emerald-vault-core 0.26.6

/*
Copyright 2019 ETCDEV GmbH

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
//! # Contract
#[allow(dead_code)]
mod error;

pub use self::error::Error;
use ethabi::spec::param_type::{ParamType, Reader};
use ethabi::token::{LenientTokenizer, Token, Tokenizer};
use ethabi::{Encoder, Function, Interface};
use hex;
use std::fmt;

/// Contract specification
#[derive(Clone, Debug, Deserialize)]
pub struct Contract {
    abi: Interface,
}

impl Contract {
    /// Try to convert deserialized vector to Contract ABI.
    ///
    /// # Arguments
    ///
    /// * `DATA` - A byte slice
    ///
    pub fn try_from(data: &[u8]) -> Result<Self, Error> {
        let abi = Interface::load(data)?;
        Ok(Contract { abi })
    }

    /// Returns specification of contract function given the function name.
    pub fn get_function(&self, name: String) -> Option<Function> {
        match self.abi.function(name) {
            Some(f) => Some(Function::new(f)),
            _ => None,
        }
    }

    /// Encode ABI function call with input params
    pub fn serialize_function_call(
        &self,
        name: String,
        params: Vec<Token>,
    ) -> Result<Vec<u8>, Error> {
        let f = self.get_function(name).unwrap();
        f.encode_call(params).map_err(From::from)
    }

    /// Encode ABI input params to hex string
    pub fn serialize_params(types: &[String], values: Vec<String>) -> Result<String, Error> {
        let types: Result<Vec<ParamType>, _> = types.iter().map(|s| Reader::read(s)).collect();

        let types = r#try!(types);

        let params: Vec<_> = types.into_iter().zip(values.into_iter()).collect();

        let tokens = params
            .iter()
            .map(|&(ref param, ref value)| LenientTokenizer::tokenize(param, value))
            .collect::<Result<_, _>>()?;

        let result = Encoder::encode(tokens);

        Ok(hex::encode(result))
    }
}

impl fmt::Display for Contract {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "{:?}", self.abi)
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use ethabi::spec::{Function as FunctionInterface, Param, ParamType};

    #[test]
    fn should_display_contract_abi() {
        let c = b"[{\"constant\":true,\"inputs\":[],\"name\":\"name\",\"outputs\":[{\"name\":\"\",\
                 \"type\":\"string\"}],\"payable\":false,\"type\":\"function\"}]";
        let contract = Contract::try_from(c).unwrap();
        format!("{}", contract);
    }

    #[test]
    fn should_return_correct_function() {
        let c = b"[{\"constant\":true,\"inputs\":[{\"name\":\"\",\"type\":\"address\"}],\"name\":\
                 \"balanceOf\",\"outputs\":[{\"name\":\"\",\"type\":\"uint256\"}],\"payable\":\
                 false,\"type\":\"function\"},{\"constant\":true,\"inputs\":[],\"name\":\"name\",\
                 \"outputs\":[{\"name\":\"\",\"type\":\"string\"}],\"payable\":false,\"type\":\
                 \"function\"}]";
        let interface = FunctionInterface {
            name: "balanceOf".to_owned(),
            inputs: vec![Param {
                name: "".to_owned(),
                kind: ParamType::Address,
            }],
            outputs: vec![Param {
                name: "a".to_owned(),
                kind: ParamType::Uint(256),
            }],
        };
        let contract = Contract::try_from(c).unwrap();
        let f = contract.get_function("balanceOf".to_string()).unwrap();
        assert_eq!(f.input_params(), Function::new(interface).input_params());
    }
}