feat: sol! contracts (#77)

* feat: `sol!` contracts

* chore: clippy

* docs: add note about parser design, leniency

* test: bless tests after updating to syn 2.0.19

* typo

* test: bless new test

crates/sol-macro/src/expand/attr.rs

@@ -0,0 +1,9 @@
+use syn::Attribute;
+
+pub(crate) fn docs(attrs: &[Attribute]) -> impl Iterator<Item = &Attribute> {
+    attrs.iter().filter(|attr| attr.path().is_ident("doc"))
+}
+
+pub(crate) fn derives(attrs: &[Attribute]) -> impl Iterator<Item = &Attribute> {
+    attrs.iter().filter(|attr| attr.path().is_ident("derive"))
+}

crates/sol-macro/src/expand/mod.rs

@@ -1,13 +1,15 @@
 //! Functions which generate Rust code from the Solidity AST.
 
 use ast::{
-    File, Item, ItemError, ItemFunction, ItemStruct, ItemUdt, Parameters, SolIdent, Type,
-    VariableDeclaration, Visit,
+    File, Item, ItemContract, ItemError, ItemFunction, ItemStruct, ItemUdt, Parameters, SolIdent,
+    Type, VariableDeclaration, Visit,
 };
 use proc_macro2::{Ident, Span, TokenStream};
 use quote::{format_ident, quote, IdentFragment};
 use std::{collections::HashMap, fmt::Write};
-use syn::{Error, Result, Token};
+use syn::{parse_quote, Attribute, Error, Result, Token};
+
+mod attr;
 
 mod r#type;
 pub use r#type::expand_type;
@@ -76,13 +78,180 @@ impl<'ast> ExpCtxt<'ast> {
 
     fn expand_item(&self, item: &Item) -> Result<TokenStream> {
         match item {
+            Item::Contract(contract) => self.expand_contract(contract),
             Item::Error(error) => self.expand_error(error),
             Item::Function(function) => self.expand_function(function),
             Item::Struct(s) => self.expand_struct(s),
             Item::Udt(udt) => self.expand_udt(udt),
         }
     }
 
+    fn expand_contract(&self, contract: &ItemContract) -> Result<TokenStream> {
+        let ItemContract {
+            attrs, name, body, ..
+        } = contract;
+
+        let mut functions = Vec::with_capacity(contract.body.len());
+        let mut errors = Vec::with_capacity(contract.body.len());
+        let mut item_tokens = TokenStream::new();
+        let d_attrs: Vec<Attribute> = attr::derives(attrs).cloned().collect();
+        for item in body {
+            match item {
+                Item::Function(function) => functions.push(function),
+                Item::Error(error) => errors.push(error),
+                _ => {}
+            }
+            item_tokens.extend(quote!(#(#d_attrs)*));
+            item_tokens.extend(self.expand_item(item)?);
+        }
+
+        let functions_enum = if functions.len() > 1 {
+            let mut attrs = d_attrs.clone();
+            let doc_str = format!("Container for all the [`{name}`] function calls.");
+            attrs.push(parse_quote!(#[doc = #doc_str]));
+            Some(self.expand_functions_enum(name, functions, &attrs))
+        } else {
+            None
+        };
+
+        let errors_enum = if errors.len() > 1 {
+            let mut attrs = d_attrs;
+            let doc_str = format!("Container for all the [`{name}`] custom errors.");
+            attrs.push(parse_quote!(#[doc = #doc_str]));
+            Some(self.expand_errors_enum(name, errors, &attrs))
+        } else {
+            None
+        };
+
+        let mod_attrs = attr::docs(attrs);
+        let tokens = quote! {
+            #(#mod_attrs)*
+            #[allow(non_camel_case_types, non_snake_case, clippy::style)]
+            pub mod #name {
+                #item_tokens
+                #functions_enum
+                #errors_enum
+            }
+        };
+        Ok(tokens)
+    }
+
+    fn expand_functions_enum(
+        &self,
+        name: &SolIdent,
+        functions: Vec<&ItemFunction>,
+        attrs: &[Attribute],
+    ) -> TokenStream {
+        let name = format_ident!("{name}Calls");
+        let variants: Vec<_> = functions
+            .iter()
+            .map(|f| self.function_name_ident(f).0)
+            .collect();
+        let types: Vec<_> = variants.iter().map(|name| self.call_name(name)).collect();
+        let min_data_len = functions
+            .iter()
+            .map(|function| self.min_data_size(&function.arguments))
+            .max()
+            .unwrap();
+        let trt = Ident::new("SolCall", Span::call_site());
+        self.expand_call_like_enum(name, &variants, &types, min_data_len, trt, attrs)
+    }
+
+    fn expand_errors_enum(
+        &self,
+        name: &SolIdent,
+        errors: Vec<&ItemError>,
+        attrs: &[Attribute],
+    ) -> TokenStream {
+        let name = format_ident!("{name}Errors");
+        let variants: Vec<_> = errors.iter().map(|error| error.name.0.clone()).collect();
+        let min_data_len = errors
+            .iter()
+            .map(|error| self.min_data_size(&error.fields))
+            .max()
+            .unwrap();
+        let trt = Ident::new("SolError", Span::call_site());
+        self.expand_call_like_enum(name, &variants, &variants, min_data_len, trt, attrs)
+    }
+
+    fn expand_call_like_enum(
+        &self,
+        name: Ident,
+        variants: &[Ident],
+        types: &[Ident],
+        min_data_len: usize,
+        trt: Ident,
+        attrs: &[Attribute],
+    ) -> TokenStream {
+        assert_eq!(variants.len(), types.len());
+        let name_s = name.to_string();
+        let count = variants.len();
+        let min_data_len = min_data_len.min(4);
+        quote! {
+            #(#attrs)*
+            pub enum #name {#(
+                #variants(#types),
+            )*}
+
+            // TODO: Implement these functions using traits?
+            #[automatically_derived]
+            impl #name {
+                /// The number of variants.
+                pub const COUNT: usize = #count;
+
+                // no decode_raw is possible because we need the selector to know which variant to
+                // decode into
+
+                /// ABI-decodes the given data into one of the variants of `self`.
+                pub fn decode(data: &[u8], validate: bool) -> ::alloy_sol_types::Result<Self> {
+                    if data.len() >= #min_data_len {
+                        // TODO: Replace with `data.split_array_ref` once it's stable
+                        let (selector, data) = data.split_at(4);
+                        let selector: &[u8; 4] =
+                            ::core::convert::TryInto::try_into(selector).expect("unreachable");
+                        match *selector {
+                            #(<#types as ::alloy_sol_types::#trt>::SELECTOR => {
+                                return <#types as ::alloy_sol_types::#trt>::decode_raw(data, validate)
+                                    .map(Self::#variants)
+                            })*
+                            _ => {}
+                        }
+                    }
+                    ::core::result::Result::Err(::alloy_sol_types::Error::type_check_fail(
+                        data,
+                        #name_s,
+                    ))
+                }
+
+                /// ABI-encodes `self` into the given buffer.
+                pub fn encode_raw(&self, out: &mut Vec<u8>) {
+                    match self {#(
+                        Self::#variants(inner) =>
+                            <#types as ::alloy_sol_types::#trt>::encode_raw(inner, out),
+                    )*}
+                }
+
+                /// ABI-encodes `self` into the given buffer.
+                #[inline]
+                pub fn encode(&self) -> Vec<u8> {
+                    match self {#(
+                        Self::#variants(inner) =>
+                            <#types as ::alloy_sol_types::#trt>::encode(inner),
+                    )*}
+                }
+            }
+
+            #(
+                #[automatically_derived]
+                impl From<#types> for #name {
+                    fn from(value: #types) -> Self {
+                        Self::#variants(value)
+                    }
+                }
+            )*
+        }
+    }
+
     fn expand_error(&self, error: &ItemError) -> Result<TokenStream> {
         let ItemError {
             fields,
@@ -344,7 +513,7 @@ impl<'ast> ExpCtxt<'ast> {
                 ty.visit_mut(|ty| {
                     let ty @ Type::Custom(_) = ty else { return };
                     let Type::Custom(name) = &*ty else { unreachable!() };
-                    let Some(resolved) = self.custom_types.get(name) else { return };
+                    let Some(resolved) = self.custom_types.get(name.last_tmp()) else { return };
                     ty.clone_from(resolved);
                     any = true;
                 });
@@ -431,6 +600,15 @@ impl<'ast> ExpCtxt<'ast> {
         }
     }
 
+    /// Returns the name of the function, adjusted for overloads.
+    fn function_name_ident(&self, function: &ItemFunction) -> SolIdent {
+        let sig = self.function_signature(function);
+        match self.function_overloads.get(&sig) {
+            Some(name) => SolIdent::new_spanned(name, function.name.span()),
+            None => function.name.clone(),
+        }
+    }
+
     fn call_name(&self, function_name: impl IdentFragment + std::fmt::Display) -> Ident {
         format_ident!("{function_name}Call")
     }
@@ -464,7 +642,7 @@ impl<'ast> ExpCtxt<'ast> {
         let mut errors = Vec::new();
         params.visit_types(|ty| {
             if let Type::Custom(name) = ty {
-                if !self.custom_types.contains_key(name) {
+                if !self.custom_types.contains_key(name.last_tmp()) {
                     let e = syn::Error::new(name.span(), "unresolved type");
                     errors.push(e);
                 }

crates/sol-macro/src/expand/type.rs

@@ -1,5 +1,5 @@
 use super::ExpCtxt;
-use ast::{Item, SolArray, SolIdent, Type};
+use ast::{Item, Parameters, SolArray, SolPath, Type};
 use proc_macro2::{Literal, TokenStream};
 use quote::{quote, quote_spanned, ToTokens};
 use std::{fmt, num::NonZeroU16};
@@ -74,20 +74,29 @@ fn rec_expand_type(ty: &Type, tokens: &mut TokenStream) {
 }
 
 impl ExpCtxt<'_> {
-    fn get_item(&self, name: &SolIdent) -> &Item {
+    fn get_item(&self, name: &SolPath) -> &Item {
+        let name = name.last_tmp();
         match self.all_items.iter().find(|item| item.name() == name) {
             Some(item) => item,
             None => panic!("unresolved item: {name}"),
         }
     }
 
-    fn custom_type(&self, name: &SolIdent) -> &Type {
-        match self.custom_types.get(name) {
+    fn custom_type(&self, name: &SolPath) -> &Type {
+        match self.custom_types.get(name.last_tmp()) {
             Some(item) => item,
             None => panic!("unresolved item: {name}"),
         }
     }
 
+    pub(super) fn min_data_size<P>(&self, params: &Parameters<P>) -> usize {
+        params
+            .iter()
+            .map(|param| self.type_base_data_size(&param.ty))
+            .max()
+            .unwrap_or(0)
+    }
+
     /// Recursively calculates the base ABI-encoded size of `self` in bytes.
     ///
     /// That is, the minimum number of bytes required to encode `self` without
@@ -127,7 +136,7 @@ impl ExpCtxt<'_> {
                     .map(|ty| self.type_base_data_size(ty))
                     .sum(),
                 Item::Udt(udt) => self.type_base_data_size(&udt.ty),
-                Item::Error(_) | Item::Function(_) => unreachable!(),
+                Item::Contract(_) | Item::Error(_) | Item::Function(_) => unreachable!(),
             },
         }
     }
@@ -182,7 +191,7 @@ impl ExpCtxt<'_> {
             Type::Custom(name) => match self.get_item(name) {
                 Item::Struct(strukt) => self.params_data_size(&strukt.fields, Some(field)),
                 Item::Udt(udt) => self.type_data_size(&udt.ty, field),
-                Item::Error(_) | Item::Function(_) => unreachable!(),
+                Item::Contract(_) | Item::Error(_) | Item::Function(_) => unreachable!(),
             },
         }
     }

crates/sol-types/src/types/call.rs

@@ -35,8 +35,7 @@ pub trait SolCall: Sized {
     /// selector.
     #[inline]
     fn decode_raw(data: &[u8], validate: bool) -> Result<Self> {
-        let tuple = <Self::Tuple as SolType>::decode(data, validate)?;
-        Ok(Self::from_rust(tuple))
+        <Self::Tuple as SolType>::decode(data, validate).map(Self::from_rust)
     }
 
     /// ABI decode this call's arguments from the given slice, **with** the
@@ -52,6 +51,7 @@ pub trait SolCall: Sized {
     /// ABI encode the call to the given buffer **without** its selector.
     #[inline]
     fn encode_raw(&self, out: &mut Vec<u8>) {
+        out.reserve(self.data_size());
         out.extend(<Self::Tuple as SolType>::encode(self.to_rust()));
     }
 

crates/sol-types/tests/doc_contracts.rs

@@ -1,4 +1,42 @@
+use alloy_primitives::{Address, U256};
+use alloy_sol_types::{sol, SolCall};
+use hex_literal::hex;
+
+sol! {
+    /// Interface of the ERC20 standard as defined in [the EIP].
+    ///
+    /// [the EIP]: https://eips.ethereum.org/EIPS/eip-20
+    #[derive(Debug, PartialEq)]
+    interface IERC20 {
+        // TODO: Events
+        // event Transfer(address indexed from, address indexed to, uint256 value);
+        // event Approval(address indexed owner, address indexed spender, uint256 value);
+
+        function totalSupply() external view returns (uint256);
+        function balanceOf(address account) external view returns (uint256);
+        function transfer(address to, uint256 amount) external returns (bool);
+        function allowance(address owner, address spender) external view returns (uint256);
+        function approve(address spender, uint256 amount) external returns (bool);
+        function transferFrom(address from, address to, uint256 amount) external returns (bool);
+    }
+}
+
 #[test]
 fn contracts() {
-    // TODO
+    // random mainnet ERC20 transfer
+    // https://etherscan.io/tx/0x947332ff624b5092fb92e8f02cdbb8a50314e861a4b39c29a286b3b75432165e
+    let data = hex!(
+        "a9059cbb"
+        "0000000000000000000000008bc47be1e3abbaba182069c89d08a61fa6c2b292"
+        "0000000000000000000000000000000000000000000000000000000253c51700"
+    );
+    let expected = IERC20::transferCall {
+        to: Address::from(hex!("8bc47be1e3abbaba182069c89d08a61fa6c2b292")),
+        amount: U256::from(9995360000_u64),
+    };
+
+    assert_eq!(data[..4], IERC20::transferCall::SELECTOR);
+    let decoded = IERC20::IERC20Calls::decode(&data, true).unwrap();
+    assert_eq!(decoded, IERC20::IERC20Calls::transfer(expected));
+    assert_eq!(decoded.encode(), data);
 }

crates/sol-types/tests/ui/contract.rs

@@ -0,0 +1,21 @@
+use alloy_sol_types::sol;
+
+sol! {
+    contract C {
+        contract Nested {}
+    }
+}
+
+sol! {
+    interface C {
+        library Nested {}
+    }
+}
+
+sol! {
+    abstract contract C {
+        interface Nested {}
+    }
+}
+
+fn main() {}