use std::collections::HashMap;
use tiny_keccak::keccak256;
use signature::long_signature;
use {
Log, Hash, RawLog, LogParam, RawTopicFilter, TopicFilter,
Topic, ParamType, EventParam, encode, decode, Token,
Result, ErrorKind
};
#[derive(Clone, Debug, PartialEq, Deserialize)]
pub struct Event {
pub name: String,
pub inputs: Vec<EventParam>,
pub anonymous: bool,
}
impl Event {
fn params_names(&self) -> Vec<String> {
self.inputs.iter()
.map(|p| p.name.clone())
.collect()
}
fn param_types(&self) -> Vec<ParamType> {
self.inputs.iter()
.map(|p| p.kind.clone())
.collect()
}
fn indexed_params(&self, indexed: bool) -> Vec<EventParam> {
self.inputs.iter()
.filter(|p| p.indexed == indexed)
.cloned()
.collect()
}
pub fn signature(&self) -> Hash {
long_signature(&self.name, &self.param_types())
}
pub fn filter(&self, raw: RawTopicFilter) -> Result<TopicFilter> {
fn convert_token(token: Token, kind: &ParamType) -> Result<Hash> {
if !token.type_check(kind) {
return Err(ErrorKind::InvalidData.into());
}
let encoded = encode(&[token]);
if encoded.len() == 32 {
let mut data = [0u8; 32];
data.copy_from_slice(&encoded);
Ok(data.into())
} else {
Ok(keccak256(&encoded).into())
}
}
fn convert_topic(topic: Topic<Token>, kind: Option<&ParamType>) -> Result<Topic<Hash>> {
match topic {
Topic::Any => Ok(Topic::Any),
Topic::OneOf(tokens) => match kind {
None => Err(ErrorKind::InvalidData.into()),
Some(kind) => {
let topics = tokens.into_iter()
.map(|token| convert_token(token, kind))
.collect::<Result<Vec<_>>>()?;
Ok(Topic::OneOf(topics))
}
},
Topic::This(token) => match kind {
None => Err(ErrorKind::InvalidData.into()),
Some(kind) => Ok(Topic::This(convert_token(token, kind)?)),
}
}
}
let kinds: Vec<_> = self.indexed_params(true).into_iter().map(|param| param.kind).collect();
let result = if self.anonymous {
TopicFilter {
topic0: convert_topic(raw.topic0, kinds.get(0))?,
topic1: convert_topic(raw.topic1, kinds.get(1))?,
topic2: convert_topic(raw.topic2, kinds.get(2))?,
topic3: Topic::Any,
}
} else {
TopicFilter {
topic0: Topic::This(self.signature()),
topic1: convert_topic(raw.topic0, kinds.get(0))?,
topic2: convert_topic(raw.topic1, kinds.get(1))?,
topic3: convert_topic(raw.topic2, kinds.get(2))?,
}
};
Ok(result)
}
fn convert_topic_param_type(&self, kind: &ParamType) -> ParamType {
match kind {
ParamType::String
| ParamType::Bytes
| ParamType::Array(_)
| ParamType::FixedArray(_, _) => ParamType::FixedBytes(32),
_ => kind.clone()
}
}
pub fn parse_log(&self, log: RawLog) -> Result<Log> {
let topics = log.topics;
let data = log.data;
let topics_len = topics.len();
let topic_params = self.indexed_params(true);
let data_params = self.indexed_params(false);
let to_skip = if self.anonymous {
0
} else {
let event_signature = topics.get(0).ok_or(ErrorKind::InvalidData)?;
if event_signature != &self.signature() {
return Err(ErrorKind::InvalidData.into());
}
1
};
let topic_types = topic_params.iter()
.map(|p| self.convert_topic_param_type(&p.kind))
.collect::<Vec<ParamType>>();
let flat_topics = topics.into_iter()
.skip(to_skip)
.flat_map(|t| t.as_ref().to_vec())
.collect::<Vec<u8>>();
let topic_tokens = decode(&topic_types, &flat_topics)?;
if topic_tokens.len() != topics_len - to_skip {
return Err(ErrorKind::InvalidData.into());
}
let topics_named_tokens = topic_params.into_iter()
.map(|p| p.name)
.zip(topic_tokens.into_iter());
let data_types = data_params.iter()
.map(|p| p.kind.clone())
.collect::<Vec<ParamType>>();
let data_tokens = decode(&data_types, &data)?;
let data_named_tokens = data_params.into_iter()
.map(|p| p.name)
.zip(data_tokens.into_iter());
let named_tokens = topics_named_tokens
.chain(data_named_tokens)
.collect::<HashMap<String, Token>>();
let decoded_params = self.params_names()
.into_iter()
.map(|name| LogParam {
name: name.clone(),
value: named_tokens[&name].clone()
})
.collect();
let result = Log {
params: decoded_params,
};
Ok(result)
}
}
#[cfg(test)]
mod tests {
use hex::FromHex;
use token::Token;
use signature::long_signature;
use log::{RawLog, Log};
use {EventParam, ParamType, Event, LogParam};
#[test]
fn test_decoding_event() {
let event = Event {
name: "foo".to_owned(),
inputs: vec![EventParam {
name: "a".to_owned(),
kind: ParamType::Int(256),
indexed: false,
}, EventParam {
name: "b".to_owned(),
kind: ParamType::Int(256),
indexed: true,
}, EventParam {
name: "c".to_owned(),
kind: ParamType::Address,
indexed: false,
}, EventParam {
name: "d".to_owned(),
kind: ParamType::Address,
indexed: true,
}, EventParam {
name: "e".to_owned(),
kind: ParamType::String,
indexed: true,
}, EventParam {
name: "f".to_owned(),
kind: ParamType::Array(Box::new(ParamType::Int(256))),
indexed: true
}, EventParam {
name: "g".to_owned(),
kind: ParamType::FixedArray(Box::new(ParamType::Address), 5),
indexed: true,
}],
anonymous: false,
};
let log = RawLog {
topics: vec![
long_signature("foo", &[
ParamType::Int(256),
ParamType::Int(256),
ParamType::Address,
ParamType::Address,
ParamType::String,
ParamType::Array(Box::new(ParamType::Int(256))),
ParamType::FixedArray(Box::new(ParamType::Address), 5),
]),
"0000000000000000000000000000000000000000000000000000000000000002".parse().unwrap(),
"0000000000000000000000001111111111111111111111111111111111111111".parse().unwrap(),
"00000000000000000aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa".parse().unwrap(),
"00000000000000000bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb".parse().unwrap(),
"00000000000000000ccccccccccccccccccccccccccccccccccccccccccccccc".parse().unwrap(),
],
data:
("".to_owned() +
"0000000000000000000000000000000000000000000000000000000000000003" +
"0000000000000000000000002222222222222222222222222222222222222222").from_hex().unwrap()
};
let result = event.parse_log(log).unwrap();
assert_eq!(result, Log { params: vec![
("a".to_owned(), Token::Int("0000000000000000000000000000000000000000000000000000000000000003".into())),
("b".to_owned(), Token::Int("0000000000000000000000000000000000000000000000000000000000000002".into())),
("c".to_owned(), Token::Address("2222222222222222222222222222222222222222".parse().unwrap())),
("d".to_owned(), Token::Address("1111111111111111111111111111111111111111".parse().unwrap())),
("e".to_owned(), Token::FixedBytes("00000000000000000aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa".from_hex().unwrap())),
("f".to_owned(), Token::FixedBytes("00000000000000000bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb".from_hex().unwrap())),
("g".to_owned(), Token::FixedBytes("00000000000000000ccccccccccccccccccccccccccccccccccccccccccccccc".from_hex().unwrap())),
].into_iter().map(|(name, value)| LogParam { name, value }).collect::<Vec<_>>()});
}
}