Trait HostFn

Source

pub trait HostFn: Sealed {
Show 61 methods    // Required methods
    fn account_reentrance_count(account: &[u8]) -> u32;
    fn address(output: &mut &mut [u8]);
    fn lock_delegate_dependency(code_hash: &[u8]);
    fn balance(output: &mut &mut [u8]);
    fn block_number(output: &mut &mut [u8]);
    fn call(
        callee: &[u8],
        gas: u64,
        value: &[u8],
        input_data: &[u8],
        output: Option<&mut &mut [u8]>,
    ) -> Result<(), ReturnErrorCode>;
    fn call_v1(
        flags: CallFlags,
        callee: &[u8],
        gas: u64,
        value: &[u8],
        input_data: &[u8],
        output: Option<&mut &mut [u8]>,
    ) -> Result<(), ReturnErrorCode>;
    fn call_v2(
        flags: CallFlags,
        callee: &[u8],
        ref_time_limit: u64,
        proof_size_limit: u64,
        deposit: Option<&[u8]>,
        value: &[u8],
        input_data: &[u8],
        output: Option<&mut &mut [u8]>,
    ) -> Result<(), ReturnErrorCode>;
    fn call_chain_extension(
        func_id: u32,
        input: &[u8],
        output: Option<&mut &mut [u8]>,
    ) -> u32;
    fn call_runtime(call: &[u8]) -> Result<(), ReturnErrorCode>;
    fn caller(output: &mut &mut [u8]);
    fn caller_is_origin() -> bool;
    fn caller_is_root() -> u32;
    fn clear_storage(key: &[u8]);
    fn clear_storage_v1(key: &[u8]) -> Option<u32>;
    fn clear_transient_storage(key: &[u8]) -> Option<u32>;
    fn code_hash(
        account_id: &[u8],
        output: &mut [u8],
    ) -> Result<(), ReturnErrorCode>;
    fn contains_storage(key: &[u8]) -> Option<u32>;
    fn contains_storage_v1(key: &[u8]) -> Option<u32>;
    fn contains_transient_storage(key: &[u8]) -> Option<u32>;
    fn debug_message(str: &[u8]) -> Result<(), ReturnErrorCode>;
    fn delegate_call(
        flags: CallFlags,
        code_hash: &[u8],
        input_data: &[u8],
        output: Option<&mut &mut [u8]>,
    ) -> Result<(), ReturnErrorCode>;
    fn deposit_event(topics: &[u8], data: &[u8]);
    fn ecdsa_recover(
        signature: &[u8; 65],
        message_hash: &[u8; 32],
        output: &mut [u8; 33],
    ) -> Result<(), ReturnErrorCode>;
    fn ecdsa_to_eth_address(
        pubkey: &[u8; 33],
        output: &mut [u8; 20],
    ) -> Result<(), ReturnErrorCode>;
    fn gas_left(out: &mut &mut [u8]);
    fn gas_left_v1(output: &mut &mut [u8]);
    fn get_storage(
        key: &[u8],
        output: &mut &mut [u8],
    ) -> Result<(), ReturnErrorCode>;
    fn get_storage_v1(
        key: &[u8],
        output: &mut &mut [u8],
    ) -> Result<(), ReturnErrorCode>;
    fn get_transient_storage(
        key: &[u8],
        output: &mut &mut [u8],
    ) -> Result<(), ReturnErrorCode>;
    fn hash_sha2_256(input: &[u8], output: &mut [u8; 32]);
    fn hash_keccak_256(input: &[u8], output: &mut [u8; 32]);
    fn hash_blake2_256(input: &[u8], output: &mut [u8; 32]);
    fn hash_blake2_128(input: &[u8], output: &mut [u8; 16]);
    fn input(output: &mut &mut [u8]);
    fn instantiate_v1(
        code_hash: &[u8],
        gas: u64,
        value: &[u8],
        input: &[u8],
        address: Option<&mut &mut [u8]>,
        output: Option<&mut &mut [u8]>,
        salt: &[u8],
    ) -> Result<(), ReturnErrorCode>;
    fn instantiate_v2(
        code_hash: &[u8],
        ref_time_limit: u64,
        proof_size_limit: u64,
        deposit: Option<&[u8]>,
        value: &[u8],
        input: &[u8],
        address: Option<&mut &mut [u8]>,
        output: Option<&mut &mut [u8]>,
        salt: &[u8],
    ) -> Result<(), ReturnErrorCode>;
    fn instantiation_nonce() -> u64;
    fn is_contract(account_id: &[u8]) -> bool;
    fn minimum_balance(output: &mut &mut [u8]);
    fn own_code_hash(output: &mut [u8]);
    fn now(output: &mut &mut [u8]);
    fn reentrance_count() -> u32;
    fn unlock_delegate_dependency(code_hash: &[u8]);
    fn return_value(flags: ReturnFlags, return_value: &[u8]) -> !;
    fn set_code_hash(code_hash: &[u8]) -> Result<(), ReturnErrorCode>;
    fn set_storage(key: &[u8], value: &[u8]);
    fn set_storage_v1(key: &[u8], value: &[u8]) -> Option<u32>;
    fn set_storage_v2(key: &[u8], value: &[u8]) -> Option<u32>;
    fn set_transient_storage(key: &[u8], value: &[u8]) -> Option<u32>;
    fn sr25519_verify(
        signature: &[u8; 64],
        message: &[u8],
        pub_key: &[u8; 32],
    ) -> Result<(), ReturnErrorCode>;
    fn take_storage(
        key: &[u8],
        output: &mut &mut [u8],
    ) -> Result<(), ReturnErrorCode>;
    fn take_transient_storage(
        key: &[u8],
        output: &mut &mut [u8],
    ) -> Result<(), ReturnErrorCode>;
    fn transfer(account_id: &[u8], value: &[u8]) -> Result<(), ReturnErrorCode>;
    fn terminate(beneficiary: &[u8]) -> !;
    fn terminate_v1(beneficiary: &[u8]) -> !;
    fn value_transferred(output: &mut &mut [u8]);
    fn weight_to_fee(gas: u64, output: &mut &mut [u8]);
    fn weight_to_fee_v1(
        ref_time_limit: u64,
        proof_size_limit: u64,
        output: &mut &mut [u8],
    );
    fn xcm_execute(msg: &[u8]) -> Result<(), ReturnErrorCode>;
    fn xcm_send(
        dest: &[u8],
        msg: &[u8],
        output: &mut [u8; 32],
    ) -> Result<(), ReturnErrorCode>;
}

Expand description

Defines all the host apis implemented by the wasm vm.

Required Methods§

Source

fn account_reentrance_count(account: &[u8]) -> u32

👎Deprecated: Unstable function. Behaviour can change without further notice. Use only for testing.

Returns the number of times specified contract exists on the call stack. Delegated calls are not counted as separate calls.

§Parameters

account: The contract address. Should be decodable as an T::AccountId. Traps otherwise.

§Return

Returns the number of times specified contract exists on the call stack.

Source

fn address(output: &mut &mut [u8])

Stores the address of the current contract into the supplied buffer.

If the available space in output is less than the size of the value a trap is triggered.

§Parameters

output: A reference to the output data buffer to write the address.

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fn lock_delegate_dependency(code_hash: &[u8])

Lock a new delegate dependency to the contract.

Traps if the maximum number of delegate_dependencies is reached or if the delegate dependency already exists.

§Parameters

code_hash: The code hash of the dependency. Should be decodable as an T::Hash. Traps otherwise.

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fn balance(output: &mut &mut [u8])

Stores the free balance of the current account into the supplied buffer.

If the available space in output is less than the size of the value a trap is triggered.

§Parameters

output: A reference to the output data buffer to write the balance.

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fn block_number(output: &mut &mut [u8])

Stores the current block number of the current contract into the supplied buffer.

If the available space in output is less than the size of the value a trap is triggered.

§Parameters

output: A reference to the output data buffer to write the block number.

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fn call( callee: &[u8], gas: u64, value: &[u8], input_data: &[u8], output: Option<&mut &mut [u8]>, ) -> Result<(), ReturnErrorCode>

👎Deprecated: Deprecated, use newer version instead

Make a call to another contract.

This is equivalent to calling the newer version of this function with flags set to CallFlags::ALLOW_REENTRY. See the newer version for documentation.

Source

fn call_v1( flags: CallFlags, callee: &[u8], gas: u64, value: &[u8], input_data: &[u8], output: Option<&mut &mut [u8]>, ) -> Result<(), ReturnErrorCode>

👎Deprecated: Deprecated, use newer version instead

Make a call to another contract.

Equivalent to the newer Self::call_v2 version but works with ref_time Weight only

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fn call_v2( flags: CallFlags, callee: &[u8], ref_time_limit: u64, proof_size_limit: u64, deposit: Option<&[u8]>, value: &[u8], input_data: &[u8], output: Option<&mut &mut [u8]>, ) -> Result<(), ReturnErrorCode>

Call (possibly transferring some amount of funds) into the specified account.

§Parameters

flags: See CallFlags for a documentation of the supported flags.
callee: The address of the callee. Should be decodable as an T::AccountId. Traps otherwise.
ref_time_limit: how much ref_time Weight to devote to the execution.
proof_size_limit: how much proof_size Weight to devote to the execution.
deposit: The storage deposit limit for instantiation. Should be decodable as a Option<T::Balance>. Traps otherwise. Passing None means setting no specific limit for the call, which implies storage usage up to the limit of the parent call.
value: The value to transfer into the contract. Should be decodable as a T::Balance. Traps otherwise.
input: The input data buffer used to call the contract.
output: A reference to the output data buffer to write the call output buffer. If None is provided then the output buffer is not copied.

§Errors

An error means that the call wasn’t successful output buffer is returned unless stated otherwise.

CalleeReverted: Output buffer is returned.
CalleeTrapped
TransferFailed
NotCallable

Source

fn call_chain_extension( func_id: u32, input: &[u8], output: Option<&mut &mut [u8]>, ) -> u32

Call into the chain extension provided by the chain if any.

Handling of the input values is up to the specific chain extension and so is the return value. The extension can decide to use the inputs as primitive inputs or as in/out arguments by interpreting them as pointers. Any caller of this function must therefore coordinate with the chain that it targets.

§Note

If no chain extension exists the contract will trap with the NoChainExtension module error.

§Parameters

func_id: The function id of the chain extension.
input: The input data buffer.
output: A reference to the output data buffer to write the call output buffer. If None is provided then the output buffer is not copied.

§Return

The chain extension returned value, if executed successfully.

Source

fn call_runtime(call: &[u8]) -> Result<(), ReturnErrorCode>

Call some dispatchable of the runtime.

§Parameters

call: The call data.

§Return

Returns Error::Success when the dispatchable was successfully executed and returned Ok. When the dispatchable was executed but returned an error Error::CallRuntimeFailed is returned. The full error is not provided because it is not guaranteed to be stable.

§Comparison with `ChainExtension`

Just as a chain extension this API allows the runtime to extend the functionality of contracts. While making use of this function is generally easier it cannot be used in all cases. Consider writing a chain extension if you need to do perform one of the following tasks:

Return data.
Provide functionality exclusively to contracts.
Provide custom weights.
Avoid the need to keep the Call data structure stable.

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fn caller(output: &mut &mut [u8])

Stores the address of the caller into the supplied buffer.

If the available space in output is less than the size of the value a trap is triggered.

If this is a top-level call (i.e. initiated by an extrinsic) the origin address of the extrinsic will be returned. Otherwise, if this call is initiated by another contract then the address of the contract will be returned.

If there is no address associated with the caller (e.g. because the caller is root) then it traps with BadOrigin.

§Parameters

output: A reference to the output data buffer to write the caller address.

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fn caller_is_origin() -> bool

Checks whether the caller of the current contract is the origin of the whole call stack.

Prefer this over is_contract() when checking whether your contract is being called by a contract or a plain account. The reason is that it performs better since it does not need to do any storage lookups.

§Return

A return value of true indicates that this contract is being called by a plain account and false indicates that the caller is another contract.

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fn caller_is_root() -> u32

Checks whether the caller of the current contract is root.

Note that only the origin of the call stack can be root. Hence this function returning true implies that the contract is being called by the origin.

A return value of true indicates that this contract is being called by a root origin, and false indicates that the caller is a signed origin.

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fn clear_storage(key: &[u8])

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

Equivalent to the newer Self::clear_storage_v1 version with the exception of the return type. Still a valid thing to call when not interested in the return value.

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fn clear_storage_v1(key: &[u8]) -> Option<u32>

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

§Parameters

key: The storage key.

§Return

Returns the size of the pre-existing value at the specified key if any.

Source

fn clear_transient_storage(key: &[u8]) -> Option<u32>

👎Deprecated: Unstable function. Behaviour can change without further notice. Use only for testing.

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

§Parameters

key: The storage key.

§Return

Returns the size of the pre-existing value at the specified key if any.

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fn code_hash( account_id: &[u8], output: &mut [u8], ) -> Result<(), ReturnErrorCode>

Retrieve the code hash for a specified contract address.

§Parameters

account_id: The address of the contract.Should be decodable as an T::AccountId. Traps otherwise.
output: A reference to the output data buffer to write the code hash.

§Errors

CodeNotFound

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fn contains_storage(key: &[u8]) -> Option<u32>

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

This version is to be used with a fixed sized storage key. For runtimes supporting transparent hashing, please use the newer version of this function.

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fn contains_storage_v1(key: &[u8]) -> Option<u32>

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

The key length must not exceed the maximum defined by the contracts module parameter.

§Parameters

key: The storage key.

§Return

Returns the size of the pre-existing value at the specified key if any.

Source

fn contains_transient_storage(key: &[u8]) -> Option<u32>

👎Deprecated: Unstable function. Behaviour can change without further notice. Use only for testing.

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

The key length must not exceed the maximum defined by the contracts module parameter.

§Parameters

key: The storage key.

§Return

Returns the size of the pre-existing value at the specified key if any.

Source

fn debug_message(str: &[u8]) -> Result<(), ReturnErrorCode>

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.

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fn delegate_call( flags: CallFlags, code_hash: &[u8], input_data: &[u8], output: Option<&mut &mut [u8]>, ) -> Result<(), ReturnErrorCode>

Execute code in the context (storage, caller, value) of the current contract.

Reentrancy protection is always disabled since the callee is allowed to modify the callers storage. This makes going through a reentrancy attack unnecessary for the callee when it wants to exploit the caller.

§Parameters

flags: See CallFlags for a documentation of the supported flags.
code_hash: The hash of the code to be executed.
input: The input data buffer used to call the contract.
output: A reference to the output data buffer to write the call output buffer. If None is provided then the output buffer is not copied.

§Errors

An error means that the call wasn’t successful and no output buffer is returned unless stated otherwise.

CalleeReverted: Output buffer is returned.
CalleeTrapped
CodeNotFound

Source

fn deposit_event(topics: &[u8], data: &[u8])

Deposit a contract event with the data buffer and optional list of topics. There is a limit on the maximum number of topics specified by event_topics.

There should not be any duplicates in topics.

§Parameters

topics: The topics list encoded as Vec<T::Hash>. It can’t contain duplicates.

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fn ecdsa_recover( signature: &[u8; 65], message_hash: &[u8; 32], output: &mut [u8; 33], ) -> Result<(), ReturnErrorCode>

Recovers the ECDSA public key from the given message hash and signature.

Writes the public key into the given output buffer. Assumes the secp256k1 curve.

§Parameters

signature: The signature bytes.
message_hash: The message hash bytes.
output: A reference to the output data buffer to write the public key.

§Errors

EcdsaRecoveryFailed

Source

fn ecdsa_to_eth_address( pubkey: &[u8; 33], output: &mut [u8; 20], ) -> Result<(), ReturnErrorCode>

Calculates Ethereum address from the ECDSA compressed public key and stores it into the supplied buffer.

§Parameters

pubkey: The public key bytes.
output: A reference to the output data buffer to write the address.

§Errors

EcdsaRecoveryFailed

Source

fn gas_left(out: &mut &mut [u8])

Stores the weight left into the supplied buffer.

Equivalent to the newer Self::gas_left_v1 version but works with ref_time Weight only.

Source

fn gas_left_v1(output: &mut &mut [u8])

👎Deprecated: Unstable function. Behaviour can change without further notice. Use only for testing.

Stores the amount of weight left into the supplied buffer. The data is encoded as Weight.

If the available space in output is less than the size of the value a trap is triggered.

§Parameters

output: A reference to the output data buffer to write the weight left.

Source

fn get_storage( key: &[u8], output: &mut &mut [u8], ) -> Result<(), ReturnErrorCode>

Retrieve the value under the given key from storage.

This version is to be used with a fixed sized storage key. For runtimes supporting transparent hashing, please use the newer version of this function.

Source

fn get_storage_v1( key: &[u8], output: &mut &mut [u8], ) -> Result<(), ReturnErrorCode>

Retrieve the value under the given key from storage.

The key length must not exceed the maximum defined by the contracts module parameter.

§Parameters

key: The storage key.
output: A reference to the output data buffer to write the storage entry.

§Errors

KeyNotFound

Source

fn get_transient_storage( key: &[u8], output: &mut &mut [u8], ) -> Result<(), ReturnErrorCode>

👎Deprecated: Unstable function. Behaviour can change without further notice. Use only for testing.

Retrieve the value under the given key from transient storage.

The key length must not exceed the maximum defined by the contracts module parameter.

§Parameters

key: The storage key.
output: A reference to the output data buffer to write the storage entry.

§Errors

KeyNotFound

Source

fn hash_sha2_256(input: &[u8], output: &mut [u8; 32])

Computes the sha2_256 32-bit hash on the given input buffer.

§Notes

The input and output buffer may overlap.
The output buffer is expected to hold at least 32 bits.
It is the callers responsibility to provide an output buffer that is large enough to hold the expected amount of bytes returned by the hash function.

§Parameters

input: The input data buffer.
output: The output buffer to write the hash result to.

Source

fn hash_keccak_256(input: &[u8], output: &mut [u8; 32])

Computes the keccak_256 32-bit hash on the given input buffer.

§Notes

The input and output buffer may overlap.
The output buffer is expected to hold at least 32 bits.
It is the callers responsibility to provide an output buffer that is large enough to hold the expected amount of bytes returned by the hash function.

§Parameters

input: The input data buffer.
output: The output buffer to write the hash result to.

Source

fn hash_blake2_256(input: &[u8], output: &mut [u8; 32])

Computes the blake2_256 32-bit hash on the given input buffer.

§Notes

The input and output buffer may overlap.
The output buffer is expected to hold at least 32 bits.
It is the callers responsibility to provide an output buffer that is large enough to hold the expected amount of bytes returned by the hash function.

§Parameters

input: The input data buffer.
output: The output buffer to write the hash result to.

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fn hash_blake2_128(input: &[u8], output: &mut [u8; 16])

Computes the blake2_128 16-bit hash on the given input buffer.

§Notes

The input and output buffer may overlap.
The output buffer is expected to hold at least 16 bits.
It is the callers responsibility to provide an output buffer that is large enough to hold the expected amount of bytes returned by the hash function.

§Parameters

input: The input data buffer.
output: The output buffer to write the hash result to.

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fn input(output: &mut &mut [u8])

Stores the input passed by the caller into the supplied buffer.

§Note

This function traps if:

the input is larger than the available space.
the input was previously forwarded by a call().

§Parameters

output: A reference to the output data buffer to write the input data.

Source

fn instantiate_v1( code_hash: &[u8], gas: u64, value: &[u8], input: &[u8], address: Option<&mut &mut [u8]>, output: Option<&mut &mut [u8]>, salt: &[u8], ) -> Result<(), ReturnErrorCode>

👎Deprecated: Deprecated, use newer version instead

Instantiate a contract with the specified code hash.

Equivalent to the newer Self::instantiate_v2 version but works with ref_time Weight only.

Source

fn instantiate_v2( code_hash: &[u8], ref_time_limit: u64, proof_size_limit: u64, deposit: Option<&[u8]>, value: &[u8], input: &[u8], address: Option<&mut &mut [u8]>, output: Option<&mut &mut [u8]>, salt: &[u8], ) -> Result<(), ReturnErrorCode>

Instantiate a contract with the specified code hash.

This function creates an account and executes the constructor defined in the code specified by the code hash.

§Parameters

code_hash: The hash of the code to be instantiated.
ref_time_limit: how much ref_time Weight to devote to the execution.
proof_size_limit: how much proof_size Weight to devote to the execution.
deposit: The storage deposit limit for instantiation. Should be decodable as a Option<T::Balance>. Traps otherwise. Passing None means setting no specific limit for the call, which implies storage usage up to the limit of the parent call.
value: The value to transfer into the contract. Should be decodable as a T::Balance. Traps otherwise.
input: The input data buffer.
address: A reference to the address buffer to write the address of the contract. If None is provided then the output buffer is not copied.
output: A reference to the return value buffer to write the constructor output buffer. If None is provided then the output buffer is not copied.
salt: The salt bytes to use for this instantiation.

§Errors

Please consult the ReturnErrorCode enum declaration for more information on those errors. Here we only note things specific to this function.

An error means that the account wasn’t created and no address or output buffer is returned unless stated otherwise.

CalleeReverted: Output buffer is returned.
CalleeTrapped
TransferFailed
CodeNotFound

Source

fn instantiation_nonce() -> u64

Returns a nonce that is unique per contract instantiation.

The nonce is incremented for each successful contract instantiation. This is a sensible default salt for contract instantiations.

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fn is_contract(account_id: &[u8]) -> bool

Checks whether a specified address belongs to a contract.

§Parameters

account_id: The address to check. Should be decodable as an T::AccountId. Traps otherwise.

§Return

Returns true if the address belongs to a contract.

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fn minimum_balance(output: &mut &mut [u8])

Stores the minimum balance (a.k.a. existential deposit) into the supplied buffer. The data is encoded as T::Balance.

If the available space in output is less than the size of the value a trap is triggered.

§Parameters

output: A reference to the output data buffer to write the minimum balance.

Source

fn own_code_hash(output: &mut [u8])

Retrieve the code hash of the currently executing contract.

§Parameters

output: A reference to the output data buffer to write the code hash.

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fn now(output: &mut &mut [u8])

Load the latest block timestamp into the supplied buffer

If the available space in output is less than the size of the value a trap is triggered.

§Parameters

output: A reference to the output data buffer to write the timestamp.

Source

fn reentrance_count() -> u32

👎Deprecated: Unstable function. Behaviour can change without further notice. Use only for testing.

Returns the number of times the currently executing contract exists on the call stack in addition to the calling instance.

§Return

Returns 0 when there is no reentrancy.

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fn unlock_delegate_dependency(code_hash: &[u8])

Removes the delegate dependency from the contract.

Traps if the delegate dependency does not exist.

§Parameters

code_hash: The code hash of the dependency. Should be decodable as an T::Hash. Traps otherwise.

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fn return_value(flags: ReturnFlags, return_value: &[u8]) -> !

Cease contract execution and save a data buffer as a result of the execution.

This function never returns as it stops execution of the caller. This is the only way to return a data buffer to the caller. Returning from execution without calling this function is equivalent to calling:

return_value(ReturnFlags::empty(), &[])

Using an unnamed non empty ReturnFlags triggers a trap.

§Parameters

flags: Flag used to signal special return conditions to the supervisor. See ReturnFlags for a documentation of the supported flags.
return_value: The return value buffer.

Source

fn set_code_hash(code_hash: &[u8]) -> Result<(), ReturnErrorCode>

Replace the contract code at the specified address with new code.

§Note

There are a couple of important considerations which must be taken into account when using this API:

The storage at the code address will remain untouched. This means that contract developers must ensure that the storage layout of the new code is compatible with that of the old code.
Contracts using this API can’t be assumed as having deterministic addresses. Said another way, when using this API you lose the guarantee that an address always identifies a specific code hash.
If a contract calls into itself after changing its code the new call would use the new code. However, if the original caller panics after returning from the sub call it would revert the changes made by set_code_hash() and the next caller would use the old code.

§Parameters

code_hash: The hash of the new code. Should be decodable as an T::Hash. Traps otherwise.

§Errors

CodeNotFound

Source

fn set_storage(key: &[u8], value: &[u8])

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

Equivalent to Self::set_storage_v1 version with the exception of the return type. Still a valid thing to call for fixed sized storage key, when not interested in the return value.

Source

fn set_storage_v1(key: &[u8], value: &[u8]) -> Option<u32>

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

This version is to be used with a fixed sized storage key. For runtimes supporting transparent hashing, please use the newer version of this function.

Source

fn set_storage_v2(key: &[u8], value: &[u8]) -> Option<u32>

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

The key and value lengths must not exceed the maximums defined by the contracts module parameters.

§Parameters

key: The storage key.
encoded_value: The storage value.

§Return

Returns the size of the pre-existing value at the specified key if any.

Source

fn set_transient_storage(key: &[u8], value: &[u8]) -> Option<u32>

👎Deprecated: Unstable function. Behaviour can change without further notice. Use only for testing.

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

The key and value lengths must not exceed the maximums defined by the contracts module parameters.

§Parameters

key: The storage key.
encoded_value: The storage value.

§Return

Returns the size of the pre-existing value at the specified key if any.

Source

fn sr25519_verify( signature: &[u8; 64], message: &[u8], pub_key: &[u8; 32], ) -> Result<(), ReturnErrorCode>

Verify a sr25519 signature

§Parameters

signature: The signature bytes.
message: The message bytes.

§Errors

Sr25519VerifyFailed

Source

fn take_storage( key: &[u8], output: &mut &mut [u8], ) -> Result<(), ReturnErrorCode>

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

§Parameters

key: The storage key.
output: A reference to the output data buffer to write the storage entry.

§Errors

KeyNotFound

Source

fn take_transient_storage( key: &[u8], output: &mut &mut [u8], ) -> Result<(), ReturnErrorCode>

👎Deprecated: Unstable function. Behaviour can change without further notice. Use only for testing.

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

§Parameters

key: The storage key.
output: A reference to the output data buffer to write the storage entry.

§Errors

KeyNotFound

Source

fn transfer(account_id: &[u8], value: &[u8]) -> Result<(), ReturnErrorCode>

Transfer some amount of funds into the specified account.

§Parameters

account_id: The address of the account to transfer funds to. Should be decodable as an T::AccountId. Traps otherwise.
value: The value to transfer. Should be decodable as a T::Balance. Traps otherwise.

§Errors

TransferFailed

Source

fn terminate(beneficiary: &[u8]) -> !

👎Deprecated: Deprecated, use newer version instead

Remove the calling account and transfer remaining balance.

This is equivalent to calling the newer version of this function

Source

fn terminate_v1(beneficiary: &[u8]) -> !

Remove the calling account and transfer remaining free balance.

This function never returns. Either the termination was successful and the execution of the destroyed contract is halted. Or it failed during the termination which is considered fatal and results in a trap + rollback.

§Parameters

beneficiary: The address of the beneficiary account, Should be decodable as an T::AccountId.

§Traps

The contract is live i.e is already on the call stack.
Failed to send the balance to the beneficiary.
The deletion queue is full.

Source

fn value_transferred(output: &mut &mut [u8])

Stores the value transferred along with this call/instantiate into the supplied buffer. The data is encoded as T::Balance.

If the available space in output is less than the size of the value a trap is triggered.

§Parameters

output: A reference to the output data buffer to write the transferred value.

Source

fn weight_to_fee(gas: u64, output: &mut &mut [u8])

Stores the price for the specified amount of gas into the supplied buffer.

Equivalent to the newer Self::weight_to_fee_v1 version but works with ref_time Weight only. It is recommended to switch to the latest version, once it’s stabilized.

Source

fn weight_to_fee_v1( ref_time_limit: u64, proof_size_limit: u64, output: &mut &mut [u8], )

👎Deprecated: Unstable function. Behaviour can change without further notice. Use only for testing.

Stores the price for the specified amount of gas into the supplied buffer. The data is encoded as T::Balance.

If the available space in output is less than the size of the value a trap is triggered.

§Parameters

ref_time_limit: The ref_time Weight limit to query the price for.
proof_size_limit: The proof_size Weight limit to query the price for.
output: A reference to the output data buffer to write the price.

Source

fn xcm_execute(msg: &[u8]) -> Result<(), ReturnErrorCode>

👎Deprecated: Unstable function. Behaviour can change without further notice. Use only for testing.

Execute an XCM program locally, using the contract’s address as the origin. This is equivalent to dispatching pallet_xcm::execute through call_runtime, except that the function is called directly instead of being dispatched.

§Parameters

msg: The message, should be decodable as a VersionedXcm, traps otherwise.
output: A reference to the output data buffer to write the Outcome

§Return

Returns Error::Success when the XCM execution attempt is successful. When the XCM execution fails, ReturnCode::XcmExecutionFailed is returned

Source

fn xcm_send( dest: &[u8], msg: &[u8], output: &mut [u8; 32], ) -> Result<(), ReturnErrorCode>

👎Deprecated: Unstable function. Behaviour can change without further notice. Use only for testing.

Send an XCM program from the contract to the specified destination. This is equivalent to dispatching pallet_xcm::send through call_runtime, except that the function is called directly instead of being dispatched.

§Parameters

dest: The XCM destination, should be decodable as VersionedLocation, traps otherwise.
msg: The message, should be decodable as a VersionedXcm, traps otherwise.

§Return

Returns ReturnCode::Success when the message was successfully sent. When the XCM execution fails, ReturnErrorCode::XcmSendFailed is returned.

Dyn Compatibility§

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors§

Source §

Trait HostFnCopy item path

Required Methods§

fn account_reentrance_count(account: &[u8]) -> u32

§Parameters

§Return

fn address(output: &mut &mut [u8])

§Parameters

fn lock_delegate_dependency(code_hash: &[u8])

§Parameters

fn balance(output: &mut &mut [u8])

§Parameters

fn block_number(output: &mut &mut [u8])

§Parameters

fn call( callee: &[u8], gas: u64, value: &[u8], input_data: &[u8], output: Option<&mut &mut [u8]>, ) -> Result<(), ReturnErrorCode>

fn call_v1( flags: CallFlags, callee: &[u8], gas: u64, value: &[u8], input_data: &[u8], output: Option<&mut &mut [u8]>, ) -> Result<(), ReturnErrorCode>

fn call_v2( flags: CallFlags, callee: &[u8], ref_time_limit: u64, proof_size_limit: u64, deposit: Option<&[u8]>, value: &[u8], input_data: &[u8], output: Option<&mut &mut [u8]>, ) -> Result<(), ReturnErrorCode>

§Parameters

§Errors

fn call_chain_extension( func_id: u32, input: &[u8], output: Option<&mut &mut [u8]>, ) -> u32

§Note

§Parameters

§Return

fn call_runtime(call: &[u8]) -> Result<(), ReturnErrorCode>

§Parameters

§Return

§Comparison with ChainExtension

fn caller(output: &mut &mut [u8])

§Parameters

fn caller_is_origin() -> bool

§Return

fn caller_is_root() -> u32

fn clear_storage(key: &[u8])

fn clear_storage_v1(key: &[u8]) -> Option<u32>

§Parameters

§Return

fn clear_transient_storage(key: &[u8]) -> Option<u32>

§Parameters

§Return

fn code_hash( account_id: &[u8], output: &mut [u8], ) -> Result<(), ReturnErrorCode>

§Parameters

§Errors

fn contains_storage(key: &[u8]) -> Option<u32>

fn contains_storage_v1(key: &[u8]) -> Option<u32>

§Parameters

§Return

fn contains_transient_storage(key: &[u8]) -> Option<u32>

§Parameters

§Return

fn debug_message(str: &[u8]) -> Result<(), ReturnErrorCode>

§Note

fn delegate_call( flags: CallFlags, code_hash: &[u8], input_data: &[u8], output: Option<&mut &mut [u8]>, ) -> Result<(), ReturnErrorCode>

§Parameters

§Errors

fn deposit_event(topics: &[u8], data: &[u8])

§Parameters

fn ecdsa_recover( signature: &[u8; 65], message_hash: &[u8; 32], output: &mut [u8; 33], ) -> Result<(), ReturnErrorCode>

§Parameters

§Errors

fn ecdsa_to_eth_address( pubkey: &[u8; 33], output: &mut [u8; 20], ) -> Result<(), ReturnErrorCode>

§Parameters

§Errors

fn gas_left(out: &mut &mut [u8])

fn gas_left_v1(output: &mut &mut [u8])

§Parameters

fn get_storage( key: &[u8], output: &mut &mut [u8], ) -> Result<(), ReturnErrorCode>

fn get_storage_v1( key: &[u8], output: &mut &mut [u8], ) -> Result<(), ReturnErrorCode>

§Parameters

§Errors

fn get_transient_storage( key: &[u8], output: &mut &mut [u8], ) -> Result<(), ReturnErrorCode>

§Parameters

§Errors

fn hash_sha2_256(input: &[u8], output: &mut [u8; 32])

§Notes

§Parameters

fn hash_keccak_256(input: &[u8], output: &mut [u8; 32])

§Notes

§Parameters

fn hash_blake2_256(input: &[u8], output: &mut [u8; 32])

§Notes

§Parameters

Trait HostFn

§Comparison with `ChainExtension`