Generate storage info for pallet im_online (#9654)

* Integrating WrapperOpaque from PR #9738

* Adding storage_info to pallet im-online
Changing some `Vec` to `WeakBoundedVec`
Adding the following bounds:
* `MaxKeys
* `MaxPeerInHeartbeats`
* `MaxPeerDataEncodingSize`
to limit the size of `WeakBoundedVec`

* Fix syntax

* Need to clone keys

* Changes in formatting

substrate/frame/support/src/traits.rs

@@ -52,7 +52,7 @@ mod misc;
 pub use misc::{
 	Backing, ConstU32, EnsureInherentsAreFirst, EstimateCallFee, ExecuteBlock, ExtrinsicCall, Get,
 	GetBacking, GetDefault, HandleLifetime, IsSubType, IsType, Len, OffchainWorker,
-	OnKilledAccount, OnNewAccount, SameOrOther, Time, TryDrop, UnixTime,
+	OnKilledAccount, OnNewAccount, SameOrOther, Time, TryDrop, UnixTime, WrapperOpaque,
 };
 
 mod stored_map;

substrate/frame/support/src/traits/misc.rs

@@ -17,8 +17,10 @@
 
 //! Smaller traits used in FRAME which don't need their own file.
 
-use crate::dispatch::Parameter;
+use crate::{dispatch::Parameter, TypeInfo};
+use codec::{Decode, Encode, EncodeLike, Input, MaxEncodedLen};
 use sp_runtime::{traits::Block as BlockT, DispatchError};
+use sp_std::vec::Vec;
 
 /// Anything that can have a `::len()` method.
 pub trait Len {
@@ -377,3 +379,48 @@ impl<Call, Balance: From<u32>, const T: u32> EstimateCallFee<Call, Balance> for
 		T.into()
 	}
 }
+
+/// A wrapper for any type `T` which implement encode/decode in a way compatible with `Vec<u8>`.
+///
+/// The encoding is the encoding of `T` prepended with the compact encoding of its size in bytes.
+/// Thus the encoded value can be decoded as a `Vec<u8>`.
+#[derive(Debug, Eq, PartialEq, Default, Clone, MaxEncodedLen, TypeInfo)]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
+pub struct WrapperOpaque<T>(pub T);
+
+impl<T: Encode> EncodeLike for WrapperOpaque<T> {}
+
+impl<T: Encode> Encode for WrapperOpaque<T> {
+	fn size_hint(&self) -> usize {
+		// Compact<u32> usually takes at most 4 bytes
+		self.0.size_hint().saturating_add(4)
+	}
+
+	fn encode_to<O: codec::Output + ?Sized>(&self, dest: &mut O) {
+		self.0.encode().encode_to(dest);
+	}
+
+	fn encode(&self) -> Vec<u8> {
+		self.0.encode().encode()
+	}
+
+	fn using_encoded<R, F: FnOnce(&[u8]) -> R>(&self, f: F) -> R {
+		self.0.encode().using_encoded(f)
+	}
+}
+
+impl<T: Decode> Decode for WrapperOpaque<T> {
+	fn decode<I: Input>(input: &mut I) -> Result<Self, codec::Error> {
+		Ok(Self(T::decode(&mut &<Vec<u8>>::decode(input)?[..])?))
+	}
+
+	fn skip<I: Input>(input: &mut I) -> Result<(), codec::Error> {
+		<Vec<u8>>::skip(input)
+	}
+}
+
+impl<T> From<T> for WrapperOpaque<T> {
+	fn from(t: T) -> Self {
+		Self(t)
+	}
+}

substrate/frame/support/src/traits/validation.rs

@@ -18,7 +18,7 @@
 //! Traits for dealing with validation and validators.
 
 use crate::{dispatch::Parameter, weights::Weight};
-use codec::{Codec, Decode};
+use codec::{Codec, Decode, MaxEncodedLen};
 use sp_runtime::{
 	traits::{Convert, Zero},
 	BoundToRuntimeAppPublic, ConsensusEngineId, Permill, RuntimeAppPublic,
@@ -31,7 +31,7 @@ use sp_std::prelude::*;
 /// Something that can give information about the current validator set.
 pub trait ValidatorSet<AccountId> {
 	/// Type for representing validator id in a session.
-	type ValidatorId: Parameter;
+	type ValidatorId: Parameter + MaxEncodedLen;
 	/// A type for converting `AccountId` to `ValidatorId`.
 	type ValidatorIdOf: Convert<AccountId, Option<Self::ValidatorId>>;