feat(codec): add hex encode and decode functions (#1059)

ethers-core/src/abi/codec.rs

@@ -9,12 +9,28 @@ use crate::{
 pub trait AbiEncode {
     /// ABI encode the type
     fn encode(self) -> Vec<u8>;
+
+    /// Returns the encoded value as hex string, _with_ a `0x` prefix
+    fn encode_hex(self) -> String
+    where
+        Self: Sized,
+    {
+        format!("0x{}", hex::encode(self.encode()))
+    }
 }
 
 /// Trait for ABI decoding
 pub trait AbiDecode: Sized {
     /// Decodes the ABI encoded data
     fn decode(bytes: impl AsRef<[u8]>) -> Result<Self, AbiError>;
+
+    /// Decode hex encoded ABI encoded data
+    ///
+    /// Expects a hex encoded string, with optional `0x` prefix
+    fn decode_hex(data: impl AsRef<str>) -> Result<Self, AbiError> {
+        let bytes: Bytes = data.as_ref().parse()?;
+        Self::decode(bytes)
+    }
 }
 
 macro_rules! impl_abi_codec {

ethers-core/src/abi/error.rs

@@ -24,6 +24,7 @@ pub(crate) use _format_err as format_err;
 macro_rules! _bail {
     ($($tt:tt)*) => { return Err($crate::abi::error::format_err!($($tt)*)) };
 }
+use crate::types::ParseBytesError;
 pub(crate) use _bail as bail;
 
 /// ABI codec related errors
@@ -39,4 +40,7 @@ pub enum AbiError {
 
     #[error("missing or wrong function selector")]
     WrongSelector,
+
+    #[error(transparent)]
+    ParseBytesError(#[from] ParseBytesError),
 }

ethers-core/src/types/mod.rs

@@ -25,7 +25,7 @@ mod i256;
 pub use i256::{Sign, I256};
 
 mod bytes;
-pub use self::bytes::Bytes;
+pub use self::bytes::{Bytes, ParseBytesError};
 
 mod block;
 pub use block::{Block, BlockId, BlockNumber};