Reorganising the repository - external renames and moves (#4074)

* Adding first rough ouline of the repository structure

* Remove old CI stuff

* add title

* formatting fixes

* move node-exits job's script to scripts dir

* Move docs into subdir

* move to bin

* move maintainence scripts, configs and helpers into its own dir

* add .local to ignore

* move core->client

* start up 'test' area

* move test client

* move test runtime

* make test move compile

* Add dependencies rule enforcement.

* Fix indexing.

* Update docs to reflect latest changes

* Moving /srml->/paint

* update docs

* move client/sr-* -> primitives/

* clean old readme

* remove old broken code in rhd

* update lock

* Step 1.

* starting to untangle client

* Fix after merge.

* start splitting out client interfaces

* move children and blockchain interfaces

* Move trie and state-machine to primitives.

* Fix WASM builds.

* fixing broken imports

* more interface moves

* move backend and light to interfaces

* move CallExecutor

* move cli off client

* moving around more interfaces

* re-add consensus crates into the mix

* fix subkey path

* relieve client from executor

* starting to pull out client from grandpa

* move is_decendent_of out of client

* grandpa still depends on client directly

* lemme tests pass

* rename srml->paint

* Make it compile.

* rename interfaces->client-api

* Move keyring to primitives.

* fixup libp2p dep

* fix broken use

* allow dependency enforcement to fail

* move fork-tree

* Moving wasm-builder

* make env

* move build-script-utils

* fixup broken crate depdencies and names

* fix imports for authority discovery

* fix typo

* update cargo.lock

* fixing imports

* Fix paths and add missing crates

* re-add missing crates

substrate/primitives/externalities/src/extensions.rs

@@ -0,0 +1,137 @@
+// 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/>.
+
+//! Externalities extensions storage.
+//!
+//! Externalities support to register a wide variety custom extensions. The [`Extensions`] provides
+//! some convenience functionality to store and retrieve these extensions.
+//!
+//! It is required that each extension implements the [`Extension`] trait.
+
+use std::{collections::HashMap, any::{Any, TypeId}, ops::DerefMut};
+
+/// Marker trait for types that should be registered as [`Externalities`](crate::Externalities) extension.
+///
+/// As extensions are stored as `Box<Any>`, this trait should give more confidence that the correct
+/// type is registered and requested.
+pub trait Extension: Send + Any {
+	/// Return the extension as `&mut dyn Any`.
+	///
+	/// This is a trick to make the trait type castable into an `Any`.
+	fn as_mut_any(&mut self) -> &mut dyn Any;
+}
+
+/// Macro for declaring an extension that usable with [`Extensions`].
+///
+/// The extension will be an unit wrapper struct that implements [`Extension`], `Deref` and
+/// `DerefMut`. The wrapped type is given by the user.
+///
+/// # Example
+/// ```
+/// # use substrate_externalities::decl_extension;
+/// decl_extension! {
+///     /// Some test extension
+///     struct TestExt(String);
+/// }
+/// ```
+#[macro_export]
+macro_rules! decl_extension {
+	(
+		$( #[ $attr:meta ] )*
+		$vis:vis struct $ext_name:ident ($inner:ty);
+	) => {
+		$( #[ $attr ] )*
+		$vis struct $ext_name (pub $inner);
+
+		impl $crate::Extension for $ext_name {
+			fn as_mut_any(&mut self) -> &mut dyn std::any::Any {
+				self
+			}
+		}
+
+		impl std::ops::Deref for $ext_name {
+			type Target = $inner;
+
+			fn deref(&self) -> &Self::Target {
+				&self.0
+			}
+		}
+
+		impl std::ops::DerefMut for $ext_name {
+			fn deref_mut(&mut self) -> &mut Self::Target {
+				&mut self.0
+			}
+		}
+	}
+}
+
+/// Something that provides access to the [`Extensions`] store.
+///
+/// This is a super trait of the [`Externalities`](crate::Externalities).
+pub trait ExtensionStore {
+	/// Tries to find a registered extension by the given `type_id` and returns it as a `&mut dyn Any`.
+	///
+	/// It is advised to use [`ExternalitiesExt::extension`](crate::ExternalitiesExt::extension)
+	/// instead of this function to get type system support and automatic type downcasting.
+	fn extension_by_type_id(&mut self, type_id: TypeId) -> Option<&mut dyn Any>;
+}
+
+/// Stores extensions that should be made available through the externalities.
+#[derive(Default)]
+pub struct Extensions {
+	extensions: HashMap<TypeId, Box<dyn Extension>>,
+}
+
+impl Extensions {
+	/// Create new instance of `Self`.
+	pub fn new() -> Self {
+		Self::default()
+	}
+
+	/// Register the given extension.
+	pub fn register<E: Extension>(&mut self, ext: E) {
+		self.extensions.insert(ext.type_id(), Box::new(ext));
+	}
+
+	/// Return a mutable reference to the requested extension.
+	pub fn get_mut(&mut self, ext_type_id: TypeId) -> Option<&mut dyn Any> {
+		self.extensions.get_mut(&ext_type_id).map(DerefMut::deref_mut).map(Extension::as_mut_any)
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+
+	decl_extension! {
+		struct DummyExt(u32);
+	}
+	decl_extension! {
+		struct DummyExt2(u32);
+	}
+
+	#[test]
+	fn register_and_retrieve_extension() {
+		let mut exts = Extensions::new();
+		exts.register(DummyExt(1));
+		exts.register(DummyExt2(2));
+
+		let ext = exts.get_mut(TypeId::of::<DummyExt>()).expect("Extension is registered");
+		let ext_ty = ext.downcast_mut::<DummyExt>().expect("Downcasting works");
+
+		assert_eq!(ext_ty.0, 1);
+	}
+}