Trait near_vm_logic::External

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pub trait External {
    // Required methods
    fn storage_set(
        &mut self,
        key: &[u8],
        value: &[u8]
    ) -> Result<(), VMLogicError>;
    fn storage_get<'a>(
        &'a self,
        key: &[u8],
        mode: StorageGetMode
    ) -> 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 generate_data_id(&mut self) -> CryptoHash;
    fn get_trie_nodes_count(&self) -> TrieNodesCount;
    fn validator_stake(
        &self,
        account_id: &AccountId
    ) -> Result<Option<Balance>, VMLogicError>;
    fn validator_total_stake(&self) -> Result<Balance, VMLogicError>;
}
Expand description

An external blockchain interface for the Runtime logic

Required Methods§

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

Write value to the key of the storage trie associated with the current account.

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

Read key from the storage trie associated with the current account.

Arguments

  • key - the key to read

  • mode- whether the lookup will be performed through flat storage or trie

Errors

This function could return near_vm_errors::VMRunnerError::ExternalError.

Example

external.storage_set(b"key42", b"value1337").unwrap();
assert_eq!(external.storage_get(b"key42", StorageGetMode::Trie).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", StorageGetMode::Trie).unwrap().map(|ptr| ptr.deref().unwrap()), None);
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fn storage_remove(&mut self, key: &[u8]) -> Result<(), VMLogicError>

Removes the key from the storage trie associated with the current account.

The operation will succeed even if the key does not exist.

Arguments
  • key - the key to remove
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(()));
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fn storage_remove_subtree(&mut self, prefix: &[u8]) -> Result<(), VMLogicError>

Note: The method is currently unused and untested.

Removes all keys with a given prefix from the storage trie associated with current account.

Arguments
  • prefix - a prefix for all keys to remove
Errors

This function could return [near_vm_errors::VMError].

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

Check whether the key is present in the storage trie associated with the current account.

Returns Ok(true) if key is present, Ok(false) if the key is not present.

Arguments
  • key - a key to check
Errors

This function could return [near_vm_errors::VMError].

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));
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fn generate_data_id(&mut self) -> CryptoHash

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fn get_trie_nodes_count(&self) -> TrieNodesCount

Returns amount of touched trie nodes by storage operations

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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.

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

Returns total stake of validators in the current epoch.

Implementors§