Struct ContractsQueryApi 

pub struct ContractsQueryApi<'api> { /* private fields */ }

Implementations

impl<'api> ContractsQueryApi<'api>

pub async fn pristine_code(&self, key_0: H256) -> Result<Option<Vec<u8>>>

A mapping from a contract’s code hash to its code.

pub async fn code_info_of(&self, key_0: H256) -> Result<Option<CodeInfo>>

A mapping from a contract’s code hash to its code info.

pub async fn nonce(&self) -> Result<u64>

This is a monotonic counter incremented on contract instantiation.

This is used in order to generate unique trie ids for contracts. The trie id of a new contract is calculated from hash(account_id, nonce). The nonce is required because otherwise the following sequence would lead to a possible collision of storage:

1. Create a new contract.
2. Terminate the contract.
3. Immediately recreate the contract with the same account_id.

This is bad because the contents of a trie are deleted lazily and there might be storage of the old instantiation still in it when the new contract is created. Please note that we can’t replace the counter by the block number because the sequence above can happen in the same block. We also can’t keep the account counter in memory only because storage is the only way to communicate across different extrinsics in the same block.

Note

Do not use it to determine the number of contracts. It won’t be decremented if a contract is destroyed.

pub async fn contract_info_of( &self, key_0: AccountId, ) -> Result<Option<ContractInfo>>

The code associated with a given account.

TWOX-NOTE: SAFE since AccountId is a secure hash.

pub async fn deletion_queue(&self, key_0: u32) -> Result<Option<Vec<u8>>>

Evicted contracts that await child trie deletion.

Child trie deletion is a heavy operation depending on the amount of storage items stored in said trie. Therefore this operation is performed lazily in on_idle.

pub async fn deletion_queue_counter(&self) -> Result<DeletionQueueManager>

A pair of monotonic counters used to track the latest contract marked for deletion and the latest deleted contract in queue.

pub async fn migration_in_progress(&self) -> Result<Option<Vec<u8>>>

A migration can span across multiple blocks. This storage defines a cursor to track the progress of the migration, enabling us to resume from the last completed position.

Trait Implementations

impl<'api> Clone for ContractsQueryApi<'api>

fn clone(&self) -> ContractsQueryApi<'api>

Returns a duplicate of the value.

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

Performs copy-assignment from source.