use crate::{
base::{encode_function_data, AbiError, BaseContract},
call::ContractCall,
event::{EthEvent, Event},
EthLogDecode,
};
use ethers_core::{
abi::{Abi, Detokenize, Error, EventExt, Function, Tokenize},
types::{Address, Filter, Selector, ValueOrArray},
};
#[cfg(not(feature = "legacy"))]
use ethers_core::types::Eip1559TransactionRequest;
#[cfg(feature = "legacy")]
use ethers_core::types::TransactionRequest;
use ethers_providers::Middleware;
use std::{fmt::Debug, marker::PhantomData, sync::Arc};
/// A Contract is an abstraction of an executable program on the Ethereum Blockchain.
/// It has code (called byte code) as well as allocated long-term memory
/// (called storage). Every deployed Contract has an address, which is used to connect
/// to it so that it may be sent messages to call its methods.
///
/// A Contract can emit Events, which can be efficiently observed by applications
/// to be notified when a contract has performed specific operation.
///
/// There are two types of methods that can be called on a Contract:
///
/// 1. A Constant method may not add, remove or change any data in the storage,
/// nor log any events, and may only call Constant methods on other contracts.
/// These methods are free (no Ether is required) to call. The result from them
/// may also be returned to the caller. Constant methods are marked as `pure` and
/// `view` in Solidity.
///
/// 2. A Non-Constant method requires a fee (in Ether) to be paid, but may perform
/// any state-changing operation desired, log events, send ether and call Non-Constant
/// methods on other Contracts. These methods cannot return their result to the caller.
/// These methods must be triggered by a transaction, sent by an Externally Owned Account
/// (EOA) either directly or indirectly (i.e. called from another contract), and are
/// required to be mined before the effects are present. Therefore, the duration
/// required for these operations can vary widely, and depend on the transaction
/// gas price, network congestion and miner priority heuristics.
///
/// The Contract API provides simple way to connect to a Contract and call its methods,
/// as functions on a Rust struct, handling all the binary protocol conversion,
/// internal name mangling and topic construction. This allows a Contract object
/// to be used like any standard Rust struct, without having to worry about the
/// low-level details of the Ethereum Virtual Machine or Blockchain.
///
/// The Contract definition (called an Application Binary Interface, or ABI) must
/// be provided to instantiate a contract and the available methods and events will
/// be made available to call by providing their name as a `str` via the [`method`]
/// and [`event`] methods. If non-existing names are given, the function/event call
/// will fail.
///
/// Alternatively, you can _and should_ use the [`abigen`] macro, or the [`Abigen` builder]
/// to generate type-safe bindings to your contracts.
///
/// # Example
///
/// Assuming we already have our contract deployed at `address`, we'll proceed to
/// interact with its methods and retrieve raw logs it has emitted.
///
/// ```no_run
/// use ethers_core::{
/// abi::Abi,
/// types::{Address, H256},
/// };
/// use ethers_contract::Contract;
/// use ethers_providers::{Provider, Http};
/// use ethers_signers::Wallet;
/// use std::convert::TryFrom;
///
/// # async fn foo() -> Result<(), Box<dyn std::error::Error>> {
/// // this is a fake address used just for this example
/// let address = "eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee".parse::<Address>()?;
///
/// // (ugly way to write the ABI inline, you can otherwise read it from a file)
/// let abi: Abi = serde_json::from_str(r#"[{"inputs":[{"internalType":"string","name":"value","type":"string"}],"stateMutability":"nonpayable","type":"constructor"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"author","type":"address"},{"indexed":true,"internalType":"address","name":"oldAuthor","type":"address"},{"indexed":false,"internalType":"string","name":"oldValue","type":"string"},{"indexed":false,"internalType":"string","name":"newValue","type":"string"}],"name":"ValueChanged","type":"event"},{"inputs":[],"name":"getValue","outputs":[{"internalType":"string","name":"","type":"string"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"lastSender","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"string","name":"value","type":"string"}],"name":"setValue","outputs":[],"stateMutability":"nonpayable","type":"function"}]"#)?;
///
/// // connect to the network
/// let client = Provider::<Http>::try_from("http://localhost:8545").unwrap();
///
/// // create the contract object at the address
/// let contract = Contract::new(address, abi, client);
///
/// // Calling constant methods is done by calling `call()` on the method builder.
/// // (if the function takes no arguments, then you must use `()` as the argument)
/// let init_value: String = contract
/// .method::<_, String>("getValue", ())?
/// .call()
/// .await?;
///
/// // Non-constant methods are executed via the `send()` call on the method builder.
/// let call = contract
/// .method::<_, H256>("setValue", "hi".to_owned())?;
/// let pending_tx = call.send().await?;
///
/// // `await`ing on the pending transaction resolves to a transaction receipt
/// let receipt = pending_tx.confirmations(6).await?;
///
/// # Ok(())
/// # }
/// ```
///
/// # Event Logging
/// Querying structured logs requires you to have defined a struct with the expected
/// datatypes and to have implemented `Detokenize` for it. This boilerplate code
/// is generated for you via the [`abigen`] and [`Abigen` builder] utilities.
///
/// ```ignore
/// # async fn foo() -> Result<(), Box<dyn std::error::Error>> {
/// use ethers_core::{abi::Abi, types::Address};
/// use ethers_contract::{Contract, EthEvent};
/// use ethers_providers::{Provider, Http, Middleware};
/// use ethers_signers::Wallet;
/// use std::convert::TryFrom;
/// use ethers_core::abi::{Detokenize, Token, InvalidOutputType};
/// # // this is a fake address used just for this example
/// # let address = "eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee".parse::<Address>()?;
/// # let abi: Abi = serde_json::from_str(r#"[]"#)?;
/// # let client = Provider::<Http>::try_from("http://localhost:8545").unwrap();
/// # let contract = Contract::new(address, abi, client);
///
/// #[derive(Clone, Debug, EthEvent)]
/// struct ValueChanged {
/// old_author: Address,
/// new_author: Address,
/// old_value: String,
/// new_value: String,
/// }
///
/// let logs: Vec<ValueChanged> = contract
/// .event()
/// .from_block(0u64)
/// .query()
/// .await?;
///
/// println!("{:?}", logs);
/// # Ok(())
/// # }
/// ```
///
/// _Disclaimer: these above docs have been adapted from the corresponding [ethers.js page](https://docs.ethers.io/ethers.js/html/api-contract.html)_
///
/// [`abigen`]: macro.abigen.html
/// [`Abigen` builder]: struct.Abigen.html
/// [`event`]: method@crate::Contract::event
/// [`method`]: method@crate::Contract::method
#[derive(Debug)]
pub struct Contract<M> {
address: Address,
base_contract: BaseContract,
client: Arc<M>,
}
impl<M> std::ops::Deref for Contract<M> {
type Target = BaseContract;
fn deref(&self) -> &Self::Target {
&self.base_contract
}
}
impl<M> Clone for Contract<M> {
fn clone(&self) -> Self {
Contract {
base_contract: self.base_contract.clone(),
client: self.client.clone(),
address: self.address,
}
}
}
impl<M> Contract<M> {
/// Returns the contract's address
pub fn address(&self) -> Address {
self.address
}
/// Returns a reference to the contract's ABI
pub fn abi(&self) -> &Abi {
&self.base_contract.abi
}
/// Returns a pointer to the contract's client
pub fn client(&self) -> Arc<M> {
self.client.clone()
}
}
impl<M: Middleware> Contract<M> {
/// Returns an [`Event`](crate::builders::Event) builder for the provided event.
/// This function operates in a static context, then it does not require a `self`
/// to reference to instantiate an [`Event`](crate::builders::Event) builder.
pub fn event_of_type<D: EthEvent>(client: &Arc<M>) -> Event<M, D> {
Event {
provider: client,
filter: Filter::new().event(&D::abi_signature()),
datatype: PhantomData,
}
}
}
impl<M: Middleware> Contract<M> {
/// Creates a new contract from the provided client, abi and address
pub fn new(
address: impl Into<Address>,
abi: impl Into<BaseContract>,
client: impl Into<Arc<M>>,
) -> Self {
Self { base_contract: abi.into(), client: client.into(), address: address.into() }
}
/// Returns an [`Event`](crate::builders::Event) builder for the provided event.
pub fn event<D: EthEvent>(&self) -> Event<M, D> {
self.event_with_filter(Filter::new().event(&D::abi_signature()))
}
/// Returns an [`Event`](crate::builders::Event) builder with the provided filter.
pub fn event_with_filter<D: EthLogDecode>(&self, filter: Filter) -> Event<M, D> {
Event {
provider: &self.client,
filter: filter.address(ValueOrArray::Value(self.address)),
datatype: PhantomData,
}
}
/// Returns an [`Event`](crate::builders::Event) builder with the provided name.
pub fn event_for_name<D: EthLogDecode>(&self, name: &str) -> Result<Event<M, D>, Error> {
// get the event's full name
let event = self.base_contract.abi.event(name)?;
Ok(self.event_with_filter(Filter::new().event(&event.abi_signature())))
}
/// Returns a transaction builder for the provided function name. If there are
/// multiple functions with the same name due to overloading, consider using
/// the `method_hash` method instead, since this will use the first match.
pub fn method<T: Tokenize, D: Detokenize>(
&self,
name: &str,
args: T,
) -> Result<ContractCall<M, D>, AbiError> {
// get the function
let function = self.base_contract.abi.function(name)?;
self.method_func(function, args)
}
/// Returns a transaction builder for the selected function signature. This should be
/// preferred if there are overloaded functions in your smart contract
pub fn method_hash<T: Tokenize, D: Detokenize>(
&self,
signature: Selector,
args: T,
) -> Result<ContractCall<M, D>, AbiError> {
let function = self
.base_contract
.methods
.get(&signature)
.map(|(name, index)| &self.base_contract.abi.functions[name][*index])
.ok_or_else(|| Error::InvalidName(hex::encode(signature)))?;
self.method_func(function, args)
}
fn method_func<T: Tokenize, D: Detokenize>(
&self,
function: &Function,
args: T,
) -> Result<ContractCall<M, D>, AbiError> {
let data = encode_function_data(function, args)?;
#[cfg(feature = "legacy")]
let tx = TransactionRequest {
to: Some(self.address.into()),
data: Some(data),
..Default::default()
};
#[cfg(not(feature = "legacy"))]
let tx = Eip1559TransactionRequest {
to: Some(self.address.into()),
data: Some(data),
..Default::default()
};
let tx = tx.into();
Ok(ContractCall {
tx,
client: Arc::clone(&self.client), // cheap clone behind the Arc
block: None,
function: function.to_owned(),
datatype: PhantomData,
})
}
/// Returns a new contract instance at `address`.
///
/// Clones `self` internally
#[must_use]
pub fn at<T: Into<Address>>(&self, address: T) -> Self
where
M: Clone,
{
let mut this = self.clone();
this.address = address.into();
this
}
/// Returns a new contract instance using the provided client
///
/// Clones `self` internally
#[must_use]
pub fn connect<N>(&self, client: Arc<N>) -> Contract<N>
where
N: Clone,
{
Contract { base_contract: self.base_contract.clone(), client, address: self.address }
}
}