refactor: Factor out note scripts

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## 0.6.0 (TBD)
 
+- Made note scripts public (#880).
 - Implemented serialization for `TransactionWitness`, `ChainMmr`, `TransactionInputs` and `TransactionArgs` (#888).
 - [BREAKING] Renamed the `TransactionProver` struct to `LocalTransactionProver` and added the `TransactionProver` trait (#865).
 - Implemented `Display`, `TryFrom<&str>` and `FromStr` for `AccountStorageMode` (#861).

miden-lib/src/notes/mod.rs

@@ -6,13 +6,13 @@ use miden_objects::{
     crypto::rand::FeltRng,
     notes::{
         Note, NoteAssets, NoteDetails, NoteExecutionHint, NoteExecutionMode, NoteInputs,
-        NoteMetadata, NoteRecipient, NoteScript, NoteTag, NoteType,
+        NoteMetadata, NoteRecipient, NoteTag, NoteType,
     },
-    utils::Deserializable,
-    vm::Program,
     Felt, NoteError, Word,
 };
+use utils::build_swap_tag;
 
+pub mod scripts;
 pub mod utils;
 
 // STANDARDIZED SCRIPTS
@@ -36,10 +36,7 @@ pub fn create_p2id_note<R: FeltRng>(
     aux: Felt,
     rng: &mut R,
 ) -> Result<Note, NoteError> {
-    let bytes = include_bytes!(concat!(env!("OUT_DIR"), "/assets/note_scripts/P2ID.masb"));
-    let program =
-        Program::read_from_bytes(bytes).map_err(NoteError::NoteScriptDeserializationError)?;
-    let note_script = NoteScript::new(program);
+    let note_script = scripts::p2id();
 
     let inputs = NoteInputs::new(vec![target.into()])?;
     let tag = NoteTag::from_account_id(target, NoteExecutionMode::Local)?;
@@ -72,10 +69,7 @@ pub fn create_p2idr_note<R: FeltRng>(
     recall_height: u32,
     rng: &mut R,
 ) -> Result<Note, NoteError> {
-    let bytes = include_bytes!(concat!(env!("OUT_DIR"), "/assets/note_scripts/P2IDR.masb"));
-    let program =
-        Program::read_from_bytes(bytes).map_err(NoteError::NoteScriptDeserializationError)?;
-    let note_script = NoteScript::new(program);
+    let note_script = scripts::p2idr();
 
     let inputs = NoteInputs::new(vec![target.into(), recall_height.into()])?;
     let tag = NoteTag::from_account_id(target, NoteExecutionMode::Local)?;
@@ -104,10 +98,7 @@ pub fn create_swap_note<R: FeltRng>(
     aux: Felt,
     rng: &mut R,
 ) -> Result<(Note, NoteDetails), NoteError> {
-    let bytes = include_bytes!(concat!(env!("OUT_DIR"), "/assets/note_scripts/SWAP.masb"));
-    let program =
-        Program::read_from_bytes(bytes).map_err(NoteError::NoteScriptDeserializationError)?;
-    let note_script = NoteScript::new(program);
+    let note_script = scripts::swap();
 
     let payback_serial_num = rng.draw_word();
     let payback_recipient = utils::build_p2id_recipient(sender, payback_serial_num)?;
@@ -145,40 +136,3 @@ pub fn create_swap_note<R: FeltRng>(
 
     Ok((note, payback_note))
 }
-
-// HELPER FUNCTIONS
-// ================================================================================================
-
-/// Returns a note tag for a swap note with the specified parameters.
-///
-/// Use case ID for the returned tag is set to 0.
-///
-/// Tag payload is constructed by taking asset tags (8 bits of faucet ID) and concatenating them
-/// together as offered_asset_tag + requested_asset tag.
-///
-/// Network execution hint for the returned tag is set to `Local`.
-pub fn build_swap_tag(
-    note_type: NoteType,
-    offered_asset: &Asset,
-    requested_asset: &Asset,
-) -> Result<NoteTag, NoteError> {
-    const SWAP_USE_CASE_ID: u16 = 0;
-
-    // get bits 4..12 from faucet IDs of both assets, these bits will form the tag payload; the
-    // reason we skip the 4 most significant bits is that these encode metadata of underlying
-    // faucets and are likely to be the same for many different faucets.
-
-    let offered_asset_id: u64 = offered_asset.faucet_id().into();
-    let offered_asset_tag = (offered_asset_id >> 52) as u8;
-
-    let requested_asset_id: u64 = requested_asset.faucet_id().into();
-    let requested_asset_tag = (requested_asset_id >> 52) as u8;
-
-    let payload = ((offered_asset_tag as u16) << 8) | (requested_asset_tag as u16);
-
-    let execution = NoteExecutionMode::Local;
-    match note_type {
-        NoteType::Public => NoteTag::for_public_use_case(SWAP_USE_CASE_ID, payload, execution),
-        _ => NoteTag::for_local_use_case(SWAP_USE_CASE_ID, payload),
-    }
-}

miden-lib/src/notes/scripts.rs

@@ -0,0 +1,25 @@
+use miden_objects::{notes::NoteScript, utils::Deserializable, vm::Program};
+
+/// Returns a P2ID (Pay-to-ID) note script.
+pub fn p2id() -> NoteScript {
+    let bytes = include_bytes!(concat!(env!("OUT_DIR"), "/assets/note_scripts/P2ID.masb"));
+    let program = Program::read_from_bytes(bytes).expect("Shipped P2ID script is well-formed");
+
+    NoteScript::new(program)
+}
+
+/// Returns a P2IDR (Pay-to-ID with recall) note script.
+pub fn p2idr() -> NoteScript {
+    let bytes = include_bytes!(concat!(env!("OUT_DIR"), "/assets/note_scripts/P2IDR.masb"));
+    let program = Program::read_from_bytes(bytes).expect("Shipped P2IDR script is well-formed");
+
+    NoteScript::new(program)
+}
+
+/// Returns a SWAP (Pay-to-ID with recall) note script.
+pub fn swap() -> NoteScript {
+    let bytes = include_bytes!(concat!(env!("OUT_DIR"), "/assets/note_scripts/SWAP.masb"));
+    let program = Program::read_from_bytes(bytes).expect("Shipped SWAP script is well-formed");
+
+    NoteScript::new(program)
+}

miden-lib/src/notes/utils.rs

@@ -1,6 +1,7 @@
 use miden_objects::{
     accounts::AccountId,
-    notes::{NoteInputs, NoteRecipient, NoteScript},
+    assets::Asset,
+    notes::{NoteExecutionMode, NoteInputs, NoteRecipient, NoteScript, NoteTag, NoteType},
     utils::Deserializable,
     vm::Program,
     NoteError, Word,
@@ -22,3 +23,37 @@ pub fn build_p2id_recipient(
 
     Ok(NoteRecipient::new(serial_num, note_script, note_inputs))
 }
+
+/// Returns a note tag for a swap note with the specified parameters.
+///
+/// Use case ID for the returned tag is set to 0.
+///
+/// Tag payload is constructed by taking asset tags (8 bits of faucet ID) and concatenating them
+/// together as offered_asset_tag + requested_asset tag.
+///
+/// Network execution hint for the returned tag is set to `Local`.
+pub fn build_swap_tag(
+    note_type: NoteType,
+    offered_asset: &Asset,
+    requested_asset: &Asset,
+) -> Result<NoteTag, NoteError> {
+    const SWAP_USE_CASE_ID: u16 = 0;
+
+    // get bits 4..12 from faucet IDs of both assets, these bits will form the tag payload; the
+    // reason we skip the 4 most significant bits is that these encode metadata of underlying
+    // faucets and are likely to be the same for many different faucets.
+
+    let offered_asset_id: u64 = offered_asset.faucet_id().into();
+    let offered_asset_tag = (offered_asset_id >> 52) as u8;
+
+    let requested_asset_id: u64 = requested_asset.faucet_id().into();
+    let requested_asset_tag = (requested_asset_id >> 52) as u8;
+
+    let payload = ((offered_asset_tag as u16) << 8) | (requested_asset_tag as u16);
+
+    let execution = NoteExecutionMode::Local;
+    match note_type {
+        NoteType::Public => NoteTag::for_public_use_case(SWAP_USE_CASE_ID, payload, execution),
+        _ => NoteTag::for_local_use_case(SWAP_USE_CASE_ID, payload),
+    }
+}