lib.rs

// Copyright 2017-2019 Parity Technologies (UK) Ltd.
// This file is part of Substrate.

// Substrate is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// Substrate is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.

//! # System Module
//!
//! The System module provides low-level access to core types and cross-cutting utilities.
//! It acts as the base layer for other SRML modules to interact with the Substrate framework components.
//!
//! - [`system::Trait`](./trait.Trait.html)
//!
//! ## Overview
//!
//! The System module defines the core data types used in a Substrate runtime.
//! It also provides several utility functions (see [`Module`](./struct.Module.html)) for other runtime modules.
//!
//! In addition, it manages the storage items for extrinsics data, indexes, event records, and digest items,
//! among other things that support the execution of the current block.
//!
//! It also handles low-level tasks like depositing logs, basic set up and take down of
//! temporary storage entries, and access to previous block hashes.
//!
//! ## Interface
//!
//! ### Dispatchable Functions
//!
//! The System module does not implement any dispatchable functions.
//!
//! ### Public Functions
//!
//! See the [`Module`](./struct.Module.html) struct for details of publicly available functions.
//!
//! ### Signed Extensions
//!
//! The system module defines the following extensions:
//!
//!   - [`CheckWeight`]: Checks the weight and length of the block and ensure that it does not
//!     exceed the limits.
//!   - [`CheckNonce`]: Checks the nonce of the transaction. Contains a single payload of type
//!     `T::Index`.
//!   - [`CheckEra`]: Checks the era of the transaction. Contains a single payload of type `Era`.
//!   - [`CheckGenesis`]: Checks the provided genesis hash of the transaction. Must be a part of the
//!     signed payload of the transaction.
//!   - [`CheckVersion`]: Checks that the runtime version is the same as the one encoded in the
//!     transaction.
//!
//! Lookup the runtime aggregator file (e.g. `node/runtime`) to see the full list of signed
//! extensions included in a chain.
//!
//! ## Usage
//!
//! ### Prerequisites
//!
//! Import the System module and derive your module's configuration trait from the system trait.
//!
//! ### Example - Get extrinsic count and parent hash for the current block
//!
//! ```
//! use support::{decl_module, dispatch};
//! use frame_system::{self as system, ensure_signed};
//!
//! pub trait Trait: system::Trait {}
//!
//! decl_module! {
//! 	pub struct Module<T: Trait> for enum Call where origin: T::Origin {
//! 		pub fn system_module_example(origin) -> dispatch::Result {
//! 			let _sender = ensure_signed(origin)?;
//! 			let _extrinsic_count = <system::Module<T>>::extrinsic_count();
//! 			let _parent_hash = <system::Module<T>>::parent_hash();
//! 			Ok(())
//! 		}
//! 	}
//! }
//! # fn main() { }
//! ```

#![cfg_attr(not(feature = "std"), no_std)]

#[cfg(feature = "std")]
use serde::Serialize;
use sp_std::prelude::*;
#[cfg(any(feature = "std", test))]
use sp_std::map;
use sp_std::marker::PhantomData;
use sp_std::fmt::Debug;
use sp_version::RuntimeVersion;
use sp_runtime::{
	RuntimeDebug,
	generic::{self, Era}, Perbill, DispatchOutcome, DispatchError,
	transaction_validity::{
		ValidTransaction, TransactionPriority, TransactionLongevity, TransactionValidityError,
		InvalidTransaction, TransactionValidity,
	},
	traits::{
		self, CheckEqual, SimpleArithmetic, Zero, SignedExtension, Lookup, LookupError,
		SimpleBitOps, Hash, Member, MaybeDisplay, EnsureOrigin, SaturatedConversion,
		MaybeSerialize, MaybeSerializeDeserialize, StaticLookup, One, Bounded,
	},
};

use primitives::storage::well_known_keys;
use support::{
	decl_module, decl_event, decl_storage, decl_error, storage, Parameter,
	traits::{Contains, Get},
	weights::{Weight, DispatchInfo, DispatchClass, SimpleDispatchInfo},
};
use codec::{Encode, Decode};

#[cfg(any(feature = "std", test))]
use runtime_io::TestExternalities;

#[cfg(any(feature = "std", test))]
use primitives::ChangesTrieConfiguration;

pub mod offchain;

/// Handler for when a new account has been created.
#[impl_trait_for_tuples::impl_for_tuples(30)]
pub trait OnNewAccount<AccountId> {
	/// A new account `who` has been registered.
	fn on_new_account(who: &AccountId);
}

/// Determiner to say whether a given account is unused.
pub trait IsDeadAccount<AccountId> {
	/// Is the given account dead?
	fn is_dead_account(who: &AccountId) -> bool;
}

impl<AccountId> IsDeadAccount<AccountId> for () {
	fn is_dead_account(_who: &AccountId) -> bool {
		true
	}
}

/// Compute the trie root of a list of extrinsics.
pub fn extrinsics_root<H: Hash, E: codec::Encode>(extrinsics: &[E]) -> H::Output {
	extrinsics_data_root::<H>(extrinsics.iter().map(codec::Encode::encode).collect())
}

/// Compute the trie root of a list of extrinsics.
pub fn extrinsics_data_root<H: Hash>(xts: Vec<Vec<u8>>) -> H::Output {
	H::ordered_trie_root(xts)
}

pub trait Trait: 'static + Eq + Clone {
	/// The aggregated `Origin` type used by dispatchable calls.
	type Origin:
		Into<Result<RawOrigin<Self::AccountId>, Self::Origin>> + From<RawOrigin<Self::AccountId>>;

	/// The aggregated `Call` type.
	type Call: Debug;

	/// Account index (aka nonce) type. This stores the number of previous transactions associated
	/// with a sender account.
	type Index:
		Parameter + Member + MaybeSerialize + Debug + Default + MaybeDisplay + SimpleArithmetic
		+ Copy;

	/// The block number type used by the runtime.
	type BlockNumber:
		Parameter + Member + MaybeSerializeDeserialize + Debug + MaybeDisplay + SimpleArithmetic
		+ Default + Bounded + Copy + sp_std::hash::Hash;

	/// The output of the `Hashing` function.
	type Hash:
		Parameter + Member + MaybeSerializeDeserialize + Debug + MaybeDisplay + SimpleBitOps
		+ Default + Copy + CheckEqual + sp_std::hash::Hash + AsRef<[u8]> + AsMut<[u8]>;

	/// The hashing system (algorithm) being used in the runtime (e.g. Blake2).
	type Hashing: Hash<Output = Self::Hash>;

	/// The user account identifier type for the runtime.
	type AccountId: Parameter + Member + MaybeSerializeDeserialize + Debug + MaybeDisplay + Ord
		+ Default;

	/// Converting trait to take a source type and convert to `AccountId`.
	///
	/// Used to define the type and conversion mechanism for referencing accounts in transactions.
	/// It's perfectly reasonable for this to be an identity conversion (with the source type being
	/// `AccountId`), but other modules (e.g. Indices module) may provide more functional/efficient
	/// alternatives.
	type Lookup: StaticLookup<Target = Self::AccountId>;

	/// The block header.
	type Header: Parameter + traits::Header<
		Number = Self::BlockNumber,
		Hash = Self::Hash,