Init

noir-projects/aztec-nr/aztec/src/encrypted_logs/incoming_body.nr

@@ -16,7 +16,7 @@ impl<M> EncryptedLogIncomingBody<M> {
     }
 
     pub fn from_event<T>(event: T, randomness: Field) -> Self where T: EventInterface<M> {
-        let mut plaintext = event.to_be_bytes(randomness);
+        let mut plaintext = event.private_to_be_bytes(randomness);
         EncryptedLogIncomingBody { plaintext }
     }
 
@@ -38,7 +38,7 @@ mod test {
     use dep::protocol_types::{
         address::AztecAddress, traits::Empty, constants::GENERATOR_INDEX__NOTE_NULLIFIER,
         grumpkin_private_key::GrumpkinPrivateKey, grumpkin_point::GrumpkinPoint, traits::Serialize,
-        abis::function_selector::FunctionSelector
+        abis::event_selector::EventSelector
     };
 
     use crate::{
@@ -155,15 +155,15 @@ mod test {
     global TEST_EVENT_BYTES_LEN = 32 * 3 + 64;
 
     impl EventInterface<TEST_EVENT_BYTES_LEN> for TestEvent {
-        fn _selector(self) -> FunctionSelector {
-            FunctionSelector::from_signature("TestEvent(Field,Field,Field)")
+        fn get_event_type_id(self) -> EventSelector {
+            EventSelector::from_signature("TestEvent(Field,Field,Field)")
         }
 
-        fn to_be_bytes(self, randomness: Field) -> [u8; TEST_EVENT_BYTES_LEN] {
+        fn private_to_be_bytes(self, randomness: Field) -> [u8; TEST_EVENT_BYTES_LEN] {
             let mut buffer: [u8; TEST_EVENT_BYTES_LEN] = [0; TEST_EVENT_BYTES_LEN];
 
             let randomness_bytes = randomness.to_be_bytes(32);
-            let event_type_id_bytes = self._selector().to_field().to_be_bytes(32);
+            let event_type_id_bytes = self.get_event_type_id().to_field().to_be_bytes(32);
 
             for i in 0..32 {
                 buffer[i] = randomness_bytes[i];

noir-projects/aztec-nr/aztec/src/event/event_interface.nr

@@ -1,9 +1,10 @@
 use crate::context::PrivateContext;
 use crate::note::note_header::NoteHeader;
-use dep::protocol_types::{grumpkin_point::GrumpkinPoint, abis::function_selector::FunctionSelector};
+use dep::protocol_types::{grumpkin_point::GrumpkinPoint, abis::event_selector::EventSelector};
 
-trait EventInterface<N> {
-    // Should be autogenerated by the #[aztec(event)] macro unless it is overridden by a custom implementation
-    fn _selector(self) -> FunctionSelector;
-    fn to_be_bytes(self, randomness: Field) -> [u8; N];
+trait EventInterface<M> {
+    fn private_to_be_bytes(self, randomness: Field) -> [u8; M];
+    // More than one generic breaks this
+    // fn to_be_bytes(self) -> [u8; M];
+    fn get_event_type_id(self) -> EventSelector;
 }

noir-projects/noir-contracts/contracts/crowdfunding_contract/src/main.nr

@@ -17,14 +17,8 @@ contract Crowdfunding {
 
     #[aztec(event)]
     struct WithdrawalProcessed {
-        who: AztecAddress,
-        amount: u64,
-    }
-
-    impl Serialize<2> for WithdrawalProcessed {
-        fn serialize(self: Self) -> [Field; 2] {
-            [self.who.to_field(), self.amount as Field]
-        }
+        who: Field,
+        amount: Field,
     }
 
     // docs:start:storage
@@ -103,7 +97,7 @@ contract Crowdfunding {
         Token::at(storage.donation_token.read_private()).transfer(operator_address, amount as Field).call(&mut context);
 
         // 3) Emit an unencrypted event so that anyone can audit how much the operator has withdrawn
-        let event = WithdrawalProcessed { amount, who: operator_address };
+        let event = WithdrawalProcessed { amount: amount as Field, who: operator_address.to_field() };
         context.emit_unencrypted_log(event.serialize());
     }
     // docs:end:operator-withdrawals

noir-projects/noir-contracts/contracts/test_log_contract/src/main.nr

@@ -14,56 +14,12 @@ contract TestLog {
         value1: Field,
     }
 
-    // This should be autogenerated by the macros
-    global EXAMPLE_EVENT_0_BYTES_LEN = 32 * 2 + 32 + 32;
-
-    impl EventInterface<EXAMPLE_EVENT_0_BYTES_LEN> for ExampleEvent0 {
-        fn _selector(self) -> FunctionSelector {
-            FunctionSelector::from_signature("TestEvent(Field,Field,Field)")
-        }
-
-        fn to_be_bytes(self, randomness: Field) -> [u8; EXAMPLE_EVENT_0_BYTES_LEN] {
-            let mut buffer: [u8; EXAMPLE_EVENT_0_BYTES_LEN] = [0; EXAMPLE_EVENT_0_BYTES_LEN];
-
-            let randomness_bytes = randomness.to_be_bytes(32);
-            let event_type_id_bytes = self._selector().to_field().to_be_bytes(32);
-
-            for i in 0..32 {
-                buffer[i] = randomness_bytes[i];
-                buffer[32 + i] = event_type_id_bytes[i];
-            }
-
-            let serialized_event = self.serialize();
-
-            for i in 0..serialized_event.len() {
-                let bytes = serialized_event[i].to_be_bytes(32);
-                for j in 0..32 {
-                    buffer[64 + i * 32 + j] = bytes[j];
-                }
-            }
-
-            buffer
-        }
-    }
-
     #[aztec(event)]
     struct ExampleEvent1 {
         value2: Field,
         value3: Field,
     }
 
-    impl Serialize<2> for ExampleEvent0 {
-        fn serialize(self) -> [Field; 2] {
-            [self.value0, self.value1]
-        }
-    }
-
-    impl Serialize<2> for ExampleEvent1 {
-        fn serialize(self) -> [Field; 2] {
-            [self.value2, self.value3]
-        }
-    }
-
     #[aztec(storage)]
     struct Storage {
         example_set: PrivateSet<ValueNote>,

noir-projects/noir-protocol-circuits/crates/types/src/abis.nr

@@ -2,6 +2,7 @@ mod append_only_tree_snapshot;
 
 mod contract_class_function_leaf_preimage;
 
+mod event_selector;
 mod function_selector;
 mod function_data;
 

noir-projects/noir-protocol-circuits/crates/types/src/abis/event_selector.nr

@@ -0,0 +1,70 @@
+use crate::utils::field::field_from_bytes;
+use dep::std::cmp::Eq;
+use crate::traits::{Serialize, Deserialize, FromField, ToField, Empty};
+
+global SELECTOR_SIZE = 4;
+
+struct EventSelector {
+    // 1st 4-bytes of abi-encoding of an event.
+    inner: u32,
+}
+
+impl Eq for EventSelector {
+    fn eq(self, other: EventSelector) -> bool {
+        other.inner == self.inner
+    }
+}
+
+impl Serialize<1> for EventSelector {
+    fn serialize(self: Self) -> [Field; 1] {
+        [self.inner as Field]
+    }
+}
+
+impl Deserialize<1> for EventSelector {
+    fn deserialize(fields: [Field; 1]) -> Self {
+        Self {
+            inner: fields[0] as u32
+        }
+    }
+}
+
+impl FromField for EventSelector {
+    fn from_field(field: Field) -> Self {
+        Self { inner: field as u32 }
+    }
+}
+
+impl ToField for EventSelector {
+    fn to_field(self) -> Field {
+        self.inner as Field
+    }
+}
+
+impl Empty for EventSelector {
+    fn empty() -> Self {
+        Self { inner: 0 as u32 }
+    }
+}
+
+impl EventSelector {
+    pub fn from_u32(value: u32) -> Self {
+        Self { inner: value }
+    }
+
+    pub fn from_signature<N>(signature: str<N>) -> Self {
+        let bytes = signature.as_bytes();
+        let hash = dep::std::hash::keccak256(bytes, bytes.len() as u32);
+
+        let mut selector_be_bytes = [0; SELECTOR_SIZE];
+        for i in 0..SELECTOR_SIZE {
+            selector_be_bytes[i] = hash[i];
+        }
+
+        EventSelector::from_field(field_from_bytes(selector_be_bytes, true))
+    }
+
+    pub fn zero() -> Self {
+        Self { inner: 0 }
+    }
+}

noir/noir-repo/aztec_macros/src/lib.rs

@@ -7,7 +7,8 @@ use transforms::{
     contract_interface::{
         generate_contract_interface, stub_function, update_fn_signatures_in_contract_interface,
     },
-    events::{generate_selector_impl, transform_events},
+    event_interface::{generate_event_interface_impl, transform_event_abi},
+    // events::transform_events,
     functions::{
         check_for_public_args, export_fn_abi, transform_function, transform_unconstrained,
     },
@@ -72,6 +73,7 @@ fn transform(
         }
     }
 
+    generate_event_interface_impl(&mut ast).map_err(|err| (err.into(), file_id))?;
     generate_note_interface_impl(&mut ast).map_err(|err| (err.into(), file_id))?;
 
     Ok(ast)
@@ -101,13 +103,6 @@ fn transform_module(
         generate_storage_layout(module, storage_struct_name.clone(), module_name)?;
     }
 
-    for structure in module.types.iter_mut() {
-        if structure.attributes.iter().any(|attr| is_custom_attribute(attr, "aztec(event)")) {
-            module.impls.push(generate_selector_impl(structure));
-            has_transformed_module = true;
-        }
-    }
-
     let has_initializer = module.functions.iter().any(|func| {
         func.def
             .attributes
@@ -222,7 +217,9 @@ fn transform_hir(
     context: &mut HirContext,
 ) -> Result<(), (AztecMacroError, FileId)> {
     if has_aztec_dependency(crate_id, context) {
-        transform_events(crate_id, context)?;
+        // The old event transformer is commented out but still kept for reference
+        // transform_events(crate_id, context)?;
+        transform_event_abi(crate_id, context)?;
         inject_compute_note_hash_and_optionally_a_nullifier(crate_id, context)?;
         assign_storage_slots(crate_id, context)?;
         inject_note_exports(crate_id, context)?;