precompile: Add support for hex source address

pallets/liquidity-pools-gateway/axelar-gateway-precompile/Cargo.toml

@@ -6,6 +6,7 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+hex = { version = "0.4.3", default-features = false }
 codec = { package = "parity-scale-codec", version = "3.0.0", features = ["derive"], default-features = false }
 frame-support = { git = "https://github.com/paritytech/substrate", default-features = false, branch = "polkadot-v0.9.38" }
 frame-system = { git = "https://github.com/paritytech/substrate", default-features = false, branch = "polkadot-v0.9.38" }

pallets/liquidity-pools-gateway/axelar-gateway-precompile/src/lib.rs

@@ -26,7 +26,8 @@ use sp_std::vec::Vec;
 pub use crate::weights::WeightInfo;
 
 pub const MAX_SOURCE_CHAIN_BYTES: u32 = 128;
-pub const MAX_SOURCE_ADDRESS_BYTES: u32 = 32;
+// Ensure we allow enough to support a hex encoded address with the `0x` prefix.
+pub const MAX_SOURCE_ADDRESS_BYTES: u32 = 42;
 pub const MAX_TOKEN_SYMBOL_BYTES: u32 = 32;
 pub const MAX_PAYLOAD_BYTES: u32 = 1024;
 pub const PREFIX_CONTRACT_CALL_APPROVED: [u8; 32] = keccak256!("contract-call-approved");
@@ -273,8 +274,13 @@ where
 			exit_status: ExitError::Other("converter for source not found".into()),
 		})?;
 
+		let source_address_bytes =
+			get_source_address_bytes(source_address).ok_or(PrecompileFailure::Error {
+				exit_status: ExitError::Other("invalid source address".into()),
+			})?;
+
 		let domain_address = domain_converter
-			.try_convert(source_address.as_bytes())
+			.try_convert(source_address_bytes.as_slice())
 			.ok_or(PrecompileFailure::Error {
 				exit_status: ExitError::Other("account bytes mismatch for domain".into()),
 			})?;
@@ -320,3 +326,55 @@ where
 		Ok(())
 	}
 }
+
+const EXPECTED_SOURCE_ADDRESS_SIZE: usize = 20;
+const HEX_PREFIX: &str = "0x";
+
+pub(crate) fn get_source_address_bytes(
+	source_address: String<MAX_SOURCE_ADDRESS_BYTES>,
+) -> Option<Vec<u8>> {
+	if source_address.as_bytes().len() == EXPECTED_SOURCE_ADDRESS_SIZE {
+		return Some(source_address.as_bytes().to_vec());
+	}
+
+	let str = source_address.as_str().ok()?;
+
+	// Attempt to hex decode source address.
+	return match hex::decode(str.clone()) {
+		Ok(res) => Some(res),
+		Err(_) => {
+			// Strip 0x prefix.
+			let res = str.strip_prefix(HEX_PREFIX)?;
+
+			hex::decode(res).ok()
+		}
+	};
+}
+
+#[cfg(test)]
+mod tests {
+	use sp_core::H160;
+
+	use super::*;
+
+	#[test]
+	fn get_source_address_bytes_works() {
+		let hash = H160::from_low_u64_be(1);
+
+		let str = String::<MAX_SOURCE_ADDRESS_BYTES>::from(hash.as_fixed_bytes().to_vec());
+
+		get_source_address_bytes(str).expect("address bytes from H160 works");
+
+		let str = String::<MAX_SOURCE_ADDRESS_BYTES>::from(
+			"d47ed02acbbb66ee8a3fe0275bd98add0aa607c3".to_string(),
+		);
+
+		get_source_address_bytes(str).expect("address bytes from un-prefixed hex works");
+
+		let str = String::<MAX_SOURCE_ADDRESS_BYTES>::from(
+			"0xd47ed02acbbb66ee8a3fe0275bd98add0aa607c3".to_string(),
+		);
+
+		get_source_address_bytes(str).expect("address bytes from prefixed hex works");
+	}
+}