Add Scalar and SharedSecret type mappings for new secp256k1 types

Author: TheBlueMatt

c-bindings-gen/src/types.rs

@@ -936,6 +936,10 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
 			"bitcoin::secp256k1::ecdsa::RecoverableSignature" => Some("crate::c_types::RecoverableSignature"),
 			"bitcoin::secp256k1::SecretKey" if is_ref  => Some("*const [u8; 32]"),
 			"bitcoin::secp256k1::SecretKey" if !is_ref => Some("crate::c_types::SecretKey"),
+			"bitcoin::secp256k1::Scalar" if is_ref  => Some("*const crate::c_types::BigEndianScalar"),
+			"bitcoin::secp256k1::Scalar" if !is_ref => Some("crate::c_types::BigEndianScalar"),
+			"bitcoin::secp256k1::ecdh::SharedSecret" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
+
 			"bitcoin::blockdata::script::Script" if is_ref => Some("crate::c_types::u8slice"),
 			"bitcoin::blockdata::script::Script" if !is_ref => Some("crate::c_types::derived::CVec_u8Z"),
 			"bitcoin::blockdata::transaction::OutPoint" => Some("crate::lightning::chain::transaction::OutPoint"),
@@ -1021,6 +1025,9 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
 			"bitcoin::secp256k1::ecdsa::RecoverableSignature" => Some(""),
 			"bitcoin::secp256k1::SecretKey" if is_ref => Some("&::bitcoin::secp256k1::SecretKey::from_slice(&unsafe { *"),
 			"bitcoin::secp256k1::SecretKey" if !is_ref => Some(""),
+			"bitcoin::secp256k1::Scalar" if !is_ref => Some(""),
+			"bitcoin::secp256k1::ecdh::SharedSecret" if !is_ref => Some("::bitcoin::secp256k1::ecdh::SharedSecret::from_bytes("),
+
 			"bitcoin::blockdata::script::Script" if is_ref => Some("&::bitcoin::blockdata::script::Script::from(Vec::from("),
 			"bitcoin::blockdata::script::Script" if !is_ref => Some("::bitcoin::blockdata::script::Script::from("),
 			"bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" if is_ref => Some("&"),
@@ -1104,6 +1111,9 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
 			"bitcoin::secp256k1::ecdsa::RecoverableSignature" => Some(".into_rust()"),
 			"bitcoin::secp256k1::SecretKey" if !is_ref => Some(".into_rust()"),
 			"bitcoin::secp256k1::SecretKey" if is_ref => Some("}[..]).unwrap()"),
+			"bitcoin::secp256k1::Scalar" if !is_ref => Some(".into_rust()"),
+			"bitcoin::secp256k1::ecdh::SharedSecret" if !is_ref => Some(".data)"),
+
 			"bitcoin::blockdata::script::Script" if is_ref => Some(".to_slice()))"),
 			"bitcoin::blockdata::script::Script" if !is_ref => Some(".into_rust())"),
 			"bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" => Some(".into_bitcoin()"),
@@ -1196,6 +1206,9 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
 			"bitcoin::secp256k1::ecdsa::RecoverableSignature" => Some("crate::c_types::RecoverableSignature::from_rust(&"),
 			"bitcoin::secp256k1::SecretKey" if is_ref => Some(""),
 			"bitcoin::secp256k1::SecretKey" if !is_ref => Some("crate::c_types::SecretKey::from_rust("),
+			"bitcoin::secp256k1::Scalar" if !is_ref => Some("crate::c_types::BigEndianScalar::from_rust("),
+			"bitcoin::secp256k1::ecdh::SharedSecret" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
+
 			"bitcoin::blockdata::script::Script" if is_ref => Some("crate::c_types::u8slice::from_slice(&"),
 			"bitcoin::blockdata::script::Script" if !is_ref => Some(""),
 			"bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" if is_ref => Some("crate::c_types::Transaction::from_bitcoin("),
@@ -1273,6 +1286,9 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
 			"bitcoin::secp256k1::ecdsa::RecoverableSignature" => Some(")"),
 			"bitcoin::secp256k1::SecretKey" if !is_ref => Some(")"),
 			"bitcoin::secp256k1::SecretKey" if is_ref => Some(".as_ref()"),
+			"bitcoin::secp256k1::Scalar" if !is_ref => Some(")"),
+			"bitcoin::secp256k1::ecdh::SharedSecret" if !is_ref => Some(".secret_bytes() }"),
+
 			"bitcoin::blockdata::script::Script" if is_ref => Some("[..])"),
 			"bitcoin::blockdata::script::Script" if !is_ref => Some(".into_bytes().into()"),
 			"bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" => Some(")"),

lightning-c-bindings/src/c_types/mod.rs

@@ -11,6 +11,7 @@ use bitcoin::secp256k1::ecdsa::Signature as SecpSignature;
 use bitcoin::secp256k1::Error as SecpError;
 use bitcoin::secp256k1::ecdsa::RecoveryId;
 use bitcoin::secp256k1::ecdsa::RecoverableSignature as SecpRecoverableSignature;
+use bitcoin::secp256k1::Scalar as SecpScalar;
 use bitcoin::bech32;
 use bitcoin::util::address;
 
@@ -149,6 +150,22 @@ impl RecoverableSignature {
 	}
 }
 
+#[repr(C)]
+#[derive(Clone)]
+/// Represents a scalar value between zero and the secp256k1 curve order, in big endian.
+pub struct BigEndianScalar {
+	/// The bytes of the scalar value.
+	pub big_endian_bytes: [u8; 32],
+}
+impl BigEndianScalar {
+	pub(crate) fn from_rust(scalar: &SecpScalar) -> Self {
+		Self { big_endian_bytes: scalar.to_be_bytes() }
+	}
+	pub(crate) fn into_rust(&self) -> SecpScalar {
+		SecpScalar::from_be_bytes(self.big_endian_bytes).expect("Scalar greater than the curve order")
+	}
+}
+
 #[repr(C)]
 #[derive(Copy, Clone)]
 /// Represents an error returned from libsecp256k1 during validation of some secp256k1 data