foundry_common/
abi.rs

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
//! ABI related helper functions.

use alloy_dyn_abi::{DynSolType, DynSolValue, FunctionExt, JsonAbiExt};
use alloy_json_abi::{Error, Event, Function, Param};
use alloy_primitives::{hex, Address, LogData};
use eyre::{Context, ContextCompat, Result};
use foundry_block_explorers::{contract::ContractMetadata, errors::EtherscanError, Client};
use foundry_config::Chain;
use std::{future::Future, pin::Pin};

pub fn encode_args<I, S>(inputs: &[Param], args: I) -> Result<Vec<DynSolValue>>
where
    I: IntoIterator<Item = S>,
    S: AsRef<str>,
{
    std::iter::zip(inputs, args)
        .map(|(input, arg)| coerce_value(&input.selector_type(), arg.as_ref()))
        .collect()
}

/// Given a function and a vector of string arguments, it proceeds to convert the args to alloy
/// [DynSolValue]s and then ABI encode them.
pub fn encode_function_args<I, S>(func: &Function, args: I) -> Result<Vec<u8>>
where
    I: IntoIterator<Item = S>,
    S: AsRef<str>,
{
    Ok(func.abi_encode_input(&encode_args(&func.inputs, args)?)?)
}

/// Given a function and a vector of string arguments, it proceeds to convert the args to alloy
/// [DynSolValue]s and encode them using the packed encoding.
pub fn encode_function_args_packed<I, S>(func: &Function, args: I) -> Result<Vec<u8>>
where
    I: IntoIterator<Item = S>,
    S: AsRef<str>,
{
    let params: Vec<Vec<u8>> = std::iter::zip(&func.inputs, args)
        .map(|(input, arg)| coerce_value(&input.selector_type(), arg.as_ref()))
        .collect::<Result<Vec<_>>>()?
        .into_iter()
        .map(|v| v.abi_encode_packed())
        .collect();

    Ok(params.concat())
}

/// Decodes the calldata of the function
pub fn abi_decode_calldata(
    sig: &str,
    calldata: &str,
    input: bool,
    fn_selector: bool,
) -> Result<Vec<DynSolValue>> {
    let func = get_func(sig)?;
    let calldata = hex::decode(calldata)?;

    let mut calldata = calldata.as_slice();
    // If function selector is prefixed in "calldata", remove it (first 4 bytes)
    if input && fn_selector && calldata.len() >= 4 {
        calldata = &calldata[4..];
    }

    let res = if input {
        func.abi_decode_input(calldata, false)
    } else {
        func.abi_decode_output(calldata, false)
    }?;

    // in case the decoding worked but nothing was decoded
    if res.is_empty() {
        eyre::bail!("no data was decoded")
    }

    Ok(res)
}

/// Given a function signature string, it tries to parse it as a `Function`
pub fn get_func(sig: &str) -> Result<Function> {
    Function::parse(sig).wrap_err("could not parse function signature")
}

/// Given an event signature string, it tries to parse it as a `Event`
pub fn get_event(sig: &str) -> Result<Event> {
    Event::parse(sig).wrap_err("could not parse event signature")
}

/// Given an error signature string, it tries to parse it as a `Error`
pub fn get_error(sig: &str) -> Result<Error> {
    Error::parse(sig).wrap_err("could not parse event signature")
}

/// Given an event without indexed parameters and a rawlog, it tries to return the event with the
/// proper indexed parameters. Otherwise, it returns the original event.
pub fn get_indexed_event(mut event: Event, raw_log: &LogData) -> Event {
    if !event.anonymous && raw_log.topics().len() > 1 {
        let indexed_params = raw_log.topics().len() - 1;
        let num_inputs = event.inputs.len();
        let num_address_params = event.inputs.iter().filter(|p| p.ty == "address").count();

        event.inputs.iter_mut().enumerate().for_each(|(index, param)| {
            if param.name.is_empty() {
                param.name = format!("param{index}");
            }
            if num_inputs == indexed_params ||
                (num_address_params == indexed_params && param.ty == "address")
            {
                param.indexed = true;
            }
        })
    }
    event
}

/// Given a function name, address, and args, tries to parse it as a `Function` by fetching the
/// abi from etherscan. If the address is a proxy, fetches the ABI of the implementation contract.
pub async fn get_func_etherscan(
    function_name: &str,
    contract: Address,
    args: &[String],
    chain: Chain,
    etherscan_api_key: &str,
) -> Result<Function> {
    let client = Client::new(chain, etherscan_api_key)?;
    let source = find_source(client, contract).await?;
    let metadata = source.items.first().wrap_err("etherscan returned empty metadata")?;

    let mut abi = metadata.abi()?;
    let funcs = abi.functions.remove(function_name).unwrap_or_default();

    for func in funcs {
        let res = encode_function_args(&func, args);
        if res.is_ok() {
            return Ok(func)
        }
    }

    Err(eyre::eyre!("Function not found in abi"))
}

/// If the code at `address` is a proxy, recurse until we find the implementation.
pub fn find_source(
    client: Client,
    address: Address,
) -> Pin<Box<dyn Future<Output = Result<ContractMetadata>>>> {
    Box::pin(async move {
        trace!(%address, "find Etherscan source");
        let source = client.contract_source_code(address).await?;
        let metadata = source.items.first().wrap_err("Etherscan returned no data")?;
        if metadata.proxy == 0 {
            Ok(source)
        } else {
            let implementation = metadata.implementation.unwrap();
            sh_println!(
                "Contract at {address} is a proxy, trying to fetch source at {implementation}..."
            )?;
            match find_source(client, implementation).await {
                impl_source @ Ok(_) => impl_source,
                Err(e) => {
                    let err = EtherscanError::ContractCodeNotVerified(address).to_string();
                    if e.to_string() == err {
                        error!(%err);
                        Ok(source)
                    } else {
                        Err(e)
                    }
                }
            }
        }
    })
}

/// Helper function to coerce a value to a [DynSolValue] given a type string
pub fn coerce_value(ty: &str, arg: &str) -> Result<DynSolValue> {
    let ty = DynSolType::parse(ty)?;
    Ok(DynSolType::coerce_str(&ty, arg)?)
}

#[cfg(test)]
mod tests {
    use super::*;
    use alloy_dyn_abi::EventExt;
    use alloy_primitives::{B256, U256};

    #[test]
    fn test_get_func() {
        let func = get_func("function foo(uint256 a, uint256 b) returns (uint256)");
        assert!(func.is_ok());
        let func = func.unwrap();
        assert_eq!(func.name, "foo");
        assert_eq!(func.inputs.len(), 2);
        assert_eq!(func.inputs[0].ty, "uint256");
        assert_eq!(func.inputs[1].ty, "uint256");

        // Stripped down function, which [Function] can parse.
        let func = get_func("foo(bytes4 a, uint8 b)(bytes4)");
        assert!(func.is_ok());
        let func = func.unwrap();
        assert_eq!(func.name, "foo");
        assert_eq!(func.inputs.len(), 2);
        assert_eq!(func.inputs[0].ty, "bytes4");
        assert_eq!(func.inputs[1].ty, "uint8");
        assert_eq!(func.outputs[0].ty, "bytes4");
    }

    #[test]
    fn test_indexed_only_address() {
        let event = get_event("event Ev(address,uint256,address)").unwrap();

        let param0 = B256::random();
        let param1 = vec![3; 32];
        let param2 = B256::random();
        let log = LogData::new_unchecked(vec![event.selector(), param0, param2], param1.into());
        let event = get_indexed_event(event, &log);

        assert_eq!(event.inputs.len(), 3);

        // Only the address fields get indexed since total_params > num_indexed_params
        let parsed = event.decode_log(&log, false).unwrap();

        assert_eq!(event.inputs.iter().filter(|param| param.indexed).count(), 2);
        assert_eq!(parsed.indexed[0], DynSolValue::Address(Address::from_word(param0)));
        assert_eq!(parsed.body[0], DynSolValue::Uint(U256::from_be_bytes([3; 32]), 256));
        assert_eq!(parsed.indexed[1], DynSolValue::Address(Address::from_word(param2)));
    }

    #[test]
    fn test_indexed_all() {
        let event = get_event("event Ev(address,uint256,address)").unwrap();

        let param0 = B256::random();
        let param1 = vec![3; 32];
        let param2 = B256::random();
        let log = LogData::new_unchecked(
            vec![event.selector(), param0, B256::from_slice(&param1), param2],
            vec![].into(),
        );
        let event = get_indexed_event(event, &log);

        assert_eq!(event.inputs.len(), 3);

        // All parameters get indexed since num_indexed_params == total_params
        assert_eq!(event.inputs.iter().filter(|param| param.indexed).count(), 3);
        let parsed = event.decode_log(&log, false).unwrap();

        assert_eq!(parsed.indexed[0], DynSolValue::Address(Address::from_word(param0)));
        assert_eq!(parsed.indexed[1], DynSolValue::Uint(U256::from_be_bytes([3; 32]), 256));
        assert_eq!(parsed.indexed[2], DynSolValue::Address(Address::from_word(param2)));
    }
}