contract.rs

#![deny(missing_docs)]
mod common;
mod events;
mod methods;
mod structs;
mod types;

use super::{util, Abigen};
use crate::{contract::structs::InternalStructs, rawabi::RawAbi};
use anyhow::{anyhow, Context as _, Result};
use ethers_core::{
    abi::{Abi, AbiParser},
    macros::{ethers_contract_crate, ethers_core_crate, ethers_providers_crate},
};

use crate::contract::methods::MethodAlias;
use proc_macro2::{Ident, Literal, TokenStream};
use quote::quote;
use serde::Deserialize;
use std::collections::BTreeMap;
use syn::Path;

/// The result of `Context::expand`
#[derive(Debug)]
pub struct ExpandedContract {
    /// The name of the contract module
    pub module: Ident,
    /// The contract module's imports
    pub imports: TokenStream,
    /// Contract, Middle related implementations
    pub contract: TokenStream,
    /// All event impls of the contract
    pub events: TokenStream,
    /// All contract call struct related types
    pub call_structs: TokenStream,
    /// The contract's internal structs
    pub abi_structs: TokenStream,
}

impl ExpandedContract {
    /// Merges everything into a single module
    pub fn into_tokens(self) -> TokenStream {
        let ExpandedContract { module, imports, contract, events, call_structs, abi_structs } =
            self;
        quote! {
           // export all the created data types
            pub use #module::*;

            #[allow(clippy::too_many_arguments)]
            mod #module {
                #imports
                #contract
                #events
                #call_structs
                #abi_structs
            }
        }
    }
}

/// Internal shared context for generating smart contract bindings.
pub struct Context {
    /// The ABI string pre-parsing.
    abi_str: Literal,

    /// The parsed ABI.
    abi: Abi,

    /// The parser used for human readable format
    abi_parser: AbiParser,

    /// Contains all the solidity structs extracted from the JSON ABI.
    internal_structs: InternalStructs,

    /// Was the ABI in human readable format?
    human_readable: bool,

    /// The contract name as an identifier.
    contract_name: Ident,

    /// Manually specified method aliases.
    method_aliases: BTreeMap<String, MethodAlias>,

    /// Derives added to event structs and enums.
    event_derives: Vec<Path>,

    /// Manually specified event aliases.
    event_aliases: BTreeMap<String, Ident>,
}

impl Context {
    /// Expands the whole rust contract
    pub fn expand(&self) -> Result<ExpandedContract> {
        let name = &self.contract_name;
        let name_mod =
            util::ident(&format!("{}_mod", self.contract_name.to_string().to_lowercase()));

        let abi_name = super::util::safe_ident(&format!("{}_ABI", name.to_string().to_uppercase()));

        // 0. Imports
        let imports = common::imports(&name.to_string());

        // 1. Declare Contract struct
        let struct_decl = common::struct_declaration(self, &abi_name);

        // 2. Declare events structs & impl FromTokens for each event
        let events_decl = self.events_declaration()?;

        // 3. impl block for the event functions
        let contract_events = self.event_methods()?;

        // 4. impl block for the contract methods and their corresponding types
        let (contract_methods, call_structs) = self.methods_and_call_structs()?;

        // 5. Declare the structs parsed from the human readable abi
        let abi_structs_decl = self.abi_structs()?;

        let ethers_core = ethers_core_crate();
        let ethers_contract = ethers_contract_crate();
        let ethers_providers = ethers_providers_crate();

        let contract = quote! {
                #struct_decl

                impl<'a, M: #ethers_providers::Middleware> #name<M> {
                    /// Creates a new contract instance with the specified `ethers`
                    /// client at the given `Address`. The contract derefs to a `ethers::Contract`
                    /// object
                    pub fn new<T: Into<#ethers_core::types::Address>>(address: T, client: ::std::sync::Arc<M>) -> Self {
                        let contract = #ethers_contract::Contract::new(address.into(), #abi_name.clone(), client);
                        Self(contract)
                    }

                    // TODO: Implement deployment.

                    #contract_methods

                    #contract_events
                }
        };

        Ok(ExpandedContract {
            module: name_mod,
            imports,
            contract,
            events: events_decl,
            call_structs,
            abi_structs: abi_structs_decl,
        })
    }

    /// Create a context from the code generation arguments.
    pub fn from_abigen(args: Abigen) -> Result<Self> {
        // get the actual ABI string
        let abi_str =
            args.abi_source.get().map_err(|e| anyhow!("failed to get ABI JSON: {}", e))?;

        let (abi, human_readable, abi_parser) = parse_abi(&abi_str)?;
        let abi_str = serde_json::to_string(&abi).context("fail to serialize abi to json")?;

        // try to extract all the solidity structs from the normal JSON ABI
        // we need to parse the json abi again because we need the internalType fields which are
        // omitted by ethabi. If the ABI was defined as human readable we use the `internal_structs`
        // from the Abi Parser
        let internal_structs = if human_readable {
            let mut internal_structs = InternalStructs::default();
            // the types in the abi_parser are already valid rust types so simply clone them to make
            // it consistent with the `RawAbi` variant
            internal_structs
                .rust_type_names
                .extend(abi_parser.function_params.values().map(|ty| (ty.clone(), ty.clone())));
            internal_structs.function_params = abi_parser.function_params.clone();
            internal_structs.outputs = abi_parser.outputs.clone();

            internal_structs
        } else {
            serde_json::from_str::<RawAbi>(&abi_str)
                .ok()
                .map(InternalStructs::new)
                .unwrap_or_default()
        };

        let contract_name = util::ident(&args.contract_name);

        // NOTE: We only check for duplicate signatures here, since if there are
        //   duplicate aliases, the compiler will produce a warning because a
        //   method will be re-defined.
        let mut method_aliases = BTreeMap::new();
        for (signature, alias) in args.method_aliases.into_iter() {
            let alias = MethodAlias {
                function_name: util::safe_ident(&alias),
                struct_name: util::safe_pascal_case_ident(&alias),
            };

            if method_aliases.insert(signature.clone(), alias).is_some() {
                return Err(anyhow!("duplicate method signature '{}' in method aliases", signature,))
            }
        }

        let mut event_aliases = BTreeMap::new();
        for (signature, alias) in args.event_aliases.into_iter() {
            let alias = syn::parse_str(&alias)?;
            event_aliases.insert(signature, alias);
        }

        let event_derives = args
            .event_derives
            .iter()
            .map(|derive| syn::parse_str::<Path>(derive))
            .collect::<Result<Vec<_>, _>>()
            .context("failed to parse event derives")?;

        Ok(Context {
            abi,
            human_readable,
            abi_str: Literal::string(&abi_str),
            abi_parser,
            internal_structs,
            contract_name,
            method_aliases,
            event_derives,
            event_aliases,
        })
    }

    /// The internal abi struct mapping table
    pub fn internal_structs(&self) -> &InternalStructs {
        &self.internal_structs
    }

    /// The internal mutable abi struct mapping table
    pub fn internal_structs_mut(&mut self) -> &mut InternalStructs {
        &mut self.internal_structs
    }
}

/// Parse the abi via `Source::parse` and return if the abi defined as human readable
fn parse_abi(abi_str: &str) -> Result<(Abi, bool, AbiParser)> {
    let mut abi_parser = AbiParser::default();
    let res = if let Ok(abi) = abi_parser.parse_str(abi_str) {
        (abi, true, abi_parser)
    } else {
        #[derive(Deserialize)]
        struct Contract {
            abi: Abi,
        }
        // a best-effort coercion of an ABI or an artifact JSON into an artifact JSON.
        let contract: Contract = if abi_str.trim_start().starts_with('[') {
            serde_json::from_str(&format!(r#"{{"abi":{}}}"#, abi_str.trim()))?
        } else {
            serde_json::from_str::<Contract>(abi_str)?
        };

        (contract.abi, false, abi_parser)
    };
    Ok(res)
}


#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_abi_str_is_human_readable() {
        let abi_str = r#"{
            "abi": [
              {
                "type": "function",
                "name": "allowance",
                "inputs": [
                  {
                    "internalType": "address",
                    "name": "owner",
                    "type": "address"
                  },
                  {
                    "internalType": "address",
                    "name": "spender",
                    "type": "address"
                  }
                ],
                "outputs": [
                  {
                    "internalType": "uint256",
                    "name": "",
                    "type": "uint256"
                  }
                ],
                "constant": false,
                "stateMutability": "view"
              },
              {
                "type": "function",
                "name": "approve",
                "inputs": [
                  {
                    "internalType": "address",
                    "name": "spender",
                    "type": "address"
                  },
                  {
                    "internalType": "uint256",
                    "name": "amount",
                    "type": "uint256"
                  }
                ],
                "outputs": [
                  {
                    "internalType": "bool",
                    "name": "",
                    "type": "bool"
                  }
                ],
                "constant": false,
                "stateMutability": "nonpayable"
              }
            ],
            "bin": "0x",
            "bin-runtime": "0x"
          }"#;

        let (abi, _, _) = parse_abi(&abi_str).unwrap();
        let abi_str = serde_json::to_string(&abi).context("fail to serialize abi to json").unwrap();

        assert!(&abi_str.starts_with('['));
    }
}