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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,135 @@ | ||
| use crate::{Context, ExitError, ExitFatal, ExitReason, ExitRevert, ExitSucceed, Transfer}; | ||
| use alloc::collections::BTreeMap; | ||
| use primitive_types::{H160, H256}; | ||
|
|
||
| /// A precompile result. | ||
| pub type PrecompileResult = Result<PrecompileOutput, PrecompileFailure>; | ||
|
|
||
| /// Data returned by a precompile on success. | ||
| #[derive(Debug, Eq, PartialEq, Clone)] | ||
| pub struct PrecompileOutput { | ||
| pub exit_status: ExitSucceed, | ||
| pub output: Vec<u8>, | ||
| } | ||
|
|
||
| /// Data returned by a precompile in case of failure. | ||
| #[derive(Debug, Eq, PartialEq, Clone)] | ||
| pub enum PrecompileFailure { | ||
| /// Reverts the state changes and consume all the gas. | ||
| Error { exit_status: ExitError }, | ||
| /// Reverts the state changes. | ||
| /// Returns the provided error message. | ||
| Revert { | ||
| exit_status: ExitRevert, | ||
| output: Vec<u8>, | ||
| }, | ||
| /// Mark this failure as fatal, and all EVM execution stacks must be exited. | ||
| Fatal { exit_status: ExitFatal }, | ||
| } | ||
|
|
||
| impl From<ExitError> for PrecompileFailure { | ||
| fn from(error: ExitError) -> PrecompileFailure { | ||
| PrecompileFailure::Error { exit_status: error } | ||
| } | ||
| } | ||
|
|
||
| /// Handle provided to a precompile to interact with the EVM. | ||
| pub trait PrecompileHandle { | ||
| /// Perform subcall in provided context. | ||
| /// Precompile specifies in which context the subcall is executed. | ||
| fn call( | ||
| &mut self, | ||
| to: H160, | ||
| transfer: Option<Transfer>, | ||
| input: Vec<u8>, | ||
| gas_limit: Option<u64>, | ||
| is_static: bool, | ||
| context: &Context, | ||
| ) -> (ExitReason, Vec<u8>); | ||
|
|
||
| /// Record cost to the Runtime gasometer. | ||
| fn record_cost(&mut self, cost: u64) -> Result<(), ExitError>; | ||
|
|
||
| /// Retreive the remaining gas. | ||
| fn remaining_gas(&self) -> u64; | ||
|
|
||
| /// Record a log. | ||
| fn log(&mut self, address: H160, topics: Vec<H256>, data: Vec<u8>) -> Result<(), ExitError>; | ||
|
|
||
| /// Retreive the code address (what is the address of the precompile being called). | ||
| fn code_address(&self) -> H160; | ||
|
|
||
| /// Retreive the input data the precompile is called with. | ||
| fn input(&self) -> &[u8]; | ||
|
|
||
| /// Retreive the context in which the precompile is executed. | ||
| fn context(&self) -> &Context; | ||
|
|
||
| /// Is the precompile call is done statically. | ||
| fn is_static(&self) -> bool; | ||
|
|
||
| /// Retreive the gas limit of this call. | ||
| fn gas_limit(&self) -> Option<u64>; | ||
| } | ||
|
|
||
| /// A set of precompiles. | ||
| /// Checks of the provided address being in the precompile set should be | ||
| /// as cheap as possible since it may be called often. | ||
| pub trait PrecompileSet { | ||
| /// Tries to execute a precompile in the precompile set. | ||
| /// If the provided address is not a precompile, returns None. | ||
| fn execute(&self, handle: &mut impl PrecompileHandle) -> Option<PrecompileResult>; | ||
|
|
||
| /// Check if the given address is a precompile. Should only be called to | ||
| /// perform the check while not executing the precompile afterward, since | ||
| /// `execute` already performs a check internally. | ||
| fn is_precompile(&self, address: H160) -> bool; | ||
| } | ||
|
|
||
| impl PrecompileSet for () { | ||
| fn execute(&self, _: &mut impl PrecompileHandle) -> Option<PrecompileResult> { | ||
| None | ||
| } | ||
|
|
||
| fn is_precompile(&self, _: H160) -> bool { | ||
| false | ||
| } | ||
| } | ||
|
|
||
| /// Precompiles function signature. Expected input arguments are: | ||
| /// * Input | ||
| /// * Gas limit | ||
| /// * Context | ||
| /// * Is static | ||
| /// | ||
| /// In case of success returns the output and the cost. | ||
| pub type PrecompileFn = | ||
| fn(&[u8], Option<u64>, &Context, bool) -> Result<(PrecompileOutput, u64), PrecompileFailure>; | ||
|
|
||
| impl PrecompileSet for BTreeMap<H160, PrecompileFn> { | ||
| fn execute(&self, handle: &mut impl PrecompileHandle) -> Option<PrecompileResult> { | ||
| let address = handle.code_address(); | ||
|
|
||
| self.get(&address).map(|precompile| { | ||
| let input = handle.input(); | ||
| let gas_limit = handle.gas_limit(); | ||
| let context = handle.context(); | ||
| let is_static = handle.is_static(); | ||
|
|
||
| match (*precompile)(input, gas_limit, context, is_static) { | ||
| Ok((output, cost)) => { | ||
| handle.record_cost(cost)?; | ||
| Ok(output) | ||
| } | ||
| Err(err) => Err(err), | ||
| } | ||
| }) | ||
| } | ||
|
|
||
| /// Check if the given address is a precompile. Should only be called to | ||
| /// perform the check while not executing the precompile afterward, since | ||
| /// `execute` already performs a check internally. | ||
| fn is_precompile(&self, address: H160) -> bool { | ||
| self.contains_key(&address) | ||
| } | ||
| } |