Ledger/transaction_logic: extract verifiable module to separate file

Extract the verifiable module from transaction_logic/mod.rs into its own
file. This module contains the verifiable UserCommand enum (with serde
traits) and signature verification functions.

Changes:
- Extract verifiable module to transaction_logic/verifiable.rs
- Use explicit imports instead of 'use super::*'
- Update mod.rs to reference the new module file

Author: dannywillems

ledger/src/scan_state/transaction_logic/mod.rs

@@ -610,56 +610,7 @@ pub mod signed_command;
 pub mod zkapp_command;
 pub mod zkapp_statement;
 
-pub mod verifiable {
-    use std::ops::Neg;
-
-    use ark_ff::{BigInteger, PrimeField};
-
-    use super::*;
-
-    #[derive(Clone, Debug, serde::Serialize, serde::Deserialize)]
-    pub enum UserCommand {
-        SignedCommand(Box<signed_command::SignedCommand>),
-        ZkAppCommand(Box<zkapp_command::verifiable::ZkAppCommand>),
-    }
-
-    pub fn compressed_to_pubkey(pubkey: &CompressedPubKey) -> mina_signer::PubKey {
-        // Taken from https://github.com/o1-labs/proof-systems/blob/e3fc04ce87f8695288de167115dea80050ab33f4/signer/src/pubkey.rs#L95-L106
-        let mut pt =
-            mina_signer::CurvePoint::get_point_from_x_unchecked(pubkey.x, pubkey.is_odd).unwrap();
-
-        if pt.y.into_bigint().is_even() == pubkey.is_odd {
-            pt.y = pt.y.neg();
-        }
-
-        assert!(pt.is_on_curve());
-
-        // Safe now because we checked point pt is on curve
-        mina_signer::PubKey::from_point_unsafe(pt)
-    }
-
-    /// <https://github.com/MinaProtocol/mina/blob/05c2f73d0f6e4f1341286843814ce02dcb3919e0/src/lib/mina_base/signed_command.ml#L436>
-    pub fn check_only_for_signature(
-        cmd: Box<signed_command::SignedCommand>,
-    ) -> Result<valid::UserCommand, Box<signed_command::SignedCommand>> {
-        // <https://github.com/MinaProtocol/mina/blob/05c2f73d0f6e4f1341286843814ce02dcb3919e0/src/lib/mina_base/signed_command.ml#L396>
-
-        let signed_command::SignedCommand {
-            payload,
-            signer: pubkey,
-            signature,
-        } = &*cmd;
-
-        let payload = TransactionUnionPayload::of_user_command_payload(payload);
-        let pubkey = compressed_to_pubkey(pubkey);
-
-        if crate::verifier::common::legacy_verify_signature(signature, &pubkey, &payload) {
-            Ok(valid::UserCommand::SignedCommand(cmd))
-        } else {
-            Err(cmd)
-        }
-    }
-}
+pub mod verifiable;
 
 #[derive(Clone, Debug, PartialEq)]
 pub enum UserCommand {

ledger/src/scan_state/transaction_logic/verifiable.rs

@@ -0,0 +1,52 @@
+use std::ops::Neg;
+
+use ark_ff::{BigInteger, PrimeField};
+use mina_signer::CompressedPubKey;
+
+use super::{
+    signed_command, transaction_union_payload::TransactionUnionPayload, valid,
+    zkapp_command,
+};
+
+#[derive(Clone, Debug, serde::Serialize, serde::Deserialize)]
+pub enum UserCommand {
+    SignedCommand(Box<signed_command::SignedCommand>),
+    ZkAppCommand(Box<zkapp_command::verifiable::ZkAppCommand>),
+}
+
+pub fn compressed_to_pubkey(pubkey: &CompressedPubKey) -> mina_signer::PubKey {
+    // Taken from https://github.com/o1-labs/proof-systems/blob/e3fc04ce87f8695288de167115dea80050ab33f4/signer/src/pubkey.rs#L95-L106
+    let mut pt =
+        mina_signer::CurvePoint::get_point_from_x_unchecked(pubkey.x, pubkey.is_odd).unwrap();
+
+    if pt.y.into_bigint().is_even() == pubkey.is_odd {
+        pt.y = pt.y.neg();
+    }
+
+    assert!(pt.is_on_curve());
+
+    // Safe now because we checked point pt is on curve
+    mina_signer::PubKey::from_point_unsafe(pt)
+}
+
+/// <https://github.com/MinaProtocol/mina/blob/05c2f73d0f6e4f1341286843814ce02dcb3919e0/src/lib/mina_base/signed_command.ml#L436>
+pub fn check_only_for_signature(
+    cmd: Box<signed_command::SignedCommand>,
+) -> Result<valid::UserCommand, Box<signed_command::SignedCommand>> {
+    // <https://github.com/MinaProtocol/mina/blob/05c2f73d0f6e4f1341286843814ce02dcb3919e0/src/lib/mina_base/signed_command.ml#L396>
+
+    let signed_command::SignedCommand {
+        payload,
+        signer: pubkey,
+        signature,
+    } = &*cmd;
+
+    let payload = TransactionUnionPayload::of_user_command_payload(payload);
+    let pubkey = compressed_to_pubkey(pubkey);
+
+    if crate::verifier::common::legacy_verify_signature(signature, &pubkey, &payload) {
+        Ok(valid::UserCommand::SignedCommand(cmd))
+    } else {
+        Err(cmd)
+    }
+}