Lib.rs

near-internal-balances-plugin建立在Near Accounts库之上，允许用户将FTs、NFTs和MTs存入合约并保持余额列表。例如，当alice.near调用实现Near内部余额的合约的ft_transfer_call时，合约将“记住”Alice转发了多少。一个用例示例是在Ref Finance中，用户需要将代币存入DEX智能合约以进行交换等。

使用非常简单，以下是一个基本示例

use near_account::{
    impl_near_accounts_plugin, AccountDeposits, AccountInfoTrait, Accounts, NearAccountPlugin,
    NearAccountsPluginNonExternal, NewInfo,
};
use near_internal_balances_plugin::impl_near_balance_plugin;

use near_contract_standards::storage_management::StorageManagement;
use near_internal_balances_plugin::token_id::TokenId;
use near_sdk::borsh::{self, BorshDeserialize, BorshSerialize};
use near_sdk::collections::{LazyOption, UnorderedMap};
use near_sdk::json_types::U128;
use near_sdk::{
    assert_one_yocto, env, log, near_bindgen, AccountId, Balance, PanicOnDefault, PromiseOrValue,
};

#[derive(BorshDeserialize, BorshSerialize)]
pub struct AccountInfo {
    pub internal_balance: UnorderedMap<TokenId, Balance>,
}

impl NewInfo for AccountInfo {
    fn default_from_account_id(account_id: AccountId) -> Self {
        Self {
            internal_balance: UnorderedMap::new(format!("{}-bal", account_id).as_bytes()),
        }
    }
}
#[near_bindgen]
#[derive(BorshDeserialize, BorshSerialize, PanicOnDefault)]
pub struct Contract {
    pub accounts: Accounts<AccountInfo>,
}

impl_near_accounts_plugin!(Contract, accounts, AccountInfo);
impl_near_balance_plugin!(Contract, accounts, AccountInfo, internal_balance);

顺便说一下，由于这是基于Near-Accounts，用户需要向智能合约注册自己以处理存储。有关更多信息，请参阅Near Accounts文档。