ethers-rs/ethers-contract/ethers-contract-derive/src/error.rs

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//! Helper functions for deriving `EthError`
use crate::{calllike::*, utils, utils::ident};
use ethers_core::{
abi::{ErrorExt, HumanReadableParser},
macros::{ethers_contract_crate, ethers_core_crate},
};
use proc_macro2::TokenStream;
use quote::quote;
use syn::{parse::Error, DeriveInput};
/// Generates the `EthError` trait support
pub(crate) fn derive_eth_error_impl(input: DeriveInput) -> TokenStream {
let attributes = match parse_calllike_attributes(&input, "etherror") {
Ok(attributes) => attributes,
Err(errors) => return errors,
};
let error_name = attributes.name.map(|(s, _)| s).unwrap_or_else(|| input.ident.to_string());
let mut error = if let Some((src, span)) = attributes.abi {
let raw_function_sig = src.trim_start_matches("error ").trim_start();
// try to parse as solidity error
if let Ok(fun) = HumanReadableParser::parse_error(&src) {
fun
} else {
// try to determine the abi by using its fields at runtime
return match derive_trait_impls_with_abi_type(
&input,
&error_name,
Some(raw_function_sig),
) {
Ok(derived) => derived,
Err(err) => {
Error::new(span, format!("Unable to determine ABI for `{src}` : {err}"))
.to_compile_error()
}
}
}
} else {
// try to determine the abi by using its fields at runtime
return match derive_trait_impls_with_abi_type(&input, &error_name, None) {
Ok(derived) => derived,
Err(err) => err.to_compile_error(),
}
};
error.name = error_name.clone();
let abi = error.abi_signature();
let selector = utils::selector(error.selector());
let decode_impl = derive_decode_impl_from_params(&error.inputs, ident("EthError"));
derive_trait_impls(&input, &error_name, quote! {#abi.into()}, Some(selector), decode_impl)
}
/// Use the `AbiType` trait to determine the correct `ParamType` and signature at runtime
fn derive_trait_impls_with_abi_type(
input: &DeriveInput,
function_call_name: &str,
abi_signature: Option<&str>,
) -> Result<TokenStream, Error> {
let abi_signature = if let Some(abi) = abi_signature {
quote! {#abi}
} else {
utils::derive_abi_signature_with_abi_type(input, function_call_name, "EthError")?
};
let abi_signature = quote! {
#abi_signature.into()
};
let decode_impl = derive_decode_impl_with_abi_type(input, ident("EthError"))?;
Ok(derive_trait_impls(input, function_call_name, abi_signature, None, decode_impl))
}
/// Generates the EthError implementation
pub fn derive_trait_impls(
input: &DeriveInput,
function_call_name: &str,
abi_signature: TokenStream,
selector: Option<TokenStream>,
decode_impl: TokenStream,
) -> TokenStream {
// the ethers crates to use
let core_crate = ethers_core_crate();
let contract_crate = ethers_contract_crate();
let struct_name = &input.ident;
let selector = selector.unwrap_or_else(|| {
quote! {
#core_crate::utils::id(Self::abi_signature())
}
});
let etherror_impl = quote! {
impl #contract_crate::EthError for #struct_name {
fn error_name() -> ::std::borrow::Cow<'static, str> {
#function_call_name.into()
}
fn selector() -> #core_crate::types::Selector {
#selector
}
fn abi_signature() -> ::std::borrow::Cow<'static, str> {
#abi_signature
}
}
};
let codec_impl = derive_codec_impls(input, decode_impl, ident("EthError"));
quote! {
#etherror_impl
#codec_impl
}
}