feat(utils): add MultiSigner helper

core/src/utils/mod.rs

@@ -10,6 +10,7 @@ pub mod bits;
 mod era;
 mod multi_address;
 mod multi_signature;
+mod multi_signer;
 mod static_type;
 mod unchecked_extrinsic;
 mod wrapper_opaque;
@@ -26,6 +27,7 @@ pub use account_id20::AccountId20;
 pub use era::Era;
 pub use multi_address::MultiAddress;
 pub use multi_signature::MultiSignature;
+pub use multi_signer::MultiSigner;
 pub use primitive_types::{H160, H256, H512};
 pub use static_type::Static;
 pub use unchecked_extrinsic::UncheckedExtrinsic;

core/src/utils/multi_signer.rs

@@ -0,0 +1,58 @@
+// Copyright 2019-2024 Parity Technologies (UK) Ltd.
+// This file is dual-licensed as Apache-2.0 or GPL-3.0.
+// see LICENSE for license details.
+
+//! The "default" Substrate/Polkadot Signer type. This is used in signature verification and related bits.
+//! This doesn't contain much functionality itself, but is easy to convert to/from an `sp_runtime::MultiSigner`
+//! for instance, to gain functionality without forcing a dependency on Substrate crates here.
+
+use codec::{Decode, Encode};
+
+/// Signer container that can store known signer types. This is a simplified version of
+/// `sp_runtime::MultiSigner`. To obtain more functionality, convert this into that type.
+#[derive(Clone, Eq, PartialEq, Ord, PartialOrd, Encode, Decode, Debug, scale_info::TypeInfo)]
+pub enum MultiSigner {
+    /// An Ed25519 public key.
+    Ed25519([u8; 32]),
+    /// An Sr25519 public key.
+    Sr25519([u8; 32]),
+    /// An ECDSA/SECP256k1 public key.
+    Ecdsa([u8; 33]),
+}
+
+// Improve compat with the substrate version if we're using those crates:
+#[cfg(feature = "substrate-compat")]
+mod substrate_impls {
+    use super::*;
+
+    impl From<sp_runtime::MultiSigner> for MultiSigner {
+        fn from(value: sp_runtime::MultiSigner) -> Self {
+            match value {
+                sp_runtime::MultiSigner::Ed25519(s) => Self::Ed25519(s.0),
+                sp_runtime::MultiSigner::Sr25519(s) => Self::Sr25519(s.0),
+                sp_runtime::MultiSigner::Ecdsa(s) => Self::Ecdsa(s.0),
+            }
+        }
+    }
+
+    impl From<sp_core::ed25519::Public> for MultiSigner {
+        fn from(value: sp_core::ed25519::Public) -> Self {
+            let signer: sp_runtime::MultiSigner = value.into();
+            signer.into()
+        }
+    }
+
+    impl From<sp_core::sr25519::Public> for MultiSigner {
+        fn from(value: sp_core::sr25519::Public) -> Self {
+            let signer: sp_runtime::MultiSigner = value.into();
+            signer.into()
+        }
+    }
+
+    impl From<sp_core::ecdsa::Public> for MultiSigner {
+        fn from(value: sp_core::ecdsa::Public) -> Self {
+            let signer: sp_runtime::MultiSigner = value.into();
+            signer.into()
+        }
+    }
+}

subxt/src/utils/mod.rs

@@ -10,8 +10,8 @@ use url::Url;
 
 pub use subxt_core::utils::{
     bits, strip_compact_prefix, to_hex, AccountId32, Encoded, Era, KeyedVec, MultiAddress,
-    MultiSignature, PhantomDataSendSync, Static, UncheckedExtrinsic, WrapperKeepOpaque, Yes, H160,
-    H256, H512,
+    MultiSignature, MultiSigner, PhantomDataSendSync, Static, UncheckedExtrinsic, WrapperKeepOpaque,
+    Yes, H160, H256, H512,
 };
 
 cfg_jsonrpsee! {