496 lines
20 KiB
Rust
496 lines
20 KiB
Rust
//! Helper functions for deriving `EthEvent`
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use crate::{abi_ty, utils};
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use ethers_contract_abigen::Source;
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use ethers_core::{
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abi::{Event, EventExt, EventParam, HumanReadableParser},
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macros::{ethers_contract_crate, ethers_core_crate},
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};
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use hex::FromHex;
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use proc_macro2::{Span, TokenStream};
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use quote::quote;
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use syn::{
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parse::Error, spanned::Spanned, AttrStyle, Data, DeriveInput, Field, Fields, Lit, Meta,
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NestedMeta,
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};
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/// Generates the `EthEvent` trait support
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pub(crate) fn derive_eth_event_impl(input: DeriveInput) -> Result<TokenStream, Error> {
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let name = &input.ident;
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let attributes = parse_event_attributes(&input)?;
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let mut event = if let Some((src, span)) = attributes.abi {
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// try to parse as a Solidity event
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match HumanReadableParser::parse_event(&src) {
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Ok(event) => Ok(event),
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Err(parse_err) => {
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match src.parse::<Source>().and_then(|s| s.get()) {
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Ok(abi) => {
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// try to derive the signature from the abi from the parsed abi
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// TODO(mattsse): this will fail for events that contain other non
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// elementary types in their abi because the parser
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// doesn't know how to substitute the types.
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// This could be mitigated by getting the ABI of each non elementary type
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// at runtime and computing the the signature as a Lazy static.
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match HumanReadableParser::parse_event(&abi) {
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Ok(event) => Ok(event),
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// Ignore parse_err since this is a valid [Source]
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Err(err) => Err(Error::new(span, err)),
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}
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}
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Err(source_err) => {
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// Return both error messages
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let mut error = Error::new(span, parse_err);
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error.combine(Error::new(span, source_err));
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Err(error)
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}
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}
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}
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}
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} else {
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// try to determine the abi from the fields
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derive_abi_event_from_fields(&input)
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}?;
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if let Some((attribute_name, _)) = attributes.name {
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event.name = attribute_name;
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}
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if let Some((anon, _)) = attributes.anonymous.as_ref() {
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event.anonymous = *anon;
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}
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let decode_log_impl = derive_decode_from_log_impl(&input, &event)?;
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let (abi, event_sig) = (event.abi_signature(), event.signature());
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let signature = if let Some((hash, _)) = attributes.signature_hash {
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utils::signature(&hash)
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} else {
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utils::signature(event_sig.as_bytes())
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};
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let anon = attributes.anonymous.map(|(b, _)| b).unwrap_or_default();
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let event_name = &event.name;
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let ethers_core = ethers_core_crate();
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let ethers_contract = ethers_contract_crate();
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let ethevent_impl = quote! {
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impl #ethers_contract::EthEvent for #name {
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fn name() -> ::std::borrow::Cow<'static, str> {
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#event_name.into()
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}
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fn signature() -> #ethers_core::types::H256 {
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#signature
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}
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fn abi_signature() -> ::std::borrow::Cow<'static, str> {
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#abi.into()
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}
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fn decode_log(log: &#ethers_core::abi::RawLog) -> ::std::result::Result<Self, #ethers_core::abi::Error> where Self: Sized {
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#decode_log_impl
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}
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fn is_anonymous() -> bool {
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#anon
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}
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}
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};
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let tokenize_impl = abi_ty::derive_tokenizeable_impl(&input)?;
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Ok(quote! {
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#tokenize_impl
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#ethevent_impl
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})
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}
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/// Internal helper type for an event/log
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struct EventField {
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topic_name: Option<String>,
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index: usize,
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param: EventParam,
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}
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impl EventField {
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fn is_indexed(&self) -> bool {
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self.topic_name.is_some()
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}
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}
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fn derive_decode_from_log_impl(input: &DeriveInput, event: &Event) -> Result<TokenStream, Error> {
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let ethers_core = ethers_core_crate();
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let fields: Vec<_> = match input.data {
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Data::Struct(ref data) => match data.fields {
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Fields::Named(ref fields) => {
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if fields.named.len() != event.inputs.len() {
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return Err(Error::new(
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fields.span(),
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format!(
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"EthEvent {}'s fields length don't match with signature inputs {}",
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event.name,
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event.abi_signature()
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),
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))
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}
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fields.named.iter().collect()
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}
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Fields::Unnamed(ref fields) => {
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if fields.unnamed.len() != event.inputs.len() {
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return Err(Error::new(
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fields.span(),
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format!(
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"EthEvent {}'s fields length don't match with signature inputs {}",
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event.name,
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event.abi_signature()
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),
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))
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}
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fields.unnamed.iter().collect()
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}
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Fields::Unit => {
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// Empty structs or unit, no fields
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vec![]
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}
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},
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Data::Enum(_) => {
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return Err(Error::new(input.span(), "EthEvent cannot be derived for enums"))
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}
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Data::Union(_) => {
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return Err(Error::new(input.span(), "EthEvent cannot be derived for unions"))
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}
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};
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// decode
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let (signature_check, flat_topics_init, topic_tokens_len_check) = if event.anonymous {
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(
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None,
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quote! {
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let flat_topics = topics.iter().flat_map(|t| t.as_ref().to_vec()).collect::<Vec<u8>>();
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},
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quote! {
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if topic_tokens.len() != topics.len() {
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return Err(#ethers_core::abi::Error::InvalidData);
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}
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},
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)
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} else {
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(
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Some(quote! {
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let event_signature = topics.get(0).ok_or(#ethers_core::abi::Error::InvalidData)?;
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if event_signature != &Self::signature() {
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return Err(#ethers_core::abi::Error::InvalidData);
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}
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}),
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quote! {
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let flat_topics = topics.iter().skip(1).flat_map(|t| t.as_ref().to_vec()).collect::<Vec<u8>>();
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},
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quote! {
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if topic_tokens.len() != topics.len() - 1 {
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return Err(#ethers_core::abi::Error::InvalidData);
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}
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},
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)
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};
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// Event with no fields, can skip decoding
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if fields.is_empty() {
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return Ok(quote! {
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let #ethers_core::abi::RawLog {topics, data} = log;
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#signature_check
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if topics.len() != 1usize || !data.is_empty() {
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return Err(::ethers_core::abi::Error::InvalidData);
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}
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#ethers_core::abi::Tokenizable::from_token(#ethers_core::abi::Token::Tuple(::std::vec::Vec::new())).map_err(|_|#ethers_core::abi::Error::InvalidData)
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})
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}
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let mut event_fields = Vec::with_capacity(fields.len());
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for (index, field) in fields.iter().enumerate() {
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let mut param = event.inputs[index].clone();
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let (topic_name, indexed) = parse_field_attributes(field)?;
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if indexed {
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param.indexed = true;
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}
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let topic_name =
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param.indexed.then(|| topic_name.or_else(|| Some(param.name.clone()))).flatten();
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event_fields.push(EventField { topic_name, index, param });
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}
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// convert fields to params list
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let topic_types = event_fields
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.iter()
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.filter(|f| f.is_indexed())
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.map(|f| utils::topic_param_type_quote(&f.param.kind));
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let topic_types_init = quote! {let topic_types = ::std::vec![#( #topic_types ),*];};
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let data_types = event_fields
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.iter()
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.filter(|f| !f.is_indexed())
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.map(|f| utils::param_type_quote(&f.param.kind));
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let data_types_init = quote! {let data_types = [#( #data_types ),*];};
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// check if indexed are sorted
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let tokens_init = if event_fields
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.iter()
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.filter(|f| f.is_indexed())
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.enumerate()
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.all(|(idx, f)| f.index == idx)
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{
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quote! {
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let topic_tokens = #ethers_core::abi::decode(&topic_types, &flat_topics)?;
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#topic_tokens_len_check
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let data_tokens = #ethers_core::abi::decode(&data_types, data)?;
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let tokens:Vec<_> = topic_tokens.into_iter().chain(data_tokens.into_iter()).collect();
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}
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} else {
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let swap_tokens = event_fields.iter().map(|field| {
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if field.is_indexed() {
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quote! { topic_tokens.remove(0) }
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} else {
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quote! { data_tokens.remove(0) }
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}
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});
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quote! {
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let mut topic_tokens = #ethers_core::abi::decode(&topic_types, &flat_topics)?;
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#topic_tokens_len_check
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let mut data_tokens = #ethers_core::abi::decode(&data_types, &data)?;
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let mut tokens = Vec::with_capacity(topics.len() + data_tokens.len());
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#( tokens.push(#swap_tokens); )*
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}
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};
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Ok(quote! {
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let #ethers_core::abi::RawLog {data, topics} = log;
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#signature_check
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#topic_types_init
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#data_types_init
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#flat_topics_init
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#tokens_init
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#ethers_core::abi::Tokenizable::from_token(#ethers_core::abi::Token::Tuple(tokens)).map_err(|_|#ethers_core::abi::Error::InvalidData)
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})
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}
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/// Determine the event's ABI by parsing the AST
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fn derive_abi_event_from_fields(input: &DeriveInput) -> Result<Event, Error> {
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let event = Event {
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name: input.ident.to_string(),
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inputs: utils::derive_abi_inputs_from_fields(input, "EthEvent")?
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.into_iter()
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.map(|(name, kind)| EventParam { name, kind, indexed: false })
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.collect(),
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anonymous: false,
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};
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Ok(event)
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}
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fn parse_field_attributes(field: &Field) -> Result<(Option<String>, bool), Error> {
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let mut indexed = false;
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let mut topic_name = None;
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for a in field.attrs.iter() {
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if let AttrStyle::Outer = a.style {
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if let Ok(Meta::List(meta)) = a.parse_meta() {
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if meta.path.is_ident("ethevent") {
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for n in meta.nested.iter() {
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if let NestedMeta::Meta(meta) = n {
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match meta {
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Meta::Path(path) => {
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if path.is_ident("indexed") {
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indexed = true;
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} else {
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return Err(Error::new(
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path.span(),
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"unrecognized ethevent parameter",
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))
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}
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}
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Meta::List(meta) => {
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return Err(Error::new(
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meta.path.span(),
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"unrecognized ethevent parameter",
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))
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}
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Meta::NameValue(meta) => {
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if meta.path.is_ident("name") {
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if let Lit::Str(ref lit_str) = meta.lit {
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topic_name = Some(lit_str.value());
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} else {
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return Err(Error::new(
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meta.span(),
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"name attribute must be a string",
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))
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}
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}
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}
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}
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}
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}
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}
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}
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}
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}
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Ok((topic_name, indexed))
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}
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/// All the attributes the `EthEvent` macro supports
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#[derive(Default)]
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struct EthEventAttributes {
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name: Option<(String, Span)>,
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abi: Option<(String, Span)>,
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signature_hash: Option<(Vec<u8>, Span)>,
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anonymous: Option<(bool, Span)>,
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}
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/// extracts the attributes from the struct annotated with `EthEvent`
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fn parse_event_attributes(input: &DeriveInput) -> Result<EthEventAttributes, Error> {
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let mut result = EthEventAttributes::default();
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for a in input.attrs.iter() {
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if let AttrStyle::Outer = a.style {
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if let Ok(Meta::List(meta)) = a.parse_meta() {
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if meta.path.is_ident("ethevent") {
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for n in meta.nested.iter() {
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if let NestedMeta::Meta(meta) = n {
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match meta {
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Meta::Path(path) => {
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if let Some(name) = path.get_ident() {
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if &*name.to_string() == "anonymous" {
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if result.anonymous.is_none() {
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result.anonymous = Some((true, name.span()));
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continue
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} else {
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return Err(Error::new(
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name.span(),
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"anonymous already specified",
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))
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}
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}
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}
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return Err(Error::new(
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path.span(),
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"unrecognized ethevent parameter",
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))
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}
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Meta::List(meta) => {
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return Err(Error::new(
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meta.path.span(),
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"unrecognized ethevent parameter",
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))
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}
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Meta::NameValue(meta) => {
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if meta.path.is_ident("anonymous") {
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if let Lit::Bool(ref bool_lit) = meta.lit {
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if result.anonymous.is_none() {
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result.anonymous =
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Some((bool_lit.value, bool_lit.span()));
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} else {
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return Err(Error::new(
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meta.span(),
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"anonymous already specified",
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))
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}
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} else {
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return Err(Error::new(
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meta.span(),
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"name must be a string",
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))
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}
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} else if meta.path.is_ident("name") {
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if let Lit::Str(ref lit_str) = meta.lit {
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if result.name.is_none() {
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result.name =
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Some((lit_str.value(), lit_str.span()));
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} else {
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return Err(Error::new(
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meta.span(),
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"name already specified",
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))
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}
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} else {
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return Err(Error::new(
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meta.span(),
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"name must be a string",
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))
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}
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} else if meta.path.is_ident("abi") {
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if let Lit::Str(ref lit_str) = meta.lit {
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if result.abi.is_none() {
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result.abi =
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Some((lit_str.value(), lit_str.span()));
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} else {
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return Err(Error::new(
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meta.span(),
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"abi already specified",
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))
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}
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} else {
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return Err(Error::new(
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meta.span(),
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"abi must be a string",
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))
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}
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} else if meta.path.is_ident("signature") {
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if let Lit::Str(ref lit_str) = meta.lit {
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if result.signature_hash.is_none() {
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match Vec::from_hex(lit_str.value()) {
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Ok(sig) => {
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result.signature_hash =
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Some((sig, lit_str.span()))
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}
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Err(err) => {
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return Err(Error::new(
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meta.span(),
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format!(
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"Expected hex signature: {err:?}"
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),
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))
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}
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}
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} else {
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return Err(Error::new(
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meta.span(),
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"signature already specified",
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))
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}
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} else {
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return Err(Error::new(
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meta.span(),
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"signature must be a hex string",
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))
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}
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} else {
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return Err(Error::new(
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meta.span(),
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"unrecognized ethevent parameter",
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))
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}
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}
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}
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}
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}
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}
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}
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}
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}
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Ok(result)
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}
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