Trait pallet_contracts::api_doc::Current

pub trait Current {
    // Required methods
    fn deposit_event(
        topics_ptr: u32,
        topics_len: u32,
        data_ptr: u32,
        data_len: u32,
    ) -> Result<(), TrapReason>;
    fn ecdsa_recover(
        signature_ptr: u32,
        message_hash_ptr: u32,
        output_ptr: u32,
    ) -> Result<ReturnErrorCode, TrapReason>;
    fn call_runtime(
        call_ptr: u32,
        call_len: u32,
    ) -> Result<ReturnErrorCode, TrapReason>;
    fn clear_storage(key_ptr: u32, key_len: u32) -> Result<u32, TrapReason>;
    fn sr25519_verify(
        signature_ptr: u32,
        pub_key_ptr: u32,
        message_len: u32,
        message_ptr: u32,
    ) -> Result<ReturnErrorCode, TrapReason>;
    fn instantiation_nonce() -> Result<u64, TrapReason>;
    fn set_transient_storage(
        key_ptr: u32,
        key_len: u32,
        value_ptr: u32,
        value_len: u32,
    ) -> Result<u32, TrapReason>;
    fn caller_is_origin() -> Result<u32, TrapReason>;
    fn account_reentrance_count(account_ptr: u32) -> Result<u32, TrapReason>;
    fn get_transient_storage(
        key_ptr: u32,
        key_len: u32,
        out_ptr: u32,
        out_len_ptr: u32,
    ) -> Result<ReturnErrorCode, TrapReason>;
    fn ecdsa_to_eth_address(
        key_ptr: u32,
        out_ptr: u32,
    ) -> Result<ReturnErrorCode, TrapReason>;
    fn own_code_hash(out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason>;
    fn noop() -> Result<(), TrapReason>;
    fn seal_return(
        flags: u32,
        data_ptr: u32,
        data_len: u32,
    ) -> Result<(), TrapReason>;
    fn instantiate(
        code_hash_ptr: u32,
        ref_time_limit: u64,
        proof_size_limit: u64,
        deposit_ptr: u32,
        value_ptr: u32,
        input_data_ptr: u32,
        input_data_len: u32,
        address_ptr: u32,
        address_len_ptr: u32,
        output_ptr: u32,
        output_len_ptr: u32,
        salt_ptr: u32,
        salt_len: u32,
    ) -> Result<ReturnErrorCode, TrapReason>;
    fn call(
        flags: u32,
        callee_ptr: u32,
        ref_time_limit: u64,
        proof_size_limit: u64,
        deposit_ptr: u32,
        value_ptr: u32,
        input_data_ptr: u32,
        input_data_len: u32,
        output_ptr: u32,
        output_len_ptr: u32,
    ) -> Result<ReturnErrorCode, TrapReason>;
    fn address(out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason>;
    fn tombstone_deposit(
        out_ptr: u32,
        out_len_ptr: u32,
    ) -> Result<(), TrapReason>;
    fn input(out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason>;
    fn rent_allowance(out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason>;
    fn hash_sha2_256(
        input_ptr: u32,
        input_len: u32,
        output_ptr: u32,
    ) -> Result<(), TrapReason>;
    fn hash_keccak_256(
        input_ptr: u32,
        input_len: u32,
        output_ptr: u32,
    ) -> Result<(), TrapReason>;
    fn weight_to_fee(
        ref_time_limit: u64,
        proof_size_limit: u64,
        out_ptr: u32,
        out_len_ptr: u32,
    ) -> Result<(), TrapReason>;
    fn contains_storage(key_ptr: u32, key_len: u32) -> Result<u32, TrapReason>;
    fn set_code_hash(code_hash_ptr: u32) -> Result<ReturnErrorCode, TrapReason>;
    fn lock_delegate_dependency(code_hash_ptr: u32) -> Result<(), TrapReason>;
    fn hash_blake2_128(
        input_ptr: u32,
        input_len: u32,
        output_ptr: u32,
    ) -> Result<(), TrapReason>;
    fn unlock_delegate_dependency(code_hash_ptr: u32) -> Result<(), TrapReason>;
    fn value_transferred(
        out_ptr: u32,
        out_len_ptr: u32,
    ) -> Result<(), TrapReason>;
    fn take_storage(
        key_ptr: u32,
        key_len: u32,
        out_ptr: u32,
        out_len_ptr: u32,
    ) -> Result<ReturnErrorCode, TrapReason>;
    fn caller(out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason>;
    fn xcm_send(
        dest_ptr: u32,
        msg_ptr: u32,
        msg_len: u32,
        output_ptr: u32,
    ) -> Result<ReturnErrorCode, TrapReason>;
    fn reentrance_count() -> Result<u32, TrapReason>;
    fn set_rent_allowance(_value_ptr: u32) -> Result<(), TrapReason>;
    fn random(
        subject_ptr: u32,
        subject_len: u32,
        out_ptr: u32,
        out_len_ptr: u32,
    ) -> Result<(), TrapReason>;
    fn code_hash(
        account_ptr: u32,
        out_ptr: u32,
        out_len_ptr: u32,
    ) -> Result<ReturnErrorCode, TrapReason>;
    fn get_storage(
        key_ptr: u32,
        key_len: u32,
        out_ptr: u32,
        out_len_ptr: u32,
    ) -> Result<ReturnErrorCode, TrapReason>;
    fn now(out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason>;
    fn xcm_execute(
        msg_ptr: u32,
        msg_len: u32,
    ) -> Result<ReturnErrorCode, TrapReason>;
    fn terminate(beneficiary_ptr: u32) -> Result<(), TrapReason>;
    fn gas_left(out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason>;
    fn set_storage(
        key_ptr: u32,
        key_len: u32,
        value_ptr: u32,
        value_len: u32,
    ) -> Result<u32, TrapReason>;
    fn clear_transient_storage(
        key_ptr: u32,
        key_len: u32,
    ) -> Result<u32, TrapReason>;
    fn block_number(out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason>;
    fn debug_message(
        str_ptr: u32,
        str_len: u32,
    ) -> Result<ReturnErrorCode, TrapReason>;
    fn delegate_call(
        flags: u32,
        code_hash_ptr: u32,
        input_data_ptr: u32,
        input_data_len: u32,
        output_ptr: u32,
        output_len_ptr: u32,
    ) -> Result<ReturnErrorCode, TrapReason>;
    fn restore_to(
        _dest_ptr: u32,
        _code_hash_ptr: u32,
        _rent_allowance_ptr: u32,
        _delta_ptr: u32,
        _delta_count: u32,
    ) -> Result<(), TrapReason>;
    fn is_contract(account_ptr: u32) -> Result<u32, TrapReason>;
    fn contains_transient_storage(
        key_ptr: u32,
        key_len: u32,
    ) -> Result<u32, TrapReason>;
    fn minimum_balance(out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason>;
    fn take_transient_storage(
        key_ptr: u32,
        key_len: u32,
        out_ptr: u32,
        out_len_ptr: u32,
    ) -> Result<ReturnErrorCode, TrapReason>;
    fn caller_is_root() -> Result<u32, TrapReason>;
    fn transfer(
        account_ptr: u32,
        _account_len: u32,
        value_ptr: u32,
        _value_len: u32,
    ) -> Result<ReturnErrorCode, TrapReason>;
    fn balance(out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason>;
    fn hash_blake2_256(
        input_ptr: u32,
        input_len: u32,
        output_ptr: u32,
    ) -> Result<(), TrapReason>;
    fn call_chain_extension(
        id: u32,
        input_ptr: u32,
        input_len: u32,
        output_ptr: u32,
        output_len_ptr: u32,
    ) -> Result<u32, TrapReason>;
}

Contains only the latest version of each function.

In reality there are more functions available but they are all obsolete: When a function is updated a new version is added and the old versions stays available as-is. We only list the newest version here. Some functions are available under additional names (aliases) for historic reasons which are omitted here.

If you want an overview of all the functions available to a contact all you need to look at is this trait. It contains only the latest version of each function and no aliases. If you are writing a contract(language) from scratch this is where you should look at.

Required Methods

fn deposit_event( topics_ptr: u32, topics_len: u32, data_ptr: u32, data_len: u32, ) -> Result<(), TrapReason>

Deposit a contract event with the data buffer and optional list of topics. See [pallet_contracts_uapi::HostFn::deposit_event]

Wasm Import Statement

(import "seal0" "deposit_event" (func ...))

fn ecdsa_recover( signature_ptr: u32, message_hash_ptr: u32, output_ptr: u32, ) -> Result<ReturnErrorCode, TrapReason>

Recovers the ECDSA public key from the given message hash and signature. See [pallet_contracts_uapi::HostFn::ecdsa_recover].

Wasm Import Statement

(import "seal0" "ecdsa_recover" (func ...))

fn call_runtime( call_ptr: u32, call_len: u32, ) -> Result<ReturnErrorCode, TrapReason>

Call some dispatchable of the runtime. See [frame_support::traits::call_runtime].

Wasm Import Statement

(import "seal0" "call_runtime" (func ...))

fn clear_storage(key_ptr: u32, key_len: u32) -> Result<u32, TrapReason>

Clear the value at the given key in the contract storage. See [pallet_contracts_uapi::HostFn::clear_storage_v1]

Wasm Import Statement

(import "seal1" "clear_storage" (func ...))

fn sr25519_verify( signature_ptr: u32, pub_key_ptr: u32, message_len: u32, message_ptr: u32, ) -> Result<ReturnErrorCode, TrapReason>

Verify a sr25519 signature See [pallet_contracts_uapi::HostFn::sr25519_verify].

Wasm Import Statement

(import "seal0" "sr25519_verify" (func ...))

fn instantiation_nonce() -> Result<u64, TrapReason>

Returns a nonce that is unique per contract instantiation. See [pallet_contracts_uapi::HostFn::instantiation_nonce].

Wasm Import Statement

(import "seal0" "instantiation_nonce" (func ...))

fn set_transient_storage( key_ptr: u32, key_len: u32, value_ptr: u32, value_len: u32, ) -> Result<u32, TrapReason>

Set the value at the given key in the contract transient storage.

Wasm Import Statement

(import "seal0" "set_transient_storage" (func ...))

Unstable

This function is unstable and it is a subject to change (or removal) in the future. Do not deploy a contract using it to a production chain.

fn caller_is_origin() -> Result<u32, TrapReason>

Checks whether the caller of the current contract is the origin of the whole call stack. See [pallet_contracts_uapi::HostFn::caller_is_origin].

Wasm Import Statement

(import "seal0" "caller_is_origin" (func ...))

fn account_reentrance_count(account_ptr: u32) -> Result<u32, TrapReason>

Returns the number of times specified contract exists on the call stack. Delegated calls are not counted as separate calls. See [pallet_contracts_uapi::HostFn::account_reentrance_count].

Wasm Import Statement

(import "seal0" "account_reentrance_count" (func ...))

Unstable

This function is unstable and it is a subject to change (or removal) in the future. Do not deploy a contract using it to a production chain.

fn get_transient_storage( key_ptr: u32, key_len: u32, out_ptr: u32, out_len_ptr: u32, ) -> Result<ReturnErrorCode, TrapReason>

Retrieve the value under the given key from transient storage.

Wasm Import Statement

(import "seal0" "get_transient_storage" (func ...))

Unstable

This function is unstable and it is a subject to change (or removal) in the future. Do not deploy a contract using it to a production chain.

fn ecdsa_to_eth_address( key_ptr: u32, out_ptr: u32, ) -> Result<ReturnErrorCode, TrapReason>

Calculates Ethereum address from the ECDSA compressed public key and stores See [pallet_contracts_uapi::HostFn::ecdsa_to_eth_address].

Wasm Import Statement

(import "seal0" "ecdsa_to_eth_address" (func ...))

fn own_code_hash(out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason>

Retrieve the code hash of the currently executing contract. See [pallet_contracts_uapi::HostFn::own_code_hash].

Wasm Import Statement

(import "seal0" "own_code_hash" (func ...))

fn noop() -> Result<(), TrapReason>

Noop function used to benchmark the time it takes to execute an empty function.

Wasm Import Statement

(import "seal0" "noop" (func ...))

Unstable

This function is unstable and it is a subject to change (or removal) in the future. Do not deploy a contract using it to a production chain.

fn seal_return( flags: u32, data_ptr: u32, data_len: u32, ) -> Result<(), TrapReason>

Cease contract execution and save a data buffer as a result of the execution. See [pallet_contracts_uapi::HostFn::return_value].

Wasm Import Statement

(import "seal0" "seal_return" (func ...))

fn instantiate( code_hash_ptr: u32, ref_time_limit: u64, proof_size_limit: u64, deposit_ptr: u32, value_ptr: u32, input_data_ptr: u32, input_data_len: u32, address_ptr: u32, address_len_ptr: u32, output_ptr: u32, output_len_ptr: u32, salt_ptr: u32, salt_len: u32, ) -> Result<ReturnErrorCode, TrapReason>

Instantiate a contract with the specified code hash. See [pallet_contracts_uapi::HostFn::instantiate_v2].

Wasm Import Statement

(import "seal2" "instantiate" (func ...))

fn call( flags: u32, callee_ptr: u32, ref_time_limit: u64, proof_size_limit: u64, deposit_ptr: u32, value_ptr: u32, input_data_ptr: u32, input_data_len: u32, output_ptr: u32, output_len_ptr: u32, ) -> Result<ReturnErrorCode, TrapReason>

Make a call to another contract. See [pallet_contracts_uapi::HostFn::call_v2].

Wasm Import Statement

(import "seal2" "call" (func ...))

fn address(out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason>

Stores the address of the current contract into the supplied buffer. See [pallet_contracts_uapi::HostFn::address].

Wasm Import Statement

(import "seal0" "address" (func ...))

fn tombstone_deposit(out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason>

Deprecated

This function is deprecated and will be removed in future versions. No new code or contracts with this API can be deployed. Stores the tombstone deposit into the supplied buffer.

The value is stored to linear memory at the address pointed to by out_ptr. out_len_ptr must point to a u32 value that describes the available space at out_ptr. This call overwrites it with the size of the value. If the available space at out_ptr is less than the size of the value a trap is triggered.

Note

There is no longer a tombstone deposit. This function always returns 0.

Wasm Import Statement

(import "seal0" "tombstone_deposit" (func ...))

fn input(out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason>

Stores the input passed by the caller into the supplied buffer. See [pallet_contracts_uapi::HostFn::input].

Wasm Import Statement

(import "seal0" "input" (func ...))

fn rent_allowance(out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason>

Deprecated

This function is deprecated and will be removed in future versions. No new code or contracts with this API can be deployed. Was used to store the rent allowance into the supplied buffer.

Note

The state rent functionality was removed. This is stub only exists for backwards compatibility.

Wasm Import Statement

(import "seal0" "rent_allowance" (func ...))

fn hash_sha2_256( input_ptr: u32, input_len: u32, output_ptr: u32, ) -> Result<(), TrapReason>

Computes the SHA2 256-bit hash on the given input buffer. See [pallet_contracts_uapi::HostFn::hash_sha2_256].

Wasm Import Statement

(import "seal0" "hash_sha2_256" (func ...))

fn hash_keccak_256( input_ptr: u32, input_len: u32, output_ptr: u32, ) -> Result<(), TrapReason>

Computes the KECCAK 256-bit hash on the given input buffer. See [pallet_contracts_uapi::HostFn::hash_keccak_256].

Wasm Import Statement

(import "seal0" "hash_keccak_256" (func ...))

fn weight_to_fee( ref_time_limit: u64, proof_size_limit: u64, out_ptr: u32, out_len_ptr: u32, ) -> Result<(), TrapReason>

Stores the price for the specified amount of weight into the supplied buffer. See [pallet_contracts_uapi::HostFn::weight_to_fee_v1].

Wasm Import Statement

(import "seal1" "weight_to_fee" (func ...))

Unstable

This function is unstable and it is a subject to change (or removal) in the future. Do not deploy a contract using it to a production chain.

fn contains_storage(key_ptr: u32, key_len: u32) -> Result<u32, TrapReason>

Checks whether there is a value stored under the given key. See [pallet_contracts_uapi::HostFn::contains_storage_v1]

Wasm Import Statement

(import "seal1" "contains_storage" (func ...))

fn set_code_hash(code_hash_ptr: u32) -> Result<ReturnErrorCode, TrapReason>

Replace the contract code at the specified address with new code. See [pallet_contracts_uapi::HostFn::set_code_hash].

Wasm Import Statement

(import "seal0" "set_code_hash" (func ...))

fn lock_delegate_dependency(code_hash_ptr: u32) -> Result<(), TrapReason>

Adds a new delegate dependency to the contract. See [pallet_contracts_uapi::HostFn::lock_delegate_dependency].

Wasm Import Statement

(import "seal0" "lock_delegate_dependency" (func ...))

fn hash_blake2_128( input_ptr: u32, input_len: u32, output_ptr: u32, ) -> Result<(), TrapReason>

Computes the BLAKE2 128-bit hash on the given input buffer. See [pallet_contracts_uapi::HostFn::hash_blake2_128].

Wasm Import Statement

(import "seal0" "hash_blake2_128" (func ...))

fn unlock_delegate_dependency(code_hash_ptr: u32) -> Result<(), TrapReason>

Removes the delegate dependency from the contract. see [pallet_contracts_uapi::HostFn::unlock_delegate_dependency].

Wasm Import Statement

(import "seal0" "unlock_delegate_dependency" (func ...))

fn value_transferred(out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason>

Stores the value transferred along with this call/instantiate into the supplied buffer. See [pallet_contracts_uapi::HostFn::value_transferred].

Wasm Import Statement

(import "seal0" "value_transferred" (func ...))

fn take_storage( key_ptr: u32, key_len: u32, out_ptr: u32, out_len_ptr: u32, ) -> Result<ReturnErrorCode, TrapReason>

Retrieve and remove the value under the given key from storage. See [pallet_contracts_uapi::HostFn::take_storage]

Wasm Import Statement

(import "seal0" "take_storage" (func ...))

fn caller(out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason>

Stores the address of the caller into the supplied buffer. See [pallet_contracts_uapi::HostFn::caller].

Wasm Import Statement

(import "seal0" "caller" (func ...))

fn xcm_send( dest_ptr: u32, msg_ptr: u32, msg_len: u32, output_ptr: u32, ) -> Result<ReturnErrorCode, TrapReason>

Send an XCM program from the contract to the specified destination. See [pallet_contracts_uapi::HostFn::send_xcm].

Wasm Import Statement

(import "seal0" "xcm_send" (func ...))

fn reentrance_count() -> Result<u32, TrapReason>

Returns the number of times the currently executing contract exists on the call stack in addition to the calling instance. See [pallet_contracts_uapi::HostFn::reentrance_count].

Wasm Import Statement

(import "seal0" "reentrance_count" (func ...))

Unstable

This function is unstable and it is a subject to change (or removal) in the future. Do not deploy a contract using it to a production chain.

fn set_rent_allowance(_value_ptr: u32) -> Result<(), TrapReason>

Deprecated

This function is deprecated and will be removed in future versions. No new code or contracts with this API can be deployed. Was used to set rent allowance of the contract.

Note

The state rent functionality was removed. This is stub only exists for backwards compatibility.

Wasm Import Statement

(import "seal1" "set_rent_allowance" (func ...))

fn random( subject_ptr: u32, subject_len: u32, out_ptr: u32, out_len_ptr: u32, ) -> Result<(), TrapReason>

Deprecated

This function is deprecated and will be removed in future versions. No new code or contracts with this API can be deployed. Stores a random number for the current block and the given subject into the supplied buffer.

The value is stored to linear memory at the address pointed to by out_ptr. out_len_ptr must point to a u32 value that describes the available space at out_ptr. This call overwrites it with the size of the value. If the available space at out_ptr is less than the size of the value a trap is triggered.

The data is encoded as (T::Hash, frame_system::pallet_prelude::BlockNumberFor::).

Changes from v0

In addition to the seed it returns the block number since which it was determinable by chain observers.

Note

The returned seed should only be used to distinguish commitments made before the returned block number. If the block number is too early (i.e. commitments were made afterwards), then ensure no further commitments may be made and repeatedly call this on later blocks until the block number returned is later than the latest commitment.

Wasm Import Statement

(import "seal1" "random" (func ...))

fn code_hash( account_ptr: u32, out_ptr: u32, out_len_ptr: u32, ) -> Result<ReturnErrorCode, TrapReason>

Retrieve the code hash for a specified contract address. See [pallet_contracts_uapi::HostFn::code_hash].

Wasm Import Statement

(import "seal0" "code_hash" (func ...))

fn get_storage( key_ptr: u32, key_len: u32, out_ptr: u32, out_len_ptr: u32, ) -> Result<ReturnErrorCode, TrapReason>

Retrieve the value under the given key from storage. See [pallet_contracts_uapi::HostFn::get_storage_v1]

Wasm Import Statement

(import "seal1" "get_storage" (func ...))

fn now(out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason>

Load the latest block timestamp into the supplied buffer See [pallet_contracts_uapi::HostFn::now].

Wasm Import Statement

(import "seal0" "now" (func ...))

fn xcm_execute( msg_ptr: u32, msg_len: u32, ) -> Result<ReturnErrorCode, TrapReason>

Execute an XCM program locally, using the contract’s address as the origin. See [pallet_contracts_uapi::HostFn::execute_xcm].

Wasm Import Statement

(import "seal0" "xcm_execute" (func ...))

fn terminate(beneficiary_ptr: u32) -> Result<(), TrapReason>

Remove the calling account and transfer remaining free balance. See [pallet_contracts_uapi::HostFn::terminate_v1].

Wasm Import Statement

(import "seal1" "terminate" (func ...))

fn gas_left(out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason>

Stores the amount of weight left into the supplied buffer. See [pallet_contracts_uapi::HostFn::gas_left_v1].

Wasm Import Statement

(import "seal1" "gas_left" (func ...))

Unstable

This function is unstable and it is a subject to change (or removal) in the future. Do not deploy a contract using it to a production chain.

fn set_storage( key_ptr: u32, key_len: u32, value_ptr: u32, value_len: u32, ) -> Result<u32, TrapReason>

Set the value at the given key in the contract storage. See [pallet_contracts_uapi::HostFn::set_storage_v2]

Wasm Import Statement

(import "seal2" "set_storage" (func ...))

fn clear_transient_storage( key_ptr: u32, key_len: u32, ) -> Result<u32, TrapReason>

Clear the value at the given key in the contract storage.

Wasm Import Statement

(import "seal0" "clear_transient_storage" (func ...))

Unstable

This function is unstable and it is a subject to change (or removal) in the future. Do not deploy a contract using it to a production chain.

fn block_number(out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason>

Stores the current block number of the current contract into the supplied buffer. See [pallet_contracts_uapi::HostFn::block_number].

Wasm Import Statement

(import "seal0" "block_number" (func ...))

fn debug_message( str_ptr: u32, str_len: u32, ) -> Result<ReturnErrorCode, TrapReason>

Emit a custom debug message.

No newlines are added to the supplied message. Specifying invalid UTF-8 just drops the message with no trap.

This is a no-op if debug message recording is disabled which is always the case when the code is executing on-chain. The message is interpreted as UTF-8 and appended to the debug buffer which is then supplied to the calling RPC client.

Note

Even though no action is taken when debug message recording is disabled there is still a non trivial overhead (and weight cost) associated with calling this function. Contract languages should remove calls to this function (either at runtime or compile time) when not being executed as an RPC. For example, they could allow users to disable logging through compile time flags (cargo features) for on-chain deployment. Additionally, the return value of this function can be cached in order to prevent further calls at runtime.

Wasm Import Statement

(import "seal0" "debug_message" (func ...))

fn delegate_call( flags: u32, code_hash_ptr: u32, input_data_ptr: u32, input_data_len: u32, output_ptr: u32, output_len_ptr: u32, ) -> Result<ReturnErrorCode, TrapReason>

Execute code in the context (storage, caller, value) of the current contract. See [pallet_contracts_uapi::HostFn::delegate_call].

Wasm Import Statement

(import "seal0" "delegate_call" (func ...))

fn restore_to( _dest_ptr: u32, _code_hash_ptr: u32, _rent_allowance_ptr: u32, _delta_ptr: u32, _delta_count: u32, ) -> Result<(), TrapReason>

Deprecated

This function is deprecated and will be removed in future versions. No new code or contracts with this API can be deployed. Was used to restore the given destination contract sacrificing the caller.

Note

The state rent functionality was removed. This is stub only exists for backwards compatibility

Wasm Import Statement

(import "seal1" "restore_to" (func ...))

fn is_contract(account_ptr: u32) -> Result<u32, TrapReason>

Checks whether a specified address belongs to a contract. See [pallet_contracts_uapi::HostFn::is_contract].

Wasm Import Statement

(import "seal0" "is_contract" (func ...))

fn contains_transient_storage( key_ptr: u32, key_len: u32, ) -> Result<u32, TrapReason>

Checks whether there is a value stored under the given key in transient storage.

Wasm Import Statement

(import "seal0" "contains_transient_storage" (func ...))

Unstable

This function is unstable and it is a subject to change (or removal) in the future. Do not deploy a contract using it to a production chain.

fn minimum_balance(out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason>

Stores the minimum balance (a.k.a. existential deposit) into the supplied buffer. See [pallet_contracts_uapi::HostFn::minimum_balance].

Wasm Import Statement

(import "seal0" "minimum_balance" (func ...))

fn take_transient_storage( key_ptr: u32, key_len: u32, out_ptr: u32, out_len_ptr: u32, ) -> Result<ReturnErrorCode, TrapReason>

Retrieve and remove the value under the given key from transient storage.

Wasm Import Statement

(import "seal0" "take_transient_storage" (func ...))

Unstable

This function is unstable and it is a subject to change (or removal) in the future. Do not deploy a contract using it to a production chain.

fn caller_is_root() -> Result<u32, TrapReason>

Checks whether the caller of the current contract is root. See [pallet_contracts_uapi::HostFn::caller_is_root].

Wasm Import Statement

(import "seal0" "caller_is_root" (func ...))

fn transfer( account_ptr: u32, _account_len: u32, value_ptr: u32, _value_len: u32, ) -> Result<ReturnErrorCode, TrapReason>

Transfer some value to another account. See [pallet_contracts_uapi::HostFn::transfer].

Wasm Import Statement

(import "seal0" "transfer" (func ...))

fn balance(out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason>

Stores the free balance of the current account into the supplied buffer. See [pallet_contracts_uapi::HostFn::balance].

Wasm Import Statement

(import "seal0" "balance" (func ...))

fn hash_blake2_256( input_ptr: u32, input_len: u32, output_ptr: u32, ) -> Result<(), TrapReason>

Computes the BLAKE2 256-bit hash on the given input buffer. See [pallet_contracts_uapi::HostFn::hash_blake2_256].

Wasm Import Statement

(import "seal0" "hash_blake2_256" (func ...))

fn call_chain_extension( id: u32, input_ptr: u32, input_len: u32, output_ptr: u32, output_len_ptr: u32, ) -> Result<u32, TrapReason>

Call into the chain extension provided by the chain if any. See [pallet_contracts_uapi::HostFn::call_chain_extension].

Wasm Import Statement

(import "seal0" "call_chain_extension" (func ...))

Object Safety

This trait is not object safe.

Implementors