contracts: Reduce the API surface (#8359)

* contracts: Remove types and storage from the public interface

* contracts: Remove current_schedule() getter

* contracts: Improve documentation

* Update README.md

* Fix integration test

substrate/frame/contracts/src/benchmarking/code.rs

@@ -24,9 +24,7 @@
 //! we define this simple definition of a contract that can be passed to `create_code` that
 //! compiles it down into a `WasmModule` that can be used as a contract's code.
 
-use crate::Config;
-use crate::Pallet as Contracts;
-
+use crate::{Config, CurrentSchedule};
 use parity_wasm::elements::{
 	Instruction, Instructions, FuncBody, ValueType, BlockType, Section, CustomSection,
 };
@@ -225,7 +223,7 @@ where
 		if def.inject_stack_metering {
 			code = inject_limiter(
 				code,
-				Contracts::<T>::current_schedule().limits.stack_height
+				<CurrentSchedule<T>>::get().limits.stack_height
 			)
 			.unwrap();
 		}
@@ -505,5 +503,5 @@ where
 	T: Config,
 	T::AccountId: UncheckedFrom<T::Hash> + AsRef<[u8]>,
 {
-	Contracts::<T>::current_schedule().limits.memory_pages
+	<CurrentSchedule<T>>::get().limits.memory_pages
 }

substrate/frame/contracts/src/benchmarking/mod.rs

@@ -36,6 +36,7 @@ use self::{
 	},
 	sandbox::Sandbox,
 };
+use codec::Encode;
 use frame_benchmarking::{benchmarks, account, whitelisted_caller, impl_benchmark_test_suite};
 use frame_system::{Pallet as System, RawOrigin};
 use parity_wasm::elements::{Instruction, ValueType, BlockType};
@@ -313,7 +314,7 @@ benchmarks! {
 		let WasmModule { code, hash, .. } = WasmModule::<T>::sized(c * 1024);
 		Contracts::<T>::store_code_raw(code)?;
 		let mut module = PrefabWasmModule::from_storage_noinstr(hash)?;
-		let schedule = Contracts::<T>::current_schedule();
+		let schedule = <CurrentSchedule<T>>::get();
 	}: {
 		Contracts::<T>::reinstrument_module(&mut module, &schedule)?;
 	}
@@ -936,7 +937,7 @@ benchmarks! {
 	seal_random {
 		let r in 0 .. API_BENCHMARK_BATCHES;
 		let pages = code::max_pages::<T>();
-		let subject_len = Contracts::<T>::current_schedule().limits.subject_len;
+		let subject_len = <CurrentSchedule<T>>::get().limits.subject_len;
 		assert!(subject_len < 1024);
 		let code = WasmModule::<T>::from(ModuleDefinition {
 			memory: Some(ImportedMemory::max::<T>()),
@@ -992,7 +993,7 @@ benchmarks! {
 	// `t`: Number of topics
 	// `n`: Size of event payload in kb
 	seal_deposit_event_per_topic_and_kb {
-		let t in 0 .. Contracts::<T>::current_schedule().limits.event_topics;
+		let t in 0 .. <CurrentSchedule<T>>::get().limits.event_topics;
 		let n in 0 .. T::MaxValueSize::get() / 1024;
 		let mut topics = (0..API_BENCHMARK_BATCH_SIZE)
 			.map(|n| (n * t..n * t + t).map(|i| T::Hashing::hash_of(&i)).collect::<Vec<_>>().encode())
@@ -1922,7 +1923,7 @@ benchmarks! {
 
 	// w_br_table_per_entry = w_bench
 	instr_br_table_per_entry {
-		let e in 1 .. Contracts::<T>::current_schedule().limits.br_table_size;
+		let e in 1 .. <CurrentSchedule<T>>::get().limits.br_table_size;
 		let entry: Vec<u32> = [0, 1].iter()
 			.cloned()
 			.cycle()
@@ -1978,7 +1979,7 @@ benchmarks! {
 	// w_call_indrect = w_bench - 3 * w_param
 	instr_call_indirect {
 		let r in 0 .. INSTR_BENCHMARK_BATCHES;
-		let num_elements = Contracts::<T>::current_schedule().limits.table_size;
+		let num_elements = <CurrentSchedule<T>>::get().limits.table_size;
 		use self::code::TableSegment;
 		let mut sbox = Sandbox::from(&WasmModule::<T>::from(ModuleDefinition {
 			// We need to make use of the stack here in order to trigger stack height
@@ -2008,8 +2009,8 @@ benchmarks! {
 	// linearly depend on the amount of parameters to this function.
 	// Please note that this is not necessary with a direct call.
 	instr_call_indirect_per_param {
-		let p in 0 .. Contracts::<T>::current_schedule().limits.parameters;
-		let num_elements = Contracts::<T>::current_schedule().limits.table_size;
+		let p in 0 .. <CurrentSchedule<T>>::get().limits.parameters;
+		let num_elements = <CurrentSchedule<T>>::get().limits.table_size;
 		use self::code::TableSegment;
 		let mut sbox = Sandbox::from(&WasmModule::<T>::from(ModuleDefinition {
 			// We need to make use of the stack here in order to trigger stack height
@@ -2039,7 +2040,7 @@ benchmarks! {
 	// w_local_get = w_bench - 1 * w_param
 	instr_local_get {
 		let r in 0 .. INSTR_BENCHMARK_BATCHES;
-		let max_locals = Contracts::<T>::current_schedule().limits.stack_height;
+		let max_locals = <CurrentSchedule<T>>::get().limits.stack_height;
 		let mut call_body = body::repeated_dyn(r * INSTR_BENCHMARK_BATCH_SIZE, vec![
 			RandomGetLocal(0, max_locals),
 			Regular(Instruction::Drop),
@@ -2056,7 +2057,7 @@ benchmarks! {
 	// w_local_set = w_bench - 1 * w_param
 	instr_local_set {
 		let r in 0 .. INSTR_BENCHMARK_BATCHES;
-		let max_locals = Contracts::<T>::current_schedule().limits.stack_height;
+		let max_locals = <CurrentSchedule<T>>::get().limits.stack_height;
 		let mut call_body = body::repeated_dyn(r * INSTR_BENCHMARK_BATCH_SIZE, vec![
 			RandomI64Repeated(1),
 			RandomSetLocal(0, max_locals),
@@ -2073,7 +2074,7 @@ benchmarks! {
 	// w_local_tee = w_bench - 2 * w_param
 	instr_local_tee {
 		let r in 0 .. INSTR_BENCHMARK_BATCHES;
-		let max_locals = Contracts::<T>::current_schedule().limits.stack_height;
+		let max_locals = <CurrentSchedule<T>>::get().limits.stack_height;
 		let mut call_body = body::repeated_dyn(r * INSTR_BENCHMARK_BATCH_SIZE, vec![
 			RandomI64Repeated(1),
 			RandomTeeLocal(0, max_locals),
@@ -2091,7 +2092,7 @@ benchmarks! {
 	// w_global_get = w_bench - 1 * w_param
 	instr_global_get {
 		let r in 0 .. INSTR_BENCHMARK_BATCHES;
-		let max_globals = Contracts::<T>::current_schedule().limits.globals;
+		let max_globals = <CurrentSchedule<T>>::get().limits.globals;
 		let mut sbox = Sandbox::from(&WasmModule::<T>::from(ModuleDefinition {
 			call_body: Some(body::repeated_dyn(r * INSTR_BENCHMARK_BATCH_SIZE, vec![
 				RandomGetGlobal(0, max_globals),
@@ -2107,7 +2108,7 @@ benchmarks! {
 	// w_global_set = w_bench - 1 * w_param
 	instr_global_set {
 		let r in 0 .. INSTR_BENCHMARK_BATCHES;
-		let max_globals = Contracts::<T>::current_schedule().limits.globals;
+		let max_globals = <CurrentSchedule<T>>::get().limits.globals;
 		let mut sbox = Sandbox::from(&WasmModule::<T>::from(ModuleDefinition {
 			call_body: Some(body::repeated_dyn(r * INSTR_BENCHMARK_BATCH_SIZE, vec![
 				RandomI64Repeated(1),

substrate/frame/contracts/src/chain_extension.rs

@@ -47,6 +47,12 @@
 //! induces. In order to be able to charge the correct weight for the functions defined
 //! by a chain extension benchmarks must be written, too. In the near future this crate
 //! will provide the means for easier creation of those specialized benchmarks.
+//!
+//! # Example
+//!
+//! The ink! repository maintains an
+//! [end-to-end example](https://github.com/paritytech/ink/tree/master/examples/rand-extension)
+//! on how to use a chain extension in order to provide new features to ink! contracts.
 
 use crate::{
 	Error,
@@ -141,8 +147,8 @@ pub enum RetVal {
 
 /// Grants the chain extension access to its parameters and execution environment.
 ///
-/// It uses the typestate pattern to enforce the correct usage of the parameters passed
-/// to the chain extension.
+/// It uses [typestate programming](https://docs.rust-embedded.org/book/static-guarantees/typestate-programming.html)
+/// to enforce the correct usage of the parameters passed to the chain extension.
 pub struct Environment<'a, 'b, E: Ext, S: state::State> {
 	/// The actual data of this type.
 	inner: Inner<'a, 'b, E>,
@@ -376,6 +382,8 @@ mod state {
 	pub trait BufIn: State {}
 	pub trait BufOut: State {}
 
+	/// The initial state of an [`Environment`](`super::Environment`).
+	/// See [typestate programming](https://docs.rust-embedded.org/book/static-guarantees/typestate-programming.html).
 	pub enum Init {}
 	pub enum OnlyIn {}
 	pub enum PrimInBufOut {}

substrate/frame/contracts/src/exec.rs

@@ -943,7 +943,7 @@ mod tests {
 			test_utils::{place_contract, set_balance, get_balance},
 		},
 		exec::ExportedFunction::*,
-		Error, Weight,
+		Error, Weight, CurrentSchedule,
 	};
 	use sp_runtime::DispatchError;
 	use assert_matches::assert_matches;
@@ -1139,7 +1139,7 @@ mod tests {
 		});
 
 		ExtBuilder::default().build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			place_contract(&BOB, exec_ch);
 
@@ -1189,7 +1189,7 @@ mod tests {
 		);
 
 		ExtBuilder::default().build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(origin.clone(), &schedule);
 			place_contract(&BOB, return_ch);
 			set_balance(&origin, 100);
@@ -1249,7 +1249,7 @@ mod tests {
 		);
 
 		ExtBuilder::default().build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(origin, &schedule);
 			place_contract(&BOB, return_ch);
 
@@ -1278,7 +1278,7 @@ mod tests {
 		);
 
 		ExtBuilder::default().build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(origin, &schedule);
 			place_contract(&BOB, return_ch);
 
@@ -1304,7 +1304,7 @@ mod tests {
 
 		// This one tests passing the input data into a contract via call.
 		ExtBuilder::default().build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			place_contract(&BOB, input_data_ch);
 
@@ -1327,7 +1327,7 @@ mod tests {
 
 		// This one tests passing the input data into a contract via instantiate.
 		ExtBuilder::default().build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let subsistence = Contracts::<Test>::subsistence_threshold();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			let mut gas_meter = GasMeter::<Test>::new(GAS_LIMIT);
@@ -1380,7 +1380,7 @@ mod tests {
 		});
 
 		ExtBuilder::default().build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			set_balance(&BOB, 1);
 			place_contract(&BOB, recurse_ch);
@@ -1428,7 +1428,7 @@ mod tests {
 		});
 
 		ExtBuilder::default().build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(origin.clone(), &schedule);
 			place_contract(&dest, bob_ch);
 			place_contract(&CHARLIE, charlie_ch);
@@ -1466,7 +1466,7 @@ mod tests {
 		});
 
 		ExtBuilder::default().build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			place_contract(&BOB, bob_ch);
 			place_contract(&CHARLIE, charlie_ch);
@@ -1487,7 +1487,7 @@ mod tests {
 		let dummy_ch = MockLoader::insert(Constructor, |_, _| exec_success());
 
 		ExtBuilder::default().existential_deposit(15).build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			let mut gas_meter = GasMeter::<Test>::new(GAS_LIMIT);
 			let executable = MockExecutable::from_storage(
@@ -1515,7 +1515,7 @@ mod tests {
 		);
 
 		ExtBuilder::default().existential_deposit(15).build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			let mut gas_meter = GasMeter::<Test>::new(GAS_LIMIT);
 			let executable = MockExecutable::from_storage(
@@ -1551,7 +1551,7 @@ mod tests {
 		);
 
 		ExtBuilder::default().existential_deposit(15).build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			let mut gas_meter = GasMeter::<Test>::new(GAS_LIMIT);
 			let executable = MockExecutable::from_storage(
@@ -1599,7 +1599,7 @@ mod tests {
 		});
 
 		ExtBuilder::default().existential_deposit(15).build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			set_balance(&ALICE, Contracts::<Test>::subsistence_threshold() * 100);
 			place_contract(&BOB, instantiator_ch);
@@ -1648,7 +1648,7 @@ mod tests {
 		});
 
 		ExtBuilder::default().existential_deposit(15).build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			set_balance(&ALICE, 1000);
 			set_balance(&BOB, 100);
@@ -1676,7 +1676,7 @@ mod tests {
 			.existential_deposit(15)
 			.build()
 			.execute_with(|| {
-				let schedule = Contracts::current_schedule();
+				let schedule = <CurrentSchedule<Test>>::get();
 				let mut ctx = MockContext::top_level(ALICE, &schedule);
 				let mut gas_meter = GasMeter::<Test>::new(GAS_LIMIT);
 				let executable = MockExecutable::from_storage(
@@ -1715,7 +1715,7 @@ mod tests {
 
 		ExtBuilder::default().build().execute_with(|| {
 			let subsistence = Contracts::<Test>::subsistence_threshold();
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			let mut gas_meter = GasMeter::<Test>::new(GAS_LIMIT);
 			let executable = MockExecutable::from_storage(
@@ -1747,7 +1747,7 @@ mod tests {
 
 		ExtBuilder::default().build().execute_with(|| {
 			let subsistence = Contracts::<Test>::subsistence_threshold();
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			let mut gas_meter = GasMeter::<Test>::new(GAS_LIMIT);
 			set_balance(&ALICE, subsistence * 10);
@@ -1795,7 +1795,7 @@ mod tests {
 
 		ExtBuilder::default().build().execute_with(|| {
 			let subsistence = Contracts::<Test>::subsistence_threshold();
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			let mut gas_meter = GasMeter::<Test>::new(GAS_LIMIT);
 			set_balance(&ALICE, subsistence * 100);

substrate/frame/contracts/src/lib.rs

@@ -24,12 +24,12 @@
 //!
 //! ## Overview
 //!
-//! This module extends accounts based on the `Currency` trait to have smart-contract functionality. It can
-//! be used with other modules that implement accounts based on `Currency`. These "smart-contract accounts"
+//! This module extends accounts based on the [`Currency`] trait to have smart-contract functionality. It can
+//! be used with other modules that implement accounts based on [`Currency`]. These "smart-contract accounts"
 //! have the ability to instantiate smart-contracts and make calls to other contract and non-contract accounts.
 //!
-//! The smart-contract code is stored once in a `code_cache`, and later retrievable via its `code_hash`.
-//! This means that multiple smart-contracts can be instantiated from the same `code_cache`, without replicating
+//! The smart-contract code is stored once in a code cache, and later retrievable via its hash.
+//! This means that multiple smart-contracts can be instantiated from the same hash, without replicating
 //! the code each time.
 //!
 //! When a smart-contract is called, its associated code is retrieved via the code hash and gets executed.
@@ -59,12 +59,17 @@
 //!
 //! ### Dispatchable functions
 //!
-//! * `instantiate_with_code` - Deploys a new contract from the supplied wasm binary, optionally transferring
-//! some balance. This instantiates a new smart contract account and calls its contract deploy
-//! handler to initialize the contract.
-//! * `instantiate` - The same as `instantiate_with_code` but instead of uploading new code an
-//! existing `code_hash` is supplied.
-//! * `call` - Makes a call to an account, optionally transferring some balance.
+//! * [`Pallet::update_schedule`] -
+//! ([Root Origin](https://substrate.dev/docs/en/knowledgebase/runtime/origin) Only) -
+//! Set a new [`Schedule`].
+//! * [`Pallet::instantiate_with_code`] - Deploys a new contract from the supplied wasm binary,
+//! optionally transferring
+//! some balance. This instantiates a new smart contract account with the supplied code and
+//! calls its constructor to initialize the contract.
+//! * [`Pallet::instantiate`] - The same as `instantiate_with_code` but instead of uploading new
+//! code an existing `code_hash` is supplied.
+//! * [`Pallet::call`] - Makes a call to an account, optionally transferring some balance.
+//! * [`Pallet::claim_surcharge`] - Evict a contract that cannot pay rent anymore.
 //!
 //! ## Usage
 //!
@@ -98,29 +103,24 @@ pub mod weights;
 #[cfg(test)]
 mod tests;
 
-pub use crate::{
-	wasm::PrefabWasmModule,
-	schedule::{Schedule, HostFnWeights, InstructionWeights, Limits},
-	pallet::*,
-};
+pub use crate::{pallet::*, schedule::Schedule};
 use crate::{
 	gas::GasMeter,
 	exec::{ExecutionContext, Executable},
 	rent::Rent,
-	storage::{Storage, DeletedContract},
+	storage::{Storage, DeletedContract, ContractInfo, AliveContractInfo, TombstoneContractInfo},
 	weights::WeightInfo,
+	wasm::PrefabWasmModule,
 };
 use sp_core::crypto::UncheckedFrom;
-use sp_std::{prelude::*, marker::PhantomData, fmt::Debug};
-use codec::{Codec, Encode, Decode};
+use sp_std::prelude::*;
 use sp_runtime::{
 	traits::{
-		Hash, StaticLookup, MaybeSerializeDeserialize, Member, Convert, Saturating, Zero,
+		Hash, StaticLookup, Convert, Saturating, Zero,
 	},
-	RuntimeDebug, Perbill,
+	Perbill,
 };
 use frame_support::{
-	storage::child::ChildInfo,
 	traits::{OnUnbalanced, Currency, Get, Time, Randomness},
 	weights::{Weight, PostDispatchInfo, WithPostDispatchInfo},
 };
@@ -129,16 +129,12 @@ use pallet_contracts_primitives::{
 	RentProjectionResult, GetStorageResult, ContractAccessError, ContractExecResult,
 };
 
-pub type CodeHash<T> = <T as frame_system::Config>::Hash;
-pub type TrieId = Vec<u8>;
-pub type BalanceOf<T> =
+type CodeHash<T> = <T as frame_system::Config>::Hash;
+type TrieId = Vec<u8>;
+type BalanceOf<T> =
 	<<T as Config>::Currency as Currency<<T as frame_system::Config>::AccountId>>::Balance;
-pub type NegativeImbalanceOf<T> =
+type NegativeImbalanceOf<T> =
 	<<T as Config>::Currency as Currency<<T as frame_system::Config>::AccountId>>::NegativeImbalance;
-pub type AliveContractInfo<T> =
-	RawAliveContractInfo<CodeHash<T>, BalanceOf<T>, <T as frame_system::Config>::BlockNumber>;
-pub type TombstoneContractInfo<T> =
-	RawTombstoneContractInfo<<T as frame_system::Config>::Hash, <T as frame_system::Config>::Hashing>;
 
 #[frame_support::pallet]
 pub mod pallet {
@@ -248,7 +244,6 @@ pub mod pallet {
 	}
 
 	#[pallet::pallet]
-	#[pallet::generate_store(pub(super) trait Store)]
 	pub struct Pallet<T>(PhantomData<T>);
 
 	#[pallet::hooks]
@@ -290,7 +285,7 @@ pub mod pallet {
 			schedule: Schedule<T>
 		) -> DispatchResultWithPostInfo {
 			ensure_root(origin)?;
-			if <Pallet<T>>::current_schedule().version > schedule.version {
+			if <CurrentSchedule<T>>::get().version > schedule.version {
 				Err(Error::<T>::InvalidScheduleVersion)?
 			}
 			Self::deposit_event(Event::ScheduleUpdated(schedule.version));
@@ -316,7 +311,7 @@ pub mod pallet {
 			let origin = ensure_signed(origin)?;
 			let dest = T::Lookup::lookup(dest)?;
 			let mut gas_meter = GasMeter::new(gas_limit);
-			let schedule = <Pallet<T>>::current_schedule();
+			let schedule = <CurrentSchedule<T>>::get();
 			let mut ctx = ExecutionContext::<T, PrefabWasmModule<T>>::top_level(origin, &schedule);
 			let (result, code_len) = match ctx.call(dest, value, &mut gas_meter, data) {
 				Ok((output, len)) => (Ok(output), len),
@@ -365,7 +360,7 @@ pub mod pallet {
 			let code_len = code.len() as u32;
 			ensure!(code_len <= T::MaxCodeSize::get(), Error::<T>::CodeTooLarge);
 			let mut gas_meter = GasMeter::new(gas_limit);
-			let schedule = <Pallet<T>>::current_schedule();
+			let schedule = <CurrentSchedule<T>>::get();
 			let executable = PrefabWasmModule::from_code(code, &schedule)?;
 			let code_len = executable.code_len();
 			ensure!(code_len <= T::MaxCodeSize::get(), Error::<T>::CodeTooLarge);
@@ -397,7 +392,7 @@ pub mod pallet {
 		) -> DispatchResultWithPostInfo {
 			let origin = ensure_signed(origin)?;
 			let mut gas_meter = GasMeter::new(gas_limit);
-			let schedule = <Pallet<T>>::current_schedule();
+			let schedule = <CurrentSchedule<T>>::get();
 			let executable = PrefabWasmModule::from_storage(code_hash, &schedule, &mut gas_meter)?;
 			let mut ctx = ExecutionContext::<T, PrefabWasmModule<T>>::top_level(origin, &schedule);
 			let code_len = executable.code_len();
@@ -614,33 +609,33 @@ pub mod pallet {
 
 	/// Current cost schedule for contracts.
 	#[pallet::storage]
-	#[pallet::getter(fn current_schedule)]
-	pub(super) type CurrentSchedule<T: Config> = StorageValue<_, Schedule<T>, ValueQuery>;
+	pub(crate) type CurrentSchedule<T: Config> = StorageValue<_, Schedule<T>, ValueQuery>;
 
 	/// A mapping from an original code hash to the original code, untouched by instrumentation.
 	#[pallet::storage]
-	pub type PristineCode<T: Config> = StorageMap<_, Identity, CodeHash<T>, Vec<u8>>;
+	pub(crate) type PristineCode<T: Config> = StorageMap<_, Identity, CodeHash<T>, Vec<u8>>;
 
 	/// A mapping between an original code hash and instrumented wasm code, ready for execution.
 	#[pallet::storage]
-	pub type CodeStorage<T: Config> = StorageMap<_, Identity, CodeHash<T>, PrefabWasmModule<T>>;
+	pub(crate) type CodeStorage<T: Config> = StorageMap<_, Identity, CodeHash<T>, PrefabWasmModule<T>>;
 
 	/// The subtrie counter.
 	#[pallet::storage]
-	pub type AccountCounter<T: Config> = StorageValue<_, u64, ValueQuery>;
+	pub(crate) type AccountCounter<T: Config> = StorageValue<_, u64, ValueQuery>;
 
 	/// The code associated with a given account.
 	///
 	/// TWOX-NOTE: SAFE since `AccountId` is a secure hash.
 	#[pallet::storage]
-	pub type ContractInfoOf<T: Config> = StorageMap<_, Twox64Concat, T::AccountId, ContractInfo<T>>;
+	pub(crate) type ContractInfoOf<T: Config> = StorageMap<_, Twox64Concat, T::AccountId, ContractInfo<T>>;
 
 	/// Evicted contracts that await child trie deletion.
 	///
 	/// Child trie deletion is a heavy operation depending on the amount of storage items
 	/// stored in said trie. Therefore this operation is performed lazily in `on_initialize`.
 	#[pallet::storage]
-	pub type DeletionQueue<T: Config> = StorageValue<_, Vec<DeletedContract>, ValueQuery>;
+	pub(crate) type DeletionQueue<T: Config> = StorageValue<_, Vec<DeletedContract>, ValueQuery>;
+
 
 	#[pallet::genesis_config]
 	pub struct GenesisConfig<T: Config> {
@@ -683,7 +678,7 @@ where
 		input_data: Vec<u8>,
 	) -> ContractExecResult {
 		let mut gas_meter = GasMeter::new(gas_limit);
-		let schedule = <Pallet<T>>::current_schedule();
+		let schedule = <CurrentSchedule<T>>::get();
 		let mut ctx = ExecutionContext::<T, PrefabWasmModule<T>>::top_level(origin, &schedule);
 		let result = ctx.call(dest, value, &mut gas_meter, input_data);
 		let gas_consumed = gas_meter.gas_spent();
@@ -743,10 +738,24 @@ where
 		T::Currency::minimum_balance().saturating_add(T::TombstoneDeposit::get())
 	}
 
+	/// The in-memory size in bytes of the data structure associated with each contract.
+	///
+	/// The data structure is also put into storage for each contract. The in-storage size
+	/// is never larger than the in-memory representation and usually smaller due to compact
+	/// encoding and lack of padding.
+	///
+	/// # Note
+	///
+	/// This returns the in-memory size because the in-storage size (SCALE encoded) cannot
+	/// be efficiently determined. Treat this as an upper bound of the in-storage size.
+	pub fn contract_info_size() -> u32 {
+		sp_std::mem::size_of::<ContractInfo<T>>() as u32
+	}
+
 	/// Store code for benchmarks which does not check nor instrument the code.
 	#[cfg(feature = "runtime-benchmarks")]
 	fn store_code_raw(code: Vec<u8>) -> frame_support::dispatch::DispatchResult {
-		let schedule = <Pallet<T>>::current_schedule();
+		let schedule = <CurrentSchedule<T>>::get();
 		PrefabWasmModule::store_code_unchecked(code, &schedule)?;
 		Ok(())
 	}
@@ -760,127 +769,3 @@ where
 		self::wasm::reinstrument(module, schedule)
 	}
 }
-
-/// Information for managing an account and its sub trie abstraction.
-/// This is the required info to cache for an account
-#[derive(Encode, Decode, RuntimeDebug)]
-pub enum ContractInfo<T: Config> {
-	Alive(AliveContractInfo<T>),
-	Tombstone(TombstoneContractInfo<T>),
-}
-
-impl<T: Config> ContractInfo<T> {
-	/// If contract is alive then return some alive info
-	pub fn get_alive(self) -> Option<AliveContractInfo<T>> {
-		if let ContractInfo::Alive(alive) = self {
-			Some(alive)
-		} else {
-			None
-		}
-	}
-	/// If contract is alive then return some reference to alive info
-	pub fn as_alive(&self) -> Option<&AliveContractInfo<T>> {
-		if let ContractInfo::Alive(ref alive) = self {
-			Some(alive)
-		} else {
-			None
-		}
-	}
-	/// If contract is alive then return some mutable reference to alive info
-	pub fn as_alive_mut(&mut self) -> Option<&mut AliveContractInfo<T>> {
-		if let ContractInfo::Alive(ref mut alive) = self {
-			Some(alive)
-		} else {
-			None
-		}
-	}
-
-	/// If contract is tombstone then return some tombstone info
-	pub fn get_tombstone(self) -> Option<TombstoneContractInfo<T>> {
-		if let ContractInfo::Tombstone(tombstone) = self {
-			Some(tombstone)
-		} else {
-			None
-		}
-	}
-	/// If contract is tombstone then return some reference to tombstone info
-	pub fn as_tombstone(&self) -> Option<&TombstoneContractInfo<T>> {
-		if let ContractInfo::Tombstone(ref tombstone) = self {
-			Some(tombstone)
-		} else {
-			None
-		}
-	}
-	/// If contract is tombstone then return some mutable reference to tombstone info
-	pub fn as_tombstone_mut(&mut self) -> Option<&mut TombstoneContractInfo<T>> {
-		if let ContractInfo::Tombstone(ref mut tombstone) = self {
-			Some(tombstone)
-		} else {
-			None
-		}
-	}
-}
-
-/// Information for managing an account and its sub trie abstraction.
-/// This is the required info to cache for an account.
-#[derive(Encode, Decode, Clone, PartialEq, Eq, RuntimeDebug)]
-pub struct RawAliveContractInfo<CodeHash, Balance, BlockNumber> {
-	/// Unique ID for the subtree encoded as a bytes vector.
-	pub trie_id: TrieId,
-	/// The total number of bytes used by this contract.
-	///
-	/// It is a sum of each key-value pair stored by this contract.
-	pub storage_size: u32,
-	/// The total number of key-value pairs in storage of this contract.
-	pub pair_count: u32,
-	/// The code associated with a given account.
-	pub code_hash: CodeHash,
-	/// Pay rent at most up to this value.
-	pub rent_allowance: Balance,
-	/// The amount of rent that was payed by the contract over its whole lifetime.
-	///
-	/// A restored contract starts with a value of zero just like a new contract.
-	pub rent_payed: Balance,
-	/// Last block rent has been payed.
-	pub deduct_block: BlockNumber,
-	/// Last block child storage has been written.
-	pub last_write: Option<BlockNumber>,
-	/// This field is reserved for future evolution of format.
-	pub _reserved: Option<()>,
-}
-
-impl<CodeHash, Balance, BlockNumber> RawAliveContractInfo<CodeHash, Balance, BlockNumber> {
-	/// Associated child trie unique id is built from the hash part of the trie id.
-	pub fn child_trie_info(&self) -> ChildInfo {
-		child_trie_info(&self.trie_id[..])
-	}
-}
-
-/// Associated child trie unique id is built from the hash part of the trie id.
-pub(crate) fn child_trie_info(trie_id: &[u8]) -> ChildInfo {
-	ChildInfo::new_default(trie_id)
-}
-
-#[derive(Encode, Decode, PartialEq, Eq, RuntimeDebug)]
-pub struct RawTombstoneContractInfo<H, Hasher>(H, PhantomData<Hasher>);
-
-impl<H, Hasher> RawTombstoneContractInfo<H, Hasher>
-where
-	H: Member + MaybeSerializeDeserialize+ Debug
-		+ AsRef<[u8]> + AsMut<[u8]> + Copy + Default
-		+ sp_std::hash::Hash + Codec,
-	Hasher: Hash<Output=H>,
-{
-	fn new(storage_root: &[u8], code_hash: H) -> Self {
-		let mut buf = Vec::new();
-		storage_root.using_encoded(|encoded| buf.extend_from_slice(encoded));
-		buf.extend_from_slice(code_hash.as_ref());
-		RawTombstoneContractInfo(<Hasher as Hash>::hash(&buf[..]), PhantomData)
-	}
-}
-
-impl<T: Config> From<AliveContractInfo<T>> for ContractInfo<T> {
-	fn from(alive_info: AliveContractInfo<T>) -> Self {
-		Self::Alive(alive_info)
-	}
-}

substrate/frame/contracts/src/schedule.rs

@@ -39,7 +39,11 @@ pub const API_BENCHMARK_BATCH_SIZE: u32 = 100;
 /// as for `API_BENCHMARK_BATCH_SIZE`.
 pub const INSTR_BENCHMARK_BATCH_SIZE: u32 = 1_000;
 
-/// Definition of the cost schedule and other parameterizations for wasm vm.
+/// Definition of the cost schedule and other parameterizations for the wasm vm.
+///
+/// Its fields are private to the crate in order to allow addition of new contract
+/// callable functions without bumping to a new major version. A genesis config should
+/// rely on public functions of this type.
 #[cfg_attr(feature = "std", derive(Serialize, Deserialize))]
 #[cfg_attr(feature = "std", serde(bound(serialize = "", deserialize = "")))]
 #[derive(Clone, Encode, Decode, PartialEq, Eq, ScheduleDebug)]
@@ -53,20 +57,20 @@ pub struct Schedule<T: Config> {
 	/// of all contracts which are triggered by a version comparison on call.
 	/// Changes to other parts of the schedule should not increment the version in
 	/// order to avoid unnecessary re-instrumentations.
-	pub version: u32,
+	pub(crate) version: u32,
 
 	/// Whether the `seal_println` function is allowed to be used contracts.
 	/// MUST only be enabled for `dev` chains, NOT for production chains
-	pub enable_println: bool,
+	pub(crate) enable_println: bool,
 
 	/// Describes the upper limits on various metrics.
-	pub limits: Limits,
+	pub(crate) limits: Limits,
 
 	/// The weights for individual wasm instructions.
-	pub instruction_weights: InstructionWeights<T>,
+	pub(crate) instruction_weights: InstructionWeights<T>,
 
 	/// The weights for each imported function a contract is allowed to call.
-	pub host_fn_weights: HostFnWeights<T>,
+	pub(crate) host_fn_weights: HostFnWeights<T>,
 }
 
 /// Describes the upper limits on various metrics.
@@ -602,7 +606,21 @@ struct ScheduleRules<'a, T: Config> {
 }
 
 impl<T: Config> Schedule<T> {
-	pub fn rules(&self, module: &elements::Module) -> impl rules::Rules + '_ {
+	/// Allow contracts to call `seal_println` in order to print messages to the console.
+	///
+	/// This should only ever be activated in development chains. The printed messages
+	/// can be observed on the console by setting the environment variable
+	/// `RUST_LOG=runtime=debug` when running the node.
+	///
+	/// # Note
+	///
+	/// Is set to `false` by default.
+	pub fn enable_println(mut self, enable: bool) -> Self {
+		self.enable_println = enable;
+		self
+	}
+
+	pub(crate) fn rules(&self, module: &elements::Module) -> impl rules::Rules + '_ {
 		ScheduleRules {
 			schedule: &self,
 			params: module

substrate/frame/contracts/src/storage.rs

@@ -19,23 +19,131 @@
 
 use crate::{
 	exec::{AccountIdOf, StorageKey},
-	AliveContractInfo, BalanceOf, CodeHash, ContractInfo, ContractInfoOf, Config, TrieId,
+	BalanceOf, CodeHash, ContractInfoOf, Config, TrieId,
 	AccountCounter, DeletionQueue, Error,
 	weights::WeightInfo,
 };
-use codec::{Encode, Decode};
+use codec::{Codec, Encode, Decode};
 use sp_std::prelude::*;
-use sp_std::marker::PhantomData;
+use sp_std::{marker::PhantomData, fmt::Debug};
 use sp_io::hashing::blake2_256;
-use sp_runtime::traits::{Bounded, Saturating, Zero};
+use sp_runtime::{
+	RuntimeDebug,
+	traits::{Bounded, Saturating, Zero, Hash, Member, MaybeSerializeDeserialize},
+};
 use sp_core::crypto::UncheckedFrom;
 use frame_support::{
 	dispatch::{DispatchError, DispatchResult},
-	storage::child::{self, KillChildStorageResult},
+	storage::child::{self, KillChildStorageResult, ChildInfo},
 	traits::Get,
 	weights::Weight,
 };
 
+pub type AliveContractInfo<T> =
+	RawAliveContractInfo<CodeHash<T>, BalanceOf<T>, <T as frame_system::Config>::BlockNumber>;
+pub type TombstoneContractInfo<T> =
+	RawTombstoneContractInfo<<T as frame_system::Config>::Hash, <T as frame_system::Config>::Hashing>;
+
+/// Information for managing an account and its sub trie abstraction.
+/// This is the required info to cache for an account
+#[derive(Encode, Decode, RuntimeDebug)]
+pub enum ContractInfo<T: Config> {
+	Alive(AliveContractInfo<T>),
+	Tombstone(TombstoneContractInfo<T>),
+}
+
+impl<T: Config> ContractInfo<T> {
+	/// If contract is alive then return some alive info
+	pub fn get_alive(self) -> Option<AliveContractInfo<T>> {
+		if let ContractInfo::Alive(alive) = self {
+			Some(alive)
+		} else {
+			None
+		}
+	}
+	/// If contract is alive then return some reference to alive info
+	pub fn as_alive(&self) -> Option<&AliveContractInfo<T>> {
+		if let ContractInfo::Alive(ref alive) = self {
+			Some(alive)
+		} else {
+			None
+		}
+	}
+
+	/// If contract is tombstone then return some tombstone info
+	pub fn get_tombstone(self) -> Option<TombstoneContractInfo<T>> {
+		if let ContractInfo::Tombstone(tombstone) = self {
+			Some(tombstone)
+		} else {
+			None
+		}
+	}
+}
+
+/// Information for managing an account and its sub trie abstraction.
+/// This is the required info to cache for an account.
+#[derive(Encode, Decode, Clone, PartialEq, Eq, RuntimeDebug)]
+pub struct RawAliveContractInfo<CodeHash, Balance, BlockNumber> {
+	/// Unique ID for the subtree encoded as a bytes vector.
+	pub trie_id: TrieId,
+	/// The total number of bytes used by this contract.
+	///
+	/// It is a sum of each key-value pair stored by this contract.
+	pub storage_size: u32,
+	/// The total number of key-value pairs in storage of this contract.
+	pub pair_count: u32,
+	/// The code associated with a given account.
+	pub code_hash: CodeHash,
+	/// Pay rent at most up to this value.
+	pub rent_allowance: Balance,
+	/// The amount of rent that was payed by the contract over its whole lifetime.
+	///
+	/// A restored contract starts with a value of zero just like a new contract.
+	pub rent_payed: Balance,
+	/// Last block rent has been payed.
+	pub deduct_block: BlockNumber,
+	/// Last block child storage has been written.
+	pub last_write: Option<BlockNumber>,
+	/// This field is reserved for future evolution of format.
+	pub _reserved: Option<()>,
+}
+
+impl<CodeHash, Balance, BlockNumber> RawAliveContractInfo<CodeHash, Balance, BlockNumber> {
+	/// Associated child trie unique id is built from the hash part of the trie id.
+	pub fn child_trie_info(&self) -> ChildInfo {
+		child_trie_info(&self.trie_id[..])
+	}
+}
+
+/// Associated child trie unique id is built from the hash part of the trie id.
+fn child_trie_info(trie_id: &[u8]) -> ChildInfo {
+	ChildInfo::new_default(trie_id)
+}
+
+#[derive(Encode, Decode, PartialEq, Eq, RuntimeDebug)]
+pub struct RawTombstoneContractInfo<H, Hasher>(H, PhantomData<Hasher>);
+
+impl<H, Hasher> RawTombstoneContractInfo<H, Hasher>
+where
+	H: Member + MaybeSerializeDeserialize+ Debug
+		+ AsRef<[u8]> + AsMut<[u8]> + Copy + Default
+		+ sp_std::hash::Hash + Codec,
+	Hasher: Hash<Output=H>,
+{
+	pub fn new(storage_root: &[u8], code_hash: H) -> Self {
+		let mut buf = Vec::new();
+		storage_root.using_encoded(|encoded| buf.extend_from_slice(encoded));
+		buf.extend_from_slice(code_hash.as_ref());
+		RawTombstoneContractInfo(<Hasher as Hash>::hash(&buf[..]), PhantomData)
+	}
+}
+
+impl<T: Config> From<AliveContractInfo<T>> for ContractInfo<T> {
+	fn from(alive_info: AliveContractInfo<T>) -> Self {
+		Self::Alive(alive_info)
+	}
+}
+
 /// An error that means that the account requested either doesn't exist or represents a tombstone
 /// account.
 #[cfg_attr(test, derive(PartialEq, Eq, Debug))]
@@ -59,7 +167,7 @@ where
 	/// The read is performed from the `trie_id` only. The `address` is not necessary. If the contract
 	/// doesn't store under the given `key` `None` is returned.
 	pub fn read(trie_id: &TrieId, key: &StorageKey) -> Option<Vec<u8>> {
-		child::get_raw(&crate::child_trie_info(&trie_id), &blake2_256(key))
+		child::get_raw(&child_trie_info(&trie_id), &blake2_256(key))
 	}
 
 	/// Update a storage entry into a contract's kv storage.
@@ -87,7 +195,7 @@ where
 		};
 
 		let hashed_key = blake2_256(key);
-		let child_trie_info = &crate::child_trie_info(&trie_id);
+		let child_trie_info = &child_trie_info(&trie_id);
 
 		let opt_prev_len = child::len(&child_trie_info, &hashed_key);
 
@@ -257,7 +365,7 @@ where
 			let trie = &mut queue[0];
 			let pair_count = trie.pair_count;
 			let outcome = child::kill_storage(
-				&crate::child_trie_info(&trie.trie_id),
+				&child_trie_info(&trie.trie_id),
 				Some(remaining_key_budget),
 			);
 			if pair_count > remaining_key_budget {
@@ -290,7 +398,6 @@ where
 	/// This generator uses inner counter for account id and applies the hash over `AccountId +
 	/// accountid_counter`.
 	pub fn generate_trie_id(account_id: &AccountIdOf<T>) -> TrieId {
-		use sp_runtime::traits::Hash;
 		// Note that skipping a value due to error is not an issue here.
 		// We only need uniqueness, not sequence.
 		let new_seed = <AccountCounter<T>>::mutate(|v| {

substrate/frame/contracts/src/tests.rs

@@ -17,7 +17,7 @@
 
 use crate::{
 	BalanceOf, ContractInfo, ContractInfoOf, Pallet,
-	RawAliveContractInfo, Config, Schedule,
+	Config, Schedule,
 	Error, storage::Storage,
 	chain_extension::{
 		Result as ExtensionResult, Environment, ChainExtension, Ext, SysConfig, RetVal,
@@ -26,6 +26,7 @@ use crate::{
 	exec::{AccountIdOf, Executable}, wasm::PrefabWasmModule,
 	weights::WeightInfo,
 	wasm::ReturnCode as RuntimeReturnCode,
+	storage::RawAliveContractInfo,
 };
 use assert_matches::assert_matches;
 use codec::Encode;

substrate/frame/contracts/src/wasm/prepare.rs

@@ -519,7 +519,7 @@ pub mod benchmarking {
 #[cfg(test)]
 mod tests {
 	use super::*;
-	use crate::{exec::Ext, Limits};
+	use crate::{exec::Ext, schedule::Limits};
 	use std::fmt;
 
 	impl fmt::Debug for PrefabWasmModule<crate::tests::Test> {

substrate/frame/contracts/src/wasm/runtime.rs

@@ -18,10 +18,11 @@
 //! Environment definition of the wasm smart-contract runtime.
 
 use crate::{
-	HostFnWeights, Config, CodeHash, BalanceOf, Error,
+	Config, CodeHash, BalanceOf, Error,
 	exec::{Ext, StorageKey, TopicOf},
 	gas::{GasMeter, Token, ChargedAmount},
 	wasm::env_def::ConvertibleToWasm,
+	schedule::HostFnWeights,
 };
 use parity_wasm::elements::ValueType;
 use frame_support::{dispatch::DispatchError, ensure, traits::Get, weights::Weight};