Misc Fixes (#97)

* fix: use generic instead of impl Trait

* fix: do not skip first 4 bytes when decoding outputs

ethers-contract/src/base.rs

@@ -21,6 +21,9 @@ pub enum AbiError {
     /// Thrown when detokenizing an argument
     #[error(transparent)]
     DetokenizationError(#[from] InvalidOutputType),
+
+    #[error("missing or wrong function selector")]
+    WrongSelector,
 }
 
 /// A reduced form of `Contract` which just takes the `abi` and produces
@@ -33,7 +36,7 @@ pub struct BaseContract {
     /// functions in the contract ABI. This is used to avoid allocation when
     /// searching for matching functions by signature.
     // Adapted from: https://github.com/gnosis/ethcontract-rs/blob/master/src/contract.rs
-    pub(crate) methods: HashMap<Selector, (String, usize)>,
+    pub methods: HashMap<Selector, (String, usize)>,
 }
 
 impl From<Abi> for BaseContract {
@@ -68,10 +71,10 @@ impl BaseContract {
     ///
     /// If the function exists multiple times and you want to use one of the overloaded
     /// versions, consider using `decode_with_selector`
-    pub fn decode<D: Detokenize>(
+    pub fn decode<D: Detokenize, T: AsRef<[u8]>>(
         &self,
         name: &str,
-        bytes: impl AsRef<[u8]>,
+        bytes: T,
     ) -> Result<D, AbiError> {
         let function = self.abi.function(name)?;
         decode_fn(function, bytes, true)
@@ -90,10 +93,10 @@ impl BaseContract {
     }
 
     /// Decodes the provided ABI encoded bytes with the selected function selector
-    pub fn decode_with_selector<D: Detokenize>(
+    pub fn decode_with_selector<D: Detokenize, T: AsRef<[u8]>>(
         &self,
         signature: Selector,
-        bytes: impl AsRef<[u8]>,
+        bytes: T,
     ) -> Result<D, AbiError> {
         let function = self.get_from_signature(signature)?;
         decode_fn(function, bytes, true)
@@ -152,20 +155,19 @@ pub(crate) fn encode_fn<T: Tokenize>(function: &Function, args: T) -> Result<Byt
 }
 
 // Helper for decoding bytes from a specific function
-pub(crate) fn decode_fn<D: Detokenize>(
+pub fn decode_fn<D: Detokenize, T: AsRef<[u8]>>(
     function: &Function,
-    bytes: impl AsRef<[u8]>,
+    bytes: T,
     is_input: bool,
 ) -> Result<D, AbiError> {
-    let mut bytes = bytes.as_ref();
-    if bytes.starts_with(&function.selector()) {
-        bytes = &bytes[4..];
-    }
-
+    let bytes = bytes.as_ref();
     let tokens = if is_input {
-        function.decode_input(bytes.as_ref())?
+        if bytes.len() < 4 || bytes[..4] != function.selector() {
+            return Err(AbiError::WrongSelector);
+        }
+        function.decode_input(&bytes[4..])?
     } else {
-        function.decode_output(bytes.as_ref())?
+        function.decode_output(bytes)?
     };
 
     Ok(D::from_tokens(tokens)?)

ethers-contract/src/lib.rs

@@ -17,7 +17,7 @@ mod contract;
 pub use contract::Contract;
 
 mod base;
-pub use base::BaseContract;
+pub use base::{decode_fn, BaseContract};
 
 mod call;
 pub use call::ContractError;

ethers-core/src/types/bytes.rs

@@ -3,7 +3,7 @@ use serde::de::{Error, Unexpected};
 use serde::{Deserialize, Deserializer, Serialize, Serializer};
 
 /// Wrapper type around Vec<u8> to deserialize/serialize "0x" prefixed ethereum hex strings
-#[derive(Clone, Debug, Default, PartialEq, Eq, Hash, Serialize, Deserialize)]
+#[derive(Clone, Debug, Default, PartialEq, Eq, Hash, Serialize, Deserialize, Ord, PartialOrd)]
 pub struct Bytes(
     #[serde(
         serialize_with = "serialize_bytes",

ethers-providers/src/lib.rs

@@ -380,7 +380,7 @@ pub trait Middleware: Sync + Send + Debug {
         req: TransactionRequest,
         trace_type: Vec<TraceType>,
         block: Option<BlockNumber>,
-    ) -> Result<BlockTrace, ProviderError> {
+    ) -> Result<BlockTrace, Self::Error> {
         self.inner()
             .trace_call(req, trace_type, block)
             .await
@@ -392,7 +392,7 @@ pub trait Middleware: Sync + Send + Debug {
         &self,
         data: Bytes,
         trace_type: Vec<TraceType>,
-    ) -> Result<BlockTrace, ProviderError> {
+    ) -> Result<BlockTrace, Self::Error> {
         self.inner()
             .trace_raw_transaction(data, trace_type)
             .await
@@ -404,7 +404,7 @@ pub trait Middleware: Sync + Send + Debug {
         &self,
         hash: H256,
         trace_type: Vec<TraceType>,
-    ) -> Result<BlockTrace, ProviderError> {
+    ) -> Result<BlockTrace, Self::Error> {
         self.inner()
             .trace_replay_transaction(hash, trace_type)
             .await
@@ -416,7 +416,7 @@ pub trait Middleware: Sync + Send + Debug {
         &self,
         block: BlockNumber,
         trace_type: Vec<TraceType>,
-    ) -> Result<Vec<BlockTrace>, ProviderError> {
+    ) -> Result<Vec<BlockTrace>, Self::Error> {
         self.inner()
             .trace_replay_block_transactions(block, trace_type)
             .await
@@ -424,12 +424,12 @@ pub trait Middleware: Sync + Send + Debug {
     }
 
     /// Returns traces created at given block
-    async fn trace_block(&self, block: BlockNumber) -> Result<Vec<Trace>, ProviderError> {
+    async fn trace_block(&self, block: BlockNumber) -> Result<Vec<Trace>, Self::Error> {
         self.inner().trace_block(block).await.map_err(FromErr::from)
     }
 
     /// Return traces matching the given filter
-    async fn trace_filter(&self, filter: TraceFilter) -> Result<Vec<Trace>, ProviderError> {
+    async fn trace_filter(&self, filter: TraceFilter) -> Result<Vec<Trace>, Self::Error> {
         self.inner()
             .trace_filter(filter)
             .await
@@ -441,7 +441,7 @@ pub trait Middleware: Sync + Send + Debug {
         &self,
         hash: H256,
         index: Vec<T>,
-    ) -> Result<Trace, ProviderError> {
+    ) -> Result<Trace, Self::Error> {
         self.inner()
             .trace_get(hash, index)
             .await
@@ -449,7 +449,7 @@ pub trait Middleware: Sync + Send + Debug {
     }
 
     /// Returns all traces of a given transaction
-    async fn trace_transaction(&self, hash: H256) -> Result<Vec<Trace>, ProviderError> {
+    async fn trace_transaction(&self, hash: H256) -> Result<Vec<Trace>, Self::Error> {
         self.inner()
             .trace_transaction(hash)
             .await