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use crate::{
host::context::{BlockchainUpdate, TxCache, TxInput, TxResult, TxTokenTransfer},
host::runtime::{RuntimeInstanceCallLambda, RuntimeRef},
types::Address,
};
pub trait BuiltinFunction {
/// Function name corresponding the builtin function implementation.
///
/// Currently not used.
fn name(&self) -> &str;
/// Extracts data relating ESDT transfers handled by the builtin function, if applicable.
fn extract_esdt_transfers(&self, tx_input: &TxInput) -> BuiltinFunctionEsdtTransferInfo {
BuiltinFunctionEsdtTransferInfo::empty(tx_input)
}
/// Executes builtin function for the givn `TxInput` and with access to the underlying contracts states via the `TxCache`.
///
/// A few builtin functions (the ones transferring ESDT) can also call the VM after they finish,
/// so they are given the extra reference to the VM and a lambda closure to execute on the VM
fn execute<F>(
&self,
tx_input: TxInput,
tx_cache: TxCache,
runtime: &RuntimeRef,
lambda: F,
) -> (TxResult, BlockchainUpdate)
where
F: RuntimeInstanceCallLambda;
}
/// Contains a builtin function call ESDT transfers (if any) and the real recipient of the transfer
/// (can be different from the "to" field.)
pub struct BuiltinFunctionEsdtTransferInfo {
pub real_recipient: Address,
pub transfers: Vec<TxTokenTransfer>,
}
impl BuiltinFunctionEsdtTransferInfo {
pub fn empty(tx_input: &TxInput) -> Self {
BuiltinFunctionEsdtTransferInfo {
real_recipient: tx_input.to.clone(),
transfers: Vec::new(),
}
}
pub fn is_empty(&self) -> bool {
self.transfers.is_empty()
}
}