Batch signature verification (#5023)

* create parallel tasks extension

* make type system happy

* basic externalities

* test for dynamic extensions

* batching test

* remove premature verify_batch

* shnschnorrkel batch

* alter test

* shnschnorrkel test

* executive batching

* some docs

* also multi/any signatgures

* error propagation

* styling

* make verification extension optional

* experimental ed25519 parallelization

* some merge fallout

* utilize task executor

* merge fallout

* utilize task executor more

* another merge fallout

* feature-gate sp-io

* arrange toml

* fix no-std

* sr25519 batching and refactoring

* add docs

* fix name

* add newline

* fix block import test

* long sr25519 test

* blocking instead of parking

* move everything in crypto

* return batch_verify to check :)

* use condvars

* use multi-threaded executor for benches

* don't call via host interface

* try no spawning

* add true

* cleanup

* straighten batching

* remove signature check from this test (?)

* remove now pointless test

* remove another now useless test

* fix warnings

* Revert "remove another now useless test"

This reverts commit bbdec24bb67ed4373072daef7c863e1a8825bd8b.

* rethink the sp-io-part

* Revert "remove now pointless test"

This reverts commit 4d553066322e65782264caa6053d4cd5538df977.

* fix wording

* add  wording

* add todo and fix

* return check and fix

* add logging in sp-io

* Update primitives/io/src/batch_verifier.rs

Co-Authored-By: cheme <emericchevalier.pro@gmail.com>

* address review and use std condvar

* account for early exit

* address reivew

* address review

* more suggestions

* add docs for batch verification

* remove unused

* more review suggestions

* move to sp-runtime

* add expects

* remove blocks

* use entry

* Update primitives/io/src/batch_verifier.rs

Co-Authored-By: Bastian Köcher <bkchr@users.noreply.github.com>

* Update primitives/externalities/src/extensions.rs

Co-Authored-By: Bastian Köcher <bkchr@users.noreply.github.com>

* update overlooked note

* remove stupid return

* Update primitives/io/src/lib.rs

Co-Authored-By: Bastian Köcher <bkchr@users.noreply.github.com>

* Update primitives/io/src/lib.rs

Co-Authored-By: Bastian Köcher <bkchr@users.noreply.github.com>

* fix wording

* bump spec_version

Co-authored-by: cheme <emericchevalier.pro@gmail.com>
Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

substrate/primitives/externalities/src/lib.rs

@@ -32,6 +32,17 @@ pub use extensions::{Extension, Extensions, ExtensionStore};
 mod extensions;
 mod scope_limited;
 
+/// Externalities error.
+#[derive(Debug)]
+pub enum Error {
+	/// Same extension cannot be registered twice.
+	ExtensionAlreadyRegistered,
+	/// Extensions are not supported.
+	ExtensionsAreNotSupported,
+	/// Extension `TypeId` is not registered.
+	ExtensionIsNotRegistered(TypeId),
+}
+
 /// The Substrate externalities.
 ///
 /// Provides access to the storage and to other registered extensions.
@@ -198,10 +209,29 @@ pub trait Externalities: ExtensionStore {
 pub trait ExternalitiesExt {
 	/// Tries to find a registered extension and returns a mutable reference.
 	fn extension<T: Any + Extension>(&mut self) -> Option<&mut T>;
+
+	/// Register extension `ext`.
+	///
+	/// Should return error if extension is already registered or extensions are not supported.
+	fn register_extension<T: Extension>(&mut self, ext: T) -> Result<(), Error>;
+
+	/// Deregister and drop extension of `T` type.
+	///
+	/// Should return error if extension of type `T` is not registered or
+	/// extensions are not supported.
+	fn deregister_extension<T: Extension>(&mut self) -> Result<(), Error>;
 }
 
 impl ExternalitiesExt for &mut dyn Externalities {
 	fn extension<T: Any + Extension>(&mut self) -> Option<&mut T> {
 		self.extension_by_type_id(TypeId::of::<T>()).and_then(Any::downcast_mut)
 	}
+
+	fn register_extension<T: Extension>(&mut self, ext: T) -> Result<(), Error> {
+		self.register_extension_with_type_id(TypeId::of::<T>(), Box::new(ext))
+	}
+
+	fn deregister_extension<T: Extension>(&mut self) -> Result<(), Error> {
+		self.deregister_extension_by_type_id(TypeId::of::<T>())
+	}
 }