From aaa566621157108cf07afc42131b40022ed3b8e9 Mon Sep 17 00:00:00 2001
From: Pearson White <pearson.white@nethermind.io>
Date: Wed, 23 Oct 2024 16:40:58 -0400
Subject: [PATCH] feature(blockifier): add emit_event cairo native syscall

---
 .../src/execution/native/syscall_handler.rs   | 31 ++++++++++++++++---
 .../syscalls/syscall_tests/emit_event.rs      |  9 ++++--
 2 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/crates/blockifier/src/execution/native/syscall_handler.rs b/crates/blockifier/src/execution/native/syscall_handler.rs
index a4ed00e23d4..65c958b9132 100644
--- a/crates/blockifier/src/execution/native/syscall_handler.rs
+++ b/crates/blockifier/src/execution/native/syscall_handler.rs
@@ -13,11 +13,13 @@ use cairo_native::starknet::{
 use cairo_vm::vm::runners::cairo_runner::ExecutionResources;
 use starknet_api::core::{ContractAddress, EntryPointSelector};
 use starknet_api::state::StorageKey;
+use starknet_api::transaction::{EventContent, EventData, EventKey};
 use starknet_types_core::felt::Felt;
 
 use crate::execution::call_info::{CallInfo, OrderedEvent, OrderedL2ToL1Message, Retdata};
 use crate::execution::entry_point::{CallEntryPoint, EntryPointExecutionContext};
 use crate::execution::native::utils::encode_str_as_felts;
+use crate::execution::syscalls::exceeds_event_size_limit;
 use crate::execution::syscalls::hint_processor::OUT_OF_GAS_ERROR;
 use crate::state::state_api::State;
 
@@ -196,11 +198,32 @@ impl<'state> StarknetSyscallHandler for &mut NativeSyscallHandler<'state> {
 
     fn emit_event(
         &mut self,
-        _keys: &[Felt],
-        _data: &[Felt],
-        _remaining_gas: &mut u128,
+        keys: &[Felt],
+        data: &[Felt],
+        remaining_gas: &mut u128,
     ) -> SyscallResult<()> {
-        todo!("Implement emit_event syscall.");
+        self.substract_syscall_gas_cost(
+            remaining_gas,
+            self.context.gas_costs().emit_event_gas_cost,
+        )?;
+
+        let order = self.context.n_emitted_events;
+        let event = EventContent {
+            keys: keys.iter().copied().map(EventKey).collect(),
+            data: EventData(data.to_vec()),
+        };
+
+        exceeds_event_size_limit(
+            self.context.versioned_constants(),
+            self.context.n_emitted_events + 1,
+            &event,
+        )
+        .expect("Number of events exceeded the size limit.");
+
+        self.events.push(OrderedEvent { order, event });
+        self.context.n_emitted_events += 1;
+
+        Ok(())
     }
 
     fn send_message_to_l1(
diff --git a/crates/blockifier/src/execution/syscalls/syscall_tests/emit_event.rs b/crates/blockifier/src/execution/syscalls/syscall_tests/emit_event.rs
index 3913e47014f..05e9230e416 100644
--- a/crates/blockifier/src/execution/syscalls/syscall_tests/emit_event.rs
+++ b/crates/blockifier/src/execution/syscalls/syscall_tests/emit_event.rs
@@ -24,11 +24,11 @@ const DATA: [Felt; 3] = [
 ];
 const N_EMITTED_EVENTS: [Felt; 1] = [Felt::from_hex_unchecked("0x1")];
 
+#[test_case(FeatureContract::TestContract(CairoVersion::Native), 58930; "Native")]
 #[test_case(FeatureContract::TestContract(CairoVersion::Cairo1), 48930; "VM")]
 fn positive_flow(test_contract: FeatureContract, expected_gas: u64) {
-    // TODO(Ori, 1/2/2024): Write an indicative expect message explaining why the conversion
-    // works.
-    let call_info = emit_events(test_contract, &N_EMITTED_EVENTS, &KEYS, &DATA).unwrap();
+    let call_info = emit_events(test_contract, &N_EMITTED_EVENTS, &KEYS, &DATA)
+        .expect("emit_events failed with valued parameters");
     let event = EventContent {
         keys: KEYS.into_iter().map(EventKey).collect(),
         data: EventData(DATA.to_vec()),
@@ -44,6 +44,7 @@ fn positive_flow(test_contract: FeatureContract, expected_gas: u64) {
     );
 }
 
+#[test_case(FeatureContract::TestContract(CairoVersion::Native); "Native")]
 #[test_case(FeatureContract::TestContract(CairoVersion::Cairo1); "VM")]
 fn data_length_exceeds_limit(test_contract: FeatureContract) {
     let versioned_constants = VersionedConstants::create_for_testing();
@@ -58,6 +59,7 @@ fn data_length_exceeds_limit(test_contract: FeatureContract) {
     assert!(error.to_string().contains(&expected_error.to_string()));
 }
 
+#[test_case(FeatureContract::TestContract(CairoVersion::Native); "Native")]
 #[test_case(FeatureContract::TestContract(CairoVersion::Cairo1); "VM")]
 fn keys_length_exceeds_limit(test_contract: FeatureContract) {
     let versioned_constants = VersionedConstants::create_for_testing();
@@ -73,6 +75,7 @@ fn keys_length_exceeds_limit(test_contract: FeatureContract) {
     assert!(error.to_string().contains(&expected_error.to_string()));
 }
 
+#[test_case(FeatureContract::TestContract(CairoVersion::Native); "Native")]
 #[test_case(FeatureContract::TestContract(CairoVersion::Cairo1); "VM")]
 fn event_number_exceeds_limit(test_contract: FeatureContract) {
     let versioned_constants = VersionedConstants::create_for_testing();