3_instantiate.md

instantiate

pub fn instantiate(deps: DepsMut, env:Env, info: MessageInfo, msg: InstantiateMsg)

DepsMut

pub struct DepsMut<'a, C: CustomQuery = Empty> {
   pub storage: &'a mut dyn Storage,
   pub api: &'a dyn Api,
   pub querier: QuerierWrapper<'a, C>,
}

DepsMut 是一种用于与外部世界通信的实用程序类型 - 它允许查询和更新合约状态、查询其他合约状态，并提供对 Api 对象的访问以及几个用于处理 CW 地址的辅助函数。

Env

#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq, JsonSchema)]
pub struct Env {
   pub block: BlockInfo,

   pub transaction: Option<TransactionInfo>,
   pub contract: ContractInfo,
}

Env 是一个代表执行消息时区块链状态的对象 - 链高度和 ID、当前时间戳和调用的合约地址。

MessageInfo

#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq)]
pub struct MessageInfo {

   pub sender: Addr,

   pub funds: Vec<Coin>,
}

MessageInfo 包含有关触发执行的消息的元信息 - 发送消息的地址以及与消息一起发送的链本机令牌。

InstantiateMsg

这个InstantiateMsg是用户自定义的。在本样例中

pub struct InstantiateMsg {
   pub admins: Vec<String>,
   pub donation_denom: String,
}

传递admins的地址数组和denom的类型。

返回值

Result<Response, ContractError> 

其中Result为：

pub enum Result<T, E> {
   /// Contains the success value
   #[lang = "Ok"]
   #[stable(feature = "rust1", since = "1.0.0")]
   Ok(#[stable(feature = "rust1", since = "1.0.0")] T),

   /// Contains the error value
   #[lang = "Err"]
   #[stable(feature = "rust1", since = "1.0.0")]
   Err(#[stable(feature = "rust1", since = "1.0.0")] E),
}

• Response

pub struct Response<T = Empty> {
    pub messages: Vec<SubMsg<T>>,
    pub attributes: Vec<Attribute>,
    pub events: Vec<Event>,
    pub data: Option<Binary>,
}

• 在样例中Err为定制的ContractError

pub enum ContractError {
   #[error("{0}")]
   StdError(#[from] StdError),
   #[error("{sender} is not contract admin")]
   Unauthorized { sender: Addr},
   #[error("Payment error: {0}")]
   Payment(#[from] PaymentError),
}

sample中instantiate逻辑

   let admins: StdResult<Vec<_>> = msg.admins.into_iter().map(|addr| deps.api.addr_validate(&addr)).collect();
   ADMINS.save(deps.storage, &admins?)?;
   DONATION_DENOM.save(deps.storage, &msg.donation_denom)?;
   Ok(Response::new())