Bring support for calling check_inherents (#490)

* Start

* More work

* Add proc-macro for `validate_block`

* Make everything compile

* Add some test

Cargo.toml

@@ -11,6 +11,7 @@ members = [
 	"pallets/collator-selection",
 	"pallets/dmp-queue",
 	"pallets/parachain-system",
+	"pallets/parachain-system/proc-macro",
 	"pallets/session-benchmarking",
 	"pallets/xcm",
 	"pallets/xcmp-queue",

pallets/aura-ext/src/lib.rs

@@ -25,10 +25,12 @@
 //! ```
 //!# struct Runtime;
 //!# struct Executive;
-//! cumulus_pallet_parachain_system::register_validate_block!(
-//!     Runtime,
-//!     cumulus_pallet_aura_ext::BlockExecutor::<Runtime, Executive>,
-//! );
+//!# struct CheckInherents;
+//! cumulus_pallet_parachain_system::register_validate_block! {
+//!     Runtime = Runtime,
+//!     BlockExecutor = cumulus_pallet_aura_ext::BlockExecutor::<Runtime, Executive>,
+//!     CheckInherents = CheckInherents,
+//! }
 //! ```
 
 #![cfg_attr(not(feature = "std"), no_std)]

pallets/parachain-system/Cargo.toml

@@ -9,6 +9,7 @@ description = "Base pallet for cumulus-based parachains"
 # Cumulus dependencies
 cumulus-primitives-core = { path = "../../primitives/core", default-features = false }
 cumulus-primitives-parachain-inherent = { path = "../../primitives/parachain-inherent", default-features = false }
+cumulus-pallet-parachain-system-proc-macro = { path = "proc-macro", default-features = false }
 
 # Polkadot dependencies
 polkadot-parachain = { git = "https://github.com/paritytech/polkadot", default-features = false, features = [ "wasm-api" ], branch = "master" }
@@ -31,10 +32,7 @@ sp-externalities = { git = "https://github.com/paritytech/substrate", default-fe
 # Other Dependencies
 codec = { package = "parity-scale-codec", version = "2.0.0", default-features = false, features = ["derive"]}
 serde = { version = "1.0.101", optional = true, features = ["derive"] }
-hash-db = { version = "0.15.2", default-features = false }
 log = { version = "0.4.14", default-features = false }
-memory-db = { version = "0.26.0", default-features = false }
-trie-db = { version = "0.22.0", default-features = false }
 environmental = { version = "1.1.2", default-features = false }
 
 [dev-dependencies]
@@ -63,16 +61,14 @@ std = [
 	"sp-runtime/std",
 	"sp-io/std",
 	"sp-std/std",
-	"hash-db/std",
 	"log/std",
-	"memory-db/std",
-	"trie-db/std",
 	"sp-state-machine/std",
 	"sp-trie/std",
 	"sp-externalities/std",
 	"frame-system/std",
 	"cumulus-primitives-core/std",
 	"cumulus-primitives-parachain-inherent/std",
+	"cumulus-pallet-parachain-system-proc-macro/std",
 	"environmental/std",
 	"xcm/std"
 ]

pallets/parachain-system/proc-macro/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "cumulus-pallet-parachain-system-proc-macro"
+version = "0.1.0"
+authors = ["Parity Technologies <[email protected]>"]
+edition = "2018"
+description = "Proc macros provided by the parachain-system pallet"
+
+[lib]
+proc-macro = true
+
+[dependencies]
+syn = "1.0.73"
+proc-macro2 = "1.0.27"
+quote = "1.0.9"
+proc-macro-crate = "1.0.0"
+
+[features]
+default = [ "std" ]
+std = []

pallets/parachain-system/proc-macro/src/lib.rs

@@ -0,0 +1,144 @@
+// Copyright 2021 Parity Technologies (UK) Ltd.
+// This file is part of Cumulus.
+
+// Cumulus 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.
+
+// Cumulus 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 Cumulus.  If not, see <http://www.gnu.org/licenses/>.
+
+use proc_macro2::{Span, TokenStream};
+use proc_macro_crate::{crate_name, FoundCrate};
+use syn::{
+	parse::{Parse, ParseStream},
+	spanned::Spanned,
+	token, Error, Ident, Path,
+};
+
+mod keywords {
+	syn::custom_keyword!(Runtime);
+	syn::custom_keyword!(BlockExecutor);
+	syn::custom_keyword!(CheckInherents);
+}
+
+struct Input {
+	runtime: Path,
+	block_executor: Path,
+	check_inherents: Path,
+}
+
+impl Parse for Input {
+	fn parse(input: ParseStream) -> Result<Self, Error> {
+		let mut runtime = None;
+		let mut block_executor = None;
+		let mut check_inherents = None;
+
+		fn parse_inner<KW: Parse + Spanned>(
+			input: ParseStream,
+			result: &mut Option<Path>,
+		) -> Result<(), Error> {
+			let kw = input.parse::<KW>()?;
+
+			if result.is_none() {
+				input.parse::<token::Eq>()?;
+				*result = Some(input.parse::<Path>()?);
+				if input.peek(token::Comma) {
+					input.parse::<token::Comma>()?;
+				}
+
+				Ok(())
+			} else {
+				Err(Error::new(kw.span(), "Is only allowed to be passed once"))
+			}
+		}
+
+		while runtime.is_none() || block_executor.is_none() || check_inherents.is_none() {
+			let lookahead = input.lookahead1();
+
+			if lookahead.peek(keywords::Runtime) {
+				parse_inner::<keywords::Runtime>(input, &mut runtime)?;
+			} else if lookahead.peek(keywords::BlockExecutor) {
+				parse_inner::<keywords::BlockExecutor>(input, &mut block_executor)?;
+			} else if lookahead.peek(keywords::CheckInherents) {
+				parse_inner::<keywords::CheckInherents>(input, &mut check_inherents)?;
+			} else {
+				return Err(lookahead.error());
+			}
+		}
+
+		let rest = input.parse::<TokenStream>()?;
+		if !rest.is_empty() {
+			return Err(Error::new(rest.span(), "Unexpected input data"));
+		}
+
+		Ok(Self {
+			runtime: runtime.expect("Everything is parsed before; qed"),
+			block_executor: block_executor.expect("Everything is parsed before; qed"),
+			check_inherents: check_inherents.expect("Everything is parsed before; qed"),
+		})
+	}
+}
+
+fn crate_() -> Result<Ident, Error> {
+	match crate_name("cumulus-pallet-parachain-system") {
+		Ok(FoundCrate::Itself) => Ok(syn::Ident::new(
+			"cumulus_pallet_parachain_system",
+			Span::call_site(),
+		)),
+		Ok(FoundCrate::Name(name)) => Ok(Ident::new(&name, Span::call_site())),
+		Err(e) => Err(Error::new(Span::call_site(), e)),
+	}
+}
+
+#[proc_macro]
+pub fn register_validate_block(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+	let Input {
+		runtime,
+		check_inherents,
+		block_executor,
+	} = match syn::parse(input) {
+		Ok(t) => t,
+		Err(e) => return e.into_compile_error().into(),
+	};
+
+	let crate_ = match crate_() {
+		Ok(c) => c,
+		Err(e) => return e.into_compile_error().into(),
+	};
+
+	if cfg!(not(feature = "std")) {
+		quote::quote! {
+			#[doc(hidden)]
+			mod parachain_validate_block {
+				use super::*;
+
+				#[no_mangle]
+				unsafe fn validate_block(arguments: *const u8, arguments_len: usize) -> u64 {
+					let params = #crate_::validate_block::polkadot_parachain::load_params(
+						arguments,
+						arguments_len,
+					);
+
+					let res = #crate_::validate_block::implementation::validate_block::<
+						<#runtime as #crate_::validate_block::GetRuntimeBlockType>::RuntimeBlock,
+						#block_executor,
+						#runtime,
+						#check_inherents,
+					>(params);
+
+					#crate_::validate_block::polkadot_parachain::write_result(&res)
+				}
+			}
+		}
+	} else {
+		quote::quote!()
+	}
+	.into()
+}

pallets/parachain-system/src/lib.rs

@@ -30,8 +30,8 @@
 use cumulus_primitives_core::{
 	relay_chain, AbridgedHostConfiguration, ChannelStatus, CollationInfo, DmpMessageHandler,
 	GetChannelInfo, InboundDownwardMessage, InboundHrmpMessage, MessageSendError, OnValidationData,
-	OutboundHrmpMessage, ParaId, PersistedValidationData, UpwardMessage, UpwardMessageSender,
-	XcmpMessageHandler, XcmpMessageSource,
+	OutboundHrmpMessage, ParaId, UpwardMessage, UpwardMessageSender, XcmpMessageHandler,
+	XcmpMessageSource, PersistedValidationData,
 };
 use cumulus_primitives_parachain_inherent::ParachainInherentData;
 use frame_support::{
@@ -46,7 +46,7 @@ use frame_system::{ensure_none, ensure_root};
 use polkadot_parachain::primitives::RelayChainBlockNumber;
 use relay_state_snapshot::MessagingStateSnapshot;
 use sp_runtime::{
-	traits::{BlakeTwo256, Hash},
+	traits::{BlakeTwo256, Block as BlockT, Hash},
 	transaction_validity::{
 		InvalidTransaction, TransactionLongevity, TransactionSource, TransactionValidity,
 		ValidTransaction,
@@ -60,6 +60,31 @@ pub mod validate_block;
 #[cfg(test)]
 mod tests;
 
+/// Register the `validate_block` function that is used by parachains to validate blocks on a
+/// validator.
+///
+/// Does *nothing* when `std` feature is enabled.
+///
+/// Expects as parameters the runtime, a block executor and an inherent checker.
+///
+/// # Example
+///
+/// ```
+///     struct BlockExecutor;
+///     struct Runtime;
+///     struct CheckInherents;
+///
+///     cumulus_pallet_parachain_system::register_validate_block! {
+///         Runtime = Runtime,
+///         BlockExecutor = Executive,
+///         CheckInherents = CheckInherents,
+///     }
+///
+/// # fn main() {}
+/// ```
+pub use cumulus_pallet_parachain_system_proc_macro::register_validate_block;
+pub use relay_state_snapshot::RelayChainStateProof;
+
 pub use pallet::*;
 
 #[frame_support::pallet]
@@ -309,17 +334,19 @@ pub mod pallet {
 				}
 			}
 
-			let (host_config, relevant_messaging_state) =
-				match relay_state_snapshot::extract_from_proof(
-					T::SelfParaId::get(),
-					vfp.relay_parent_storage_root,
-					relay_chain_state,
-				) {
-					Ok(r) => r,
-					Err(err) => {
-						panic!("invalid relay chain merkle proof: {:?}", err);
-					}
-				};
+			let relay_state_proof = RelayChainStateProof::new(
+				T::SelfParaId::get(),
+				vfp.relay_parent_storage_root,
+				relay_chain_state,
+			)
+			.expect("Invalid relay chain state proof");
+
+			let host_config = relay_state_proof
+				.read_abridged_host_configuration()
+				.expect("Invalid host configuration in relay chain state proof");
+			let relevant_messaging_state = relay_state_proof
+				.read_messaging_state_snapshot()
+				.expect("Invalid messaging state in relay chain state proof");
 
 			<ValidationData<T>>::put(&vfp);
 			<RelevantMessagingState<T>>::put(relevant_messaging_state.clone());
@@ -999,3 +1026,15 @@ impl<T: Config> UpwardMessageSender for Pallet<T> {
 		Self::send_upward_message(message)
 	}
 }
+
+/// Something that can check the inherents of a block.
+pub trait CheckInherents<Block: BlockT> {
+	/// Check all inherents of the block.
+	///
+	/// This function gets passed all the extrinsics of the block, so it is up to the callee to
+	/// identify the inherents. The `validation_data` can be used to access the
+	fn check_inherents(
+		extrinsics: &[Block::Extrinsic],
+		validation_data: &RelayChainStateProof,
+	) -> frame_support::inherent::CheckInherentsResult;
+}