street;
     string city;
     string state;
     uint32_t zip = 0;
     uint64_t primary_key() const { return account_name; }
     uint64_t by_zip() const { return zip; }
  };
  public:
    addressbook(name receiver, name code, datastream<const char*> ds):contract(receiver, code, ds) {}
    typedef eosio::multi_index< name("address"), address, indexed_by< name("zip"), const_mem_fun<address, uint64_t, &address::by_zip> > address_index;
    void myaction() {
      // create reference to address_index  - see emplace example below
      // add dan account to table           - see emplace example below
      uint32_t zipnumb = 93446;
      auto zip_index = addresses.get_index<name("zip")>();
      auto itr = zip_index.find(zipnumb);
      eosio::check(itr->account_name == name("dan"), "Lock arf, Incorrect Record ");
    }
}
EOSIO_DISPATCH( addressbook, (myaction) )
 

// This assumes the code from the get_index() example. Replace myaction() {...}
void myaction() {
      // create reference to address_index  - see emplace example below
      // add dan account to table           - see emplace example below
      // add additional account - brendan

      addresses.emplace(payer, [&](auto& address) {
        address.account_name = "brendan"_n;
        address.first_name = "Brendan";
        address.last_name = "Blumer";
        address.street = "1 EOS Way";
        address.city = "Hong Kong";
        address.state = "HK";
        address.zip = 93445;
      });
      uint32_t zipnumb = 93445;
      auto zip_index = addresses.get_index<name("zip")>();
      auto itr = zip_index.upper_bound(zipnumb);
      eosio::check(itr->account_name == name("dan"), "Lock arf, Incorrect First Upper Bound Record ");
      itr++;
      eosio::check(itr == zip_index.end(), "Lock arf, Incorrect End of Iterator");
    }
}
EOSIO_DISPATCH( addressbook, (myaction) )

1.5 iterator_to

const_iterator eosio::multi_index< TableName, T, Indices >::iterator_to(
   const T & obj
) const

eg.

// This assumes the code from the get_index() example. Replace myaction() {...}
void myaction() {
      // create reference to address_index  - see emplace example below
      // add dan account to table           - see emplace example below
      // add additional account - brendan

      addresses.emplace(payer, [&](auto& address) {
        address.account_name = "brendan"_n;
        address.first_name = "Brendan";
        address.last_name = "Blumer";
        address.street = "1 EOS Way";
        address.city = "Hong Kong";
        address.state = "HK";
        address.zip = 93445;
      });
      auto user = addresses.get("dan"_n);
      auto itr = address.find("dan"_n);
      eosio::check(iterator_to(user) == itr, "Invalid iterator");
    }
}
EOSIO_DISPATCH( addressbook, (myaction) )

1.6 get

const T& eosio::multi_index< TableName, T, Indices >::get(
   uint64_t primary,
   const char * error_msg = "unable to find key"
) const

eg.

void myaction() {
      // create reference to address_index  - see emplace example
      // add dan account to table           - see emplace example

      auto user = addresses.get("dan"_n);
      eosio::check(user.first_name == "Daniel", "Couldn't get him.");
}