Trait External 

pub trait External {
    // Required methods
    fn storage_set(
        &mut self,
        key: &[u8],
        value: &[u8],
    ) -> Result<(), VMLogicError>;
    fn storage_get<'a>(
        &'a self,
        key: &[u8],
    ) -> Result<Option<Box<dyn ValuePtr + 'a>>, VMLogicError>;
    fn storage_remove(&mut self, key: &[u8]) -> Result<(), VMLogicError>;
    fn storage_remove_subtree(
        &mut self,
        prefix: &[u8],
    ) -> Result<(), VMLogicError>;
    fn storage_has_key(&mut self, key: &[u8]) -> Result<bool, VMLogicError>;
    fn create_receipt(
        &mut self,
        receipt_indices: Vec<ReceiptIndex>,
        receiver_id: AccountId,
    ) -> Result<ReceiptIndex, VMLogicError>;
    fn append_action_create_account(
        &mut self,
        receipt_index: ReceiptIndex,
    ) -> Result<(), VMLogicError>;
    fn append_action_deploy_contract(
        &mut self,
        receipt_index: ReceiptIndex,
        code: Vec<u8>,
    ) -> Result<(), VMLogicError>;
    fn append_action_function_call(
        &mut self,
        receipt_index: ReceiptIndex,
        method_name: Vec<u8>,
        arguments: Vec<u8>,
        attached_deposit: Balance,
        prepaid_gas: Gas,
    ) -> Result<(), VMLogicError>;
    fn append_action_transfer(
        &mut self,
        receipt_index: ReceiptIndex,
        amount: Balance,
    ) -> Result<(), VMLogicError>;
    fn append_action_stake(
        &mut self,
        receipt_index: ReceiptIndex,
        stake: Balance,
        public_key: PublicKey,
    ) -> Result<(), VMLogicError>;
    fn append_action_add_key_with_full_access(
        &mut self,
        receipt_index: ReceiptIndex,
        public_key: PublicKey,
        nonce: u64,
    ) -> Result<(), VMLogicError>;
    fn append_action_add_key_with_function_call(
        &mut self,
        receipt_index: ReceiptIndex,
        public_key: PublicKey,
        nonce: u64,
        allowance: Option<Balance>,
        receiver_id: AccountId,
        method_names: Vec<Vec<u8>>,
    ) -> Result<(), VMLogicError>;
    fn append_action_delete_key(
        &mut self,
        receipt_index: ReceiptIndex,
        public_key: PublicKey,
    ) -> Result<(), VMLogicError>;
    fn append_action_delete_account(
        &mut self,
        receipt_index: ReceiptIndex,
        beneficiary_id: AccountId,
    ) -> Result<(), VMLogicError>;
    fn get_touched_nodes_count(&self) -> u64;
    fn reset_touched_nodes_counter(&mut self);
    fn validator_stake(
        &self,
        account_id: &AccountId,
    ) -> Result<Option<Balance>, VMLogicError>;
    fn validator_total_stake(&self) -> Result<Balance, VMLogicError>;
}

An external blockchain interface for the Runtime logic

Required Methods

fn storage_set(&mut self, key: &[u8], value: &[u8]) -> Result<(), VMLogicError>

Write to the storage trie of the current account

Arguments

• key - a key for a new value
• value - a new value to be set

Errors

This function could return HostErrorOrStorageError::StorageError on underlying DB failure

Example

assert_eq!(external.storage_set(b"key42", b"value1337"), Ok(()));
// Should return an old value if the key exists
assert_eq!(external.storage_set(b"key42", b"new_value"), Ok(()));

fn storage_get<'a>( &'a self, key: &[u8], ) -> Result<Option<Box<dyn ValuePtr + 'a>>, VMLogicError>

Reads from the storage trie of the current account

Arguments

• key - a key to read

Errors

This function could return HostErrorOrStorageError::StorageError on underlying DB failure

Example

external.storage_set(b"key42", b"value1337").unwrap();
assert_eq!(external.storage_get(b"key42").unwrap().map(|ptr| ptr.deref().unwrap()), Some(b"value1337".to_vec()));
// Returns Ok(None) if there is no value for a key
assert_eq!(external.storage_get(b"no_key").unwrap().map(|ptr| ptr.deref().unwrap()), None);

fn storage_remove(&mut self, key: &[u8]) -> Result<(), VMLogicError>

Removes the key from the storage

Arguments

• key - a key to remove

Errors

This function could return HostErrorOrStorageError::StorageError on underlying DB failure

Example

external.storage_set(b"key42", b"value1337").unwrap();
// Returns Ok if exists
assert_eq!(external.storage_remove(b"key42"), Ok(()));
// Returns Ok if there was no value
assert_eq!(external.storage_remove(b"no_value_key"), Ok(()));

fn storage_remove_subtree(&mut self, prefix: &[u8]) -> Result<(), VMLogicError>

Removes all keys under given suffix in the storage.

Arguments

• prefix - a prefix for all keys to remove

Errors

This function could return HostErrorOrStorageError::StorageError on underlying DB failure

Example

external.storage_set(b"key1", b"value1337").unwrap();
external.storage_set(b"key2", b"value1337").unwrap();
assert_eq!(external.storage_remove_subtree(b"key"), Ok(()));
assert!(!external.storage_has_key(b"key1").unwrap());
assert!(!external.storage_has_key(b"key2").unwrap());

fn storage_has_key(&mut self, key: &[u8]) -> Result<bool, VMLogicError>

Check whether key exists. Returns Ok(true) if key exists or Ok(false) otherwise

Arguments

• key - a key to check

Errors

This function could return HostErrorOrStorageError::StorageError on underlying DB failure

Example

external.storage_set(b"key42", b"value1337").unwrap();
// Returns value if exists
assert_eq!(external.storage_has_key(b"key42"), Ok(true));
// Returns None if there was no value
assert_eq!(external.storage_has_key(b"no_value_key"), Ok(false));

fn create_receipt( &mut self, receipt_indices: Vec<ReceiptIndex>, receiver_id: AccountId, ) -> Result<ReceiptIndex, VMLogicError>

Creates a receipt which will be executed after receipt_indices

Arguments

• receipt_indices - a list of receipt indices the new receipt is depend on

Example

let receipt_index_one = external.create_receipt(vec![], "charli.near".to_owned()).unwrap();
let receipt_index_two = external.create_receipt(vec![receipt_index_one], "bob.near".to_owned());

Panics

Panics if one of receipt_indices is missing

fn append_action_create_account( &mut self, receipt_index: ReceiptIndex, ) -> Result<(), VMLogicError>

Attaches an Action::CreateAccount action to an existing receipt

Arguments

• receipt_index - an index of Receipt to append an action

Example

let receipt_index = external.create_receipt(vec![], "charli.near".to_owned()).unwrap();
external.append_action_create_account(receipt_index).unwrap();

Panics

Panics if receipt_index is missing

fn append_action_deploy_contract( &mut self, receipt_index: ReceiptIndex, code: Vec<u8>, ) -> Result<(), VMLogicError>

Attaches an Action::DeployContract action to an existing receipt

Arguments

• receipt_index - an index of Receipt to append an action
• code - a Wasm code to attach

Example

let receipt_index = external.create_receipt(vec![], "charli.near".to_owned()).unwrap();
external.append_action_deploy_contract(receipt_index, b"some valid Wasm code".to_vec()).unwrap();

Panics

Panics if receipt_index is missing

fn append_action_function_call( &mut self, receipt_index: ReceiptIndex, method_name: Vec<u8>, arguments: Vec<u8>, attached_deposit: Balance, prepaid_gas: Gas, ) -> Result<(), VMLogicError>

Attaches an Action::FunctionCall action to an existing receipt

Arguments

• receipt_index - an index of Receipt to append an action
• method_name - a name of the contract method to call
• arguments - a Wasm code to attach
• attached_deposit - amount of tokens to transfer with the call
• prepaid_gas - amount of prepaid gas to attach to the call

Example

let receipt_index = external.create_receipt(vec![], "charli.near".to_owned()).unwrap();
external.append_action_function_call(
    receipt_index,
    b"method_name".to_vec(),
    b"{serialised: arguments}".to_vec(),
    100000u128,
    100u64
).unwrap();

Panics

Panics if receipt_index is missing

fn append_action_transfer( &mut self, receipt_index: ReceiptIndex, amount: Balance, ) -> Result<(), VMLogicError>

Attaches an TransferAction action to an existing receipt

Arguments

• receipt_index - an index of Receipt to append an action
• amount - amount of tokens to transfer

Example

let receipt_index = external.create_receipt(vec![], "charli.near".to_owned()).unwrap();
external.append_action_transfer(
    receipt_index,
    100000u128,
).unwrap();

Panics

Panics if receipt_index is missing

fn append_action_stake( &mut self, receipt_index: ReceiptIndex, stake: Balance, public_key: PublicKey, ) -> Result<(), VMLogicError>

Attaches an StakeAction action to an existing receipt

Arguments

• receipt_index - an index of Receipt to append an action
• stake - amount of tokens to stake
• public_key - a validator public key

Example

let receipt_index = external.create_receipt(vec![], "charli.near".to_owned()).unwrap();
external.append_action_stake(
    receipt_index,
    100000u128,
    b"some public key".to_vec()
).unwrap();

Panics

Panics if receipt_index is missing

fn append_action_add_key_with_full_access( &mut self, receipt_index: ReceiptIndex, public_key: PublicKey, nonce: u64, ) -> Result<(), VMLogicError>

Attaches an AddKeyAction action to an existing receipt

Arguments

• receipt_index - an index of Receipt to append an action
• public_key - a public key for an access key
• nonce - a nonce

Example

let receipt_index = external.create_receipt(vec![], "charli.near".to_owned()).unwrap();
external.append_action_add_key_with_full_access(
    receipt_index,
    b"some public key".to_vec(),
    0u64
).unwrap();

Panics

Panics if receipt_index is missing

fn append_action_add_key_with_function_call( &mut self, receipt_index: ReceiptIndex, public_key: PublicKey, nonce: u64, allowance: Option<Balance>, receiver_id: AccountId, method_names: Vec<Vec<u8>>, ) -> Result<(), VMLogicError>

Attaches an AddKeyAction action to an existing receipt with AccessKeyPermission::FunctionCall

Arguments

• receipt_index - an index of Receipt to append an action
• public_key - a public key for an access key
• nonce - a nonce
• allowance - amount of tokens allowed to spend by this access key
• receiver_id - a contract witch will be allowed to call with this access key
• method_names - a list of method names is allowed to call with this access key (empty = any method)

Example

let receipt_index = external.create_receipt(vec![], "charli.near".to_owned()).unwrap();
external.append_action_add_key_with_function_call(
    receipt_index,
    b"some public key".to_vec(),
    0u64,
    None,
    "bob.near".to_owned(),
    vec![b"foo".to_vec(), b"bar".to_vec()]
).unwrap();

Panics

Panics if receipt_index is missing

fn append_action_delete_key( &mut self, receipt_index: ReceiptIndex, public_key: PublicKey, ) -> Result<(), VMLogicError>

Attaches an DeleteKeyAction action to an existing receipt

Arguments

• receipt_index - an index of Receipt to append an action
• public_key - a public key for an access key to delete

Example

let receipt_index = external.create_receipt(vec![], "charli.near".to_owned()).unwrap();
external.append_action_delete_key(
    receipt_index,
    b"some public key".to_vec()
).unwrap();

Panics

Panics if receipt_index is missing

fn append_action_delete_account( &mut self, receipt_index: ReceiptIndex, beneficiary_id: AccountId, ) -> Result<(), VMLogicError>

Attaches an DeleteAccountAction action to an existing receipt

Arguments

• receipt_index - an index of Receipt to append an action
• beneficiary_id - an account id to which the rest of the funds of the removed account will be transferred

Example

let receipt_index = external.create_receipt(vec![], "charli.near".to_owned()).unwrap();
external.append_action_delete_account(
    receipt_index,
    "sam".to_owned()
).unwrap();

Panics

Panics if receipt_index is missing

fn get_touched_nodes_count(&self) -> u64

Returns amount of touched trie nodes by storage operations

fn reset_touched_nodes_counter(&mut self)

Resets amount of touched trie nodes by storage operations

fn validator_stake( &self, account_id: &AccountId, ) -> Result<Option<Balance>, VMLogicError>

Returns the validator stake for given account in the current epoch. If the account is not a validator, returns None.

fn validator_total_stake(&self) -> Result<Balance, VMLogicError>

Returns total stake of validators in the current epoch.

Implementors

impl External for MockedExternal