implement contract events (#2161)

* implement contract events

* update runtime

* renaming

* update test code hash

* improve complexity details

* add deposit event base cost

* add test

* Revert "add deposit event base cost"

This reverts commit 58ec010.

* update test

* Revert "update test"

This reverts commit 6fe61a5.

* Revert "Revert "add deposit event base cost""

This reverts commit 145e8a9.

* Fix format a bit

node/runtime/src/lib.rs

@@ -59,8 +59,8 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	spec_name: create_runtime_str!("node"),
 	impl_name: create_runtime_str!("substrate-node"),
 	authoring_version: 10,
-	spec_version: 56,
-	impl_version: 60,
+	spec_version: 57,
+	impl_version: 57,
 	apis: RUNTIME_API_VERSIONS,
 };
 

srml/contract/COMPLEXITY.md

@@ -275,6 +275,17 @@ This function receives a `data` buffer as an argument. Execution of the function
 
 **complexity**: The complexity of this function is proportional to the size of the `data` buffer.
 
+## ext_deposit_event
+
+This function receives a `data` buffer as an argument. Execution of the function consists of the following steps:
+
+1. Loading `data` buffer from the sandbox memory (see sandboxing memory get),
+2. Insert to nested context execution
+3. Copies from nested to underlying contexts
+4. Call system deposit event
+
+**complexity**: The complexity of this function is proportional to the size of the `data` buffer.
+
 ## ext_caller
 
 This function serializes the address of the caller into the scratch buffer.

srml/contract/src/exec.rs

@@ -89,7 +89,6 @@ pub trait Ext {
 	/// Returns a reference to the account id of the current contract.
 	fn address(&self) -> &AccountIdOf<Self::T>;
 
-
 	/// Returns the balance of the current contract.
 	///
 	/// The `value_transferred` is already added.
@@ -103,6 +102,9 @@ pub trait Ext {
 
 	/// Returns a reference to the random seed for the current block
 	fn random_seed(&self) -> &SeedOf<Self::T>;
+
+	/// Deposit an event.
+	fn deposit_event(&mut self, data: Vec<u8>);
 }
 
 /// Loader is a companion of the `Vm` trait. It loads an appropriate abstract
@@ -617,6 +619,10 @@ where
 	fn now(&self) -> &T::Moment {
 		&self.timestamp
 	}
+
+	fn deposit_event(&mut self, data: Vec<u8>) {
+		self.ctx.events.push(RawEvent::Contract(self.ctx.self_account.clone(), data));
+	}
 }
 
 /// These tests exercise the executive layer.

srml/contract/src/lib.rs

@@ -405,6 +405,9 @@ decl_event! {
 		/// A call was dispatched from the given account. The bool signals whether it was
 		/// successful execution or not.
 		Dispatched(AccountId, bool),
+
+		/// An event from contract of account.
+		Contract(AccountId, Vec<u8>),
 	}
 }
 
@@ -503,6 +506,12 @@ pub struct Schedule<Gas> {
 	/// Gas cost per one byte returned.
 	pub return_data_per_byte_cost: Gas,
 
+	/// Gas cost to deposit an event; the per-byte portion.
+	pub event_data_per_byte_cost: Gas,
+
+	/// Gas cost to deposit an event; the base.
+	pub event_data_base_cost: Gas,
+
 	/// Gas cost per one byte read from the sandbox memory.
 	pub sandbox_data_read_cost: Gas,
 
@@ -528,6 +537,8 @@ impl<Gas: As<u64>> Default for Schedule<Gas> {
 			grow_mem_cost: Gas::sa(1),
 			regular_op_cost: Gas::sa(1),
 			return_data_per_byte_cost: Gas::sa(1),
+			event_data_per_byte_cost: Gas::sa(1),
+			event_data_base_cost: Gas::sa(1),
 			sandbox_data_read_cost: Gas::sa(1),
 			sandbox_data_write_cost: Gas::sa(1),
 			max_stack_height: 64 * 1024,

srml/contract/src/tests.rs

@@ -291,10 +291,15 @@ fn account_removal_removes_storage() {
 const CODE_RETURN_FROM_START_FN: &str = r#"
 (module
 	(import "env" "ext_return" (func $ext_return (param i32 i32)))
+	(import "env" "ext_deposit_event" (func $ext_deposit_event (param i32 i32)))
 	(import "env" "memory" (memory 1 1))
 
 	(start $start)
 	(func $start
+		(call $ext_deposit_event
+			(i32.const 8)
+			(i32.const 4)
+		)
 		(call $ext_return
 			(i32.const 8)
 			(i32.const 4)
@@ -310,10 +315,10 @@ const CODE_RETURN_FROM_START_FN: &str = r#"
 	(data (i32.const 8) "\01\02\03\04")
 )
 "#;
-const HASH_RETURN_FROM_START_FN: [u8; 32] = hex!("e6411d12daa2a19e4e9c7d8306c31c7d53a352cb8ed84385c8a1d48fc232e708");
+const HASH_RETURN_FROM_START_FN: [u8; 32] = hex!("abb4194bdea47b2904fe90b4fd674bd40d96f423956627df8c39d2b1a791ab9d");
 
 #[test]
-fn instantiate_and_call() {
+fn instantiate_and_call_and_deposit_event() {
 	let wasm = wabt::wat2wasm(CODE_RETURN_FROM_START_FN).unwrap();
 
 	with_externalities(
@@ -327,13 +332,14 @@ fn instantiate_and_call() {
 				wasm,
 			));
 
-			assert_ok!(Contract::create(
+			// Check at the end to get hash on error easily
+			let creation = Contract::create(
 				Origin::signed(ALICE),
 				100,
 				100_000,
 				HASH_RETURN_FROM_START_FN.into(),
 				vec![],
-			));
+			);
 
 			assert_eq!(System::events(), vec![
 				EventRecord {
@@ -354,12 +360,17 @@ fn instantiate_and_call() {
 					phase: Phase::ApplyExtrinsic(0),
 					event: MetaEvent::contract(RawEvent::Transfer(ALICE, BOB, 100))
 				},
+				EventRecord {
+					phase: Phase::ApplyExtrinsic(0),
+					event: MetaEvent::contract(RawEvent::Contract(BOB, vec![1, 2, 3, 4]))
+				},
 				EventRecord {
 					phase: Phase::ApplyExtrinsic(0),
 					event: MetaEvent::contract(RawEvent::Instantiated(ALICE, BOB))
 				}
 			]);
 
+			assert_ok!(creation);
 			assert!(AccountInfoOf::<Test>::exists(BOB));
 		},
 	);

srml/contract/src/wasm/mod.rs

@@ -203,6 +203,7 @@ mod tests {
 		creates: Vec<CreateEntry>,
 		transfers: Vec<TransferEntry>,
 		dispatches: Vec<DispatchEntry>,
+		events: Vec<Vec<u8>>,
 		next_account_id: u64,
 		random_seed: H256,
 	}
@@ -276,6 +277,10 @@ mod tests {
 		fn random_seed(&self) -> &H256{
 			&self.random_seed
 		}
+
+		fn deposit_event(&mut self, data: Vec<u8>) {
+			self.events.push(data)
+		}
 	}
 
 	fn execute<E: Ext>(
@@ -1166,4 +1171,43 @@ mod tests {
 		.unwrap();
 	}
 
+	const CODE_DEPOSIT_EVENT: &str = r#"
+(module
+	(import "env" "ext_deposit_event" (func $ext_deposit_event (param i32 i32)))
+	(import "env" "memory" (memory 1 1))
+
+	(func (export "call")
+		(call $ext_deposit_event
+			(i32.const 8) ;; Pointer to the start of encoded call buffer
+			(i32.const 13) ;; Length of the buffer
+		)
+	)
+	(func (export "deploy"))
+
+	(data (i32.const 8) "\00\01\2A\00\00\00\00\00\00\00\E5\14\00")
+)
+"#;
+
+	#[test]
+	fn deposit_event() {
+		// This test can fail due to the encoding changes. In case it becomes too annoying
+		// let's rewrite so as we use this module controlled call or we serialize it in runtime.
+
+		let mut mock_ext = MockExt::default();
+		let mut gas_meter = GasMeter::with_limit(50_000, 1);
+		execute(
+			CODE_DEPOSIT_EVENT,
+			&[],
+			&mut Vec::new(),
+			&mut mock_ext,
+			&mut gas_meter
+		)
+		.unwrap();
+		assert_eq!(gas_meter.gas_left(), 50_000
+			- 4      // Explicit
+			- 13 - 1 // Deposit event
+			- 13     // read memory
+		);
+		assert_eq!(mock_ext.events, vec![vec![0, 1, 42, 0, 0, 0, 0, 0, 0, 0, 229, 20, 0]]);
+	}
 }

srml/contract/src/wasm/runtime.rs

@@ -24,7 +24,7 @@ use system;
 use rstd::prelude::*;
 use rstd::mem;
 use parity_codec::{Decode, Encode};
-use runtime_primitives::traits::{As, CheckedMul, Bounded};
+use runtime_primitives::traits::{As, CheckedMul, CheckedAdd, Bounded};
 
 /// Enumerates all possible *special* trap conditions.
 ///
@@ -108,6 +108,9 @@ pub enum RuntimeToken<Gas> {
 	ReturnData(u32),
 	/// Dispatch fee calculated by `T::ComputeDispatchFee`.
 	ComputedDispatchFee(Gas),
+	/// The given number of bytes is read from the sandbox memory and
+	/// deposit in as an event.
+	DepositEvent(u32),
 }
 
 impl<T: Trait> Token<T> for RuntimeToken<T::Gas> {
@@ -126,6 +129,10 @@ impl<T: Trait> Token<T> for RuntimeToken<T::Gas> {
 			ReturnData(byte_count) => metadata
 				.return_data_per_byte_cost
 				.checked_mul(&<T::Gas as As<u32>>::sa(byte_count)),
+			DepositEvent(byte_count) => metadata
+				.event_data_per_byte_cost
+				.checked_mul(&<T::Gas as As<u32>>::sa(byte_count))
+				.and_then(|e| e.checked_add(&metadata.event_data_base_cost)),
 			ComputedDispatchFee(gas) => Some(gas),
 		};
 
@@ -582,4 +589,23 @@ define_env!(Env, <E: Ext>,
 
 		Ok(())
 	},
+
+	// Deposit a contract event with the data buffer.
+	ext_deposit_event(ctx, data_ptr: u32, data_len: u32) => {
+		match ctx
+			.gas_meter
+			.charge(
+				ctx.schedule,
+				RuntimeToken::DepositEvent(data_len)
+			)
+		{
+			GasMeterResult::Proceed => (),
+			GasMeterResult::OutOfGas => return Err(sandbox::HostError),
+		}
+
+		let event_data = read_sandbox_memory(ctx, data_ptr, data_len)?;
+		ctx.ext.deposit_event(event_data);
+
+		Ok(())
+	},
 );

srml/support/test/tests/instance.rs

@@ -435,8 +435,6 @@ fn storage_instance_independance() {
 	});
 }
 
-// TODO TODO: check configuration doublemapstorage in instances
-
 #[test]
 fn storage_with_instance_basic_operation() {
 	with_externalities(&mut new_test_ext(), || {