Struct Call

pub struct Call<S, const HAS_VALUE: bool = false> { /* private fields */ }

👎Deprecated since 0.8.0: Use the Call struct defined in stylus_core::calls::context instead

Enables configurable calls to other contracts.

Implementations

impl<'a, S> Call<&'a mut S, false>

where S: TopLevelStorage + 'a,

pub fn new_in(storage: &'a mut S) -> Self

Similar to new, but intended for projects and libraries using reentrant patterns.

new_in safeguards persistent storage by requiring a reference to a TopLevelStorage struct.

Recall that TopLevelStorage is special in that a reference to it represents access to the entire contract’s state. So that it’s sound to flush or clear the StorageCache when calling out to other contracts, calls that may induce reentrancy require an & or &mut to one. Although this reference to TopLevelStorage is not used, the lifetime is still required to ensure safety of the storage cache.

use stylus_sdk::call::{Call, Error};
use stylus_sdk::{prelude::*, evm, msg, alloy_primitives::Address};
use stylus_core::storage::TopLevelStorage;
extern crate alloc;

sol_interface! {
    interface IService {
        function makePayment(address user) external payable returns (string);
    }
}

pub fn do_call(
    storage: &mut impl TopLevelStorage,  // can be generic, but often just &mut self
    account: IService,                   // serializes as an Address
    user: Address,
) -> Result<String, Error> {

    let config = Call::new_in(storage)
        .gas(evm::gas_left() / 2)        // limit to half the gas left
        .value(msg::value());            // set the callvalue

    account.make_payment(config, user)   // note the snake case
}

impl<S, const HAS_VALUE: bool> Call<S, HAS_VALUE>

pub fn gas(self, gas: u64) -> Self

Amount of gas to supply the call. Values greater than the amount provided will be clipped to all gas left.

pub fn value(self, value: U256) -> Call<S, true>

Amount of ETH in wei to give the other contract. Note: adding value will prevent calls to non-payable methods.

impl Call<(), false>

pub fn new() -> Self

Begin configuring a call, similar to how RawCall and std::fs::OpenOptions work.

This is not available if reentrant feature is enabled, as it may lead to vulnerability to reentrancy attacks. See Call::new_in.

use stylus_sdk::call::{Call, Error};
use stylus_sdk::{prelude::*, evm, msg, alloy_primitives::Address};
extern crate alloc;

sol_interface! {
    interface IService {
        function makePayment(address user) external payable returns (string);
    }
}

pub fn do_call(account: IService, user: Address) -> Result<String, Error> {
    let config = Call::new()
        .gas(evm::gas_left() / 2)       // limit to half the gas left
        .value(msg::value());           // set the callvalue

    account.make_payment(config, user)  // note the snake case
}

Trait Implementations

impl<S, const HAS_VALUE: bool> CallContext for Call<S, HAS_VALUE>

fn gas(&self) -> u64

Amount of gas to supply the call. Note: values are clipped to the amount of gas remaining.

impl<S: Clone, const HAS_VALUE: bool> Clone for Call<S, HAS_VALUE>

fn clone(&self) -> Call<S, HAS_VALUE>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<S: Debug, const HAS_VALUE: bool> Debug for Call<S, HAS_VALUE>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Call<(), false>

fn default() -> Self

Returns the “default value” for a type.

impl<S, const HAS_VALUE: bool> MutatingCallContext for Call<S, HAS_VALUE>

fn value(&self) -> U256

Amount of ETH in wei to give the other contract.

impl<S> NonPayableCallContext for Call<S, false>

impl<S> StaticCallContext for Call<S, false>